Surgical system and method for guiding a robotic manipulator

Abstract

A surgical system includes a tool for engaging a target site, a manipulator configured to support the tool, and a sensing system configured to detect one or more system conditions associated with one or more of the tool, the manipulator, the target site, or a combination thereof. A controller is coupled to the manipulator, and the sensing system is configured to operate the manipulator between a first mode for maintaining alignment of the tool relative to the target site according to a first constraint criterion and a second mode for maintaining alignment of the tool relative to the target site according to a second constraint criterion different from the first constraint criterion. The controller is further configured to change operation of the manipulator from the first mode to the second mode in response to determining that at least one of the one or more system conditions satisfies a predetermined condition.

Description

Technical Field

[0001] [Cross - Reference to Related Applications] This application claims the priority and all benefits of U.S. Provisional Patent Application No. 62 / 908,915, filed on October 1, 2019, the entire disclosure of which is incorporated herein by reference.

Background Art

[0002] Robot manipulators are frequently used to assist medical professionals in performing various conventional surgical procedures. For this purpose, a surgeon can use a surgical robot or another type of manipulator to guide, position, move, actuate, or otherwise manipulate various tools, components, prostheses, etc. during a surgical operation.

[0003] Surgical robots can be used to assist surgeons in performing many different types of surgical procedures and are commonly used in surgeries involving the correction, resection, or replacement of degenerated joints to improve patient mobility and reduce pain. As an illustrative example, in a hip replacement surgery, a surgeon replaces a portion of a patient's hip joint with an artificial prosthesis component. For this purpose, in a total hip arthroplasty, a surgeon typically removes a portion of the patient's femur to accommodate an artificial femoral component including a head, re - surfaces the acetabulum of the pelvis with a reamer, and prompts the attachment of a prosthetic cup shaped to receive the artificial femoral component.

[0004] Depending on the specific procedure being performed, the surgical robot can assist the surgeon in approaching the surgical site, removing portions of joints and / or bones, and can be used to attach prosthetic components, etc. For example, to attach a prosthetic cup to the acetabulum of the pelvis, the surgeon connects the cup to an impactor and applies force by striking the impactor (e.g., with a mallet, etc.) to implant the cup into the prepared acetabulum. To facilitate the attachment of the cup, the surgical robot helps to continuously align the impactor with respect to the acetabulum, and the surgeon carefully monitors the trajectory and depth of the cup during the impact to ensure proper alignment of the cup. Here, the reaming or resection of the acetabulum generally defines the intended position of the cup, which in turn defines the trajectory of the impact, which can be monitored via a tracker fixed to the pelvis that is tracked via a navigation system.

[0005] Depending on the configuration of the prosthetic component, the impact tool, and the surgical robot, it may be difficult to maintain a set trajectory with a particular approach and surgical technique, whereby misalignment of the cup or other prosthetic component often results from inappropriate alignment and / or application of impact force. Further, when the cup is implanted in the reamed acetabulum, the patient's body becomes effectively physically attached to the impactor and the surgical robot in one or more degrees of freedom. Here, since the surgical robot typically restricts the movement of the impactor relative to the trajectory based on a tracker fixed to the pelvis, the misalignment that can occur during impact between the cup and the trajectory sometimes leads to a "runaway" state where the impactor and the pelvis are simultaneously moved by the surgical robot trying to return the impact tool to an aligned state with the trajectory. Due to the physical connection between the surgical robot and the pelvis, this type of "runaway" state can result in unwanted movement of the patient and / or detachment of the implanted or partially implanted cup.

[0006] A similar "runaway" condition can occur during other surgical procedures that use various types of tools guided by a surgical robot. By way of non-limiting example, a tool including a powered surgical device can be used to drive an energy applicator configured to remove tissue at a surgical site. Here, under certain operating conditions, the energy applicator can engage the tissue in a manner that effectively creates a locked-up state between the energy applicator and the tissue. For example, when drilling a pilot hole into a pedicle of a vertebra, a rotating instrument or bar driving a drill bit can slip and catch on the bone. Again, the "runaway" condition can result in unwanted movement of the energy applicator that engages the patient and / or tissue such as bone.

[0007] Accordingly, a need remains in the art to address one or more of these deficiencies. SUMMARY OF THE INVENTION

[0008] This summary is provided to introduce a simplified form of a series of concepts that are further described below in the detailed description for implementing the invention. This summary is not intended to limit the scope of the claimed subject matter, nor does it necessarily identify all important or essential features of the claimed subject matter.

[0009] According to a first aspect, there is provided a surgical system including a tool for engaging a target site, a manipulator configured to support the tool, a sensing system configured to detect one or more system conditions associated with one or more of the tool, the manipulator, the target site, or combinations thereof, a controller coupled to the manipulator and the sensing system and configured to operate the manipulator between a first mode for maintaining alignment of the tool with respect to the target site according to a first constraint criterion and a second mode for maintaining alignment of the tool with respect to the target site according to a second constraint criterion different from the first constraint criterion, the controller further being configured to change an operation of the manipulator from the first mode to the second mode in response to determining that at least one of the one or more system conditions satisfies a predetermined condition.

[0010] According to a second aspect, there is provided a method of operating the surgical system of the first aspect.

[0011] According to a third aspect, there is provided a surgical system including a tool for engaging a target site along a trajectory, a manipulator configured to support the tool, at least one sensor configured to obtain a measurement indicative of a force generated between the target site and the manipulator, a controller coupled to the manipulator and the at least one sensing system and configured to operate the manipulator between a first mode for maintaining alignment of the tool with respect to the trajectory according to a first constraint criterion and a second mode for maintaining alignment of the tool with respect to the trajectory according to a second constraint criterion different from the first constraint criterion, the controller further being configured to change an operation of the manipulator from the first mode to the second mode in response to determining that the force satisfies a predetermined condition.

[0012] According to a fourth aspect, there is provided a method of operating the surgical system of the third aspect.

[0013] According to a fifth aspect, there is provided a surgical system including a tool for engaging a target site, a manipulator configured to support the tool with respect to the target site, a patient tracker adapted for attachment to the target site, a navigation system configured to track the state of the patient tracker, and a controller coupled to the manipulator and the navigation system and configured to operate the manipulator between a first mode for maintaining alignment of the tool with respect to the target site according to a first constraint criterion and a second mode for maintaining alignment of the tool with respect to the target site according to a second constraint criterion different from the first constraint criterion, the controller being further configured to compare the tracked movement of the tool with the movement of the patient tracker based on the tracking state received from the navigation system, and further configured to change the operation of the manipulator from the first mode to the second mode in response to a determination that the tracked movement of the tool coincides with the movement of the patient tracker.

[0014] According to a sixth aspect, there is provided a method of operating the surgical system of the fifth aspect.

[0015] According to a seventh aspect, a method of operating a surgical system including an impactor assembly having an interface for releasably securing a prosthesis, a guide having a channel configured to receive the impactor assembly, a manipulator configured to support the guide relative to a target site along a track, at least one sensor, and a controller coupled to the manipulator and the at least one sensor, the controller operating the manipulator in a first mode to maintain alignment of the guide with respect to the track according to a first constraint criterion, operating the manipulator in a second mode to maintain alignment of the guide with respect to the track according to a second constraint criterion different from the first constraint criterion, detecting a force generated between the target site and the manipulator based on measurements from the at least one sensor, and determining that the force satisfies a predetermined condition and responsive thereto, changing the operation of the manipulator from the first mode to the second mode is provided.

[0016] According to a seventh aspect, a surgical system is provided that includes a tool for engaging a target site, a manipulator configured to support the tool, a sensing system configured to detect one or more system conditions associated with one or more of the tool, the manipulator, the target site, or combinations thereof, and a controller coupled to the manipulator and the sensing system, the controller operating the manipulator to maintain alignment of the tool with respect to the target site according to a first constraint criterion and operating the manipulator to maintain alignment of the tool with respect to the target site according to a second constraint criterion different from the first constraint criterion in response to detection of the one or more system conditions.

[0017] According to an eighth aspect, a method of operating the surgical system of the seventh aspect is provided.

[0018] According to a ninth aspect, there is provided a surgical system including a tool for engaging a target site along a trajectory, a manipulator configured to support the tool, at least one sensor configured to obtain a measured value indicative of a force generated between the target site and the manipulator, and a controller coupled to the manipulator and the at least one sensor, the controller being configured to operate the manipulator to maintain alignment of the tool with respect to the trajectory according to a first constraint criterion, evaluate the obtained measured value indicative of the force, and in response to the evaluation, operate the manipulator to maintain alignment of the tool with respect to the trajectory according to a second constraint criterion different from the first constraint criterion.

[0019] According to a tenth aspect, there is provided a method of operating the surgical system of the ninth aspect.

[0020] According to an eleventh aspect, there is provided a surgical system including a tool for engaging a target site, a manipulator configured to support the tool with respect to the target site, a patient tracker adapted for attachment to the target site, a navigation system configured to track the state of the patient tracker, and a controller coupled to the manipulator and the navigation system, the controller being configured to operate the manipulator to maintain alignment of the tool with respect to the target site according to a first constraint criterion, evaluate the tracked movement of the tool with respect to the movement of the patient tracker based on the tracked state of the patient tracker received from the navigation system, and in response to the evaluation, operate the manipulator to maintain alignment of the tool with respect to the target site according to a second constraint criterion different from the first constraint criterion.

[0021] According to a twelfth aspect, there is provided a method of operating the surgical system of the eleventh aspect.

[0022] According to a 13th aspect, there is provided a surgical system including a tool for engaging a target site, a manipulator configured to support the tool with respect to the target site, a patient tracker adapted for attachment to the target site, a navigation system configured to track the state of the patient tracker, and a controller coupled to the manipulator and the navigation system, the controller being configured to operate the manipulator to restrict the movement of the tool with respect to a virtual boundary associated with the target site according to a first constraint criterion, evaluate the tracked movement of the tool with respect to the movement of the patient tracker based on the tracked state of the patient tracker received from the navigation system, and operate the manipulator to restrict the movement of the tool with respect to the virtual boundary according to a second constraint criterion different from the first constraint criterion in response to the comparison.

[0023] According to a 14th aspect, there is provided a method of operating the surgical system of the 13th aspect.

[0024] Any of the above aspects can be partially or wholly combined. Further, any of the above aspects can be implemented in any of the following implementation forms.

[0025] In one implementation form, the first constraint criterion includes a first number of degrees of freedom by which the movement of the tool is restricted with respect to the target site. In one implementation form, the second constraint criterion includes a second number of degrees of freedom by which the movement of the tool is restricted with respect to the target site. In one implementation form, the second number of degrees of freedom is different from the first number of degrees of freedom. In one implementation form, the controller is further configured to operate the manipulator to maintain alignment of the tool with respect to the target site based on the first number of degrees of freedom in a first mode and to maintain alignment of the tool with respect to the target site based on the second number of degrees of freedom in a second mode.

[0026] In one implementation, the second number of degrees of freedom is less than the first number of degrees of freedom, such that as a result, the controller enables movement of the tool relative to the target site with at least one more degree of freedom in the second mode than in the first mode. In one implementation, the first constraint criterion includes at least one position degree of freedom and at least one orientation degree of freedom. In one implementation, each of the first constraint criterion and the second constraint criterion includes at least one orientation degree of freedom. In one implementation, the first constraint criterion includes at least one more position degree of freedom than the second constraint criterion. In one implementation, the first constraint criterion and the second constraint criterion include at least one common degree of freedom.

[0027] In one implementation, the first constraint criterion includes a first elasticity parameter, and the second constraint criterion includes a second elasticity parameter different from the first elasticity parameter. In one implementation, the controller is further configured to operate the manipulator to maintain alignment of the tool relative to the target site based on the first elasticity parameter in the first mode and based on the second elasticity parameter in the second mode. In one implementation, the controller enables more elastic movement of the tool relative to the target site in the second mode than in the first mode. In one implementation, each of the first elasticity parameter and the second elasticity parameter is associated with elastic movement of the tool relative to the target site in a common degree of freedom.

[0028] In one implementation, the tool defines a tool center point. In one implementation, the controller is configured to operate the manipulator in the first mode to restrict movement of the tool center point away from the target site in accordance with the first constraint criterion.

[0029] In one implementation, the controller is configured to operate the manipulator in the second mode to restrict movement of the tool center point away from the target site in accordance with the second constraint criterion.

[0030] In one implementation, a mode indicator is coupled to the controller. In one implementation, the controller is configured to activate the mode indicator in response to determining that at least one of one or more system conditions meets a predetermined condition, and to notify the user of a change from a first mode of operation of the manipulator to a second mode.

[0031] In one implementation, the controller is configured to operate the manipulator in a first mode to enable movement of the tool relative to the target site in at least one degree of freedom according to a first constraint criterion.

[0032] In one implementation, the controller is configured to operate the manipulator in a second mode to enable movement of the tool relative to the target site in at least one degree of freedom according to a second constraint criterion.

[0033] In one implementation, the controller is further configured to operate the manipulator in a third mode to maintain alignment of the tool with respect to the target site according to a third constraint criterion that is different from both the first constraint criterion and the second constraint criterion. In one implementation, the predetermined condition is further defined as a first predetermined condition. In one implementation, the controller is further configured to change the operation of the manipulator from the second mode to the third mode in response to determining that at least one of one or more system conditions meets a second predetermined condition that is different from the first predetermined condition.

[0034] In one implementation form, the first constraint criterion includes a first number of degrees of freedom by which the movement of the tool is restricted with respect to the target site. In one implementation form, the second constraint criterion includes a second number of degrees of freedom by which the movement of the tool is restricted with respect to the target site. In one implementation form, the third constraint criterion includes a third number of degrees of freedom by which the movement of the tool is restricted with respect to the target site. In one implementation form, the third number of degrees of freedom is different from one or more of the first number of degrees of freedom and the second number of degrees of freedom, and the controller is further configured to operate the manipulator to maintain the alignment of the tool with respect to the target site based on the first number of degrees of freedom in a first mode, based on the second number of degrees of freedom in a second mode, and based on the third number of degrees of freedom in a third mode.

[0035] In one implementation form, the first constraint criterion further includes a first elasticity parameter. In one implementation form, the second constraint criterion further includes a second elasticity parameter. In one implementation form, the third constraint criterion further includes a third elasticity parameter that is different from one or more of the first elasticity parameter and the second elasticity parameter. In one implementation form, the controller is further configured to operate the manipulator to maintain the alignment of the tool with respect to the target site based on the first number of degrees of freedom and based on the first elasticity parameter in a first mode, based on the second number of degrees of freedom and based on the second elasticity parameter in a second mode, and based on the third number of degrees of freedom and based on the third elasticity parameter in a third mode.

[0036] In one implementation form, the third number of degrees of freedom is less than the first number of degrees of freedom. As a result, in the third mode, the controller enables the movement of the tool relative to the target site with at least one more degree of freedom than in the first mode. In one implementation form, the third number of degrees of freedom is less than the second number of degrees of freedom. As a result, in the third mode, the controller enables the movement of the tool relative to the target site with at least one more degree of freedom than in the second mode. In one implementation form, the first constraint criterion and the second constraint criterion each include at least one position degree of freedom and at least one direction degree of freedom. In one implementation form, the first constraint criterion, the second constraint criterion, and the third constraint criterion each include at least one direction degree of freedom. In one implementation form, the first constraint criterion includes at least one more position degree of freedom than the third constraint criterion. In one implementation form, the second constraint criterion includes at least one more position degree of freedom than the third constraint criterion. In one implementation form, the controller enables a more elastic movement of the tool relative to the target site in the second mode than in the first mode. In one implementation form, the controller enables a more elastic movement of the tool relative to the target site in the second mode than in the third mode.

[0037] In one implementation form, the first constraint criterion includes a first elasticity parameter, the second constraint criterion includes a second elasticity parameter, the third constraint criterion includes a third elasticity parameter different from one or more of the first elasticity parameter and the second elasticity parameter, and the controller is further configured to operate the manipulator to maintain the alignment of the tool relative to the target site based on the first elasticity parameter in the first mode, maintain the alignment of the tool relative to the target site based on the second elasticity parameter in the second mode, and maintain the alignment of the tool relative to the target site based on the third elasticity parameter in the third mode.

[0038] In one implementation, the sensing system includes at least one sensor configured to obtain a measurement indicative of a force generated between the target site and the manipulator, and the measurement indicative of the force obtained by the at least one sensor defines at least one of one or more system conditions. In response to the controller determining that the force detected by the at least one sensor satisfies a first predetermined condition, the controller changes the operation of the manipulator from a first mode to a second mode, and in response to the controller determining that the force detected by the at least one sensor satisfies a second predetermined condition, the controller changes the operation of the manipulator from the second mode to a third mode. In one implementation, the first predetermined condition is defined by a first force detected by the at least one sensor, the second predetermined condition is defined by a second force detected by the at least one sensor, and the second force is greater than the first force.

[0039] In one implementation, the patient tracker is adapted for attachment to the target site. In one implementation, the sensing system includes a navigation system configured to track the state of the patient tracker. In one implementation, the tracking state of the patient tracker defines at least one of one or more system conditions, and in response to a determination that the tracking state of the patient tracker satisfies a predetermined condition, the controller is configured to change the operation of the manipulator from a first mode to a second mode. In one implementation, the controller is further configured to compare the tracked movement of the tool with the movement of the patient tracker based on the tracking state received from the navigation system. In one implementation, the tracked movement of the tool defines at least one of one or more system conditions. In one implementation, the predetermined condition is defined based on the tracked movement of the tool corresponding to the tracked state of the patient tracker.

[0040] In one implementation, the sensing system comprises at least one sensor configured to obtain a measurement indicative of a force generated between the target site and the manipulator. In one implementation, the measurement indicative of the force obtained by the at least one sensor defines at least one of one or more system conditions, and the controller is configured to change the operation of the manipulator from a first mode to a second mode in response to determining that the force detected by the at least one sensor satisfies a predetermined condition.

[0041] In one implementation, the controller is further configured to operate the manipulator in a first mode such that as the measurement indicative of the force obtained by the at least one sensor increases towards a predetermined condition, it resists the movement of the tool relative to the target site with an increasing elasticity. In one implementation, the tool includes a guide having a channel formed to receive an impactor assembly and allow limited movement of the impactor assembly relative to the guide, and the impactor assembly has an interface for releasably securing the prosthesis. In one implementation, the manipulator is configured to support the guide along a trajectory relative to the target site while the impactor assembly is received in the channel of the guide and the prosthesis is secured to the impactor assembly. In one implementation, the target site is further defined as an acetabular cup. In one implementation, the at least one sensor is configured to detect a force resulting from a force applied to the impactor assembly to install the prosthesis in the acetabular cup. In one implementation, the controller is further configured to estimate a torque applied to the acetabular cup based on the detected force. In one implementation, the controller is further configured to change the operation of the manipulator from the first mode to the second mode in response to determining that the estimated torque applied to the acetabular cup satisfies a predetermined condition.

[0042] In one implementation form, at least the sensor is further defined as one or more of a force-torque transducer, a joint actuator current sensor, a joint force sensor, a joint torque sensor, and a joint encoder.

[0043] In one implementation form, the first constraint criterion includes a first number of degrees of freedom in which the movement of the tool is restricted with respect to the trajectory. In one implementation form, the second constraint criterion includes a second number of degrees of freedom in which the movement of the tool is restricted with respect to the trajectory. In one implementation form, the second number of degrees of freedom is different from the first number of degrees of freedom. In one implementation form, the controller is further configured to operate the manipulator to maintain the alignment of the tool with respect to the trajectory based on the first number of degrees of freedom in the first mode and based on the second number of degrees of freedom in the second mode.

[0044] In one implementation form, the second number of degrees of freedom is less than the first number of degrees of freedom, such that the controller enables movement of the tool with respect to the trajectory with at least one more degree of freedom in the second mode than in the first mode. In one implementation form, the first constraint criterion includes at least one position degree of freedom and at least one orientation degree of freedom. In one implementation form, each of the first constraint criterion and the second constraint criterion includes at least one orientation degree of freedom. In one implementation form, the first constraint criterion includes at least one more position degree of freedom than the second constraint criterion. In one implementation form, the first constraint criterion and the second constraint criterion include at least one common degree of freedom.

[0045] In one implementation form, the first constraint criterion includes a first elasticity parameter, and the second constraint criterion includes a second elasticity parameter different from the first elasticity parameter. In one implementation form, the controller is further configured to operate the manipulator to maintain the alignment of the tool with respect to the trajectory based on the first elasticity parameter in the first mode and based on the second elasticity parameter in the second mode.

[0046] In one implementation, the controller enables the tool to move more elastically with respect to the trajectory in the second mode than in the first mode. In one implementation, the first elasticity parameter and the second elasticity parameter are each associated with the elastic movement of the tool with respect to the trajectory in a common degree of freedom.

[0047] In one implementation, the controller is further configured to operate the manipulator in the first mode and resist the movement of the tool with respect to the trajectory with an increase in elasticity as the measured value indicating the force acquired by at least the sensor increases towards a predetermined condition.

[0048] In one implementation, the tool defines a tool center point, and the controller is configured to operate the manipulator in the first mode to limit the movement of the tool center point away from the trajectory according to a first constraint criterion. In one implementation, the controller is configured to operate the manipulator in the second mode to enable the movement of the tool center point away from the trajectory according to a second constraint criterion.

[0049] In one implementation, a mode indicator is coupled to the controller, and the controller is configured to activate the mode indicator in response to determining that the measured value indicating the force acquired by at least the sensor satisfies a predetermined condition for communicating to the user a change of the manipulator's operation from the first mode to the second mode.

[0050] In one implementation, the controller is configured to operate the manipulator in the first mode to enable the movement of the tool with respect to the trajectory in at least one degree of freedom according to a first constraint criterion.

[0051] In one implementation, the controller is configured to operate the manipulator in the second mode to enable the movement of the tool with respect to the trajectory in at least one degree of freedom according to a second constraint criterion.

[0052] In one implementation, the controller is further configured to operate the manipulator in a third mode to maintain the alignment of the tool with respect to the trajectory according to a third constraint criterion that is different from both the first constraint criterion and the second constraint criterion. In one implementation, the predetermined condition is further defined as a first predetermined condition. In one implementation, the controller is further configured to change the operation of the manipulator from the second mode to the third mode in response to determining that a measured value indicating a force acquired by at least one sensor satisfies a second predetermined condition that is different from the first predetermined condition. In one implementation, the first predetermined condition is defined by a first force detected by a measured value acquired by at least one sensor, and the second predetermined condition is defined by a second force detected by a measured value acquired from at least one sensor, and the second force is greater than the first force. In one implementation, the first constraint criterion includes a first number of degrees of freedom by which the movement of the tool is restricted with respect to the trajectory, the second constraint criterion includes a second number of degrees of freedom by which the movement of the tool is restricted with respect to the trajectory, the third constraint criterion includes a third number of degrees of freedom by which the movement of the tool is restricted with respect to the trajectory, the third number of degrees of freedom is different from one or more of the first number of degrees of freedom and the second number of degrees of freedom, and the controller is further configured to operate the manipulator to maintain the alignment of the tool with respect to the trajectory based on the first number of degrees of freedom in the first mode, maintain the alignment of the tool with respect to the trajectory based on the second number of degrees of freedom in the second mode, and maintain the alignment of the tool with respect to the trajectory based on the third number of degrees of freedom in the third mode.

[0053] In one implementation, the first constraint criterion further includes a first elasticity parameter, the second constraint criterion further includes a second elasticity parameter, the third constraint criterion further includes a third elasticity parameter different from one or more of the first elasticity parameter and the second elasticity parameter, and the controller further operates the manipulator to maintain the alignment of the tool with respect to the trajectory based on the first number of degrees of freedom and based on the first elasticity parameter in the first mode, maintain the alignment of the tool with respect to the trajectory based on the second number of degrees of freedom and based on the second elasticity parameter in the second mode, and maintain the alignment of the tool with respect to the trajectory based on the third number of degrees of freedom and based on the third elasticity parameter in the third mode.

[0054] In one implementation, the third number of degrees of freedom is less than the first number of degrees of freedom, and as a result, the controller enables movement of the tool with respect to the trajectory with at least one more degree of freedom in the third mode than in the first mode. In one implementation, the third number of degrees of freedom is less than the second number of degrees of freedom, and as a result, the controller enables movement of the tool with respect to the trajectory with at least one more degree of freedom in the third mode than in the second mode.

[0055] In one implementation, the first constraint criterion and the second constraint criterion each include at least one position degree of freedom and at least one direction degree of freedom. In one implementation, the first constraint criterion, the second constraint criterion, and the third constraint criterion each include at least one direction degree of freedom. In one implementation, the first constraint criterion includes at least one more position degree of freedom than the third constraint criterion. In one implementation, the second constraint criterion includes at least one more position degree of freedom than the third constraint criterion. In one implementation, the controller enables more elastic movement of the tool with respect to the trajectory in the second mode than in the first mode. In one implementation, the controller enables more elastic movement of the tool with respect to the trajectory in the second mode than in the third mode.

[0056] In one implementation, the first constraint criterion includes a first elasticity parameter, the second constraint criterion includes a second elasticity parameter, and the third constraint criterion includes a third elasticity parameter that is different from one or more of the first elasticity parameter and the second elasticity parameter. In one implementation, the controller is further configured to operate the manipulator to maintain the alignment of the tool with respect to the trajectory based on the first elasticity parameter in a first mode, maintain the alignment of the tool with respect to the trajectory based on the second elasticity parameter in a second mode, and maintain the alignment of the tool with respect to the trajectory based on the third elasticity parameter in a third mode.

[0057] In one implementation, the patient tracker is adapted for attachment to a target site, the navigation system is configured to track the state of the patient tracker, and the controller is coupled to the navigation system and further configured to define a trajectory based on the tracking state of the patient tracker received from the navigation system.

[0058] In one implementation, the tool includes a guide having a channel formed to receive an impactor assembly and allow limited movement of the impactor assembly relative to the guide, and the impactor assembly has an interface for releasably securing a prosthesis. In one implementation, the manipulator is configured to support the guide with respect to the target site.

[0059] In one implementation, the manipulator is configured to support the guide relative to the target site while the impactor assembly is received in the guide channel and the prosthesis is secured to the impactor assembly, the target site being further defined as an acetabular cup. In one implementation, at least one sensor is configured to obtain a measurement indicative of a force resulting from a force applied to the impactor assembly to install the prosthesis in the acetabular cup. In one implementation, the controller is further configured to estimate a torque applied to the acetabular cup based on the detected force. In one implementation, the controller is further configured to change the operation of the manipulator from a first mode to a second mode in response to determining that the estimated torque applied to the acetabular cup meets a predetermined condition.

[0060] In one implementation, the controller is configured to determine a parameter of a second constraint criterion based on system conditions detected from a sensing system.

[0061] In one implementation, the controller is configured to determine a parameter of a second constraint criterion based on an acquired measurement indicative of a force.

[0062] In one implementation, the controller is configured to determine a parameter of a second constraint criterion based on an evaluated and tracked movement.

[0063] Any of the above implementations can be used in any of the above aspects. Any of the above implementations can be combined, in whole or in part, for any one or more of the above aspects.

[0064] Other features and advantages of the present disclosure will become readily apparent to those of ordinary skill in the art upon reading the following detailed description in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0065]

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Best Mode for Carrying Out the Invention

[0066] Any one or more of the embodiments shown throughout the drawings may be shown schematically and / or in phantom with certain components, structural features, and / or assemblies removed for purposes of illustration.

[0067] Referring now to FIG. 1, a surgical system 100 is shown that includes a robotic manipulator 102 that supports a tool 104. The surgical system 100 is useful for treating an anatomical volume or target site TS of a patient P's body B, such as bone or soft tissue. For this purpose, the manipulator 102 generally includes a base 106, a robotic arm 108, and a coupling 110. The robotic arm 108 is supported by the base 106 and is configured to move, maintain, or otherwise control the position and / or orientation of the coupling 110 relative to the base 106 during use. The coupling 110 is adapted to releasably secure one or more types of tools 104, and the tool 104 generally supports or otherwise includes an instrument 112 that is utilized in connection with various types of surgical procedures in sequence. In some embodiments, the instrument 112 is configured to support, drive, rotate, oscillate, vibrate, and / or otherwise conduct energy to an energy applicator 114 (e.g., drill bit, tap, bar, blade, saw, reamer, etc.) used to perform a treatment at or adjacent to the target site TS. In some embodiments, the instrument 112 may be configured to support, position, align, and / or guide an implantable component 116 (e.g., cup, stem, screw, pin, rod, wire, anchor, prosthesis, etc.) with respect to the target site TS, such as along a trajectory T maintained by the manipulator 102.

[0068] In FIG. 1, patient P is undergoing an exemplary surgical procedure where the target site TS includes the patient's hip joint and a portion of the femur, or is otherwise defined. However, the various types of surgical procedures contemplated by the present disclosure include, but are not limited to, surgical procedures such as partial or total knee or hip replacement surgery, shoulder replacement surgery, spinal surgery, ankle surgery, etc. The surgical procedure may include tissue removal or other forms of treatment (e.g., cutting, drilling, reaming, coagulation, ablation, other in-situ tissue treatment, etc.). In some embodiments, the surgical system 100 may be designed to facilitate cutting of the material to be replaced by implantable components 116 (also referred to as "implants"), such as hip and knee implants including unicompartment, bicompartment, multicompartment, or total knee implants. Some types of implantable components 116 are shown in U.S. Patent No. 9,381,085 entitled "Prosthetic Implant and Method of Implantation," the disclosure of which is hereby incorporated by reference in its entirety. However, as will be understood from the following description, other configurations are contemplated and the surgical system 100 can be utilized in connection with several different surgical procedures and can use various types, styles, and configurations of the manipulator 102, tool 104, instrument 112, energy applicator 114, and / or implantable component 116 without departing from the scope of the present disclosure. Further, the surgical system 100 and techniques disclosed herein can be used to perform other procedures, whether surgical or non-surgical, or can be used in industrial or other applications where robotic systems are utilized.

[0069] The manipulator 102 (also referred to as a "surgical robot") moves the tool 104 relative to the target site TS and relative to the base 106 via the robotic arm 108, and in particular, executes various types of surgical procedures while precisely controlling the movement, and positions the tool 104, the instrument 112, the energy applicator 114, and / or the implantable component 116 to assist medical professionals. As described above, the manipulator 102 generally includes a base 106, a robotic arm 108, and a coupling 110. The base 106 is fixed to the manipulator cart 118, supports the robotic arm 108, and is configured to sequentially move, maintain, or otherwise control the position and / or orientation of the coupling 110 relative to the base 106 during use. For this purpose, the robotic arm 108 shown in FIG. 1 includes a plurality of links 120 and joints J arranged in a serial arm configuration. However, the manipulator 102 can adopt different configurations without departing from the scope of the present disclosure. As a non-limiting example, the manipulator 102 can have a parallel arm configuration, or any other suitable configuration. In some embodiments, two or more manipulators 102 can be utilized in a multi-arm configuration. One exemplary configuration of the robotic arm 108 is described in U.S. Patent No. 9,119,655 entitled "Surgical Manipulator Capable of Controlling a Surgical Instrument in Multiple Modes", the disclosure of which is incorporated herein by reference in its entirety. The robotic arm 108 and other parts of the manipulator 102 can be arranged in several different configurations without departing from the scope of the present disclosure.

[0070] In the example shown in FIG. 1, the manipulator 102 includes a plurality of joint encoders 122 disposed at the joint J to determine the position data of the joint J. Although only one joint encoder 122 is labeled in FIG. 1 for simplicity, the other joint encoders 122 may be similarly shown. In the representative embodiment shown herein, the robotic arm 108 has six joints J1, J2, J3, J4, J5, J6 that implement at least six degrees of freedom (DOF) with respect to the manipulator 102. However, the manipulator 102 may have any suitable number of degrees of freedom, may have any suitable number of joints J, and may have redundant joints J. The manipulator 102 does not require joint encoders 122, but instead or in addition, utilizes motor encoders present on the motors of each joint J. Further, the manipulator 102 does not require rotational joints, but instead or additionally, one or more prismatic joints can be utilized. Any suitable combination of joint types is contemplated.

[0071] Surgical system 100 utilizes various types of trackers (e.g., optical, inertial, and / or ultrasonic sensing devices with multiple degrees of freedom), navigation systems (e.g., machine vision systems, charge-coupled device cameras, tracker sensors, surface scanners, and / or rangefinders), anatomical computer models (e.g., magnetic resonance imaging scans of a patient's anatomical structure), previous data surgical procedures and / or previously performed surgical techniques (e.g., data recorded during steps prior to a surgical procedure), etc., to monitor, track, and / or determine changes in the relative positions and / or orientations of one or more of the manipulator 102, robotic arm 108, tool 104, instrument 112, energy applicator 114, and / or implantable component 116, and various parts of the patient's body B within a common coordinate system. For these purposes, and as schematically shown in FIG. 1, surgical system 100 includes or is otherwise communicable with one or more of a robotic control system 126, a navigation system 128, and a tool control system 130, a control system 124 (also referred to as "controller" 124), which, as will be described in more detail later, cooperates to facilitate positioning, movement, and / or actuation of tool 104 relative to the target site TS and other parts of surgical system 100 via manipulator 102. An exemplary control methodology is described in U.S. Patent No. 10,327,849 entitled "Robotic System and Method for Backdriving the Same", the disclosure of which is hereby incorporated by reference in its entirety.

[0072] Base 106, or another portion of the manipulator 102, generally provides a fixed reference coordinate system for other components of the manipulator 102 and / or other components of the surgical system 100. Generally, the origin of the manipulator coordinate system MNPL is defined with respect to a fixed reference of the base 106. The base 106 can be defined with respect to any suitable portion of the manipulator 102, such as one or more of the links 120. Alternatively, or additionally, the base 106 can be defined with respect to the manipulator cart 118, such as when the manipulator 102 is physically attached to the cart 118. In some embodiments, the base 106 is defined at the intersection of the axis of joint J1 and the axis of joint J2. Thus, although joints J1 and J2 are actually movable components, the intersection of the axes of joints J1 and J2 is a virtual fixed reference pose that provides both a fixed position and a direction reference and does not move relative to the manipulator 102 and / or the manipulator cart 118. In some embodiments, the manipulator 102 can be handheld such that the base 106 is defined by a tool base portion (e.g., a portion that is grasped freehand by the user) for a tool tip (e.g., an end effector) that is movable relative to the base portion. In this embodiment, the base portion has a reference coordinate system that is tracked, and the tool tip has a tool tip coordinate system that is calculated relative to the reference coordinate system (e.g., via motors and / or joint encoders and forward kinematic calculations). Since the pose of the tool tip relative to the path can be determined, the movement of the tool tip can be controlled to follow the path. An example of this type of handheld manipulator 102 is shown in U.S. Patent No. 9,707,043, entitled "Surgical Instrument Including Housing, A Cutting Accessory that Extends from the Housing and Actuators that Establish the Position of the Cutting Accessory Relative to the Housing". The disclosure of which is incorporated herein by reference in its entirety.The above are non-limiting illustrative examples, and other configurations are contemplated by the present disclosure.

[0073] As schematically shown in FIG. 1, the robot control system 126 includes a manipulator controller 132, the navigation system 128 includes a navigation controller 134, and the tool control system 130 includes a tool controller 136. In the illustrated embodiment, the manipulator controller 132, the navigation controller 134, and the tool controller 136 are generally arranged to communicate with each other (e.g., directly or indirectly) via, for example, physical electrical connections (e.g., tethered wire harnesses) and / or one or more types of wireless communication (e.g., WiFi (trademark) networks, Bluetooth (registered trademark), wireless networks, etc.), and / or communicate with other components of the surgical system 100. The manipulator controller 132, the navigation controller 134, and / or the tool controller 136 can be implemented as, or in conjunction with, various arrangements such as computers, processors, control units, etc., and can include individual components or can be integrated (e.g., sharing hardware, software, input, output, etc.). Other configurations are possible.

[0074] The manipulator controller 132, the navigation controller 134, and / or the tool controller 136 can each be implemented as a computer having a processor 138 (e.g., a central processing unit) and / or other processors, a memory 140, and / or storage (not shown), and software is generally loaded as will be described in more detail below. The processor 138 can include one or more processors for controlling the operation of the manipulator 102, the navigation system 128, or the tool 104. The processor 138 can be any type of processor, multiprocessor, and / or multi-core processing system. The manipulator controller 132, the navigation controller 134, and / or the tool controller 136 can additionally or alternatively include one or more microcontrollers, field programmable gate arrays, system on chips, discrete circuits, and / or other suitable hardware, software, or firmware capable of performing the functions described herein. The term processor is not intended to limit any embodiment to a single processor. The robot control system 126, the navigation system 128, and / or the tool control system 130 can also include, define, otherwise employ, a user interface 142 having one or more output devices 144 (e.g., a screen, display, status indicator, etc.) and / or input devices 146 (e.g., a push button, keyboard, mouse, microphone, voice activation device, gesture control device, touch screen, foot pedal, pendant, etc.). Other configurations are contemplated.

[0075] As described above, one or more tools 104 (sometimes referred to as “end effectors”) are releasably attached to the coupling 110 of the manipulator 102, are movable relative to the base 106, and interact with the anatomical structure of the patient P in a particular mode (e.g., the target site TS). The tool 104 can be grasped by a user (e.g., a surgeon). The tool 104 generally includes a mount 148 adapted to be releasably attached to the coupling 110 of the manipulator 102. The mount 148, in some embodiments, supports an instrument 112 that can be configured as a powered surgical device 150 that uses a power generation assembly 152 (e.g., a motor, actuator, gear train, etc.) to drive an attached energy applicator 114 (e.g., via a chuck, coupling, etc.). One exemplary configuration of this type of manipulator 102, tool 104, and instrument 112 is described in U.S. Patent No. 9,119,655, titled “Surgical Manipulator Capable of Controlling a Surgical Instrument in Multiple Modes,” previously incorporated by reference. The manipulator 102, tool 104, and / or instrument 112 can be arranged in alternative configurations. In some embodiments, the tool 104 and / or instrument 112 can be similar to those shown in U.S. Patent No. 9,566,121, titled “End Effector of a Surgical Robotic Manipulator.” The disclosure thereof is incorporated herein by reference in its entirety. In some embodiments, the tool 104 and / or instrument 112 can be similar to those shown in U.S. Patent Application Publication No. 2019 / 0231447A1, titled “End Effectors And Methods For Driving Tools Guided By Surgical Robotic Systems.” The disclosure thereof is incorporated herein by reference in its entirety. Other configurations are contemplated.In some embodiments, and as described in more detail below, the instrument 112 may not be configured as a powered surgical device 150.

[0076] In some embodiments, the energy applicator 114 is designed to contact and remove the patient P's tissue at the target site TS. For this purpose, the energy applicator 114 may include a bar 154 in some embodiments. The bar 154 can be substantially spherical and can include a spherical center, radius, and diameter. Alternatively, the energy applicator 114 can be a drill bit, a saw blade, an ultrasonic vibrating tip, or the like. The tool 104, the instrument 112, and / or the energy applicator 114 can include any geometric features including, but not limited to, a perimeter, a circumference, a radius, a diameter, a width, a length, a volume, an area, a surface / plane, a range of a motion envelope (along any one or more axes), etc. The geometric features can be considered to determine how to position the tool 104 relative to the tissue at the target site TS to perform the desired treatment. In some of the embodiments described herein, the spherical bar 154 having or otherwise defining a tool center point (TCP) is described for purposes of illustration and convenience, but is not intended to limit the tool 104, the instrument 112, and / or the energy applicator 114 to any particular form. In some embodiments described herein, the tool center point TCP is defined by a part of the instrument 112 or the tool 104, rather than the energy applicator 114. Other configurations are contemplated.

[0077] In some embodiments, such as when the instrument 112 is implemented as a powered surgical device 150, the tool 104 can facilitate the operation of the tool 104, such as controlling the power to the power generation assembly 152 (e.g., a rotary motor), controlling the movement of the tool 104, and controlling the irrigation / aspiration of the tool 104, using the tool controller 136. The tool controller 136 can communicate with the manipulator controller 132 and / or other components of the surgical system 100. In some embodiments, the manipulator controller 132 and / or the tool controller 136 can be housed in the manipulator 102 and / or the manipulator cart 118. In some embodiments, the components of the tool controller 136 can be housed in the tool 104. Other configurations are contemplated. The tool control system 130 can also include a user interface 142 with one or more output devices 144 and / or input devices 146, which can be formed as part of the tool 104 and / or implemented by other parts of the surgical system 100 and / or the control system 124 (e.g., the robotic control system 126 and / or the navigation system 128). Other configurations are contemplated.

[0078] The manipulator controller 132 controls the state (position and / or orientation) of the tool 104 (e.g., the tool center point TCP) with respect to a coordinate system such as the manipulator coordinate system MNPL. The manipulator controller 132 can control the (linear or angular) velocity, acceleration, or other derivative of the motion of the tool 104. In one example, the tool center point TCP is a predetermined reference point defined by the energy applicator 114. However, as described above, other components of the tool 104 and / or the instrument 112 can define the tool center point TCP in some embodiments. In any case, the tool center point TCP takes a pose known with respect to other coordinate systems. The pose of the tool center point TCP may be static or may be calculated. In some embodiments, the shape of the energy applicator 114 is known or defined with respect to the TCP coordinate system of the tool center point. The tool center point TCP can be located at the spherical center of the bar 154 of the energy applicator 114 supported or defined by the instrument 112 of the tool 104 such that only one point is tracked. The tool center point TCP can be defined in various ways depending on the configuration of the energy applicator 114, the instrument 112, the tool 104, etc.

[0079] The manipulator 102 can be enabled to determine the pose of the tool center point TCP using the joint encoder 122 (and / or the motor encoder as described above), or any other non-encoder position detection method. The manipulator 102 can determine the tool center point TCP pose using joint J measurements and / or can directly measure the tool center point TCP pose using various techniques. The control of the tool 104 is not limited to the center point. For example, the tool 104 can be represented using any suitable primitive, mesh, etc. Other configurations are contemplated.

[0080] Continuing to refer to FIG. 1, as described above, the surgical system 100 includes, among other things, a navigation system 128 configured to track, monitor, detect, or otherwise sense the movement of various objects such as tool 104, an object (e.g., a part of an anatomical structure, a tracker, etc.), and a pointer 156 used to register a part of the patient's body B (e.g., a bone or other anatomical structure at or adjacent to the target site TS). For this purpose, the navigation system 128 uses a localizer 158 configured to sense the position and / or orientation of a tracker 160 within a localizer coordinate system LCLZ. The navigation controller 134 is arranged to communicate with the localizer 158 and collect position and / or orientation data of each tracker 160 sensed within the field of view of the localizer 158 within the localizer coordinate system LCLZ.

[0081] The localizer 158 can sense the position and / or orientation of multiple trackers 160 to track the corresponding multiple objects within the localizer coordinate system LCLZ. By way of example, as shown in FIG. 1, the tracker 160 can include a pointer tracker 160P coupled to the pointer 156, a manipulator tracker 160M coupled to the base 106 of the manipulator 102, one or more tool trackers 160G, 160I coupled to a part of the tool 104, a first patient tracker 160A coupled to a part of the anatomical structure of the patient P, and a second patient tracker 160B coupled to another part of the anatomical structure of the patient P, as well as additional patient trackers, additional medical and / or surgical tools, trackers for instruments, etc.

[0082] In some embodiments, as shown in FIG. 1, one or more tool trackers 160G, 160I can be respectively coupled to different portions of the tool 104, such as portions configured to move relative to each other, and / or can be firmly attached to a manipulator tracker 160M that is firmly attached to the base 106 of the manipulator 102. By way of non-limiting example, and as described in more detail below, the first tool tracker 160G can be coupled to a mount 148 (or another portion of the tool 104) to move simultaneously with the coupling 110 via the manipulator 102, and the second tool tracker 160I can be coupled to a different portion of the tool 104 that moves relative to the mount 148 and / or the coupling 110 in one or more degrees of freedom. The first tool tracker 160G and the second tool tracker 160I shown in FIG. 1 can be used by the navigation system 128 to readily determine the relative position and / or orientation of different portions of the tool 104 via the localizer 158, although particular embodiments of the present disclosure can be configured to facilitate this determination in other ways (e.g., using one or more sensors). Here, other configurations are contemplated by the present disclosure, and various combinations of trackers 160, sensors, predetermined geometric relationships, etc. can be utilized to track particular objects or otherwise associate them with objects being tracked.

[0083] Continuing to refer to FIG. 1, the first patient tracker 160A is firmly fixed to one bone of the patient's body B at or adjacent to the target site TS (e.g., the pelvis near the acetabulum), and the second patient tracker 160B is firmly fixed to another bone (e.g., a portion of the femur). Although not shown in detail, the patient trackers 160A, 160B can be coupled to several different bones within the patient's body B in various ways, such as by threaded engagement, clamping, or other techniques. Similarly, the first tool tracker 160G and / or the second tool tracker 160I can be fixed to portions of the tool 104 in various ways, such as by integration during manufacture or by releasable attachment before or during a surgical procedure. The various trackers 160 can be firmly attached to different types of tracked objects (e.g., individual bones, tools, pointers, etc.) in several different ways. For example, the tracker 160 can be firmly fixed, flexibly connected (optical fiber), or not physically connected at all (ultrasonic), as long as there is an appropriate (e.g., complementary) method for determining the relationship (e.g., measurement) of each tracker 160 to the associated object or anatomical structure.

[0084] The position and / or orientation of the tracker 160 relative to the object or anatomical structure to which the tracker 160 is attached can be determined by using known alignment techniques. For example, determining the pose of the patient trackers 160A, 160B relative to the portion of the patient's body B to which they are attached can be accomplished by various forms of point-based alignment, such as where the distal tip of the pointer 156 is used to engage (e.g., touch) a particular portion of a bone or where the localizer 158 is used to engage several portions of the bone for surface-based alignment when monitoring the position and orientation of the pointer tracker 160P. The poses of the patient trackers 160A, 160B can then be correlated to the patient's anatomical structures (e.g., each of the femur and acetabulum) using conventional alignment techniques.

[0085] Also, other types of alignment are possible, such as using patient trackers 160A, 160B that sandwich the bone and include a tactile sensor (not shown) that determines the shape of the bone clamped by the clamp. Next, the shape of the bone can be matched to a three-dimensional model of the bone for alignment. The known relationship between the tactile sensor and the markers 162 on the patient trackers 160A, 160B can be input to the navigation controller 134 or otherwise be known (e.g., stored in the memory 140). Based on this known relationship, the position of the markers 162 relative to the patient's anatomical form can be determined. The position and / or orientation data can be collected, determined, or otherwise processed by the navigation controller 134 using several different alignment / navigation techniques to determine the coordinates of each tracker 160 within the localizer coordinate system LCLZ or another suitable coordinate system. These coordinates are transmitted to other parts of the control system 124, such as the robot control system 126, to facilitate the articulation of the manipulator 102 and / or to assist the surgeon in performing the surgical procedure, as will be described in more detail below.

[0086] In a representative embodiment shown herein, the manipulator controller 132 and the tool controller 136 are operably attached to the base 106 of the manipulator 102, and the navigation controller 134 and the localizer 158 are supported on a mobile cart 164 that is movable relative to the base 106 of the manipulator 102. The mobile cart 164 may also support a user interface 142 to facilitate the operation of the surgical system 100 by displaying information to and / or receiving information from a surgeon or another user. Although shown as part of the navigation system 128 in the representative embodiment shown in FIG. 1, the user interface 142 may form part of a control system 124 such as the robot control system 126 and / or the tool control system 130, or alternatively may communicate with other parts. For this purpose, the user interface 142 may be arranged to communicate with the navigation controller 134, the manipulator controller 132, and / or the tool controller 136, and may similarly include one or more output devices 144 (e.g., monitors, indicators, display screens, etc.), presenting information to a surgeon or other user (e.g., images, videos, data, graphics, navigable menus, etc.), and one or more input devices 146 (e.g., physical or virtual input controls, buttons, touchscreens, keyboards, mice, gesture or voice-based input devices, etc.). One type of mobile cart 164 and user interface 142 utilized in this type of navigation system 128 are described in U.S. Patent No. 7,725,162 entitled "Surgery System", the disclosure of which is hereby incorporated by reference in its entirety.

[0087] The base 106 of the mobile cart 164 and the manipulator 102 can be arranged relative to each other and also relative to the patient's body B, so that one or more parts of the surgical system 100 generally convert the coordinates of each tracker 160 sensed via the localizer 158 from the localizer coordinate system LCLZ to the manipulator coordinate system MNPL (or to another coordinate system), or vice versa, and the articulation movement of the manipulator 102 can be performed based at least in part on the relative position and / or orientation of a particular tracker 160 within a common coordinate system (e.g., the manipulator coordinate system MNPL, the localizer coordinate system LCLZ, or another common coordinate system). The coordinates within the localizer coordinate system LCLZ can be converted to the coordinates within the manipulator coordinate system MNPL (or another coordinate system) using various transformation techniques, and vice versa. An example of the conversion or transformation of data between coordinate systems is described in U.S. Patent No. 8,675,939 entitled "Registration of Anatomical Data Sets", the disclosure of which is hereby incorporated by reference in its entirety.

[0088] In the illustrated embodiment, the localizer 158 is an optical localizer and includes a camera unit 166 with one or more optical sensors 168, and in some embodiments, a video camera 170. The localizer 158 may also include a navigation controller 134 or, alternatively, a localizer controller (not shown) that forms part of the navigation system 128. The navigation system 128 uses the optical sensors 168 of the camera unit 166 to sense the position and / or orientation of the tracker 160 within the localizer coordinate system LCLZ. In the representative embodiments shown herein, each of the trackers 160 uses a plurality of markers 162 (see FIG. 2) that can be sensed by the optical sensors 168 of the camera unit 166. An example of this type of navigation system 128 is described in U.S. Patent No. 9,008,757, titled "Navigation System Including Optical and Non-Optical Sensors," the disclosure of which is hereby incorporated by reference in its entirety. In some embodiments, the markers 162 are active markers (e.g., light-emitting diodes "LEDs") that emit light that can be sensed by the localizer 158. In some embodiments, the tracker 160 can use passive markers (e.g., reflectors) that reflect light emitted from the localizer 158 or another light source. Although one embodiment of the navigation system 128 is shown throughout the drawings, the navigation system 128 can have any suitable configuration for monitoring the tracker 160 and can be of various types and configurations, as will be understood from the following description. For example, the navigation system 128 can include multiple localizers 158 and / or trackers 160 of the same or different types.

[0089] In some embodiments, navigation system 128 and / or localizer 158 are radio frequency (RF)-based. For example, navigation system 128 may comprise an RF transceiver coupled to navigation controller 134 and / or another computing device, controller, etc. Here, tracker 160 may include an RF emitter or transponder, which may be passive or may be energized actively. The RF transceiver transmits an RF tracking signal, and the RF emitter responds with an RF signal such that the tracked status is communicated (or interpreted) to navigation controller 134. The RF signal may be of any suitable frequency. The RF transceiver can be placed at any suitable location to effectively use the RF signal to track an object. Further, embodiments of RF-based navigation systems may have a different structural configuration than the active marker-based navigation system 128 shown herein.

[0090] In some embodiments, navigation system 128 and / or localizer 158 are electromagnetic (EM)-based. For example, navigation system 128 may comprise an EM transceiver coupled to navigation controller 134 and / or another computing device, controller, etc. Here, tracker 160 may include EM components (e.g., various types of magnetic trackers, electromagnetic trackers, inductive trackers, etc.) attached thereto, which may be passive or may be energized actively. The EM transceiver generates an EM field, and the EM component responds with an EM signal such that the tracked status is communicated (or interpreted) to navigation controller 134. Navigation controller 134 can analyze the received EM signal and associate a relative status therewith. Again, embodiments of EM-based navigation systems may have a different structural configuration than the active marker-based navigation system 128 shown herein.

[0091] In some embodiments, the navigation system 128 and / or the localizer 158 can be based on one or more types of imaging systems that do not necessarily require fixing a tracker 160 to an object to determine associated position data. For example, an ultrasound-based imaging system can be provided to facilitate acquisition of ultrasound images (e.g., specific known structural features of a tracked object, markers or stickers fixed to the tracked object, etc.), and the tracked state (e.g., position, orientation, etc.) can be communicated to (or interpreted by) the navigation controller 134 based on the ultrasound images. The ultrasound images can be three-dimensional, two-dimensional, or a combination thereof. The navigation controller 134 can process the ultrasound images in substantially real time to determine the tracked state. The ultrasound imaging device can have any suitable configuration and can be different from the camera unit 166 as shown in FIG. 1. As a further example, a fluoroscopy-based imaging system can be provided to facilitate acquisition of X-ray images of radiopaque markers (e.g., stickers, tags, etc. having known structural features attached to the tracked object), such that the tracked state is communicated to (or interpreted by) the navigation controller 134 based on the X-ray images. The navigation controller 134 can process the X-ray images in substantially real time to determine the tracked state. Similarly, other types of optical-based imaging systems can be provided to facilitate acquisition of digital images, videos, etc. of specific known objects (e.g., based on comparison with a virtual representation of the tracked object or its structural components or features) and / or markers (e.g., stickers, tags, etc. affixed to the object being tracked) (e.g., via a charge-coupled device "CCD" sensor such as the video camera 170), and the tracked state is communicated to (or interpreted by) the navigation controller 134 based on the digital images. The navigation controller 134 can process the digital images in substantially real time to determine the tracked state.

[0092] Accordingly, various types of imaging systems, including multiple imaging systems of the same or different types, can form part of the navigation system 128 without departing from the scope of the present disclosure. The navigation system 128 and / or the localizer 158 may have other suitable components or structures not specifically described herein. For example, the navigation system 128 can utilize inertial tracking only, or any combination of tracking techniques, and additionally or alternatively can include fiber-optic based tracking, machine vision tracking, and the like. Further, any of the techniques, methods, and / or components associated with the navigation system 128 shown in FIG. 1 can be implemented in several different ways, and other configurations are contemplated by the present disclosure.

[0093] In some embodiments, the surgical system 100 can present a virtual representation of the relative position and orientation of a tracked object to a surgeon or other user of the surgical system 100, for example, in a graphical representation of an image and / or anatomical structure of the patient's body B, tool 104, instrument 112, energy applicator 114, etc. presented on one or more output devices 144 (e.g., a display screen). The manipulator controller 132 and / or the navigation controller 134 can also use the user interface 142 to display instructions or request information so that a surgeon or other user can interact with the robotic control system 126 (e.g., using a graphical user interface GUI) and facilitate the articulation of the manipulator 102. Other configurations are contemplated.

[0094] As described above, the localizer 158 tracks the tracker 160 and determines the respective state of the tracker 160 corresponding to the state of the object attached to each. The localizer 158 can perform known triangulation techniques to determine the state of the tracker 160 and the associated object. The localizer 158 provides the state of the tracker 160 to the navigation controller 134. In some embodiments, the navigation controller 134 determines the state of the tracker 160 and communicates it to the manipulator controller 132. As used herein, the state of an object includes, but is not limited to, data defining the position and / or orientation of the object being tracked, or the equivalent / derivative of the position and / or orientation. For example, the state can be the pose of the object and can include linear velocity data, and / or angular velocity data, among others. Other configurations are contemplated.

[0095] Referring to FIG. 2, the surgical system 100 generally includes a control system 124, which can include, among other components, a manipulator controller 132, a navigation controller 134, a tool controller 136, and / or the robotic control system 126, navigation system 128, and / or tool control system 130 described above, or can be defined as such. The control system 124 can also include one or more software modules shown in FIG. 3. The software module can be the manipulator controller 132, the navigation controller 134, the tool controller 136, or any combination thereof, and can be part of one or more programs that operate to process data used to facilitate or otherwise assist in the control of the surgical system 100. The software program and / or module includes computer-readable instructions stored in a non-transitory memory 140 on the manipulator controller 132, navigation controller 134, tool controller 136, or a combination thereof, and executed by one or more processors 138 of the controllers 136, 132, 134.

[0096] The memory 140 can be of any suitable configuration, such as a random access memory (RAM), non-volatile memory, etc., and can be executed locally or remotely (e.g., a database, a server, etc.). Further, a software module for displaying and / or communicating with the user a prompt can form part of a module or a program and can include instructions stored in the memory 140 on the manipulator controller 132, the navigation controller 134, the tool controller 136, or any combination thereof. The user can interact with any input device 146 and / or output device 144 of any user interface 142 (e.g., the user interface 142 of the navigation system 128 shown in FIG. 1) to communicate with the software module and / or program. The control system 124 can also include other software or modules executable on each device from the user interface 142 (e.g., a graphical user interface GUI), or the manipulator controller 132, the navigation controller 134, and / or the tool controller 136 (e.g., a portable electronic device such as a tablet computer). Other configurations are contemplated.

[0097] The control system 124 can include any suitable configuration of input, output, and processing devices suitable for performing the functions and methods described herein. The surgical system 100 can include the manipulator controller 132, the navigation controller 134, or the tool controller 136, or any combination thereof, or only a portion of these controllers, or additional controllers, any of which can form a part of the control system 124 as described above. The controllers 132, 134, 136 can communicate via a wired bus, a communication network, wireless communication, or other means, as shown in FIG. 2. The control system 124 can include one or more microcontrollers, field programmable gate arrays, system-on-chips, discrete circuits, sensors, displays, user interfaces, indicators, and / or other suitable hardware, software, or firmware capable of performing the functions described herein. Other configurations are contemplated.

[0098] Referring to FIG. 3, in some embodiments, the software used by the control system 124 may include a boundary generator 172. As shown in FIG. 4, the boundary generator 172 is a software program or module that generates a virtual boundary 174 for restricting the movement and / or operation of the tool 104. The virtual boundary 174 can be one-dimensional, two-dimensional, or three-dimensional and can include other shapes including points, lines, axes, orbits, planes, or complex geometric shapes. In some embodiments, the virtual boundary 174 is a surface defined by a triangular mesh. Such a virtual boundary 174 may also be referred to as a virtual object. The virtual boundary 174 may be defined with respect to an anatomical model AM such as a three-dimensional bone model. The anatomical model AM is associated with the actual anatomical structure of the patient P based on an anatomical model AM that is mapped to the anatomical structure of the patient P through alignment or other processes. In the example of FIG. 4, the virtual boundary 174 includes a substantially spherical mesh that substantially surrounds an acetabulum with an inlet portion (e.g., an opening) that provides access to the acetabulum. The inlet portion is funnel-shaped or conical. In this representative embodiment, the virtual boundary 174 is associated with a three-dimensional model of the acetabulum of the pelvis.

[0099] The anatomical model AM and the associated virtual boundary 174 are aligned with one or more patient trackers 160A, 160B. Thus, the anatomical model AM (and the associated actual anatomical structure of patient P) and the virtual boundary 174 fixed to the anatomical model AM can be tracked by the patient trackers 160A, 160B. The virtual boundary 174 can be implant-specific (e.g., defined based on the size, shape, volume, etc. of the implantable component 116) and / or patient-specific (e.g., defined based on the anatomical structure of patient P). The virtual boundary 174 can be a boundary created preoperatively, intraoperatively, or a combination thereof. In other words, the virtual boundary 174 can be defined before the surgical procedure begins, during the surgical procedure (including during tissue removal), or a combination thereof. In any case, the control system 124 obtains the virtual boundary 174 by storing / searching for the virtual boundary 174 in / from the memory 140, obtaining the virtual boundary 174 from the memory 140, creating the virtual boundary 174 preoperatively, creating the virtual boundary 174 intraoperatively, etc.

[0100] The manipulator controller 132 and / or the navigation controller 134 can track the state of the tool 104 relative to the virtual boundary 174. In some embodiments, the state of the tool center point TCP is measured relative to the virtual boundary 174 for the purpose of determining the haptic forces applied to the virtual rigid body VRB model via the virtual simulation VS so that the tool 104 remains in the desired positional relationship (e.g., does not move beyond them) relative to the virtual boundary 174. The results of the virtual simulation VS are commanded to the manipulator 102. The control system 124 (e.g., the manipulator controller 132 of the robotic control system 126) controls / positions the manipulator 102 to emulate the way a physical handpiece would respond in the presence of a physical boundary / barrier. The boundary generator 172 can be implemented in the manipulator controller 132. Alternatively, the boundary generator 172 can be implemented in other components such as the navigation controller 134, or other parts of the control system 124. Other configurations are contemplated.

[0101] Referring to FIGS. 3 and 5, the path generator 176 is another software program or module that can be executed by the control system 124. In some embodiments, the path generator 176 is executed by the manipulator controller 132. The path generator 176 generates a tool path TP for the tool 104 to traverse. For example, to remove a section of the anatomical structure of the patient P at the target site TS to receive the implantable component 116. The tool path TP can include a plurality of path segments PS or can include a single path segment PS. The path segment PS can be a straight line segment, a curved line segment, a combination thereof, etc. The tool path TP can also be defined with respect to the anatomical model AM. The tool path TP can be implant specific (e.g., defined based on the size, shape, volume, etc. of the implantable component 116) and / or patient specific (e.g., defined based on the anatomical structure of the patient P). Other configurations are contemplated.

[0102] In some embodiments described herein, the tool path TP is defined as a tissue removal path adjacent to the target site TS. However, in some embodiments, the tool path TP can be used for treatments other than tissue removal. An example of a tissue removal path described herein includes a milling path MP. The term "milling path" generally refers to a path of the tool 104 near the target site TS for milling an anatomical structure, and it should be understood that it is not intended to require the tool 104 to be operable to mill the entire anatomical structure over the entire duration of the path. For example, the milling path MP can include sections or segments where the tool 104 moves from one location to another without milling. Further, other forms of tissue removal along the milling path MP, such as tissue resection, can be used. The milling path MP can be a pre-specified path created preoperatively, intraoperatively, or a combination thereof. In other words, the milling path MP can be defined before the surgical procedure begins, during the surgical procedure (including during tissue removal), or a combination thereof. In any case, the control system 124 can obtain the milling path MP by storing / searching for the milling path MP in the memory 140, retrieving the milling path MP from the memory 140, creating the milling path MP preoperatively, creating the milling path MP intraoperatively, etc. The milling path MP can have any suitable shape, or a combination of shapes such as circular, spiral / plug removal, linear, curved, combinations of those shapes, etc. Other configurations are contemplated.

[0103] An example of a system and method for generating the virtual boundary 174 and / or the milling path MP is described in U.S. Patent No. 9,119,655, titled "Surgical Manipulator Capable of Controlling a Surgical Instrument in Multiple Modes", previously referenced. Further examples are described in U.S. Patent No. 8,010,180, titled "Haptic Guidance System and Method" and U.S. Patent No. 7,831,292, titled "Guidance System and Method for Surgical Procedures with Improved Feedback", the disclosures of which are each incorporated herein by reference in their entirety. In some embodiments, the virtual boundary 174 and / or the milling path MP can be generated offline, rather than by the manipulator controller 132, the navigation controller 134, or another component of the surgical system 100. The virtual boundary 174 and / or the milling path MP can then be utilized by the manipulator controller 132 at runtime.

[0104] Returning to FIG. 3, another software program or module that can be executed by the manipulator controller 132 and / or the navigation controller 134 is shown for performing the motion control 178. The motion control 178 is a process that calculates data indicating the next commanded position and / or orientation (e.g., pose) of the tool 104. Although only the position or orientation of the tool center point TCP may be output from the motion control 178, the position and orientation of the tool center point TCP may also be output from the motion control 178. In some embodiments, the outputs from the boundary generator 172, the path generator 176, and the sensor 180 (e.g., a six-degree-of-freedom DOF force / torque transducer) can be supplied as inputs to the motion control 178 to determine the next commanded position / orientation of the tool 104. The motion control 178 can process these inputs along with one or more virtual constraints VC, as will be described in more detail below, to determine the commanded pose CP.

[0105] Continuing to refer to FIG. 3, another software program or module that may be executed by the manipulator controller 132 and / or the navigation controller 134 is shown for performing motion control 182. One aspect of the motion control 182 is the control of the manipulator 102. The motion control 182 receives data from the motion control 178 that defines the next commanded pose CP. Based on this data, the motion control 182 determines the next position of the joint angle of the joint J of the robot arm 108 of the manipulator 102 (e.g., via inverse kinematics and Jacobian calculations), so that the manipulator 102 can place the tool 104 as commanded by the motion control 178 (e.g., at the commanded pose CP). In other words, the motion control 182 processes the commanded pose CP, which may be defined in Cartesian space, into the joint angles of the manipulator 102, and as a result, the manipulator controller 132 can command the joint motors, depending on the situation, to move the joint J of the manipulator 102 to the commanded joint angles corresponding to the commanded pose CP of the tool 104. In some embodiments, the motion control 182 adjusts the joint angle of each joint J of the robot arm 108 and continuously adjusts the torque output by each joint motor to ensure as precisely as possible that the associated joint J is driven to the commanded joint angle by the joint motor.

[0106] The boundary generator 172, the path generator 176, the motion control 178, and the movement control 182 can be subsets (e.g., modules) of a software program 184. Alternatively, each can be a software program that operates separately and / or independently, or in any combination thereof. The term "software program" is used herein to describe computer-executable instructions configured to perform the various functions of the described technical solution. For simplicity, the term "software program" is intended to encompass at least any one or more of the boundary generator 172, the path generator 176, the motion control 178, and / or the movement control 182. The software program 184 can be implemented by the manipulator controller 132, the navigation controller 134, or any combination thereof, or can be implemented in any suitable manner by the control system 124.

[0107] In some embodiments, the clinical application 186 can be provided to facilitate user interaction and coordinate a surgical workflow including preoperative planning, implant placement, alignment, visualization of bone machining, postoperative evaluation of implant fit, etc. The clinical application 186 can be configured to receive input data from the input device 146, output data to the output device 144 (e.g., display, screen, monitor, etc.), or otherwise interact with the user interface 142, and may include or form part of a graphical user interface GUI. The clinical application 186 can be executed on its own separate processor or can be executed together with the navigation controller 134, the manipulator controller 132, and / or the tool controller 136, or any other suitable part of the control system 124.

[0108] In some embodiments, clinical application 186 interfaces with boundary generator 172 and / or path generator 176 after the implant placement has been set by the user, and then transmits the virtual boundary 174 and / or tool path TP returned by the boundary generator 172 and / or path generator 176 to manipulator controller 132 for execution. Here, manipulator controller 132 executes the tool path TP as described herein. Manipulator controller 132 can further create certain segments (e.g., retraction segments) when starting or resuming machining and smoothly returning to the generated tool path TP. Manipulator controller 132 can also process the virtual boundary 174 to generate a corresponding virtual constraint VC, as described in more detail below.

[0109] Surgical system 100 can be operated in a manual mode as described in U.S. Patent No. 9,119,655, titled "Surgical Manipulator Capable of Controlling a Surgical Instrument in Multiple Modes" previously referenced. Here, the user gives instructions manually, and manipulator 102 executes the movement of tool 104 and its energy applicator 114 at the surgical site. The user (e.g., a surgeon) physically contacts tool 104 to cause the movement of tool 104 in the manual mode. In some embodiments, manipulator 102 monitors the force and torque applied to tool 104 by the user to position tool 104. For this purpose, surgical system 100 can use a sensor 180 (e.g., a DOF force / torque transducer of multiple degrees of freedom) that detects and measures the force and torque applied to tool 104 by the user and generates corresponding inputs (e.g., one or more corresponding input / output signals) used by control system 124. The force and torque applied by the user at least partially define the external force Fext used to determine how to move tool 104 in the manual mode (or other modes). The external force Fext can include other forces and torques other than the force applied by the user, such as gravity compensation force, backdrive force, etc., as described in U.S. Patent No. 9,119,655, titled "Surgical Manipulator Capable of Controlling a Surgical Instrument in Multiple Modes" as previously referenced. Thus, the force and torque applied by the user at least partially define the external force Fext and, in some cases, can completely define the external force Fext that affects the overall movement of tool 104 in the manual mode and / or other modes described in more detail below.

[0110] Sensor 180 may comprise a six-degree-of-freedom (DOF) force / torque transducer arranged to detect forces and / or torques (e.g., forces applied to tool 104 by a user) that occur between manipulator 102 and target site TS. For illustration purposes, sensor 180 is generally shown adjacent to or as part of coupling 110 of manipulator 102 (e.g., coupled to joint J6 of robotic arm 108). However, other configurations and arrangements are possible. Manipulator controller 132, navigation controller 134, tool controller 136, and / or other components of surgical system 100 can receive signals (e.g., as inputs) from sensor 180. In response to the forces and torques applied by the user, manipulator 102 moves tool 104 in a manner that emulates the movement that would have occurred based on the forces and torques applied by the user. The movement of tool 104 in manual mode can also be constrained in relation to virtual boundary 174 generated by boundary generator 172. In some embodiments, measurements obtained by sensor 180 are transformed from the sensor coordinate system SN of sensor 180 to another coordinate system, such as virtual mass coordinate system VM, in which, as described below, virtual simulation VS is performed on the virtual rigid body VRB model of tool 104, thereby virtually applying forces and torques to virtual rigid body VRB in virtual simulation VS to ultimately determine how these forces and torques (among other inputs) affect the movement of virtual rigid body VRB.

[0111] Surgical system 100 can also operate in a semi-autonomous mode where the manipulator 102 moves the tool 104 in an automated manner along the milling path MP, such as by operating the active joint J of the manipulator 102 to move the tool 104 without requiring force / torque from the user. Examples of operation in the semi-autonomous mode are also described in U.S. Patent No. 9,119,655 entitled "Surgical Manipulator Capable of Controlling a Surgical Instrument in Multiple Modes" previously referenced. In some embodiments, when the manipulator 102 operates in the semi-autonomous mode, the manipulator 102 can move the tool 104 without user assistance. Here, "without user assistance" can mean that the user does not physically contact the tool 104 or the robotic arm 108 and does not move the tool 104. Instead, the user can use some form of remote control (e.g., a pendant, not shown) to control the start and stop of the movement. For example, the user can start the movement of the tool 104 by pressing and holding a button on the remote control and stop the movement of the tool 104 by releasing the button. An example of this type of remote control embodied in a user pendant is described in U.S. Patent No. 10,117,713 entitled "Robotic Systems and Methods for Controlling a Tool Removing Material from Workpiece", the disclosure of which is hereby incorporated by reference in its entirety. Other configurations are contemplated.

[0112] In the manual mode, it may be difficult for the user to move the tool 104 from the current state SC to the target state ST (e.g., to the target position PT, the target orientation OT, or the target pose). Moving the tool 104 to a specific target state ST may be desirable for any number of reasons, such as aligning the tool 104 in a specific trajectory / plane, etc., for machining of the tissue to receive the implantable component 116, such as placing the tool 104 at a desired proximity to the milling path MP. However, it may be difficult for the user to place the tool 104 with sufficient accuracy. This can be particularly difficult when the anatomical structure of the patient P is partially obscured from the user's view by soft tissue, body fluids, etc. Here, the surgical system 100 can switch from the manual mode to the semi-autonomous mode as described in U.S. Patent No. 9,119,655 entitled "Surgical Manipulator Capable of Controlling a Surgical Instrument in Multiple Modes" previously referenced. Thus, to place the tool 104 in the target state ST, the manipulator 102 can autonomously move the tool 104 from the current state SC to the target state ST.

[0113] If the user desires to achieve control of the tool 104 while maintaining manual contact with the tool 104 and moving toward the target state ST, the surgical system 100 can also operate in an inductive haptic mode. The inductive haptic mode can be used to assist in guiding the user to place the tool 104 in the target state ST (attraction), or otherwise, or to guide the user away from the target state (repulsion). In the inductive haptic mode, aspects of control used in both the manual mode and the semi-autonomous mode are utilized. For example, the forces and torques applied by the user are still detected by the sensor 180 and supplied to the virtual simulation VS to determine an external force Fext that at least partially affects the overall movement of the tool 104. Further, in the inductive haptic mode, the surgical system 100 generates a virtual attraction (or repulsion) force VF (or torque) embodied in the virtual constraint VC force Fc, which is supplied to the virtual simulation VS along with the external force Fext. The inductive haptic mode can be used to move the tool 104 away from the target state ST (repulsive haptic), and / or to attract the tool 104 to the target state ST (attractive haptic).

[0114] The virtual attraction VF can be virtually applied to the virtual rigid body VRB in the virtual simulation VS and includes forces and / or torques adapted to attract or otherwise prompt the tool 104 towards the target state ST. The virtual attraction VF affects the overall movement of the tool 104 by providing the user with haptic feedback indicating how the tool 104 should be moved to reach the target state ST. More specifically, in the virtual simulation VS, the forces and / or torques associated with the virtual attraction VF can nullify the effects of the forces and / or torques of the external force Fext (and / or other forces and / or torques), such that the tool 104 is ultimately moved in a way that provides the user with a haptic interaction effect, which indicates the direction / rotation in which the tool 104 needs to be moved to reach the target state ST. Thus, the guided haptic mode depends on manual operation to move the tool 104, but such movement does not merely emulate the movement that would occur based on the forces and torques applied by the user, but actively controls to guide the user towards the target state ST. Therefore, the guided haptic mode enables direct user engagement with the tool 104 while providing the advantages associated with autonomous (or semi-autonomous) movement of the tool 104.

[0115] In the induced tactile mode, the tool 104 is effectively attracted to the target state ST to provide the user with tactile interaction effects. These effects are generated in one or more degrees of freedom DOF to be able to attract the tool 104 to the target state ST. Thus, the target state ST can be defined such that the tool 104 is attracted with only one degree of freedom DOF, or can be defined such that the tool 104 is attracted with two or more degrees of freedom DOF. Thus, the target state ST can include a target position PT, a target orientation OT, or both (e.g., a target pose TP) defined in the target coordinate system TF. The target position PT can include one or more position components (e.g., an x position XP, a y position YP, and / or a z position ZP) with respect to the x, y, and / or z axes of the target coordinate system TF. In some cases, the target position PT can be represented as the origin of the target coordinate system TF. Similarly, the target orientation OT can include one or more orientation components (e.g., an x orientation XO, a y orientation YO, and / or a z orientation ZO) with respect to the x, y, and / or z axes of the target coordinate system TF. The x position XP, the y position YP, the z position ZP, the x orientation XO, the y orientation YO, and the z orientation ZO each represent their respective degrees of freedom DOF (e.g., of the coordinate system). In some cases, the target orientation OT can be represented as the directions of the x, y, z axes of the target coordinate system TF. The term "target pose" TP means a combination of one or more position components XP, YP, ZP and one or more orientation components XO, YO, ZO. In some cases, the target pose TP can include the target position PT and the target orientation OT in all six degrees of freedom DOF of the target coordinate system TF. In some cases, the target position PT and / or the target orientation OT may also be referred to as the starting position and / or the starting orientation.

[0116] The target coordinate system TF can be any coordinate system in which the target state ST is defined, and the target state ST can be converted to any other coordinate system that is desired for monitoring the current state SC of the tool 104 relative to the target state ST of the tool 104. The target state ST can be tracked, for example, in a tracker coordinate system, a localizer coordinate system LCLZ, a manipulator coordinate system MNPL, a virtual mass coordinate system VM, a tool center point TCP coordinate system, and the like. The target state ST can be defined with respect to an anatomical model AM of the patient P and can be fixed with respect to the anatomical structure of the patient P in an anatomical model coordinate system, an anatomical tracker coordinate system (e.g., tracked by one or more patient trackers 160A, 160B), and the like. The current state SC of the tool 104 can be defined with respect to an induced coordinate system GF. The induced coordinate system GF can be linked to another coordinate system, or the current state SC can be converted to any induced coordinate system GF to enable tracking of the current state SC relative to the target state ST. For example, the current state SC can be tracked in a tracker coordinate system, a localizer coordinate system LCLZ, a manipulator coordinate system MNPL, a virtual mass coordinate system VM, a tool center point TCP coordinate system, and the like. In some embodiments, the current state SC of the tool 104 can be initially defined by a tool center point TCP coordinate system (e.g., the TCP coordinate system and the induced coordinate system GF are shown to be the same for illustrative purposes), and the target state ST can initially be defined with respect to an anatomical model coordinate system, but both the guide coordinate system GF and the target coordinate system TF can be converted to a common coordinate system for tracking purposes. The target state ST can be defined preoperatively, intraoperatively, or both. Various aspects such as intraoperative planning, anatomical models, etc. are described in U.S. Patent Application Publication No. US2018 / 0333207A1, entitled "Surgical Systems and Methods for Facilitating Ad-hoc Intraoperative Planning of Surgical Procedures". This disclosure is incorporated herein by reference in its entirety. Other configurations are contemplated.

[0117] The control system 124 uses virtual constraints VC that are defined to generate a virtual attraction force VF (e.g., force and / or torque) used in a virtual simulation VS that pulls the tool 104 to the target state ST. These virtual constraints VC are referred to herein as guide constraints GC. The guide constraints GC are ultimately defined to affect the movement of the tool 104 to the target state ST, such that the user is provided with one or more of the haptic interaction effects described above. Generally, the virtual constraints VC are restrictions on the movement of a rigid body that are considered by the control system 124 along with other movement-related information to determine how to command the manipulator 102 to move the tool 104. As will be further described below, the guide constraints GC have configurable spring parameters PS and damping parameters PD so that the guide constraints GC do not become infinitely stiff. More specifically, in some versions, the guide constraints GC are defined as "soft constraints" so as not to impede movements that violate them, such as movements resulting from forces and torques applied by the user in a direction opposite to the target state ST. Thus, in the guided haptic mode or other modes, the user can still violate the guide constraints GC, and the guide constraints GC can still generate an attraction force and torque that oppose the user (e.g., haptic interaction effects) that the user feels and affect the movement of the tool 104 in a direction opposite to the target state ST, thereby allowing the user to know in which direction to move the tool 104 to reach the target state ST. For example, the user can feel these haptic interaction effects because it is easier for the tool 104 to move toward the target state ST compared to moving away from the target state ST (e.g., the user may feel that more effort is required to move the tool 104 away from the target state ST compared to moving it toward the target state ST). In other words, the user may feel as if a physical spring is interconnecting the guidance coordinate system GF of the tool 104 to the target coordinate system TF (see the figure of the spring and damper in FIG. 6).

[0118] One or more guide constraints GC include up to three guide constraints GC associated with a target position PT and up to three guide constraints GC associated with a target orientation OT and can be used by a control system 124 to guide a user. As will be described in more detail below, the control system 124 is operative to calculate a constraint force Fc that satisfies the guide constraints GC (and other virtual constraints VC if used). The constraint force Fc incorporates a virtual attraction force VF (e.g., a force and / or a torque) therein to draw the tool 104 to a target state ST. Each guide constraint GC is considered a one-dimensional virtual constraint VC. In some embodiments, the guide constraint GC is a velocity impulse constraint. In some embodiments, the constraints are similar to those used in impulse modeling described in U.S. Patent No. 9,119,655 entitled "Surgical Manipulator Capable of Controlling a Surgical Instrument in Multiple Modes" previously referenced. In some embodiments, these virtual constraints VC are defined only in an induced tactile mode and not in a manual mode or a semi-autonomous mode. In some embodiments, the virtual constraints VC are used in all modes. Other configurations are contemplated.

[0119] In FIG. 6, three guide constraints GC associated with a target position PT are illustratively shown as defined in a target coordinate system TF. The constraint force Fc ultimately calculated as a result of these three guide constraints GC is shown as including an attraction force incorporating a spring parameter PS and a damping parameter PD that direct the tool center point TCP of the tool 104 to the target position PT (e.g., to the origin of the target coordinate system TF). This is but one example. The constraint force Fc can include components of force and torque to align the tool 104 in a target orientation.

[0120] The guide constraint GC (and other virtual constraints VC if used) is mainly defined by three runtime parameters: the constraint Jacobian Jp, the desired velocity Vdes (or Vp2), and the constraint distance Δd. The Jacobian Jp maps each one-dimensional guide constraint GC into the coordinate system used in the virtual simulation VS (e.g., the virtual mass coordinate system VM). The desired velocity Vdes (or Vp2) is the scalar velocity of the guide constraint GC in the target coordinate system TF. Here, the desired velocity Vdes can be zero when the patient P is not moving and the associated target state ST defined for the patient P is not moving. However, when the patient P is moving, the target state ST may be associated with the patient P and thus may not be zero. The constraint distance Δd indicates how close the guide coordinate system GF is to the constraint and whether a constraint violation has occurred. In some cases, Δd refers to the distance / angle of the current state SC from the target state ST, and whenever the current state SC does not match the target state ST in the relevant degrees of freedom, a guide constraint GC violation occurs.

[0121] The guide constraint GC is not completely rigid. Instead, each guide constraint GC has an adjustment parameter TPA for adjusting the rigidity of the virtual constraint VC (e.g., by incorporating a spring parameter PS and / or a damping parameter PD). Such an adjustment parameter TPA may include a constraint force mixing parameter C and an error reduction parameter ε. The spring parameter PS and the damping parameter PD can be adjusted during operation in the induced tactile mode or between other modes as described in more detail below. In some embodiments, the value of the adjustment parameter TPA may vary based on the relationship between the current state SC and the target state ST. For example, the adjustment parameter TPA may be configured such that the rigidity increases as the tool 104 approaches the target state ST, or the adjustment parameter TPA may potentially decrease in rigidity as the tool 104 approaches the target state ST. The adjustment parameter TPA may be different for each guide constraint GC. For example, the guide constraint GC may include a first virtual constraint VC having a first value of the adjustment parameter TP1 and a second virtual constraint VC having a second value of the adjustment parameter TPA, where the first value is greater than the second value such that a virtual attraction force VF (e.g., a force and / or a torque) resulting as a consequence embodied in the constraint force Fc pulls the tool 104 more strongly as a result of the first virtual constraint VC compared to the second virtual constraint VC. The value of the adjustment parameter TPA may be greater (e.g., stiffer) for position constraints than for direction constraints, or vice versa. Other configurations are contemplated.

[0122] The adjustment parameter TPA can be set to remain constant regardless of the distance / angle from the current state SC to the target state ST, to increase / decrease exponentially according to the distance from the current state SC to the target state ST, to vary in proportion to the distance between the current state SC and the target state ST, to vary depending on the direction of the constraint, to take into account the influence of gravity, etc. The adjustment parameter TPA for one virtual constraint VC associated with one degree of freedom DOF can be set based on a relationship associated with another degree of freedom DOF (for example, the stiffness of the x-axis constraint may vary based on the distance along the y-axis between the current state SC and the target state ST). The adjustment parameter TPA can also vary according to the direction in which the tool 104 needs to move to reach the target state ST (for example, it is more rigid when moving in one direction along the x-axis compared to the opposite direction along the x-axis). The adjustment parameter TPA can also be scaled according to the constraint force Fc finally calculated based on the guide constraint GC, such as by increasing or decreasing the stiffness according to the magnitude of the constraint force Fc or any of its components. In some cases, a fixed value of one or more virtual gravitational forces VF can also be added to the virtual simulation VS.

[0123] The adjustment parameter TPA of the guide constraint GC can be set so that the user can easily move the tool 104 away from the target position PT and / or the target direction OT. In other words, the adjustment parameter TPA can be set such that, in the virtual simulation VS, the influence of the force and torque applied by the user can exceed the influence of the virtual gravitational force VF (e.g., force and torque). Thus, the control system 124 can be configured such that the user can relocate and / or reorient the tool 104 away from the target position PT and / or the target direction OT even when the guide constraint GC is enabled. The adjustment parameter TPA of the guide constraint GC can be set preoperatively or intraoperatively, can be updated intraoperatively, or can be a combination thereof. The adjustment parameters TPA and their values, their correlations with specific relationships, and the ways in which they can be scaled can be stored in one or more look-up tables within any suitable memory 140 of the control system 124 for later retrieval.

[0124] Each guide constraint GC also has a configuration parameter CPA. The configuration parameter CPA can include information regarding adjustment parameters TPA such as a constraint force mixing parameter C and an error reduction parameter ε, an upper force limit FLU and / or a lower force limit FLL, and / or an upper constraint distance offset DOU and / or a lower constraint distance offset DOL. The upper and lower force limits FLU, FLO refer to the limits of the forces calculated for each guide constraint GC that are ultimately solved by the constraint solver 192 to generate the constraint force Fc, as further explained below. The guide constraint GC is a bilateral constraint (e.g., the forces calculated to satisfy the constraint can be positive or negative), and the force limits FLU, FLO can be set high in the positive and negative directions (e.g., -100,000 / +100,000 Newtons) or with any limits. The upper and lower constraint distance offsets DOU, DOL determine the timing at which the constraint becomes active. For the guide constraint GC, the upper and lower constraint distance offsets DOU, DOL can be set such that the constraint becomes active whenever the current state SC is different from the target state ST.

[0125] Figure 7 shows a process executed to implement a haptic guidance mode in some embodiments. Here, the motion control 178 includes a path handler 188, a guidance handler 190, a constraint solver 192, and a virtual simulator 194. The motion control 178 further includes a boundary handler 196 for generating a virtual boundary constraint BC based on one or more virtual boundaries 174 generated by the boundary generator 172. The path handler 188, the guidance handler 190, the constraint solver 192, the virtual simulator 194, and the boundary handler 196 are each stored in the non-transitory memory 140 of any one or more of the aforementioned controllers 132, 134, 136 and include executable software implemented by the control system 124. Each part of the motion control 178 introduced above will be described in more detail below.

[0126] The guidance handler 190 obtains the target state ST of the tool 104 and generates one or more guidance constraints GC based on the target state ST and the current state SC of the tool 104. As shown in Figure 7, the two inputs to the guidance handler 190 include the current state SC and the target state ST. Since the last commanded pose CP correlates with the current pose of the tool 104, the current state SC can be defined with respect to the last commanded pose CP. The target state ST is defined in an anatomical coordinate system, an anatomical tracker coordinate system, etc. and can be transformed into a common coordinate system with the current state SC. Other inputs to the guidance handler 190 include configuration parameters CPA and adjustment parameters TPA for the guidance constraint GC. The guidance handler 190 defines one or more guidance constraints GC based on the relationship between the current state SC and the target state ST, and the relationship between the configuration parameters CPA and the adjustment parameters TPA. The guidance constraint GC is output from the guidance handler 190 to the constraint solver 192.

[0127] A variety of virtual constraints VC, including guide constraints GC, path constraints PC, boundary constraints BC, and other constraints, can be supplied to the constraint solver 192. These virtual constraints VC can be turned on / off by the control system 124. For example, in some cases, path constraints PC, boundary constraints BC, and other constraints may not be generated. Similarly, in certain operating modes, guide constraints GC may not be generated. All of the virtual constraints VC used in the motion control 178 can affect the movement of the tool 104. For purposes of illustration, only the guide constraints GC will be described in detail.

[0128] The constraint solver 192 calculates a constraint force Fc that is virtually applied to the tool 104 in the virtual simulator 194 based on the virtual constraints VC supplied to the constraint solver 192. In the haptic guidance mode, the constraint force Fc includes components of force and / or torque that are adapted to attract the tool 104 from the current state SC towards the target state ST based on one or more guide constraints GC. If only the guide constraints GC are input to the constraint solver 192, the constraint force Fc can be regarded as the virtual attraction force VF described above. However, when other virtual constraints VC are used, the constraint solver 192 has the ultimate task of providing a solution for the constraint force Fc that satisfies all of the virtual constraints VC, and thus other virtual constraints VC can also affect the magnitude / direction of the constraint force Fc. In these cases, the virtual attraction force VF (e.g., force and / or torque) is regarded as the force and torque components of the constraint force Fc directed towards the target state ST as a result of the guide constraints GC.

[0129] Referring to the constraint equation CEQ shown in FIG. 8, the constraint solver 192 arranges the constraint data of each virtual constraint VC in matrix form in the corresponding rows of the constraint equation CEQ to solve for Fp. Here, Fp is the force vector in the target coordinate system TF, and each component of Fp is a scalar constraint force acting in the corresponding constraint direction. To solve for Fp, the equations shown in FIG. 8 are transformed into matrix equations where each row represents a single one-dimensional virtual constraint VC, as will be described in more detail below. The constraint data is arranged in the constraint equation CEQ along with other information known to the constraint solver 192, such as the external force Fcgext, the damping force Fdamping, the inertial force Finertial, the virtual mass matrix M, the virtual mass velocity Vcg1, and the time step Δt (e.g., 125 microseconds).

[0130] The virtual mass matrix M is a combination of a 3×3 mass matrix and an inertia matrix. The damping force and the inertial forces Fdamping and Finertial are either calculated by the virtual simulator 194 or are otherwise known and are based on the virtual mass velocity Vcg1 (e.g., the velocity of the virtual mass coordinate system VM) output by the virtual simulator 194 at the previous time step. The virtual mass velocity Vcg1 is a six-degree-of-freedom (DOF) velocity vector including linear and angular velocity components. The damping force Fdamping is a six-DOF force / torque vector calculated as a function of the virtual mass velocity Vcg1 and the damping coefficient matrix (the linear and rotational coefficients may not be equal). Damping is applied to the virtual mass to improve its stability. The inertial force Finertial is also a six-DOF force / torque vector calculated as a function of the virtual mass velocity Vcg1 and the virtual mass matrix M. The damping force and the inertial forces, Fdamping and Finertial, can be determined by the method described in U.S. Patent No. 9,566,122 entitled "Robotic System and Method for Transitioning Between Operating Modes", the disclosure of which is hereby incorporated by reference in its entirety.

[0131] Constraint solver 192 can be composed of any suitable algorithm instructions (e.g., iterative constraint solver, projected Gauss - Seidel solver, etc.) to solve the system of equations CEQ in order to find the solution that best satisfies the system of equations (e.g., best satisfies various virtual constraints VC). In some cases, not all virtual constraints VC may be satisfied simultaneously. For example, if the motion is overly constrained by various virtual constraints VC, the constraint solver 192 finds an essentially "optimal" solution considering the relative stiffness / damping of the various virtual constraints VC. The constraint solver 192 solves the system of equations and finally outputs the constraint force Fc.

[0132] When using a projected Gauss - Seidel solver, the constraint solver 192 creates matrices A and b based on the virtual constraints VC, uses the projected Gauss - Seidel solver to solve the system of equations, and determines the resulting force vector Fp. Next, the constraint solver 192 receives the output of the projected Gauss - Seidel solver and transforms it from the target coordinate system TF (e.g., the constraint coordinate system) to the virtual mass coordinate system VM. For example, using the equation Fc = JpTFp, Fc is the constraint force, and each resulting force vector Fp is transformed into a force / torque vector applied to the virtual mass coordinate system VM.

[0133] A method for solving a system of equations with multiple constraints using a projected Gauss-Seidel solver is shown, for example, in “Constraint based physics solver” by Marijn Tamis and Giuseppe Maggiore, June 15, 2015 (v1.02), which can be found at http: / / www.mft-spirit.nl / files / MTamis_ConstraintBasedPhysicsSolver.pdf, or in “Comparison between Projected Gauss-Seidel and Sequential Impulse Solvers for Real-Time Physics Simulations”, by Marijn Tamis, July 1, 2015 (v1.01), which can be found at http: / / www.mft-spirit.nl / files / MTamis_PGS_SI_Comparison.pdf; both of these are hereby incorporated by reference in their entirety into this specification.

[0134] The projected Gauss-Seidel solver method addresses the linear complementarity problem LCP. Some constraint types (e.g., one-sided virtual constraints VC such as boundary constraints BC) can only push or "apply force" in one direction (e.g., positive constraint force), resulting in inequalities related to the LCP. If the force calculated for such a virtual constraint VC is negative (or, more generally, outside its tolerance) for a given iteration of the invalid constraint solver 192, the given virtual constraint VC must be pruned (or limited / upper bounded by the allowable values FLU, FLO of the upper or lower limit), and the remaining virtual constraints VC are solved until an appropriate result (such as convergence) is found. In this way, the constraint solver 192 determines the active set of virtual constraints VC for a given time step and then solves their values. Other virtual constraint VC types can apply forces in both positive and negative directions (e.g., two-sided virtual constraints VC). Such virtual constraints VC include guide constraints GC used to guide the user to move the tool 104 towards the target state ST. Such two-sided virtual constraints VC are usually active when enabled and are not pruned / limited during the iterations of the constraint solver 192.

[0135] The constraint force Fc calculated by the constraint solver 192 includes three components of force along the x, y, and z axes and three components of torque around the x, y, and z axes. The virtual simulator 194 utilizes the constraint force Fc in its virtual simulation VS together with the external force Fcgext, the damping force Fdamping, and the inertial force Finertial (all of which may include the six components of force / torque). In some cases, these components of force / torque are first converted to a common coordinate system (e.g., the virtual mass coordinate system VM) and then summed to define the total force FT. The resulting six-degree-of-freedom DOF force (e.g., force and torque) is applied to the virtual rigid body VRB, and the resulting motion is calculated by the virtual simulator 194. Thus, the virtual simulator 194 functions, among other things, to effectively simulate how various virtual constraints VC affect the motion of the virtual rigid body VRB. The virtual simulator 194 performs forward dynamics to calculate the resulting six-degree-of-freedom DOF pose and velocity of the virtual rigid body VRB based on a given total force FT applied to the virtual rigid body VRB. In some embodiments, the virtual simulator 194 comprises a physical engine implemented as executable software stored in the non-transitory memory 140 of any one or more of the aforementioned controllers 132, 134, 136 and implemented by the control system 124.

[0136] In the case of virtual simulation VS, the virtual simulator 194 models the tool 104 as a virtual rigid body VRB within the virtual mass coordinate system VM in a state where the origin of the virtual mass coordinate system VM is located at the center of mass of the virtual rigid body VRB and the coordinate axes are aligned with the principal axes of the virtual rigid body VRB. The virtual rigid body VRB is the dynamic object for the purpose of the virtual simulation VS and the rigid body representation of the tool 104. The virtual rigid body VRB can move freely according to the six degrees of freedom DOF of the Cartesian space in accordance with the virtual simulation VS. The virtual simulation VS may be computationally processed without a visual or graphical representation. Therefore, the virtual simulation VS does not need to display the dynamics of the virtual rigid body VRB. In other words, the virtual rigid body VRB does not need to be modeled within the graphics application executed by the processing unit. The virtual rigid body VRB may exist only with respect to the virtual simulation VS. However, other configurations are contemplated.

[0137] The virtual rigid body VRB and its characteristics (such as mass, inertia matrix, center of gravity, principal axes, etc.) define how the tool 104 moves in response to the applied forces and torques (such as the forces and torques applied by the user, and the total force FT incorporating the virtual gravitational force VF and / or torque). The virtual rigid body VRB governs whether the tool 104 feels heavy or light and how the tool 104 moves in response to the applied forces and torques (e.g., accelerates in translation and / or rotation). By adjusting the characteristics of the virtual rigid body VRB, the control system 124 can adjust how the tool 104 feels to the user. It may be desirable to have characteristics of the virtual rigid body VRB that are modeled to be reasonably close to the actual characteristics of the tool 104, such as providing as realistic as possible but not essential movement / tactile sensations. For reasons of control stability (e.g., when given the finite acceleration of the manipulator, control latency, etc.), the virtual mass and inertia can be modeled to be somewhat higher than that of the physical tool 104.

[0138] The virtual rigid body VRB can correspond to components that can be on or within tool 104. Further, or alternatively, the virtual rigid body VRB can extend partially beyond the physical tool 104. The virtual rigid body VRB can consider a tool 104 with an energy applicator 114 or a tool 104 without an energy applicator 114. Further, the virtual rigid body VRB may be based on the tool center point TCP. In one example, the center of gravity of the virtual rigid body VRB is understood to be the center point about which the virtual rigid body VRB rotates when a virtual force is applied to another point of the virtual rigid body VRB and the virtual rigid body VRB is not otherwise constrained (e.g., not constrained by the manipulator 102). The center of gravity of the virtual rigid body VRB can be close to the actual center of gravity of the tool 104, but does not have to be the same. The center of gravity of the virtual rigid body VRB can be determined empirically. When the tool 104 is attached to the manipulator 102, the position of the center of gravity can be reset to accommodate the preferences of individual users.

[0139] The virtual simulator 194 effectively simulates the rigid body dynamics of the tool 104 by virtually applying forces and / or torques to the virtual rigid body VRB in the virtual simulation VS, for example, by applying the components of the forces and torques from the total force FT to the center of gravity of the virtual rigid body VRB in the virtual mass coordinate system VM. Thus, the force / torque virtually applied to the virtual rigid body VRB can include the external force Fcgext (e.g., based on the input from one or more sensors 180), the damping force Fdamping, the inertial force Finertial, and the force / torque from the constraint force Fc associated with various virtual constraints VC (by being embodied as the constraint force Fc).

[0140] The rigid body Jacobian can be used to transform velocities and forces from one coordinate system (or "reference frame") to another on the same virtual rigid body VRB, and here it is used to transform the forces and torques of the external force Fext to the virtual mass coordinate system VM (for example, to generate the external force Fcgext used in the constraint equation CEQ). Next, the virtual simulator 194 internally calculates the damping force Fdamping and the inertial force Finertial to determine the total force FT, and also outputs the damping force Fdamping and the inertial force Finertial in the system of equations for the next time step for use by the constraint solver 192.

[0141] As shown in FIGS. 9 and 10, the virtual forward dynamics algorithm VFA can be used in the virtual simulation VS to simulate the movement of the virtual rigid body VRB when the total force FT is applied. In fact, the virtual forward dynamics algorithm VFA solves the equation F = ma (or a = F / M) in six degrees of freedom DOF and integrates the acceleration to generate the velocity. This is used to determine the new pose, as shown in FIG. 10. The control system 124 inputs virtual forces and / or torques (e.g., the total force FT) to the virtual simulator 194, and these virtual forces and / or torques are applied to the virtual rigid body VRB at the center of gravity (e.g., CG) in the virtual simulation VS when the virtual rigid body VRB is at the initial velocity and the initial pose. The virtual rigid body VRB moves to the final pose with different states (e.g., position and / or orientation) at the final velocity in the Cartesian space in response to the control system 124 that satisfies the input virtual forces and / or torques. The next commanded pose CP sent to the motion control 182 is based on the final pose calculated by the virtual simulator 194. Therefore, as shown in FIG. 10, the virtual simulator 194 operates to determine the next command pose CP by simulating the effect of applying the total force FT to the virtual rigid body VRB using virtual forward dynamics.

[0142] The speed limit VL may be imposed on the virtual rigid body VRB of the virtual simulation VS. In some cases, the speed limit VL can be set high so as not to generally affect the virtual simulation VS, or can be set to any desired value. The virtual rigid body VRB is in an initial pose (e.g., initial state) and has an initial velocity at the start of each iteration of the virtual simulation VS (e.g., each time step / interval dt). The initial pose and initial velocity can be defined as the final pose and final velocity output by the virtual simulator 194 at the previous time step.

[0143] Finally, the virtual simulator 194 calculates and outputs the next commanded pose CP based on its virtual simulation VS. The control system 124 is configured to command the manipulator 102 to move the tool 104 based on the commanded pose CP, which guides the user to place the tool 104 in the target state ST by providing the user with haptic feedback that guides the user to place the tool 104 in the target state ST, ideally causing the movement of the tool 104. Thus, the user can manually operate the tool 104, while the control system 124 assists in guiding the movement of the tool by utilizing the guidance constraint GC. The forces and torques applied to the tool 104 by the user (e.g., those detected by the sensor 180) can affect the overall movement of the tool 104 because the external force Fext is combined with the constraint force Fc before the virtual simulation VS for determining the commanded pose CP is executed. In some cases (e.g., time steps), the total force FT includes components of force and torque that form an external force Fext that is large enough and in a direction to overcome the forces and torques of the constraint force Fc and allow the tool 104 to move away from the target state ST. However, as described above, the guidance constraint GC has configurable stiffness and damping (e.g., based on the spring parameter PS and the damping parameter PD) that can be adjusted to reduce the influence of the external force Fext in certain situations.

[0144] Figure 11 summarizes the various steps executed by the motion control 178. These include the steps executed by the constraint solver 192 and the virtual simulator 194 as described above. In step 1100, the external force Fext is calculated based on the readings obtained from the sensor 180. In step 1102, the constraint data related to the various virtual constraints VC is supplied to the constraint solver 192 from the path handler 188, the guide handler 190, the boundary handler 196, and / or other constraint sources.

[0145] In steps 1104 - 1108, the rigid body calculations are executed by the virtual simulator 194 to determine the inverse mass matrix M-1, the inertial force Finertial, and the damping force Fdamping of the virtual rigid body VRB. In steps 1110 - 1114, the constraint solver 192 utilizes the output from the rigid body calculations executed in steps 1104 - 1108 and the constraint data provided in step 1102 to perform the aforementioned constraint force calculations and ultimately generate the constraint force Fc. In step 1116, the constraint force Fc is summed with the external force Fext, the damping force Fdamping, and the inertial force Finertial that have been transformed into the virtual mass coordinate system VM (Fcgext) to generate the total force FT. In step 1118, the total force FT is applied to the virtual rigid body VRB in the virtual simulation VS performed by the virtual simulator 194. In step 1120, the new pose and velocity of the virtual rigid body VRB are determined, and finally, in step 1122, the new pose and velocity are transformed to the tool center point TCP. The new command pose CP (TTCP) and velocity (VTCP) are output by the virtual simulator 194 in step 1124.

[0146] Referring now to FIG. 12, a portion of the surgical system 100 including one of the tools 104 of FIG. 1 and the generally depicted target site TS are schematically shown, where the target site TS is supported at a work surface WS, such as an operating table (not shown in detail). Here, the target site TS represents a part of the anatomical structure of the patient P, such as bone or another type of tissue, that is treated during a surgical procedure. For this purpose, the tool 104 is shown spaced from the target site TS along a trajectory T, which, as described above, is monitored by the navigation system 128 from the tracking state of the first patient tracker 160A fixed to the target site TS, or is otherwise known to this system. For illustrative purposes, the first tool tracker 160G is shown firmly fixed to the tool 104. However, although the navigation system 128 can track the states of the plurality of trackers 160 within a common coordinate system as described above, the pose of the object being tracked (e.g., the tool 104) can be determined by other means (e.g., based on known geometric relationships) and transformed between coordinate systems (e.g., between the manipulator coordinate system MNPL and the localizer coordinate system LCLZ). In other words, since the shapes of the tool 104 and the energy applicator 114 are known, among other things, the surgical system 100 can determine the change in the pose of the tool 104 relative to the first patient tracker 160A without necessarily using the illustrated first tool tracker 160G.

[0147] In this representative example, tool 104 similarly includes a mount 148 (shown in phantom) to facilitate releasable attachment of the manipulator 102 to coupling 110, and instrument 112 is realized as a powered surgical device 150 with a power generation assembly 152 (shown in phantom) driven by tool controller 136 or another part of control system 124. Here, power generation assembly 152 is realized as an electric motor configured to selectively generate rotational torque about drive shaft AD to drive one or more types of energy applicators 114. For this purpose, powered surgical device 150 includes a chuck assembly 198 (see FIG. 12, shown in phantom) arranged in rotational communication with power generation assembly 152 to facilitate releasable attachment of energy applicator 114, which in this illustrative embodiment is realized by bar 154 (accessories are not shown in detail). However, tool 104, instrument 112, and / or energy applicator 114 can be in several different configurations without departing from the scope of the present disclosure. Here, tool 104 includes a processing area 200 arranged to be gripped by a user and having a trigger that can function as an input device 146 (e.g., start and stop rotation of energy applicator 114). In some embodiments, tool 104 and / or powered surgical device 150 can be similar to those shown in U.S. Patent No. 9,566,121, entitled "End Effector of a Surgical Robotic Manipulator". In some embodiments, tool 104 and / or powered surgical device 150 can be similar to those shown in U.S. Patent Application Publication No. 2018 / 0110572 A1, entitled "Systems and Tools for Use With Surgical Robotic Manipulators", the entire disclosure of which is incorporated herein by reference. Other configurations are contemplated.

[0148] Continuing to refer to FIG. 12, the power generation assembly 152 of the powered surgical device 150 is operably attached to the mount 148 by a frame 202 (generally shown in phantom), for example by one or more fasteners (not shown). The frame 202 is formed separately from the mount 148 in the illustrated embodiment, although other configurations are contemplated, and the mount 148 is formed from any suitable number of components sufficient to facilitate attachment to the manipulator 102, or otherwise achievable thereby. Similarly, the frame 202 can likewise be defined by several different components that cooperate to support the power generation assembly 152 and other portions of the tool 104. In some embodiments, one or more covers 204 can be used by the tool 104 to conceal, protect, or otherwise shield certain components (e.g., the mount 148) from the external environment. The cover 204 can also conceal electrical components (e.g., wires, electrical connectors, printed circuit boards, etc.) and is shaped and positioned to allow access to a sterilization interface system (not shown but generally known in the relevant art) disposed between the mount 148 and the coupling 110 of the manipulator 102 to facilitate removably attaching the tool 104 to the manipulator 102. Here, the releasable attachment of the coupling 110 to the mount 148 can be accomplished in several different ways sufficient to secure the tool 104 to the manipulator 102.

[0149] In FIG. 12, a portion of the target site TS is shown in phantom, and for illustrative purposes, shows the intended volume of tissue (e.g., bone) to be removed by the bar 154 along a trajectory T that functions as a milling path MP in this representative example. Again, the intended "depth" of tissue removal at the target site TS is represented by a target reference point TRP that can be defined as a coordinate system, similar to the tool center point TCP. Here, both the tool center point TCP and the target reference point TRP are shown disposed along the trajectory T.

[0150] Continuing from FIG. 12 to FIG. 13A, the tool 104 advances along the trajectory T maintained by the manipulator 102, such as by operating the manipulator 102 in one or more of the various modes described herein, together with the bar 154 of the energy applicator 114 disposed along the trajectory T, so as to engage the target site TS. More specifically, the tool center point TCP of the energy applicator 114 defined by the bar 154 is disposed along the trajectory T, and the energy applicator 114 rotates about a drive axis AD that is similarly aligned with the trajectory T. Here, the tool center point TCP is spaced apart from the target reference point TRP to indicate the remaining volume of tissue (e.g., bone) removed by the bar 154 as the tool 104 advances along the trajectory T. This is shown in FIG. 13B with the tool center point TCP disposed closer to the target reference point TRP (compared to FIGS. 13B and 13A).

[0151] FIGS. 14A - 14D sequentially show a virtual "runaway" state of the surgical system 100 that can occur in a particular use case where another portion of the energy applicator 114 or the tool 104 is effectively "attached" to the manipulator 102 and the target site TS and the tool 104 move together in one or more degrees of freedom DOF, either instantaneously or over a long period of time. Here, by way of illustrative example, the energy applicator 114 may encounter other types of increased resistance caused by, for example, changes in tissue type or properties, irregularities, or friction and / or heat, degradation of cutting performance, accumulation of tissue fragments (e.g., "cut ends"), etc., which may interrupt tissue removal and be large enough to cause the energy applicator 114 to become "locked" to the tissue at the target site TS, either instantaneously or over a long period of time. In some cases, due to the above resistance, the energy applicator 114 may become "locked" to the tissue at the target site TS away from the trajectory T.

[0152] The above-described fictional scenario can be explained by comparing FIGS. 14A-14B. Here, in FIG. 14A, the energy applicator 114 is engaged with the target site TS and encounters a large resistance to rotation around the drive shaft AD, causing the tool center point TCP to deviate from the trajectory T maintained by the manipulator 102 and resulting in the energy applicator 114 becoming "locked" to the target site TS, as shown by the exaggerated misalignment between the trajectory T shown in FIG. 14B and the drive shaft AD. The target state ST of the tool 104 can be defined in several different ways, but for the purposes of this representative example, the target state ST includes a simultaneous alignment between the drive shaft AD and the trajectory T. However, the current state SC of the tool 104 shown in FIG. 14B includes a misalignment between the drive shaft AD and the trajectory T where the energy applicator 114 is "locked" to the target site TS, so a "runaway" state can occur when the manipulator 102 attempts to move from the current state SC to the target state ST. The "runaway" state can also occur as a result of the patient tracker 160 loosening from the target site TS, thereby causing a loss of tracking accuracy.

[0153] In this illustrative example, as shown by successively comparing FIGS. 14B-14D, the movement of the tool 104 towards the target site ST also results in a corresponding movement of the target site TS that defines the trajectory T (and thus the target state ST) based on the tracked state of the first patient tracker 160A monitored by the navigation system 128 as described above. In other words, when the manipulator 102 attempts to move the tool 104 from the current state SC to the target state ST (e.g., such that the drive shaft AD returns to simultaneous alignment with the trajectory T), the target site TS moves with the tool 104 and the target state ST is not reached (e.g., simultaneous alignment does not occur). As shown in FIGS. 14C-14D, this can ultimately cause the target site TS to be "lifted" from the work surface WS.

[0154] Various techniques for detecting and / or responding when a "runaway" condition occurs are disclosed herein. For this purpose, and as will be described in more detail below, in some embodiments, the surgical system 100 uses the tool 104 to engage the target site TS, and the manipulator 102 is configured to support the tool 104 with respect to the target site TS (e.g., the target state ST in which the tool center point TCP is disposed along the trajectory T). As will be described in more detail below, the sensing system 206 (see FIGS. 1-2) is configured to detect one or more system conditions SYC associated with one or more of the tool 104, the manipulator 102, the target site TS, or combinations thereof. A controller 124 coupled to the manipulator 102 and the sensing system 206 (e.g., the manipulator controller 132, the tool controller 136, or another suitable controller of the surgical system 100, see FIG. 25) is configured to operate the manipulator 102 between a first mode M1 that maintains the alignment of the tool 104 with respect to the target site TS according to a first constraint criterion C1 and a second mode M2 that maintains the alignment of the tool 104 with respect to the target site TS according to a second constraint criterion C2 that is different from the first constraint criterion C1. The controller 124 is further configured to change the operation of the manipulator 102 from the first mode M1 to the second mode M2 in response to determining that at least one of the one or more system conditions SYC satisfies a predetermined condition PR. The sensing system 206, the system conditions SYC, the first and second modes M1, M2, the first and second constraint criteria C1, C2, and the predetermined condition PR will each be described in more detail below, but the techniques described herein can be utilized both in connection with the tool 104 that engages the target site TS via the energy applicator 114 and in connection with the tool 104 that engages the target site TS via the implantable component 116 as shown in FIG. 15. However, other configurations are contemplated and additional techniques will be described in detail below.

[0155] In some implementations, the first mode M1 and the second mode M2 can be activated and deactivated, and for example, can be separate distinct operating modes of the manipulator 102 such that a user can be directly notified of the mode change or there is a pause between mode changes. Alternatively, however, in another embodiment, the first and second modes M1 and M2 can be understood as different ways of controlling the manipulator 102 according to a feedback control scheme. For example, the constraint criteria C1, C2 can be changed in real-time or near real-time without activating or deactivating a particular mode, without directly notifying a user, or without pausing between mode changes. In other words, the constraint criteria C1, C2 can be changed in a seamless transition regardless of whether a user recognizes or initiates either of the modes M1, M2. Any combination of these implementations is contemplated, and the terms "first mode" and "second mode" should be understood to inclusively cover any of these implementations without limitation.

[0156] In one implementation, the values of the first and second constraint criteria C1, C2, and associated parameters are determined or pre-determined preoperatively based on information such as clinical data, experimental data, surgeon preferences, or system default settings. In another implementation, the values of the first and second constraint criteria C1, C2, and any associated parameters can be determined and / or adjusted dynamically and intraoperatively by a controller that detects forces occurring between the system conditions SYC, or the target site and the manipulator, based on measurements from a sensing system, sensors, navigation system, etc. In other implementations, one of the first and second constraint criteria C1, C2 is determined or pre-determined preoperatively and the other of the first and second constraint criteria C1, C2 is determined intraoperatively.

[0157] Referring now to FIG. 15, a portion of the surgical system 100 including one of the tools 104 of FIG. 1 is shown adjacent to a generally depicted target site TS. In this embodiment, the tool 104 is configured to facilitate impacting an implantable component 116 (e.g., an artificial acetabular cup) at the target site TS (e.g., a reamed acetabulum) along a trajectory T maintained by the manipulator 102. For this purpose, the instrument 112 of the tool 104 is realized as a guide 208 that is attached, among other things, to a coupling 110 of the robotic arm 108 and is configured to support an impactor assembly 210 for relative movement in one or more degrees of freedom. The impactor assembly 210 includes, among other things, an interface 212 for releasably securing the implantable component 116 and a head 214 (e.g., applied by striking the head 214 with a mallet) arranged to receive an impact force FI.

[0158] In a representative embodiment shown in this specification, the implantable component 116 is a substantially hemispherical cup that forms part of an artificial hip joint adapted to the impaction of the acetabulum of patient P. Prior to impaction, the acetabulum of patient P is processed by reaming or other methods to define the target site TS. The processes of reaming, processing, and impaction are described in detail in U.S. Patent No. 8,979,859 titled "Depth of Impaction" and U.S. Patent No. 8,753,346 titled "Tool, Kit-of-Parts for Multi-Functional Tool, and Robotic System for Same", the disclosures of which are hereby incorporated by reference in their entireties. Although this disclosure describes various orthopedic procedures including hip joints, the subject matter described herein may be applicable to other joints of patient P's body B, such as, for example, the shoulder, elbow, wrist, spine, knee, ankle, etc. Further, the surgical system 100 of this disclosure can be utilized in connection with several different types of orthopedic surgeries, and the implantable component 116 can be of several different types, styles, configurations, etc. (e.g., cup, stem, screw, pin, rod, wire, anchor, prosthesis, etc.). Accordingly, various tools 104 are contemplated and various styles, types, and / or configurations of the guide 208, the impactor assembly 210, and / or the implantable component 116 can be utilized without departing from the scope of this disclosure.

[0159] Referring now to FIGS. 15 - 17B, an exemplary embodiment of the guide 208 is configured to facilitate the advantageous positioning of the implantable component 116 with the impactor assembly 210 prior to movement of the impactor assembly 210, and the implantable component 116 is limited by support by the guide 208 (and thus the manipulator 102). In other words, a user (e.g., a surgeon) can manually approach the target site TS with the implantable component 116 without first having to support the impactor assembly 210 with the guide 208. After the approach is manually completed and the implantable component 116 is positioned at the target site TS, the surgeon can then articulate the implantable component 116 and the impactor assembly 210 to engage with the guide 208 in a quick, efficient, and reliable manner, facilitating alignment of the implantable component 116 with the trajectory T maintained by the manipulator 102. With proper alignment maintained, the surgeon can apply an impact force FI to the head 214 of the impactor assembly 210 to attach the implantable component 116 to the target site TS. For this purpose, and as described in more detail below, the guide 208 is configured to allow movement of the impactor assembly 210 relative to the guide 208 in one or more degrees of freedom under certain operating conditions of the surgical system 100.

[0160] Referring now to FIGS. 16A-16B, the impactor assembly 210 generally includes an interface 212 for releasably securing the implantable component 116, and a head 214 arranged to receive the impact force FI as described above. The impactor assembly 210 also includes a flange 216 that defines a first engagement surface 218 adjacent to the guide 208 to limit the movement of the impactor assembly 210 during use, as will be described in more detail below. The impactor assembly 210 generally extends along a first axis A1 between a distal end 220 adjacent to the interface 212 and a proximal end 222 adjacent to the head 214. The flange 216 is disposed between the interface 212 and the head 214, has a spherical profile that defines the first engagement surface 218, and defines a flange reference point FRP along the first axis A1 disposed at the center of the flange 216 (e.g., at the geometric center of the spherical profile that defines the first engagement surface 218). Similarly, the implantable component 116 defines an implant reference point IRP along the first axis A1 of the impactor assembly 210 to which the prosthesis is releasably attached (see FIG. 15), and the target site TS defines a target reference point TRP along the trajectory T (see FIG. 15). The shaft 224 extends along the first axis A1 from the distal end 220 to the flange 216, and the handle 226 with the grip 228 extends between the flange 216 and the head 214. Each component of the impactor assembly 210 introduced above will be described in more detail below.

[0161] In a representative embodiment shown herein, the head 214, flange 216, and shaft 224 are defined by an impactor body generally designated 230, and the interface 212 is defined by a carrier shaft 232 housed within the impactor body 230. More specifically, the impactor body 230 defines a hollow region 234 that extends along a first axis A1 from the distal end 220 through the shaft 224 and handle 226 toward the head 214. The carrier shaft 232 generally extends along the first axis A1 between a distal shaft end 236 and a proximal shaft end 238, and one or more bearing regions 240 are provided therebetween to facilitate rotation and force distribution. The interface 212 is disposed at the distal shaft end 236 and releasably engages the implantable component 116 such that they move together when the implantable component 116 is attached to the impactor assembly 210. For this purpose, the interface 212 and the implantable component 116 each comprise a respective threaded engagement generally designated 242 (e.g., male and female threads, see FIG. 16A), thereby releasably attaching the implantable component 116 to the impactor assembly 210.

[0162] Adjacent to the threaded engagement 242 of the carrier shaft 232, the impactor body 230 includes a key portion 244 formed at the distal end 220 of the shaft 224. The key portion 244 has a generally rectangular profile shaped to engage a correspondingly shaped notch portion 246 formed in the implantable component 116 (see FIG. 15A, shown in phantom). This configuration allows the implantable component 116 to be indexed with respect to the shaft 224 (and thus the handle 226), which can be advantageous for applications where the implantable component 116 has certain features that need to be aligned with the target site TS. Further, this configuration also facilitates a releasable attachment between the implantable component 116 and the impactor assembly 210 in that the rotation and translation of the carrier shaft 232 with respect to the shaft 224 can be used to disengage the threaded engagement 242 without rotating the shaft 224 about the first axis A1. For this purpose, the handle 226 also includes a cage 248 disposed between the head 214 and the grip 228, corresponding to the knob 250 and shaped to facilitate access, and the knob 250 is then operably attached to the proximal shaft end 238 of the carrier shaft 232. In the illustrated embodiment, the knob 250 includes an axial knob aperture 252 formed along the first axis A1 and a lateral knob aperture 254 formed across the first axis A1 and disposed in communication with the axial knob aperture 252. The axial knob aperture 252 is shaped to receive the proximal shaft end portion 238 of the carrier shaft 232, and the lateral knob aperture 254 is shaped to receive a lateral pin 256 that is also received within a lateral shaft aperture 258 formed in the carrier shaft 232 (see FIG. 16B). In addition to ensuring retention of the carrier shaft 232, this configuration also allows the knob 250 and the carrier shaft 232 to rotate and translate simultaneously about the first axis A1.Here, the cage 248 of the handle 226 has a generally U-shaped profile and is configured to allow limited translation of the knob 250 along the first axis A1 while also providing the surgeon access to the knob 250.

[0163] Referring now to FIGS. 15 and 17A - 17B, as described above, the illustrated embodiment of the tool 104 includes a guide 208 for releasably securing an impactor assembly 210 so as to encourage, among other things, maintaining alignment of the first axis A1 with the trajectory T via the robot arm 108 of the manipulator 102. For this purpose, the guide 208 generally comprises a mount 148 (see FIG. 15, depicted generally in phantom) adapted to be attached to the manipulator 102, and a body 260 operably attached to the mount 148 and having a channel 262 extending along a second axis A2. In the representative embodiment shown herein, the body 260 of the guide 208 comprises one or more threaded holes 264 and recessed regions 266 (see FIGS. 17A - 17B) shaped and arranged to be fixed to the mount 148 (see FIG. 15, generally depicted) via a fastener (not shown) or the like. The mount 148 depicted in FIG. 15 is formed separately from the body 260 in the illustrated embodiment, although other configurations are contemplated, and the guide 208 is formed from any suitable number of components sufficient to facilitate attachment to the manipulator 102 or otherwise achievable thereby. Also here, in some embodiments, one or more covers 204 can be used with the guide 208 of the tool 104 to conceal, protect, or otherwise shield certain components (e.g., the mount 148) from the external environment. The cover 204 can also conceal electrical components (e.g., wires, electrical connectors, printed circuit boards, etc.) and can be shaped and arranged to allow access to a sterilization interface system (not shown but generally known in the relevant art) disposed between the mount 148 and the coupling 110 of the robot arm 108 to facilitate removably attaching the tool 104 to the manipulator 102. Also here, the releasable attachment of the coupling 110 to the mount 148 can be achieved in several different ways sufficient to secure the tool 104 to the manipulator 102.

[0164] As shown in FIGS. 17A - 17B, the channel 262 formed in the body 260 of the guide 208 defines an opening 268 that is arranged to receive a portion of the shaft 224 of the impactor assembly 210 therethrough. The guide 208 also includes a second engagement surface, generally denoted 270 (see also FIG. 15), and a limiter 272. The second engagement surface 270 is shaped to be adjacent to the first engagement surface 218, and the limiter 272 is configured to maintain the adjacency between the engagement surfaces 218, 270 and facilitate the coaxial alignment of the axes A1, A2 with the trajectory T maintained by the manipulator 102. The opening 268 of the guide 208 is configured such that the shaft 224 of the impactor assembly 210 can pass through when the guide 208 is disposed between the flange 216 and the interface 212 of the impactor assembly 210, so as to facilitate aligning the first axis A1 with the second axis A2. As indicated by the phantom line in FIG. 16A, the shaft 224 of the impactor assembly 210 has a first periphery 274, and the flange 216 of the impactor assembly 210 has a second periphery 276 that is larger than the first periphery 274. In other words, the flange 216 is larger than the shaft 224 and cannot pass through the opening 268 of the guide 208, but the shaft 224 is sized to be able to pass through the opening 268.

[0165] Continuing to refer to FIGS. 17A-17B, as described above, the limiter 272 of the guide 208 is configured to maintain the adjacency between the first engagement surface 218 and the second engagement surface 270 during impact and to facilitate the coaxial alignment of the axes A1, A2 with the trajectory T maintained by the manipulator 102. For this purpose, the limiter 272 of the illustrated embodiment includes a pair of fingers generally indicated at 278 disposed adjacent to the channel 262. The fingers 278 extend from the body 260 of the guide 208 to respective finger ends 280 spaced apart from each other so as to define an opening 268 therebetween (see FIG. 15). The fingers 278 also each define a respective arcuate surface generally indicated at 282. The arcuate surfaces 282 are arranged to contact the flange 216 of the impactor assembly 210 when the second engagement surface 270 is adjacent to the first engagement surface 218, maintain the adjacency between the first engagement surface 218 and the second engagement surface 270, and limit the movement of the impactor assembly 210 relative to the guide 208, as will be described below. The arcuate surface 282 of the limiter 272 is substantially continuous with the second engagement surface 270 of the guide 208, and both the second engagement surface 270 and the arcuate surface 282 are at least partially defined by the channel 262. More specifically, as best shown in FIG. 17A, the arcuate surface 282 of the limiter 272 and the second engagement surface 270 of the guide 208 have a substantially continuous and generally cylindrical C-shaped profile such that the channel 262 is spaced apart from the second axis A2 at a common radius 284 so as to define both the second engagement surface 270 and the arcuate surface 282.

[0166] When the impact force FI is applied to the head 214 of the impactor assembly 210, the implantable component 116 and the impactor assembly 210 necessarily translate along the trajectory T. Thus, the guide 208 and the impactor assembly 210 are configured to ensure that the adjacency between the first engagement surface 218 and the second engagement surface 270 is maintained as the flange 216 moves within the channel 262 (e.g., when a surgeon continuously strikes the head 214 of the impactor assembly 210 with a mallet). For this purpose, the channel 262 of the guide 208 (not shown in detail) extends between first and second axial channel ends 262A, 262B that are spaced apart from each other along the second axis A2 at a depth greater than the thickness of the flange 216. Here, the guide 208 defines a tool center point TCP that is disposed along the second axis A2 at the center of the channel 262 (e.g., equidistantly between the first and second axial channel ends 262A, 262B) in this embodiment. However, the tool center point TCP can be defined in other ways without departing from the scope of the present disclosure.

[0167] Since the flange 216 has a generally spherical profile as described above, only a portion of the flange 216 that defines the first engagement surface 218 actually engages the cylindrical channel 262 when the second engagement surface 270 is adjacent to the first engagement surface 218. Thus, the channel 262 is advantageously configured to be deep enough to ensure that the flange 216 can be easily placed within the channel 262 during impact and remain adjacent to the channel 262. However, maintaining the adjacency between the second engagement surface 270 and the first engagement surface 218 can be achieved in other ways. For example, it can be achieved by advancing the guide 208 along the trajectory T towards the target site TS using the manipulator 102 during impact (e.g., to position the tool center point TCP at the flange reference point FRP). Other configurations are contemplated.

[0168] As best shown in FIG. 17B, the body 260 of the guide 208 also includes a pocket 286 that houses a sensor subassembly 288, a follower subassembly 290, and an input module 292, each of which is described in more detail below. The pocket 286 extends to communicate with the channel 262 to facilitate attachment of the follower subassembly 290 located within the pocket 286 adjacent to the channel 262. Here, a portion of the follower subassembly 290 also defines a portion of the second engagement surface 270 (see FIG. 17A).

[0169] The sensor subassembly 288 generally includes a sensor housing 294 that is fixed to the body 260 of the guide 208 via a fixture (not shown in detail) and supports a first trigger sensor 296, a second trigger sensor 298, and an input sensor 300. Each sensor may be arranged to communicate (e.g., by wired or wireless electrical communication) with a controller 124 (e.g., a manipulator controller 132, a tool controller 136, or another suitable one) or other components of the surgical system 100. The input sensor 300 is arranged to engage or communicate with the input module 292, and the first and second trigger sensors 296, 298 are arranged to engage or communicate with the follower subassembly 290. As will be understood from the subsequent description below, each sensor of the sensor subassembly 288 can be of several different types, styles, configurations, etc., and other configurations other than those specifically shown herein are contemplated by the present disclosure.

[0170] The input module 292 is configured for selective actuation by a surgeon and generally includes an input frame 302 and an input button 304. The input frame 302 is fixed to the body 260 of the guide 208 via one or more fasteners (not shown in detail) and supports the input button 304 for movement relative thereto. The input button 304 includes a protrusion 306 arranged to engage an input sensor 300 in response to actuation by the surgeon (e.g., by pressing the input button 304). In some embodiments, the input button 304 can be elastically biased away from the input frame by a spring (not shown) or the like. However, other configurations are contemplated. The input module 292 can be configured to facilitate operating the manipulator 102 in different ways during a surgical procedure and can function as an input device 146.

[0171] The follower subassembly 290, like the sensor subassembly 288, is received within a pocket 286 formed in the body 260 of the guide 208 and is secured to the body 260 with a fastener (not shown in detail). The follower subassembly 290 generally includes a follower housing 308 that supports first and second triggers 310, 312 shaped and arranged to engage a flange 216 of the impactor assembly 210 in the illustrated embodiment. For this purpose, the first and second triggers 310, 312 extend within a channel 262 and are supported by the follower housing 308 to deflect toward the sensor subassembly 288 in response to engagement with the flange 216, and independently operate respective push rods (not shown) supported within the follower housing 308 that engage first and second trigger sensors 296, 298, respectively. Here, the follower subassembly 290 and the sensor subassembly 288 facilitate determining one or more of the presence of the flange 216 within the channel 262 and / or the relative position of the flange 216 between the first and second axial channel ends 262A, 262B, and are configured to promote "tracking" movement of the implantable component 116 along the trajectory T during an impact at the target site TS based on corresponding to a change in the axial position of the flange 216 along the channel 262.

[0172] As described above, the manipulator 102 is configured to maintain a generally linear trajectory T that is aligned with axes A1, A2 and is directed to place the tool 104 relative to the target site TS and, in the embodiment, to impart an impact to the implantable component 116. Here, an external impact force FI applied to the head 214 of the impactor assembly 210 travels through the impactor assembly 210 to the implantable component 116 and then advances the implantable component 116 along the trajectory T toward the target site TS. The process of imparting an impact to the implantable component 116 is described in more detail below, but maintaining the trajectory T can include the manipulator 102 that restricts all or certain types of movement of the guide 208 relative to the target site TS under certain conditions and / or, in some embodiments, can include restricting the movement of the guide 208 or directing it to translate along the trajectory T relative to the target site TS. The manipulator 102 can facilitate a surgeon to translate the guide 208 along the trajectory T and, in particular, to pass the shaft 224 of the impactor assembly 210 through the opening 268 of the guide 208 as described above. Certain steps of the surgical procedure can include controlling the manipulator 102 in different ways. Further, various configurations of the tool 104 are contemplated by the present disclosure, and in some embodiments, one or more portions of the surgical system 100, the tool 104, the instrument 112, and / or the implantable component 116 can be similar to those described in U.S. Patent Application Publication No. 2019 / 0231446A1, titled "End Effectors, Systems, And Methods For Impacting Prosthetics Guided By Surgical Robots", the disclosure of which is incorporated herein by reference in its entirety. Other configurations are contemplated.

[0173] Referring now to FIGS. 18 - 21D, a portion of the surgical system 100 and the generally depicted target site TS are schematically shown, with the target site TS being shown as supported on a work surface WS (e.g., an operating table, not shown in detail). Here, the target site TS represents the intended position of the implantable component 116 when impacted into the acetabular cup (the intended position shown in the phantom of FIG. 18). The acetabulum here is either reamed or otherwise processed to define a track T, and the first patient tracker 160A is firmly fixed thereto. As described above, the tracked state (e.g., position and / or orientation data, or data based thereon) of the first patient tracker 160A monitored by the navigation system 128 is used to facilitate maintaining a target state SA to ensure alignment of the manipulator 102 with the target site TS. This is done, for example, by controlling the robotic arm 108 of the manipulator 102 to maintain alignment of the second axis A2 defined by the guide 208 with the track T defined by the target site TS.

[0174] In FIG. 18, the mount 148 (represented by the cover 204 for purposes of illustration, see also FIG. 15) and the guide 208 of the tool 104 are disposed adjacent to a target site TS supported by the manipulator 102 (partially depicted and shown in phantom), with the second axis A2 aligned with the track T (and thus the tool center point TCP is disposed along the track T). The impactor assembly 210 is shown spaced from both the target site TS and the guide 208, with the implantable component 116 fixed to the interface 212 and disposed along the first axis A1. For purposes of illustration, the first tool tracker 160G is shown fixedly attached to the guide 208 and the second tool tracker 160I is shown fixedly attached to the impactor assembly 210. However, although the navigation system 128 can track the states of the plurality of trackers 160 within a common coordinate system as described above, the pose of the object being tracked (e.g., the tool 104) can be determined by other means (e.g., based on known geometric relationships) and transformed between coordinate systems (e.g., between the manipulator coordinate system MNPL and the localizer coordinate system LCLZ). In other words, the surgical system 100 can determine the change in pose of the tool 104 relative to the first patient tracker 160A without necessarily utilizing the illustrated first tool tracker 160G and / or the second tool tracker 160I. In particular, the shapes of the guide 208, the impactor assembly 210, and the implantable component 116 are known, and when the flange 216 is disposed within the channel 262 (e.g., via the sensor subassembly 288), the placement of the flange reference point FRP relative to the tool center point TCP can be determined.

[0175] Referring now to FIG. 19A, the impactor assembly 210 is moved to an initial position adjacent to the target site TS (here, the reamed acetabulum), together with the implantable component 116, and the first axis A1 is defined by the impactor assembly 210 in coaxial alignment with both the second axis A2 defined by the guide 208 and the trajectory T defined by the target site TS. Here, the flange 216 of the impactor assembly 210 is disposed within the channel 262 of the guide 208, and the flange reference point FRP is disposed in alignment with the tool center point TCP. The implant reference point IRP defined by the implantable component 116 is spaced from the target reference point TRP defined by the target site TS.

[0176] As described above, when operating in the haptic guidance mode or other modes, the surgical system 100 may be configured to interpret the forces detected by the input of sensor 180, which is used to drive the robotic arm 108 of the manipulator 102, and in particular, may enable the surgeon to contact or otherwise engage different parts of the robotic arm 108 and / or the tool 104 and move them in a particular direction during certain operating conditions. To illustrate this concept, FIG. 19A shows an applied force FA acting on the guide 208, such as when the surgeon manually pushes and / or pulls on the guide 208 or the impactor assembly 210 (details not shown). For the sake of explanation, if the manipulator 102 is not configured to maintain alignment with the trajectory T as shown here (e.g., if a target state ST is defined to result in a matching alignment between the second axis A2 and the trajectory T), the applied force FA shown in FIG. 19A may cause the tool 104 to move (via the robotic arm 108) to the position shown in FIG. 19B, causing the axes A1, A2 to deviate from the position where they match the trajectory T (as shown in FIG. 19A). In this hypothetical illustrative example, the surgeon may, as shown in FIG. 20A, successively align the axes A1, A2 with the trajectory T defined by the target site TS before and after the impact, and engage at the target site TS and adjust or finalize the initial positioning of the approach and implantable component 116 in the manual mode or another mode (e.g., activated via the input button 304) before maintaining the matching alignment with the manipulator 102 and operating the robotic arm 108.

[0177] In the illustrative example shown in FIG. 20A, the manipulator 102 operates to maintain alignment between the second axis A2 (defined by the guide 208) and the target site TS (e.g., via coincidence with the trajectory T), and it is also aligned with the first axis A1 (defined by the impactor assembly 210). Here, the target state ST can be defined by the tool center point TCP arranged along the trajectory T. When alignment is maintained by the manipulator 102 as shown here, the surgeon can apply an impact force FI to the head 214 of the impactor assembly 210, for example, by continuously hitting the head 214 with a mallet (not shown) to install the implantable component 116 at the target site TS. As shown in FIG. 20B, in response to the proper application of the impact force FI to the head 214, the impactor assembly 210 and the implantable component 116 move together along the trajectory T to align the implant reference point IRP (defined by the implantable component 116) with the target reference point TRP (defined at the target site TS).

[0178] Here, the manipulator 102 can be configured to advance the guide 208 along the trajectory T towards the target site TS during the impact of the mallet during impact to return the tool center point TCP (defined by the channel 262 of the guide 208) to alignment with the flange reference point FRP (defined by the flange 216 of the impactor assembly 210). This can be determined, as described above, via the follower sub-assembly 290 and / or the sensor sub-assembly 288, and / or based on the tracked states of the second tool tracker 160I and the first tool tracker 160G, via the navigation system 128. The manipulator 102 may not necessarily be able to advance the guide 208 along the trajectory T, for example, if the axial channel ends 262A, 262B are spaced apart from each other by a distance sufficient to ensure that the flange 216 remains engaged with the channel 262 during impact. This can be advantageous in embodiments where the surgical system 100 can determine the relative position of the flange 216 along the channel 262 with high precision, such as by using a linear variable differential transformer (LVDT) coil arrangement coupled to the tool 104. Embodiments of this type of LVDT coil arrangement are described in the previously referenced U.S. Patent Application Publication No. US2019 / 0231446A1, entitled "End Effectors, Systems, And Methods For Impacting Prosthetics Guided By Surgical Robots". Other configurations are contemplated.

[0179] As described above, the illustrated embodiment of the tool 104 is generally configured to allow translation of the impactor assembly 210 relative to the guide 208 to facilitate engagement of the implantable component 116 with the target site TS. Further, embodiments of the tool 104 are also generally configured to allow rotation of the impactor assembly 210 relative to the guide 208, and / or vice versa, in one or more degrees of freedom. This relative rotation is achieved by bearing-type contact (e.g., sliding contact) that occurs between the first engagement surface 218 and the second engagement surface 270. Here, the ability of the impactor assembly 210 to rotate and translate relative to the guide 208 serves, for example, to prevent a significant amount of force and / or torque from translating from the impactor assembly 210 to the guide 208 (and thus the manipulator 102) during application of the impact force FI. However, a certain amount of force and / or torque is necessarily transferred to the manipulator 102 in one or more degrees of freedom DOF due to the physical contact that occurs between the guide 208 and the impactor assembly 210.

[0180] In FIG. 21A, the impactor assembly 210, the guide 208, the implantable component 116, and the manipulator 102 are generally arranged in the same manner as shown in FIG. 20A, and the second axis A2 (defined by the guide 208) is similarly aligned with the first axis A1 (defined by the impactor assembly 210) and the target site TS (e.g., via coincidence with the trajectory T) of the implantable component 116 arranged to engage the target site TS prior to impact. However, in FIG. 21A, the impact force FI is shown as being inappropriately applied to the head 214 of the impactor assembly 210 (e.g., crossing the trajectory T). Here, an inappropriate application of the impact force FI (e.g., relatively large in magnitude and / or deviated from the trajectory T) may result in the implantable component 116 seating (e.g., partially seating) on the target site TS such that it is misaligned with the trajectory T (e.g., when the first axis A1 and the second axis A2 do not coincide with the trajectory T). Such a hypothetical scenario is shown in FIG. 21B, which shows an exaggerated misalignment between the axes A1, A2 and the trajectory T for illustrative purposes.

[0181] In FIG. 21B, as in the scenario described above in connection with FIGS. 14A - 14D, as a result of the misalignment with the trajectory T, a virtual "runaway" state of the surgical system 100 may occur. Here, the inappropriate application of the impact force FI caused the implantable component 116 to seat at the target site TS in a way that caused misalignment between the first and second axes A1, A2 and the trajectory T. The target state ST of the tool 104 can be defined in several ways for the purposes of illustration in this representative example, but the target state ST includes (or results in) a matching alignment between the second axis A2 and the trajectory T (e.g., by using the tool center point TCP arranged along the trajectory T). However, the current state SC of the tool 104 shown in FIG. 21B includes a misalignment between the second axis A2 and the trajectory T, and since the implantable component 116 is "locked" at the target site TS, a "runaway" state can similarly occur when the manipulator 102 attempts to move from the current state to the target state ST. The "runaway" state can also occur as a result of the patient tracker 160 loosening from the target site TS, thereby causing a loss of tracking accuracy.

[0182] In this illustrative example, as shown by continuously comparing FIGS. 21B - 21D, the movement of the tool 104 to the target state ST (e.g., to return the tool center point TCP to the trajectory T), such as by the guide 208, also results in a corresponding movement of the target site TS, which, as described above, defines the trajectory T (and thus the target state ST) based on the tracking state of the first patient tracker 160A monitored by the navigation system 128. In other words, when the manipulator 102 attempts to move the tool 104 (e.g., the guide 208) from the current state SC to the target state ST (e.g., such that the first and second axes A1, A2 return to simultaneous alignment with the trajectory T), the target site TS moves with the tool 104 and does not reach the target state ST (e.g., simultaneous alignment does not occur). Here too, as shown in FIGS. 21C - 21D, this can thereby potentially cause the target site TS to be "lifted" from the work surface WS ultimately.

[0183] As described above, various techniques for detecting and / or responding to the occurring "runaway" condition are contemplated by the present disclosure, which utilize a tool 104 having an instrument 112, such as a guide 208, to support an impactor assembly 210 to facilitate the engagement of the implantable component 116 with the target site TS (e.g., as described above in connection with FIGS. 18-21D), and for a surgical system 100 that utilizes a tool 104 having an instrument 112, such as described above in connection with FIGS. 12-14D, to facilitate the engagement of the target site TS with an energy applicator 114, such as a powered surgical device 150. For this purpose, the controller 124 can detect the "runaway" condition by monitoring one or more system conditions SYC (e.g., as sensed by the sensing system 206) against one or more predetermined conditions PR (e.g., a first predetermined condition PR1, a second predetermined condition PR2, etc.), as described above and in more detail below.

[0184] As shown above (see Figure 25), the sensing system 206 is configured to detect one or more system conditions SYC related to one or more of the tool 104, the manipulator 102, the target site TS, or combinations thereof. In other words, the sensing system 206 can detect one or more system conditions SYC related to the tool 104, one or more system conditions SYC related to the manipulator 102, and / or one or more system conditions SYC related to the target site TS. For this purpose, in some embodiments, the sensing system 206 may include a sensor 180 for detecting a force FD generated between the target site TS and the manipulator 102. Here, for example, the tracking state of the force FD detected by the sensor 180 can define a system condition SYC used by the controller 124 to facilitate a change in the operation of the manipulator 102 between the first and second modes M1, M2, as will be described in more detail below. In some embodiments, the sensing system 206 may include one or more components of the navigation system 128 (e.g., the localizer 158) and / or one or more trackers 160. Here, for example, the tracking state of the tracker 160 monitored by the localizer 158 can define a system condition SYC used by the controller 124 to facilitate a change in the operation of the manipulator 102 between the first and second modes M1, M2, as will be described in more detail below. Here too, as described above, one or more components of the surgical system 100 can (directly or indirectly) determine the placement of the tool 104 within one or more coordinate systems (e.g., the pose of the tool center point TCP within the localizer coordinate system LCLZ). Here, the placement of the tool 104, as well as changes in the placement of the tool 104 (e.g., movement relative to one or more trackers 160), can define a system condition SYC used by the controller to facilitate a change in the operation of the manipulator 102 between the first and second modes M1, M2, as will be described in more detail below.In some embodiments, the sensing system 206 or sensor 180 may additionally or alternatively include a sensor 180 configured to detect current from any one or more of the actuators of joint J, a sensor that detects one or more torques applied to any one or more of joint J or the joint actuators, or a sensor that detects any other external (such as backdrive) force or torque applied to any one or more joints J. An example of a method for calculating the backdrive force to a joint is described in U.S. Patent No. 10,327,849 entitled "Robotic System and Method for Backdriving The Same", which is incorporated herein by reference. The current measurements obtained by the sensor 180 at any one or more of the actuators of joint J can be converted into force or torque measurements, which can be projected onto the target site TS with which the tool 104 is interacting. In some examples, these force-torque measurements obtained from the joint can be compared to measurements from a six-degree-of-freedom (DOF) force / torque transducer arranged to detect forces and / or torques generated between the manipulator 102 and the target site TS, and state data regarding the patient or tool obtained by the navigation system. The sensing system 206 can include (or otherwise communicate with) various components of the surgical system 100, including, by way of non-limiting example, one or more instruments 112, joint encoders 122, controllers 124, 132, 134, 136, input device 146, output device 144, user interface 142, power generation assembly 152, pointer 156, localizer 158, tracker 160, video camera 170, etc. Other configurations are contemplated.

[0185] System condition SYC can be defined in several different ways, including being based on the relationships between different components of the surgical system 100 and / or the target site TS. For example, the pose of the first patient tracker 160A (e.g., tracked within the localizer coordinate system LCLZ) and the pose of the tool center point TCP of the tool 104 (e.g., transformed or tracked within the localizer coordinate system LCLZ) can each define their respective system conditions SYC, and the simultaneous movement of the pose of the first patient tracker 160A along with the pose of the tool center point TCP of the tool 104 can define different system conditions SYC. Thus, in the present disclosure, several different system conditions SYC are contemplated that can be defined in various ways based on changes occurring in one or more of and / or between the tool 104, the manipulator 102, and / or the target site TS.

[0186] Referring now to FIG. 22A, as described above, the controller 124 is configured to operate the manipulator 102 in a first mode M1 to maintain alignment of the tool 104 with respect to the target site TS based on a first constraint criterion C1, and to operate the manipulator 102 in a second mode M2 to maintain alignment of the tool 104 with respect to the target site TS based on a second constraint criterion C2 that is different from the first constraint criterion C1. For this purpose, in some embodiments, the difference between the first constraint criterion C1 and the second constraint criterion C2 can be based on the degrees of freedom DOF by which the movement of the tool 104 with respect to the target site TS is restricted (or permitted), and how it is affected by movement in one or more degrees of freedom DOF (see also FIG. 25). This concept will be described in more detail below in connection with FIGS. 24A - 24C, but for purposes of illustration, FIG. 22A shows the manipulator 102 supporting the instrument 112 of the tool 104 (here a guide 208) spaced from an impactor assembly 210 secured to an implantable component 116 initially engaged and disposed on the target site TS supported on the work surface WS, with the tool center point TCP of the tool 104 and the target reference point TRP of the target site TS each shown including the six respective degrees of freedom DOF represented in Cartesian form.

[0187] More specifically, the tool center point TCP and the target reference point TRP each define their respective x-position XP degrees of freedom DOF, y-position YP degrees of freedom DOF, z-position ZP degrees of freedom DOF, x-orientation ZO degrees of freedom DOF, y-orientation YO degrees of freedom DOF, and z-orientation ZO degrees of freedom DOF within a common coordinate system (e.g., the localizer coordinate system LCLZ or another suitable coordinate system). Here, the tool center point TCP is "fixed" with respect to the tool 104 and is recognized by the controller 124 (e.g., based on the geometric relationship between the tool 104 and the coupling 110 of the manipulator 102). Similarly, the target reference point TRP is "fixed" with respect to the target site TS and is recognized by the controller 124 (e.g., based on the tracking state of the first patient tracker 160A coupled to the target site TS and defined by reaming the acetabulum). For the sake of explanation, the tool center point TCP and the target reference point TRP are shown as coordinate systems in FIGS. 22A - 24C, and the x, y, and z axes each represent two degrees of freedom DOF, namely, the translation of the coordinate system along the axis in a certain direction and the rotation of the coordinate system in the direction about the axis. In FIG. 22A, for the purpose of explanation, the tool center point TCP is arranged such that its z-axis is parallel to the trajectory T and its x-axis crosses the trajectory T, and the target reference point TRP is arranged such that its z-axis coincides with the trajectory T.

[0188] In some embodiments, the first constraint criterion C1 may include a first number N1 of degrees of freedom DOF by which the movement of the tool 104 is restricted with respect to the target site TS, and the second constraint criterion C2 may include a second number N2 of degrees of freedom DOF by which the movement of the tool 104 is restricted with respect to the target site TS, where the second number N2 of degrees of freedom DOF is different from the first number N1 of degrees of freedom DOF. Thus, in some embodiments, the controller 124 is configured to operate the manipulator 102 to maintain alignment of the tool 104 with respect to the target site TS based on the first number N1 of degrees of freedom DOF in a first mode M1 and based on the (different) second number N2 of degrees of freedom DOF in a second mode M2.

[0189] Here, the first number N1 can represent the number of "active" degrees of freedom DOF that define the target state ST in the first mode M1, and the second number N2 can represent the number of "active" degrees of freedom DOF that define the target state ST of the second mode M2. For example, if the sensing system 206 includes a sensor 180 for detecting the force FD generated between the target site TS and the manipulator 102 to define the system condition SYC, in some embodiments, the controller 124 can define the target state ST based on a total of six degrees of freedom DOF (e.g., x position XP, y position YP, z position ZP, x orientation XO, y orientation YO, and z orientation ZO) for operating the manipulator 102 in the first mode M1. As soon as the force FD detected by the sensor 180 satisfies a predetermined condition PR, it can automatically change how the target state ST is defined for operating the manipulator 102 in the second mode M2 based on three degrees of freedom DOF (e.g., x orientation XO, y orientation YO, and z orientation ZO). Here, the predetermined condition PR can be defined as the force FD detected by the sensor 180 (e.g., the force and / or torque in one or more degrees of freedom DOF), which indicates a potential "runaway" condition defined, for example, by the implantable component 116 being "fixed" to the patient P's anatomical structure at the target site TS. Thereby, the controller 124 effectively changes the target state ST so as not to maintain the position (e.g., x position XP, y position YP, and z position ZP) of the tool center point TCP relative to the target site TS in the second mode M2.

[0190] Accordingly, in some embodiments, the controller 124 operates the manipulator 102 in a first mode M1 to restrict the movement of the tool center point TCP away from the target site TS (or trajectory T) according to a first constraint criterion C1 (e.g., defining a target state ST based on a target direction OT and a target position PT) and based on a first number N1 of degrees of freedom DOF, and operates the manipulator 102 in a second mode M2 to permit the movement of the tool center point TCP away from the target site TS according to a second constraint criterion C2 (e.g., defining a target state ST based on the target direction OT but not based on the target position PT) and based on a (different) second number N2 of degrees of freedom DOF. This illustrative example is described in more detail below in connection with FIGS. 24A-24C, but other configurations are contemplated and the change between modes based on satisfying a predetermined condition PR can occur in several different ways based on various system conditions SYC determined via the sensing system 206.

[0191] In one embodiment, the degrees of freedom DOF of the second number N2 are less than the degrees of freedom DOF of the first number N1, such that as a result, the controller 124 enables movement of the tool 104 relative to the target site TS with at least one more degree of freedom in the second mode M2 than in the first mode M1. Here too, in some embodiments, the first constraint criterion C1 and the second constraint criterion C2 may each include at least one directional degree of freedom DOF (e.g., x-direction XO, y-direction YO, and / or z-direction ZO), the first constraint criterion C1 may include at least one more positional degree of freedom DOF (e.g., x-position XP, y-position YP, and / or z-position ZP) than the second constraint criterion C2, and both the first constraint criterion C1 and the second constraint criterion C2 may include at least one common degree of freedom DOF (e.g., x-direction XO, y-direction YO, and / or z-direction ZO). Further, in some embodiments, the first constraint criterion C1 may include at least one positional degree of freedom DOF (e.g., x-position XP, y-position YP, and / or z-position ZP) and at least one directional degree of freedom DOF (e.g., x-direction XO, y-direction YO, and / or z-direction ZO). However, as will be apparent from the following description, other configurations are contemplated, and the first criterion C1 and / or the second constraint criterion C2 may be defined in several different ways, e.g., depending on the type of surgical procedure being performed at the target site TS, the particular arrangement and configuration of the tool 104 (and / or the energy applicator 114 or the implantable component 116), how the tool 104 is positioned relative to the target site TS by the manipulator 102, and the like.

[0192] In some embodiments, the first constraint criterion C1 may include a first elasticity parameter R1, and the second constraint criterion C2 may include a second elasticity parameter R2 that is different from the first elasticity parameter R1. Thus, in some embodiments, the controller 124 is configured to operate in the first mode M1 to maintain the alignment of the tool 104 with respect to the target site TS based on the first elasticity parameter R1, and in the second mode M2, to operate the manipulator 102 to maintain the alignment of the tool 104 with respect to the target site TS based on the (different) second elasticity parameter R2. Here, the first elasticity parameter R1 can represent or otherwise correspond to an adjustment parameter TPA (e.g., a spring parameter PS and / or a damping parameter PD) of one or more guide constraints GC that define the first mode M1, and the second elasticity parameter R2 can represent or otherwise correspond to an adjustment parameter TPA (e.g., a spring parameter PS and / or a damping parameter PD) of one or more guide constraints GC that define the second mode M2. As will be understood from the subsequent description below, the first constraint criterion C1 and / or the second constraint criterion C2 can be configured or defined in several different ways. For example, by way of non-limiting example, an elasticity parameter is defined for each "active" degree of freedom DOF while operating in either the first mode M1 or the second mode M2. In other words, the first constraint criterion C1 may include three "active" degrees of freedom DOF, each having its own first elasticity parameter, which may be the same as or different from each other. Other configurations are contemplated.

[0193] In some embodiments, the controller 124 may be configured to allow for a more elastic movement of the tool 104 relative to the target site TS in a second mode M2 than in a first mode M1. In other words, a second elasticity parameter R2 is less “rigid” than a first elasticity parameter R1, and it may be more difficult for the first mode M1 than the second mode M2 to deviate from the target state ST. However, other configurations are contemplated. In some embodiments, the first elasticity parameter R1 and the second elasticity parameter R2 are each related to a resilient movement of the tool 104 relative to the target site TS in at least one common degree of freedom DOF (e.g., in an x position XP, a y position YP, a z position ZP, an x direction XO, a y direction YO, or a z direction ZO). As a non-limiting example, the z direction ZO degree of freedom DOF is “active,” and the first and second elasticity parameters R1, R2 are each associated with the z direction ZO degree of freedom DOF and can form part of both a first constraint criterion C1 and a second constraint criterion C2.

[0194] In some embodiments, the first constraint criterion C1, the second constraint criterion C2, and / or the predetermined condition PR may be adjustable and / or configurable by the user via, for example, the user interface 142. For this purpose, a threshold control 314 (see FIG. 2 and also FIG. 25) may be provided to facilitate adjusting how the predetermined condition PR is defined. As an example, the threshold control 314 may be configured as an input device 146 that changes the amount of force FD (e.g., system condition SYC) detected by the sensor 180 required to satisfy the predetermined condition PR, such that, for example, more or less force FD is detected (e.g., force and / or torque in a particular direction) before the controller 124 changes from the first mode M1 to the second mode M2. As a further example, the threshold control 314 may be configured as an input device 146 that changes the time during which the tool 104 and the target site TS move together (as determined, for example, via the navigation system 128) to satisfy the predetermined condition PR, such that, for example, more or less time of co - movement is required before the controller 124 changes from the first mode M1 to the second mode M2. The above examples are illustrative and non - limiting, and other configurations are contemplated.

[0195] In some embodiments, a stiffness control 316 (see FIG. 2 and also FIG. 25) may be provided to facilitate adjusting how the first constraint criterion C1 (or, in some embodiments, the second constraint criterion C2) is defined. As an example, the stiffness control 316 may be configured as an input device 146 that changes the adjustment parameters TPA and / or the configuration parameters CPA of one or more guide constraints GC used to define the first mode M1 (e.g., to facilitate maintaining the target state ST), such that, for example, by increasing or decreasing the first elasticity parameter R1, a change is brought about corresponding to the degree to which the manipulator 102 restricts movement from the target state ST (e.g., with less or more "stiffness"). Again, the foregoing examples are illustrative and non - limiting, and other configurations are contemplated.

[0196] In other implementation forms, the first constraint criterion C1 or the second constraint criterion C2 can be dynamically determined or adjusted based on measurements from the sensing system or sensor 180. The controller can correlate the magnitude or value of the sensed measurement with the value of stiffness, for example, using a look-up table stored in the memory. This approach can be implemented using the above-mentioned threshold or regardless of the threshold.

[0197] In some embodiments, the surgical system 100 also includes a mode indicator 318 (see FIG. 2 and also FIG. 25) coupled to a controller 124 that conveys a change in operation of the manipulator 102 from a first mode M1 to a second mode M2 (or between other modes). Here, the mode indicator 318 can form part of the user interface 142 (for example, as an alarm, speaker, indicator light, part of a display screen, and / or another type of output device 144), and the controller 124 can be configured to activate the mode indicator 318 in response to determining that at least one of one or more system conditions SYC meets a predetermined condition PR.

[0198] As described above, FIG. 22A shows a manipulator 102 supporting an instrument 112 of a tool 104 (here a guide 208) spaced from an impactor assembly 210 fixed to an implantable component 116 initially engaged and disposed on a work surface WS, with the tool center point TCP of the tool 104 and the target reference point TRP of the target site TS being spaced from each other. Comparing FIG. 22A with FIG. 22B shows the movement of the tool 104 in the x-position XP degree of freedom DOF (for example, the direction along the x-axis of the tool center point TCP), whereby the shaft 224 of the impactor assembly 210 passes through the opening 268 of the guide 208 and enters the channel 262, bringing the tool center point TCP to the orbit T (and also onto the z-axis of the target reference point TRP).

[0199] Comparing FIG. 22B with FIG. 22C shows the movement of tool 104 in the z-position ZP degree of freedom DOF (e.g., the direction along the z-axis of the tool center point TCP), whereby the flange 216 of the impactor assembly 210 is disposed within the channel 262 of the guide 208, the first engagement surface 218 is adjacent to the second engagement surface 270, the tool center point TCP is disposed in coincidence with the flange reference point FRP, and still disposed along the trajectory T.

[0200] In some embodiments, the controller 124 may be configured to operate the manipulator 102 in a second mode M2 to enable movement of the tool 104 relative to the target site TS in at least one degree of freedom DOF according to a second constraint criterion C2. Similarly, in some embodiments, the controller 124 may be configured to operate the manipulator 102 in a first mode M1 to enable movement of the tool 104 relative to the target site TS in at least one degree of freedom DOF according to a first constraint criterion C1. Here, for example, comparing FIG. 22C with FIG. 23 shows the movement of the tool 104 in the ZO degree of freedom DOF in the z-direction (e.g., the direction around the z-axis of the tool center point TCP), whereby the guide 208 has moved relative to the impactor assembly 210 and the target site TS from the arrangement shown in FIG. 22C (shown as a phantom outline in FIG. 23), however, the tool center point TCP of the tool 104 remains disposed in coincidence with the flange reference point FRP and is similarly disposed along the trajectory T.

[0201] In other words, the movement of the tool 104 as shown by comparing FIGS. 22C to 23 is such that the first constraint criterion C1 includes five active degrees of freedom DOF (e.g., x position XP, y position YP, z position ZP, x direction XO, and y direction YO), permits movement in one degree of freedom DOF (e.g., Z direction ZO), and defines the target state ST while operating in the first mode M1. This configuration can be implemented, for example, such that the user "rotates" the guide 208 with respect to different arrangements that are maintained by the manipulator 102 (e.g., by redefining the target state ST based on where the guide 208 is placed by the user) for the trajectory T (e.g., the interval of the hammer strike to the head 214 of the impactor assembly 210).

[0202] However, the first constraint criterion C1 can be configured in several different ways to define the target state ST while operating in the first mode M1. For example, rather than enabling the user to adjust the orientation of the guide 208 around the trajectory T of the first mode M1 such that the manipulator 102 redefines the target state ST based on the user "rotating" the guide 208 around the trajectory T, instead, the first constraint criterion C1 can be configured to define the target state ST with all six degrees of freedom DOF while allowing for more elastic movement (e.g., less "stiff" movement) in one or more degrees of freedom DOF than the others. As an illustrative example, the arrangement shown in FIG. 22C can instead represent the target state ST in the first mode M1, and the first constraint criterion C1 is configured such that the first elasticity parameter R1 associated with the z direction ZO degree of freedom DOF has a relatively "weak" value, which value, as shown in FIG. 23, enables the user to "rotate" the guide 208 around the trajectory T but nevertheless urges the tool 104 towards the target state ST. In this case of this example, the arrangement of the tool 104 shown in FIG. 23 represents the current state SC, and the target state ST is shown as a phantom outline (see also FIG. 22C).

[0203] Referring now to FIGS. 24A - 24C, in some embodiments, the controller 124 may be further configured to operate the manipulator 102 in a third mode M3 to maintain alignment of the tool 104 with respect to the target site TS according to a third constraint criterion C3 that is different from both the first constraint criterion C1 and the second constraint criterion C2. Here, in this embodiment, the controller 124 changes the operation of the manipulator 102 from the first mode M1 to the second mode M2 in response to determining that at least one of one or more system conditions SYS satisfies a first predetermined condition PR1, and changes the operation of the manipulator 102 from the second mode M2 to the third mode M3 in response to determining that at least one of one or more system conditions SYS satisfies a second predetermined condition PR2 that is different from the first predetermined condition PR1. Here, in this exemplary embodiment, the first constraint criterion C1 includes a first number N1 of degrees of freedom (DOF) by which the movement of the tool 104 is restricted with respect to the target site TS, the second constraint criterion C2 includes a second number N2 of degrees of freedom (DOF) by which the movement of the tool 104 is restricted with respect to the target site TS, and the third constraint criterion C3 includes a third number N3 of degrees of freedom (DOF) by which the movement of the tool 104 is restricted with respect to the target site TS. Further, in this illustrative embodiment, the first constraint criterion C1 also includes a first elasticity parameter R1, the second constraint criterion C2 also includes a second elasticity parameter R2, and the third constraint criterion C3 also includes a third elasticity parameter R3.

[0204] Accordingly, in the exemplary embodiments shown in FIGS. 24A - 24C, the controller 124 operates the manipulator 102 to maintain the alignment of the tool 104 with respect to the target site TS in a first mode M1 based on a first number N1 of degrees of freedom (DOF) and also based on a first elasticity parameter R1, and in a second mode M2 based on a second number N2 of degrees of freedom (DOF) and also based on a second elasticity parameter R2, and in a third mode M3 is further configured to maintain the alignment of the tool 104 with respect to the target site TS based on a third number N3 of degrees of freedom (DOF) and also based on a third elasticity parameter R3. Here, the third number N3 of degrees of freedom (DOF) is different from one or more of the first number N1 of degrees of freedom (DOF) and the second number N2 of degrees of freedom (DOF). More specifically, in this embodiment, the third number N3 of degrees of freedom (DOF) is less than the first number N1 of degrees of freedom (DOF), such that the controller 124 enables movement of the tool 104 with respect to the target site TS in the third mode M3 with at least one more degree of freedom (DOF) than in the first mode M1. Similarly, in this embodiment, the third number of degrees of freedom (DOF) is less than the second number N2 of degrees of freedom (DOF), such that the controller 124 enables movement of the tool 104 with respect to the target site TS in the third mode M3 with at least one more degree of freedom (DOF) than in the second mode M2.

[0205] More specifically, in this exemplary embodiment, the first number N1 of degrees of freedom (DOF) is equal to the second number N2 of degrees of freedom (DOF), and both are different from the third number N3 of degrees of freedom (DOF). However, other configurations are contemplated. Here, in this embodiment, the difference between the first constraint criterion C1 and the second constraint criterion C2 is not based on the first and second numbers N1, N2 of degrees of freedom (DOF) that are "active" in the first and second modes M1, M2, but rather is based on the first and second elasticity parameters R1, R2 as will be explained in more detail below.

[0206] In some embodiments, such as the embodiments shown in connection with FIGS. 24A - 24C, the first constraint criterion C1 and the second constraint criterion C2 each include at least one position degree of freedom DOF (e.g., x - position XP, y - position YP, and / or z - position ZP) and at least one direction degree of freedom DOF (e.g., x - direction XO, y - direction YO, and / or z - direction ZO), and each of the first constraint criterion C1, the second constraint criterion C2, and the third constraint criterion C3 includes at least one direction degree of freedom (e.g., x - direction XO, y - direction YO, and / or z - direction ZO). Here too, the first constraint criterion C1 and the second constraint criterion C2 each include at least one more position degree of freedom DOF than the third constraint criterion C3. However, other configurations are contemplated.

[0207] As described above, in the exemplary embodiments shown in FIGS. 24A - 24C, the difference between the first constraint criterion C1 and the second constraint criterion C2 is based on the first and second elastic parameters R1, R2 rather than the degrees of freedom DOF of the first and second numbers N1, N2 that are “active” in the first and second modes M1, M2. Here, the third elastic parameter R3 is different from one or more of the first elastic parameter R1 and the second elastic parameter R2, and these are also different from each other in this embodiment. More specifically, as will be described in more detail below, the controller 124 enables a more elastic movement (e.g., a less “stiff” movement) of the tool 104 with respect to the target site TS in the second mode M2 than in the first mode M1, and enables a more elastic movement (e.g., a less “stiff” movement) of the tool 104 with respect to the target site TS in the second mode M2 than in the third mode M3. Here too, the above is intended to be a non - limiting example, and other configurations of the surgical system 100 are contemplated.

[0208] In FIG. 24A, the controller 124 operates the manipulator 102 in the first mode M1 in accordance with the first constraint criterion C1. In this exemplary embodiment, the tool 104 is arranged such that the alignment with the trajectories T of the axes A1 and A2 as described above is performed to define the target state ST as shown in the figure. For this purpose, the first constraint criterion C1 includes both the first number N1 of degrees of freedom DOF and the first elasticity parameter R1. For the purpose of this illustrative example, the first number N1 includes six "active" degrees of freedom DOF, namely the x position XP, the y position YP, the z position ZP, the x direction XO, the y direction YO, and the z direction ZO. Further, in this illustrative example, the first elasticity parameter R1 is defined by the adjustment parameter TPA of the guide constraint GC, which is set relatively high, for example, so that the spring parameter PS resists the movement in each of the six active degrees of freedom DOF, and is set to maintain the tool 104 in the target state ST with a relatively "hard tactile".

[0209] Continuing to refer to FIG. 24A, it is shown that the impact force FI is being inappropriately applied to the head 214 of the impactor assembly 210 (e.g., crossing the trajectory T). Here, an inappropriate application of the impact force FI (e.g., relatively large and / or off the trajectory T) can result in the implantable component 116 partially seating in the target site TS in a manner that is off the trajectory T, which, for illustrative purposes, is shown in FIG. 24B with an exaggerated misalignment between the axes A1, A2 and the trajectory T. Here, in FIG. 24B, the sensor 180 detects a force FD between the target site TS and the manipulator 102 resulting from the deviation of the illustrated current state SC from the target state ST (here shown as a phantom contour), and the sensor 180 functions as part of the sensing system 206 to detect a system condition SYC (e.g., the force FD). In this scenario, rather than continuing to move the manipulator 102 to return the tool 104 to the target state ST (e.g., by returning the tool center point TCP to the trajectory T), in response to the force FD being detected by the sensor 180 satisfying a first predetermined condition PR1, the controller 124 changes from a first mode M1 to a second mode M2, which, in this embodiment, is defined as a first force F1 detected by the sensor 180 (e.g., force and / or torque in one or more degrees of freedom DOF). Thus, FIG. 24B shows the operation of the manipulator 102 in a second mode M2 according to a second constraint criterion C2.

[0210] In FIG. 24B, the controller 124 is operating the manipulator 102 in a second mode M2 according to a second constraint criterion C2, and the target state ST is still defined by the arrangement shown in FIG. 24A (shown as a phantom contour in FIG. 24B). Here, the second constraint criterion C2 includes the number N2 of second degrees of freedom DOF and the second elasticity parameter R2. For the purpose of this illustrative example, the second number N2 includes six “active” degrees of freedom DOF, namely the x position XP, the y position YP, the z position ZP, the x direction XO, the y direction YO, and the z direction ZO. However, in this illustrative example, the second elasticity parameter R2 is set such that the tool 104 is urged toward the target state ST with a relatively “loose haptic” (e.g., the second elasticity parameter R2 is smaller than the first elasticity parameter R1) defined, for example, by the adjustment parameter TPA of the guide constraint GC, and in this case the spring parameter PS is set relatively low, allowing a certain amount of elastic movement in each of the six active degrees of freedom DOF. In this configuration, although the manipulator 102 is still trying to return to the target state ST (e.g., by returning the tool center point TCP to the trajectory T), the “loose haptic” provided by the second constraint criterion C2 allows a certain amount of deviation from the target state ST to occur, thereby preventing the “escaping” state when the implantable component 116 is partially seated in the target site TS while being displaced, and keeping the target site TS supported on the work surface WS.

[0211] Continuing to refer to FIG. 24B, it is shown that an additional impact force FI is being inappropriately applied to the head 214 of the impactor assembly 210 (e.g., crossing the trajectory T). Here, an inappropriate application of the impact force FI (e.g., relatively large and / or offset from the trajectory T) can still result in the implantable component 116 seating at the target site TS in a manner that is further offset from the trajectory T, which is shown in FIG. 24C with an exaggerated mismatch between the axes A1, A2 and the trajectory T for illustrative purposes. Here in FIG. 24C, the sensor 180 similarly detects a force FD between the target site TS and the manipulator 102 resulting from a further deviation of the illustrated current state SC from the target state ST (shown here as the end point of the trajectory T). Also at this point in this scenario, rather than continuing to move the manipulator 102 to return the tool 104 to the target state ST (e.g., by returning the tool center point TCP to the trajectory T), in response to the force FD being detected by the sensor 180 satisfying a second predetermined condition PR2, the controller 124 changes from the second mode M2 to the third mode M3, which in this embodiment is defined as a second force F2 detected by the sensor 180 (e.g., a force and / or torque in one or more degrees of freedom DOF), and the second force F2 is greater than the first force F1. In some embodiments, the second force F2 may be less than the amount of force and / or torque acting on the target site TS in one or more directions through engagement with the implantable component 116 that could otherwise become a partially or fully “detaching” implantable component 116.

[0212] In FIG. 24C, the controller 124 operates the manipulator 102 in a third mode M3 according to a third constraint criterion C3, and the target state ST is still defined in the arrangement shown in FIG. 24A (shown as the end point of the trajectory T in FIG. 24C). Here, the third constraint criterion C3 includes the number N3 of the third degrees of freedom DOF and the third elasticity parameter R3. For the purpose of this illustrative example, the third number N3 includes three “active” degrees of freedom DOF, namely, the x-direction XO, the y-direction YO, and the z-direction ZO. In other words, according to the third constraint criterion C3, the position degrees of freedom DOF are not active. Here, in this illustrative example, the third elasticity parameter R3 is defined by an adjustment parameter TPA of a guide constraint GC that is set relatively high, for example, so that a spring parameter PS resists the movement in each of the three active degrees of freedom DOF, and is set so that the tool 104 is driven toward the target state ST with a relatively “hard touch”. Here, the tool 104 is urged toward the target state ST based on direction rather than position. In this configuration, although the manipulator 102 still attempts to return to the target state ST (for example, by directing the tool center point TCP toward the target site TS), the lack of active position degrees of freedom DOF prevents a “runaway” state from occurring when the implantable component 116 seats further in the target site TS while being misaligned, and the target site TS remains supported on the work surface WS as well. Here, a surgeon or another user can be warned about the change to the third mode M3 via a mode indicator 318 that can form part of one or more user interfaces 142 as described above. As a non-limiting example, when the controller 124 switches from the first mode M1 to the second mode M2, a “low-level” alert (for example, a sound played by a speaker, a warning displayed by a flashing light, or a graphic displayed on a screen, etc.) can be generated to warn the user, and when the controller 124 switches from the second mode M2 to the third mode M2 (or from the first mode M1 to the third mode M3), a different or “high-level” alert can be generated to warn the user.Alerts can be defined in a variety of ways sufficient to distinguish them from each other (e.g., one is visual and the other is auditory, or a combination thereof), and as described above, the mode indicator 318 can be of several different styles, types, and / or configurations.

[0213] With reference to FIGS. 24A - 24C, the representative embodiment described above uses three constraint criteria C1, C2, C3, three modes M1, M2, M3, and two predetermined conditions PR1, PR2, but a similar function can provide two modes and one predetermined condition PR in some embodiments. As a non - limiting example, when using sensor 180 to monitor a system condition SYC defined as a detected force FD (e.g., force and / or torque in one or more degrees of freedom DOF) for a predetermined condition PR, and controller 124 is configured to switch from a first mode M1 (e.g., to maintain six degrees of freedom DOF according to the first constraint criterion C1) to a second mode M2 (e.g., to maintain only the directional degrees of freedom DOF according to the second constraint criterion C2), controller 124 can be configured to operate manipulator 102 in the first mode M1 to resist the movement of tool 104 towards the target site TS while increasing elasticity as the force FD detected by sensor 180 increases towards the predetermined condition PR. In other words, FIG. 24B does not show operation in a mode different from that shown in FIG. 24A, but instead can represent a part of the same mode (e.g., the first mode M1) where the first constraint criterion C1 includes an elasticity parameter. This can be defined as a function of the force FD detected by sensor 180 until the detected force FD meets the predetermined condition PR (e.g., when the force FD exceeds the second force F2 described above in relation to FIG. 24C). However, the preceding examples are illustrative and non - limiting, and other configurations are contemplated.

[0214] In an embodiment that utilizes sensor 180 as part of sensing system 206 to facilitate changes between modes (e.g., first mode M1 and second mode M2), sensor 180 can be further defined as a force torque sensor 180 configured to detect a force FD (e.g., force and / or torque) generated between manipulator 102 and target site TS in one or more degrees of freedom DOF. For this purpose, and as generally shown in FIGS. 1 and 15, sensor 180 can be coupled to robotic arm 108 (e.g., as part of coupling 110). However, sensor 180 can be arranged in any suitable manner sufficient to detect force FD generated between manipulator 102 and target site TS and can be of several different types, styles, or configurations without departing from the scope of the present disclosure. As a non-limiting example, sensor 180 can be implemented as part of coupling 110, as part of robotic arm 108 (e.g., disposed at one of the joints), and / or as part of tool 104 (e.g., disposed on instrument 112 and / or implantable component 116). Similarly, sensor 180 can be disposed on mount 148 and / or on body 260 of guide 208. Further, the representative embodiments shown herein are directed to a single multiple degree of freedom DOF force torque transducer coupled to manipulator 102, but sensor 180 can also be implemented by multiple components disposed at the same location or different locations (e.g., one on guide 208 and another on coupling 110) that cooperate to facilitate detection of force FD generated between target site TS and robotic arm 108. Other configurations are contemplated.

[0215] In some embodiments, the amount of force FD detected by sensor 180 that meets a predetermined condition PR (e.g., a first force F1, a second force F2, or other value) represents or is based on the amount of torque (or force) applied to implantable component 116. Here, using the known characteristics of tool 104 and implantable component 116, the force / torque at sensor 180 can be associated with the force / torque applied at implantable component 116. The calculation of the rigid body Jacobian from sensor 180 to implantable component 116 can be performed according to FIMPLANT = JSENSOR_TO_IMPLANT - T * FSENSOR. The force FD detected by sensor 180 can define the predetermined condition PR in several different ways and can be specific to the application and / or procedure. In some embodiments, the type, style, size, or other parameters of implantable component 116 can at least partially define one or more predetermined conditions PR. Here, for example, a relatively "large" implantable component 116 may require a different amount of torque (or force) applied to it before becoming prone to detachment at the target site TS compared to a relatively "small" implantable component 116. The specific parameters of the predetermined condition PR based on sensor 180 (e.g., the magnitude of force and / or torque in one or more degrees of freedom DOF) can be determined in other ways including by experimentation. For example, the lever-out torque was analyzed for the acetabular cup when determining the baseline force at which the translational constraints of the impact assembly 210 begin to be released. By knowing approximately the torque at which a well-fixed cup 116 is likely to move or detach, the accuracy of the cup placement can be optimized while avoiding lever-out of the cup by releasing the constraints within the specified limits or ranges. With the lever-out strength of the cup 116 in the range of about 5 to 25 Nm, the force limits possible with the impact assembly 210 can be in the range of 20 N to 100 N (assuming a lever arm of 0.25 m from the end effector attachment to the cup center) to accommodate various cup fixation scenarios.In one implementation, the amount of force FD to meet the predetermined condition PR for each laboratory evaluation is approximately 64 N (lever output torque of approximately 16 Nm). However, depending on the cup type, press fit, test method, and material, other values or ranges of values may be considered or are possible. In other examples, the amount of force FD to meet the predetermined condition PR is between 58 - 66 N, 50 - 70 N, or 40 - 80 N, or any value between these ranges.

[0216] In some embodiments, the threshold control 314 (and / or stiffness control 316) can be manually adjusted by the user during the procedure based on subjective considerations, observations, etc. (e.g., a specific predetermined condition PR can be adjusted higher or lower according to the user's preference). In some embodiments, the predetermined condition PR can be based on patient-specific data (e.g., height, weight, age, bone density, body mass index BMI, etc.), and this data can be input using the input device 146 of the user interface 142. In some embodiments, the predetermined condition PR can be at least partially determined during the procedure by, for example, a "wiggle test" similar to that described in U.S. Patent Application Publication No. 2015 / 0094736A1 titled "System and Method of Controlling a Robotic System for Manipulating Anatomy of a Patient During a Surgical Procedure". The disclosure of which is hereby incorporated by reference in its entirety. However, other configurations are contemplated.

[0217] In other implementations, the first constraint criterion C1 or the second constraint criterion C2 can be dynamically determined or adjusted based on measurements from the sensing system or sensor 180. The controller can associate the magnitude or value of the detected measurement with a stiffness value, for example, using a look-up table stored in the memory. This approach can be implemented using the above thresholds or regardless of the thresholds.

[0218] As described above, the functions provided by the surgical system 100 in switching between the first mode and the second modes M1, M2 (and / or other modes) can be performed using (and / or in addition to) other components of the sensing system 206 other than the sensor 180. As a non-limiting example, and referring again to FIGS. 24A-24C, the localizers 158 and one or more trackers 160 (e.g., the first patient tracker 160A and the second tool tracker 160I) can be utilized to monitor system conditions SYC, such as the simultaneous movement of the impactor assembly 210 with the target site TS in a manner that satisfies a predetermined condition PR. Here, the movement that satisfies one or more predetermined conditions PR can be based on various combinations of duration and direction, for example, a movement suggesting that the impactor assembly 210 is "fixed" to the target site TS having a mismatch between the first axis A1 and the trajectory T, a movement suggesting that the target site TS is being lifted from the working surface WS, or a movement suggesting that the target site TS is moving in an unintended direction. Here, the combination of components of the sensing system 206 can be used together such that satisfying a predetermined condition PR to effect a change between the modes M1, M2 requires a plurality of predetermined conditions PR that are satisfied based on the same or different types of system conditions SYC. As a non-limiting example, the sensor 180 can be used to detect when the user is applying an impact force FI and can change the defined manner of a predetermined condition PR for a period including the impact event, for example, to more easily interpret the movement of the target site TS via the first patient tracker 160A during impact in a different manner to prevent false detection of a "runaway" condition when the target site TS first responds to the application of the impact force FI. Other configurations are contemplated.

[0219] Surgical system 100 can detect an impact force FI (or axial external force) and can ignore or downplay such an impact force FI for a runaway state control algorithm. By doing so, surgical system 100 can identify that the event is an impact force FI that is expected and not an undesirable "runaway" state. Next, surgical system 100 can determine that it is not necessary to control the manipulator according to the second mode M2. In one example, to distinguish between the runaway state and the impact force FI, system 100 analyzes the X and Y component force signals from the force torque sensor 180. Since the force in the Z-axis is not restricted by the mechanical design, the force in the Z-component is ignored. In one implementation, to detect the runaway state, system 100 can average the magnitude of the combined X-axis and Y-axis forces over a specific period (e.g., 125 milliseconds) and determine whether this average magnitude of the force is greater than a force threshold. The standard deviation for the same period can be calculated to determine whether the same period is below the threshold. If the threshold is met, system 100 can determine that a runaway state exists. In one experiment, an example of the deviation of the X and Y direction forces in the runaway state was in the range of + / -10 to 60 N. There may be other ways to determine that a runaway state exists. For example, the measured X and Y forces can be compared individually with the threshold limit over time. Other factors can be considered when determining the threshold for detecting the runaway state.

[0220] On the other hand, in order to detect the impact force FI (as compared to the runaway state), the X, Y, and Z components of the force acquired by the sensor 180 can be analyzed by the sensing system 100 over the period during which the impact occurs (e.g., 30 - 60 seconds). In one example, most of the force during the impact event occurs in the Z direction due to the mechanical properties of the assembly. However, the X and Y forces occur depending on the way the user strikes the impactor or the accuracy. During this period, each of the X, Y, and Z components generates an individual signal spike indicating each impact. The sensing system 100 can separate each of the signal spikes indicating each impact. In one example, each signal spike was experimentally determined to last for a duration within the range of 100 - 150 milliseconds. Next, the sensing system 100 can calculate the duration of each impact event and calculate the standard deviation during that calculated duration. From this, a threshold value for defining the impact event is set. When the threshold value is met, the system 100 can determine that an impact event has occurred. In one experiment, examples of the deviation of the force in the X and Y directions in response to the impact event were in the range of + / - 10 - 30 N, and examples of the deviation of the force in the Z direction in response to the impact event were in the range of + / - 20 - 40 N. There may be other ways to determine that an impact event has occurred. For example, the measured force can be compared individually with the threshold value over time. Also, the threshold value for detecting the runaway state may vary depending on factors such as the type of cup, the size of the cup, patient data, the parameters of the impactor, the expected impact force, etc. The system 100 can filter between the runaway and the impact event, and can intelligently change the constraint criteria only when necessary to cancel out the runaway state.

[0221] Furthermore, combining different types of predetermined conditions PR that should be satisfied before changing between modes M1 and M2 can also be implemented using other types of tools 104, such as the powered surgical device 150 described above in connection with FIGS. 12-14D. For example, a predetermined condition PR related to a system condition SYC defined by the operation of the power generation assembly 152 (e.g., motor speed, load, etc.) can be compared with a predetermined condition PR related to a system condition SYC defined by the navigation system 128, sensor 180, etc. For example, in another case, even when the tool 104 and the target site TS that change between modes M1 and M2 move simultaneously, if the energy applicator 114 is still rotating, the change between modes M1 and M2 is avoided. Again, the above examples are intended to be illustrative and non-limiting, and other configurations are contemplated.

[0222] In one example, as shown in FIG. 26, the "runaway" state can exist when a tool 104, such as a tool having a bar 154 as the energy applicator 114, engages the bone of the target site TS while being constrained by a virtual boundary 174 associated with the target site TS. More specifically, a runaway state can exist when the bar 154 is confined, placed, or sandwiched between the virtual boundary 174 and the bone of the target site TS. As a result of this situation, the bar 154 may be partially pushed outside the virtual boundary 174. Since the virtual boundary 174 is configured to limit the movement of the tool 104, the system controls the manipulator to apply a reaction force RF to the bar 154. Due to this reaction force RF, the bar 154 is pressed against the bone of the target site TS, and the bone of the target site TS moves. The target site TS is tracked by a navigation system via a tracker 160A. Thus, pushing the target site TS causes a corresponding movement of the associated virtual boundary 174, and then the reaction force RF persists until the runaway state. Implementations of the systems, methods, and techniques described above can be fully applied to prevent this scenario. In this example, the first constraint criterion C1 and the second constraint criterion C2 can be made as described above to prevent the runaway state. Additionally or alternatively, the constraint criteria C1, C2 can be related to the magnitude or direction of the reaction force RD, the stiffness or damping parameters associated with the reaction force RF, the shape of the virtual boundary 174, the flexibility of the virtual boundary 174, the stiffness or damping parameters related to the direction of the tool 104 and / or the energy applicator 114, or the degrees of freedom of the effective position or direction of the tool 104 and / or the energy applicator 114.

[0223] In one embodiment, the present disclosure also relates to a method of operating a surgical system 100, the surgical system including an impactor assembly 210 having an interface 212 for releasably securing an implantable component 116, a guide 208 having a channel 262 formed to receive the impactor assembly 210, a manipulator 102 configured to support the guide 208 with respect to a target site TS along a trajectory T, a sensor 180, and a controller 124 coupled to the manipulator 102 and the sensor 180 and configured to perform different steps. The steps include operating the manipulator 102 in a first mode M1 to maintain alignment of the guide 208 with respect to the trajectory T according to a first constraint criterion C1, operating the manipulator 102 in a second mode M2 to maintain alignment of the guide 208 with respect to the trajectory T according to a second constraint criterion C2 different from the first constraint criterion C1, detecting, using the sensor 180, a force FD generated between the target site TS and the manipulator 102, and determining that the force FD detected by the sensor 180 satisfies a predetermined condition PC, and accordingly changing the operation of the manipulator 102 from the first mode M1 to the second mode M2.

[0224] Thus, the techniques, methods, and embodiments of the surgical system 100 of the present disclosure provide important advantages in connection with various types of surgical procedures performed using the manipulator 102 to support different types of tools 104 with respect to the target site TS. The functions provided by the controller 124, the sensing system 206, and the manipulator 102 help ensure that surgeons and other users can perform surgical procedures in a safe, reliable, and predictable manner. Specifically, the ability to switch between modes M1, M2 in response to detecting different types of system conditions SYC that satisfy a predetermined condition PR helps prevent "runaway" conditions (and other undesirable movements of different types of tools 104) that would otherwise "lift" or "rotate" the patient P via the manipulator 102.

[0225] Those skilled in the art will understand that the aspects of the embodiments described and illustrated herein can be exchanged or otherwise combined.

[0226] Furthermore, it will be understood that the terms "include", "includes", and "including" have the same meaning as the term "comprise", "comprises", and "comprising". Further, in this specification, terms such as "first", "second", "third", etc. are used to distinguish specific structural features and components for non-limiting and illustrative purposes of clarity and consistency.

[0227] In the foregoing configuration, several embodiments have been described. However, the configurations discussed in this specification are not intended to be exhaustive or to limit the invention to any specific form. The terms used are intended to be of an explanatory nature rather than limiting. In light of the above teachings, many modifications and variations are possible, and the invention can be practiced otherwise than as specifically described. The following is an appended note exemplifying an embodiment of the present invention. (Appended Note 1) A tool for engaging a target site, A manipulator configured to support the tool, A sensing system configured to detect one or more system conditions related to one or more of the tool, the manipulator, the target site, or a combination thereof, A controller coupled to the manipulator and the sensing system, A first mode for maintaining alignment of the tool with respect to the target site according to a first constraint criterion, A second mode for maintaining alignment of the tool with respect to the target site according to a second constraint criterion different from the first constraint criterion A controller configured to operate the manipulator between including, The controller is further configured to change the operation of the manipulator from the first mode to the second mode in response to determining that at least one of the one or more system conditions meets a predetermined condition. A surgical system. (Appended Note 2) The first constraint criterion includes a first number of degrees of freedom in which the movement of the tool is restricted with respect to the target site, and the second constraint criterion includes a second number of degrees of freedom in which the movement of the tool is restricted with respect to the target site, and the second number of degrees of freedom is different from the first number of degrees of freedom, The controller is further configured to operate the manipulator, In the first mode, based on the first number of degrees of freedom, maintain alignment of the tool with respect to the target site, In the second mode, based on the second number of degrees of freedom, maintain alignment of the tool with respect to the target site The surgical system according to appended note 1, which is configured as (Appended Note 3) The second number of degrees of freedom is less than the first number of degrees of freedom, and the controller enables movement of the tool relative to the target site with at least one more degree of freedom in the second mode than in the first mode, the surgical system according to appended note 2. (Appended Note 4) The surgical system according to any one of appended note 2 or 3, wherein the first constraint criterion includes at least one position degree of freedom and at least one direction degree of freedom. (Appended Note 5) The surgical system according to any one of appended note 2 to 4, wherein the first constraint criterion and the second constraint criterion each include at least one direction degree of freedom. (Appended Note 6) The surgical system according to any one of appended note 2 to 5, wherein the first constraint criterion includes at least one more position degree of freedom than the second constraint criterion. (Appended Note 7) The surgical system according to any one of appended note 2 to 6, wherein the first constraint criterion and the second constraint criterion include at least one common degree of freedom. (Appended Note 8) The first constraint criterion includes a first elasticity parameter, the second constraint criterion includes a second elasticity parameter different from the first elasticity parameter, and the controller further operates the manipulator to in the first mode, maintain alignment of the tool relative to the target site based on the first elasticity parameter, and in the second mode, be configured to maintain alignment of the tool relative to the target site based on the second elasticity parameter, the surgical system according to any one of appended note 1 to 7. (Appended Note 9) The surgical system according to appended note 8, wherein the controller enables more elastic movement of the tool relative to the target site in the second mode than in the first mode. (Appended Note 10) The surgical system according to appended note 8 or 9, wherein the first elasticity parameter and the second elasticity parameter are each related to elastic movement of the tool relative to the target site in a common degree of freedom. (Appended Note 11) The tool defines a tool center point, and the controller is configured to operate the manipulator in the first mode to restrict movement of the tool center point away from the target site according to the first constraint criterion, the surgical system according to any one of appended note 1 to 10. (Appended Note 12) The surgical system according to appended note 11, wherein the controller is configured to operate the manipulator in the second mode so as to enable movement of the tool center point away from the target site according to the second constraint criterion. (Appended note 13) The surgical system further includes a mode indicator coupled to the controller, The surgical system according to any one of appended notes 1 to 12, wherein the controller is configured to activate the mode indicator in response to determining that at least one of the one or more system conditions satisfies the predetermined condition, and to notify the user of the change of the operation mode of the manipulator from the first mode to the second mode. (Appended note 14) The surgical system according to any one of appended notes 1 to 13, wherein the controller is configured to operate the manipulator in the first mode so as to enable movement of the tool relative to the target site in at least one degree of freedom according to the first constraint criterion. (Appended note 15) The surgical system according to appended note 14, wherein the controller is configured to operate the manipulator in the second mode so as to enable movement of the tool relative to the target site in at least one degree of freedom according to the second constraint criterion. (Appended note 16) The controller is further configured to operate the manipulator in a third mode that maintains alignment of the tool with respect to the target site according to a third constraint criterion different from both the first constraint criterion and the second constraint criterion, The predetermined condition is further defined as a first predetermined condition, The surgical system according to any one of appended notes 1 to 15, wherein the controller is further configured to change the operation of the manipulator from the second mode to the third mode in response to determining that at least one of the one or more system conditions satisfies a second predetermined condition different from the first predetermined condition. (Appended note 17) The first constraint criterion includes a first number of degrees of freedom by which the movement of the tool is restricted with respect to the target site, the second constraint criterion includes a second number of degrees of freedom by which the movement of the tool is restricted with respect to the target site, the third constraint criterion includes a third number of degrees of freedom by which the movement of the tool is restricted with respect to the target site, and the third number of degrees of freedom is different from one or more of the first number of degrees of freedom and the second number of degrees of freedom. The controller is further configured to operate the manipulator to In the first mode, maintain alignment of the tool with respect to the target site based on the first number of degrees of freedom. In the second mode, maintain alignment of the tool with respect to the target site based on the second number of degrees of freedom. The surgical system according to appendix 16, configured to maintain alignment of the tool with respect to the target site based on the third number of degrees of freedom in the third mode. (Appendix 18) The first constraint criterion further includes a first elasticity parameter, the second constraint criterion further includes a second elasticity parameter, and the third constraint criterion further includes a third elasticity parameter different from one or more of the first elasticity parameter and the second elasticity parameter. The controller is further configured to operate the manipulator to In the first mode, maintain alignment of the tool with respect to the target site based on the first number of degrees of freedom and based on the first elasticity parameter. In the second mode, maintain alignment of the tool with respect to the target site based on the second number of degrees of freedom and based on the second elasticity parameter. The surgical system according to appendix 17, configured to maintain alignment of the tool with respect to the target site based on the third number of degrees of freedom and based on the third elasticity parameter in the third mode. (Appendix 19) The third number of degrees of freedom is less than the first number of degrees of freedom, and the controller enables movement of the tool with respect to the target site with at least one more degree of freedom in the third mode than in the first mode. The surgical system according to appendix 18. (Appendix 20) The third degree of freedom is less than the second degree of freedom, and the controller enables movement of the tool relative to the target site with at least one more degree of freedom in the third mode than in the second mode, the surgical system according to appended note 19. (Appended note 21) The first constraint criterion and the second constraint criterion each include at least one position degree of freedom and at least one direction degree of freedom, the surgical system according to any one of appended notes 18 to 20. (Appended note 22) The first constraint criterion, the second constraint criterion, and the third constraint criterion each include at least one direction degree of freedom, the surgical system according to any one of appended notes 18 to 21. (Appended note 23) The first constraint criterion includes at least one more position degree of freedom than the third constraint criterion, the surgical system according to any one of appended notes 18 to 22. (Appended note 24) The second constraint criterion includes at least one more position degree of freedom than the third constraint criterion, the surgical system according to appended note 23. (Appended note 25) The controller enables a more elastic movement of the tool relative to the target site in the second mode than in the first mode, the surgical system according to any one of appended notes 18 to 24. (Appended note 26) The controller enables a more elastic movement of the tool relative to the target site in the second mode than in the third mode, the surgical system according to appended note 25. (Appended note 27) The first constraint criterion includes a first elasticity parameter, the second constraint criterion includes a second elasticity parameter, and the third constraint criterion includes a third elasticity parameter different from one or more of the first elasticity parameter and the second elasticity parameter, The controller is further configured to operate the manipulator to in the first mode, maintain alignment of the tool relative to the target site based on the first elasticity parameter, in the second mode, maintain alignment of the tool relative to the target site based on the second elasticity parameter, in the third mode, maintain alignment of the tool relative to the target site based on the third elasticity parameter, the surgical system according to any one of appended notes 16 to 26. (Appended note 28) The sensing system includes at least one sensor configured to obtain a measurement indicating a force generated between the target site and the manipulator, the measurement indicating the force obtained by the at least one sensor defines at least one of the one or more system conditions, and the controller operates the manipulator, in response to determining that the force detected by the at least one sensor satisfies the first predetermined condition, from the first mode to the second mode, and in response to determining that the force detected by the at least one sensor satisfies the second predetermined condition, from the second mode to the third mode, the surgical system according to any one of appendices 16 to 27. (Appendix 29) The first predetermined condition is defined by a first force detected by the at least one sensor, the second predetermined condition is defined by a second force detected by the at least one sensor, and the second force is greater than the first force, the surgical system according to appendix 28. (Appendix 30) further includes a patient tracker adapted for attachment to the target site, the sensing system includes a navigation system configured to track the state of the patient tracker, the tracking state of the patient tracker defines at least one of the one or more system conditions, and in response to a determination that the tracking state of the patient tracker satisfies the predetermined condition, the controller changes the operation of the manipulator from the first mode to the second mode, the surgical system according to any one of appendices 1 to 29. (Appendix 31) the controller is further configured to compare the tracked movement of the tool with the movement of the patient tracker based on the tracking state received from the navigation system, the tracked movement of the tool defines at least one of the one or more system conditions, the predetermined condition is defined based on the tracked movement of the tool corresponding to the tracked state of the patient tracker, the surgical system according to appendix 30. (Appendix 32) The sensing system comprises at least one sensor configured to obtain a measurement indicative of a force generated between the target site and the manipulator. The measurement indicative of the force obtained by the at least one sensor defines at least one of the one or more system conditions, and the controller is configured to change the operation of the manipulator from the first mode to the second mode in response to determining that the force detected by the at least one sensor satisfies the predetermined condition. The surgical system according to any one of Appendices 1 to 31. (Appendix 33) The controller is further configured to operate the manipulator in the first mode such that as the measurement indicative of the force obtained by the at least one sensor increases towards the predetermined condition, with an increase in elasticity, it resists the movement of the tool relative to the target site. The surgical system according to Appendix 32. (Appendix 34) The tool includes a guide having a channel formed to receive an impactor assembly and to allow limited movement of the impactor assembly relative to the guide. The impactor assembly has an interface for releasably fixing a prosthesis. The manipulator is configured to support the guide along a trajectory relative to the target site while the impactor assembly is received in the channel of the guide and the prosthesis is fixed to the impactor assembly. The target site is further defined as an acetabular cup. The at least one sensor is configured to detect the force resulting from the force applied to the impactor assembly for installing the prosthesis in the acetabular cup. The controller is further configured to estimate the torque applied to the acetabular cup based on the detected force. The controller is further configured to change the operation of the manipulator from the first mode to the second mode in response to determining that the estimated torque applied to the acetabular cup satisfies the predetermined condition. The surgical system according to any one of Appendices 32 or 33. (Appendix 35) The at least one sensor is further defined as one or more of a force torque transducer, a joint actuator current sensor, a joint force sensor, a joint torque sensor, and a joint encoder, and the surgical system according to any one of Appendices 28, 29, and 32 to 34. (Appendix 36) A tool for engaging a target site along a trajectory, A manipulator configured to support the tool, At least one sensor configured to obtain a measurement indicating a force generated between the target site and the manipulator, A controller coupled to the manipulator and the at least one sensing system, A first mode for maintaining alignment of the tool with respect to the trajectory according to a first constraint criterion, A second mode for maintaining alignment of the tool with respect to the trajectory according to a second constraint criterion different from the first constraint criterion And a controller configured to operate the manipulator between Including, The controller is further configured to change the operation of the manipulator from the first mode to the second mode in response to determining that the force satisfies a predetermined condition, and the surgical system. (Appendix 37) The first constraint criterion includes a first number of degrees of freedom by which the movement of the tool is restricted with respect to the trajectory, the second constraint criterion includes a second number of degrees of freedom by which the movement of the tool is restricted with respect to the trajectory, and the second number of degrees of freedom is different from the first degree of freedom, The controller is further configured to operate the manipulator, In the first mode, maintain alignment of the tool with respect to the trajectory based on the first number of degrees of freedom, In the second mode, maintain alignment of the tool with respect to the trajectory based on the second number of degrees of freedom, and the surgical system according to Appendix 36. (Appendix 38) The second number of degrees of freedom is less than the first number of degrees of freedom, and the controller enables movement of the tool with respect to the trajectory with at least one more degree of freedom in the second mode than in the first mode, and the surgical system according to Appendix 37. (Appendix 39) The surgical system according to any one of Appendices 37 or 38, wherein the first constraint criterion includes at least one position degree of freedom and at least one direction degree of freedom. (Appendix 40) The first constraint criterion and the second constraint criterion are each a surgical system according to any one of Appendices 37 to 39, including at least one degree of freedom in a direction. (Appendix 41) The first constraint criterion is a surgical system according to any one of Appendices 37 to 40, including at least one more degree of freedom in position than the second constraint criterion. (Appendix 42) The first constraint criterion and the second constraint criterion are a surgical system according to any one of Appendices 37 to 41, including at least one common degree of freedom. (Appendix 43) The first constraint criterion includes a first elasticity parameter, and the second constraint criterion includes a second elasticity parameter different from the first elasticity parameter. The controller operates the manipulator. In the first mode, based on the first elasticity parameter, the controller maintains the alignment of the tool with respect to the trajectory. In the second mode, the surgical system according to Appendix 36 is further configured to maintain the alignment of the tool with respect to the trajectory based on the second elasticity parameter. (Appendix 44) The controller enables the tool to move more elastically with respect to the trajectory in the second mode than in the first mode, for the surgical system according to Appendix 43. (Appendix 45) The first elasticity parameter and the second elasticity parameter are each related to the elastic movement of the tool with respect to the trajectory in the common degree of freedom, for the surgical system according to any one of Appendices 43 or 44. (Appendix 46) The controller further operates the manipulator in the first mode so that as the measured value indicating the force acquired by the at least one sensor increases towards the predetermined condition, it is configured to resist the movement of the tool with respect to the trajectory with an increase in elasticity, for the surgical system according to Appendix 36. (Appendix 47) The tool defines a tool center point. The controller operates the manipulator in the first mode and is configured to limit the movement of the tool center point away from the trajectory according to the first constraint criterion, for the surgical system according to Appendix 36. (Appendix 48) The surgical system according to supplementary note 47, wherein the controller is configured to operate the manipulator in the second mode so as to allow movement of the tool center point away from the trajectory according to the second constraint criterion. (Supplementary note 49) The surgical system further includes a mode indicator coupled to the controller, wherein the controller is configured to activate the mode indicator in response to determining that the measured value indicating the force acquired by the at least one sensor satisfies a predetermined condition for communicating to the user a change of the operation of the manipulator from the first mode to the second mode, according to supplementary note 36. (Supplementary note 50) The surgical system according to supplementary note 36, wherein the controller is configured to operate the manipulator in the first mode so as to allow movement of the tool relative to the trajectory in at least one degree of freedom according to the first constraint criterion. (Supplementary note 51) The surgical system according to supplementary note 50, wherein the controller is configured to operate the manipulator in the second mode so as to allow movement of the tool relative to the trajectory in at least one degree of freedom according to the second constraint criterion. (Supplementary note 52) The controller is further configured to operate the manipulator in a third mode of maintaining alignment of the tool with respect to the trajectory according to a third constraint criterion different from both the first constraint criterion and the second constraint criterion, wherein the predetermined condition is further defined as a first predetermined condition, The surgical system according to supplementary note 36, wherein the controller is further configured to change the operation of the manipulator from the second mode to the third mode in response to determining that the measured value indicating the force acquired by the at least one sensor satisfies a second predetermined condition different from the first predetermined condition. (Supplementary note 53) The first predetermined condition is defined by a first force detected by a measured value acquired by the at least one sensor, the second predetermined condition is defined by a second force detected by a measured value acquired from the at least one sensor, and the second force is greater than the first force, according to supplementary note 52. (Supplementary note 54) The first constraint criterion includes a first number of degrees of freedom by which the movement of the tool is restricted with respect to the trajectory, the second constraint criterion includes a second number of degrees of freedom by which the movement of the tool is restricted with respect to the trajectory, the third constraint criterion includes a third number of degrees of freedom by which the movement of the tool is restricted with respect to the trajectory, and the third number of degrees of freedom is different from one or more of the first number of degrees of freedom and the second number of degrees of freedom. The controller is further configured to operate the manipulator to in the first mode, maintain alignment of the tool with respect to the trajectory based on the first number of degrees of freedom, in the second mode, maintain alignment of the tool with respect to the trajectory based on the second number of degrees of freedom, in the third mode, maintain alignment of the tool with respect to the trajectory based on the third number of degrees of freedom The surgical system according to any one of appended claims 52 or 53, which is configured as described above. (Appended claim 55) The first constraint criterion further includes a first elasticity parameter, the second constraint criterion further includes a second elasticity parameter, and the third constraint criterion further includes a third elasticity parameter different from one or more of the first elasticity parameter and the second elasticity parameter. The controller is further configured to operate the manipulator to in the first mode, maintain alignment of the tool with respect to the trajectory based on the first number of degrees of freedom and also based on the first elasticity parameter, in the second mode, maintain alignment of the tool with respect to the trajectory based on the second number of degrees of freedom and also based on the second elasticity parameter, in the third mode, maintain alignment of the tool with respect to the trajectory based on the third number of degrees of freedom and also based on the third elasticity parameter The surgical system according to appended claim 54, which is configured as described above. (Appended claim 56) The third number of degrees of freedom is less than the first number of degrees of freedom, and the controller enables movement of the tool with respect to the trajectory with at least one more degree of freedom in the third mode than in the first mode. The surgical system according to appended claim 55. (Appended claim 57) The degree of freedom of the third number is less than that of the second number, and the controller enables the movement of the tool relative to the trajectory with at least one more degree of freedom than the second mode in the third mode, the surgical system according to appended note 56. (Appended note 58) The first constraint criterion and the second constraint criterion each include at least one position degree of freedom and at least one direction degree of freedom, the surgical system according to appended note 55. (Appended note 59) The first constraint criterion, the second constraint criterion, and the third constraint criterion each include at least one direction degree of freedom, the surgical system according to appended note 55. (Appended note 60) The first constraint criterion includes at least one more position degree of freedom than the third constraint criterion, the surgical system according to appended note 55. (Appended note 61) The second constraint criterion includes at least one more position degree of freedom than the third constraint criterion, the surgical system according to appended note 60. (Appended note 62) The controller enables the movement of the more elastic tool relative to the trajectory in the second mode than in the first mode, the surgical system according to appended note 55. (Appended note 63) The controller enables the movement of the more elastic tool relative to the trajectory in the second mode than in the third mode, the surgical system according to appended note 62. (Appended note 64) The first constraint criterion includes a first elasticity parameter, the second constraint criterion includes a second elasticity parameter, and the third constraint criterion includes a third elasticity parameter different from one or more of the first elasticity parameter and the second elasticity parameter. The controller further operates the manipulator. In the first mode, based on the first elasticity parameter, maintain the alignment of the tool relative to the trajectory. In the second mode, based on the second elasticity parameter, maintain the alignment of the tool relative to the trajectory. In the third mode, it is configured to maintain the alignment of the tool relative to the trajectory based on the third elasticity parameter, the surgical system according to appended note 52. (Appended note 65) A patient tracker adapted for attachment to the target site, A navigation system configured to track the state of the patient tracker And further includes. The surgical system according to appended item 36, wherein the controller is coupled to the navigation system and is further configured to define the trajectory based on the tracking state of the patient tracker received from the navigation system. (Appended item 66) The tool includes a guide having a channel formed to receive an impactor assembly and to allow limited movement of the impactor assembly relative to the guide, and the impactor assembly has an interface for releasably securing a prosthesis. The surgical system according to appended item 36, wherein the manipulator is configured to support the guide with respect to the target site. (Appended item 67) The manipulator is configured to support the guide with respect to the target site while the impactor assembly is received in the channel of the guide and the prosthesis is secured to the impactor assembly. The target site is further defined as an acetabular cup. The at least one sensor is configured to obtain a measurement indicating the force resulting from the force applied to the impactor assembly to place the prosthesis in the acetabular cup. The controller is further configured to estimate the torque applied to the acetabular cup based on the detected force. The surgical system according to appended item 66, wherein the controller is further configured to change the operation of the manipulator from the first mode to the second mode in response to determining that the estimated torque applied to the acetabular cup satisfies the predetermined condition. (Appended item 68) The at least one sensor is further defined as one or more of a force torque transducer, a joint actuator current sensor, a joint force sensor, a joint torque sensor, and a joint encoder, according to any one of appended items 36, 46, 49, 52, 53, and 67. (Appended item 69) A tool for engaging a target site; A manipulator configured to support the tool with respect to the target site; A patient tracker adapted for attachment to the target site; A navigation system configured to track the state of the patient tracker; A controller coupled to the manipulator and the navigation system, a first mode for maintaining alignment of the tool with respect to the target site according to a first constraint criterion, a second mode for maintaining alignment of the tool with respect to the target site according to a second constraint criterion different from the first constraint criterion, and a controller configured to operate the manipulator between the two, comprising, the controller is further configured to compare the tracked movement of the tool with the movement of the patient tracker based on the tracking state received from the navigation system, the controller is further configured to change the operation of the manipulator from the first mode to the second mode in response to determining that the tracked movement of the tool corresponds to the movement of the patient tracker, a surgical system. (Appendix 70) A method of operating a surgical system including an impactor assembly having an interface for releasably fixing a prosthesis, a guide having a channel formed to receive the impactor assembly, a manipulator configured to support the guide with respect to a target site along a track, at least one sensor, and a controller coupled to the manipulator and the at least one sensor, comprising: the controller, operating the manipulator in a first mode for maintaining alignment of the guide with respect to the track according to a first constraint criterion; operating the manipulator in a second mode for maintaining alignment of the guide with respect to the track according to a second constraint criterion different from the first constraint criterion; detecting a force generated between the target site and the manipulator based on measurements from the at least one sensor; determining that the force meets a predetermined condition and, in response, changing the operation of the manipulator from the first mode to the second mode is configured to perform. A method. (Appendix 71) a tool for engaging a target site, a manipulator configured to support the tool, A sensing system configured to detect one or more system conditions related to one or more of the tool, the manipulator, the target site, or combinations thereof; coupled to the manipulator and the sensing system, operate the manipulator to maintain alignment of the tool with respect to the target site according to a first constraint criterion, and in response to detection of the one or more system conditions, operate the manipulator to maintain alignment of the tool with respect to the target site according to a second constraint criterion different from the first constraint criterion A controller configured as follows; A surgical system comprising: (Appendix 72) The surgical system according to Appendix 71, wherein the controller is configured to determine parameters of the second constraint criterion based on system conditions detected from the sensing system. (Appendix 73) A tool for engaging a target site along a trajectory; A manipulator configured to support the tool; At least one sensor configured to obtain a measurement indicating a force generated between the target site and the manipulator; A controller coupled to the manipulator and the at least one sensor, operate the manipulator to maintain alignment of the tool with respect to the trajectory according to a first constraint criterion, evaluate the obtained measurement indicating the force, and in response to the evaluation, operate the manipulator to maintain alignment of the tool with respect to the trajectory according to a second constraint criterion different from the first constraint criterion A controller configured as follows; A surgical system comprising: (Appendix 74) The surgical system according to Appendix 73, wherein the controller is configured to determine parameters of the second constraint criterion based on the obtained measurement indicating the force. (Appendix 75) A tool for engaging a target site; A manipulator configured to support the tool with respect to the target site; A patient tracker adapted for attachment to the target site; A navigation system configured to track the state of the patient tracker; A controller coupled to the manipulator and the navigation system, operate the manipulator to maintain alignment of the tool with respect to the target site according to a first constraint criterion, Based on the tracking state of the patient tracker received from the navigation system, evaluate the tracked movement of the tool with respect to the movement of the patient tracker. According to the evaluation, operate the manipulator to maintain the alignment of the tool with respect to the target site according to a second constraint criterion different from the first constraint criterion. A controller configured to comprise a surgical system. (Appendix 76) The surgical system according to Appendix 75, wherein the controller is configured to determine parameters of the second constraint criterion based on the evaluated tracked movement. (Appendix 77) A tool for engaging a target site, A manipulator configured to support the tool with respect to the target site, A patient tracker adapted for attachment to the target site, A navigation system configured to track the state of the patient tracker, A controller coupled to the manipulator and the navigation system, Operate the manipulator to restrict the movement of the tool with respect to a virtual boundary associated with the target site according to a first constraint criterion, Based on the tracking state of the patient tracker received from the navigation system, evaluate the tracked movement of the tool with respect to the movement of the patient tracker. According to the comparison, operate the manipulator to limit the movement of the tool with respect to the virtual boundary according to a second constraint criterion different from the first constraint criterion. A controller configured to comprise a surgical system.

Claims

1. A tool for engaging a target site along an orbit, a manipulator configured to support the tool, a sensing system configured to detect one or more system conditions related to one or more of the tool, the manipulator, the target site, or combinations thereof, a controller coupled to the manipulator and the sensing system, a first mode for maintaining alignment of the tool with respect to the orbit according to a first constraint criterion, a second mode for maintaining alignment of the tool with respect to the orbit according to a second constraint criterion different from the first constraint criterion, and a controller configured to operate the manipulator between the first mode and the second mode, and including, the controller is further configured to change the operation of the manipulator from the first mode to the second mode in response to determining that at least one of the one or more system conditions meets a predetermined condition, a surgical system.

2. The first constraint criterion includes a first number of degrees of freedom by which the movement of the tool is restricted with respect to the orbit, the second constraint criterion includes a second number of degrees of freedom by which the movement of the tool is restricted with respect to the orbit, the second number of degrees of freedom is different from the first number of degrees of freedom, the controller is further configured to operate the manipulator, in the first mode, maintain alignment of the tool with respect to the orbit based on the first number of degrees of freedom, in the second mode, maintain alignment of the tool with respect to the orbit based on the second number of degrees of freedom, The surgical system according to claim 1, wherein the surgical system is configured to perform the operation.

3. The second number of degrees of freedom is less than the first number of degrees of freedom, and the controller enables movement of the tool with respect to the orbit with at least one more degree of freedom in the second mode than in the first mode. The surgical system according to claim 2.

4. Whether the first constraint criterion includes at least one position degree of freedom and at least one direction degree of freedom, Whether the first constraint criterion and the second constraint criterion each include at least one direction degree of freedom, Whether the first constraint criterion includes at least one more position degree of freedom than the second constraint criterion, or, The surgical system according to claim 2 or 3, wherein the first constraint criterion and the second constraint criterion include at least one common degree of freedom.

5. The first constraint criterion includes a first elasticity parameter, and the second constraint criterion includes a second elasticity parameter different from the first elasticity parameter. The controller is further configured to operate the manipulator to in the first mode, maintain the alignment of the tool with respect to the trajectory based on the first elasticity parameter; in the second mode, maintain the alignment of the tool with respect to the trajectory based on the second elasticity parameter. The surgical system according to any one of claims 1 to 4.

6. The controller enables a more elastic movement of the tool with respect to the trajectory in the second mode than in the first mode. The first elasticity parameter and the second elasticity parameter are each related to an elastic movement of the tool with respect to the trajectory in a common degree of freedom. The surgical system according to claim 5.

7. The tool defines a tool center point. The controller is configured to operate the manipulator in the first mode to restrict movement of the tool center point away from the trajectory according to the first constraint criterion. The controller is configured to operate the manipulator in the second mode to enable movement of the tool center point away from the trajectory according to the second constraint criterion. The surgical system according to any one of claims 1 to 6.

8. Further comprising a mode indicator coupled to the controller. The controller is configured to activate the mode indicator in response to determining that at least one of the one or more system conditions satisfies the predetermined condition, and to notify the user of a change in the operation of the manipulator from the first mode to the second mode. The surgical system according to any one of claims 1 to 7.

9. The controller is configured to operate the manipulator in the first mode to enable movement of the tool with respect to the trajectory in at least one degree of freedom according to the first constraint criterion. The controller is configured to operate the manipulator in the second mode so as to enable movement of the tool relative to the trajectory in at least one degree of freedom according to the second constraint criterion, for the surgical system according to any one of claims 1 to 8.

10. The controller is further configured to operate the manipulator in a third mode to maintain alignment of the tool with respect to the trajectory according to a third constraint criterion different from both the first constraint criterion and the second constraint criterion. The predetermined condition is further defined as a first predetermined condition. The controller is further configured to change the operation of the manipulator from the second mode to the third mode in response to determining that at least one of the one or more system conditions satisfies a second predetermined condition different from the first predetermined condition, for the surgical system according to any one of claims 1 to 9.

11. The first constraint criterion includes a first number of degrees of freedom by which the movement of the tool is restricted with respect to the trajectory, the second constraint criterion includes a second number of degrees of freedom by which the movement of the tool is restricted with respect to the trajectory, the third constraint criterion includes a third number of degrees of freedom by which the movement of the tool is restricted with respect to the trajectory, and the third number of degrees of freedom is different from one or more of the first number of degrees of freedom and the second number of degrees of freedom. The controller is further configured to operate the manipulator to in the first mode, maintain alignment of the tool with respect to the trajectory based on the first number of degrees of freedom. in the second mode, maintain alignment of the tool with respect to the trajectory based on the second number of degrees of freedom. in the third mode, maintain alignment of the tool with respect to the trajectory based on the third number of degrees of freedom, for the surgical system according to claim 10.

12. The first constraint criterion further includes a first elasticity parameter, the second constraint criterion further includes a second elasticity parameter, the third constraint criterion further includes a third elasticity parameter different from one or more of the first elasticity parameter and the second elasticity parameter. The controller is further configured to operate the manipulator to In the first mode, based on the first number of degrees of freedom and also based on the first elastic parameter, the alignment of the tool with respect to the trajectory is maintained. In the second mode, based on the second number of degrees of freedom and also based on the second elastic parameter, the alignment of the tool with respect to the trajectory is maintained. The surgical system according to claim 11, wherein in the third mode, based on the third number of degrees of freedom and also based on the third elastic parameter, the alignment of the tool with respect to the trajectory is maintained.

13. The third number of degrees of freedom is less than the first number of degrees of freedom, and the controller enables movement of the tool with respect to the trajectory with at least one more degree of freedom in the third mode than in the first mode, or The third number of degrees of freedom is less than the second number of degrees of freedom, and the controller enables movement of the tool with respect to the trajectory with at least one more degree of freedom in the third mode than in the second mode, the surgical system according to claim 12.

14. Whether each of the first constraint criterion and the second constraint criterion includes at least one position degree of freedom and at least one direction degree of freedom, Whether each of the first constraint criterion, the second constraint criterion, and the third constraint criterion includes at least one direction degree of freedom, Whether the first constraint criterion includes at least one more position degree of freedom than the third constraint criterion, or The surgical system according to claim 12 or 13, wherein the second constraint criterion includes at least one more position degree of freedom than the third constraint criterion.

15. The controller enables more elastic movement of the tool with respect to the trajectory in the second mode than in the first mode, or The surgical system according to any one of claims 12 to 14, wherein the controller enables more elastic movement of the tool with respect to the trajectory in the second mode than in the third mode.

16. The first constraint criterion includes a first elastic parameter, the second constraint criterion includes a second elastic parameter, and the third constraint criterion includes a third elastic parameter that is different from one or more of the first elastic parameter and the second elastic parameter, The controller further operates the manipulator In the first mode, based on the first elasticity parameter, the alignment of the tool with respect to the trajectory is maintained, In the second mode, based on the second elasticity parameter, the alignment of the tool with respect to the trajectory is maintained, The surgical system according to any one of claims 10 to 15, wherein in the third mode, it is configured to maintain the alignment of the tool with respect to the trajectory based on the third elasticity parameter.

17. The sensing system includes at least one sensor configured to obtain a measurement value indicating a force generated between the target site and the manipulator, The measurement value indicating the force obtained by the at least one sensor defines at least one of the one or more system conditions, and the controller controls the operation of the manipulator, In response to determining that the force detected by the at least one sensor satisfies the first predetermined condition, from the first mode to the second mode, and The surgical system according to any one of claims 10 to 16, wherein in response to determining that the force detected by the at least one sensor satisfies the second predetermined condition, it is configured to change from the second mode to the third mode.

18. The first predetermined condition is defined by a first force detected by the at least one sensor, the second predetermined condition is defined by a second force detected by the at least one sensor, and the second force is greater than the first force. The surgical system according to claim 17.

19. Further includes a patient tracker adapted for attachment to the target site, The sensing system includes a navigation system configured to track the state of the patient tracker, The tracking state of the patient tracker defines at least one of the one or more system conditions, and in response to a determination that the tracking state of the patient tracker satisfies the predetermined condition, the controller changes the operation of the manipulator from the first mode to the second mode. The surgical system according to any one of claims 1 to 18.

20. The controller is further configured to compare the tracked movement of the tool with the movement of the patient tracker based on the tracking state received from the navigation system, the tracked movement of the tool defines at least one of the one or more system conditions, The surgical system according to claim 19, wherein the predetermined condition is defined based on the tracked movement of the tool corresponding to the tracked state of the patient tracker.

21. The sensing system includes at least one sensor configured to obtain a measurement indicative of a force generated between the target site and the manipulator, The measurement indicative of the force obtained by the at least one sensor defines at least one of the one or more system conditions, and the controller is configured to change the operation of the manipulator from the first mode to the second mode in response to determining that the force detected by the at least one sensor satisfies the predetermined condition. The surgical system according to any one of claims 1 to 20.

22. The controller is further configured to operate the manipulator in the first mode to resist the movement of the tool relative to the trajectory with an increase in elasticity as the measurement indicative of the force obtained by the at least one sensor increases towards the predetermined condition. The surgical system according to claim 21.

23. The tool includes the guide having a channel formed to receive an impactor assembly and allow limited movement of the impactor assembly relative to the guide, the impactor assembly having an interface for releasably securing a prosthesis, The manipulator is configured to support the guide along the trajectory relative to the target site while the impactor assembly is received in the channel of the guide and the prosthesis is secured to the impactor assembly, The target site is further defined as an acetabular cup, The at least one sensor is configured to detect the force resulting from the force applied to the impactor assembly to install the prosthesis in the acetabular cup. The controller is further configured to estimate a torque applied to the acetabular cup based on the detected force. The controller is further configured to change an operation of the manipulator from the first mode to the second mode in response to determining that the estimated torque applied to the acetabular cup satisfies the predetermined condition, the surgical system according to claim 21 or 22.

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