Surgical robot system

Abstract

The present invention relates to a surgical robot system, which includes a robotic arm (1) holding an end effector (11) and a control unit (13), the control unit being configured to controllably move the robotic arm and maintain the end effector (11) in at least one target position relative to a patient, wherein the control unit is configured to: (i) activate a manual guidance mode based on a first input continuously applied by a user to the robotic arm (1), wherein the robotic arm can be freely moved by the user; (ii) activate a computed trajectory mode based on a second input different from the first input continuously applied by the user to the robotic arm (1), wherein the robotic arm moves to the target position according to the computed trajectory; (iii) when the computed trajectory is activated, detect that the end effector (11) satisfies at least one predetermined safety condition and automatically switch to a servo control mode, wherein the robotic arm (1) can be automatically moved to maintain the end effector (11) in the target position relative to a tracker attached to the patient.

Description

Technical Field

[0001] The present invention relates to a surgical robot system, which includes a robotic arm holding an end effector and a control unit configured to controllably move the robotic arm and maintain the end effector in at least one target position relative to a patient. Background Art

[0002] Surgical robotic arms have been used to assist a user (e.g., a surgeon) during a surgical intervention.

[0003] For example, in spinal surgery, a user may have to implant one or several threaded elements into at least one vertebra. The robotic arm can assist the user by holding a drilling guide and maintaining the drilling guide along a planned axis. Thus, the user can use a hand-held drill to drill a hole for receiving the threaded element in the vertebra along the planned axis through the drilling guide held by the robotic arm.

[0004] However, when using such a robotic arm, several challenges will be encountered.

[0005] The first challenge relates to safety, i.e., ensuring that the robotic arm does not cause any harm to the patient and medical staff.

[0006] The second challenge is to define an appropriate cooperation between the user and the robotic arm. "Cooperation" means that the robotic arm does not replace the human user, but assists him / her by complementing his / her capabilities and allowing him / her to focus on a specific task.

[0007] There are known robotic arms that move towards a target position as long as the user applies continuous pressure to a button or a pedal. However, such displacement is slow and thus has the effect of significantly increasing the operation time. In addition, the robotic arm trajectory may not take into account all obstacles present near the patient. For safety reasons, once the user releases the button or the pedal, the robotic arm stops.

[0008] On the other hand, since the patient may move during a surgical intervention, e.g., due to breathing or a mechanical reaction to treating the patient with surgical tools, it is desirable for the robotic arm to be able to maintain the end effector in a target position relative to the patient.

[0009] Document US 2011 / 0190790 teaches a robotic system that includes a robotic arm holding an end effector and a control unit. Virtual walls define a safe working area for the robotic arm. The control unit is configured to stop the robotic arm or provide haptic feedback when the robotic arm leaves the working area.

[0010] Document US 2014 / 0350571 teaches a robotic system, which includes a first robotic arm holding an end effector, a second robotic arm holding a sensor in contact with a patient's body, and a control unit configured to adjust the position of the first robotic arm based on the displacement of the patient's body detected by the second robotic arm. SUMMARY OF THE INVENTION

[0011] The object of the present invention is to design a surgical robotic system that allows for improved collaboration between the user and the robotic arm while ensuring safety.

[0012] To this end, the present invention provides a surgical robotic system, which includes a robotic arm holding an end effector and a control unit configured to controllably move the robotic arm and maintain the end effector in at least one target position relative to a patient, wherein the control unit is configured to:

[0013] (i) Activate a manual guidance mode based on a first input continuously applied by the user to the robotic arm, wherein the robotic arm can be freely moved by the user;

[0014] (ii) Activate a computed trajectory mode based on a second input different from the first input continuously applied by the user to the robotic arm, wherein the robotic arm moves to the target position according to the computed trajectory;

[0015] (iii) Detect when the computed trajectory mode is activated: that the end effector satisfies at least one predetermined safety condition, and automatically switch to a servo control mode, wherein the robotic arm can be automatically moved to maintain the end effector in the target position relative to a tracker attached to the patient.

[0016] The robotic system thus combines at least three usage modes: a manual guidance mode, a computed trajectory mode, and a servo control mode. The combination of the modes allows for optimizing the collaboration between the robotic arm and the user. In the manual guidance mode, the user is allowed to freely and quickly move the robotic arm to bring the end effector to a rough position close to the target position; in the computed trajectory mode, the robotic arm moves the end effector to the precise target position, and at the same time, due to the second input, the robotic arm is still controlled by the user; in the servo control mode, if the safety condition is met, the robotic arm can be automatically moved to maintain the end effector in the target position. Thus, during the entire operation of the robotic arm, the user and / or the control unit ensure safety.

[0017] In some embodiments, a predetermined safety condition is that a tracker attached to a patient remains within a controlled volume relative to the base of the robotic arm, the dimensions of the controlled volume being larger in the expected movement direction of the tracker than in the non-expected movement direction of the tracker.

[0018] In some embodiments, the target position is selected based on the following parameters:

[0019] - The drilling axis;

[0020] - The drilling axis and the drilling depth;

[0021] - The cutting plane;

[0022] - The optimal working position of the active surgical tool.

[0023] In some embodiments, the control unit is configured to adjust the calculated trajectory based on the orientation applied by the user in the manual guidance mode of the robotic arm.

[0024] In some embodiments, the system includes a user interface coupled to the control unit and configured to provide information about the current mode.

[0025] The user interface may include a display monitor that is arranged on the robotic arm and configured to display changing graphical items according to the current mode.

[0026] The user interface may include a ring that includes a plurality of LEDs configured to have a predetermined color and / or blinking state according to the current mode.

[0027] In some embodiments, the control unit is further configured to activate a safety mode that prohibits movement of the robotic arm based on detecting movement of the robotic arm beyond a predetermined amplitude, direction, acceleration, and / or speed in the servo control mode.

[0028] In some embodiments, the control unit is configured to continuously maintain the end effector at a plurality of target positions.

[0029] In some embodiments, the robotic arm includes a first switch configured for a first input to be applied by the user and a second switch different from the first switch configured for a second input to be applied by the user.

[0030] The control unit may be configured to be able to switch between two consecutive targets when the user double-clicks the second switch at any time during the surgery.

[0031] In some embodiments, the control unit is configured to place the robotic arm in an idle mode when the tracking of the robotic arm is not enabled and the surgical robotic system is in a manual guidance mode or a computed trajectory mode.

[0032] In some embodiments, the control unit is configured to place the robotic arm in a specific waiting mode when the tracking of the robotic arm is lost while the surgical robotic system is in a servo control mode, wherein when the tracking is restored, the specific waiting mode can be switched back to the servo control mode.

[0033] Another object is a method for positioning an end effector held by a robotic arm relative to a patient, comprising:

[0034] (i) Activating a manual guidance mode based on a first input continuously applied by a user to the robotic arm, wherein the robotic arm can be freely moved by the user;

[0035] (ii) Activating a computed trajectory mode based on a second input different from the first input continuously applied by the user to the robotic arm, wherein the robotic arm moves to a target position according to the computed trajectory;

[0036] (iii) Detecting when the computed trajectory is activated: the end effector is within a controlled volume around the target position and automatically switching to a servo control mode, wherein the robotic arm can automatically move within the controlled volume to maintain the end effector at the target position relative to the patient.

[0037] In some applications, the target position is planned relative to the spine of the patient.

[0038] In some applications, the target position is planned relative to the bones of the patient. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Based on the drawings, further features and advantages of the present invention will become apparent from the following detailed description, wherein:

[0040] Figure 1 Shows an overall overview of the robotic system;

[0041] Figure 2 Is a perspective view of an embodiment of the robotic arm;

[0042] Figure 3 Is Figure 2 A perspective view of the end effector of the robotic arm of;

[0043] Figure 4 Is a state machine showing the operation of the robotic system in its different modes. DETAILED DESCRIPTION

[0044] The present invention can be implemented in the context of surgical intervention on a patient's bone, including but not limited to: implanting orthopedic implants in the spine, such as pedicle screws, implanting various orthopedic implants in the bone, reducing and fixing fractures during orthopedic surgery, or simply positioning a guide or cannula at a desired position relative to a predetermined target.

[0045] More specifically, the present invention can be used to maintain the target of pedicle screw placement defined in a preoperative or intraoperative image-based planning step.

[0046] In this regard, the robotic system can be coupled to other surgical systems: imaging devices, such as a motorized C-arm imaging unit (as described in EP2868277) or a CT scan unit, such as Mobius Airo.

[0047] When coupled to a positioning system, these systems provide 2D and 3D imaging capabilities and navigation capabilities, as described in EP3361977.

[0048] In view of performing the navigation, the end effector and / or the tool(s) used during the surgical intervention are equipped with trackers, such as optical, electromagnetic, ultrasonic, or inertial trackers, and are measured by at least one positioning system. Another tracker is mounted on the patient's bone to be operated on (or on another bone that can be assumed to be fixed to the bone being operated on), and is also detected by the positioning system. This other tracker is designated as a reference tracker attached to the patient.

[0049] The robotic system includes:

[0050] - A robotic arm having a proximal end extending from a base, which can be a movable cart or an imaging device, or can be attached to the operating table,

[0051] - An end effector attached to the distal end of the robotic arm, and

[0052] - A control unit configured to controllably move the robotic arm and maintain the end effector in at least one target position relative to the patient.

[0053] The robotic arm includes multiple degrees of freedom of translation and / or rotation. Generally, the robotic arm includes six or seven motorized degrees of freedom. For this purpose, the robotic arm includes multiple articulated segments driven by motors. The robotic arm can be, for example, the LBR Med provided by KUKA. TM Robot.

[0054] The end effector includes a handgrip portion that is configured to be held by a user's hand for manipulating the robotic arm, particularly in the manual guidance mode described below.

[0055] In some embodiments, the handgrip portion includes a first switch and a second switch that are configured to be actuated individually by the user to trigger an operating mode of the robotic arm. The switches can include buttons, resistive switches, piezoelectric switches, etc. Although the switches can be arranged in another part of the robotic arm, they are preferably arranged on the handgrip portion such that the user can actuate one of the switches with a single hand while manipulating the end effector to move the robotic arm (in the manual guidance mode) or to follow the movement of the robotic arm (in the computed trajectory mode).

[0056] In some embodiments, the handgrip portion includes at least one user interface that is configured to provide information about the current mode. Although the user interface can be arranged in another part of the robotic system, it is advantageously located on or near the handgrip portion to allow the user to focus on the end effector when operating the robotic arm. According to an embodiment, the user interface includes a display having graphical items (e.g., text, markers with variable colors, etc.) that change according to the current mode. According to another embodiment, the user interface can include a plurality of LEDs. The LEDs can be configured to have a predetermined color and / or blinking state according to the current mode. The LED ring can be arranged to surround the handgrip portion or a ring of the robotic arm near the handgrip portion.

[0057] The end effector further includes a passive or active tool holder. The passive tool holder is configured to hold a guide in which a surgical tool slides, and the surgical tool can be a drilling guide, a drill, a cutting guide, or any active tool. The active tool holder is configured to hold an active surgical tool, which can be a drill, an ultrasonic cutter, a burr, or any active tool. The active tool holder can also hold an actuator including several degrees of freedom of movement, which then moves and activates the active surgical tool. In a preferred embodiment, the tool holder holds a linear actuator that can translate a drill or a burr along its axis. The tool holder further includes a tracker that can be detected by a positioning system.

[0058] The handgrip portion and / or the tool holder can be reused and sterilized, or can be used as disposable components.

[0059] The control unit includes a processor, a data storage device, and a communication device. The control unit can be advantageously embedded in the base of the robotic arm. The base of the robotic arm also includes switches, such as a power switch, an emergency button, and the like.

[0060] The robotic system can operate as follows.

[0061] Intraoperative 3D and / or 2D images are obtained using an imaging system, such as a C-arm.

[0062] The surgeon can complete the planning on these images by defining at least one surgical target to be processed by the robotic system. These targets are defined in the coordinate system of the imaging system.

[0063] The robotic system can move on the wheels of the cart forming the base of the robotic arm and be brought near the surgical table.

[0064] The patient is equipped with at least one reference tracker that can be detected by the positioning system. Another tracker is also attached to the end effector, particularly to the tool holder. Based on the positioning data of the two trackers, the control unit can determine the relative position of the end effector with respect to the patient. Various registration methods can be used to determine the transformation between the coordinate system of the patient reference tracker and the coordinate system of the imaging system. Thus, the targets are known in the coordinate system attached to the patient reference tracker. Since the robot is equipped with a tracker, the transformation between the current end effector position and the target position can be calculated, and the robot can be assigned to a position aligned with the target.

[0065] As an alternative to image-based planning, the targets can also be directly defined in the coordinate system of the reference tracker attached to the patient. For example, a navigation pointer can be used to define the target, which is then removed, and the axis of the robotic end effector is aligned with the target position.

[0066] Start the robotic system startup program, including safety tests.

[0067] After being ready, the robotic arm is in the idle mode. In this idle mode, the robotic arm cannot move autonomously.

[0068] Then, the user can activate the first switch in a continuous manner to enable the manual guidance mode, in which the user can freely move the robotic arm by manipulating the hand grip. This mode can use robotic devices, such as the KUKA LBR iiwa TMIt is implemented in the traditional cooperation mode of the robotic arm. Therefore, the user can easily move the end effector close to the first surgical target defined in the plan. Since the robotic arm is continuously manipulated and controlled by the user, its displacement can be relatively fast while allowing obstacles to be avoided. As long as the activation of the first switch is maintained, the manual guidance mode is maintained. Once the user stops activating the first switch, the control unit stops the motor so that the user can no longer move the robotic arm and the robotic arm cannot move autonomously (idle mode). In a preferred embodiment, the first switch is located on the end effector but closer to the robotic base proximally.

[0069] Once the tracker on the tool holder of the end effector mounted on the robotic arm enters the measurement area of the positioning system and is precisely positioned by the positioning system, the operator can stop the manual guidance mode and enable the calculated trajectory mode by continuously activating the second switch instead of the first switch. The possible transition between the manual guidance mode and the calculated trajectory mode can be visualized via the user interface, for example, by changing the LED color and / or blinking state when the tracker becomes detectable by the positioning system. In a preferred embodiment, the second switch is located on the end effector but closer to the end opposite the base distally.

[0070] In this calculated trajectory mode, the user only accompanies the robotic arm, which automatically moves according to the pre-calculated trajectory to the surgical target. The obligation of the user to continuously activate the second switch ensures safety. Once the user stops activating the second switch, the control unit stops the motor so that the robotic arm can no longer move. Therefore, the calculated trajectory mode can be considered a cooperation mode of the robotic system. When the robot reaches the target position, the user interface will indicate a signal. In a preferred embodiment, the LED turns green, which means the user is permitted to perform the surgery and insert the instrument through the tool holder.

[0071] If the positioning unit can no longer detect the end effector tracker, for example, in the case of optical positioning, because the tracker is hidden by another object in the field of view of the optical positioning system, the control unit exits the current mode and stops the robotic arm. This situation can be indicated by the user interface, for example, by a specific LED color and / or blinking state. In a preferred embodiment, if the current mode is the manual guidance mode or the calculated trajectory mode, the LED becomes blinking white, or if the current mode is the servo control mode, it becomes blinking orange.

[0072] Once the target has been reached and the user interface gives a green light, in the case where the user applies excessive force on the robot end effector and the end effector tracker is no longer aligned with the target within a given range, the control unit first tries to bring the robot back to its target, and the user interface displays, for example, an orange light. However, if the robot is not successful, the control unit exits the servo control mode and stops the robotic arm. This situation can be indicated by the user interface, for example, by a specific LED color and / or blinking state. In a preferred embodiment, the LED turns orange.

[0073] In a preferred embodiment, the user can impose a specific orientation on the tool holder during the manual guidance mode, and then the global orientation of the tool holder is retained in its basic components to reach the target. This orientation can particularly determine pre-positioning the robotic arm in a position favorable for the surgical treatment to avoid, for example, collisions with other surgical instruments. If the user sees that a collision may occur when the user presses the second switch, the user can stop, return to the manual guidance mode using the first switch, and change the orientation of the tool holder in this mode, and then move forward to the target by pressing the second switch. In this mode, the final target calculation is performed so that the robotic arm is oriented as close as possible to the initial robotic arm position. This mode benefits from the redundancy of a six-axis or seven-axis robot to align the linear trajectory to the final target position (which only requires five degrees of freedom). Among the infinite set of orientations available for the robot around the tool holder axis, the orientation closest to the initial robot position is selected.

[0074] In the next chapter, the description focuses on the case of a passive tool holder in which various surgical tools (drills, screwdrivers, etc.) slide.

[0075] Once the robotic arm has reached the planned surgical target, the user can release the second switch. This situation can be detected based on the comparison between the position of the tracker of the end effector and the desired target position. Since neither the first switch nor the second switch is activated, the control unit triggers an automatic mode, servo-controlling the small movements of the patient (such as breathing) by monitoring the relative position of the end effector and the patient allowed by the tracking system. The transition between the calculated trajectory mode and the servo control mode can be visualized via the user interface, for example, by different LED colors and / or different blinking states.

[0076] In this servo control mode, the user can rely on the assistance provided by the robotic system to perform the planned operation, and the robotic system itself holds the guide or the tool. Then, the user does not need to activate the switch and can focus on the tool for performing the intervention.

[0077] In the case of placing the pedicle screw, the surgeon can manipulate the drill. Drilling can be achieved by a manual drill bit slid into the tool holder or an analogue such as an ultrasonic tool.

[0078] In another embodiment, the drilling instrument can be an active end effector, such as a small and compact active robot for bone deburring.

[0079] For safety reasons, in servo control mode, the end effector moves and is servoed to the target only when certain safety conditions are met. Several safety conditions can be implemented to authorize the activation of the servo control mode, including one or more of the conditions in the following list:

[0080] (a) In a first embodiment, the safety condition is met if the end effector position remains within a restricted volume around the target position. For example, if the target moves more than five millimeters relative to its initial position in the coordinate system of the robot arm base, the safety condition is not met, the robot arm will stop, the user interface will display a signal, and the user will need to press one of the switches again to reactivate the robot arm in manual guidance mode or calculated trajectory mode. Advantageously, the volume is updated in real time based on the patient's movement, such as breathing or mechanical response to tool use on the patient.

[0081] (b) In another preferred embodiment with more advanced features, the safety condition is met if the detected movement of the reference bone tracker relative to the robot base corresponds to the expected movement of the bone within a given eight - millimeter range, but the safety condition is not met if the detected movement exceeds three millimeters in an unexpected movement direction. The expected movement can be the result of respiratory simulation or the result of the simulated interaction of the surgical tool with the bone applying pressure to the bone. In other words, the safety condition corresponds to the volume within which the bone tracker can move, the dimensions of which in a first direction are greater than those in a second direction, the first direction being the direction of the expected movement of the bone tracker and the second direction being the direction of the unexpected movement of the bone tracker.

[0082] (c) In another preferred embodiment, the safety condition is not met if the detected movement of the reference bone tracker relative to the robot base has a speed exceeding a given threshold.

[0083] (d) In another preferred embodiment, if the detected acceleration of the reference bone tracker relative to the base of the robotic arm exceeds a given threshold, the safety condition is not met. This may occur, for example, if during a surgical intervention, a tracker attached to the patient using magnetic fixation is inadvertently displaced. In fact, vibrations may cause the patient tracker to fall or shift, and since the robotic arm is servoed to the position of the patient tracker, the robotic arm may move rapidly and significantly to follow the fallen or shifted tracker, which may harm the patient and / or medical staff.

[0084] The various safety conditions can be used individually or in part together.

[0085] The above safety conditions do not replace the standard safety conditions of the surgical robot, and they are cumulative. For example, any deviation of the robotic arm from its calculated position target in the bone reference tracker exceeding a threshold of one millimeter triggers an alarm and stops the robot. Similarly, the standard safety conditions for measuring the consistency of the robotic position sensors, the robotic force sensors, or simply the redundant measurements of excessive force applied to the robot trigger an alarm and maintain an effective safety stop.

[0086] If the user activates the first switch or the second switch, the control unit can exit the safety mode.

[0087] As long as the operation steps of the target position are executed, the user can stop the servo control mode.

[0088] For example, if the user has drilled a hole in a vertebra according to the first target, the user may wish to move the robotic arm to the next target to drill a hole in another vertebra. In a preferred embodiment, if the user double-clicks and presses the second switch twice, at any time, the robotic arm will switch to the next planned target (if any).

[0089] In some cases, the user may wish to move the robotic arm away from the surgical site. For example, if the user has drilled a hole in a vertebra, he may wish to immediately insert a pedicle screw into the hole. To this end, the user can continuously activate the first switch to trigger the manual guidance mode and quickly move the robotic arm away from the surgical site to have enough space to perform the implantation of the pedicle screw. Then, the user can continuously activate the second switch to bring the robotic arm back to its target position and use robotic guidance in the servo control mode to perform more actions.

[0090] Thereafter, if a new screw is to be implanted, the user can select the next target by double-clicking (as described in the previous embodiments) and perform the same sequence as above, starting from the manual guidance mode and quickly moving the end effector near the next target.

[0091] In a preferred embodiment, the holding tool is active and holds, for example, a drill. Once the end effector has reached its target, the control unit moves the high-speed rotating drill along its axis in a linear motion along the planned trajectory. As long as the trajectory complies with the safety constraints, the safety conditions are met. This represents an extension of the above-described situation, where the position must comply with the safety constraints. For example, if the tool itself remains aligned with the target line calculated in the robot base coordinate system, the active tool trajectory complies with the safety conditions.

[0092] Figure 1 An embodiment of the surgical robot system as described above in the context of spinal surgery in the operating room is shown.

[0093] The operating room includes an operating table 14. For spinal surgery, the patient can lie prone on the operating table, but for other surgical interventions, the patient can be positioned in other positions. Although not shown, at least one tracker is rigidly attached to the patient, particularly to the vertebrae in the case of spinal surgery. Several reference trackers can be used, one reference tracker for each vertebra being operated on.

[0094] The operating table may also include an imaging system, such as a C-arm 15. The imaging system allows for the acquisition of intraoperative images of the patient.

[0095] The robot system includes a robot arm 1, which includes a base 10 and an end effector 11, which will be described in more detail with reference to Figure 2 and Figure 3 The base is fixed to a mobile cart, which remains stationary relative to the operating table during the surgical intervention.

[0096] The control unit for controlling the robot arm may be embedded in the cart and is denoted by the reference numeral 13.

[0097] Figure 2 An enlarged view of the robot arm is shown.

[0098] The robot arm 1 includes a plurality of articulated segments. The end segment opposite the base 10 includes the end effector 11.

[0099] The end effector 11 includes a hand grip portion configured to be held by the user's hand. For this purpose, the hand grip portion may have an ergonomic shape, such as a cylindrical shape, the diameter of which is adapted such that the hand grip portion can be at least partially surrounded by the user's hand.

[0100] The hand grip portion includes two switches 4, 5 that are different from each other. The first switch is configured to trigger the manual guidance mode, while the second switch is configured to trigger the calculated trajectory mode. To implement each of the said modes, the user must continuously activate the corresponding switch. If the user releases the first switch or the second switch before the robotic arm reaches the target, the robotic arm will immediately stop. The switches are advantageously arranged on the outer surface of the hand grip portion such that the user can manipulate the end effector and activate the switches with a single hand.

[0101] The end effector further includes an LED ring 3, which includes a plurality of LEDs configured to emit light with different colors and / or different blinking states. For example, the LEDs can emit the following light signals:

[0102] - Blinking white when the robotic arm is in the idle mode;

[0103] - Steady white when the robotic arm is in the manual guidance mode or the calculated trajectory mode and the tracker can be detected by the positioning system;

[0104] - Steady green when the robotic arm is in the servo control mode and reaches the target;

[0105] - Steady orange when the positioning system cannot detect the tracker in the servo control mode.

[0106] Such an LED ring is convenient because it can be seen regardless of the orientation of the end effector; however, the user interface can take any other form. For example, it can be a small display with a diagonal of one or two inches, which can be rotated anywhere around the robotic end effector.

[0107] The end effector holds a tool holder 2, which can be, for example, a linear and cylindrical guide for an active tool, such as a drill, to be held by the user. The guide allows the active tool to be maintained according to a determined orientation and a determined distance from the patient.

[0108] The tracker 12 is attached to the end effector and is used to determine the position and orientation of the end effector relative to the tracker attached to the patient. A high-speed three-dimensional camera is used to obtain such measurements, with a low latency of less than ten milliseconds and a frame rate in the range of one hundred hertz or higher.

[0109] Figure 3 An enlarged view of the end effector is shown.

[0110] Figure 4 An embodiment of a state machine that describes the operation of the control unit on the robotic arm is provided. The right part of the figure shows the different states of the LED ring that forms the user interface.

[0111] When the system is turned on, initialization (Initialization) is performed.

[0112] The first step is to select the next goal to be achieved. The selection can be made by the user during the planning step. Or otherwise, as described above, the selection can be made by double-clicking the second switch.

[0113] Then, the robotic arm is in the idle mode, waiting for the user's input. The LED emits a flashing white light.

[0114] If the user activates the first switch (press the main input), the robotic arm enters the manual guidance mode and maintains this mode as long as the first switch is activated. When the user releases the first switch (release the main input), the robotic arm returns to the idle mode.

[0115] If the user activates the second switch (press the secondary input), the robotic arm enters the calculated trajectory mode and moves to the selected goal. This mode can only be activated when the tracker attached to the end effector can be detected by the positioning system (event tracker visible). The calculated trajectory goal is maintained as long as the goal has not been reached and the second switch is activated. In this state, the LED emits a steady white light.

[0116] If the user releases the second switch and the goal has not been reached yet (release the secondary input), the robotic arm returns to the idle mode.

[0117] If the goal has been reached (this situation is detected by the control unit by comparing the position of the goal and the position of the tracker attached to the end effector), the LED emits a steady green light.

[0118] Therefore, the user must release the second switch to enter the servo control (Servo) mode.

[0119] During the servo control mode, the control unit continuously monitors whether the tracker attached to the end effector is within the field of view of the positioning system (tracker visible loop). If the positioning system cannot detect the tracker (event tracker not visible), the servo control mode is interrupted and the LED emits a steady orange light. The robotic arm enters the waiting for tracker mode until the tracker becomes detectable again (event tracker visible). Therefore, the robotic arm returns to the servo control mode and the LED emits a steady green light again.

[0120] If the control unit detects an unmet safety condition, such as the movement of the robotic arm exceeding a predetermined amplitude, direction, acceleration, and / or speed in the servo control mode, the control unit activates the safety mode that prohibits the movement of the robotic arm (event activate safety mode), and the robotic arm returns to the idle mode.

[0121] References

[0122] US 2011 / 0190790

[0123] US 2014 / 0350571

[0124] EP2868277

[0125] EP3361977

Claims

1. A surgical robot system, comprising a robotic arm (1) holding an end effector (11) and a control unit (13), the control unit being configured to controllably move the robotic arm and maintain the end effector (11) in at least one target position relative to a patient, wherein, The control unit is configured to: (i) Activate a manual guidance mode based on a first input continuously applied by a user to the robotic arm (1), wherein the robotic arm can be freely moved by the user; (ii) Activate a computed trajectory mode based on a second input different from the first input continuously applied by the user to the robotic arm (1), wherein the robotic arm moves to a target position according to the computed trajectory; (iii) When the computed trajectory mode is activated, detect that the end effector (11) satisfies at least one predetermined safety condition and automatically switch to a servo control mode, wherein the robotic arm (1) can automatically move to maintain the end effector (11) at a target position relative to a tracker attached to a patient.

2. The surgical robot system according to claim 1, wherein, The target position is selected according to the following parameters: - The drilling axis; - The drilling axis and the drilling depth; - The cutting plane; - The optimal working position of the active surgical tool.

3. The surgical robot system according to claim 1, wherein, The predetermined safety condition is that a tracker attached to the patient remains within a controlled volume relative to the base of the robotic arm, and the dimensions of the controlled volume are larger in the expected movement direction of the tracker than in the non-expected movement direction of the tracker.

4. The surgical robot system according to claim 1, wherein, The control unit is configured to adjust the computed trajectory based on the orientation applied by the user to the robotic arm (1) in the manual guidance mode.

5. The surgical robot system according to claim 1, further comprising a user interface coupled to the control unit and configured to provide information about the current mode.

6. The surgical robot system according to claim 5, wherein, The user interface includes a display monitor that is disposed on the robotic arm and configured to display changing graphical items according to the current mode.

7. The surgical robot system according to claim 5, wherein, The user interface includes a ring (3) that includes a plurality of LEDs configured to have a predetermined color and / or blinking state according to the current mode.

8. The surgical robot system according to claim 1, wherein, The control unit is further configured to activate a safety mode that prohibits movement of the robotic arm based on detecting that the movement of the robotic arm (1) exceeds a predetermined amplitude, direction, acceleration, and / or speed in the servo control mode.

9. The surgical robot system according to claim 1, wherein, The control unit is configured to continuously maintain the end effector (11) at a plurality of target positions.

10. The surgical robot system according to claim 1, further comprising a first switch (4) configured for the user to apply a first input and a second switch (5) different from the first switch and configured for the user to apply a second input.

11. The surgical robot system according to claim 10, wherein, The control unit is configured to be able to switch between two consecutive targets when the user double-clicks the second switch at any time during the surgery.

12. The surgical robot system according to any one of claims 1 to 11, wherein, The control unit is configured to place the robotic arm (1) in an idle mode when tracking of the robotic arm is not enabled and the surgical robot system is in the manual guidance mode or the computed trajectory mode.

13. The surgical robot system according to any one of claims 1 to 11, wherein, The control unit is configured to place the robotic arm in a specific waiting mode when tracking of the robotic arm is lost while the surgical robot system is in servo control mode, wherein when the tracking is restored, the specific waiting mode can be switched back to servo control mode.

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