Method and system for joint magnetic brake engagement and disengagement

Abstract

A method performed by a surgical robotic system. While a magnetic brake of the surgical robotic system is engaged such that a joint of a robotic arm of the system is locked in place, power is applied to the magnetic brake. The system measures an input current of the magnetic brake and determines whether the input current includes any peaks. The system determines a status of the magnetic brake based on the determining of whether the input current includes any peaks and a notification is provided indicating the status.

Description

Atorney Docket No. : AUR6356WOPCT1Electronically FiledMethod and System for Joint Magnetic Brake Engagement and Disengagement RELATED APPLICATION

[0001] This patent application claims the benefit of the earlier filing date of U.S. Provisional Patent Application 63 / 695,279 filed September 16, 2024, which is incorporated herein by reference in its entirety.FIELD

[0002] Various embodiments of the disclosure relate generally to surgical systems, and more specifically to a surgical system for monitoring and controlling engagement and disengagement of a magnetic brake of a robotic arm joint. Other embodiments are also described.BACKGROUND

[0003] Minimally-invasive surgery, MIS, such as laparoscopic surgery, uses techniques that are intended to reduce tissue damage during a surgical procedure. Laparoscopic procedures typically call for creating a number of small incisions in the patient, e.g., in the abdomen, through which several surgical tools such as an endoscope, a blade, a grasper, and a needle, are then inserted into the patient. A gas is injected into the abdomen which insufflates the abdomen thereby providing more space around the tips of the tools, making it easier for the surgeon to see (via the endoscope) and manipulate tissue at the surgical site. MIS can be performed faster and with less surgeon fatigue using a surgical robotic system in which the surgical tools are operatively attached to the distal ends of robotic arms, and a control system actuates the arm and its attached tool. The tip of the tool will mimic the position and orientation movements of a handheld user input device (UID) as the latter is being manipulated by the surgeon. The surgical robotic system may have multiple surgical arms, one or more of which has an attached endoscope, and others have attached surgical instruments for performing certain surgical actions.

[0004] Control inputs from a user (e.g., surgeon or other operator) are captured via one or more user input devices and then translated into control of the robotic system. For example, in response to user commands, a tool drive having one or more motors may actuateAtorney Docket No. : AUR6356WOPCT1Electronically Filed one or more degrees of freedom of a surgical tool when the surgical tool is positioned at the surgical site in the patient.SUMMARY

[0005] Robotic manipulators of a surgical robotic system, such as robotic arms that include surgical tools, may be equipped with a motor (or actuator) and a brake at their joints. Such brakes may be magnetic brakes, where, by default, the brakes may be engaged, keeping the robotic joints locked when no current is supplied to the brakes. To initiate motion at a joint, before providing current to move the motor, the brake needs to be disengaged. In particular, the joint brake may be disengaged by providing current to the brake. Once disengaged, the motor may be controlled to move the joint. Conversely, after the motion of a joint concludes (e.g., rotating a robotic manipulator), removing the current from the brake may cause it to re-engage, thereby securing the manipulator structurally. Successful engagement and disengagement of magnetic brakes relies on the movement of a magnetic disk, which may face obstacles due to factors such as wear and tear, deformation of components, and contamination affecting gap dimensions between the magnetic disk and a housing of the magnetic brake. Therefore, there is a need for monitoring mechanisms or additional sensors to confirm the functional state of the brake.

[0006] According to one embodiment of the disclosure, a method performed by a surgical robotic system, the method includes: while a magnetic brake of the surgical robotic system is engaged such that a joint of a robotic arm of the surgical robotic system is locked in place, applying power to the magnetic brake; measuring an input current of the magnetic brake; determining whether the input current includes any peaks; determining a status of the magnetic brake based on the determining of whether the input current includes any peaks; and providing a notification indicating the status of the magnetic brake.

[0007] In one embodiment, the magnetic brake includes a brake housing, a ferromagnetic plate, and a coil, where the magnetic brake is engaged when the ferromagnetic plate is in contact with the brake housing, where applying power includes supplying a current to the coil to produce a magnetic field to cause the ferromagnetic plate to disengage from the brake housing. In some embodiments, the magnetic field is a first magnetic field, where brake housing includes a permanent magnet that is arranged to produce a second magnetic field to pull the ferromagnetic plate towards the brake housing, where the first magnetic fieldAtorney Docket No. : AUR6356WOPCT1Electronically Filed causes the ferromagnetic plate to disengage by canceling or reducing the second magnetic field. In another embodiment, responsive to a determination that the input current includes one peak, the status of the magnetic brake is disengaged such that the ferromagnetic plate is no longer in contact with the brake housing. In some embodiments, the method further includes determining whether the one peak has a magnitude that is greater than a threshold, where responsive to a determination that the one peak has the magnitude that is less than the threshold, the status of the magnetic brake is a slow disengagement in which the ferromagnetic plate separates from the brake housing over a period of time. In another embodiment, responsive to a determination that the one peak has the magnitude that is greater than the threshold, the status of the magnetic brake is a disengagement in which the ferromagnetic plate separates from the brake housing within the period of time. In some embodiments, the method further includes, responsive to the status of the magnetic brake being disengaged, providing a control signal to a motor of the joint to move at least a portion of the robotic arm.

[0008] In one embodiment, the magnetic brake includes a disk and a brake housing, where, responsive to a determination that the input current includes two or more peaks, the status of the magnetic brake indicates that the disk is misaligned along at least one axis with respect to the brake housing. In another embodiment, the method of any preceding claim further includes, responsive to a determination that the input current includes only one peak, determining whether an amplitude of the peak is greater than a threshold, where, responsive to the amplitude being greater than the threshold, the status of the magnetic brake indicates that the magnetic brake performed a single discrete movement in less than a time threshold to disengage, and where, responsive to the amplitude being less than the threshold, the status of the magnetic brake indicates that the magnetic brake performed the single discrete movement longer than the time threshold to disengage. In another embodiment, providing the notification includes displaying a visual notification on a display of the surgical robotic system or playing back an audible notification on one or more speakers of the surgical robotic system.

[0009] In one embodiment, the method further includes activating a motor of the joint to move the robotic arm responsive to the status of the magnetic brake indicating that the magnetic brake is disengaged. In another embodiment, the method further includes: receiving input indicating that the magnetic brake is to transition from being disengaged to engaged;Atorney Docket No. : AUR6356WOPCT1Electronically Filed responsive to the input, putting the motor into a position holding mode; ceasing to apply the power to the magnetic brake; determining whether the status of the magnetic brake indicates that the magnetic brake is engaged; and responsive to determining that the status of the magnetic brake indicates that the magnetic brake is engaged, deactivating the motor. In another embodiment, responsive to determining that the status of the magnetic brake indicates that the magnetic brake is not engaged, providing a notification indicating that the status of the magnetic brake as an unsuccessful engagement; and maintaining the motor in the position holding mode. In some embodiments, the method further includes: iteratively applying the power and ceasing to apply the power to the magnetic brake to determine whether the status of the magnetic brake changes from disengaged to engaged; at each iteration, determining whether a number of iterations exceeds a threshold; responsive to the number of iterations exceeding the threshold, providing a notification indicating the status of the magnetic brake as an unsuccessful engagement.

[0010] According to another embodiment of the disclosure, a method performed by a surgical robotic system, the method includes: applying power to a magnetic brake of a robotic component of the surgical robotic system; determining that the magnetic brake has disengaged responsive to the applied power; determining an input current at which the magnetic brake disengaged based on the applied power; and adjusting the applied power to the magnetic brake based on the input current, while the magnetic brake remains disengaged.

[0011] In one embodiment, applying the power includes incrementally increasing the power applied to the magnetic brake until it is determined that the magnetic brake has disengaged. In another embodiment, determining the input current includes detecting a peak of the input current, where the applied power is adjusted based on the peak. In some embodiments, applying the power includes supplying an initial current to the magnetic brake, where adjusting the applied power includes reducing the power based on a difference between the peak of the input current and the initial current. In another embodiment, the magnetic brake includes a disk, a brake housing, and a coil, where the magnetic brake disengages when the disk moves away from the brake housing due to a magnetic field produced by the coil responsive to the applied power. In some embodiments, applying the power includes applying a voltage to the coil of the magnetic brake, where adjusting the applied power includes reducing the voltage based on the input current and a resistance of the coil.Atorney Docket No. : AUR6356WOPCT1Electronically Filed

[0012] In one embodiment, the method further includes: measuring one or more characteristics of the magnetic brake; determining a temperature of the magnetic brake based on the one or more characteristics; and responsive to the temperature being greater than a threshold, ceasing to apply the power to the magnetic brake. In another embodiment, the one or more characteristics includes an applied voltage to the magnetic brake, where the temperature is determined based on the input current and the applied voltage. In some embodiments, the method further includes: receiving sensor data from one or more sensors of the surgical robotic system; determining that the magnetic brake is disengaged based on the sensor data; and providing a notification indicating that the magnetic brake is disengaged. In another embodiment, the magnetic brake includes a disk and a brake housing, where determining that the magnetic brake is disengaged includes determining that there is a gap between the disk and the brake housing that includes a width that is greater than a threshold based on the sensor data. In some embodiments, the one or more sensors includes at least one of an image capturing device, a proximity sensor, and a contact sensor.

[0013] According to another embodiment of the disclosure, a method performed by a surgical robotic system, the method includes: ceasing to apply power to a magnetic brake to transition the magnetic brake from being disengaged to engaged; measuring an input current of the magnetic brake; determining whether the magnetic brake has successfully engaged based on the input current; and providing a notification indicating a status of the magnetic brake as being engaged.

[0014] In one embodiment, the magnetic brake is part of a joint that includes a motor for moving a portion of a robotic arm, where the method further includes putting the motor into a position holding mode to prevent the portion of the robotic arm from moving. In another embodiment, the method further includes, responsive to a determining that the magnetic brake has successfully engaged, deactivating the motor. In some embodiments, the method further includes cycling between applying the power and ceasing to apply power to the magnetic brake for at least a period of time, where responsive to failing to determine that the magnetic brake has successfully engaged within the period of time, the magnetic brake is determined to have unsuccessfully engaged. In another embodiment, cycling includes a number of attempts to successfully engage the magnetic brake, where the notification is provided after the number of attempts exceeds a predefined threshold. In another embodiment, the magnetic brake includes a brake housing, a disk, and a coil, where theAtorney Docket No. : AUR6356WOPCT1Electronically Filed magnetic brake is engaged when the disk is in contact with the brake housing, supplying power to the magnetic brake causes the coil to produce a magnetic field to cause the disk to disengage from the brake housing. In some embodiments, determining whether the magnetic brake has successfully engaged includes determining whether the input current includes at least one peak responsive to the power ceasing to be supplied.

[0015] According to another embodiment of the disclosure, a surgical robotic system includes: a robotic component that includes a joint with a magnetic brake; at least one processor; and memory having instructions which when executed by the at least one processor causes the surgical robotic system to: supply power to a coil of the magnetic brake of the robotic component in order to disengage the magnetic brake from an engaged state, detect an input current of the coil; detect a peak within the input current; adjust the power supplied to the coil based on the detected peak, where the magnetic brake remains disengaged while the power is adjusted.

[0016] In one embodiment, the memory has further instructions to increase the power supplied to the coil until the peak is detected within the input current. In another embodiment, the power is supplied by providing a current to the coil, where adjusting the power supplied includes reducing the supplied power based on a difference between the peak within the input current and the provided current to the coil. In some embodiments, the memory has further instructions to provide a notification indicating a status of the magnetic brake as being successfully disengaged based on the detected peak within the input current.

[0017] In one embodiment, the peak is a first peak, the memory has further instructions to detect a second peak that is subsequent to the first peak, the power is adjusted based on a difference between the second peak within the input current and a current value associated with the supplied power. In some embodiments, the memory has further instructions to provide a notification indicating that a disk of the magnetic brake is misaligned along at least one axis. In another embodiments, the memory has further instructions to increase power supplied to the coil until either 1) a determination has been made that the magnetic brake has successfully disengaged based on the detected peak within the input current or 2) a duration to disengage the magnetic brake has exceeded a threshold.

[0018] According to another embodiment of the disclosure, a surgical robotic system comprising: a robotic arm that includes a joint and a magnetic brake that includes aAtorney Docket No. : AUR6356WOPCT1Electronically Filed permanent magnet and a ferromagnetic plate; at least one processor; and memory having instructions which when executed by the at least one processor causes the surgical robotic system to: apply power to the magnetic brake to cause the ferromagnetic plate to be disengaged from the permanent magnet, thereby allowing the joint to move the robotic arm; provide a control signal to a motor of the joint to move the robotic arm; cease applying the power to the magnetic brake to cause the ferromagnetic plate to be engaged with the permanent magnet, thereby preventing the joint from moving the robotic arm; measure an input current of the magnetic brake as a function of time; determine whether the input current includes one or more peaks; determine a status of the magnetic brake based on a determination of whether the input current includes one or more peaks; and provide a notification that indicates the status of the magnetic brake.

[0019] In one embodiment, the memory has further instructions to put the motor of the joint into a position holding mode prior to ceasing the supply of power to the magnetic brake. In some embodiments, responsive to determining that the status of the magnetic brake indicates that the brake has engaged, deactivating the motor. In another embodiment, responsive to determining that the input current comprises two peaks, determining the status of the magnetic brake as a misaligned successful engagement.

[0020] According to another embodiment of the disclosure, a system or an electronic device as shown and as described herein. According to another embodiment of the disclosure, a method substantially as herein described. According to another embodiment of the disclosure, a processor configured to perform one or more operations as described herein. According to another embodiment of the disclosure is a non-transitory machine-readable medium that includes instructions which when executed by at least one processor causes a system to perform one or more operations as described herein.

[0021] The above summary does not include an exhaustive list of all embodiments of the disclosure. It is contemplated that the disclosure includes all systems and methods that can be practiced from all suitable combinations of the various embodiments summarized above, as well as those disclosed in the Detailed Description below and particularly pointed out in the claims. Such combinations may have particular advantages not specifically recited in the above summary.Atorney Docket No. : AUR6356WOPCT1Electronically FiledBRIEF DESCRIPTION OF THE DRAWINGS

[0022] The embodiments are illustrated by way of example and not by way of limitation in the figures of the accompanying drawings in which like references indicate similar elements. It should be noted that references to "an" or “one” embodiment of this disclosure are not necessarily to the same embodiment, and they mean at least one. Also, in the interest of conciseness and reducing the total number of figures, a given figure may be used to illustrate the features of more than one embodiment, and not all elements in the figure may be required for a given embodiment.

[0023] Fig. 1 shows a pictorial view of an example surgical system in an operating arena.

[0024] Fig. 2 shows an example of a robotic arm that includes several joints and links according to one embodiment of the disclosure.

[0025] Fig. 3 shows a joint magnetic brake of a robotic arm joint that is disengaged and engaged according to one embodiment of the disclosure.

[0026] Fig. 4 is a block diagram of the surgical system according to one embodiment.

[0027] Fig. 5 is a flowchart of one embodiment of a process for determining a status of a magnetic brake of a joint of a robotic arm.

[0028] Figs. 6A and 6B is a flowchart of one embodiment of a process for disengaging a joint magnetic brake.

[0029] Figs. 7A - 7D show several curves of characteristics of the joint magnetic brake based on the brake’s disengagement status according to one embodiment of the disclosure.

[0030] Fig. 8 is a flowchart of one embodiment of a process for maintaining a minimum necessary applied current for disengaging the joint magnetic brake.

[0031] Fig. 9 shows several graphs illustrating comparisons of characteristics of the joint magnetic brake when the minimum necessary applied current is applied to the jointAtorney Docket No. : AUR6356WOPCT1Electronically Filed magnetic brake and when a maximum voltage is applied to the joint magnetic brake to disengage the brake.

[0032] Fig. 10 is a flowchart of one embodiment of a process for engaging the magnetic brake of the joint of the robotic arm.

[0033] Fig. 11A - 11D show several curves of characteristics of the joint magnetic brake based on the brake’s engagement status according to one embodiment of the disclosure.Atorney Docket No. : AUR6356WOPCT1Electronically FiledDETAILED DESCRIPTION

[0034] Several embodiments of the disclosure with reference to the appended drawings are now explained. Whenever the shapes, relative positions and other embodiments of the parts described in a given embodiment are not explicitly defined, the scope of the disclosure here is not limited only to the parts shown, which are meant merely for the purpose of illustration. Also, while numerous details are set forth, it is understood that some embodiments may be practiced without these details. In other instances, well-known circuits, structures, and techniques have not been shown in detail so as not to obscure the understanding of this description. Furthermore, unless the meaning is clearly to the contrary, all ranges set forth herein are deemed to be inclusive of each range’s endpoints.

[0035] Fig. 1 shows a pictorial view of an example (e.g., laparoscopic) surgical system (which hereafter may be referred to as “system”) 10 in an operating arena. The system 10 includes a user console 12, a control tower 13, and one or more surgical robotic arms 14 at a surgical robotic table (surgical table or surgical platform) 15. In one embodiment, the arms 14 may be mounted to a table or bed on which the patient rests as shown in the example of Fig. 1. In one embodiment, at least some of the arms 14 may be configured differently. For example, at least some of the arms may be mounted on a ceiling, sidewall, or in another suitable structural support, such as a cart separate from the table. The system 10 can incorporate any number of devices, tools, or accessories used to perform surgery on a patient 16. For example, the system 10 may include one or more surgical tools (instruments) 17 used to perform surgery (surgical procedure). A surgical tool 17 may be an end effector that is attached to a distal end of a surgical arm 14, for executing a surgical procedure.

[0036] Each surgical tool 17 may be manipulated manually, robotically, or both, during the surgery. For example, the surgical tool 17 may be a tool used to enter, view, or manipulate an internal anatomy of the patient 16. In an embodiment, the surgical tool 17 is a grasper that can grasp tissue of the patient. The surgical tool 17 may be controlled manually, by a bedside operator 18; or it may be controlled robotically, via actuated movement of the surgical robotic arm 14 to which it is attached. For example, when manually controlled an operator may (e.g., physically) hold a portion of the tool (e.g., a handle), and may manually control the tool by moving the handle and / or pressing one or more input controls (e.g.,Atorney Docket No. : AUR6356WOPCT1Electronically Filed buttons) on the (e.g., handle of the) tool. In another embodiment, when controlled robotically, the surgical system may manipulate the surgical tool-based user input (e.g., received via the user console 12, as described herein).

[0037] Generally, a remote operator 19, such as a surgeon or other operator, may use the user console 12 to remotely manipulate the arms 4 and / or the attached surgical tools 17, e.g., during a teleoperation. The user console 12 may be located in the same operating room as the rest of the system 10, as shown in Fig. 1. In other environments however, the user console 12 may be located in an adjacent or nearby room, or it may be at a remote location, e.g., in a different building, city, or country. The user console 12 may include one or more components, such as a seat 119, one or more foot-operated controls (or foot pedals) 130, one or more (handheld) user-input devices (UIDs) 140, and at least one display 150. The display is configured to display, for example, a view of the surgical site inside the patient 16. The display may be configured to display image data (e.g., still images and / or video). In one embodiment, the display may be any type of display, such as a liquid crystal display (LCD), a light-emitting diode (LED) display, an organic LED (OLED) display, etc. In some embodiments, the display may be a 3D immersive display that is for displaying 3D (surgical) presentations. For instance, during a surgical procedure one or more endoscopic cameras may be capturing image data of a surgical site, which the display presents to the user in 3D. In one embodiment, the 3D display may be an autostereoscopic display that provides 3D perception to the user without the need for special glasses. As another example, the 3D display may be a stereoscopic display that provides 3D perception with the use of glasses (e.g., via active shutter or polarized).

[0038] In another embodiment, the display 150 may be configured to display at least one graphical user interface (GUI) that may provide informative and / or interactive content, to thereby assist a user in performing a surgical procedure with one or more instruments in the surgical system 10. For example, some of the content displayed may include image data captured by one or more endoscopic cameras, as described herein. In another embodiment, the GUI may include selectable UI items, which when manipulated by the user may cause the system to perform one or more operations. For instance, the GUI may include a UI item as interactive content to switch control between robotic arms. In one embodiment, to interact with the GUI, the system may include input devices, such as a keyboard, a mouse, etc. In another embodiment, the user may interact with the GUI using the UID 140. For instance, theAtorney Docket No. : AUR6356WOPCT1Electronically Filed user may manipulate the UID to navigate through the GUI, (e.g., with a cursor), and to make a selection may hover the cursor over a UI item and manipulate the UID (e.g., selecting a control or button). In some embodiments, the display may be a touch-sensitive display screen. In this case, the user may perform a selection by navigating and selecting through touching the display. In some embodiments, any method may be used to navigate and / or select a UI item.

[0039] As shown, the remote operator 19 is sitting in the seat 119 and viewing the user display 150 while manipulating a foot-operated control 130 and a handheld UID 140 in order to remotely control one or more of the arms 14 and the surgical tools 17 (that are mounted on the distal ends of the arms 14.)

[0040] In some variations, the bedside operator 18 may also operate the system 10 in an “over the bed” mode, in which the bedside operator 18 (user) is now at a side of the patient 16 and is simultaneously manipulating a robotically-driven tool (end effector as attached to the arm 14), e.g., with a handheld UID 140 held in one hand, and a manual laparoscopic tool. For example, the bedside operator’s left hand may be manipulating the handheld UID to control a robotic component, while the bedside operator’s right hand may be manipulating a manual laparoscopic tool. Thus, in these variations, the bedside operator 18 may perform both robotic-assisted minimally invasive surgery and manual laparoscopic surgery on the patient 16.

[0041] During an example procedure (surgery), the patient 16 is prepped and draped in a sterile fashion to achieve anesthesia. Initial access to the surgical site may be performed manually while the arms of the system 10 are in a stowed configuration or withdrawn configuration (to facilitate access to the surgical site.) Once access is completed, initial positioning or preparation of the system 10 including its arms 14 may be performed. Next, the surgery proceeds with the remote operator 19 at the user console 12 utilizing the foot- operated controls 130 and the UIDs 140 to manipulate the various end effectors and perhaps an imaging system, to perform the surgery. Manual assistance may also be provided at the procedure bed or table, by sterile-gowned bedside personnel, e.g., the bedside operator 18 who may perform tasks such as retracting tissues, performing manual repositioning, and tool exchange upon one or more of the robotic arms 14. Non-sterile personnel may also be present to assist the remote operator 19 at the user console 12. When the procedure orAtorney Docket No. : AUR6356WOPCT1Electronically Filed surgery is completed, the system 10 and the user console 12 may be configured or set in a state to facilitate post-operative procedures such as cleaning or sterilization and healthcare record entry or printout via the user console 12.

[0042] In one embodiment, the remote operator 19 holds and moves the UID 140 to provide an input command to drive (move) one or more robotic arm actuators 170 (or driving mechanism) in the system 10 for teleoperation. The UID 140 may be communicatively coupled to the rest of the system 10, e.g., via a console computer system 160 (or host). The UID 140 can generate spatial state signals corresponding to movement of the UID 140, e.g., position and orientation of the handheld housing of the UID, and the spatial state signals may be input signals to control motions of the robotic arm actuators 170. The system 10 may use control signals derived from the spatial state signals, to control proportional motion of the actuators 170. In one embodiment, a console processor of the console computer system 160 receives the spatial state signals and generates the corresponding control signals. Based on these control signals, which control how the actuators 170 are energized to drive a segment or link of the arm 14, the movement of a corresponding surgical tool that is attached to the arm may mimic the movement of the UID 140. Similarly, interaction between the remote operator 19 and the UID 140 can generate, for example, a grip control signal that causes a jaw of a grasper of the surgical tool 17 to close and grip the tissue of patient 16.

[0043] The system 10 may include several UIDs 140, where respective control signals are generated for each UID that control the actuators and the surgical tool (end effector) of a respective arm 14. For example, the remote operator 19 may move a first UID 140 to control the motion of an actuator 170 that is in a left robotic arm, where the actuator responds by moving linkages, gears, etc., in that arm 14. Similarly, movement of a second UID 140 by the remote operator 19 controls the motion of another actuator 170, which in turn drives other linkages, gears, etc., of the system 10. The system 10 may include a right arm 14 that is secured to the bed or table to the right side of the patient, and a left arm 14 that is at the left side of the patient. An actuator 170 may include one or more motors that are controlled so that they drive the rotation of a joint of the arm 14, to for example change, relative to the patient, an orientation of an endoscope or a grasper of the surgical tool 17 that is attached to that arm. Motion of several actuators 170 in the same arm 14 can be controlled by the spatial state signals generated from a particular UID 140. The UIDs 140 can also control motion of respective surgical tool graspers. For example, each UID 140 can generate a respective gripAtorney Docket No. : AUR6356WOPCT1Electronically Filed signal to control motion of an actuator, e.g., a linear actuator that opens or closes jaws of the grasper at a distal end of surgical tool 17 to grip tissue within patient 16.

[0044] In some embodiments, the communication between the surgical robotic table 15 and the user console 12 may be through a control tower 13, which may translate user commands that are received from the user console 12 (and more particularly from the console computer system 160) into robotic control commands that transmitted to the arms 14 on the surgical table 15. The control tower 13 may also transmit status and feedback from the surgical table 15 back to the user console 12. The communication connections between the surgical table 15, the user console 12, and the control tower 13 may be via wired (e.g., optical fiber) and / or wireless links, using any suitable one of a variety of wireless data communication protocols, such as BLUETOOTH protocol. Any wired connections may be optionally built into the floor and / or walls or ceiling of the operating room. The system 10 may provide video output to one or more displays, including displays within the operating room as well as remote displays that are accessible via the Internet or other networks. The video output or feed may also be encrypted to ensure privacy and all or portions of the video output may be saved to a server or electronic healthcare record system.

[0045] Fig. 2 shows an example of a robotic arm 14 that includes several joints and links according to one embodiment of the disclosure. In particular, this figure shows the arm 14 having links 20 connected by joints 21, where each joint may be capable of rotating about and / or translating along one or more axes. The arm also includes a tool drive 22 that may be a part of or coupled to a surgical tool, where the tool drive may be configured to move a surgical instrument during a surgical procedure.

[0046] As shown, the robotic arm 14 includes seven links 20a-20g and seven joints 21a-21g. In particular, joint 21a couples link 20b and link 20a together, joint 21b couples link 20b and link 20c together, joint 21c couples link 20c and link 20d together, joint 2 Id couples link 20d and link 20e together, joint 21e couples link 20e and link 20f together, joint 2 If couples link 20f and link 20g together, and joint 21g couples link 20g and the tool drive 22 together. In one embodiment, the robotic arm may include more or fewer links and / or joints. In one embodiment, each joint may include one or more motors that allow the joint to rotate around and / or translate along one or more axes. For example, joint 2 lb may be arranged to rotate link 20c about an axis with respect to the link 20b, where the axis may run throughAtorney Docket No. : AUR6356WOPCT1Electronically Filed both links. Conversely, joint 21c may be arranged to rotate link 20d about an orthogonal axis to the axis that runs through links 20c and 20b, with respect to the link 20c.

[0047] Each joint may also include a brake that pauses or locks movement of a corresponding joint. In one embodiment, the brake may be a magnetic brake, an example of which is illustrated in Fig. 3. During operation, while the brake of joint 21a is disengaged, due to one or more control signals of the robotic system for example, the joint 21a may be capable of being moved (e.g., based on a user command) such that the link 20b (and the remaining portion of the robotic arm) may be rotated about one or more axes with respect to link 20a. As described herein, this may allow a user to move the arm based on user input into one or more UIDs. When the brake of joint 21a is engaged, however, the joint 21a may be locked to prevent movement of the link 20b with respect to link 20a.

[0048] Fig. 3 shows a joint magnetic brake 32 of a joint 21 that transitions from being engaged to disengaged according to one embodiment of the disclosure. Specifically, this figure shows a cross-section of the magnetic brake. The joint 21 that may be one or more of the joints 21a-21g of the robotic arm 14, as described herein. The joint 21 may include the magnetic brake 32 and a motor (or actuator) 33.

[0049] This figure shows two stages, where the first stage 30 illustrates an example of the magnetic brake 32 being engaged and the second stage 31 illustrates an example of the magnetic brake being disengaged. Each stage also shows a power source 34 that may be (electrically) coupled to the magnetic brake 32 and a switch 39 that may be coupled between the power source 34 and the brake 32. In one embodiment, these components may be a part of the surgical system 10 and / or may be separate from (or a part of) the j oint 21. For instance, the power source 34 may be a direct current (DC) power supply of the surgical system which may be arranged to supply power as an input voltage, Fi„, and an input current, Im, of the magnetic brake 32. In one embodiment, the power supply may be arranged to supply power to the magnetic brake based on control signals from the surgical system. In particular, control signals may be supplied by a controller, such as controller 48 of Fig. 4. More about the controller is described herein.

[0050] The magnetic brake 32 includes a disk (or plate) 35 and a brake housing 36 that includes a coil 45. The disk 35 may be a ferromagnetic disk that may be arranged to come into contact with the brake housing, while the magnetic brake is engaged. More aboutAtorney Docket No. : AUR6356WOPCT1Electronically Filed engagement is described herein. The disk 35 may be coupled to a shaft 38 that may be coupled to the motor 33. As shown, the shaft 38 may pass through an opening within the brake housing 36 and the coil 45. For example, the brake housing may be a cylinder with a hole that passes through a middle (or center) of the cylinder, for example torus-shaped. The coil 45 may be embedded or inside the brake housing, and may also be a cylinder. The brake housing may be dimensioned such that the shaft 38 may pass through the middle of the brake housing 36 (and the coil 45) with little or no frictional resistance along the inside of the brake housing. As shown, the coil may be arranged inside the brake housing. In another embodiment, the coil may be arranged differently, such as being on the outside of the brake housing. The motor 33 may be arranged to rotate the shaft 38 along the Z-axis, in response to a control signal, for example. As the shaft rotates, one or more links that may be coupled to the joint 21 may also rotate or move.

[0051] The first stage 30 shows the magnetic brake 32 as being engaged. In particular, input power is not supplied (or power may be supplied below a threshold) by the power source 34 to the (internal coil 45 of the) magnetic brake. As a result, the disk has coupled with (e.g., come into contact with) the brake housing. The magnetic disk may be engaged when the disk comes into contact with the brake housing. In one embodiment, the disk may come into contact with the housing through magnetic attraction. For example, the brake housing may include a magnet, which may magnetically draw (or attract) the disk 35 towards the brake housing until it comes into direct contact with a top surface of the housing. In one embodiment, this internal magnet (not shown) may be a permanent magnet. In another embodiment, the internal magnet may be an electromagnetic, which may be energized when the brake is deemed by the system 10 to be engaged. In another embodiment, the disk may come into contact with the brake housing via a mechanical force. For instance, the magnetic brake may include one or more springs, which may pull the disk 35 towards the brake housing, while the coil 45 is not energized. As another example, the disk may be drawn towards the brake housing by energizing another internal coil (not shown) within the brake housing. For instance, while the magnetic brake is engaged, the coil 45 may be deenergized, while another coil (e.g., within the brake housing 36 or within the disk 35) may be energized, thereby attracting the disk to the brake housing.

[0052] With this coupling of the disk with the brake housing, the disk, and the shaft 38 may be held in place due to frictional force between the brake housing 36 and the disk 35,Atorney Docket No. : AUR6356WOPCT1Electronically Filed thereby preventing the shaft 38 from rotating about the Z-axis. In one embodiment, the disk 35 may be coupled to the shaft via a spring or any flexible (or movable) element (or material), which may allow the disk to move towards and come into contact with the brake housing, as described here, in order to prevent movement of the shaft 38 as the disk moves towards (and comes in contact with) the brake housing. Thus, the disk may be capable of moving along the Z-axis independently from the shaft, while both are required to rotate together about the Z-axis.

[0053] As described herein, the magnetic brake 32 may engage based on user input or lack thereof. For example, to engage the brake, a user of the surgical system may release (or not provide input into) a clutch mechanism, which may be a part of an input device, such as the UID 140 or foot pedal 130. In response, the switch 39 may be opened, thereby preventing current from flowing into the brake. As another example, in lieu of or in addition to the switch 39, the surgical system may engage (and / or disengage) the brake by controlling the input power supplied by the power source 34. For instance, to engage the brake, the power source 34 may controlled to not supply V . In which case, the switch 39 may be an optional component. Conversely, to disengage the brake, the user may provide input to (e.g., hold) the clutch mechanism. In one embodiment, to disengage the brake, the user may provide an opposite input as the input provided to engage the brake. More about engaging and disengaging the brake is described herein.

[0054] The second stage 31 shows the magnetic brake as being disengaged, thereby allowing the shaft 38 and the disk 35 to rotate about the Z-axis, as shown by the two curved arrows. In this case, the switch 39 has been closed, which may be the result of a user engaging the clutch mechanism, thereby completing the circuit between the power source 34 and the joint to provide input power. In particular, the power source is supplying power such that the internal coil draws input current, lin, and is therefore energized to generate a magnetic field that may provide a pushing force to push the disk 35 away from the brake housing. In which case, the coil may be supplied current to produce a magnetic field to cause the disk to disengage (separate) from the brake housing. In another embodiment, this generated magnetic field may neutralize a magnetic field of a permanent magnet, which may be arranged to draw the disk 35 towards the brake housing, as shown in the first stage 30. For instance, the coil 45 may produce an inverse (e.g., a first) magnetic field to the (e.g., second) magnetic field produced by a permanent magnet that may be arranged to pull the disk towards the brakeAtorney Docket No. : AUR6356WOPCT1Electronically Filed housing, thereby countering or neutralizing the pulling forces caused by magnetic field of the permanent magnet. Specifically, the field produced by the coil may cause the disk to disengage by canceling or reducing the magnetic field of the permanent magnet. This reduction of the magnetic field may release the magnetic coupling between the disk 35 and the brake housing, causing the disk 35 to separate from the magnet housing 36. As a result, a gap 37 may be formed between the disk 35 and the brake housing 36, which allows the motor 33 to rotate the shaft 38.

[0055] As described herein, successful engagement and disengagement of magnetic brakes rely on the movement of a magnetic disk, which may face obstacles due to factors such as wear and tear, deformation of components, and contamination affecting gap dimensions between the magnetic disk and a magnet of the magnetic brake. In the absence of monitoring mechanisms or sensors to confirm the magnetic brake’s functional state, this may result in delayed detection of failures to engage or disengage. For example, delayed or missed detection of a brake engagement failure, whereby the magnetic brake may be controlled by a user to engage but fails to do so, may result in an unintended motion of the joint 21. In one embodiment, a brake engagement failure may be detected from observed displacement in joint encoders of the surgical system. This method, however, provides only a late detection as it requires some movement of the joint to have occurred already before the detection.Delayed or missed detection of a brake disengagement failure may cause wear and tear of the brake, which may eventually lead to the brake not effectively holding the position of the robotic arm, and therefore causing unintended motion of the arm. In one embodiment, a brake disengagement failure may potentially be detected through a spike in the motor current, but this again would be a late detection.

[0056] Robotic joints may be complex assemblies incorporating multiple mechanical and electrical components that participate in the joints’ capability to move or lock in position. The magnetic brake is just one of these components. In the case of joint issues, such as failure to lock or unlock, diagnosing the issue and identifying the root cause of the failure is not trivial. Operational failures, such as the arm’s inability to hold its position or move, may stem from various factors such as worn-out gearing, broken or slipping mechanical fasteners, or a malfunctioning magnetic brake. The brake may typically be located deep inside the joint, without visual access from outside the robotic joint. Without sensor feedback specifically on the brake, it may become impossible to ascertain if the brake alone is failing toAtorney Docket No. : AUR6356WOPCT1Electronically Filed disengage / engage without disassembling the joint. Therefore, there is a need for a system and method for monitoring the magnetic brakes functional state.

[0057] The present disclosure provides a method and system for monitoring joint magnetic brake engagement and disengagement. The method may be performed by the surgical system 10, where the status of the magnetic brake is determined based on the measured input current of the magnetic brake. For instance, while the magnetic brake is engaged such that the joint of the robotic arm is locked in place, power may be applied to the magnetic brake. In particular, power supplied by the power source 34 may be applied upon the internal coil of the brake housing. The system may measure the input current of the magnetic brake (e.g., Im), specifically the current of the internal coil 45. The system may determine whether the input current includes any peaks, which may be portions of the input current with amplitudes across a period of time that may exceed or meet a threshold. In particular, peaks may be the result of eddy currents that occur in response to the disk separating (e.g., making discrete steps) away from the brake housing 36). The system may determine the status of the magnetic brake based on determining whether any peaks exist, and may provide a notification indicating the status of the magnetic brake. For instance, when one big peak exists (e.g., a peak with an amplitude that is greater than a threshold amplitude) that may be an indication of a successful disengagement. Conversely, if no peak exists, this may be an indication of a disengagement failure. Continuous monitoring of the current input to the brake reveals a distinctive signature of a sharp change in current, which may allow the system to identify brake engagement / disengagement in real-time. As a result, the system 10 may efficiently provide an accurate indication of the status of the magnetic brake.

[0058] Fig. 4 is a block diagram of the surgical system 10 according to one embodiment. The system includes a controller 48, one or more joints 21, an input device 42, and one or more (optional) sensors 41. In one embodiment, the system may include more or less elements, such as having two or more sensors and / or joints, or not having any sensors 41. Although the elements are illustrated as being separate, at least some may be a part of (or integrated) with one another. For example, the controller 48 may be a part of the joint 21.

[0059] In one embodiment, the input device 42 may be any electronic device that may be arranged to receive user input and provide one or more control signals to the controller 48 based on that input. For example, the input device may be a foot pedal 130 or a UID 140. InAtorney Docket No. : AUR6356WOPCT1Electronically Filed particular, the input device may include a clutch mechanism, which when receiving user input (e.g., engaged by a user) may provide a control signal to the controller 48 to disengage the magnetic brake 32 of the joint 21. As an example, the clutch mechanism may be a button or a trigger, which when pressed or pulled, respectively, by the user may engage the clutch mechanism. Conversely, upon ceasing to receive user input (e.g., the user releasing the clutch mechanism), the input device 42 may cease providing the control signal to the controller 48, where the controller may be configured to engage the one or more magnetic brakes. In another embodiment, the input device may include a microphone, which may be arranged to capture sound of the environment. In which case, the controller 48 may receive input as a microphone signal that includes speech of a user, where the controller may determine the input based on speech recognition. In another embodiment, the input device 42 may include another input that is separate from the clutch mechanism for activating / deactivating the motor 33 ofthe joint 21.

[0060] The sensors 41 may include one or more sensors that are designed to produce sensor data based on sensing features of the environment. In one embodiment, the sensors may include a proximity sensor (e.g., a capacitive sensor, etc.) designed to sense or detect one or more objects and produce sensor data based on that detection. In particular, the sensor data produced by the proximity sensor may indicate a distance between the sensor and an object. In another embodiment, the sensors 41 may include an optical sensor, such as a camera arranged to capture one or more images (or video). In one embodiment, the sensors may be any type of sensor that may be designed to detect at least one of whether there is a gap 37 between the disk 35 and the brake housing 36, whether one or more components (e.g., the disk 35) is misaligned with respect to one or more other components, etc. In some embodiments, the sensors may include a temperature sensor arranged to measure the temperature of one or more components, such as the magnetic brake, of the surgical system 10.

[0061] In one embodiment, the controller 48 may be a special-purpose processor such as an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA), a general -purpose microprocessor, a digital signal controller, or a set of hardware logic structures (e.g., arithmetic logic units, filters, and dedicated state machines). In one embodiment, the controller 48 may be a part an electronic device, such as the console computer system 160, the control tower 13, and / or the user console 12. Although illustratedAtorney Docket No. : AUR6356WOPCT1Electronically Filed as being a single component, the controller may include one or more electronic components (e.g., processors, memory, etc.) that may be communicatively coupled on a single electronic device (such as the console computer system 160), or across multiple devices (e.g., communicating over a wireless computer network). In some embodiments, the controller 48 may be a part of a separate device, such as a part of a remote server that may be in communication with one or more electronic devices of the surgical system 10.

[0062] The controller 48 may be configured to perform one or more operations for controlling and monitoring magnetic brake engagement and disengagement of the joint 21 of the surgical system 10 to determine a (e.g., real-time) status of the magnetic brake. In particular, the controller 48 may be configured to receive user input through the input device 42 to engage or disengage the magnetic brake, which may be based on a current status of the brake (or input device). For example, while the magnetic brake is engaged (e.g., while user input is not received through the input device 42), user input may begin to be received through the device 42. This input may be received through a clutch mechanism (e.g., a button or trigger) of the input device, as described herein. The controller 48 may be configured to control the magnetic brake based on the received user input. In this case, the controller may be configured to provide power to the magnetic brake 32 in order to transition the brake from engagement to disengagement, where the disk 35 may be separated from the brake housing 36.

[0063] The controller 48 may be configured to monitor engagement and / or disengagement. For instance, the controller may be configured to receive one or more characteristics of the magnetic brake. For example, the controller may receive (e.g., a measure of) the input voltage, Vin, and / or the input current, Im. of the (e.g., coil 45 of the) magnetic brake. In one embodiment, Im may be received from a current sensor that may be coupled to the magnetic brake (or between the magnet and the power source). In another embodiment, the characteristics may be received from another electronic device, such as the power source 34 that may indicate the applied voltage, as Vin to the magnetic brake 32. As described herein, the controller 48 may be configured to monitor a status of the magnetic brake based on one or more of the characteristics, such as the measured input current. In particular, the status may be based on whether the input current includes any peaks (e.g., current amplitude that exceeds one or more current thresholds) based on the disengagement or engagement by the controller 48. Returning to the previous example, to disengage theAtorney Docket No. : AUR6356WOPCT1Electronically Filed brake, the controller 48 may apply power to the (internal coil of the) magnetic brake in order for the brake housing to release the disk 35. Upon applying the power, the input current into the magnetic brake may rise (due to the applied voltage). When the brake housing includes a permanent magnet, which may be arranged to attract the disk while the coil is not energized, this applied power to the magnetic brake induces a magnetic field change in the permanent magnet causing the disk 35 to move and eddy currents in the internal coil, which may be sensed as a drop in current. This drop in the current may be a biproduct of the disk moving away from the brake housing. So as the disk moves, the magnetic brake may generate a reverse current flow in the system. In one embodiment, this reverse current may be measured by the controller. For example, a peak detection algorithm executed by the controller may detect a peak in the input current based on the reverse current as a magnitude of input current above a threshold. In one embodiment, a peak may be detected when current may drop (e.g., at a particular rate) and then increases (e.g., at a rate) to reach or exceed a current threshold. Upon detecting the peak, the controller may determine the status of the magnetic brake as being successfully disengaged. As described herein, the status of the magnetic brake may be different based on 1) whether any peaks are measured during engaged / disengaged and 2) whether any peaks that are measured are greater than one or more thresholds.

[0064] In one embodiment, the controller 48 may be configured to determine the status of the magnetic brake based on sensor data from one or more sensors 41. For example, when disengaging the magnetic brake, the controller may determine whether the disk 35 has separated from the brake housing 36 based on sensor data from one or more sensors such as a proximity sensor or an optical sensor, such as a camera. In the case of a proximity sensor, the controller may determine whether the disk has moved and created the gap 37. In particular, the controller may determine whether the gap 37 is greater than a threshold distance between a top surface of the brake housing and a bottom surface of the disk based on the sensor data. If so, this may indicate that the magnetic brake has disengaged, and a notification may be provided indicating that the brake has disengaged. More about the controller determining the status of the magnetic brake based on sensor data is described herein.

[0065] In one embodiment, the controller 48 may provide one or more notifications indicating the status of the magnetic brake. Specifically, upon determining the status, the controller 48 may provide one or more users of the surgical system 10 a notification alerting the users of the status of the brake. For example, the notification may be a visual (pop-up)Atorney Docket No. : AUR6356WOPCT1Electronically Filed notification displayed that may be displayed on a display of the user console 12. As another example, the notification may be an audible alert played back through one or more speakers of the surgical system. In another embodiment, the controller 48 may store the status of the magnetic brake in (e.g., internal) memory. The controller 48 may be configured to control the motor 33 of the joint 21. For instance, upon determining that the magnetic brake has successfully disengaged, the controller may activate the motor 33. More about the controller controlling the motor and the magnetic brake are described herein.

[0066] Figs. 5, 6A, 6B, 8, and 10 are flowcharts of processes 50, 60, 80, and 100, respectively, that each include one or more operations that may be performed by the (e.g., controller 48 of the) surgical system 10 to perform magnetic brake control and monitoring operations, as described herein. Specifically, the operations described herein may be performed during a surgical procedure in which an operator of the surgical system may be using one or more robotic arms (components) with one or more joints with magnetic brakes.

[0067] Turning to Fig. 5, this figure includes a flowchart of one embodiment of a process 50 for determining a status of a magnetic brake of a joint 21 of a robotic arm. As described herein, this process 50 may be performed during a surgical procedure, or may be performed during a simulation of a surgical procedure. The process 50 begins with receiving input indicating that the magnetic brake is to either engage or disengage (at block 51). In particular, the controller 48 may receive user input through the input device 42 to disengage an engaged magnetic brake. The controller 48 determines whether the magnetic brake is to be disengaged based on the received input (at decision block 52). For instance, when the input device includes a clutch mechanism, the determination may be based upon a determination that the input includes a control signal to disengage the magnetic brake. In one embodiment, the determination may be based on a current status of the magnetic brake. Returning to the previous example, the controller 48 may determine that the magnetic brake is to be disengaged since the control signal from the input device is received while the magnetic brake has been engaged. If so, the controller 48 may apply power to the magnetic brake (at block 53). In particular, the controller may cause the power source 34 to supply power to the (coil 45 of the) magnetic brake 32. As another example, the controller may cause the switch 39 (which is open) to close to complete a circuit between the power source and the magnetic brake.Atorney Docket No. : AUR6356WOPCT1Electronically Filed

[0068] The controller 48 determines a status of the magnetic brake (at block 54). Specifically, the controller may be configured to determine the disengagement status of the brake as at least one of 1) a successful disengagement, 2) an unsuccessful disengagement, 3) a slow successful disengagement, or 4) a misaligned successful disengagement. A “successful disengagement” may occur as a result to the applied power, where the disk 35 may separate from the brake housing in one discrete motion. A “misaligned” disengagement, however, may be one in which the disk separates from the housing but does so in two or more motions due to a component misalignment. More about the each of these statuses is described herein. In one embodiment, the status of the magnetic brake may be determined based on one or more measured (or determined) characteristics of the magnetic brake. In particular, the characteristics may be measured responsive to the power being applied to the magnetic brake. More about the characteristics is described herein. The controller 48 determines whether the magnetic brake has disengaged (at decision block 55). In this case, the controller may determine whether the determined status of the magnetic brake may be an unsuccessful disengagement. In one embodiment, an “unsuccessful disengagement” may be when power applied to the coil 45 may not result in the disk 35 retracting away from the brake housing 36. As another example, disengagement of the disk may be unsuccessful when the gap 37 between the disk 35 and the brake housing 36 is within (or smaller than) a threshold distance, which may be determined based on sensor data captured by the one or more sensors 41.

[0069] If the magnetic brake has disengaged, the controller 48 may activate the motor to move the robotic arm (at block 57). In particular, the controller 48 may activate the motor responsive to determining that the status of the brake indicates that the brake has disengaged. Once disengaged, the controller may be configured to provide a control signal to the motor 33 to move or rotate the shaft 38, as described in Fig. 3. Thus, the control signal may cause the motor to move at least a portion (e.g., one or more links) of the robotic arm 14. The controller may provide a notification indicating the status of the magnetic brake (at block 56). In one embodiment, the notification may indicate at least one of the status of the magnetic brake, such as being a successful disengagement, an indication that the motor has moved, and / or an amount of movement of the motor (or the robotic arm). If, however, the magnetic brake has not disengaged (e.g., having a status of unsuccessful disengagement), the controller 48 may provide a notification indicating the status of the magnetic brake (at block 56). Specifically, the controller may output a notification indicating that the magnetic brake has not beenAtorney Docket No. : AUR6356WOPCT1Electronically Filed disengaged. In one embodiment, since the magnetic brake 32 has not been disengaged, the controller 48 may hold or prevent power to the motor 33.

[0070] Returning to the decision block 52, when the magnetic brake is to be engaged, the controller 48 ceases to apply power to the magnetic brake (at block 58). As an example, the power being applied to the magnetic brake 32 may be stopped by opening the switch 39. The controller 48 determines the status of the magnetic brake at block 54. In particular, the controller may be configured to determine the engagement status of the brake as at least one of 1) a successful engagement, 2) an unsuccessful engagement, 3) a slow successful engagement, or 4) a misaligned successful engagement. As described herein, the engagement status of the brake may be determined based on one or more characteristics of the brake. More about determining the engagement status is described herein. The controller 48 may be configured to determine whether the magnetic brake has (e.g., successfully) engaged (at decision block 98). For example, the controller may determine whether the magnetic brake has successfully engaged based on whether a measured input current and / or sensor data. For instance, the controller may determine whether engagement is successful based on whether the input current includes one or more peaks, or whether sensor data from one or more sensors indicates that there is no longer a gap 37 between the disk 35 and the housing 36 (or that the gap is smaller than a threshold distance). If not, the controller may be configured to apply power back to the magnetic brake (at block 53) and perform one or more of the operations of process 50 to determine whether the brake has engaged after power has been applied again. In other words, the system 10 may cycle power through the magnetic brake to see if the brake may engage. As described herein, the system may cycle the brake a number of times, and if it continues to not engage successfully, the system may provide a notification. If, however, the brake is engaged, the controller 48 deactivates the motor (at block 59). In particular, since the controller is engaging or attempting to engage the magnetic brake 32, the controller 48 may deactivate or put on hold the motor in order to not run the motor while the brake is engaged. In one embodiment, the controller 48 may deactivate the motor before engaging the brake. The controller provides a notification based on the engagement status and / or based on the deactivation of the motor at block 56.

[0071] Figs. 6A and 6B is a flowchart of one embodiment of a process 60 for disengaging the magnetic brake 32 of the joint 21. In one embodiment, the process 60 of these figures may include one or more operations that may be performed over one or moreAtorney Docket No. : AUR6356WOPCT1Electronically Filed operational blocks 53-57 of Fig. 5 when controlling and monitoring the disengagement of the magnetic brake 32. As shown, the process 60 may include one or more operational blocks of process 50 in Fig. 5. As a result, these blocks may not be described with respect to process 60 for the sake of brevity.

[0072] The process 60 begins with the application of power to the magnetic brake (at block 53). As described herein, the power may be applied responsive to the controller 48 receiving user input via the input device 42. The controller 48 determines one or more characteristics of the magnetic brake (at block 61). Characteristics may include a measured input voltage and / or a measured input current into the coil 45 of the magnetic brake 32. In another embodiment, the characteristics may be based on sensor data captured from one or more sensors 41. The characteristics may be physical characteristics determined based on the sensor data. For example, a characteristic may include a distance of the gap 37 between the disk 35 and the brake housing 36, which may be measured using a proximity sensor and / or an optical sensor.

[0073] To disengage the magnetic brake, the provision of current to the coil 45 may result in heating, which may cause an increase in coil resistance. In particular, the temperature of magnetic brake may increase the longer the magnetic brake 32 is disengaged due to the current being applied to the coil over a period of time. As the coil resistance increases, the temperature of the magnetic brake 32 may increase. If the temperature gets too high, the magnetic brake may fail due to overheating. Therefore, the controller may estimate a temperature of the magnetic brake based on at least one characteristic (at block 62). In particular, the controller 48 may estimate the temperature based on the measured input current and the input voltage. For example, the controller may estimate the resistance of the coil 45 of the magnetic brake 32 based on the current and voltage according to Ohm’s law (e.g., R = y) and may determine the temperature based on the resistance. In one embodiment, the controller 48 may perform a table lookup into a data structure that associates resistances with temperature. The controller determines whether the temperature of the magnetic brake is greater than a temperature threshold (at decision block 63). If so, the controller 48 may engage the magnetic brake by removing or reducing the applied power (at block 64). Specifically, the controller 48 may lock the magnetic brake in place, cease providing powerAtorney Docket No. : AUR6356WOPCT1Electronically Filed to the brake, and / or put the associated joint in a hold position as a result of a detection of excessive temperature.

[0074] In one embodiment, the controller 48 may actively monitor the characteristics of the magnetic brake, such as the input voltage and current levels, thereby allowing the controller to continuously compute and monitor the coil resistance for temperature estimation (e.g., in real-time as the magnetic brake is disengaged). By estimating the temperature during prolonged disengagement, the system 10 may prevent overheating-related issues with the magnetic brake by engaging the brake if it gets too hot. This preventative measure ensures the durability and reliability of the magnetic brake 32, especially during extended disengagement periods.

[0075] If, however, the temperature is not greater than the temperature threshold, the controller 48 determines whether the measured input current of the magnetic brake has any peaks (at decision block 93). As described herein, as current is applied to the magnetic brake for disengagement, a magnetic field change is induced by the coil 45 to cause motion of the disk 35 to disengage from the brake housing 36 and causes eddy currents that appear as one or more drops in the input current (e.g., over a period of time). After the drop(s), the current may continue to rise (e.g., to a maximum current value). The drop(s) may form one or more peaks and / or one or more troughs of the input current, and are therefore a biproduct of the disk moving away from the brake housing 36. In one embodiment, to determine whether the current has one or more peaks, the controller 48 may be configured to perform a peak detection algorithm that may monitor the input current and / or the rate of change (e.g., the first derivative) of current and use that information to identify changes that are indicative of peaks in measured current. In one embodiment, a peak in current may be a sharp decrease (or increase) in current over a short period of time, where the sharp decrease (or increase) may be greater than a (e.g., amplitude) threshold. In another embodiment, the peak detection algorithm may detect peaks based on a determination of whether the rate of change of measured current is greater than a threshold change. If so, this may indicate that the current includes a current peak. As described herein, the rate of change may vary due to eddy currents that are the result of the disk separating (moving away) from the brake housing 36. In one embodiment, the controller 48 may determine a current function based on the input current and determine the first derivative of the function, and determine whether one or more peaks exist based on the derivative being greater than a threshold.Atorney Docket No. : AUR6356WOPCT1Electronically Filed

[0076] As a result, if no peaks are detected (e.g., within a time period after power is applied), this may be indicative of an unsuccessful disengagement. In which case, the controller may determine whether a number of reattempts to disengage the magnetic brake exceed a threshold (at decision block 65). If not, the controller 48 may cease applying power to the magnetic brake (at block 58), and may return to block 53 in Fig. 6A. As a result, the controller 48 may be configured to cycle the applied power to the magnetic brake to determine whether disengagement of the magnetic brake 32 may ultimately become successful. In one embodiment, the number of reattempts may be predefined. If, however, the controller 48 returns to decision block 65 after the number of attempts, such as three attempts, to disengage the magnetic brake by cycling the applied power on and off, the controller may determine the status of the magnetic brake as an unsuccessful (or failed) disengagement (at block 66). As a result of continuing to reattempt disengagement, this serves as a safeguard to prevent excessive wear on the brake components. By promptly identifying disengagement issues and refraining from initiating or activating the motor 33 movement, the system 10 avoids unnecessary strain on the brake. This approach involves cycling the current (power) to the brake before attempting motor movement, thereby allowing for repeated disengagement attempts without imposing undue stress on the brake mechanism, which would otherwise by applied if the motor were allowed to move. This method provides a measured response to ensure the durability of the brake, contributing to the long-term reliability of the system 10. The controller 48 may provide a notification indicating the status of the magnetic brake (at block 56). In this case, the notification may indicate that the brake as an unsuccessful disengagement status. In particular, the magnetic brake may be stuck in a locked (engaged) position, thereby locking the joint 21 in place.

[0077] Returning to decision block 93, if the input current includes one or more peaks, the controller 48 may be configured to determine whether the input current has multiple, two or more, peaks (at decision block 67). For instance, the controller may determine whether the rate of change in current exceeds a threshold, such as zero, two or more times over a period of time, as power is applied to the magnetic brake. In one embodiment, this period of time may be a time period that it takes for the disk 35 to successfully separate from the brake housing 36. If so, the controller 48 may be configured to determine a status of the magnetic brake as a misaligned successful disengagement (at block 68). In particular, the controller 48 determines that although the disengagement between theAtorney Docket No. : AUR6356WOPCT1Electronically Filed disk 35 and the brake housing 36 is successful, one or more components of the magnetic brake may not aligned (e.g., within a threshold alignment). For example, as shown in Fig. 3, the disk 35 and the brake housing 36 may be aligned with one another such that a bottom surface of the disk 35 and a top surface of the magnetic brake 32 are parallel with one another (e.g., are rotatably aligned along an orthogonal axis with respect to the Z-axis). This alignment may cause the entire bottom surface of the disk 35 that is in contact with the top surface of the magnetic brake 32 to separate at once during disengagement. In other words, when both components are aligned (e.g., within a threshold) to one another, a successful, aligned, disengagement would result in separation in a single discrete motion.

[0078] If, however, one component is misaligned along at least one axis (e.g., with respect to the brake housing), such as the disk 35 not being rotatably aligned with the magnetic brake 32 along the orthogonal axis with respect to the Z-axis, different portions of the disk may separate from the permanent magnet at different times during disengagement. Specifically, instead of separating through a single discrete step, separation between the components may take two or more discrete steps or motions. For example, bottom surface of the disk 35 may include a first portion (e.g., to the right of the Z-axis) and a second portion (e.g., to the left of the Z-axis). Due to the misalignment, when power is applied to the coil 45, the first portion may separate from the permanent magnet before the second portion separates from the permanent magnet. In one embodiment, misalignment may be due to wear and tear of the magnetic brake. The controller 48 activates the motor (at block 57), and provides a notification indicating the status of the magnetic brake (at block 56). In this case, the controller 48 may alert a user of the surgical system that the magnetic brake is misaligned, and that maintenance of the magnetic brake may be required. As a result, the system may be able to disengage the brake and perform a joint movement, while also alerting the user that maintenance may be necessary.

[0079] Returning to decision block 67, if the input current only has one peak, the controller 48 determines whether the single peak’s amplitude is greater than a threshold (at decision block 69). In particular, the controller 48 may determine whether one peak has a magnitude that is greater than a threshold. In one embodiment, the controller 48 may measure the amplitude of the between a high point (e.g., peak) and a low point (e.g., a trough) measured within the input current. In one embodiment, this threshold may be different (e.g., greater) than an amplitude threshold that the peak detection algorithm may use to determineAtorney Docket No. : AUR6356WOPCT1Electronically Filed whether the input current includes one or more peaks. In another embodiment, the controller may determine the amplitude based on a rate of change of the input current based on the disengagement of the magnetic brake. More about determining the amplitude is described herein. If the single peak’s amplitude is greater than the threshold, the controller determines the status of the magnetic brake as being successfully disengaged (at block 92). In particular, this successful disengagement status may indicate a disengagement where the disk 35 may be separated from the brake housing 36 in a single discrete motion that is less than a time threshold to disengage and as expected with respect to the applied voltage. This may be in contrast to a misaligned successful disengagement in which the disk becomes disengaged from the permanent magnet over two or more motions, as described herein. This successful disengagement may be within a minimum deviation of an expected disengagement, which may be determined in a controlled environment (e.g., in a laboratory). The controller 48 may be configured to activate the motor (at block 57) and provide a notification of the status of the brake (at block 56). As a result, responsive to a determination that the input current of the coil includes one peak, the status of the magnetic brake may be disengaged such that the disk is no longer in contact with the brake housing.

[0080] Returning to decision block 69, if the single peak’s amplitude is not greater than the threshold, the controller determines a status of the magnetic brake as being a slow successful disengagement (at block 91). In one embodiment, a “slow” successful disengagement may be a disengagement in which the disk 35 may not separate from the brake housing 36 as expected. In particular, the status may indicate that the brake performed a single discrete movement longer than the time threshold (indicated with respect to block 92) to disengage. In one embodiment, this slow disengagement may be the result of one or more objects, which may be between the disk and brake housing that may be adding resistance to the separation of the disk and the magnet. This resistance may cause the disk to separate from the brake housing over a threshold period of time. In contrast, the successful disengagement identified in block 92 may be a disengagement in which the disk separates from the disk housing within (or less than) the threshold period of time. In one embodiment, this may be indicative of one or more objects (e.g., dust) being between the disk and the magnet (e.g., between a lower surface of the disk and an upper surface of the magnet). In another embodiment, a slow successful disengagement may be an indication of another issue, such as a potential onset of misalignment between the disk 35 and the brake housing 36. TheAtorney Docket No. : AUR6356WOPCT1Electronically Filed controller 48 may activate the motor (at block 57) and provide a notification (at block 56). In one embodiment, the notification may indicate that maintenance may be required upon the magnetic brake 32 of the joint 21.

[0081] Figs. 7A - 7D show several curves (or graphs) 70-77 of characteristics of the joint magnetic brake that indicate the brake’s disengagement status according to one embodiment of the disclosure. In particular, curves 70, 72, 74, and 76 show measured input current (e.g., in milliamperes (mA)) into the (e.g., coil 45 of the) magnetic brake 32 with respect to time, and curves 71, 73, 75, and 77 show the rate of change (RoC) of the input current of curves 70, 72, 74, and 76, respectively, e.g., in milliampere s / seconds (mA / s), with respect to time. In particular, curves 70, 72, 74, and 76 show how current is applied over time, where the current reaches a maximum applied current after a period of time in which power is applied to the magnetic brake.

[0082] Turning to Fig. 7A, this figure shows the measured input current and the RoC of the input current for a successful disengagement of the magnetic brake 32. Curve 70 shows a peak 94 in the input current, while curve 71 shows a RoC that corresponds to the peak 94. As described herein, this peak 94 may be the result of a reverse current produced in response to the disk 35 separating from the brake housing 36. In one embodiment, the controller 48 may be configured to determine a successful disengagement status based on an amplitude of the peak 94, with respect to the following trough in the curve 70, where the amplitude may be above a threshold.

[0083] Fig. 7B shows the measured input current and rate of change of the input current for a slow successful disengagement of the magnetic brake 32. Curve 72 shows a peak 95 in the input current, while curve 73 shows a corresponding RoC. In one embodiment, the controller 48 may determine this to be a slow successful disengagement, since an amplitude of the peak 95 may be less than a threshold amplitude (e.g., between the peak and the following trough in the curve 72), whereas an amplitude of peak 94 may be greater.

[0084] Fig. 7C shows the measured input current and the rate of change for a misaligned successful disengagement. In particular, the curve 74 includes two peaks, 96 and 97. In one embodiment, this type of disengagement may include two or more peaks, where each peak may have an amplitude that is greater than a minimum threshold. In another embodiment, the controller may determine the status of the magnetic brake as being aAtorney Docket No. : AUR6356WOPCT1Electronically Filed misaligned successful disengagement, where two or more peaks are detected within a threshold period of time. Conversely to the three previous figures, Fig. 7D shows the input current of the magnetic brake when disengagement fails. In particular, curve 76 shows that the input current does not include a peak, and curve 77 does not have a corresponding rate of change.

[0085] As described herein, the status of the magnetic brake may be determined based on whether one or more peaks are present and their corresponding amplitude. In another embodiment, the status of the magnetic brake may be based on whether there is a negative RoC, which corresponds to a peak in the input current. In this case, the controller 48 may be configured to determine that disengagement has failed, since curve 77 does not include a negative RoC, below zero.

[0086] Disengagement of a magnetic brake may involve applying a fixed maximum voltage. This may lead to a large current draw (e.g., a high threshold current) by the magnetic brake from the power source. In fact, the movement (or actuation) of the disk 35 and therefore the disengagement of the magnetic brake occurs before the current reaches the high threshold current. As a result of this unnecessarily excess high current (e.g., the additional current between the current required for disengagement and the high threshold current) the magnetic brake may overheat, especially when the brake needs to be held disengaged for an extended duration of time. Operating the brake with maximum voltage input for prolonged time has a risk of permanently damaging the brake and therefore the joint. In the absence of a temperature sensor on the brake, may mean there is no way to detect or address overheating problems promptly. Therefore, there is a need for real-time sensing of disengagement, controlling, and limiting the brake current input to an appropriate level.

[0087] The present disclosure provides a method and system for controlling and limiting brake current input in order to prevent (or reduce) overheating while also allowing for prolonged disengagement of the magnetic brake. In particular, to control and limit brake current input, the present disclosure maintains a minimum necessary applied current for (e.g., prolonged) disengagement. Fig. 8 is a flowchart of one embodiment of a process 80 for maintaining a minimum necessary applied current for disengaging the joint magnetic brake. The process 80 begins with the controller 48 increasing the power applied to the magnetic brake (at block 81). For example, this increase in power may be applied as a result ofAtorney Docket No. : AUR6356WOPCT1Electronically Filed receiving user input via the input device 42. In particular, this increase in power may be an initial increase, such as at or above a minimum threshold, below which the magnetic brake may be engaged. As an example, this minimum threshold may be associated with a starting input current at an initial voltage. In which case, the controller 48 may apply (e.g., an initial) power to the magnetic brake of a robotic component.

[0088] The controller 48 determines whether the magnetic brake has (e.g., successfully) disengaged responsive to the applied power (at block 82). In particular, the controller 48 may determine that the magnetic brake has disengaged based on the peak detection algorithm detecting one or more peaks within the input current, as described herein. If a successful disengagement is not detected, the controller may determine whether the duration to disengage the magnetic brake has met or exceeded a (time) threshold (at decision block 83). In particular, the controller may determine whether power has been applied to the magnetic brake for an extended period of time. In one embodiment, applying (e.g., excessive) power for an extended period of time may cause the brake to overheat. If not, the controller determines whether the (applied) current to disengage the magnetic brake meets or exceeds a threshold (at decision block 84). Specifically, the controller determines whether the current that is being applied due to the previous increase in applied power exceeds a current threshold. In one embodiment, this threshold may be the maximum amount of input current that may be applied to the magnetic brake (e.g., based on a manufacturer specification). If not, the controller may proceed back to block 81 to increase the applied power. In one embodiment, the controller may increase power (e.g., the input current) by a predetermined step value. In one embodiment, the controller may apply power by incrementally increasing the power applied to the magnetic brake until it is determined that the magnetic brake has successfully disengaged, a threshold duration has been met, and / or the applied current has reached a threshold.

[0089] If this increase in power successfully disengages the magnetic brake, the controller 48 may determine the input current at which the magnetic brake disengaged based on the applied power (at block 85). Specifically, the controller may identify the peak(s) of input current that are indicative of the disk 35 separating from the housing 36. As another example, referring to Fig. 7C, the controller may determine the current level at peak 97 of the curve 74. In one embodiment, when there are multiple peaks, the controller 48 may determine the input current level associated with the last peak. The controller 48 may be configured toAtorney Docket No. : AUR6356WOPCT1Electronically Filed adjust (or maintain) the applied power to the magnetic brake based on the input current (at block 86). In particular, the controller 48 may perform an adjustment to the power supplied to the coil of the magnetic brake, while the magnetic brake remains disengaged. For example, the controller 48 may reduce the applied power based on (e.g., to correspond to) the determined input current. This may be the case when the last increase of applied power was greater than necessary for disengaging the magnetic brake. In particular, with the input current determined, which may be the minimum necessary current to (successfully) disengage the brake, the controller 48 may adjust the input voltage applied to the magnetic brake so as to provide the brake with the necessary current. In one embodiment, the necessary current may be a current value based on a (e.g., last) detected peak of input current. Specifically, the controller 48 may set the current to a highest current value associated with the peak. In another embodiment, the controller 48 may adjust the applied power such that the current provided to the magnetic brake is greater than the current of the identified peak by a threshold (e.g., percentage value). Thus, the controller may adjust the applied power by reducing the power based on a difference between the (e.g., last) peak of the input current and the initial (e.g., currently applied) current to the (e.g., coil of the) brake. As an example, the controller may increase the power by increasing the applied current to the coil, and when disengagement is detected, the controller may adjust the current (if necessary), where the adjustment may be based on a difference between a detected peak in the input current and the applied current to the coil. In one embodiment, the controller 48 may adjust the voltage due to a known (e.g., determined in a controlled setting, such as a laboratory, or based on a manufacturer’s specification) resistance of the coil 45 of the magnetic brake 32 and the desired current. Thus, the voltage may be reduced based on the desired input current and the resistance of the coil.

[0090] The controller may provide a notification indicating the status of the magnetic brake (at block 56). For instance, the controller may provide a notification indicating the input current necessary for disengagement of the brake and indicating that the brake has been successfully disengaged.

[0091] If, however, the magnetic brake has not been successfully disengaged (at decision block 82) and the duration has not exceeded the threshold (at decision block 83), the controller may determine that the current to disengage the magnetic brake exceeds the threshold at decision block 84. In particular, in an attempt to find an input current that willAtorney Docket No. : AUR6356WOPCT1Electronically Filed disengage the magnetic brake, the controller 48 may have applied an input current at or above a maximum threshold. For example, the controller may cycle through blocks 81-84, increasing the current until the applied current meets or exceeds a current threshold. If so, instead of increasing the applied power, the controller may maintain the last applied current, e.g., returning to decision block 83 in response to determining that the magnetic brake has not successfully disengaged at decision block 82, to determine whether the duration has met or exceeded the duration threshold. If so, meaning that the amount of time in which current has been applied to the magnetic brake has reached a maximum threshold, the controller may proceed to cease applying power (at block 58), in order to prevent the brake from overheating.

[0092] In one embodiment, the surgical system 10 may maintain the applied power (e.g., an applied input voltage that results in the determined input current drawn by the magnetic brake) for a remainder of the disengagement of the magnetic brake. In some embodiments, the system 10 may perform at least some of these operations each time the brake is disengaged. For example, the operations may be performed before (or after) the activation of the motor 33 at block 57 in process 60 of Fig. 6B.

[0093] As a result, the surgical system may keep the magnetic brake current input fixed at the “minimum necessary” level based on the detection of disengagement. As described herein, this minimum necessary level provides a slower rise in the brake temperature, and therefore may prevent overheating in the case of prolonged disengagement of the brake.

[0094] Fig. 9 shows several curves illustrating comparisons of characteristics of the joint magnetic brake when the minimum necessary applied current is applied to the joint magnetic brake and when a maximum voltage is applied to the joint magnetic brake to disengage the brake. In particular, this figure shows the current, voltage, and temperature of the magnetic brake during disengagement with respect to time. Curves 150a, 151a, and 152a show these characteristics of the brake when a maximum threshold voltage are applied to the magnetic brake in order to disengage the brake over a period of time, whereas curves 150b, 151b, and 152b show corresponding characteristics when the input current is limited, as described in Fig. 8. Thus, reducing the applied voltage (e.g., below the maximum thresholdAtorney Docket No. : AUR6356WOPCT1Electronically Filed voltage, such as 24 volts (v)), as shown in curve 151b, the input current and therefore the temperature on the magnetic brake may also be reduced.

[0095] As described thus far, the surgical system 10 may perform control and monitoring operations of the disengagement of the magnetic brake 32 of the joint 21. In another embodiment, the system may perform at least some of these operations to control and monitor engagement of the magnetic brake. Fig. 10 is a flowchart of one embodiment of a process 100 for engaging the magnetic brake of the joint of the robotic arm. In one embodiment, the process 100 may include one or more operations that may be performed over one or more operational blocks 58, 54, 59, and / or 56 of Fig. 5 when controlling and monitoring the engagement of the magnetic brake 32. As shown, the process 100 may include one or more operational blocks of processes 50 and 60 in Figs. 5, 6A, and 6B, respectively. As a result, these blocks may not be described with respect to process 100 for the sake of brevity.

[0096] In one embodiment, at least some of these operations may be performed responsive to user input from the input device to engage one or more joints. For example, the controller 48 may disengage the brake by applying power, thereby allowing a joint to move a robotic arm, and may provide a control signal to a motor of the joint to move the robotic arm, based on user input. Once a movement is complete, the controller 48 may receive (e.g., another) user input indicating that the joint is to lock in place. For example, the controller may sense that the user has released a clutch mechanism. In another embodiment, the system may automatically (e.g., without user intervention) determine that a joint is to lock after a movement. For example, the system may receive user input to rotate a joint 30°. In response, the system may disengage the joint, rotate the appropriate amount, and engage the joint.

[0097] Turning to Fig. 10, the process 100 begins with the controller 48 putting the motor into a position holding mode (at block 101). In particular, the controller may cause the motor 33 of the brake’s joint to hold (or lock) its current position, while the controller determines (or attempts) to engage the magnetic brake of the joint. Referring to Fig. 3, putting the motor 33 in a holding mode may cause the motor to keep the shaft 38 at its current orientation. Thus, this mode may prevent the robotic arm from moving, while the controller 48 determines (or attempts) to engage the brake. In one embodiment, the controller 48 may keep the motor 33 in an active closed loop control to maintain its last measured position. InAtorney Docket No. : AUR6356WOPCT1Electronically Filed some embodiments, the motor may be put into the position holding mode, responsive to receiving input (e.g., via an input device) indicating that the magnetic brake is to transition from being disengaged to engaged. For instance, the input may be an indication that a clutch mechanism of the input device has been released. The controller 48 ceases to apply power to the magnetic brake (at block 58). Specifically, the controller may cease to apply power to the magnetic brake to transition the brake form being disengaged to engaged. The controller 48 measures one or more characteristics of the magnetic brake (at block 61), such as the input current. For instance, the controller may measure the input current as a function of time (e.g., over a period of time from when the controller ceases to apply the power). The controller 48 determines whether the input current includes any peaks (at decision block 93). Since power to the coil 45 has been deactivated, an input current level of the magnetic brake will decrease. As a result, the magnetic field produced by the coil 45 may be reduced (or eliminated), and in response the disk 35 may be attracted or pushed towards the brake housing 36. As described herein, the disk 35 may be attracted to the housing via a permanent magnet, or it may be mechanically pulled (or pushed) towards the housing by one or more springs, for example. As the disk 35 moves towards the magnetic brake, it may induce current through the coil 45 due to electromagnetic induction. This increase in current may cause one or more peaks in the input current, which will eventually drop off. As described herein, a peak detection algorithm may monitor the input current to determine whether the input current includes a sharp increase or change (over a period of time). For example, the detection algorithm may determine whether a rate of change of the input current exceeds a threshold and / or whether an amplitude of the input current exceeds a threshold over a period of time.

[0098] As described herein, if the input current does not have any peaks (or any peaks above a threshold), this may indicate that the magnetic brake has not engaged in response to no longer applying power. The controller 48 determines whether a number of reattempts to engage the magnetic brake exceeds a threshold (at decision block 102). If not, the controller 48 may cycle the magnetic brake. In which case, the controller 48 may apply the power to the magnetic brake to disengage the brake (at block 53). The controller 48 may then repeat at least some of these operations to cycle the magnetic brake if the input current is found to not include any peaks. The controller 48 may cycle between turning the power on and off for at least a period of time, which may be based on the number of attempts. Once the number of reattempts (e.g., three attempts) to engage the magnetic brake exceeds the threshold, theAtorney Docket No. : AUR6356WOPCT1Electronically Filed controller 48 may be configured to determine a status of the magnetic brake as an unsuccessful engagement (at block 103), and may provide a notification indicating the status (at block 56). In one embodiment, an “unsuccessful engagement” may occur when the disk 35 does not come into complete (or only comes into partial) contact with the brake housing, thereby not providing sufficient frictional resistance that would prevent the shaft 38 from rotating. In particular, the controller 48 may provide a notification indicating that the status of the brake as an unsuccessful engagement, and may maintain the motor in the position holding mode. Thus, the controller may iteratively apply power and cease applying the power to the brake to determine whether the status of the brake changes from being disengaged to being engaged. At each iteration, the controller may determine whether the number of iterations has exceeded the threshold, and in response to exceeding the threshold, the notification may be provided that the status of the brake is unsuccessful engagement. As a result, even though the brake may not be engaged, the motor may remain in the position holding mode to prevent the robotic arm from moving.

[0099] When attempting to lock the joint 21 by engaging the brake 32, the identification of a failed engagement may be instrumental in preventing unintended sliding movement of the joint. As described herein, upon not identifying any peaks, the system 10 may direct the motor to hold its position, preventing any undesired shifting. In one embodiment, the current input to the brake may be cycled on / off, providing repeated attempts until successful engagement is detected (or until a threshold is reached). This approach ensures that the joint remains securely locked, mitigating the risk of unintended movements and enhancing the stability of the robotic system.

[0100] If, however, the input current includes at least one peak, the controller 48 determines whether the input current has multiple peaks (at decision block 67). If so, the controller 48 determines a status of the magnetic brake as a misaligned successful engagement (at block 104). Similar to a misaligned successful disengagement, as the disk 35 comes into contact with the permanent magnet, it may take two or more motions, rather than a single (e.g., downward) motion. In which case, a first portion of the disk 35 may come into contact with the magnet before a second portion of the disk comes into contact. The controller 48 deactivates the motor (at block 59) and provides a notification that the magnetic brake 32 is a misaligned successful engagement (at block 56).Atorney Docket No. : AUR6356WOPCT1Electronically Filed

[0101] If, however, the input current only includes one peak, the controller determines whether the single peak’s amplitude is greater than a threshold (at decision block 69). In one embodiment, this threshold may be the same threshold used by the controller 48 in process 60. If so, the controller determines a status of the magnetic brake as a successful engagement (at bock 106). In one embodiment, a “successful engagement” may indicate that once power is taken away, the disk 35 may come into contact with the brake housing 36 in a single (downward) discrete motion. If, however, the single peak’s amplitude is not greater than the threshold, the controller 48 determines the status of the magnetic brake as a slow successful engagement (at block 105). Similar to a slow disengagement, a slow engagement may occur when the break engages, but over a longer threshold of time than just a successful engagement. A slow engagement may be indicative of resistance on the magnetic brake, which may be due to contamination in the gap 37 and / or misalignment between the disk and the magnet.

[0102] Fig. 11A - 11D show several curves 110-117 of characteristics of the joint magnetic brake that indicate the brake’s engagement status according to one embodiment of the disclosure. In particular, curves 110, 112, 114, and 116 show measured input current into the coil 45 of the brake 32 with respect to time, and curves 111, 113, 115, and 117 show the RoC of the input current of curves 110, 112, 114, and 116, respectively, with respect to time. Turning to Fig. 11 A, this figure shows the measured input current and the RoC of the input current for a successful engagement of the magnetic brake 32. In particular, the curve 110 shows a peak 169 in the input current, while the curve 111 shows the rate of change that corresponds to the peak 169. As described herein, the controller 48 may determine that this engagement is a “successful” engagement, where the disk 35 has a single motion to come into contact with the magnet based on the peak 169. For instance, the controller 48 may determine that there is a rate of change that is greater than a threshold, and in response determine whether an amplitude of an associated peak 169, such as a difference between a lowest input current before the rate of change and a highest input current of the rate of change is greater than (or equal to) a threshold. If so, the controller 48 may determine that the magnetic brake has successfully engaged. In another embodiment, the controller may determine that there is a (e.g., slow, and / or misaligned) successful engagement based on whether the RoC exceeds a threshold, such as zero.Atorney Docket No. : AUR6356WOPCT1Electronically Filed

[0103] Fig. 11B shows a curve 112 for the measured input current and a curve 113 of the RoC of the input current for a slow successful engagement of the magnetic brake 32. In this case, the controller may determine that there is a successful engagement (e.g., due to the RoC being greater than zero), but because the amplitude of the peak 161 is less than a threshold (and / or greater than another threshold), the status is a slow engagement, where the disk 35 comes into contact with the brake housing 36 in a single motion, but slower than a threshold speed.

[0104] Fig. 11C shows the measured input current and RoC for a misaligned successful engagement. Specifically, the curve 114 includes two peaks, 162 and 163. In one embodiment, the controller may determine that the engagement of the magnetic brake 32 is misaligned by determining that the curve 114 includes at least two peaks with amplitudes that are greater than or equal to a threshold, as described herein. Conversely to the three previous figures, Fig. 11D shows the input current and the RoC when there is an unsuccessful engagement in which the magnetic brake fails to engage. The curve 116 shows that the input current does not include a peak, and curve 117 does not have any significant changes, such as a RoC that exceeds zero.

[0105] In one embodiment, the system 10 may perform at least some of the operations of at least some of the processes described herein in real-time during a (teleoperation) surgical procedure. In which case, the system may perform the process(es) to continuously monitor one or more magnetic brake’s operational health by detecting and analyzing (e.g., peaks of) input current during the use of the surgical system. A single, sharp, change in the input current of the magnetic brake may signify a successful disengagement (and engagement) process of the brake. Multiple peaks, however, may be indicative of positional alignment issues between internal joint components, such as disks and magnets. Multiple peaks may be the result of a magnetic disk taking multiple discrete steps to engage / disengage, rather than a single-step motion to separate from (or come in contact with) the permanent magnet. Additionally, a decrease in peak sharpness (e.g., having an amplitude below a threshold) may indicate a slower engagement / disengagement process, pointing to possible mechanical resistance on the magnetic disk or contamination in the brake space. This monitoring capability enables proactive maintenance by technicians of the system and early issue detection, contributing to the overall reliability and performance of the brake system.Atorney Docket No. : AUR6356WOPCT1Electronically Filed

[0106] As described herein, the system 10 may determine one or more characteristics of the magnetic brake 32 to determine the status of the magnetic brake. These characteristics may include physical attributes of one or more components of the brake that may be detected through sensor data captured by one or more sensor 41. For example, the controller 48 may determine whether the magnetic brake has successfully engaged (or disengaged) based on image data captured by one or more cameras. Specifically, once instruction from the input device 42 is received to engage the brake, the controller may de-energize the coil 45 and may receive one or more images captured by a camera. The controller 48 may analyze the images to determine whether the disk has come into contact with the brake housing 36. In one embodiment, the controller may use the images to determine how many discrete steps it takes for the disk to come into contact with the magnet. In which case, the controller may determine the status of the brake based on the number of discrete steps. In another embodiment, the controller may use sensor data and other characteristics, such as input current, to determine the status of the brake.

[0107] In another embodiment, the controller may determine other characteristics based on one or more other sensors 41. For example, when the sensors include an optical sensor, which may include diodes (e.g., light emitting and / or light sensitive diodes), the controller may determine the status of the break based on optical sensor data. In another embodiment, the sensor may be a proximity or contact sensor, which may indicate the position of the disk 35 with respect to the brake housing 36.

[0108] In some embodiments, the magnetic brake includes a permanent magnet and a ferromagnetic plate, where the provided notification includes, responsive to the status of the brake indicating a slow successful disengagement, an indication of at least one of an object between the permanent magnet and the ferromagnetic plate and a misalignment between the ferromagnetic plate and the permanent magnet along one or more axes.

[0109] Some embodiments may perform variations to at least some of the processes described herein. For example, the specific operations of at least some of the processes may not be performed in the exact order shown and described. The specific operations may not be performed in one continuous series of operations and different specific operations may be performed in different embodiments. For example, the operations within dashed boxes may be optional operations that may not be performed while (or each time) a respective process isAtorney Docket No. : AUR6356WOPCT1Electronically Filed performed. In another embodiment, one or more operations that have solid boundary boxes may be optional. In one embodiment, at least some of the operations described herein (e.g., performed in one or more processes described herein) may be performed automatically (e.g., without user interference). For example, at least some operations may be performed at any stage during a surgical procedure. In some embodiments, at least some of the operations described herein may be performed (e.g., continuously) in real-time (e.g., while a robotic arm is in use).

[0110] As previously explained, an embodiment of the disclosure may be a non- transitory machine -readable medium (such as microelectronic memory) having stored thereon instructions, which program one or more data processing components (generically referred to here as a “processor”) to (automatically) perform controlling and monitoring operations for engagement and disengagement of a magnetic brake, as described herein. In other embodiments, some of these operations might be performed by specific hardware components that contain hardwired logic. Those operations might alternatively be performed by any combination of programmed data processing components and fixed hardwired circuit components.

[0111] To aid the Patent Office and any readers of any patent issued on this application in interpreting the claims appended hereto, applicants wish to note that they do not intend any of the appended claims or claim elements to invoke 35 U.S.C. 112(f) unless the words “means for” or “step for” are explicitly used in the particular claim.

[0112] While certain embodiments have been described and shown in the accompanying drawings, it is to be understood that such embodiments are merely illustrative of and not restrictive on the broad disclosure, and that the disclosure is not limited to the specific constructions and arrangements shown and described, since various other modifications may occur to those of ordinary skill in the art. The description is thus to be regarded as illustrative instead of limiting.

[0113] In some embodiments, this disclosure may include the language, for example, “at least one of [element A] and [element B].” This language may refer to one or more of the elements. For example, “at least one of A and B” may refer to “A,” “B,” or “A and B.” Specifically, “at least one of A and B” may refer to “at least one of A and at least one of B,” or “at least of either A or B.” In some embodiments, this disclosure may include theAtorney Docket No. : AUR6356WOPCT1Electronically Filed language, for example, “[element A], [element B], and / or [element C] ” This language may refer to either of the elements or any combination thereof. For instance, “A, B, and / or C” may refer to “A,” “B,” “C,” “A and B,” “A and C,” “B and C,” or “A, B, and C.”

Claims

Atorney Docket No. : AUR6356WOPCT1Electronically FiledCLAIMSWhat is claimed is:

1. A method performed by a surgical robotic system, the method comprising: while a magnetic brake of the surgical robotic system is engaged such that a joint of a robotic arm of the surgical robotic system is locked in place, applying power to the magnetic brake; measuring an input current of the magnetic brake; determining whether the input current comprises any peaks; determining a status of the magnetic brake based on the determining of whether the input current comprises any peaks; and providing a notification indicating the status of the magnetic brake.

2. The method of claim 1, wherein the magnetic brake comprises a brake housing, a ferromagnetic plate, and a coil, wherein the magnetic brake is engaged when the ferromagnetic plate is in contact with the brake housing, wherein applying power comprises supplying a current to the coil to produce a magnetic field to cause the ferromagnetic plate to disengage from the brake housing.

3. The method of claim 2, wherein the magnetic field is a first magnetic field, wherein brake housing comprises a permanent magnet that is arranged to produce a second magnetic field to pull the ferromagnetic plate towards the brake housing, wherein the first magnetic field causes the ferromagnetic plate to disengage by canceling or reducing the second magnetic field.

4. The method of claim 2, wherein responsive to a determination that the input current includes one peak, the status of the magnetic brake is disengaged such that the ferromagnetic plate is no longer in contact with the brake housing.

5. The method of claim 4 further comprising determining whether the one peak has a magnitude that is greater than a threshold, wherein responsive to a determination that the one peak has the magnitude that is less than the threshold, the status of the magnetic brake is a slow disengagement in which the ferromagnetic plate separates from the brake housing over a period of time.Atorney Docket No. : AUR6356WOPCT1Electronically Filed6. The method of claim 5, wherein responsive to a determination that the one peak has the magnitude that is greater than the threshold, the status of the magnetic brake is a disengagement in which the ferromagnetic plate separates from the brake housing within the period of time.

7. The method of claim 4 further comprising, responsive to the status of the magnetic brake being disengaged, providing a control signal to a motor of the joint to move at least a portion of the robotic arm.

8. The method of any of the preceding claims, wherein the magnetic brake comprises a disk and a brake housing, wherein, responsive to a determination that the input current comprises two or more peaks, the status of the magnetic brake indicates that the disk is misaligned along at least one axis with respect to the brake housing.

9. The method of any preceding claim further comprising, responsive to a determination that the input current comprises only one peak, determining whether an amplitude of the peak is greater than a threshold, wherein, responsive to the amplitude being greater than the threshold, the status of the magnetic brake indicates that the magnetic brake performed a single discrete movement in less than a time threshold to disengage , and wherein, responsive to the amplitude being less than the threshold, the status of the magnetic brake indicates that the magnetic brake performed the single discrete movement longer than the time threshold to disengage.

10. The method of any preceding claim, wherein providing the notification comprises displaying a visual notification on a display of the surgical robotic system or playing back an audible notification on one or more speakers of the surgical robotic system.

11. The method of any preceding claim further comprising activating a motor of the joint to move the robotic arm responsive to the status of the magnetic brake indicating that the magnetic brake is disengaged.Atorney Docket No. : AUR6356WOPCT1Electronically Filed12. The method of claim 11 further comprising: receiving input indicating that the magnetic brake is to transition from being disengaged to engaged; responsive to the input, putting the motor into a position holding mode; ceasing to apply the power to the magnetic brake; determining whether the status of the magnetic brake indicates that the magnetic brake is engaged; and responsive to determining that the status of the magnetic brake indicates that the magnetic brake is engaged, deactivating the motor.

13. The method of claim 12, wherein, responsive to determining that the status of the magnetic brake indicates that the magnetic brake is not engaged, providing a notification indicating that the status of the magnetic brake as an unsuccessful engagement; and maintaining the motor in the position holding mode.

14. The method of claim 12 further comprising: iteratively applying the power and ceasing to apply the power to the magnetic brake to determine whether the status of the magnetic brake changes from disengaged to engaged; at each iteration, determining whether a number of iterations exceeds a threshold; responsive to the number of iterations exceeding the threshold, providing a notification indicating the status of the magnetic brake as an unsuccessful engagement.

15. A method performed by a surgical robotic system, the method comprising: applying power to a magnetic brake of a robotic component of the surgical robotic system; determining that the magnetic brake has disengaged responsive to the applied power; determining an input current at which the magnetic brake disengaged based on the applied power; and adjusting the applied power to the magnetic brake based on the input current, while the magnetic brake remains disengaged.Atorney Docket No. : AUR6356WOPCT1Electronically Filed16. The method of claim 15, wherein applying the power comprises incrementally increasing the power applied to the magnetic brake until it is determined that the magnetic brake has disengaged.

17. The method of any preceding claim, wherein determining the input current comprises detecting a peak of the input current, wherein the applied power is adjusted based on the peak.

18. The method of claim 17, wherein applying the power comprises supplying an initial current to the magnetic brake, wherein adjusting the applied power comprises reducing the power based on a difference between the peak of the input current and the initial current.

19. The method of claim 15, wherein the magnetic brake comprises a disk, a brake housing, and a coil, wherein the magnetic brake disengages when the disk moves away from the brake housing due to a magnetic field produced by the coil responsive to the applied power.

20. The method of claim 19, wherein applying the power comprises applying a voltage to the coil of the magnetic brake, wherein adjusting the applied power comprises reducing the voltage based on the input current and a resistance of the coil.

21. The method of any preceding claim further comprising: measuring one or more characteristics of the magnetic brake; determining a temperature of the magnetic brake based on the one or more characteristics; and responsive to the temperature being greater than a threshold, ceasing to apply the power to the magnetic brake.

22. The method of claim 21, wherein the one or more characteristics comprises an applied voltage to the magnetic brake, wherein the temperature is determined based on the input current and the applied voltage.

23. The method of claim 15 further comprising:Atorney Docket No. : AUR6356WOPCT1Electronically Filed receiving sensor data from one or more sensors of the surgical robotic system; determining that the magnetic brake is disengaged based on the sensor data; and providing a notification indicating that the magnetic brake is disengaged.

24. The method of claim 23, wherein the magnetic brake comprises a disk and a brake housing, wherein determining that the magnetic brake is disengaged comprises determining that there is a gap between the disk and the brake housing that comprises a width that is greater than a threshold based on the sensor data.

25. The method of claim 24, wherein the one or more sensors comprises at least one of an image capturing device, a proximity sensor, and a contact sensor.

26. A method performed by a surgical robotic system, the method comprising: ceasing to apply power to a magnetic brake to transition the magnetic brake from being disengaged to engaged; measuring an input current of the magnetic brake; determining whether the magnetic brake has successfully engaged based on the input current; and providing a notification indicating a status of the magnetic brake as being engaged.

27. The method of claim 26, wherein the magnetic brake is part of a joint that comprises a motor for moving a portion of a robotic arm, wherein the method further comprises putting the motor into a position holding mode to prevent the portion of the robotic arm from moving.

28. The method of claim 27 further comprising, responsive to a determining that the magnetic brake has successfully engaged, deactivating the motor.

29. The method of any preceding claim further comprising cycling between applying the power and ceasing to apply power to the magnetic brake for at least a period of time, wherein responsive to failing to determine that the magnetic brake has successfully engaged within the period of time, the magnetic brake is determined to have unsuccessfully engaged.Atorney Docket No. : AUR6356WOPCT1Electronically Filed30. The method of claim 29, wherein the cycling comprises a number of attempts to successfully engage the magnetic brake, wherein the notification is provided after the number of attempts exceeds a predefined threshold.

31. The method of any preceding claim, wherein the magnetic brake comprises a brake housing, a disk, and a coil, wherein the magnetic brake is engaged when the disk is in contact with the brake housing, supplying power to the magnetic brake causes the coil to produce a magnetic field to cause the disk to disengage from the brake housing.

32. The method of any preceding claim, wherein determining whether the magnetic brake has successfully engaged comprises determining whether the input current comprises at least one peak responsive to the power ceasing to be supplied.

33. A surgical robotic system comprising: a robotic component that includes a joint with a magnetic brake; at least one processor; and memory having instructions which when executed by the at least one processor causes the surgical robotic system to: supply power to a coil of the magnetic brake of the robotic component in order to disengage the magnetic brake from an engaged state, detect an input current of the coil; detect a peak within the input current; adjust the power supplied to the coil based on the detected peak, wherein the magnetic brake remains disengaged while the power is adjusted.

34. The surgical robotic system of claim 33, wherein the memory has further instructions to increase the power supplied to the coil until the peak is detected within the input current.

35. The surgical robotic system of any preceding claim, wherein the power is supplied by providing a current to the coil, wherein adjusting the power supplied comprises reducing the supplied power based on a difference between the peak within the input current and the provided current to the coil.Atorney Docket No. : AUR6356WOPCT1Electronically Filed36. The surgical robotic system of any preceding claim, wherein the memory has further instructions to provide a notification indicating a status of the magnetic brake as being successfully disengaged based on the detected peak within the input current.

37. The surgical robotic system of any preceding claim, wherein the peak is a first peak, wherein the memory has further instructions to detect a second peak that is subsequent to the first peak, wherein the power is adjusted based on a difference between the second peak within the input current and a current value associated with the supplied power.

38. The surgical robotic system of claim 37, wherein the memory has further instructions to provide a notification indicating that a disk of the magnetic brake is misaligned along at least one axis.

39. The surgical robotic system of any preceding claim, wherein the memory has further instructions to increase power supplied to the coil until either 1) a determination has been made that the magnetic brake has successfully disengaged based on the detected peak within the input current or 2) a duration to disengage the magnetic brake has exceeded a threshold.

40. A surgical robotic system comprising: a robotic arm that includes a joint and a magnetic brake that comprises a permanent magnet and a ferromagnetic plate; at least one processor; and memory having instructions which when executed by the at least one processor causes the surgical robotic system to: apply power to the magnetic brake to cause the ferromagnetic plate to be disengaged from the permanent magnet, thereby allowing the joint to move the robotic arm; provide a control signal to a motor of the joint to move the robotic arm; cease applying the power to the magnetic brake to cause the ferromagnetic plate to be engaged with the permanent magnet, thereby preventing the joint from moving the robotic arm; measure an input current of the magnetic brake as a function of time; determine whether the input current comprises one or more peaks;Atorney Docket No. : AUR6356WOPCT1Electronically Filed determine a status of the magnetic brake based on a determination of whether the input current comprises one or more peaks; and provide a notification that indicates the status of the magnetic brake.

41. The surgical robotic system of claim 40, wherein the memory has further instructions to put the motor of the joint into a position holding mode prior to ceasing the application of power to the magnetic brake.

42. The surgical robotic system of claim 41, wherein, responsive to determining that the status of the magnetic brake indicates that the brake has engaged, deactivating the motor.43 The surgical robotic system of any preceding claim, wherein, responsive to determining that the input current comprises two peaks, determining the status of the magnetic brake as a misaligned successful engagement.

44. A system as shown and as described herein.

45. An electronic device as shown and as described herein.

46. A processor configured to perform one or more operations as described herein.

47. A non-transitory machine-readable medium that includes instructions which when executed by one or more processors causes an electronic device to perform one or more operations as described herein.

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