CN114929150A

CN114929150A - Engagement and/or homing of surgical tools in a surgical robotic system

Info

Publication number: CN114929150A
Application number: CN201980103240.5A
Authority: CN
Inventors: 周仁斌; 于浩然; S·N·科萨里
Original assignee: Verb Surgical Inc
Current assignee: Verb Surgical Inc
Priority date: 2019-10-23
Filing date: 2019-10-29
Publication date: 2022-08-19
Also published as: EP4048183A1; WO2021080623A1; JP7532513B2; KR20220082913A; EP4048183A4; JP2023508628A

Abstract

Motor controlled engagement and/or homing for surgical tools in a surgical robotic system is provided. In case two or more motors are used to control the same movement, the motors may be used to detect engagement even if no physical stops are provided. The motors operate in opposition to each other or in a manner that does not attempt the same motion, resulting in one of the motors acting as a stop for the other motor in engagement. A change in motor operation then indicates the engagement. The engaged motor and the known angle of the transmission linking the motor drive to the surgical tool indicate the original or current position of the surgical tool.

Description

Engagement and/or homing of surgical tools in a surgical robotic system

Technical Field

Embodiments relate to a control unit for detecting successful engagement and/or homing of a surgical robotic tool with one or more actuators in a surgical robotic arm of a surgical robotic system. Other embodiments are also described.

Background

The surgical robotic system gives an operator or user, such as an operating surgeon, the ability to perform one or more actions of a surgical procedure using the surgical robotic system. In the surgical robotic system, a surgical tool or instrument (such as an endoscope, a clamp, a cutting tool, a spreader, a needle, an energy emitter, etc.) is mechanically coupled to a robotic joint of a surgical robotic arm such that movement or actuation of the robotic joint directly causes rotation, pivoting, or linear movement of a portion of the tool (e.g., rotation of an endoscopic camera, pivoting of a gripper jaw, or translation of a needle). Once the tool is attached to (e.g., contacts) the tool driver in the arm, the operator command may cause movement and activate the function of the attached tool, such as closing the clamp, adjusting the curve of the endoscope, extending the instrument out of the cannula wall, pressurizing with a clamping tool, and other movements and actions.

Due to the different nature of the surgical procedure, different surgical tools or instruments may be selectively attached to the same arm of the surgical robotic system before and during the surgical procedure. To avoid equipment failure during surgery, it is important that the surgical tool or instrument not only be attached to, but also mechanically engaged with, the robotic joint of the surgical robotic arm. That is, prior to use of the surgical tool during a surgical procedure, the mechanisms in the surgical tool that impart motion or enable activation of instrument features (e.g., opening, closing, cutting, pressurizing, etc.) should mechanically engage with actuators in a tool driver in an arm of the surgical robotic system.

Disclosure of Invention

By way of introduction, the preferred embodiments described below include methods, systems, instructions, and computer readable media for engaging and/or homing motor controls for surgical tools in a surgical robotic system. In case two or more motors are used to control said same movement, the motors may be used to detect engagement even if no physical stops are provided. The motors operate opposite to each other or in a manner that does not attempt the same motion, resulting in one of the motors acting as a stop for the other motor in the joint. Then, a change in motor operation indicates engagement. The known angle of the engaged motor and the transmission linking the motor drive to the surgical tool indicates the original or current position of the surgical tool.

In a first aspect, a method for engaging motor control of a surgical tool in a surgical robotic system is provided. The first and second motors connected to the first and second drive disks, respectively, are caused to rotate. The first and second drive disks are in contact with the first and second tool disks. Both the first tool tray and the second tool tray are linked to a surgical tool. The first and second motors rotate such that the first and second drive disks rotate in opposition to one another to move the surgical tool. The engagement of the first and second motors with the first and second disks, respectively, is detected by a change in the performance of the first and second motors.

In a second aspect, a surgical robotic system for motor controlled engagement in a robotic surgical system is provided. The surgical tool is coupled to the first and second rotary tool pads via a transmission. The surgical tool is coupled such that rotation of the first and second rotary tool pads rotates the surgical tool. The tool driver has a first rotary driver and a second rotary driver cooperable with the first rotary tool pad and the second rotary tool pad; the processor is configured to detect the engagement of the first and second rotary tool pads with the first and second rotary drivers by a change in the signal.

In a third aspect, a method for homing a rotational position of a surgical tool in a surgical robotic system is provided. Engagement of the first and second rotary tool pads with the first and second rotary drivers is detected. Once engagement is detected, the rotational angle of the surgical tool linked to the first and second rotary tool pads is determined according to the first and second rotational angles of the first and second rotary drivers.

The present invention is defined by the following claims, and nothing in this section should be taken as a limitation on those claims. Other aspects and advantages of the invention are discussed below in conjunction with the preferred embodiments and may be subsequently claimed independently or in combination.

Drawings

Embodiments of the invention are illustrated by way of example, and not by way of limitation, in the figures of the accompanying drawings in which like reference numerals refer to similar elements. It should be noted that references to "an" or "one" embodiment of the invention in this disclosure are not necessarily to the same embodiment, and they mean at least one. In addition, in the interest of brevity and minimization of the overall number of figures, a given figure may be used to illustrate features of more than one embodiment of the invention, and not all elements in a figure may be required for a given embodiment.

FIG. 1 is a pictorial view of an exemplary surgical robotic system in a surgical site;

FIG. 2 is an illustration of a system for detecting engagement of a surgical tool with a tool driver of a surgical robotic arm;

FIG. 3 is a block diagram showing a surgical tool, a tool driver and a control unit;

4A-4C illustrate different states of the tool disk and the drive disk during the engagement process;

FIG. 5A is a flowchart illustrating a process performed by the control unit to engage a surgical tool with the tool driver;

fig. 5B is a flow chart illustrating another process for the control unit to detect engagement of the tool disc with the drive disc based on one or more operating parameters of the actuator driving the drive disc;

FIG. 5C is a flow chart illustrating another process of the control unit for detecting engagement of a surgical tool with a tool driver of the surgical robotic system;

FIG. 6 shows a block diagram of a feedback loop; and is provided with

Fig. 7 shows a block diagram of a controller for a feedback loop.

Fig. 8 illustrates an example of the rotational angular relationship between the motor and the corresponding drive disk, tool disk and surgical tool.

FIG. 9 illustrates one embodiment of a drive current for bonding.

Fig. 10 is a flow chart illustrating another process of the control unit for detecting engagement and/or for homing.

Detailed Description

Embodiments of apparatuses, systems, and methods for detecting engagement of a detachable surgical robotic tool with a tool driver of a surgical robotic arm of a surgical robotic system are described herein. In the following description, numerous specific details are set forth to provide a thorough understanding of embodiments. One skilled in the relevant art will recognize, however, that the techniques described herein can be practiced without one or more of the specific details, or with other methods, components, materials, and so forth. In other instances, well-known structures, materials, or operations are not shown or described in detail to avoid obscuring certain aspects.

Reference throughout this specification to "one embodiment" or "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the present invention. Thus, the appearances of the phrases "in one embodiment" or "in an embodiment" in various places throughout this specification are not necessarily all referring to the same embodiment. Furthermore, the particular features, structures, or characteristics may be combined in any suitable manner in one or more embodiments, such as those shown in the various figures.

Referring to fig. 1, there is a pictorial view of an exemplary surgical robotic system 100 in a surgical site. The surgical robotic system 100 includes a user console 102, a control tower 103, and one or more surgical robotic arms 104 at a surgical platform 105 (e.g., table, bed, etc.). The surgical robotic system 100 may incorporate any number of devices, tools, or accessories for performing a surgical procedure on a patient 106. For example, the surgical robotic system 100 may include one or more surgical tools 107 for performing a surgical procedure. The surgical tool 107 may have an end effector at its distal end (also the distal end of the surgical robotic arm 4 to which the surgical tool 107 is attached) for performing a surgical operation such as cutting, grasping, extending, or energy firing.

Each surgical tool 107 may be manually manipulated, robotically manipulated, or both during a surgical procedure. For example, the surgical tool 107 may be a tool for accessing, viewing, or manipulating the internal anatomy of the patient 106. In one embodiment, the surgical tool 106 is a grasper that can grasp tissue of a patient. The surgical tool 106 may be directly manually controlled by the bedside operator 108; or it may be robotically controlled via sending electronic commands to actuate movement of the surgical robotic arm 104 to which the surgical tool 106 is attached. The surgical robotic arm 104 is shown as a table-mounted system, but in other configurations, the surgical robotic arm 104 may be mounted on a cart, ceiling, or sidewall, or in another suitable structural support.

Generally, a remote operator 109 (such as a surgeon) may use the user console 102 to remotely manipulate the surgical robotic arm 104 and attached surgical tool 107, e.g., teleoperation. The user console 102 may be located in the same operating room as the rest of the surgical robotic system 100, as shown in fig. 1. However, in other environments, user console 102 may be located in an adjacent or nearby room, or it may be located at a remote location, e.g., in a different building, city, or country. User console 102 may include a seat 110, foot-operated controls 113, one or more handheld User Interface Devices (UIDs) 114, and at least one user display 115 configured to display a view of a surgical site within patient 106, for example. In the exemplary user console 102, a remote operator 109 sits in a seat 110 and views a user display 115 while manipulating foot-operated controls 113 and a handheld UID 114 in order to remotely control the surgical robotic arm 104 and surgical tool 107 (which is mounted on a distal end of the surgical robotic arm).

In some variations, the bedside operator 108 may also operate the surgical robotic system 100 in an "on-bed" mode, where the bedside operator 108 (user) is now located to one side of the patient 106 and concurrently manipulates i) a robot-driven tool (having an end effector) attached to the surgical robotic arm 104, e.g., holding the handheld UID 114 in one hand, and ii) a manual laparoscopic tool. For example, the left hand of the bedside operator may manipulate the handheld UID to control the surgical robotic components, while the right hand of the bedside operator may manipulate manual laparoscopic tools. Thus, in these variations, the bedside operator 108 may perform both robot-assisted minimally invasive surgery and manual laparoscopic surgery on the patient 106.

During an exemplary procedure (surgical procedure), the patient 106 is prepared and draped in a sterile manner to achieve anesthesia. Initial access to the surgical site (to facilitate access to the surgical site) may be performed manually while the arms of the surgical robotic system 100 are in the stowed configuration or the withdrawn configuration. Once access is complete, initial positioning or preparation of the surgical robotic system 100, including its surgical robotic arm 104, may be performed. The surgical procedure then continues with remote operator 109 at user console 102 manipulating the various end effectors and possibly the imaging system using foot-operated controls 113 and UID 114 to perform the surgical procedure. Manual assistance may also be provided at the operating bed or table by bedside personnel (e.g., bedside operator 108) who are wearing sterile surgical gowns, who may perform tasks on one or more of the arms of the surgical robotic arm 104, such as retracting tissue, performing manual repositioning, and tool replacement. Non-sterile personnel may also be present to assist the remote operator 109 at the user console 102. When a procedure or surgical procedure is completed, the surgical robotic system 100 and user console 102 may be configured or set in a state that facilitates post-operative procedures (such as cleaning or sterilization) as well as healthcare records being entered or printed via the user console 102.

In one embodiment, remote operator 109 holds and moves UID 114 to provide input commands to move robotic arm actuator 117 in surgical robotic system 100. UID 114 may be communicatively coupled to the rest of surgical robotic system 100, for example, via console computer system 116. UID 114 may generate spatial status signals corresponding to movement of UID 114, such as the position and orientation of the hand-held housing of the UID, and the spatial status signals may be input signals that control movement of robotic arm actuator 117. The surgical robotic system 100 may use control signals derived from the spatial state signal to control the proportional motion of the actuator 117. In one embodiment, a console processor of console computer system 116 receives the spatial status signals and generates corresponding control signals. Based on these control signals that control how actuator 117 is energized to move a section of surgical robotic arm 104, movement of a corresponding surgical tool attached to the arm may simulate movement of UID 114. Similarly, the interaction between remote operator 109 and UID 114 may generate, for example, a grip control signal that causes the jaws of the grasper of surgical tool 107 to close and grasp tissue of patient 106.

The surgical robotic system 100 may include several UIDs 114, with a respective control signal generated for each UID controlling an actuator and a surgical tool (end effector) of a respective surgical robotic arm 104. For example, the remote operator 109 may move the first UID 114 to control movement of an actuator 117 located in the left robotic arm, where the actuator responds by moving a link, gear, etc. in the surgical robotic arm 104. Similarly, movement of the second UID 114 by the remote operator 109 controls movement of another actuator 117, which in turn moves other links, gears, etc. of the surgical robotic system 100. The surgical robotic system 100 may include a right surgical robot arm 104 secured to a bed or table on the right side of the patient, and a left surgical robot arm 104 located on the left side of the patient. The actuator 117 may comprise one or more motors that are controlled such that they drive the joint rotation of the surgical robotic arm 104 to change the orientation of an endoscope or grasper of a surgical tool 107 attached to the arm, e.g., relative to a patient. The motion of several actuators 117 in the same surgical robotic arm 104 may be controlled by spatial state signals generated from a particular UID 114. The UID 114 may also control the movement of the respective surgical tool graspers. For example, each UID 114 may generate a respective gripping signal to control movement of an actuator (e.g., a linear actuator) that opens or closes jaws of the grasper at a distal end of the surgical tool 107 to grasp tissue within the patient 106.

In some aspects, communication between the surgical platform 105 and the user console 102 may be through a control tower 103 that may translate user commands received from the user console 102 (and more particularly from the console computer system 116) into robotic control commands transmitted to the surgical robotic arm 104 on the surgical platform 105. The control tower 103 may also transmit status and feedback from the surgical platform 105 back to the user console 102. The communication links between the surgical platform 105, the user console 102, and the control tower 103 may use any suitable data communication protocol of a variety of data communication protocols via wired and/or wireless links. Any wired connection may optionally be built into the floor and/or walls or ceiling of the operating room. The surgical robotic system 100 may provide video output to one or more displays, including a display in an operating room and a remote display accessible via the internet or other network. The video output or feed may also be encrypted to ensure privacy, and all or part of the video output may be saved to a server or electronic healthcare recording system.

Fig. 2 is an illustration of a subsystem or portion of the surgical robotic system 100 for detecting engagement of a surgical tool 240 with a tool driver 230 of a surgical robotic arm 220. The surgical robotic arm 220 may be one of the surgical robotic arms 104 of the surgical robotic system 100 shown and discussed with respect to fig. 1. The control unit 201 may be part of a control tower in fig. 1, for example. As discussed in more detail herein, engagement may be detected by the control unit 210 based on one or more motor operating parameters of one or more actuators (e.g., actuator 238-j) in the tool driver 230.

There are tool drivers 230 to which different surgical tools (e.g., surgical tool 240, as well as other detachable surgical tools — not shown) can be selectively attached (one at a time). This can be done by the following procedure: for example, a human user holds the housing of the surgical tool 240 in her hand and moves the housing in the direction of the illustrated arrow 280 until the outer surface of the surgical tool 240 in which one or more tool disks (e.g., tool disk 244-i) are present contacts the outer surface of the tool driver 230 in which one or more drive disks (e.g., drive disk 234-j) are present. In the example shown, tool driver 230 is a section of surgical robotic arm 220 at a distal end portion of surgical robotic arm 220. The proximal portion of arm 220 is secured to a surgical robotic platform, such as an operating table, not shown in fig. 2 but an example of which is visible in fig. 1 above.

Control unit 210 is responsible for controlling the movement of the various motorized joints in surgical robotic arm 220 (including drive disk 234) through which the operation of end effector 246 (its position and orientation and its surgical function) is accomplished, which mimics the operation of user input devices. This is accomplished via mechanical gearing in the surgical tool 240 when the surgical tool 240 has been engaged to transmit force or torque from the tool driver 230. The control unit 210 may be implemented as a programmed processor, for example, as part of the control tower 103 in fig. 1. It may respond to one or more user commands received via local or remote user input (e.g., a joystick, touch control, wearable device, or other user input device communicating via the console computer system 116). Alternatively, the control unit 210 may be responsive to one or more autonomous commands or controls (e.g., received from a trained surgical machine learning model executed by the control unit 210 or by the console computer system 116), or a combination thereof. These commands instruct the movement of the robotic arm 220 and the operation of its attached end effector 246.

End effector 246 may be any surgical instrument, such as a jaw, cutting tool, endoscope, spreader, implant tool, and the like. Different surgical tools, each having a different end effector, may be selectively attached (one at a time) to the robotic arm 220 for use during a surgical or other medical procedure. The end effector 246 shown in the example of fig. 2 is a jaw located at a distal end of the surgical tool 240, and the jaw may be retracted into or extended out of the illustrated cannula (e.g., a thin tube that may be inserted into a patient undergoing a surgical procedure).

The robotic arm 220 includes a tool driver 230 in which one or more actuators, such as actuator 238-j, are present. Each actuator may be a linear or rotary actuator having one or more respective motors (e.g., brushless permanent magnet dc motors), the drive shafts of which may be coupled to respective drive discs 234-j through a transmission (e.g., a gear train-not shown-that achieves a given gear reduction ratio). The tool driver 230 includes one or more drive discs 234, which may be disposed on a planar or flat surface of the tool driver 230, wherein the figure shows several such drive discs disposed on the same plane of the flat surface. Each drive disk (e.g., drive disk 234-j) is exposed on an outer surface of the tool driver 230 and is designed to mechanically engage (e.g., securely fasten via snap, friction, or other mating features) a mating tool disk 244-j of the surgical tool 240 to enable direct torque transfer therebetween. This may occur, for example, when a planar or flat surface of the surgical tool 240 and a corresponding or mating planar or flat surface of the tool driver 230 contact one another.

Further, a motor driver circuit (not shown, but which may be mounted, for example, in the tool driver 230 or elsewhere in the surgical robotic arm 220) is electrically coupled to the input drive terminals of the constituent motors of one or more of the actuators 238. The motor driver circuit manipulates the electrical power drawn by the motor in accordance with motor driver circuit inputs, which may be set or controlled by the control unit 210, to cause powered rotation of the associated drive disk (e.g., drive disk 234-j), to adjust, for example, the speed of the motor or its torque.

When the mating drive discs 234-j are mechanically engaged to the corresponding tool discs 244-j, powered rotation of the drive discs 234-j rotates the tool discs 244-j, e.g., both discs may rotate as a unit, imparting motion on, for example, a link, gear, cable, chain, or other transmission within the surgical tool 240 for controlling movement and operation of an end effector 246 that may be mechanically coupled to the transmission.

Different surgical tools may have different numbers of tool trays based on the type of movement and the number of degrees of freedom in which their end effector performs the movement (such as rotation, articulation, opening, closing, extension, retraction, pressurization, etc.).

Further, within the surgical tool 240, more than one tool disk 244 may facilitate a single motion of the end effector 246 to achieve goals such as load sharing by two or more motors driving the mating drive disk 234, respectively.

In another aspect, within the tool driver 230, there may be two or more motors coupling their drive shafts (through gearing) to rotate the same output shaft (or drive disk 234) to share the load.

In yet another aspect, within the surgical tool 240, there is a transmission that converts torque from the two drive disks 234 (via the respective tool disks 244) for performing complementary actions in the same degree of freedom, e.g., a first drive disk 234-i rotates a drum within the housing of the surgical tool 230 to receive one end of a cable and a second drive disk 234-j rotates another drum within the housing of the surgical tool 230 to receive the other end of the cable. As another example, extension and retraction of the end effector along a single axis may be accomplished using two tool disks 234-i, 234-j, one for performing extension and the other for performing retraction (e.g., via different cables). This is in contrast to an actuator that also moves in one degree of freedom (e.g., extends and shortens longitudinally along a single axis of movement), but only requires a single tool tray to control its full range of movement. As another example, an actuator that moves in multiple degrees of freedom (such as wrist movement, movement along multiple axes, activation of an energy emitter other than end effector movement, etc.) may require the use of several tool discs (each engaged to a respective drive disc). In another type of surgical tool 240, a single tool disk 244 is sufficient to perform both extension and retraction motions via a direct input (e.g., gears). As another example, where the end effector 246 is a jaw, two or more tool trays 244 may cooperatively control the movement of the jaw for load sharing, as discussed in greater detail herein.

In some embodiments, when the surgical tool 240 is first attached to or mounted on the tool driver 230 such that the tool disk is substantially coplanar and coaxially aligned with the corresponding drive disk (although the tool disk and drive disk may not have been successfully engaged), the control unit 210 initially detects the type of surgical tool 240. In one embodiment, the surgical tool 240 has an information storage unit 242, such as solid state memory, RFID tag, bar code (including two-dimensional bar code or matrix bar code), etc., that identifies tool or end effector information for the surgical tool, such as one or more of: identification of the tool type or end effector type, a unique tool ID or end effector ID, the number of tool disks used, the positions of those tool disks used (e.g., from a total of six possible tool disks 244-e, 244-f, 244-g, 244-h, 244-i, 244-j), the type of transmission of the tool disks (e.g., direct drive, cable drive, etc.), which motion or actuation the end effector is imparted to the tool disks, one or more tool calibration values (e.g., rotational position of the tool disks determined during coefficient testing/assembly of the tool), whether the motion of the end effector is constrained by maximum or minimum movement, and other tool attributes. In one embodiment, the information storage unit 242 identifies minimal information, such as a tool ID, which the control unit 210 may use to perform a lookup of various tool attributes.

The tool driver 230 may include a communication interface 232 (e.g., a memory writer, near field communication, NFC, transceiver, RFID scanner, bar code reader, etc.) to read information from the information storage unit 242 and pass the information to the control unit 210. Further, in some embodiments, there may be more than one information storage unit in the surgical tool 240, such as one information storage unit associated with each tool tray 244. In this embodiment, the tool driver 230 may also include a corresponding sensor for storing each possible information element present in a given tool.

Joining

After the surgical tool 240 is attached with the tool driver 230 such that the tool discs are brought into alignment with and superimposed on the corresponding drive discs (although not necessarily mechanically engaged), and after the tool disc information is obtained, e.g. read by the control unit 210, the control unit 210 performs an engagement process to detect when all tool discs intended to be attached to the respective drive discs are mechanically engaged with their respective drive discs (e.g. their mechanical engagement has been achieved, or the tool driver is now considered to be engaged with the tool). That is, attaching the surgical tool 240 with the tool driver 230 does not necessarily ensure the proper fit required for mechanical engagement of the tool disk with the corresponding drive disk (e.g., due to misalignment of the mating features). The engagement process may include activating one or more motors that drive actuators (e.g., actuator 238-j) of the corresponding drive discs 234-j. Then, as discussed in more detail below, based on one or more monitored motor operating parameters of the actuator 238-j, mechanical engagement of the tool disk 244-i with the drive disk 234-j may be detected while the actuator is driving the drive disk 234-j. This process may be repeated for each drive disk 234 (in the tool driver 230) that is expected to be currently attached to a corresponding tool disk 244 (e.g., as determined based on tool disk information obtained for the particular surgical tool 240 currently attached).

Upon detecting that a particular type of surgical tool 240 has been attached to the tool driver 230, the control unit 210 activates one or more actuators (e.g., motors) of the tool driver 230 that have previously been associated with that type of surgical tool 240. In some embodiments, each actuator associated with a corresponding drive disk 234 of the surgical tool 240 may be activated simultaneously, serially, or a combination of simultaneous and serial activation. Fig. 3 shows an example of a surgical tool 240 that utilizes four tool trays, such as tool tray 244-i, that are arranged in a coplanar manner on a mating surface of its housing. Each tool tray facilitates at least a portion of the movement and/or activation of the end effector 246. Upon detecting that the surgical tool 240 is attached to the tool driver 230 (e.g., connection of the mating surfaces of the respective housings), the control unit 210 (or its processor 312 while executing instructions stored in memory 314, such as engagement controls 316) performs a process of determining that only the corresponding four drive disks (such as drive disks 234-j) need to be rotated (the corresponding actuators 238 need to be activated-see fig. 2) to perform the engagement process.

Returning to FIG. 2, during operation of the actuator 238-j, when the motor of the actuator is signaled to begin movement after the attachment of the surgical tool 240 to the tool driver 230 is detected, the one or more sensors 236-j measure one or more motor operating parameters of the actuator 238-j. In one embodiment, the actuator 238-j will rotate in a direction that causes the tool tray 244-i to which it is attached (but not yet engaged), thereby spooling the cable in the transmission housing of the tool 240 for a cable-driven surgical tool. See, for example, fig. 4A, where movement 445 of the tool tray 244 prevents unwinding of the cable 446, and thereby holds the tool tray 244 in place or begins to rotate the tool tray 244 in the direction of the movement 445 (which winds the cable 446). This rotation of the tool plate 244 continues until engagement is achieved, as further described below in connection with fig. 4B and 4C.

In another embodiment, the selected actuator is signaled to turn in order to rotate its attached tool disk 244 such that the end effector 246 connected to the tool disk 244 moves toward a physical constraint (e.g., jaws open until it abuts a cannula wall, maximum range of motion is achieved when hitting a hard stop in a fully open position, etc.). In yet another embodiment, such as an endoscopic embodiment, where the two actuators share a load that is the rotation of the endoscopic camera, where there may be no hard stop to prevent rotation of the camera, the selected actuator has its attached tool disk 244-i rotating in the opposite direction of the motion of the other tool disk 244-j, which is also rotatably coupled to the same output shaft in the transmission housing of the tool 240. In that case, once one of the tool trays 244-i, 244-j is engaged, that tool tray will act as a physical restraint to the other tool tray. Other predetermined directions of movement may also be used consistent with the discussion herein.

Further, in some embodiments, the movement of the actuator is ramped or ramped up by the control unit 210 (e.g., the control unit 210 signals or commands the actuator to begin rotation at a low speed at the beginning of movement, then gradually increase the speed, and then gradually decrease the speed when engagement is detected).

In one embodiment, calibration values stored in the information storage unit 242 of the surgical tool 246 can be used to speed tool engagement. For example, the calibration values may include factory-determined positions (angles) of the particular tool tray 244-j recorded during product assembly or testing. The engagement process may require knowledge of the home position of the corresponding drive disk 234-j. This information may be obtained by the control unit 210 executing a tool driver calibration routine, wherein the control unit determines when a particular drive disk 234-j has reached an initial position (when the control unit actuates the drive disk 234-j) such that the position of that drive disk 234-j is now known to the control unit 210. It should be noted that the control unit 210 may do so while relying solely on the output from the position sensor in the tool driver 230, and the tool 240 itself may be passive in that it has no electronic sensor.

Next, the control unit 210 may activate the corresponding actuator of the driving disk 234-j, so that the driving disk 234-j rotates at a high speed until the position variable of the driving disk 234-j approaches the factory-determined position. When the drive plate satisfies a threshold distance relative to a factory-determined position (e.g., the home position of the tool plate), which means that the mating features of the tool plate and the mating features of the drive plate are closely aligned, the speed may be reduced in order to increase the likelihood that the mating features will engage each other when they initially meet. This process can be used for both direct drive and tool trays that use a cable to drive the actuator (as shown in fig. 4A). For the latter, the calibration values may include a rotation count (e.g., a number of complete rotations of the motor drive shaft) that may be used to limit continued rotation of the drive disk 234-j once engagement has been detected, thereby ensuring that the maximum wound length of the cable is not exceeded, or that the angle of rotation of the engaged tool disk 244-j and drive disk 234-j is not exceeded.

In some embodiments, the motor operating parameter monitored by the control unit 210 (via sensor 236) is interpreted as being indicative of successful mechanical engagement of the tool disc with the drive disc. These may include measurements of the torque applied by the actuator 238-j as measured by a torque sensor or force sensor, measurements of the current provided to the motor of the actuator in an attempt to drive the actuator 238-j to move at a particular rate (e.g., where the sensor 236-j may include a current sense resistor in series with the motor input drive terminal), a measurement of the electrical impedance seen in the input drive terminal of the motor entering the actuator when attempting to drive the motor at a particular rate of movement (e.g., where the sensor 236-j may also include a voltage sensing circuit to measure the voltage at the motor input drive terminal), the speed of the actuator 238-j (e.g., where the sensor 236-j may include a position encoder (sensor) on the output shaft of the actuator 238-j or on the drive shaft of the motor), and other parameters referred to herein as motor operating parameters. When the one or more motor operating parameters in a particular actuator are monitored, the detection of such a condition may be interpreted by the control unit 210 as a mechanical engagement event when one or more of the parameters meets (e.g., meets or reaches) a predetermined condition or threshold. It should be noted that the satisfaction of a predetermined condition may, for example, indicate that, according to a threshold value, the monitored operating parameter exhibits a specific variation with respect to an operating parameter of another motor that is part of the same actuator 238-j or of another actuator 238-i that is being simultaneously controlled by the control unit 210 during the engagement detection process.

In some embodiments, certain motor operating parameters are detected during operation of the actuator 238-j, such as one or more of: i) the control unit 210 uses these motor operating parameters to determine that mechanical engagement of the tool plate 244-j with the drive plate 234-j has occurred, such as torque that meets (e.g., rises and reaches) a torque threshold, ii) motor current that meets (e.g., rises and reaches) a current threshold, iii) electrical impedance that falls below an electrical impedance threshold, iv) motor speed that falls below a motor speed threshold, or a combination thereof. The following are some examples of such processes.

In one embodiment, where the tool disk 244-j uses the cable 446 to control the movement of its end effector 246, the actuator 238-j (which drives the corresponding drive disk 234-j) will move in the direction of the wound cable (where the direction of the motion 445 of the control unit 210 is known based on the type of tool 240 previously identified). Fig. 4A shows such a tool disk 244 having a pair of

coupling features

447a, 447b on its disk face, which are depicted as hollow circles. Each

coupling feature

447a, 447b may be a separate cylindrical cavity formed in the disk face. The direction of the movement 445 will wind the cable 446 therearound, wherein in this initial condition the cable 446 has some slack which, as shown, will disappear when the cable 446 is wound in the direction of the movement 445.

The drive disk 234 is concentrically aligned with the tool disk 244 as shown in fig. 4B. That is, fig. 4B shows the drive disk 234 aligned and superimposed over the tool disk 244 such that their respective disk faces contact each other. The driving disk 234 has a pair of

coupling features

448a, 448b on its disk surface, which are indicated as solid circles. Each

coupling feature

448a, 448b may be a separate barrel pin formed in the disk face. In this particular example, each of the coupling features 448 are sized to easily fit into either of the structures 447 (once the two complementary structures are aligned). In fig. 4B, structures 447a, 447B and structures 448a, 448B are not aligned even though their respective tool and drive disk faces contact each other. In other words, in FIG. 4B, one or more mating or complementary pairs of structures, such as structures 447a-448a or structures 447a-448B, are not mechanically engaged with each other. During such conditions, drive disk 234 continues to be driven by its actuator 238, moving (rotating) in the direction of motion 445 until mechanical engagement is achieved as shown in fig. 4C.

As shown in fig. 4C, driving disk 234 has reached a position where both coupling features 447a-448a and 447b-448b have mechanically engaged with each other as shown, such that they now move in unison (if driving disk 234 continues to rotate). In this example, each pin-cavity pair is now interlocked, as shown in this figure. Further, in this position, it is now proposed that the cable 446 has been wound up and thus may be used to help hold the tool tray 244 in place (prevent it from rotating) as the drive tray 234 continues to turn in the direction of motion 445. Further rotation of drive disc 234 in the case of fig. 4C may increase the tension of cable 446 because cable 446 pulls its end effector 246 until reaching a hard stop that forms a physical constraint that prevents further movement in the direction of motion 445 of drive disc 234 in the engaged state.

The physical restriction of further rotation of drive disc 234 enables detection of a mechanical engagement event by control unit 210, which measures and compares motor operating parameters to one or more thresholds that may have been predetermined as an indication of engagement. For example, a drop in the speed/velocity of the motor below one or more thresholds indicates engagement because further movement of the motor in the winding direction is restricted. As another example, engagement occurs when the amount of torque applied by the motor increases to a value greater than that of a free-running motor and/or greater than the friction generated by the tool disk and the drive disk and/or due to the attachment structures rubbing or sliding against each other prior to engagement. Similarly, in other embodiments, when engagement occurs and the motor is being powered on in an attempt to continue driving the disc in the predetermined direction, the measured current and/or impedance approaches and may reach a maximum predetermined value. When one or more of these thresholds are met, the control unit 210 may infer that engagement between the tool disc and the drive disc occurs.

The control unit 210 may use other forms of physical constraints to detect successful engagement of the drive disk with the tool disk. For example, mechanical limitations of motion constraints such as the range of motion imposed by the joints of the end effector (e.g., joints that may rotate only about an axis from-45 degrees to 45 degrees) or physical barriers that prevent movement (e.g., walls of a sleeve that impede movement of the end effector) may also be used as the physical constraints/hard stops described above for cable-driven or non-cable-driven tools.

In some embodiments, the surgical tool 240 may not have a physical constraint/hard stop in at least one degree of freedom of movement from which motor operating parameters may be measured. For example, tool disk 244-j may be responsible for imparting unconstrained rotation of the end effector 246 elements about an axis. However, even if there is such unrestricted movement, the control unit 210 may detect engagement of the drive disc 234-j with the tool disc 244-j by detecting changes in one or more motor operating parameters during the engagement detection process. For example, a pattern of motor operating parameters, such as repeated torque spikes caused by the rotation of structure 447 past structure 488 (and thus not engaging each other), indicates that engagement has not occurred. Thus, the cessation or absence of the torque spike pattern (as drive disk 234-j continues to rotate) means that the control unit 210 has detected engagement of the tool disk with the drive disk.

In some embodiments, the physical constraint may be created by using coordinated movement of multiple drive disks and/or by engaging a single drive disk before engaging the second drive disk. For example, consider the case where two or more tool trays (in the same housing of the surgical tool 240) are connected by a transmission in the housing of the tool 240 to share a load (end effector 246) when rotating in the same direction, such as when a cutting or gripping tool may need to exert more force than a single actuator 238-j can provide. In such embodiments, two or more actuators that are rotating in the same direction (whose respective drive disks are rotating in the same direction) are driving the same output shaft inside the surgical tool 240 (due to the gearing in the surgical tool 240 that is connected to the corresponding tool disk). Now, if both actuators are signaled to move in opposite directions, once one of the drive discs engages its corresponding tool disc, that drive disc becomes a physical constraint for the other drive disc (when the other drive disc has engaged its corresponding tool disc). When one of the two or more actuators is engaged (its drive disk engages its corresponding tool disk), the control unit 210 creates a constraint on the other actuator by signaling the engaged actuator, for example, to enter a position holding state. That is, the first actuator 238-j will be commanded by the control unit 210 to maintain its position while the other, unengaged actuator 238-i will continue to be signaled to drive it and thus rotate or move (toward engagement between its drive disk 234-i and tool disk 244-i). In this embodiment, one or both of the motor operating parameters of the actuator may be monitored to detect engagement between the tool disc and the pair of drive discs. Furthermore, if a hard stop does exist (which the control unit 210 expects or knows that this particular tool 240 has), the actuator of the engaged drive disk may be signaled to continue driving or rotating in the same direction until a hard stop is detected. The other actuator may continue to rotate in the opposite direction and attempt to engage, while the engaged actuator retains its position at the hard stop.

Returning to fig. 2, and as described above, the tool identification performed by the control unit 210 enables the control unit to obtain characteristics of the end effector 246 of the surgical tool 240. For example, the control unit 210 may use this identification process to determine whether two (or more) of the tool discs in the tool 240 cooperate to impart movement to the end effector, whether one or more movements of the end effector are limited by hard stops or physical constraints, what the range of movement of the end effector is, which actuators the tool 240 will use, and factory defined calibration values such as the original position of the tool disc. It should be noted that the calibration values may cover a range, for example, 290 degrees +/-4 degrees. Based on such calibration values, for example, the home position of the tool disk 244-i, and based on the current position of the corresponding drive disk 234-i (determined using the position encoder in the tool driver 230), the control unit 210 can track the difference during the engagement process (when the actuator is signaled to rotate). As long as the difference is greater than a predetermined threshold, a fast rotation (fast rotation) of the actuator is signaled and then a slow rotation (slow rotation) of the actuator is signaled in response to the difference becoming less than the threshold, meaning that the drive disc is approaching the calibrated value home position. And is expected to increase the chance of detecting a reliable engagement.

In some embodiments, after control unit 210 detects engagement, control unit 210 may take one or more additional actions with respect to end effector 246 to confirm engagement. For example, the control unit 210 may cause the end effector to perform a predetermined set of motions (one or more motions) to test engagement, e.g., signal the drive disk to reverse direction, thereby causing the end effector to move in the opposite direction (in which the end effector moves during the engagement process), move the end effector to achieve a desired maximum degree of movement, etc. Such movement enables the control unit 210 to, for example, again reach a hard stop or reach a physical constraint, which is detected based on one or more operating parameters as described herein, thereby confirming the mechanical engagement between the tool disc and the drive disc.

Further, in some embodiments, control unit 210 may utilize hard stops or physical constraints to set the reference position of the end effector. For example, knowing that a hard stop is reached when the end effector is rotated 270 ° in a certain direction, the control unit 210 can set calibration values corresponding to the position of the actuator or drive disk. The movement of the actuator or drive disc may then be tracked based on the number of rotations of the drive disc, the motor shaft, the gear ratio, the drive disc/motor index, etc.

Further, in some embodiments, the control unit 210 may signal actuation of a specified number of times, a specified number of rotations, or a combination thereof by one or more motors when attempting to achieve engagement of the tool plate with the drive plate. When engagement is not achieved within a threshold amount of time, number of rotations, etc., control unit 210 may issue a warning to an operator of the surgical robotic system (e.g., an operator of system 100 of fig. 1) to detach and then reattach surgical tool 240, thereby restarting the engagement process.

After the control unit 210 detects mechanical engagement of the drive disk with the tool disk, the operator may command movement of one or more joints of the surgical robotic arm 220. As described above, commands are received from or derived from one or more UIDs (e.g., UID 114) as spatial state signals from the UIDs that are converted into corresponding control signals that control unit 210 provides (e.g., desired motor speed or current and direction of rotation) to energize one or more actuators of tool driver 230, which will change the pose, position, or other state of the end effector. In one embodiment, where two or more actuators cooperatively control the motion of the end effector, such as when two or more tool trays impart motion to the end effector in the same degree of freedom, the control unit 210 further implements cooperative control techniques to ensure that the actuators operate in a complementary manner when moving the end effector, share loads associated with the movement of the end effector, do not oppose each other when imparting such motion, maintain balance between the actuators such that one actuator does not continuously perform more or less work than the other actuators, and so forth. For example, when two or more actuators are used to control the opening, closing, and application of clamping forces of the jaws of the end effector 246, the control unit utilizes a multi-actuator operation control technique that identifies a first of the two or more actuators as a master actuator and the remaining one or more actuators as slave actuators. Then, a position command is also provided that has been provided to signal the master actuator to move the end effector 246 to the commanded position, and a command is provided to signal the slave actuator to move the end effector 246 to the same commanded position. For example, if the master and slave actuators are repetitive, each slave actuator may also be provided with the same polarity and current value if the master actuator receives a certain polarity (the direction of rotation of its motor) and a certain motor current value to satisfy a given end effector position command. However, in some embodiments, there may be some compensation for the motion of the actuators that are complementary to each other, e.g., reversing the polarity of the slave actuator when the direction of rotation of the master and slave actuators is different, adjusting the gain (e.g., the gain of the commanded motor current) when the properties of the motors are different, etc., as discussed in more detail herein.

Fig. 3 is a block diagram showing an example of the surgical tool 240, the tool driver 230, and the control unit 210. The surgical tools 240 may be attached with the tool drivers 230 by bringing complementary or mating surfaces of their respective housings into contact with each other. Attaching may also include fastening the housings to one another. In addition, one or more sensors (not shown) of the tool driver 230 may be used by the control unit 210 to detect attachment, including reading data from the surgical tool 240 identifying the surgical tool 240, indicating which tool tray (e.g., tool tray 244-j) is used to control movement of the end effector 246, including calibration values, indicating whether the tool has hard stops, or indicating which tool tray facilitates movement of the surgical tool 240 or is connected to other tool trays in the surgical tool through a transmission. The data may be communicated to the control unit 210 via a communication link (e.g., a wired link or a wireless link) established between the communication interface 318 of the control unit 210 and sensor reading circuitry (not shown) in the tool driver 230. The data may then be stored in memory 314 as part of the engagement control program (engagement control 316) and may be associated with a particular surgical tool 240 as long as the latter remains attached to the tool driver 230.

The control unit 210, including its programmed processor 312, may be integrated into the surgical robotic system 100 (fig. 1), for example, as a shared microprocessor and program memory within the control tower 103. Alternatively, the control unit 210 may be implemented in a remote computer (such as in a room different from the operating room shown in fig. 1, or in a building different from the operating site). In addition, the control unit 210 may also include (although not shown) user interface hardware (e.g., keyboard, touch screen, microphone, speaker) that may enable manual control of the robotic arm and its attached tool 240, power devices (e.g., batteries), and other components typically associated with electronic devices for controlling the surgical robotic system.

The memory 314 is coupled to the one or more processors 312 (generally referred to herein as "processors" for simplicity) to store instructions for execution by the processors 312. In some embodiments, the memory is non-transitory and may store one or more program modules, including tool control 320 and engagement control 316, which instructions configure processor 312 to perform the engagement process described herein. In other words, the processor 312 may operate under the control of a program, routine, or execution of instructions stored in the memory 314 as part of the tool control 320 and as part of the engagement control 316 to perform a method or process in accordance with aspects and features described herein.

In response to detecting attachment of the surgical tool 240 to the tool driver 230, the engagement control 316 executes (or more precisely configures the processor 312 to execute) a process for detecting mechanical engagement of the tool tray with a corresponding drive tray (which is driven by the actuator), such as engagement of the tool tray 344-i with a corresponding drive tray 334-i. The engagement control 316 may signal (via the tool control 320) one or more of the actuators of the tool driver 230 to impart motion to their respective drive discs. In some embodiments, these instructions or signals include instructions to energize, activate, or otherwise provide power to the motor such that the motor can generate or apply a particular amount of torque, rotate the drive disk at a particular speed and direction by applying a particular voltage command, current command, or the like. Further, the movement of each drive disk may be controlled to start quickly initially during the engagement detection process and then ramp down slowly once engagement is approached, or mating features are detected to be near alignment, or a predetermined time limit is reached if engagement is not detected. For example, based on the relative position of the drive plate to the tool plate (which may be based on known calibration values), the actuator speed is ramped down to a predetermined speed (e.g., until the drive plate is within a threshold distance at which the mating features become aligned).

The engagement control 316 monitors one or more motor operating parameters of the motor of the actuator of the tool driver 230. As discussed herein, motor operating parameters may include the torque imparted by the motor, the voltage supplied to the motor, the electrical impedance seen at the input drive terminals of the motor when attempting to drive the motor at a particular rate of movement, the motor speed, and other motor operating parameters. One or more of these parameters may be monitored by comparing them to a threshold value, such that when the threshold value is reached, then a mechanical engagement event is deemed to have occurred (e.g., between the tool disc 344-i and the drive disc 334-i). As discussed herein, mechanical engagement is expected to be detected when the corresponding mating features of the tool disk and the corresponding mating features of the drive disk are aligned and secured to each other such that rotation of the drive disk will cause immediate and proportional rotation of, for example, the mechanically engaged tool disk (integral with the drive disk). Such engagement is expected to be detected when one or more of the motor operating parameters meets a threshold (e.g., reaches or exceeds a threshold, maximum torque, voltage, or electrical impedance value that indicates a hard stop has been reached, the torque, voltage, or impedance value being greater than that required to overcome the friction that initially occurred when the tool 240 was first attached to the tool driver 230). Thus, the engagement control 316 infers or deduces that the tool disk 344-i and the drive disk 334-j have engaged with each other (e.g., that the respective disk mating features are fastened to each other).

It should be noted that the engagement control 316 need not monitor sensor readings for all motor parameters obtained from the tool driver 230. Rather, the engagement control 316 may monitor only one or more features of interest based on, for example, whether the surgical tool 240 is limited by any hard stops or physical movement constraints, whether one or more tool trays cooperate (cooperate with each other) to impart movement to the surgical tool 240, whether a tool tray imparts movement to the surgical tool 240 via a cable or directly (e.g., through a gearbox), or a combination thereof, in order to determine when a threshold associated with engagement is met.

In some embodiments, the engagement control 316 monitors a pattern of motor operating parameters, such as a pattern of torque, voltage, motor speed, electrical impedance, etc., that is a result of driving the disk 234-j to rotate through the tool disk 244-j without mechanical engagement. That is, a specific amount of torque, force, voltage, etc. may be measured that is greater than that exhibited by a freely moving drive disk (where the surgical tool 240 is not attached to the tool driver 230) and less than that exhibited by a mechanically engaged drive disk (e.g., when the mating features of the tool and the drive disk are in communication with each other while the tool housing and the tool driver housing are in contact but not engaged). When this motor parameter pattern change is detected, such as due to encountering a hard stop or physical motion constraint, the engagement control 316 is deemed to have detected mechanical engagement. Monitoring and interpreting the pattern-based motor operation pattern also enables the engagement control 316 to detect engagement (between the tool disk 344-j and the drive disk 334-j), even if no hard stops or motion constraints are available, or drive the drive disk to a hard stop or other motion constraint of the tool is not necessary.

In some embodiments, when the engagement control 316 detects mechanical engagement of the tool tray with the drive tray, it may also initiate a verification process or engagement check, wherein the actuator of the tool driver 230 is signaled to undergo a predetermined set of one or more movements to verify the detected engagement. For example, the actuators may be instructed to rotate their respective drive discs in a direction opposite to the engagement direction (the engagement direction being the direction in which the drive discs rotate when engagement is initially detected, e.g., the direction of motion 445 shown in fig. 4A). The drive disk may then be rotated in a direction opposite the engagement direction until a second engagement is detected (e.g., when a particular motor parameter reaches a threshold that meets the condition that the tool disk reaches a hard stop or a motion constraint, when a particular motor parameter reaches a threshold that meets the condition that resistance against tool disk rotation is not caused by a friction-only condition, or a combination thereof).

Based on having detected engagement of the tool tray to the drive tray, or based on a countdown timer having expired without detection of engagement, the engagement control 316 generates a notification to an operator of the surgical robotic system. The notification may indicate that engagement has occurred so that the surgical tool 240 is ready for use, or that engagement has not occurred, and therefore that the surgical tool 240 should be reattached.

Fig. 5A is a flow chart illustrating a process 500 for engaging a surgical tool with a tool driver of a surgical robotic system according to an embodiment of the present disclosure. Process 500 may be performed by a programmed processor (also referred to herein as processing logic) configured according to software stored in a memory (e.g., processor 312 and memory 314 of fig. 3, where processor 312 is configured according to instructions of tool control 320 and engagement control 316).

Referring to fig. 5A, processing logic is initiated by activating an actuator of a tool driver to rotate a drive disk of the tool driver (processing block 502). For example, processing logic may activate a linear or rotary actuator of a tool driver (e.g., tool driver 230) to turn or rotate a drive disk (e.g., drive disk 234-j). Further, as discussed herein, when mechanically engaged, rotation of a drive disk (e.g., disk 234-j) will cause a corresponding tool disk (e.g., disk 244-j) of a surgical tool (e.g., surgical tool 240) to immediately or directly rotate.

Processing logic monitors one or more motor operating parameters of an actuator that rotates a drive disk when the motor is activated (processing block 504). In some embodiments, the operating parameters of the motor that are monitored may include torque, motor current, motor speed, or a combination thereof.

Based on the one or more monitored motor operating parameters, processing logic detects when the drive disk is mechanically engaged with the tool disk (processing block 506). In one embodiment, the detection is performed when or in response to at least one of the monitored one or more motor operating parameters meets a corresponding condition or threshold. For example, the condition may be associated with a value of a motor operating parameter that is generated in response to the motor reaching a physical constraint, preventing further rotation of the tool plate (e.g., reaching a mechanical limit of the range of motion when a physical obstruction to movement is encountered, reaching a maximum extent of movement of the end effector of the tool, opposing motion from another activated motor actuator, etc.). As another example, this condition may be manifested as a motor operating parameter that is exhibited when there is friction during rotation that is generated as the drive disk contacts and slides against the tool disk, but there is no mechanical latching or fastening of the drive disk to the tool disk. In the embodiments described herein, when mechanical engagement of the drive disk with the tool disk is detected, one or more additional actions may be performed by the processing logic, such as generating a system or operator notification, initiating one or more engagement verification operations, storing a reference value, and so forth.

Fig. 5B is a flowchart illustrating a process 550 for detecting engagement of the tool disc with the drive disc based on one or more motor operating parameters of an actuator driving the drive disc. The process 550 is performed by processing logic that may comprise any combination of hardwired circuitry and a programmed processor, where, for example, the process 550 may be performed by the processor 312 programmed according to the tool control 320 and the engagement control 316 described above. The process may begin by detecting that a detachable surgical tool has been attached to a tool drive of a robotic arm of a surgical robotic system (process block 552). The attachment may be detected based on when a sensor of the tool driver is within a wireless detection range or conductively connected with an information storage unit in the detachable surgical tool. As discussed herein, the information storage unit may include a tool identifier, and may also include additional tool attributes, such as which of several available tool trays in the tool housing are actually connected to the end effector in the detachable surgical tool through the transmission in the housing, which type of transmission in the tool controls movement of the end effector (e.g., cable drive, direct drive, etc.), which direction of movement or rotation is allowed (if any range of such movement or rotation exists), calibration values (e.g., cable length, current cable length, maximum wind-up, rotational position of the tool tray or home position of the tool tray, etc.), and other tool attributes discussed herein.

The at least one motor of the tool driver is then activated, causing the at least one motor to rotate corresponding to the associated drive disk of the tool disk (which is connected through a transmission in the surgical tool to control the motion of the end effector (processing module 554). In one embodiment, the current supplied to the motor, the torque or direction of movement achieved by the motor is signaled to the tool control 320 such that the motor will cause the drive disk to rotate in a predetermined direction at a predetermined speed Direct drive, etc.), the type of constraint that will be encountered (e.g., hard stop, physical constraint, relative motion constraint), or a combination of such factors. One or more motor operating parameters of at least one motor of the tool drive are then monitored (process block 556). The monitored motor operating parameters may correspond to those (e.g., torque, speed) that are controlled by the processing logic to cause the motor to move.

Returning to FIG. 5B, processing logic repeatedly checks to see if an engagement condition has been met, e.g., if a monitored motor operating parameter has reached a threshold (processing block 558). If so, a mechanical engagement event is flagged indicating that the drive disk has been mechanically engaged with its corresponding tool disk (process block 564). As discussed herein, the threshold indicates a condition associated with mechanical engagement of the drive disk. For example, mechanical engagement is expected to occur when the torque, current, or impedance associated with a predetermined speed or rate of the motor exceeds the values they associate with the values generated by the motor when the tool drive rubs against the tool disk alone. The threshold may be a value greater than the torque, voltage, impedance, etc. required to overcome such friction. As another example, the movement of the end effector may be subject to physical constraints such as the maximum range of motion of the joint, hard stops (e.g., imposed by the cannula wall), opposing motion of another drive disk, and other physical constraints. In that case, the speed and direction of movement of the motor are selected to advance the end effector or tool tray toward the physical constraint. Then, when the physical constraints are reached, the monitored torque, current, impedance will increase to a maximum value, and the speed will drop to zero. In this example, one threshold may refer to the torque or motor current set near its maximum value, and another threshold may refer to a speed set below the nominal speed of the motor during rotation of the drive disc, e.g., substantially zero. Thus, the two thresholds serve as a means of checking against each other to make the detection of the joint more robust.

In response to the detected engagement of the drive disk with the corresponding tool disk, the movement of the drive disk is stopped (process block 566). In one embodiment, when motion is stopped, one or more reference values associated with the position or state of the end effector may be stored for later reference and use. For example, where physical constraints are used to detect engagement, the index value, rotation count, etc. of the motor may be stored at this time and later used to reposition the end effector at or near the physical constraints. The physical constraints may be, for example, maximum cable length, casing wall, maximum range of motion, etc. Further, to prevent over-tensioning of the cable in the event that the cable drives the tool, the movement of the drive disk may be stopped, or the motor stopped simultaneously or near simultaneously in response to the detection performed at block 558.

Once engagement of all the relevant driver discs (those corresponding to the use of the tool discs for a particular surgical tool) has been detected in process block 567 (where the process described above in blocks 554-556-558-564-566 may have been performed for each respective driver disc), a notification of tool engagement is then generated (process block 568). The notification may be a visual notification (e.g., a graphical user interface notification), an audible notification (e.g., a tone, a sound, etc.), a sensory notification (e.g., a haptic notification), or a combination of such notifications generated by user interface hardware of the surgical robotic system.

Returning briefly to process block 558, when the engagement condition is not met (e.g., the monitored motor operating parameter does not meet the threshold such that the tool disk and corresponding drive disk have not mechanically engaged), it is determined whether a time or rotation limit has been reached (process block 560). (the engagement failure may be due to a cable break, the tool tray and the drive tray not being close enough to be positioned in engagement with each other, etc.) the time limit may be a predetermined maximum time interval (countdown timer value) in which the drive tray is allowed to rotate without detecting mechanical engagement with the tool tray. Similarly, the rotation limit may be the number of motor rotations required to impart one or more full rotations of its respective drive disk. For example, if the rotation limit is associated with one full rotation of the drive disc, it is assumed that the engagement should occur within a single rotation of the drive disc. If the time limit, rotation limit, or some combination of limits have not been reached (process block 560), then one or more motor operating parameter values continue to be monitored (returning to process block 556), however, if one or more limits have been reached (process block 560), then a notification is generated that an error has occurred and that tool engagement has failed (process block 562), which is similar to the notification of process block 568. In such a case, the operator of the surgical system may be instructed to detach the surgical tools from the tool driver and then reattach them to restart the engagement process of fig. 5B.

Turning now to fig. 5C, this is a diagram of a process performed by the control unit for engaging a surgical robotic tool with a tool driver as part of a surgical robotic system. The system includes a surgical robotic tool 240 as shown in fig. 2 having one or more tool trays at a proximal end and an end effector at a distal end thereof. A tool driver (e.g., tool driver 230) is mounted at the distal end of the surgical robotic arm 220, as shown, wherein the tool driver 230 has one or more drive disks 234, each driven by a rotary motor within the housing of the tool driver. Each drive disk 234 is attached to a tool disk 244 of the surgical tool 240 to impart motion to an end effector 246.

Still referring to fig. 5C, the process for engaging the tool tray with the drive tray is performed by the control unit, in particular by one or more processors of the control unit configured (or programmed) to perform the process. Operations may begin by detecting attachment of a surgical tool to a tool driver (block 582); this may be done by the processor reading, wirelessly or via a wired connection, identification information or other attributes of the tool that has been in contact with the tool drive such that the tool disk is in contact with the corresponding or respective drive disk. The control unit may then actuate each drive disk by means of the rotary motor (block 584), and detect engagement of the drive disk with the corresponding tool disk during actuation (block 586); the drive plate is said to engage the tool plate when a pair of coupling features of the drive plate interlock with the tool plate (there may be more than one pair, e.g., two pairs, as shown in fig. 4A-4C). To detect engagement, the control unit identifies a sensed change in motor state (state of the actuator or motor operating parameters thereof), including a drop in speed of the rotary motor below a predetermined speed threshold and a rise in torque of the rotary motor above a predetermined torque threshold. The speed threshold may correspond to a speed at which the motor substantially stops, wherein the torque threshold is a value between: i) a minimum torque of the motor to overcome friction between the drive plate and the tool plate prior to engagement, and ii) a maximum torque generated by the motor. The change in the state of the motor may be caused by at least one of: an end effector reach joint limit, an external force on the end effector, a motion constraint due to activation of another motor of the tool driver, and combinations thereof. Depending on the particular surgical tool, there may be more than one tool tray used to operate the end effector. In this case, the above-described engagement process is also performed for each additional tool disk (with a corresponding drive disk in the tool drive). The process then continues to block 588 where the control unit signals, for example, a user interface subsystem of the surgical robotic system to report engagement of the surgical tool, but only if all of the tool trays for the particular tool have been detected as being engaged with their respective drive trays.

In one embodiment, a feedback loop may be used to monitor one or more motor operating parameters and detect when a threshold has been reached. Fig. 6 shows a block diagram of a feedback loop for controlling the speed of a motor of a tool drive using speed feedback. The feedback loop may be implemented in hardware, firmware, software, or a combination thereof. The controller 602 receives a speed command. The controller 602 may be, for example, a proportional-integral-derivative controller (e.g., PID controller 702 of fig. 7) that provides a loop/feedback mechanism to provide an appropriate motor current (e.g., controller output, ctrl output) for driving the motor/actuator 604 at that speed and in the direction of the speed command (also referred to as a speed set point). For example, the direction may be in the direction of winding of the cable driven tool reel 244-j. As another example, the direction may be the direction that would be opposite to the direction of motion of another motor to which the tool plate 244-i attached should mate with the tool plate 244-j. As another example, the direction can be a direction that causes the motor to advance the end effector toward a hard stop (e.g., a physical barrier or a mechanical limit to the range of motion). In one embodiment, the controller 602 may use various values, such as a desired torque to achieve speed, a current to achieve speed, an impedance indicative of speed, etc., as a measure of the current used to generate the controller output to the motor/actuator 604.

A sensor (e.g., a torque sensor, a speed sensor, or a combination of sensors) measures the actual speed of the motor/actuator. The actual speed is then returned as feedback to the controller 602, which may calculate an error based on the difference between the actual speed of the motor and the commanded speed. The controller 602 responds to the difference by adjusting its controller output, e.g., a motor current command to the motor/actuator 604, a torque implemented by the motor/actuator 604, an impedance value, etc., which will move the motor/actuator 604 toward a speed command or set point. In some embodiments, the controller 602 may output motor operating parameters such as torque, current, impedance, speed, etc. calculated as a result of executing a feedback loop.

In another embodiment, the controller 602 may include a saturation module (not shown) to ensure that the controller output (e.g., the value of the control motor current) does not exceed a threshold, such as a current threshold, a torque threshold, an impedance threshold. The values used by or input to the saturation module may be dual-purpose, i.e., also used as motor operating parameter values provided to the processor (in order to be monitored during the engagement process).

Fig. 7 shows a block diagram of a feedback loop including a controller 702 for controlling the speed of the motor of the tool driver. In one embodiment, the controller 702 is a proportional-integral (PI) controller and may be used in the controller 602, which may be partially implemented as hardware, firmware, software, or a combination thereof.

The controller 702 receives a speed command (e.g., controls a variable set point). The controller 702 provides a loop/feedback mechanism to regulate and provide the appropriate current (e.g., controller output) to drive the motor/actuator 704 at that speed and in the speed command/set point direction. For example, the direction may be in the winding direction of a tool reel of a cable driven surgical tool. As another example, the direction may be a direction that would be opposite to the motion of another motor of the tool drive. As another example, the direction can be a direction that causes the motor to advance the end effector toward a hard stop (e.g., a physical obstruction or a mechanical limit of range of motion). In one embodiment, the controller 702 may use various values, such as a desired torque to achieve speed, a current to achieve speed, an impedance to indicate speed, etc., as a measure of the controller's current used to generate the output to the motor/actuator 704.

Adjustments are made to the raw speed command, such as proportional adjustments (e.g., module k) _p ): adjust the speed in proportion to the error (e.g., as determined by feedback); and integral adjustment (e.g., module k) _i ): the speed is adjusted taking into account the integral of the past error over time. Use can be made of a module k located in a feedback loop for anti-wrap _b The generated recovery term is used to further adjust the integral adjustment to further adjust the value of the integral adjustment. The integral adjustment value may also be adjusted by module 1/s (e.g., before adding to the proportional set adjustment value; in one embodiment, as shown, a saturation module may be used in the controller 702 to ensure that the value of the current provided to the motor does not exceed a threshold, e.g., a current threshold, a torque threshold, an impedance threshold, etc.. after adjusting through the blocks discussed above and the resulting current command value does not exceed the value set in the saturation block, a current command (e.g., an adjusted command that has been corrected based on feedback and PI adjustments) is fed into a current amplifier so that the commanded current into the motor/actuator 704 may be amplified by a factor. And will provide feedback responsive to the speed of the motor/actuator 704 (e.g., as determined by sensors coupled to the motor)Constant speed, torque, speed, etc.) is provided to a feedback loop implemented by the controller 702, as shown.

As described above, the value used by (or input to) the saturation module may be used as a motor operating parameter value provided to the processor for monitoring, e.g., displaying, a present motor current or a present motor impedance during the engagement process.

In another embodiment, feedback may be used as a motor operating parameter value provided to the processor for monitoring during the engagement process. Other variables (e.g., adjusted and unadjusted) calculated in the controller 702 may be used as monitored motor operating parameters.

In one embodiment described above, the two actuators share a load when moving the surgical tool, for example sharing a load to rotate the endoscope. A surgical tool (e.g., an endoscope) may have a rotary joint without an encoder, and thus position is determined according to the angle of the motor or actuator. Without engagement, the angle of rotation of the surgical tool cannot be determined. There are no mechanical hard stops on the swivel joint and therefore hard stops may not be used for homing. The rotary joint is coupled to two motors on the tool drive. In normal operation, the two motors work in concert to drive the rotary joint. For example, in remote operation after engagement and homing, one motor is the primary motor and is controlled in position mode, and the other motor is the secondary motor and is controlled in position mode or current (torque) mode. Both motors drive movement of the surgical tool in the same direction. The motors must engage the rotary union before both motors drive the endoscope rotary union, and the endoscope engagement angle is calculated (i.e., nested) based on the motor union position when engagement is complete.

Fig. 2 illustrates an exemplary surgical robotic system for motor-controlled engagement and/or homing in the surgical robotic system. Typically, two or more drive disks 234 are engaged with corresponding two or more tool pads or disks 244. The pad may have other shapes than a disc, such as a plus ("+") shape. Examples herein use disks.

The surgical tool 240 is a surgical tool, such as any of the surgical tools used in medicine or discussed herein. In one embodiment, the surgical tool 240 is an endoscope. Rather than having scissors, jaws, or other tools, the surgical tool 240 has a camera at the distal end as an end effector 246. The endoscope shaft can be rotated 360 degrees without hard stops. There may be any number of rotations, as there are no hard stops or physical limits to the rotation. Other tools for rotation or other movement may be used.

Robotic surgical tool 240 includes a housing, a shaft, and an end effector 246 from a proximal end to a distal end. A tool plate 244 is positioned in the housing and linked to an end effector 246 (e.g., via a cable, rod, and/or other transmission), which is driven by the drive plate 234 via the tool plate 244 and, upon proper engagement, transmits.

A rotary tool disk 244 is connected to the shaft of the surgical tool 240 for rotating the surgical tool 240. Two or more rotary tool trays 244 are connected by a transmission to link the tool trays 244 to the surgical tools 240. Gears, clutches, cables, belts, and/or other linkages receive forces, such as rotational forces, from two or more tool disks 244 to rotate the surgical tool 240. Sharing power for rotating the surgical tool. In one embodiment, both tool disks 244 rotating in the same direction help to rotate the surgical tool 240 in the same or opposite directions. In another embodiment, the transmission link causes two tool disks 244 that rotate in opposite directions to rotate the surgical tool 240 in one of the directions.

The tool driver 230 includes an actuator 238 (e.g., a motor) connected directly or through a transmission to the drive disk 234. The actuator 238 and the drive disk 234 form a rotary motor drive that can mate with the tool disk 244 (e.g., engage the coupling features 447 and 448). The drive disk 234 mates with a tool disk 244. Engagement or mating occurs once the surgical tool 240 is connected to the tool driver 230.

The sensor 236 is one or more different sensors. For example, the sensor 236 is an encoder for detecting the position (such as angular position) of the motor shaft and/or drive plate 234. The encoder may output position information so that the processor may determine the speed from the time derivative of the position. As another example, the sensor 236 is a current sensor (e.g., a current sense resistor in series with the motor input drive terminal) for detecting the magnitude of current provided to and/or emitted by the actuator 238. Additional, different, or fewer sensors 236 may be provided for each actuator 238, such as providing current sensors and encoders.

As shown in fig. 9, a current source 901 may be provided. The current source 901 outputs a current to the actuator 238. Based on the control signal, the current source 901 provides current to move the actuator 238 in a position mode, a torque (e.g., current) mode, or other control mode. The actuator 238 is powered to cause rotation, causing it to rotate to a given angular position (position mode) or move at a given speed (e.g., current mode). Other control modes may be used.

In one embodiment as shown in fig. 9, a current source 901 adds a dither current 902, such as a high frequency (e.g., 60Hz or higher (e.g., 100Hz)) sinusoidal current. The dither current 902 is of low magnitude, e.g., 10% or less of the maximum current 908. The dither current 902 is added to the ramp current 900 provided to the actuator 238. The dither current 902 is added at the initial portion of the ramp up current and removed to complete the ramp up. In other embodiments, the dither current 902 is added in other ranges, such as after the ramp current is initiated and/or removed after the steady state current 904 is reached. The dithering current 902 may help reduce static friction during contact between the tool disk 244 and the drive disk 234 for engagement.

The processor 312 of the control unit 210 is configured to detect the engagement of the rotary tool disc 244 with a corresponding rotary drive (e.g., the rotary drive disc 234) by a change in the signal. Engagement of the drive disk 234 with the tool disk 244 is detected. The drive disk 234, under power from the motor or actuator 238, may slide relative to the tool disk 244 until engaged, at which time the tool disk 244 and the drive disk 234 rotate together.

The processor 312 is configured to detect the mating based on a change in the signal or property from the actuator 238. Signals from sensor 236, such as current and/or speed, are used to detect engagement. Upon engagement, the signal changes. For example, the speed drops to zero or below a threshold speed. As another example, a current spike rises or exceeds a threshold current. As another example, both low speed and current spikes are detected as indicative of engagement or mating.

Since two or more actuators 238 drive the surgical tool 240 in combination, the change in the signal for detecting engagement can be performed for both motor drivers. For example, the current and/or speed of each actuator 238 is monitored to detect engagement. The engagement of each actuator 238 with the surgical tool 240 is detected.

Where no hard stops are provided, the actuators 238 may be driven in opposition to each other. The motor drives may attempt to rotate the surgical tool 240 in opposite directions and/or at different speeds, which are opposite to each other rather than attempting to rotate together. Each actuator 238 is used to drive a surgical tool 240. By operating opposite of each other, the actuator 238 may attempt to rotate the surgical tool 240 in the opposite direction and/or at different speeds. The driving is done in a position control mode, but a current control mode or other modes may be used.

The signal to the actuator or drive motor may not vary greatly when the initial drive disk 234 is mated with the corresponding tool disk 244 because this initial drive disk 234 is the only driver that rotates the tool. The current and/or speed may vary due to the resistance of the rotating surgical tool 240, but the speed may not vary below a speed threshold and/or the current may not spike above a current threshold. Once the other or subsequent drive disk 235 is mated with the corresponding tool disk 244, both motor drivers are engaged and attempt to rotate the surgical tool 240 in opposite directions and/or at different speeds. Thus, the speed of the two motors drops below a threshold and/or the current of the two motors spikes. The motor drives oppose each other and act as a mutual hard or soft stop. If the motors have the same strength or power and rotate at the same speed, opposite each other, the speed drops to zero and the current spikes to a maximum. In the case of motors with different power due to design or tolerances and/or different speeds, larger speeds and/or smaller current spikes may be provided while still being below the speed threshold and/or above the current threshold, respectively.

The processor 312 is configured to verify engagement. After the mating is detected, the engagement may be verified. Once engaged, the encoder indicates the rotational position of the tool disk 244. Since the tool disks 244 are linked to the same surgical tool 240, the tool disks have a known relative rotation with respect to each other. For example, the tool tray 244 is designed to have the same angle as any given rotational position of the surgical tool 240, but opposite sign. In other examples, any relative combination of angles may be used. Due to the engagement, the position of the driving disc 234 corresponds to the position of the tool disc 244. In the case where the engagement angle matches the design angle, the engagement is verified.

The processor 312 is configured to primitive the rotation angle of the surgical tool 240. Once engaged, the current angle of rotation of the surgical tool 240 is determined. The surgical tool 240 is calibrated such that the angle of the rotating tool disk 244 for each angle of rotation of the surgical tool 240 is known. Upon engagement, the processor 312 determines the angle of rotation of the surgical tool based on the angle of rotation of the engaged rotary drive (e.g., actuator 238, drive disc 234, and/or tool disc 244). Calibration relates the angle of the engaged rotary drive to the angle of the surgical tool 240. Referring to fig. 8, upon completion of the engagement, the joint (e.g., tool tray) angles are α 1 and α 2, respectively, when the surgical tool (e.g., endoscope) is in the original (zero) position θ T. Both α 1 and α 2 are pre-calibrated and measured from the encoder-based angles θ 1 and θ 2 of the two motors M1, M2.

Fig. 8 and 9 illustrate another embodiment of detecting engagement of two motor drivers for controlling the same movement of a surgical tool 240. A combination of position control mode and current control mode is used to detect the coordination of changes from the signal.

The equation of motion of the motion after engagement can be expressed as:

θ ═ γ, (θ 1-a1) θ 1- α 1 ═ θ 2- α 2) where θ, θ 1, θ 2-the angle of engagement of the endoscope, motor M1 joint, motor M2 joint γ -gear ratio α 1, a 2-the angle of M1, M2 joint at zero position of the endoscope

This equation of motion can be used for joint detection and/or homing.

In a first step, the motor M2 is set to operate in a position control mode. The target position is set as the current position, and therefore the motor M2 remains stable or at the current position.

In a second step, motor M1 is set to operate in current control mode. As shown in fig. 9, current 900 ramps up until the speed reaches a threshold, represented by the horizontal portion 904 of current 900. The maximum current 908 and the offset of the ramp slope for the horizontal portion 904 may be determined experimentally.

A dither current 902 is added to the current 900. For example, a high frequency (e.g., 100Hz) sinusoidal current provides low amplitude jitter and is superimposed on the ramp current. This high frequency current helps overcome static friction between

disks

234, 244. The angular velocity 906 of the actuator 238 and drive disk 234 ramps up and then stabilizes based on this current control. The direction of the current command (i.e., the direction of rotation) is arbitrary. The maximum current limit 908 is set between a maximum current for driving the motor alone and a minimum current for driving the coupled motor and endoscope. This limit can be determined experimentally.

During this second step, the engagement of the motor M1 is detected. The engage-current command ramp up to maximum current is detected with motor M1 never moving. This may occur with the tool plate 244 engaged with the drive plate 234 when the contacts are connected or placed. Before reaching the desired speed or after reaching the desired speed, engagement is detected with the motor M1 stopped. If the motor M1 does not stop after a full rotation is detected by the encoder, the speed limit may be decreased (e.g., to a value that is less than the speed limit)

) And the second step is repeated. If the second step fails to detect engagement again, an error is reported and the process is stopped.

In the third step, the motor M1 is set to the position mode, and the target position is set to the current position θ 1 to hold the motor M1 in the home position. In the fourth step, the motor M2 is set to the current control mode. The same current profile used in the second step was used (see fig. 9). The direction of rotation of the current is set to be shorter toward- (θ 1- α 1) + α 2. The same speed and/or motion conditions are used to determine if motor M2 is engaged.

In the second step and the fourth step, the engaged state may be detected using the speed change instead of the check stop. Once engagement is confirmed, the current command is set to zero and the next step is followed.

The current ramp-up control in the second and fourth steps may be replaced with a speed closed loop control with current saturation. In the second step, the motor M1 is set to the speed control mode, and the target speed is set to a predetermined value. The direction of the speed is arbitrarily chosen. The engaged state is detected in the case where the motor M1 is stopped or there is a sudden jump in the motor current measurement. In the fourth step, the motor M2 is set to the speed control mode, and the target speed is set to a predetermined value. The direction of the velocity is a direction at a shorter distance from- (θ 1- α 1) + α 2.

In the fifth step, the motor M1 is kept in the position control mode, and the motor M2 is kept in the current control mode. The engagement angles of the motors M1 and M2 are checked to verify that the equation of motion is satisfied. In the case where the angle matches the design angle, complete engagement is confirmed. If the splice fails twice in succession and/or if the splice fails to be verified, the splicing process can be stopped and an error reported.

After successful engagement, homing can be determined. The endoscope engagement angle relative to the zero position can be calculated from the motor M1 engagement angle using the equation of motion.

Fig. 10 illustrates one embodiment of a method for engaging motor control of a surgical tool in a surgical robotic system. The method also includes homing the rotational position of the surgical tool in the surgical robotic system. For example, engagement and/or homing of the endoscope with the tool driver motor (M1, M2) is provided. The drive motor is engaged until the motor joint shaft is securely coupled with the endoscope shaft by a key and/or a key hole or another coupling. Homing finds the engagement angle between the zero position of the endoscope rotary joint and the main joint encoder position.

The method is performed by the surgical robotic system of fig. 2 and 3 or another surgical robotic system. The method is performed with the same motion of the two motors driving the surgical tool, such as by rotation of the endoscope in the same direction. The processor of the control unit or other controller performs the method when connecting the surgical tool 240 to the tool driver 230. Once the identification information of the surgical tool 240 is determined to be a tool with two or more motors that combine their power or motion to drive the same movement, the processor performs engagement detection and/or homing.

The actions are performed in the order shown or a different order. For example, act 1002 and act 1004 are performed concurrently. As another example, acts 1002 and 1004 are repeated to detect engagement of different motors. Additional, different, or fewer acts may be provided. For example, act 1006 and/or act 1008 are not provided for detecting engagement. As another example, where other engagement detections are used,

acts

1002 and 1004 are not provided. As another example, act 1006 is not provided. In other examples, actions for remote operation or surgical use of an endoscope or another surgical tool that engages and nests are provided. In one embodiment, attachment of the surgical tool to the tool driver is detected (see act 552 of fig. 5B and act 582 of fig. 5C) to later trigger engagement of the detection plate.

In act 1000, a processor (e.g., a controller or control unit) detects engagement of two or more rotary tool pads or disks 244 with respective two or more rotary drives (e.g., actuator 238 and drive pad or disk 234). The drive disk 234 engages the tool disk 244 using a releasable (e.g., spring-loaded, physical barrier, or friction fit) engagement.

In act 1002, a motor (e.g., actuator 238) is rotated. The rotation of the motor is performed under position control, but other control modes may be used. During teleoperation, to rotate or translate the surgical tool in one direction, both motors rotate in a particular direction (e.g., both motors rotate in the same direction, or one motor rotates in one direction while the other rotates in a different direction), which relies on a transmission or other linkage from the tool tray 244 to the surgical tool 240. For engagement, the motors rotate opposite to each other. For example, the endoscope is rotated clockwise by rotating one motor clockwise and the other motor counterclockwise. To rotate opposite to each other, the motors rotate in the same direction, such that one motor attempts to rotate the endoscope clockwise and the other motor attempts to rotate the endoscope counterclockwise. Since the endoscope does not have a hard stop or physical limiter for rotation, the opposite rotations of the motors sharing the burden of movement oppose each other, acting as a stop once engaged.

As the motor rotates, a drive disk 234 connected to the motor rotates either directly or through a gear. The drive disk 234 is in frictional contact with the tool disk 244. The rotation has sufficient force to overcome the static friction, and thus the drive disk 234 rotates relative to a tool disk 244 that is linked to a surgical tool (e.g., surgical tool 240 or an endoscope). Rotation should ultimately result in engagement of the physical engagement mechanisms on the tool (e.g., tabs and recesses, shaped extensions and slots, tabs and stops, and/or snap-fit engagement retainers and extensions) with the

drive discs

234, 244.

Dithering of the current control mode, the position control mode, and/or other control modes may be used. By dithering the command signal, static friction may be more easily overcome such that the drive disk 234 rotates at a greater rate of speed for engagement than the tool disk 244.

Once two or more pairs of tool discs 244 and drive discs 234 are mated or engaged, the opposite rotation acts as a stop. Once engaged, rotational force from each motor is transmitted through a linkage or transmission connected to the tool plate 234, resulting in resistance to movement.

In an alternative embodiment, one of the motors is controlled in position mode to not rotate while the other motor rotates to engage. Once one motor is engaged, the engaged motor drive does not rotate while the other motor is engaged. For example, the steps shown in fig. 9 above are performed.

In act 1004, a processor (e.g., a control unit or controller) monitors and detects engagement of a motor (e.g., actuator 238) with a respective tool tray 244. Detection is based on monitoring a change in performance of the motor. The change may be expressed as a difference, such as a difference in performance above a threshold (e.g., current doubled or increased by more than X times). The change may be expressed as an absolute value relative to a threshold, such as a speed transition below a threshold speed (e.g., a speed transition to zero) and/or a current transition above a threshold (e.g., a current spike).

Engagement is detected upon a performance change in one or more parameters (e.g., both current and speed) of each of the motors. Engagement may be detected as engagement of all or a subset of the motors. Engagement of the surgical tool is detected upon a change in a performance characteristic of each of the motors or each of the motor sub-groups. Alternatively, engagement is detected separately for each motor. Once all required motors are engaged, the engagement process is ended.

In act 1006, a processor (e.g., a controller or control unit) checks or verifies the engagement. Once engagement is detected, a check is performed to verify that engagement is good. The check relies on a transmission or linkage between the tool tray 244 and the surgical tool 240. Since both tool disks 244 drive the same motion, the angle of the tool disks 244 relative to each other is fixed or within a tolerance. The means for engaging has a fixed orientation on the tool plate 244 and the drive plate 234, and thus the engaged tool plate 244 has that fixed orientation with the two engaged. The angle of the drive discs 234 and corresponding motor shafts are measured by a sensor 236 (e.g., an encoder). Due to the engagement, the angle corresponds to the angle of the tool tray 244.

The rotation angles are compared. Engagement is verified in the event that an expected or rotational angle within a threshold is detected. For example, the gearing or linkages between the tool trays 244 are designed to have the same angle as any rotational position of the surgical tool 240 (e.g., endoscope), but opposite signs. Once engaged, the rotational positions of the motor and drive disk 234 are at the same angle (e.g., the same absolute angle, different in sign). Other combinations of angles may be used.

In act 1008, a processor (e.g., a controller or control unit) determines a current angle of rotation of the surgical tool once engaged. This homing determines the angle of rotation of the medical instrument when engaged.

The angle of rotation is determined by the motor angle and the angle of the corresponding drive disk 234. Once engaged, the angle of the drive disk 234 to the sensor 236 is the angle of the tool disk 244. A look-up table or other function from the calibration maps the angle of the tool disk 244 (and/or the drive disk 234) to the angle of the surgical tool. The transmission correlates the tool tray 244 angle to the surgical tool angle or position and the calibration measures the relationship. Once the angle of the

disks

234, 244 for each motor drive is determined, calibration is used to find the angle of the surgical tool 240.

The splicing and/or homing process then ends. If no splice is detected in act 1000, then no splice is verified in the check of act 1006, and/or the homing of act 1008 fails, the process for splicing is repeated or a different splicing process may be performed. If multiple failures occur, an error message is sent. In the event of successful performance of the engagement and/or homing, the surgical tool 240 and motor driver are ready for remote operation during surgery.

The above description of illustrated embodiments of the invention, including what is described below in the abstract of the specification, is not intended to be exhaustive or to limit the invention to the precise forms disclosed. While specific embodiments of, and examples for, the invention are described herein for illustrative purposes, various modifications are possible within the scope of the invention, as those skilled in the relevant art will recognize. For example, while fig. 4A-4C illustrate a surgical tool 240 having a cable-driven transmission connecting the tool tray 244 to an end effector (not shown), the engagement process described above is also applicable to other types of surgical tools having different transmissions (not necessarily cable-driven). These modifications can be made to the invention in light of the above detailed description. The terms used in the following claims should not be construed to limit the invention to the specific embodiments disclosed in the specification. Rather, the scope of the invention is to be determined entirely by the following claims, which are to be construed in accordance with established doctrines of claim interpretation.

Claims

1. A method for tool engagement in a surgical robotic system, the method comprising:

detecting a mechanical attachment of a surgical tool to a tool driver, the tool having first and second tool disks engaged with first and second drive disks, respectively, of the tool driver, the first and second tool disks linked to an end effector of the surgical tool;

actuating the first drive disk by a first motor of the tool drive and actuating the second drive disk by a second motor of the tool drive such that the first drive disk and the second drive disk rotate in opposition to each other;

monitoring the performance of the first motor and the second motor; and

detecting engagement of the first and second tool discs with the first and second drive discs based on the change in performance of the first and second motors.

2. The method of claim 1, wherein actuating comprises actuating the first motor and the second motor in a position control mode.

3. The method of claim 1, wherein actuating the first and second drive disks comprises actuating the first and second motors in the same direction, wherein a link between the first and second tool disks and the surgical tool utilizes rotation of the first and second tool disks in opposite directions to rotate the surgical tool in the same direction.

4. The method of claim 1, wherein the movement of the surgical tool comprises rotation of an endoscope without a hard stop.

5. The method of claim 1, wherein detecting comprises detecting a current spike of the first motor and the second motor.

6. The method of claim 1, wherein detecting comprises detecting a first speed and a second speed below a speed threshold of the first motor and the second motor, respectively.

7. The method of claim 1, further comprising checking that a first angle of rotation of the first tool tray at the time of the engaging is within a threshold amount, wherein the first angle of rotation has an opposite sign at the time of the engaging as a second angle of rotation of the second tool tray.

8. The method of claim 1, further comprising determining a rotation angle of the surgical tool when engaged as a function of first and second angles of the first and second motors when the surgical tool is engaged with the first and second tool trays.

9. The method of claim 8, wherein determining comprises determining the angle of rotation based on calibration.

10. A surgical robotic system for engagement, the system comprising:

a surgical effector connected to first and second rotary tool pads by a transmission, the surgical effector connected such that rotation of the first and second rotary tool pads rotates the surgical effector;

a tool driver having first and second rotary drivers cooperable with the first and second rotary tool pads, respectively; and

a processor configured to detect the mating of the first and second rotary tool pads with the first and second rotary drivers, respectively, through a change in a signal.

11. The surgical robotic system of claim 10, wherein the surgical implement comprises an endoscope rotatable about a longitudinal axis.

12. The surgical robotic system of claim 10, wherein the processor is configured to detect the engagement, wherein the first rotary tool pad is driven by the first rotary driver to rotate the surgical implement in an opposite direction from the second rotary tool pad driven by the second rotary driver.

13. The surgical robotic system of claim 12, wherein the processor is configured to drive both the first rotary drive and the second rotary drive in a position control mode.

14. The surgical robotic system according to claim 10, further comprising first and second encoders connected with the first and second rotary drives, the processor configured to detect a change in the signal when first and second speeds of information from the first and second encoders are within a threshold amount of zero.

15. The surgical robotic system according to claim 10, further comprising a current sensor connected to detect a current of the first and second rotary drivers, the processor configured to detect a change in the signal when the first and second currents of the first and second rotary drivers spike.

16. The surgical robotic system of claim 10, wherein the processor is configured to verify the fit by comparing a first angle of rotation of the first rotary driver to a second angle of rotation of the second rotary driver.

17. The surgical robotic system of claim 10, wherein the processor is configured to determine the angle of rotation of the surgical implement based on the angles of rotation of the first and second rotary drivers when mated with the first and second rotary tool pads.

18. The surgical robotic system according to claim 10, further comprising a current source configured to apply a dithering current to the current ramp in a current control mode of a first rotary driver, wherein the processor is configured to detect the engagement according to the change in the signal from the first rotary driver in the current control mode.

19. A method for homing a rotational position of a surgical tool in a surgical robotic system, the method comprising:

detecting engagement of the first and second rotary tool pads with the first and second rotary drivers; and

determining a rotation angle of the surgical tool linked to the first and second rotary tool pads, the rotation angle of the surgical tool determined from first and second rotation angles of the first and second rotary drivers upon detection of the engagement.

20. The method of claim 19, wherein determining comprises determining the angle of rotation of the surgical tool based on a calibration and the measured angle of rotation from a motor encoder sensor.

21. The method of claim 19, wherein detecting the engagement comprises rotating the first and second rotary drivers in contact with the first and second rotary tool pads, respectively, both linked to the surgical tool, the first and second rotary drivers rotating such that the first and second rotary tool pads rotate opposite each other to rotate the surgical tool, and detecting the engagement of the first and second rotary drivers with the first and second rotary tool pads, respectively, as a function of a change in performance of the first and second rotary drivers.