Surgical robotic systems and methods for automatic grip force adjustment during suturing

Abstract

A surgical robotic system includes a robotic arm having an instrument having a pair of opposing jaws configured for grasping and an instrument drive unit configured to couple to and actuate the instrument. The system also includes a surgeon console having a handle controller configured to control the robotic arm and the instrument. The system further includes a controller configured to: receive electrical characteristics of the opposing jaws; receiving an angle of the opposing jaws; determining whether the opposite clamping jaws grasp the metal object or not; and adjusting the gripping force of the opposing jaws based on the determination.

Description

Background Art

[0001] Surgical robotic systems are currently used for a variety of surgical procedures, including minimally invasive medical procedures. Some surgical robotic systems include a surgeon's console that controls a surgical robotic arm and a surgical instrument having an end effector (e.g., a clamp or grasping instrument) coupled to and actuated by the robotic arm. In operation, the robotic arm moves to a position above the patient and then guides the surgical instrument into a small incision via a surgical port or natural orifice in the patient to position the end effector at a working site within the patient's body.

[0002] The popularity of robotic-assisted wristed instruments has led to the use of suture-based repairs in minimally invasive surgery. Sutures are commonly used to close abdominal wall defects in hernia procedures, attach hernia patches to adjacent tissue without the use of staples, perform hand-sewn anastomoses, close enterotomies, etc.

[0003] Current robotic systems do not have the ability to fully replicate the suturing experience in an open surgical setting. Surgeons lack adequate tactile feedback, an important factor for manipulating delicate structures. Surgeons rely solely on visual cues to determine sensory inputs, such as tissue compression and suture tension. These visual cues are often traceable indicators of tissue damage, which can lead to ischemia, necrosis, and in some cases, inflammation and adhesions.

[0004] Robotic system manufacturers are aware of this teleoperation problem and have begun integrating sound or vibration alert features triggered by machine measurements into their products. While a step in the right direction, this increases the cognitive load required of surgeons. They need to first sense the feedback (e.g., tactile vibration), then interpret it, and finally respond. In the time between when the stimulus occurs and when the surgeon responds, the suture or tissue may have been damaged.

[0005] Currently, robotic systems do not offer herniorrhaphy or advanced anastomotic suturing solutions, and the training they provide to customers typically uses suturing as the preferred approach. Further, robotic systems do not prevent surgeons from applying excessive loads to objects found within the jaws of the instrument. Surgeons typically clamp synthetic hernia patches or sutures, which can create compressive yield stresses on the polymer, creating stress concentrations in the finished surgical product, which can become a point of failure in the future. Therefore, there is a need for improved suturing in surgical robotic systems. Summary of the invention

[0006] In robotic assisted surgery (RAS), suturing is considered a core skill that surgeons need to master, and therefore surgeons need to spend a lot of time to perfect their RAS suturing techniques. Due to the challenges faced by surgeons when exchanging instruments, it is common to see surgeons use a single needle driver in their dominant hand and a grasper (e.g., a bipolar grasper with holes) in the other hand. Therefore, instruments that are not designed to hold and drive needles are often used for this purpose.

[0007] The present disclosure provides a gripper (e.g., a needle driver) having electrically sensed and isolated jaws. An insulating material or housing separates the tissue contact surface from the rest of the instrument and the jaws. The insulating material can be formed of a dielectric polymer, ceramic, or composite material that forms a non-conductive barrier between the relative jaws of the gripper. The gripper can be used with a surgical robotic system and actuated by an instrument drive unit supported on a robotic arm. The surgical robotic system can also include an impedance sensing device having a power source configured to measure electrical properties of the jaws, such as continuity, conductivity, and / or impedance. The robotic system uses the electrical properties together with the jaw angle (i.e., percentage of opening) to characterize an object grasped by the gripper. The robotic system includes a controller configured to execute software instructions implementing an algorithm for determining whether the gripper's jaws grasp a needle, and adjust the grasping force accordingly.

[0008] According to one embodiment of the present disclosure, a surgical robot system is disclosed. The surgical robot system includes a robotic arm having an instrument and an instrument drive unit, the instrument having a pair of opposing jaws configured for grasping, and the instrument drive unit is configured to be connected to the instrument and actuate the instrument. The system also includes a surgeon's console having a handle controller configured to control the robotic arm and the instrument. The system further includes a controller configured to: receive electrical characteristics of the opposing jaws, receive an angle of the opposing jaws, determine whether the opposing jaws grasp a metal object, and adjust the gripping force of the opposing jaws based on the determination.

[0009] The implementation of the above embodiment may include one or more of the following features. According to one aspect of the above embodiment, the surgical robot system may further include an electrical sensor configured to measure electrical characteristics. The electrical characteristic may be impedance. When determining whether the relative jaws grasp a metal object, the controller may be further configured to compare the impedance with a threshold impedance corresponding to the metal object. The metal object may be a suture needle. The instrument drive unit may be configured to measure an angle. When determining whether the relative jaws grasp a metal object, the controller may be further configured to compare the measured angle with a threshold angle configured to grasp the needle. The controller may be further configured to determine whether the relative jaws grasp the suture needle, and adjust the gripping force of the relative jaws based on the determination. The controller may be further configured to increase the gripping force in response to determining that the suture needle is grasped. The controller may be further configured to reduce the gripping force in response to determining that the suture needle is not grasped.

[0010] According to another embodiment of the present disclosure, a surgical robot system is disclosed. The surgical robot system includes a mechanical arm having an instrument and an instrument drive unit, the instrument having a pair of relative jaws configured for grasping, and the instrument drive unit is configured to be connected to the instrument. The instrument drive unit includes at least one motor and a sensor, the at least one motor is configured to actuate the relative jaws between the open configuration and the closed configuration, and the sensor is configured to determine the angle between the relative jaws. The system also includes a surgeon's console, the surgeon's console has a handle controller, and the handle controller is configured to control the mechanical arm and the instrument. The system further includes an electrical sensor, which is electrically connected to the pair of relative jaws and is configured to measure the electrical characteristics of at least one of the jaws. The system also includes a controller, which is configured to determine whether the relative jaws grasp the suture needle based on the measured electrical characteristics and the angle of the relative jaws, and adjust the gripping force of the relative jaws based on the determination.

[0011] Implementations of the above embodiments may further include one or more of the following features. According to one aspect of the above embodiments, the measured electrical characteristic may be impedance. When determining whether the relative jaws grasp the suture needle, the controller may be further configured to compare the measured impedance with a threshold impedance corresponding to the suture needle. The sensor may be a motor encoder configured to measure the rotational output of at least one motor. The instrument drive unit may include a drive controller configured to calculate an angle based on the measured rotational output. The controller may be further configured to increase the gripping force in response to determining that the suture needle is grasped. The controller may be further configured to reduce the gripping force in response to determining that the suture needle is not grasped.

[0012] According to another embodiment of the present disclosure, a method for controlling a surgical robot system is disclosed. The method includes measuring the electrical characteristics of the relative jaws of an instrument actuated by an instrument drive unit, the instrument drive unit including a motor. The method also includes measuring the angle of the relative jaws. The method further includes determining at a controller whether the relative jaws grasp a suture needle based on the measured electrical characteristics and the measured angle of the relative jaws. The method further includes adjusting the torque of the motor based on the determination to adjust the gripping force of the relative jaws.

[0013] The implementation of the above embodiment may also include one or more of the following features. According to one aspect of the above embodiment, the method may also include increasing the gripping force in response to determining that the suture needle is gripped. The method may further include reducing the gripping force in response to determining that the suture needle is not gripped. The measured electrical characteristic may be impedance, and the method may further include comparing the measured impedance with a threshold impedance corresponding to the suture needle. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Various embodiments of the present disclosure are described herein with reference to the accompanying drawings, in which:

[0015] Figure 1 is a schematic diagram of a surgical robotic system according to an embodiment of the present disclosure, the surgical robotic system comprising a control tower, a control console, and one or more surgical robotic arms each disposed on a movable cart;

[0016] Figure 2 According to the embodiments of the present disclosure Figure 1 A three-dimensional diagram of a surgical robot arm of a surgical robot system;

[0017] Figure 3 is a perspective view of a mobile cart having a mounting arm according to an embodiment of the present disclosure, the mounting arm having Figure 1 The surgical robot arm of the surgical robot system;

[0018] Figure 4 According to the embodiments of the present disclosure Figure 1 A schematic diagram of the computer architecture of a surgical robot system;

[0019] Figure 5 is positioned around an operating table according to aspects of the present disclosure Figure 1 A schematic plan view of a movable cart;

[0020] Figure 6 is a perspective view of an instrument drive unit and a surgical instrument according to an embodiment of the present disclosure, wherein the components are separated;

[0021] Figure 7According to an embodiment of the present disclosure, Figure 1 A top perspective view of an end effector in a surgical robot system;

[0022] Fig. 8A -C is a side view of the end effector at different angles according to an embodiment of the present disclosure;

[0023] Fig. 9 yes Fig. 8A - A perspective view of the end effector of C with the components disassembled; and

[0024] Fig.10 According to an embodiment of the present disclosure, Figure 1 Flow chart of a method for controlling a surgical robot system. DETAILED DESCRIPTION

[0025] Embodiments of the surgical robotic system disclosed herein are described in detail with reference to the drawings, in which like reference numerals designate like or corresponding elements in each of the several views.

[0026] As will be described in detail below, the present disclosure relates to a surgical robotic system comprising a surgeon's console, a control tower, and one or more movable carts having a surgical robotic arm coupled to a mounting arm. The surgeon's console receives user input via one or more interface devices. The input is processed by the control tower as movement commands for moving the surgical robotic arm and instruments and / or cameras coupled thereto. Thus, the surgeon's console enables remote operation of the surgical arm and attached instruments / cameras. The surgical robotic arm comprises a controller configured to process movement commands and generate torque commands for activating one or more actuators of the robotic arm, which in turn will move the robotic arm in response to the movement commands.

[0027] refer to Figure 1 , the surgical robotic system 10 includes a control tower 20 that is connected to all components of the surgical robotic system 10, including a surgeon's console 30 and one or more mobile carts 60. Each mobile cart 60 includes a robotic arm 40 having a surgical instrument 50 coupled thereto. The robotic arm 40 is also coupled to the mobile cart 60. The robotic system 10 may include any number of mobile carts 60 and / or robotic arms 40.

[0028] The surgical instrument 50 is configured for use during minimally invasive surgical procedures. In an embodiment, the surgical instrument 50 can be configured for open surgical procedures. In another embodiment, the surgical instrument 50 can be an electrosurgical clamp configured to seal tissue by compressing the tissue between the jaw members and applying an electrosurgical current thereto. In yet another embodiment, the surgical instrument 50 can be a surgical stapler comprising a pair of jaws configured to grasp and clamp tissue, simultaneously deploy multiple tissue fasteners (e.g., staples) and cut stapled tissue. In yet another embodiment, the surgical instrument 50 can be a surgical clip applicator comprising a pair of jaws configured to apply a surgical clip to the tissue.

[0029] One of the robotic arms 40 may include an endoscopic camera 51 configured to capture a video of the surgical site. The endoscopic camera 51 may be a stereoscopic endoscope configured to capture two side-by-side (i.e., left and right) images of the surgical site to produce a video stream of the surgical scene. The endoscopic camera 51 is coupled to a video processing device 56, which may be disposed within the control tower 20. The video processing device 56 may be any computing device as described below, which is configured to receive a video feed from the endoscopic camera 51 and output a processed video stream.

[0030] The surgeon console 30 includes a first display 32 that displays a video feed of the surgical site provided by a camera 51 disposed on the robotic arm 40 and a second display 34 that displays a user interface for controlling the surgical robotic system 10. The first display 32 and the second display 34 may be touch screens that allow for the display of various graphical user inputs.

[0031] The surgeon console 30 also includes a plurality of user interface devices, such as a foot pedal 36, and a pair of handle controllers 38a and 38b used by a user to remotely control the robotic arm 40. The surgeon console further includes armrests 33 for supporting the clinician's arms while operating the handle controllers 38a and 38b.

[0032] The control tower 20 includes a display 23 (which may be a touch screen) and outputs on a graphical user interface (GUI). The control tower 20 also serves as an interface between the surgeon console 30 and one or more robotic arms 40. In particular, the control tower 20 is configured to control the robotic arms 40 based on a set of programmable instructions and / or input commands from the surgeon console 30 so as to move the robotic arms 40 and corresponding surgical instruments 50 in such a manner that the robotic arms 40 and surgical instruments 50 perform a desired sequence of movements in response to inputs from the foot pedals 36 and the handle controllers 38a and 38b. The foot pedals 36 may be used to enable and lock the hand controllers 38a and 38b, reposition camera movement, and electrosurgical activation / deactivation. In particular, the foot pedals 36 may be used to perform clutch actions on the hand controllers 38a and 38b. The clutch is activated by pressing one of the foot pedals 36, which disconnects the hand controllers 38a and / or 38b from the robotic arm 40 and the corresponding instrument 50 or camera 51 attached thereto (i.e., prevents movement input). This allows the user to reposition the hand controllers 38a and 38b without moving the robotic arm(s) 40 and instruments 50 and / or camera 51. This is useful when reaching the control boundaries of the surgical space.

[0033] Each of the control tower 20, surgeon console 30 and robotic arm 40 includes a corresponding computer 21, 31, 41. The computers 21, 31, 41 are interconnected to each other using any suitable communication network based on wired or wireless communication protocols. The term "network", whether plural or singular, as used herein, refers to a data network, including but not limited to the Internet, an intranet, a wide area network or a local area network, and is not limited to the full scope of the definition of communication networks covered by the present disclosure. Suitable protocols include but are not limited to the Transmission Control Protocol / Internet Protocol (TCP / IP), the Datagram Protocol / Internet Protocol (UDP / IP) and / or the Datagram Congestion Control Protocol (DCCP). Wireless communication can be achieved through one or more wireless configurations, such as radio frequency, light, Wi-Fi, Bluetooth (an open wireless protocol for exchanging data from fixed and mobile devices over short distances using short-length radio waves), creating a personal area network (PAN), (A set of specifications for advanced communications protocols using small, low-power digital radios based on the IEEE 122.15.4-1203 Wireless Personal Area Network (WPAN) standard).

[0034] Computer 21,31,41 may include any suitable processor (not shown), the processor is operably connected to a memory (not shown), the memory may include one or more of a volatile, non-volatile, magnetic, optical or electrical medium, such as a read-only memory (ROM), a random access memory (RAM), an electrically erasable programmable ROM (EEPROM), a non-volatile RAM (NVRAM) or a flash memory. The processor may be any suitable processor (e.g., a control circuit) suitable for performing the operations, calculations and / or instruction sets described in the present disclosure, including but not limited to a hardware processor, a field programmable gate array (FPGA), a digital signal processor (DSP), a central processing unit (CPU), a microprocessor and combinations thereof. It will be appreciated by those skilled in the art that a processor may be replaced by using any logical processor (e.g., a control circuit) suitable for performing the algorithms, calculations and / or instruction sets described herein.

[0035] refer to Figure 2 , each robotic arm 40 may include a plurality of links 42a, 42b, 42c that are interconnected at joints 44a, 44b, 44c, respectively. Other configurations of links and joints may be used as known to those skilled in the art. Joint 44a is configured to secure the robotic arm 40 to the mobile cart 60 and defines a first longitudinal axis. Figure 3 , the movable cart 60 includes a lift 67 and a mounting arm 61, which provides a base for mounting the robotic arm 40. The lift 67 allows the mounting arm 61 to move vertically. The movable cart 60 also includes a display 69, which is used to display information about the robotic arm 40. In an embodiment, the robotic arm 40 can include any type and / or number of joints.

[0036] The installation arm 61 includes a first link 62a, a second link 62b and a third link 62c, which provide lateral maneuverability of the robot arm 40. The links 62a, 62b, 62c are interconnected at joints 63a and 63b, and each joint may include an actuator (not shown) for rotating the links 62b and 62b relative to each other and relative to the link 62c. In particular, the links 62a, 62b, 62c can move in their corresponding lateral planes parallel to each other, thereby allowing the robot arm 40 to extend relative to the patient (e.g., an operating table). In an embodiment, the robot arm 40 can be connected to an operating table (not shown). The installation arm 61 includes a control device 65, which is used to adjust the movement of the links 62a, 62b, 62c and the elevator 67. In an embodiment, the installation arm 61 can include any type and / or number of joints.

[0037] The third link 62c may include a rotatable base 64 having two degrees of freedom. In particular, the rotatable base 64 includes a first actuator 64a and a second actuator 64b. The first actuator 64a can rotate around a first fixed arm axis perpendicular to the plane defined by the third link 62c, and the second actuator 64b can rotate around a second fixed arm axis transverse to the first fixed arm axis. The first actuator 64a and the second actuator 64b allow the robot 40 to be fully oriented in three dimensions.

[0038] The actuator 48b of the joint 44b is connected to the joint 44c via the belt 45a, and the joint 44c is further connected to the joint 46b via the belt 45b. The joint 44c can include a transfer case connecting the belts 45a and 45b, so that the actuator 48b is configured to rotate each of the links 42b, 42c and the holder 46 relative to each other. More specifically, the links 42b, 42c and the holder 46 are passively connected to the actuator 48b, which is forced to rotate around the pivot point "P", which is located at the intersection of the first axis defined by the link 42a and the second axis defined by the holder 46. In other words, the pivot point "P" is the remote center of motion (RCM) of the robot 40. Therefore, the actuator 48b controls the angle θ between the first axis and the second axis, thereby allowing the surgical instrument 50 to be oriented. Due to the interconnection of the links 42a, 42b, 42c and the retainer 46 via the straps 45a and 45b, the angle between the links 42a, 42b, 42c and the retainer 46 is also adjusted to achieve the desired angle θ. In an embodiment, some or all of the joints 44a, 44b, 44c may include actuators to eliminate the need for mechanical linkages.

[0039] The joints 44a and 44b include actuators 48a and 48b that are configured to drive the joints 44a, 44b, 44c relative to each other through a series of belts 45a and 45b or other mechanical linkages, such as drive rods, cables, levers, etc. In particular, the actuator 48a is configured to rotate the robotic arm 40 about a longitudinal axis defined by the link 42a.

[0040] refer to Figure 2 The holder 46 defines a second longitudinal axis and is configured to receive an instrument drive unit (IDU) 52 ( Figure 1). The IDU 52 is configured to be coupled to the actuation mechanisms of the surgical instrument 50 and the camera 51 and is configured to move (e.g., rotate) and actuate the instrument 50 and / or the camera 51. The IDU 52 transmits an actuation force from its actuator to the surgical instrument 50 to actuate components of the end effector 49 of the surgical instrument 50. The holder 46 includes a sliding mechanism 46a configured to move the IDU 52 along a second longitudinal axis defined by the holder 46. The holder 46 also includes a joint 46b that rotates the holder 46 relative to the link 42c. During an endoscopic procedure, the instrument 50 can pass through an endoscope access port 55 ( Figure 3 ) is inserted. The holder 46 also includes a port lock 46c ( Figure 2 ).

[0041] The IDU 52 is attached to the holder 46, and then the sterile interface module (SIM) 43 is attached to the distal portion of the IDU 52. The SIM 43 is configured to secure a sterile drape (not shown) to the IDU 52. The instrument 50 is then attached to the SIM 43. The instrument 50 is then inserted through the access port 55 by moving the IDU 52 along the holder 46. The SIM 43 includes a plurality of drive shafts that are configured to transmit the rotation of the respective motors of the IDU 52 to the instrument 50, thereby actuating the instrument 50. In addition, the SIM 43 provides a sterile barrier between the instrument 50 and other components of the robotic arm 40 (including the IDU 52).

[0042] The robot arm 40 also includes a plurality of manual override buttons 53 ( Figure 1 ), the plurality of manual override buttons can be used in manual mode. The user can press one or more of these buttons 53 to move the component associated with the button 53.

[0043] refer to Figure 4, each of the computers 21, 31, 41 of the surgical robot system 10 may include multiple controllers, which may be implemented in hardware and / or software. The computer 21 of the control tower 20 includes a controller 21a and a safety observer 21b. The controller 21a receives data about the current position and / or orientation of the handle controllers 38a and 38b and the status of the foot pedal 36 and other buttons from the computer 31 of the surgeon's console 30. The controller 21a processes these input positions to determine the desired drive commands for each joint of the robotic arm 40 and / or the IDU 52, and transmits these desired drive commands to the computer 41 of the robotic arm 40. The controller 21a also receives the actual joint angles measured by the encoders of the actuators 48a and 48b, and uses this information to determine force feedback commands, which are transmitted back to the computer 31 of the surgeon's console 30 to provide tactile feedback through the handle controllers 38a and 38b. The safety observer 21b performs validity checks on data entering and exiting the controller 21a and, if an error in data transmission is detected, notifies the system fault handler to place the computer 21 and / or surgical robot system 10 into a safe state.

[0044] The computer 41 includes a plurality of controllers, namely, a cart main controller 41a, a mounting arm controller 41b, a robot arm controller 41c, and an instrument drive unit (IDU) controller 41d. The cart main controller 41a receives and processes joint commands from the controller 21a of the computer 21, and transmits them to the mounting arm controller 41b, the robot arm controller 41c, and the IDU controller 41d. The cart main controller 41a also manages instrument exchange and the overall status of the movable cart 60, the robot arm 40, and the IDU 52. The cart main controller 41a also transmits the actual joint angles back to the controller 21a.

[0045] Each of the joints 63a and 63b and the rotatable base 64 of the mounting arm 61 is a passive joint (i.e., there is no actuator therein) that allows manual adjustment by the user. The joints 63a and 63b and the rotatable base 64 include brakes that are disengaged by the user to configure the mounting arm 61. When the brake is engaged, the mounting arm controller 41b monitors the sliding of each of the joints 63a and 63b and the rotatable base 64 of the mounting arm 61, or when the brake is disengaged, the mounting arm controller can be freely moved by the operator without affecting the control of other joints. The robot arm controller 41c controls each joint 44a and 44b of the robot arm 40 and calculates the desired motor torque required for gravity compensation, friction compensation, and closed-loop position control of the robot arm 40. The robot arm controller 41c calculates a movement command based on the calculated torque. The calculated motor command is then transmitted to one or more of the actuators 48a and 48b in the robot arm 40. The actual joint positions are then transmitted by actuators 48a and 48b back to the robot controller 41c.

[0046] The IDU controller 41d receives the desired joint angles (such as wrist and jaw angles) of the surgical instrument 50 and calculates the desired current for the motors in the IDU 52. The IDU controller 41d calculates the actual angles based on the motor positions and transmits the actual angles back to the cart master controller 41a.

[0047] The robotic arm 40 is controlled in response to the posture of the handle controller (e.g., handle controller 38a) controlling the robotic arm 40, which is transformed into the desired posture of the robotic arm 40 by the hand-eye transformation function performed by the controller 21a. The hand-eye function and other functions described herein are implemented in the software that can be executed by the controller 21a or any other suitable controller described herein. The posture of one of the handle controllers 38a can be implemented as a coordinate position and roll-pitch-left-right (RPY) orientation relative to the coordinate reference system fixed to the surgeon's console 30. The desired posture of the instrument 50 is relative to the fixed system on the robotic arm 40. The posture of the handle controller 38a is then scaled by the zoom function performed by the controller 21a. In an embodiment, the coordinate position can be reduced and the orientation can be enlarged by the zoom function. In addition, the controller 21a can also perform a clutch function for disengaging the handle controller 38a from the robotic arm 40. In particular, if certain movement limits or other thresholds are exceeded, the controller 21a stops transmitting movement commands from the handle controller 38a to the robotic arm 40 and essentially acts like a virtual clutch mechanism, eg, limiting mechanical input from affecting mechanical output.

[0048] The desired pose of the manipulator 40 is based on the pose of the handle controller 38a and then passed through the inverse kinematics function executed by the controller 21a. The inverse kinematics function calculates the angles of the joints 44a, 44b, 44c of the manipulator 40 to achieve the scaled and adjusted pose input by the handle controller 38a. The calculated angles are then passed to the manipulator controller 41c, which includes a joint axis controller with a proportional derivative (PD) controller, a friction estimator module, a gravity compensator module, and a double-sided saturation block, which is configured to limit the command torque of the motors of the joints 44a, 44b, 44c.

[0049] refer to Figure 5 , the surgical robotic system 10 is set up around an operating table 100. The system 10 includes movable carts 60a-d, which may be numbered "1" to "4". During set up, each of the carts 60a-d is positioned around the operating table 100. The position and orientation of the carts 60a-d depends on a number of factors, such as the placement of a plurality of access ports 55a-d, which in turn depends on the surgery being performed. Once the port placement is determined, the access ports 55a-d are inserted into the patient, and the carts 60a-d are positioned to insert the instruments 50 and the endoscopic camera 51 into the corresponding ports 55a-d.

[0050] During use, each of the mechanical arms 40a-d engages the latch 46c ( Figure 2 ) is attached to the entry port 55 ( Figure 3 ) is attached to one of the access ports 55a-d inserted into the patient's body. The IDU 52 is attached to the holder 46, and then the SIM 43 is attached to the distal portion of the IDU 52. Thereafter, the instrument 50 is attached to the SIM 43. The instrument 50 is then inserted through the access port 55 by moving the IDU 52 along the holder 46.

[0051] refer to Figure 6 , the IDU 52 is shown in greater detail and is configured to transmit power and actuation force from its motors 152a, 152b, 152c, 152d to the instrument 50 to drive movement of components of the instrument 50, such as articulation, rotation, pitch, yaw, clamping, cutting, etc. The IDU 52 may also be configured to activate or fire electrosurgical energy-based instruments, etc. (e.g., cable drives, pulleys, friction wheels, rack and pinion arrangements, etc.).

[0052] The IDU 52 includes a motor group 150 and a sterile barrier housing 130. The motor group 150 includes motors 152a, 152b, 152c, 152d for controlling various operations of the instrument 50. The instrument 50 is removably connected to the IDU 52. When the motors 152a, 152b, 152c, 152d of the motor group 150 are actuated, the rotation of the drive transmission shafts 154a, 154b, 154c, 154d of the motors 152a, 152b, 152c, 152d is respectively transmitted to the drive assembly of the instrument 50. The instrument 50 is configured to convert the rotational force / movement supplied by the IDU 52 (e.g., via the motors 152a, 152b, 152c, 152d of the motor group 150) into the longitudinal movement or translation of the cable or drive shaft to achieve the end effector 200 ( Figure 7 )’s various functions.

[0053] Each of the motors 152a, 152b, 152c, 152d includes a current sensor 153, a torque sensor 155, and an encoder sensor 157. For simplicity, only the operation of the motor 152a is described below. The sensors 153, 155, 157 monitor the performance of the motor 152a. The current sensor 153 is configured to measure the current consumption of the motor 152a, and the torque sensor 155 is configured to measure the motor torque. The torque sensor 155 can be any force or strain sensor including one or more strain gauges, which are configured to convert mechanical force and / or strain into a sensor signal indicating the torque output by the motor 152a. The encoder 157 can be any device that provides a sensor signal indicating the number of revolutions of the motor 152a, such as a mechanical encoder or an optical encoder. The parameters measured and / or determined by the encoder 157 can include speed, distance, number of revolutions per minute, position, etc. The sensor signals from sensors 153, 155, 157 are transmitted to the IDU controller 41d, which then controls the motors 152a, 152b, 152c, 152d based on the sensor signals. In particular, the motors 152a, 152b, 152c, 152d are controlled by an actuator controller 159, which controls the output torque and angular velocity of the motors 152a, 152b, 152c, 152d. In an embodiment, additional position sensors may also be used, including but not limited to potentiometers, Hall effect sensors, accelerometers, and gyroscopes coupled to the movable component and configured to detect travel distance. In an embodiment, a single controller may perform the functions of the IDU controller 41d and the actuator controller 159.

[0054] refer to Figure 6, the instrument 50 includes an adapter 160 having a housing 162 at a proximal portion thereof and an elongated shaft 164 extending distally from the housing 162. The housing 162 of the instrument 50 is configured to be selectively coupled to the IDU 52 of the robot so that the motors 152a, 152b, 152c, 152d of the IDU 52 of the robotic surgery assembly 100 can operate the end effector 200 of the instrument 50. The housing 162 of the instrument 50 supports a drive assembly that mechanically and / or electrically cooperates with the motors 152a, 152b, 152c, 152d of the IDU 52 of the robotic surgery assembly 100. The drive assembly of the instrument 50 may include any suitable electrical and / or mechanical components to achieve drive force / movement.

[0055] The surgical instrument also includes an end effector 200 coupled to the elongated shaft 164. The end effector 200 may include any number of degrees of freedom that allow the end effector 200 to articulate, pivot, etc. relative to the elongated shaft 164. The end effector 200 may be any suitable surgical end effector configured to treat tissue, such as a dissector, grasper, sealer, stapler, etc.

[0056] like Figure 7 As shown, the end effector 200 may include a pair of opposing jaws 120 and 122 that are movable relative to each other. In an embodiment, the end effector 200 may include a proximal portion 112 and a distal portion 114 having a first pin 113. The end effector 200 may be actuated using a plurality of cables 201 that pass through the proximal portion 112 and the distal portion 114 around their respective pulleys 112a, 112b, 114a, 114b, which are integrally formed as arms of the proximal portion 112 and the distal portion 114. In an embodiment, the end effector 200 (i.e., the distal portion 114 and the jaws 120 and 122) may be articulated about an axis "AA" to control the left-right swing angle of the end effector relative to the longitudinal axis "XX". The distal portion 114 includes a second pin 115, wherein a pair of jaws 120 and 122 are pivotally coupled to the second pin 115. The jaws 120 and 122 are configured to pivot about an axis "BB" defined by the second pin 115 to allow control of the pitch angle of the jaws 120 and 122 and opening and closing the jaws 120 and 122. The yaw, pitch, and jaw angle are controlled by adjusting the tension and / or length and direction (e.g., proximal or distal) of the cable 201. The end effector 200 also includes a cable displacement sensor 116 that is configured to measure the position of the cable 201. Therefore, the end effector 200 can have three degrees of freedom: yaw, pitch, and jaw angle between the jaws 120 and 122.

[0057] End effector 200 may be any grasper suitable for securely grasping suture needle 170 and using needle 170 during a suturing procedure (eg, piercing tissue, pulling suture, etc.). Fig. 8A -C shows the fully closed configuration ( Fig. 8A ), partially opened needle grip configuration ( Figure 8B ), and fully open configuration ( Figure 8C ) of the end effector 200. In the partially open configuration, the end effector 200 is configured to grasp the needle 170, which can have any suitable shape (e.g., straight, curved, etc.) and size (e.g., a diameter from about 0.4 mm to about 1.2 mm). The needle 170 can be formed of any metal (such as stainless steel and its alloys) to provide sufficient strength, ductility, and hardness during the suturing procedure. Since the needle 170 is metal, the needle 170 is conductive. The system 10 uses this property to determine whether the end effector 200 grasps the needle 170, as further described below.

[0058] refer to Fig. 9 , each of the jaws 120 and 122 is formed of a conductive material (e.g., metal) or includes a conductive tissue contact surface. The jaws 120 and 122 are electrically isolated from each other by an insulator 124, which can be formed of any suitable dielectric material. The jaws 120 and 122 are connected to an electrical sensor 140 via a pair of electrical leads 121 and 123, which is configured to provide electrical signals to the jaws 120 and 122 and is configured to measure electrical characteristics. The electrical sensor 140 may include an electrical signal generator configured to output an electrical signal suitable for sensing electrical characteristics (i.e., low current and low voltage). The sensed electrical characteristics may include conductivity, continuity, impedance, resistance, phase, etc., or any other characteristics indicating grasping a metal object. In an embodiment, the electrical sensor 140 may be an electrosurgical generator including built-in sensing capabilities.

[0059] The electrical signal may be continuous or periodic and may have a duty cycle of 100% or less. The electrical sensor 140 may use the signal to detect whether the jaws 120 and 122 are in an open state and are not gripping any object, which corresponds to an open circuit. Thus, when the jaws 120 and 122 are open and not in contact with each other directly or through contact with an object / tissue, the circuit with the electrical sensor 140 is open. Conversely, when the jaws 120 and 122 are closed on tissue and / or needle 170 or any other material, the electrical sensor 140 is configured to measure its impedance. In an embodiment, the electrical sensor 140 may measure the continuity of the circuit formed by the jaws 120 and 122 as well as other electrical characteristics.

[0060] refer to Fig.10, discloses a method for controlling the gripping force of an end effector 200 during suturing. The method can be implemented as software instructions executable by any controller (e.g., controller 21a, 31a, 41a, etc.). In step 300, the system 10 measures the impedance and angle of the end effector 200. The measurements can be performed continuously at a rate of about every 10 milliseconds (ms) or more. As described above, the impedance is measured by the electrical sensor 140, and the angle is measured by the encoder 157, which measures the rotational output of the motor 152a-d to allow the IDU controller 41d to calculate the angle of the jaws 120 and 122 by converting the rotational output into a linear output of the cable or drive shaft that actuates the jaws 120 and 122, which corresponds to the angle.

[0061] At step 302, the controller 21a compares the measured angle to an angle threshold corresponding to a needle 170 grasping configuration. In embodiments, the angle threshold may range, for example, from about 5% to about 10% of the fully open configuration, since an angle above a certain threshold may indicate grasping an object other than the needle 170 (e.g., tissue). The controller 21a also compares the measured impedance to an impedance threshold corresponding to contacting a metallic material. The impedance threshold may be from about 0 ohms to about 5 ohms, which indicates any conductive material. If the measured impedance is above the impedance threshold and the measured angle is equal to or above the angle threshold, then at step 303, the controller 21a (i.e., via the IDU controller 41a) sets the torque of the motors 152a-d to less than 100% of the maximum torque to reduce the gripping force of the end effector 200. In embodiments, the torque may be set to less than 50% of the maximum torque. The measured impedance being above the threshold indicates that the jaws 120 and 122 are not grasping the needle and may be grasping a non-metallic, less conductive material (e.g., tissue, suture, surgical patch, etc.). The reduction in torque applied to jaws 120 and 122 allows for more delicate manipulation of tissue.

[0062] At step 304, the controller 21a determines whether the measured impedance is below an impedance threshold and the measured angle is equal to or above an angle threshold, or alternatively, is within an angle range indicating grasping of the needle 170. If true, then at step 305, the controller 21a has recognized that the jaws 120 and 122 are grasping the needle 170 because the impedance is below a threshold indicating a conductive (i.e., metal) object and the angle indicates grasping of the needle 170. Therefore, the controller 21a sets the torque of the motors 152a-d to 100% of the maximum torque to provide the maximum grasping force of the jaws 120 and 122.

[0063] In step 306, the controller 21a determines whether the measured angle is below the angle threshold, i.e., whether the jaws 120 and 122 are too close to grasp the needle 170, and then in step 307, the controller 21a (i.e., via the IDU controller 41a) sets the torque of the motors 152a-d to less than 100% of the maximum torque to reduce the gripping force of the end effector 200, as in step 305. In an embodiment, the torque may be set to less than 30% of the maximum torque.

[0064] After each of steps 303, 305, and 307, in step 308, the motors 152a-d are operated at the torque setting set by the controller 21a. Therefore, when the needle 170 is grasped, the controller 21a determines this based on the angles and electrical characteristics of the jaws 120 and 122. The controller 21a then increases the gripping force so that the end effector 200 can use the needle 170 to suture the tissue. In particular, when the needle 170 is used to pierce and suture the tissue, the needle 170 is firmly grasped to prevent the needle 170 from falling or slipping. Once the controller 21a releases the needle 170, the controller 21a reduces the gripping force to allow the object to be gently manipulated until the needle 170 is grasped by the jaws 120 and 122.

[0065] This electrical sensing by the electrical sensor 140 allows the system 10 to dynamically change the torque based on the measured angle and impedance to apply a strong grip or a delicate grip depending on the object grasped by the clamps 120 and 122. Therefore, if the tissue or suture is grasped, the torque applied is limited, thereby reducing the grasping force. Limiting the grasping force prevents or reduces the possibility of two major suture failure modes. First, the system and method of the present disclosure reduces the compression yield of the surgical product (e.g., suture, patch, etc.) grasped by the clamps 120 and 122, which may cause stress concentration and potential failure points in the suture. Secondly, the low-force grasping makes it more likely that the grasped suture will slip out of the clamps rather than break due to the suture being exposed to the ultimate tensile stress of the material. Finally, the dynamic adjustment of the grasping force improves the durability of the grasping instrument 50 because the instrument 50 does not need to operate continuously at the maximum grasping force throughout the procedure. The maximum grasping force is limited when the instrument 50 grasps the needle.

[0066] Although the foregoing method is described as using two parameters (i.e., electrical characteristics and angles of the jaws 120 and 122) to determine whether a needle is grasped, it is contemplated that other parameters of the instrument 50 and IDU 52 may also be used to confirm and / or determine the object grasped by the jaws 120 and 122. For example, the torque applied by the motors 152a-d may be measured and used to confirm and / or determine the object being grasped, wherein a high applied torque indicates a hardness of the object (e.g., a needle).

[0067] It will be understood that various modifications may be made to the embodiments disclosed herein. Therefore, the above description should not be interpreted as limiting, but merely as an illustration of various embodiments. Those skilled in the art will envision other modifications within the scope and spirit of the appended claims.

Claims

1. A surgical robot system, comprising: a robotic arm comprising an instrument having a pair of opposing jaws configured for gripping, and an instrument drive unit configured to couple to the instrument and actuate the instrument; a surgeon console including a handle controller configured to control the robotic arm and the instrument; as well as A controller, the controller being configured to: receiving an electrical characteristic of the opposing jaws; receiving a measurement of the angle of the opposing jaws; determining whether the opposing jaws grasp a metal object based on electrical characteristics and angles of the opposing jaws to form a determination; and A gripping force of the opposing jaws is adjusted based on the determination. 2 . The surgical robot system according to claim 1 , further comprising an electrical sensor configured to measure the electrical characteristic.

3. The surgical robot system according to claim 1, wherein: The electrical characteristic is impedance.

4. The surgical robot system according to claim 3, wherein: The controller is further configured to compare the impedance to a threshold impedance corresponding to the metal object to determine whether the opposing jaws grasp the metal object.

5. The surgical robot system according to claim 1, wherein: The metal object is a suture needle.

6. The surgical robot system according to claim 5, wherein: The controller is further configured to measure the angle of the opposing jaws based on at least one of motor position, torque, or current.

7. The surgical robot system according to claim 6, wherein: The controller is further configured to compare the measured angle to a threshold angle configured to grasp the needle to determine whether the opposing jaws grasp the metal object.

8. The surgical robot system according to claim 5, wherein: The controller is further configured to: determining whether the opposing jaws grasp the suture needle based on electrical characteristics and angles of the opposing jaws; and A gripping force of the opposing jaws is adjusted based on the determination.

9. The surgical robot system according to claim 8, wherein: During the adjustment of the gripping force, the controller is further configured to increase the gripping force in response to determining that the suturing needle is gripped.

10. The surgical robot system according to claim 8, wherein: During the adjustment of the gripping force, the controller is further configured to reduce the gripping force in response to determining that the suturing needle is not gripped.

11. A surgical robot system, comprising: A mechanical arm, the mechanical arm comprising: an instrument having a pair of opposed jaws configured for grasping; and An instrument drive unit, the instrument drive unit being configured to be coupled to the instrument, the instrument drive unit comprising: at least one motor configured to actuate the opposing jaws between an open configuration and a closed configuration; and a sensor configured to determine an angle between the opposing jaws; a surgeon console including a handle controller configured to control the robotic arm and the instrument; an electrical sensor in electrical communication with the pair of opposing jaws and configured to measure an electrical characteristic of the opposing jaws; and A controller, the controller being configured to: determining whether the opposing jaws grasp a suture needle based on the measured electrical characteristics and the measured angle of the opposing jaws; and A gripping force of the opposing jaws is adjusted based on the determination.

12. The surgical robot system according to claim 11, wherein: The electrical characteristic is impedance.

13. The surgical robot system according to claim 12, wherein: In determining whether the opposing jaws grasp the suturing needle, the controller is further configured to compare the impedance to a threshold impedance corresponding to the suturing needle.

14. The surgical robot system according to claim 11, wherein: The sensor is a motor encoder configured to measure a rotational output of the at least one motor, and the instrument drive unit includes a drive controller configured to calculate the angle based on the rotational output.

15. The surgical robot system according to claim 11, wherein: The controller is further configured to increase the gripping force in response to determining that the suturing needle is gripped.

16. The surgical robot system according to claim 11, wherein: The controller is further configured to reduce the gripping force in response to determining that the suturing needle is not gripped.

17. A method for controlling a motorized machine, the method comprising: measuring electrical characteristics of opposing jaws of the motorized instrument actuated by an instrument drive unit including at least one motor; measuring the angle of the opposing jaws; at a controller, determining whether the opposing jaws grasp a suture needle based on the measured electrical characteristics and the measured angle of the opposing jaws; as well as The torque of the at least one motor actuating the opposing jaws is adjusted based on the determination.

18. The method of claim 17, further comprising increasing a gripping force of the opposing jaws in response to determining that the suture needle is grasped.

19. The method of claim 17, further comprising reducing a gripping force of the opposing jaws in response to determining that the suture needle is not grasped.

20. The method according to claim 17, wherein: The electrical characteristic is impedance, and the method further includes comparing the impedance to a threshold impedance corresponding to the suture needle.

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