Verb Surgical Inc.

Alireza Hariri

Ali Asadian

Renbin Zhou

Andrew Dahdouh

Haoran Yu

Sina Nia Kosari

Xiaobin Zhang

H Tutkun Sen

Edgar Ignacio Ergueta Tejerina

Hasan Tutkun Sen

Apoorv Shrivastava

Spencer Maughan

The disclosed embodiments relate to systems and methods for a surgical tool or a surgical robotic system. One example system for detecting a hardstop for a surgical tool includes a wrist connected to and driven by a plurality of cables of a tool driver, a plurality of sensors configured to detect forces associated with the plurality of cables one or more processors configured to perform a comparison of the forces associated with the plurality of cables, selected a highest tension cable from the plurality of cables based on the comparison of the forces associated with the plurality of cables, set a force assigned to the highest tension cable to a predetermined value, calculate a variable torque threshold for the wrist based on a sum of the predetermined value for the highest tension cable and detected forces for remaining cables in the plurality of cables, receive a joint torque value for the wrist, perform a comparison of the received joint torque value for the wrist to a variable wrist torque threshold and identify a hardstop based on the comparison of the received joint torque value for the wrist to the variable wrist torque threshold.

Hardstop detection and handling for surgical tool

For a scalable filtering infrastructure, a library of filters each usable at different control rates is provided by defining filters in a continuous time mode despite eventual use for digital filtering. For implementation, a filter is selected and discretized for the desired control rate. The discretized filter is then deployed as a discrete time realization for convolution. In a distributed system with multiple control rates, the library may be used to more rapidly and conveniently generate the desired filters.

Scalable filtering infrastructure for variable control rates in a distributed system such as a surgical robotic system

The disclosed embodiments relate to systems and methods for a surgical tool or a surgical robotic system. An end effector of the surgical tool is coupled to a tool driver. An actuator is driven by a motor of the tool driver and configured to drive a degree of freedom of the end effector. One or more processors are configured to receive a position command describing a desired position for the end effector, translate the desired position to a command for a joint associated with the end effector, calculate a compensation term to compensate for a source of hysteresis for backlash and/or compliance, and send a motor command for the motor coupled with the actuator based on the compensation term and the command for the end effector.

Joint calibration for surgical tool

A system and computerized method for detection of engagement of a surgical tool to a tool drive of a robotic arm of a surgical robotic system. The method may include activating an actuator of the tool drive to rotate a drive disk to be mechanically engaged with a tool disk in the surgical tool. One or more motor operating parameters of the actuator that is causing the rotation of the drive disk are monitored while activating the actuator. The method detects when the drive disk becomes mechanically engaged with the tool disk, based on the one or more monitored motor operating parameters. Other embodiments are also described and claimed.

Method and system for engagement of a surgical tool with actuators of a tool drive in a surgical robotic system

A computerized method for estimating joint friction in a joint of a robotic wrist of an end effector. Sensor measurements of force or torque in a transmission that mechanically couples a robotic wrist to an actuator, are produced. Joint friction in a joint of the robotic wrist that is driven by the actuator is computed by applying the sensor measurements of force or torque to a closed form mathematical expression that relates transmission force or torque variables to a joint friction variable. A tracking error of the end effector is also computed, using a closed form mathematical expression that relates the joint friction variable to the tracking error. Other aspects are also described and claimed.

Estimating joint friction and tracking error of a robotics end effector

The disclosed embodiments relate to systems and methods for a surgical tool or a surgical robotic system. A tool driver is coupled to a distal end of a robotic arm and includes a roll drive disk driven by a rotary motor. One or more processors are configured to detect an attachment of a surgical tool to the tool driver. The surgical tool includes a roll tool disk to be engaged with the roll drive disk of the tool driver, actuate of the roll drive disk through the rotary motor, determine that a measured torque of the rotary motor exceeds a preset torque threshold for a preset period of time since the actuation, and report a successful engagement between the roll drive disk and the roll tool disk.

Engagement, homing, and control of robotics surgical instrument

The disclosure relate to systems and methods for a surgical tool or a surgical robotic system. An example computer-implemented method for evaluating calibrations of a surgical tool includes fixating a joint of the surgical tool at a first angle, the joint being driven by an actuator, measuring an actuator position corresponding to the first angle, accessing a calibrated offset corresponding to the first angle, determining an expected joint angle based on the measured actuator position and the calibrated offset, and reporting a first difference between the expected joint angle and the first angle.

Evaluation of calibration for surgical tool

A surgical robotic tool used with a surgical robotic system can include cables that effect movement in the surgical robotic tool. A brake in any of these cables can be detected by checking a plurality of conditions. A process can compare a) a tension error against a first threshold, b) a rate of change of the sensed tension of the cable against a second threshold, and c) a rate of change of a cable extension error against a third threshold. If all thresholds are exceeded, the process can disable the respective actuator.

Detecting cable breakage on cable driven tools

The disclosed embodiments relate to systems and methods for a surgical tool or a surgical robotic system. One example system for detecting disengagement of a surgical tool, includes an end effector connected to and driven by cables of a tool driver, sensors configured to detect forces associated with the cables, and one or more processors. The one or more processors identify cable tensions derived from forces detected by the sensors, compare the tension to a threshold tension value, calculate a velocity norm value based on a vector including the velocity value for each of the cables, compare the velocity norm value to a statistic velocity threshold, and identify a disengagement of at least one of the plurality of cables based on the first comparison and the second comparison.

Detection of disengagement in cable driven tool

Disclosed are systems and methods for limiting the grip force generated by closing robotic wrist jaws while operating in position mode in which the jaws are commanded to a desired jaw angle prior to being commanded to generate a grip force. In the positional mode, the desired jaw angle is above a threshold that corresponds to an angle at which both jaws are just simultaneously in contact with an object between the jaws or, if there is no object to grasp, when the jaws begin to touch each other. A feedback loop may analyze the desired jaw angle and the measured grip force to determine if the jaws are closing in the position mode and if the measured grip force exceeds a maximum grip force threshold. If so, the feedback loop may calculate a grip force error to limit the measured grip force to the maximum grip force threshold.

Systems and methods for limiting grip force of closing jaws in position control mode

For control of a surgical instrument in a surgical robotic system, multiple actuators establish a static pretension by actuating in opposition to each other in torque control. The static pretension reduces or removes the compliance and elasticity, reducing the backlash width. To drive the tool, the actuators are then moved in cooperation with each other in position mode control so that the movement maintains the static pretension while providing precise control.

Control of a surgical instrument having backlash, friction, and compliance under external load in a surgical robotic system

The disclosed embodiments relate to systems and methods for a surgical tool or a surgical robotic system. An actuator or a motor of a tool driver is configured to operate a joint of a tool. One or more processors are configured to receive an initial joint command for the joint of the tool, determine a joint torque based on motor torque of the motor or actuator as well as motor to joint torque mapping, calculate a tip force based on an effective length associated with the joint and based on the joint torque, compare the tip force to a predetermined threshold, calculate an admittance control compensation term in response to the tip force exceeding the predetermined threshold, and generate a command for the motor or actuator based on the admittance control compensation term and the initial joint command.

Admittance compensation for surgical tool

Disclosed are systems and methods for achieving a smooth transition in the grip force when the wrist jaws transition between the position and force mode. In the position mode, the desired jaw angle is above a threshold corresponding to an angle at which both jaws are just simultaneously in contact with an object held between the jaws or, if there is no object, when the jaws begin to touch each other. A feedback loop may determine that the jaws are transitioning between the modes based on changes of the desired jaw angle. The feedback loop may analyze the commanded grip force and the measured grip force to determine whether to adjust the commanded grip force during the transition. If so, the feedback loop may adjust the commanded grip force to reduce changes in the measured grip force that is otherwise based on the desired jaw angle.

Growing community of inventors

Berkeley, CA, United States of America

Alireza Hariri