Surgical robotic tool multi-motor actuator and controller

Patent metadata

Field	Value
Publication number	US-11071441-B2
Application number	US-201815959106-A
Country	US
Kind code	B2
Filing date	Apr 20, 2018
Priority date	Apr 20, 2018
Publication date	Jul 27, 2021
Grant date	Jul 27, 2021

Abstract

A first input coupling and a second input coupling are coupled to rotatably drive an output coupling at the same time. In one embodiment, the output coupling rotates a robotic surgery endoscope about a longitudinal axis of the output coupling. A first motor drives the first input coupling while being assisted by a second motor that is driving the second input coupling. A first compensator produces a first motor input based on a position error and in accordance with a position control law, and a second compensator produces a second motor input based on the position error and in accordance with an impedance control law. In another embodiment, the second compensator receives a measured torque of the first motor. Other embodiments are also described and claimed.

First claim

What is claimed is:

1. A multi-motor actuator and controller for a surgical robotic tool, comprising:
an output coupling configured to be coupled to a surgical tool;
a first input coupling and a second input coupling each coupled to drive the output coupling through a transmission;
a first motor having a drive coupling coupled to drive the first input coupling in accordance with a first motor input command;
a second motor having a drive coupling coupled to drive the second input coupling in accordance with a second motor input command; and
a controller to determine a position error based on a difference between i) a position input command and ii) a position feedback, wherein the position feedback is from the first input coupling and wherein the controller is to
a) produce the first motor input command based on the position error and in accordance with a position control law, and
b) produce the second motor input command based on the position error and in accordance with an impedance control law using a second velocity variable that is obtained from i) the position input command or ii) as feedback from one of the first input coupling, the second input coupling, or the output coupling.

2. The multi-motor actuator and controller of claim 1 wherein the controller comprises:
a first compensator for the position control law that uses a first velocity variable that is obtained i) from the position input command or ii) as feedback from the first input coupling, the second input coupling, or the output coupling; and
a second compensator for the impedance control law.

3. The multi-motor actuator and controller of claim 2 wherein the first velocity variable is obtained as feedback from the first input coupling, and the second velocity variable is obtained as feedback from the second input coupling.

4. The multi-motor actuator and controller of claim 2 wherein the first compensator for the position control law comprises a proportional-integral-derivative, PID, compensator, and the second compensator that implements the impedance control law comprises a proportional-derivative, PD, compensator.

5. The multi-motor actuator and controller of claim 4 wherein the first velocity variable is obtained as feedback from the first input coupling, and the second velocity variable is obtained as feedback from the second input coupling.

6. The multi-motor actuator and controller of claim 5 wherein the controller comprises a friction model that is configured to produce a torque boost input that increases the second motor input, and
wherein the torque boost input is produced as a function of a velocity variable that is obtained from one of: the position input command, feedback from the first input coupling, feedback from the second input coupling, or feedback from the output coupling.

7. The multi-motor actuator and controller of claim 1 wherein each of the first motor and the second motor is undersized in that its respective torque rating is insufficient to drive the output coupling by itself through the transmission.

8. The multi-motor actuator and controller of claim 7 wherein the transmission comprises a first part that is housed in a tool drive housing, and a second part that is housed in an instrument housing separate from the tool drive housing and that is detachable therefrom,
wherein the first input coupling comprises a first tool drive coupling in the tool drive housing that is engaged with a first mating drive coupling in the instrument housing, and the second input coupling comprises a second tool drive coupling in the tool drive housing that is engaged with a second mating drive coupling in the instrument housing.

9. The multi-motor actuator and controller of claim 1 further comprising:
an endoscope camera coupled to the output coupling so as to rotate as one with the output coupling; and
an endoscope camera cable having one end coupled to the endoscope camera and extending through a hollow in the output coupling, wherein the cable twists and resists rotation of the output coupling.

10. A multi-motor actuator and controller for a robotic surgery tool, comprising:
an output coupling configured to be coupled to a surgery tool;
a first input coupling and a second input coupling each coupled to rotatably drive the output coupling at the same time through a transmission;
a first motor subsystem having a first motor whose drive coupling is coupled to rotate the first input coupling, and a first motor driver circuit configured to manipulate power drawn by the first motor in accordance with a first motor subsystem input;
a second motor subsystem having a second motor whose drive coupling is coupled to rotate the second input coupling, and a second motor driver circuit configured to manipulate power drawn by the second motor in accordance with a second motor subsystem input; and
a controller configured to calculate a position error between i) a position input and ii) a position feedback, wherein the position feedback is from the first input coupling, the second input coupling or the output coupling, and wherein the controller is further configured to
a) produce the first motor subsystem input in accordance with a position control law and based on providing the position error as input to a first compensator, and
b) measure torque of the first motor subsystem and low pass filter the measured torque as input to a second compensator, to produce the second motor subsystem input.

11. The multi-motor actuator and controller of claim 10 wherein the first compensator comprises a cascaded PID compensator.

12. The multi-motor actuator and controller of claim 11 wherein the second compensator comprises a proportional-integral, PI, compensator.

13. The multi-motor actuator and controller of claim 10 wherein the controller comprises a friction model that is configured to produce a torque boost input that increases the first motor subsystem input or the second motor subsystem input, and
wherein the torque boost input is produced as a function of a velocity variable that is obtained from one of: the position input, feedback from the first input coupling, feedback from the second input coupling, or feedback from the output coupling.

14. The multi-motor actuator and controller of claim 10 wherein each of the first motor and the second motor is undersized in that its respective torque rating is insufficient to drive the output coupling by itself, through the transmission.

15. The multi-motor actuator and controller of claim 10 wherein the position feedback is from the first input coupling.

16. The multi-motor actuator and controller of claim 10 further comprising:
an endoscope camera coupled to the output coupling so as to rotate as one with the output coupling; and
an endoscope camera cable having one end coupled to the endoscope camera and extending through a hollow in the output coupling, wherein the cable is to twist when resisting rotation of the output coupling,
and wherein the transmission comprises a first part that is housed in a tool drive housing, and a second part that is housed in an instrument housing,
wherein the first input coupling comprises a first tool drive coupling in the tool drive housing that is engaged with a first mating drive coupling in the instrument housing to transmit torque of the first motor to the output coupling, and the second input coupling comprises a second tool drive disk in the tool drive housing that is engaged with a second mating drive coupling in the instrument housing to transmit torque of the second motor to the output coupling.

17.

Assignees

• Verb Surgical Inc

Inventors

• Yu Haoran
• Zhou Renbin
• Nia Kosari Sina
• Bajo Andrea

Classifications

• A61B1/00006 Primary

  of control signals · CPC title

• A61B1/3132

  for laparoscopy · CPC title

• A61B17/29

  Forceps for use in minimally invasive surgery · CPC title

• A61B34/30

  Surgical robots · CPC title

• A61B2034/301

  for introducing or steering flexible instruments inserted into the body, e.g. catheters or endoscopes · CPC title