Control of a surgical instrument having backlash, friction, and compliance under external load in a surgical robotic system
AssigneeVerb Surgical Inc.
InventorsH. Tutkun Sen, Alireza Hariri
Life of this patent
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Abstract
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.
Claims19
A method for control of a surgical instrument in a surgical robotic system, the method comprising:
- actuating a first linkage engaged with a first motor and a second linkage engaged with a second motor, the first and second linkages mechanically coupled to an end effector of the surgical instrument, the first and second motors operating under torque control in opposition to each other, the torque control using control inputs for torque;
- compensating for backlash from the first and second motors through the first and second linkages to the end effector;
- transitioning to position control from the torque control of the first and second motors when a threshold torque is reached;
- and
- driving the end effector in position control of the first and second motors, the first and second motors operating in coordination with each other.
A surgical robotic system for control of a surgical instrument, the surgical robotic system comprising:
- a surgical end effector actuated by a first actuator and a second actuator through a transmission;
- and
- a controller configured to drive the first actuator and/or second actuator so as to cause the first actuator and the second actuator to operate in opposition to cause a static pretension during homing of the first actuator and second actuator.
A method for control of a surgical tool in a surgical robotic system, the method comprising:
- overcoming variable backlash due to compliance of engaged couplings between actuators and the surgical tool by the actuators operating in opposition to each other relative to actuation of the surgical tool;
- and
- controlling the actuators with position commands so that a same relative position of drive shafts of the actuators is maintained as the surgical tool moves under control of the actuators.
Dependencies are inferred from the claim text.