US 7,899,578 B2 · Medical robotic system with sliding mode control

Abstract

A medical robotic system has a joint coupled to medical device or a slave manipulator or robotic arm adapted to hold and/or move the medical device for performing a medical procedure, and a control system for controlling movement of the joint according to user manipulation of a master manipulator. The control system includes at least one joint controller having a sliding mode control for reducing stick-slip behavior on its controlled joint during fine motions of the joint. The sliding mode control computes a distance to a sliding surface, computes a reaching law gain, and processes the distance and reaching law gain to generate a sliding mode control action that is in absolute value less that a maximum desired feedback control action. The sliding mode control action is then further processed to generate a feedback torque command for the joint motor.

Claims14

Dependent claims

A method using sliding mode control for controlling movement of a joint in a medical robotic system in response to user manipulation of a master input device, comprising:

computing a distance from a sliding mode surface using the following equation:
σ=λ·(QC−QL)+(VC−VL), wherein σ represents the distance, λ is a parameter value, (QC−QL) is a position error and (VC−VL) is a velocity error associated with commanded movement of the joint by the master input device;
computing a sliding mode control action using a non-linear function of the distance to the sliding mode surface;
and
causing the joint to be moved at least partially in response to the sliding mode control action.

2 more elements

Dependencies are inferred from the claim text.

Medical robotic system with sliding mode control

Life of this patent

Medical robotic system with sliding mode control

Life of this patent

Abstract

Claims14