Estimating joint friction and tracking error of a robotics end effector
AssigneeVerb Surgical Inc.
InventorAlireza Hariri
Life of this patent
Estimating the term…
Abstract
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.
Claims20
A computerized method for controlling movement of an end effector having a robotic wrist, the method comprising the following operations performed by a computer system:
- producing sensor measurements of force or torque in a transmission that mechanically couples the robotic wrist to an actuator, wherein the sensor measurements are cable force measurements;
- estimating joint friction in a joint of the robotic wrist, based on the cable force measurements, by relating the cable force measurements to a joint friction variable;
- and
- performing control tasks to control movement of the end effector, by using the estimated joint friction.
An article of manufacture comprising a computer-readable storage medium having stored therein instructions that configure a processor to:
- produce sensor measurements of force or torque in a transmission, wherein the transmission mechanically couples a robotic wrist of an end effector to an actuator so the actuator can drive a joint of the robotic wrist and the sensor measurements are cable force measurements;
- estimate joint friction in the joint of the robotic wrist based on the cable force measurements, by relating the cable force measurements to a joint friction variable;
- and
- perform control tasks to control movement of the end effector, by using the estimated joint friction.
The article of manufacture of 19 wherein the computer-readable storage medium has stored therein further instructions that configure the processor to use the estimated joint friction by computing a tracking error of the end effector based on the joint friction variable.
Dependencies are inferred from the claim text.