Open-loop torque control on joint position-controlled robots
AssigneeHonda Motor Co., Ltd.
InventorTaizo Yoshikawa
Life of this patent
Estimating the term…
Abstract
A joint of a robot is controlled by a torque command. The joint has a position controller with a position feedback loop. The torque command is received for the joint, and a velocity feedforward command is determined for realizing the torque command using the position controller. The velocity feedforward command is sent to the position controller and the position feedback loop is canceled. The position feedback loop is canceled by sending a position command to the position controller, where the position command is an actual measured position of the joint. The position feedback loop is also canceled by setting the gain of the position feedback loop to zero.
Claims20
A method for controlling a joint of a robot, the joint having a position controller with a position feedback loop, the position controller having a velocity feedforward input configured to receive a desired velocity of the joint and a position input configured to receive a desired position of the joint, and the position controller configured to control motion of the joint to achieve the desired velocity and desired position, the method comprising:
- receiving, by a torque-to-velocity transformer, a torque command for the joint representing a desired torque of the joint;
- determining, a velocity feedforward command that when inputted to a velocity feedforward input of the position controller causes the position controller to control a physical joint of the robot to achieve the desired torque;
- sending the velocity feedforward command to the position controller;
- and
- sending a command to the position controller that cancels an effect of the position feedback loop.
A torque-to-velocity transformer for controlling a joint of a robot, the joint having a position controller with a position feedback loop, the position controller having a velocity feedforward input configured to receive a desired velocity of the joint and a position input configured to receive a desired position of the joint, and the position controller configured to control motion of the joint to achieve the desired velocity and desired position, the torque-to-velocity transformer comprising:
- a receiving module for receiving a torque command for the joint representing a desired torque of the joint;
- a determining module for-determining a velocity feedforward command that when inputted to a velocity feedforward input of the position controller causes the position controller to control a physical joint of the robot to achieve the desired torque;
- a sending module for sending the velocity feedforward command to the position controller;
- and
- a canceling module for sending a command to the position controller that canceling cancels an effect of the position feedback loop.
Dependencies are inferred from the claim text.