Fault detection response in a robot arm
AssigneeCmr Surgical Limited
InventorPaul Roberts
Life of this patent
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Abstract
A robot arm comprising: a first link connected to a second link by a joint, the joint permitting the second link to move relative to the first link; a motor for driving the joint; and a controller for controlling the motor. The controller is configured to electrically brake the motor in response to detection of a fault in the robot arm by applying a braking current to the motor so as to maintain the position of the joint against gravity. The controller only performs this electrical braking if the joint is in a configuration in which the robot arm will droop under gravity if the joint is not actively driven.
Claims19
A robot arm comprising:
- a first link connected to a second link by a joint, the joint permitting the second link to move relative to the first link;
- a motor configured to drive the joint;
- and
- a controller configured to control the motor, the controller configured to electrically brake the motor in response to detection of a fault in the robot arm by applying a braking current to the motor so as to maintain the position of the joint against gravity;
- wherein the fault is a loss of power, and the controller is configured to electrically brake the motor in response to detection of the loss of power by connecting the braking current to the motor from a back-up power supply external to the robot arm.
Dependencies are inferred from the claim text.