Fault detection and robust fault recovery control for robot manipulators with actuator failures

This paper presents a fault detection strategy and a robust fault recovery control scheme for robot manipulators to overcome the actuator failures. The joint (or actuator) failure considered is the free-swinging joint failure that causes the loss of torque on a joint. The proposed fault-tolerant control framework includes a normal control with normal (non-failed) operation, a fault detection and a fault recovery control to achieve task completion. After the detection and identification of joint failures, the robot manipulator becomes an underactuated manipulator with failed actuators. Then the underactuated manipulator can be controlled by the presented robust controller. To show the feasibility of the proposed fault-tolerant control scheme, simulation results for a three-link planar robot arm with a failed joint are presented