A Sliding-Mode Fault Tolerant Control for Robotic Manipulators Based on Actuator Switching

In this paper, a sliding-mode fault tolerant control (FTC) based on actuator switching is proposed for a class of n-link robotic manipulators with actuator failures and disturbances, for which, each joint is driven by an actuator with several healthy actuators as backups. First, a sliding-mode controller is designed, and then based on the value of the sliding surfaces, a set of monitoring functions (MFs) is constructed to tackle those serious actuator failures. It is shown that with the proposed scheme, all signals of the closed-loop system are bounded. A two-link robotic manipulator example is used to verify the effectiveness of the control scheme.