Fault-tolerant control of a 2-DOF robot manipulator using multi-sensor switching strategy

In this paper, a fault-tolerant multi-sensor switching strategy is used for sensor-fault tolerance of robot manipulator with redundant sensors in each joint to provide the angular position of the joint. This strategy employs a linear-parameter-varying (LPV) model to describe the nonlinear dynamics of the robot manipulator. Then, based on the obtained LPV model, a zonotopic set-based robust fault detection (FD) mechanism is further designed to monitor the system behaviors. At each time instant, the FD mechanism checks whether there are some sensors that have become faulty to make FD decisions. A switching controller is designed to choose the best estimation among the healthy sensors to generate closed-loop control laws. Once a sensor has become faulty and is detected by the FD mechanism, the fault-tolerant strategy discards the faulty sensor and uses the healthy one to implement closed-loop control. At the end, some simulation results are presented to illustrate the effectiveness of the proposed fault-tolerant control (FTC) strategy.