Adaptive robust self-tuning PID fault-tolerant control for robot manipulators

In this research, by combining the filtered tracking error and the proportional-derivative-integral (PID) techniques, a novel of adaptive robust PID strategy has been explored for the robot manipulators (RM) system in presence of faults. In the proposed control system, the PID gains are adaptively self-updated to deal with time-varying uncertainties (the unknown RM dynamics, instantaneous faults, and disturbances) that are fully estimated by two adaptive estimators. In addition, in order to enhance the control robustness, a smooth robust compensator is also designed for decreasing the inevitable approximating/updating errors caused by uncertain faults, as well as limitation of the chattering phenomenon. Moreover, all designed updating/estimating algorithms are carried out online in considering of the Lyapunov stability criteria. The compared numerical simulation results are considered to verify effectiveness of the proposed RM fault control system.