Fault Tolerant Control Using Fractional-order Terminal Sliding Mode Control for Robotic Manipulators

In this paper, Fractional-order Non-singular Fast Terminal Sliding Mode Control based Fault Tolerant Control (FONFTSM-FTC) is investigated for robotic manipulators in the presence of uncertainties, unknown external load disturbances and actuator faults. Firstly, Fractional-order Non-singular Fast Terminal Sliding Mode Control (FONFTSM) is proposed, in which Fractional-order is used to obtain good tracking performance, and Non-singular Fast Terminal Sliding Mode Control is utilized to achieve fast finite-time convergence, non-singularity and chatter-free control inputs. Secondly, FONFTSM with Adaptive scheme is used as a robust Fault Tolerant Control (FTC) to estimate the uncertainties as well as actuator faults without prior knowledge of the upper bounds. Asymptotical stability of the closed-loop system is obtained by Lyapunov analysis. Finally, corresponding simulation results with compared recent methods of adaptive FONFTSM (AFONTSM) and Non-singular Fast Terminal Sliding Mode Control based Active FTC (NFTSMC-FTC) are made to validate and demonstrate the effectiveness of the proposed method.