A Faster Fixed-Time Fault Tolerant Sliding Mode Control for Robot Manipulators With Mismatched Disturbances

Mismatched disturbances and actuator failures are primary challenges in the field of robotic manipulators. This research proposes a faster disturbance observer-based fixed-time sliding manifold with accelerated convergence rate developing a comprehensive strategy capable of addressing both of these limitations, which have garnered little attention from researchers so far. First, a disturbance observer is introduced to estimate fault information, matched and mismatched disturbances. With the estimated information, a novel faster fixed-time nonsingular terminal sliding manifold is designed, and a control law is formulated to compensate for the faults and disturbances. Additionally, a fixed-time adaptive algorithm is developed to approximate the upper bound of observer errors. The Lyapunov function is utilized to ensure fixed-time stability and faster convergence of the proposed approach. Finally, simulations and comparative analyses are conducted to confirm the robustness and superiority of the proposed scheme despite the presence of mismatched disturbances and actuator faults. This main contributions of this research lies in a novel disturbance observer-based terminal sliding manifold with faster convergence is proposed, developing a comprehensive strategy capable of handling both mismatched disturbances and actuator failures.