Nussbaum-Based Fixed-Time Adaptive Fault-Tolerant Control and Its Application to Robot Manipulator

This paper is concerned with the fixed-time tracking control for nonlinear systems (NOSs) under time-varying failures and input saturation. A new fixed-time fuzzy adaptive fault-tolerant control scheme utilizing Nussbaum functions is presented for NOSs. The fixed-time command filter technique is employed to address the “explosion of complexity” issue, and the new fixed-time compensation signals are constructed to eliminate filtering errors. The Nussbaum function is used to compensate for the effects of time-varying failures and input saturation on NOSs. The constructed controller, based on the improved practical fixed-time stability criterion, ensures that the tracking error of the NOS converges to the neighborhood of the origin in a fixed time. Finally, the effectiveness and advantages of the presented strategy are verified by a consumer robot manipulator system.