Command Filtered Adaptive Fault-Tolerant Fixed-Time Control of Nonlinear Systems Based on Tuning Functions

The problem of adaptive fault-tolerant fixed-time control is studied for a class of strict-feedback nonlinear systems with multiple faults and multiple disturbances. We incorporate the tuning functions and the command filter technique into the controller design. Note that the former reduces the order of the controller, and the latter simplifies the derivation and calculation process and avoids the high calculation cost and differential explosion. In addition, since our proposed strategy is based on fixed-time control, it can ensure that the closed-loop system keeps the practically fixed-time stable, and the tracking error converges to a small neighborhood near the origin within fixed-time. As for the unknown items in the systems, fuzzy logic systems are used to approximate them. The simulation results show that the proposed control strategy is effective even if there exist actuator faults and multiple disturbances.