Predefined-Time Prescribed Performance Fault-Tolerant Control for a Class of Uncertain Nonlinear Systems Under Full State Constraints

Abstract

This study introduces a fault-tolerant control approach aimed at enhancing the control performance of a certain type of nonlinear systems that are prone to actuator faults and external disturbances. This combined fault disturbance term, along with the systems' external disturbance terms, are estimated by specially designed predefined-time observers. To achieve fault tolerance, a predefined-time fault-tolerant controller is designed by integrating the asymmetric barrier Lyapunov function (ABLF) with the improved prescribed performance function (IPPF). The ABLF is utilized to address the issue of full state constraints, while the IPPF ensures that the system states meet specific performance requirements. Additionally, novel command filters are introduced to alleviate the “explosion of complexity” issue, thereby reducing the system's computational burden. The theoretical analysis demonstrates that the proposed method drives the closed-loop system to converge to a neighborhood near the equilibrium point within a predefined time, while also guaranteeing that all system states remain within specified constraint boundaries. Finally, the validity and feasibility of the proposed method are validated through simulations and dSPACE experiments.