Fixed-Time Fuzzy Adaptive Fault-Tolerant Control for Strict-Feedback Nonlinear Systems With Input Delay
针对存在执行器故障和输入时滞的严格反馈非线性系统，提出一种固定时间模糊自适应容错控制算法，利用模糊逻辑系统和Pade近似分别处理未知非线性和输入时滞，并通过命令滤波技术消除计算复杂度爆炸问题，仿真验证了该方法在收敛速度和稳态误差方面的优越性。
This article aims to investigate the problem of fixed-time fuzzy adaptive fault-tolerant tracking control for strict-feedback nonlinear systems (SFNSs) suffering from actuator fault and input delay. In practical engineering applications, actuator fault and input delay are two common problems, which are easy to affect system performance and cause adverse consequences. To rapidly deal with these two problems, a fixed-time fuzzy adaptive fault-tolerant control (FTC) algorithm is proposed. Specifically, fuzzy logic systems (FLSs) and Pade approximation method are applied to address the unknown nonlinearity and the input delay issues, respectively. Besides, command filter technique is applied to replace the traditional backstepping method to eliminate “complexity explosion” issue in calculation process. Under the role of fixed-time controller, the effects of input delay and actuator fault are rapidly suppressed, and the controlled system can obtain the better control performance on convergence speed and steady-state error. The comparative simulation examples demonstrate that the controller utilizing fixed-time stability has better control and fault tolerance performance, thus verifying the superiority of the proposed method.