Observer-Based Adaptive Fuzzy Quantized Fault-Tolerant Control of Nonstrict-Feedback Nonlinear Systems With Sensor Fault
Tiantian Wu, Zhaoxu Yu, Shugang Li
Abstract
This article focuses on the problem of adaptive quantized fault-tolerant tracking control for a class of uncertain nonstrict-feedback nonlinear systems in the presence of input and output quantization and sensor fault. The main technical challenges come from how to deal with the input and output quantization errors and the partial loss of sensors' effectiveness. First, a new observer, including the quantized input and output signals and the estimation of fault parameter, is designed to reconstruct the unavailable states, and some special techniques are developed to deal with the sector-bounded quantization errors. Furthermore, based on the cubic absolute-value Lyapunov function, the adaptive fault compensation strategy is presented to make up for the influence from sensor fault upon the control performance. Then, with the aid of the fuzzy logic system approximation method and the backstepping technique, a novel output feedback adaptive fuzzy fault-tolerant control scheme is proposed for this class of systems, such that all the signals in the closed-loop system are semiglobally uniformly ultimately bounded, while the tracking error remains in a small vicinity of the origin. Finally, the effectiveness and the applicability of the proposed control scheme are validated by conducting two simulation examples.