Fault-Tolerant Control of a Nonlinear System Based on Generalized Fuzzy Hyperbolic Model and Adaptive Disturbance Observer

This paper focuses on the problem of fault-tolerant control for a class of nonlinear systems with unknown nonlinear dynamic. The generalized fuzzy hyperbolic model is used to approximate the unknown nonlinear function. A novel fuzzy adaptive descriptor observer and an adaptive disturbance observer are designed simultaneously to estimate the system state, actuator fault, sensor fault, and disturbance. In this paper, the disturbance is assumed to be generated from an unknown exogenous system. Compared with the existing results, in which the disturbance is generated from known exogenous system, the proposed adaptive disturbance observer is more applicable in practice, since the exogenous system is independent of the controlled system and its parameter matrix is difficult to be measured. Furthermore, using the estimation information, a novel nonlinear dynamic output feedback controller is designed. The controller can stabilize the nonlinear system, which is subjected to the unknown nonlinear dynamic, actuator fault, sensor fault, and mismatched disturbance, simultaneously. Finally, simulation results are provided to illustrate the effectiveness of the proposed techniques.