Fuzzy Adaptive Fault-tolerance Control For A Class Of Uncertain Nonlinear Systems

In this dissertation, fuzzy logic systems is used as a tool, combined fuzzy logic systems, sliding mode control, adaptive control, H∞control, we make a study of designing fuzzy adaptive fault-tolerance control architecture for some kinds of uncertain systems. Global asymptotic stability is established in the Lyapunov sense, with the tracking errors converging to a neighborhood of zero. The simulation results verify the effectiveness of proposed control algorithm.This dissertation's main contributions as follows:1. Direct and indirect fuzzy adaptive fault-tolerance control architecture is proposed for a class of SISO nonlinear dynamic systems which concludes actuators fault. The architecture employs fuzzy logic systems to approximate nonlinear unknown function which concludes fault function, uses fuzzy sliding controller to compensate for the fuzzy approximation error, through altering the structure of controller compensate for the influence due to actuators fault. Global asymptotic stability is established in the Lyapunov sense, with the tracking errors converging to a neighborhood of zero. The simulation results verify the effectiveness of proposed control algorithm.2. The observer-based adaptive fuzzy fault-tolerance controller is developed for a class of SISO uncertain nonlinear systems which concludes actuators fault that is unknown. The controller has H∞tracking performance. It is proved that the proposed control algorithm guarantees the system stability and maintains a good tracking performance as well. The simulation results verify the effectiveness of proposed control algorithm.3. On the basis of study of SISO control plant, two kinds fuzzy adaptive fault-tolerance control schemes are proposed for MIMO uncertain nonlinear systems. One is adaptive sliding fault-tolerance control with full state which concludes fuzzy logic systems, sliding mode control, adaptive control; another is fuzzy control with full state which concludes feedback linearization, fuzzy logic systems, H∞control. Global asymptotic stability is established in the Lyapunov sense, with the tracking errors converging to a neighborhoodof zero. The simulation results verify the effectiveness of proposed control algorithm.