Stability Analysis And Adaptive Reconfigurable Control Of Complex Nonlinear Systems

In this paper, complex nonlinear systems are researched. Using fuzzy adaptive technique, this paper discusses the stability problem and the reconfigurable control problem of the complex nonlinear systems. Combining fuzzy T-S model and adaptive fuzzy logic systems, this paper presents an observer-based fuzzy adaptive control scheme for complex nonlinear systems. Meanwhile, the fuzzy adaptive technique, the robust control technique and the differential-geometry-based feedback linearization theory are synthesized organically, this paper presents an adaptive fuzzy tracking control scheme for complex nonlinear systems. Finally, a fuzzy reconfigurable control scheme is presented for complex nonlinear systems.At first, this paper discusses an observer-based fuzzy adaptive control problem for a class of nonlinear systems. Fuzzy T-S model and fuzzy observer are used to model the nonlinear systems. The adaptive fuzzy logic systems are introduced to eliminate the effect of the modeling errors for the system stability. For the H∞control problem, the control scheme guarantees to stabilize the system fast. For the tracking control problem, the control scheme makes the output of the system track the anticipant signals fast.Further, in order to overcome the disadvantage of the current fuzzy-model-based control design, this paper presents a fuzzy adaptive control scheme for complex nonlinear systems with uncertain nonlinearties and multiple time delays by synthesizing fuzzy T-S model and adaptive time-delay fuzzy logic systems. The fuzzy T-S model is used to model the nonlinear systems. Designing the fuzzy control law by the linear matrix inequalities makes the fuzzy system stable. And then, the adaptive-time-delay-fuzzy-logic-system-based compensator is designed to eliminate the effect of the modeling errors and the uncertainty. This paper discusses two cases: one is that the system state is measurable, the other is that the system state is immeasurable. The H∞control problem and tracking control problem of the uncertain nonlinear systems are solved when the nonlinear uncertainty and the modeling error don't satisfy the matching condition or the constraint condition.Second, combining the adaptive fuzzy control with the adaptive fuzzy identification, this paper presents an improved adaptive fuzzy tracking control scheme for MIMO nonlinear systems. An identifier is designed to identify the unknown part of the nonlinear systems. In the adaptive algorithm, the parameter adjusting laws of the fuzzy logic systems are derived by the tracking error and the identification error. The scheme could fast attain the tracking.Meanwhile, in order to overcome the disadvantage of the fuzzy adaptive technique for researching MIMO nonlinear systems with multiple time delays, an adaptive fuzzy tracking control scheme for nonlinear systems with multiple time delays is presented. In this paper, a kind of adaptive time-delay fuzzy logic systems is constructed and used to approximate the unknown functions with multiple time delays. The disadvantage of making assumptions for the time-delay part is overcome.At last, a fuzzy reconfigurable control scheme is presented for uncertain nonlinear systems. The control scheme is successfully applied to the simulation of fighter control system. The simulation results demonstrate that the control scheme is effective.