NON-PDC OBSERVER-BASED T-S FUZZY TRACKING CONTROLLER DESIGN AND ITS APPLICATION IN CHAOS CONTROL

In many mechanical devices with chaotic behavior, stabilizing unstable periodic orbits (UPOs) of the system has positive effects in the lifetime and effectiveness of these devices. In this study, a new non-parallel distributed compensation (non-PDC) observer-based tracking controller is presented for Takagi-Sugeno fuzzy systems to control the chaotic behavior of such systems. Asymptotic stability synthesis of the closed-loop system is investigated using a fuzzy Lyapunov function to derive less conservative conditions than common quadratic Lyapunov function-based approaches. To tackle the main drawback of the fuzzy Lyapunov-based approaches, which assume some upper bounds on the derivatives of the fuzzy grade functions, we propose a new procedure by considering a constraint on the control signal. The new design conditions are given in the form of linear matrix inequalities (LMIs). The proposed control structure is applied to spinning disks in which chaos phenomena appear in lateral vibration. Simulation results are given to show the applicability of the proposed tracker to the UPO problem.