Adaptive fuzzy sliding-mode control for motor-toggle servomechanism

An adaptive fuzzy sliding-mode control (AFSMC) design method is developed and is applied to a motor-toggle servomechanism control system. The parameters of the fuzzy rules can be automatically adjusted according to an adaptive law. The main advantages of the proposed AFSMC are that the fuzzy rules base is built by itself and the minimum number of fuzzy rules is used by defining a sliding surface as the input variable. The defined sliding surface includes an integral term which can eliminate the steady state error. The AFSMC is designed through the following steps: first, construct an initial controller based on linguistic descriptions about the unknown plant from human experts; then, develop an adaptive law to adjust the parameters of the fuzzy controller based on a Lyapunov function. Thus the stability of the system can be guaranteed. Finally, the validity of the proposed AFSMC design method is illustrated through the simulations