Adaptive fuzzy position controller for induction servomotor drive using sliding-mode technique

An adaptive fuzzy sliding-mode control (AFSMC) system with an integral-operation switching surface is adopted to control the rotor position of an induction servomotor drive. The AFSMC system comprises the fuzzy control design and the hitting control design. In the fuzzy control design, a fuzzy controller is designed to mimic a feedback linearization (FL) control law. In the hitting control design, a hitting controller is designed to compensate the approximation error between the FL control law and the fuzzy controller. The tuning algorithms are derived in the sense of the Lyapunov stability theorem, thus the stability of the control system can be guaranteed. Moreover, to relax the requirement for the approximation error bound, an error estimation mechanism is investigated to observe the approximation error bound in real-time. Experimental results verify that the proposed control systems can achieve favorable tracking performance and that they are robust with regard to parameter variations and external load disturbance.