Induction motor servo system using variable structure control with fuzzy sliding surface

Sliding mode control has been widely used in induction motor servo drives. It provides attractive features such as fast dynamic response, insensitivity to variations in plant parameters and external disturbance. However, one difficult problem, which has meant that the sliding mode controlled servo system has not yet become popular, is due to chattering. This paper presents a new fuzzy-sliding mode controller for a vector-controlled induction motor servo system not only to guarantee the stability of the system but to practically eliminate the chattering problem. The performance of the proposed system is compared with that of traditional sliding mode control and sliding mode control with boundary layer method.