Development of Time Varying Sliding Mode Controller with Fuzzy System for Automatic Excavator

Time-varying sliding mode controller(TVSMC) with fuzzy algorithm for an unmanned automatic excavator system is proposed in this paper. Proposed control system is induced from dynamics of 3-link excavator that is boom, arm and bucket. To design the proposed control system, the main structure of controller is based on sliding mode controller(SMC) with time varying sliding surface. In case of TVSMC the robustness of closed loop system can be guaranteed with small chattering but the tracking performance depends on the behavior of sliding surface. Therefore, TVSMC with fuzzy algorithm is proposed in this paper. In the proposed control system, fuzzy algorithm is designed to decide the slop of time varying sliding surface based on the tracking response. As the slop of sliding surface is changed based on the tracking response, a better transient response can be obtained. The proposed control law is applied to the tracking control system of the developed automatic excavator system and the performance is evaluated through experiments.