Design of a switching controller for unstable systems under variable disturbance

Abstract

The disturbance in unstable systems can be a challenge for any controller and limits the selection of the appropriate controller. Switching control based on two logic-based switching including fuzzy supervisor and Harris index is proposed regarding to inverted pendulum system as an unstable system under disturbance. The proposed switching method will monitor and control several independent controllers such as SMC, PID and LQR. In the design steps, first independent controllers consist of combination of PID and LQR optimized by BEE algorithm as well as SMC are designed. Second, Harris index is designed that finds most suitable controller among all independent ones. Third, Sugeno-type fuzzy supervisor is also established to monitor Harris index. Innovations of proposed method include the simultaneous use of several different controllers and their advantages in a control loop, reduction of deficiencies of each of the controllers and the improvement of switching operation of Harris index as a switching logic using fuzzy supervisor. Finally, simulation results confirm the desired performance of proposed switching control method.