Hybrid Coarse and Fine Controller Tuning Strategy for Magnetic Levitation System

Abstract

The magnetic levitation system requires a finely tuned controller to suspend a ball in the air. Any imbalance in the force balance condition might result in high fluctuations causing the ball to fall out of levitation. A hybrid tuning strategy based on successful levitation and minimization of vibrations has been designed and tested in real time. The proportional–integral–derivative controller has been tuned in two stages. The parameters of the controller have been calculated by the traditional pole placement technique for coarse tuning and evaluation of bounds. Nature-based non-traditional optimization techniques have been used to minimize the integral of the absolute error within this threshold limit for finer tuning. This novel strategy has been employed to find the best combination of the controller parameters such that levitation is ensured by coarse tuning and error is minimized by fine tuning. Real-time robustness analysis has also been done by means of rejection of external disturbance induced manually in the levitated stage.