Study of chattering suppression for the sliding mode controller of an electromagnetic levitation system

Due to the inherent non-linearity and open-loop instability of maglev systems, their high-quality control performance is critical in the development stage. Sliding mode control has great potential in the field of maglev vehicle control because of its superior control performance, robustness and interference resistance. In practical applications of sliding mode control, however, the limitations of the hardware physical properties and time delay of the control units of maglev systems can cause chattering, thereby significantly reducing the stability of maglev vehicles. In order to suppress chattering, a modified sliding mode controller that combines the exponential reaching law and continuous control laws is proposed in this study. A single-point levitation experimental platform and corresponding co-simulation model were built, and a parameter influence analysis of the modified sliding mode controller was conducted. This paper presents an adaptive correction method for the sliding mode control parameters based on the aforementioned chattering study. The actual levitation experiments were used to validate the control performance of the proposed controllers. Overall, the conducted research revealed that the modified controllers could effectively suppress chattering and possess excellent robustness.