Adjacent Cross-coupling Control for Magnetic Levitation System with Ultra-local Sliding Mode Algorithm

For multi-point magnetic levitation systems (MMLSs), cooperative control is crucial, as inconsistent disturbances to each levitation point (LP) will result in control failure of the entire system. Therefore, to enhance the overall disturbance-resisting performance of the MMLS, this paper proposes an ultra-local sliding mode adjacent cross-coupling controller (USMACC). First, a general model of the MMLS is established. The coupling relationship between LPs is deduced considering the composite motion of the system centroid. Then, an ultra-local sliding mode controller (USMC) is designed, which eliminates the parameter dependency of an accurate system model and possesses excellent dynamic performance for each LP. Next, adjacent cross-coupling control (ACC) is integrated into USMC, effectively reducing tracking errors of each LP and synchronization errors between LPs. Last, comparative experiments with conventional PID and USMC demonstrate that the MMLS adopting the proposed USMACC possesses exceptional overall disturbance-resisting performance under various inconsistent external disturbances.