Abstract:Permanent magnetic levitation system is a typical nonlinear system. As the air gap between the magnetic conductor and suspension changes, the control characteristics change which affects the stability of the system. In order to prevent the external interference from causing the suspended matter falls or adsorbs on the magnetic conductor, as the system deviating from the equilibrium point. An antifall and antiadsorption control method based on air gap variation is proposed. The multiplepoint preset levitation force is selected in the entire suspended air gap, the control parameters are calculated based on the preset levitation force of each design point, and the complete antifall and antiadsorption control law is obtained according to the interpolation principle. This method can effectively compensate for the uneven variation of levitation force, and improve the controllability, stability and robustness of the system. Simulation and experimental results show that the antifall and antiadsorption control method can mitigate impact and improve antifall performance. When the air gap is enlarged by the external disturbance, the levitation force increases rapidly to prevent the suspended object from falling. When the external disturbance causes the air gap to become smaller, the levitation force rapidly becomes small, and the suspended matter is prevented from being adsorbed on the magnetic conductors.