H∞ Robust Control of a Novel Magnetic Levitation Stage

In this paper, a novel magnetic levitation stage (MLS) is proposed. In the MLS, the moving plate is driven by Lorentz force that acts on Halbach arrays by AC windings, and the plate is levitated by hybrid interaction between DC coils and permanent magnets and between AC windings and Halbach arrays. The driving principle of the MLS is described. The dynamic model of the MLS is analyzed and constructed. Then, a H∞ robust controller is designed to realize the precision positioning and robust stability of the MLS due to parametric uncertainty and external disturbances. Finally, the motion control of the MLS is simulated. The simulation results show that the designed H∞ robust controller can obtain superior precision, robust stability and good ability against disturbances. Thus it is concluded that H∞ robust controller is suitable for the precision positioning control of a magnetic levitation stage.