Analysis and control for mictomotion stage based on magnetic suspension technology

A novel contact-free micromotion stage based on magnetic suspension technique is proposed. In this micromotion stage, a moving plate is driven by Lorentz force that acts on four groups of halbach arrays by AC windings. And the plate is levitated by magnetized force that acts on four electromagnets by DC coils. Namely the designed stage is driven by DC-AC hybrid actuation. This paper deals with analysis of the actuator with halbach arrays on the basis of the analytical two-dimensional field solutions and predicts magnetic field, thrust and flux linkage. The results are validated by comparison with finite element analysis. A dynamic equation and a strategy of controlling are obtained by the analysis. A H∞ robust controller of the micromotion stage due to parametric uncertainty and exogenous disturbances is constructed. And the simulating results show that the H∞ controller is robust stable for the modeling perturbation and has excellent anti-disturbance ability, that micromotion stage is reliable and precision. Through comparison with PID, the H∞ controller has higher precision. Thus the constructed H∞ robust controller of the micromotion stage is effective and suitable.