H infinity Control for Sandwiched Maglev Stage with Dynamic Damping

An H infinity (H∞) controller for a sandwiched maglev positioning stage is proposed. The maglev positioning stage has a special structure: a sandwiched maglev stage, consisting of repulsive linear motors and attractive linear motors, which have better levitation performance. Forces on the sandwiched maglev stage are analyzed and modeled. The positioning controller is designed based on the feedback linearized model with a dynamic damping system. The design of the H infinity controller for stage positioning is derived as a series of linear matrix inequalities (LMIs) which are efficiently solved in Matlab. The proposed controller and its effectiveness is demonstrated compared to PID method.