Abstract：There is tight electromagnetic and mechanical coupling among planar motor (PM) 6- degree of freedom (DOF) motions for photolithography in semiconductor manufacturing. For the purpose of achieving decoupling control of the 6-DOF motions, this paper presents the current-controlled model of linear motor (LM) as the actuators, the concept of the actuator forces and the modal forces, and the decoupling dynamics model based on the modal forces. Under some reasonable assumptions on the prototype motor kinematics and structure parameters, the modal forces method successfully decouples the 6-DOF kinetics models and all the kinetics models become simple 2nd order linear systems which can be controlled with multiform linear controllers. For the prototype motor, the transformation matrices between the modal forces and the actuator forces are derived and the system control block diagram is presented. At last the PD(Proportional-plus-Differential) controller is designed for the purpose of X position control and the feasibility analysis about the modal force method is done.
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2009, Vol. 24 
