Dynamic modeling, controller design and experimental validation of a planar motion stage for precision positioning

This paper discusses dynamic modeling, controller design and experimental validation for development of a three degree of freedom (DOF) planar motion stage for precision positioning in the XY directions. A model of the stage dynamics was first identified for the purpose of controller design using the results of step response tests. A proportional integral derivative (PID) feedback control with disturbance observer was then designed and implemented using an analytical method. We discuss the policy for PID controller tuning to achieve the most desirable performance. In addition, a feed-forward control consisting of a simple predictor was added to reduce tracking error. Experimental results show that the developed controller provides fast positioning with less tracking error than a simple PID controller and is suitable for precise positioning of multi-DOF stage system. (c) 2005 Elsevier Inc. All rights reserved.