MODELING AND CONTROL PARAMETER DETERMINATION FOR LINEAR PIEZOMOTOR POSITIONING STAGE

摘要

A novel linear piezomotor positioning stage system has been developed. A three degree-of-freedom dynamic model is established to simulate its motion characteristics. The model considers the varying stiffness and damping at the interface between the linear piezomotor and its guideway, and takes the piezomotor-stage coupling effect into account, which makes the dynamic modeling more realistic and practical. In addition, this study applies the objective contours control method to the parameter determination of a PID controller to optimize the system performance. Without the application of the PID controller, the system shows its settling time of 80 ms, overshoot of 50% which are improved to less than 40 ms and 5%, respectively, with the effective use of the controller. The positioning performance predicted based on the model is verified in an experimental study. It turns out that the model can precisely predict the motion characteristics of the linear piezomotor positioning stage system. The methodology developed in this study can be used to improve the motion performance of the existing positioning systems for higher accuracy, nanometer resolution, and quicker response, as well as to help design and develop new positioning systems.