Advanced precision linear stage for industrial automation applications

In the area of factory automation, accurate positioning systems are increasingly required in various industries to improve the productivity and to lower the manufacturing cost. In this paper, we present a prototype precision linear stage. It has a positioning accuracy of 1 mum and a peak speed above 1 m/s. A permanent magnet dc linear motor has been used in the system as the actuator to eliminate the need for mechanical transmission from the rotary to linear motion. To achieve a fast and accurate closed loop response, we develop a state space predictive controller and a dynamic friction compensation system for the precision stage. The system has been optimally tuned using the genetic algorithm. Some experimental results are presented.