PRACTICAL CONTROLLER FOR PRECISION POSITIONING SYSTEM - A NEW DESIGN APPROACH AND APPLICATION TO MECHANISM WITH FRICTION

摘要

A variety of precision positioning system, such as machine tools, measuring machines and semiconductor manufacturing systems, generally require high performance motion controllers. For this account, a practical controller which provides simple and transparency design and structure; produces fast response, nearly zero overshoot, high robust performance and excellent accuracy is required, especially in industry. Industry has favored classical controllers such as PID, due to their structure simplicity and well-known characteristics. However, the classical controllers have met limitations when a higher positioning performance becomes more stringent and high robust characteristics are required. Many advanced controllers have been devoted to solve these problems, such as robust controllers with disturbance observer, time-optimal controllers, adaptive robust controllers, sliding mode controllers, and advanced intelligent controllers. Even though those advanced controllers are capable to gain performances satisfied in robustness of precision positioning, determination of known model parameters of the plant and sufficient knowledge of control theory in their design procedure are necessary. The performance of those controllers are based on how accurate the known model and known parameters are used in their design procedures. Their design processes are time-consuming and much labor is needed to identify its parameters. It is a difficult task for operators who are unfamiliar with advanced controllers. In industry application, these advanced controllers are often impracticable.