Development of a Precise and Low-Cost Positioning Stage Using a Two-Loop Robust Controller

• Main Authors: Chun-Chu Su, 蘇春菊
• Other Authors: 顏炳郎
• Format: Others
• Language: zh-TW
• Published: 2009
• Online Access: http://ndltd.ncl.edu.tw/handle/g494tx

碩士 === 國立臺北科技大學 === 自動化科技研究所 === 98 === In this research, we implemented a low-cost precision positioning stage which using a commercial available OPU (optical pickup-head unit) by a two-loop controller. A two-loop controller described in this research is proposed by adopting a disturbance observer (DOB) as the internal-loop compensator to cancel out the model error and a H-infinity as external-loop compensator to provide sufficient stability robustness for the entire system. The feedback position signal of the platform was measured through the reflected signals on photodiodes from a compact disc. Experimental results showed that the positioning stage was able to follow different ranges of step commands, such as 1 and 200 step commands. H-infinity controller has superior features for frequency shaping to obtain a sufficient stability margin to adapt an internal-loop DOB with higher bandwidth. This explains why the H-infinity control with DOB can achieve better performance.