Development of Position Control for an Active Pneumatic Isolation Table System via High Speed on/off Valves

• Main Authors: Tsu-Wen Ma, 馬祖文
• Other Authors: 江茂雄
• Format: Others
• Language: en_US
• Published: 2010
• Online Access: http://ndltd.ncl.edu.tw/handle/88866006955479016608

碩士 === 臺灣大學 === 工程科學及海洋工程學研究所 === 98 === This study aims to develop the position control of an active PWM (Pulse Width Modulation)-controlled pneumatic isolation table system. A novel concept using parallel dual-on/off valves with PWM control signals is implemented to realize active control and to improve the conventional pneumatic isolation table that supported by four pneumatic cushion isolators. In this study, the cushion isolators are not only passive vibration isolation devices, but also pneumatic actuators in active position control. Four independent closed-loop position feedback control system are designed and implemented for the four axial isolators. In this study, on/off valves are used, and PWM is realized by software. Therefore, additional hardware circuit is not required to implement PWM and not only cost down but also reach control precision of demand. The study first derives the nonlinear time-variant mathematical models of single-axial pneumatic isolation system and then simplifies the models as a 3rd system. In the controller design, the Fourier series-based adaptive sliding-mode controller with H-infinity tracking performance is used to deal with the uncertainty and time-varying problems of pneumatic system. The open-loop and closed-loop dynamic simulations are implemented by MATLAB to verify the feasibility of the proposed system and controller. Finally, the experiments on the pneumatic isolation table system for synchronous position and trajectory tracking control, including no-load and loading conditions, and synchronous position control with master-slave method are implemented in order to verify that the controller for each cushion isolator can realize good position and trajectory tracking performance.