| 摘要: | 雖然電力驅動的馬達應用的範圍非常廣泛，從小型的光碟機讀寫頭與照相機機械式變焦鏡頭馬達，至大型的CNC 驅動、電梯傳動與機械手臂等。然而在具有高密度粉塵、油氣以及瓦斯等易燃、易揮發氣體，不允許有火花產生導致燃燒爆炸可能性的工作環境下，一般的電動馬達的應用便受到限制。雖然仍有一些特殊的防爆型電動馬達可能適用，然而在經費與安全性的考量下，氣動馬達提供了另一種應用的可能性。不同於氣壓缸須要較大的空間(一般而言約為行程的兩倍) ，空氣馬達體積小且造價低廉，因此漸漸被應用在工業機械上。以往的氣動馬達往往被應用在精度要求較低的自動化機械上(如汽車修理廠、氣壓平台、氣動門等)，較少應用於高精密度的產業機械上，也較少有此類的學術論文發表。近年來由於成本與環保的考量，氣動馬達越來越受到重視，因此本計劃將針對氣動馬達應用於高精密XYZ 平台上所遇到的問題進行研究。由於空氣的可壓縮性、供氣氣壓的變化不確定性及空氣流路的複雜性，氣動馬達內與管路的空氣流體動力學在精密控制上，將扮演著重要的角色，因此本計劃首先將針對空氣動力學進行數學與電腦程式分析，以期得到準確的動力方程式(dynamic equations)，同時可以了解整體系統模型的誤差來源與範圍(uncertainty bound)。本計劃的第二的主題將根據所推導出的動力方程式與模型誤差範圍，設計出強健性順滑控制器來達到精密控制的目的。目前本研究室已改裝一組XYZ 平台，並可準確地單軸的運動速度。然而由於氣壓不穩定與摩擦力等因素，多軸精密定位控制仍是值得研究的課題。因此本計劃將設計強健性的順滑控制器，並將其實際應用在XYZ 平台。 ; Nowadays, air motors are widely used in the automation industry due to special requirements, such as spark-prohibited environments, the mining industry, chemical manufacturing plants, and so on. Unlike pneumatic cylinder usually requiring almost twice the space to install on the machine, the air motor is compact and more adaptable to the machine’s structure. Hence, air motors have been applied to more and more industrial machines. However, during past decades, air motors are mostly selected to work on low-precision machines due to their difficulties for precision control. Since the need of high precision air motors has become more and more popular, we plan to work in this proposal on the precision control for the vane-type air motor and its application on XYZ table. Due to the compressibility of air and the friction in the mechanism, the overall system is nonlinear with hysteresis behavior. The performance of the previous controllers implemented on the air motor system demonstrated a large overshoot, slow response and significant fluctuation errors around the setting points. In order to obtain high precision control, the fluid dynamics of with the pipes and the air motor need to be studied. Hence, the first goal of this project is to analyze the fluid dynamic model both through the mathematical and numerical tools. Based on the analysis, the uncertainty of the system can be classified and their upper bounds can be estimated more precisely. Although we had replaced the electrical motor on a XYZ and obtain good performance in velocity control, the difficulties of position control are much higher due to the friction of the mechanism and the compressibility of the air. Hence, in the second year, we will develop a robust sliding mode controller for the air motor driven XYZ table. ; 研究期間 9808 ~ 9907 |
