針對變焦鏡組非線性特性之運動控制設計

Abstract

變焦鏡組被廣泛的應用於軍事上，像是在偵查、警戒、低空觀測等方面，為了獲得高品質的影像和不同的視野，變焦的過程一定要有高速高精度的定位能力。常見的變焦機構分為凸輪機構與直接驅動的導螺桿機構，不論哪一種機構均需要馬達來驅動變焦鏡組作變焦定位，故本研究將關注於變焦系統的伺服定位控制。 由於變焦機構的驅動是由馬達齒輪組所構成，故進行定位控制時將面臨來自於齒輪組與馬達慣性的齒隙(backlash)及死區(dead zone)效應。此兩種非線性效應一直以來是控制工程的一大問題，為了解決此項問題，本研究先將探討分數階微積分的定義，再依此定義將FOPID(fractional order proportion integral derivative)控制器實現在具有非線性效應的變焦機台上。 本研究實驗分成三大部分，第一個部分是針對分數階PI控制器三個控制參數對開迴路系統的影響。第二個部分是比較三種結構上相似的控制器-PID、PDF (pseudo derivative feedback)及FOPID控制，並且從時域與頻域的方面下探討。最後一個部分是針對基於齒隙效應前與基於齒隙效應後的回授訊號控制效能之比較，分析並討論FOPID面對這些非線性效應下所呈現出的系統響應。

The zoom lens is applied popularly in the military, such as detection, low-altitude observation and exploring. In order to get high-performance image and different view, the procedure of zooming must have high speed and precision of position. There are two types of zoom lens mechanisms. One is cam mechanism, another is direct drive mechanism. They are all drived by motor, so the goal of the research is focus on the position control of zoom lens system. The zoom lens system is composed by motor transmission group, which inherent backlash and dead zone effects. The two nonlinear effects are big issues in control engineering.In order to solve backlash and dead zone effects, we use the definition of fractional calculus and apply FOPID (fractional order proportion integral derivative) control into the zoom lens system. There are three parts of the experiments. The first one is analysis the parameter of FOPI control. The second one is comparing the performance of PID, PDF (pseudo derivative feedback) and FOPID control which affect in time domain and frequency domain. In the last experiment, using two different output signals which are inherent and not inherent backlash effect to do the feedback control and discuss the setting time and position error.