三層多晶矽微交叉連桿機構與梳狀致動器之動態分析

Abstract

本論文主要在以三層多晶矽製程方法之架構下,設計一由梳狀致動器推 動微交叉連桿之微機電系統.我們分析梳狀致動器的特性及微交叉連桿機 構的運動方程式,以得到梳狀致動器在驅動一複雜機構時的動態模式,與進 行控制的可能性.首先,我們介紹三層多晶矽製程方法及設計上的規範.其 次,以虛功原理推導梳狀致動器的靜電力,並與一平行板致動器比較.再由 材料及結構的特性計算出致動器的彈性係數及自然頻率,以得到其等效運 動方程式.我們亦分析梳狀致動器附著的現象,並推導其驅動電壓及位移的 限制.接著,由分析微交叉連桿機構的拘束以得到其運動的微分幾何方程 式.最後,合併致動器的運動模式,我們模擬微交叉連桿致動系統的運動軌 跡及暫態響應,並嘗試以PID控制器改善其響應. A lazy-tongs microstructure with comb-drive actuator is designed and fabricated by three-layer polysilicon process. Virtual work principle,mechanics of material and Rayleigh method are used to evalute the drivingforce, spring constant, and vibration frequence of comb-drive actuator.The sticking phenomenon also restricts the driving voltage and displacement. The dynamics of lazy-tings microstructure is derived from the differential-algebraic equation. We introduce PID controller and simulate the close-loopof structure combining comb-drive actuator. The numerical integration is modified by Baumgarte method. Results of simulation prove that under proper control the whole system not only presents good dynamic response but also provides exact position.