壓電衝量驅動機構之運動行為研究

Abstract

壓電致動器為一種效率高的微定位驅動元件，具有高解析度及反應快速的優點，衝量驅動機構用三角波輸入來驅動質量塊的速度以產生穩定的步進運動。本論文提出了一個簡明的衝量模型來解釋此運動行為，該衝量模型以三角波之頻率與責任週期作為輸入，以估計機構的運動行為及步進距離，並以進階的動態模型及實驗結果驗證該衝量模型的有效性，而在論文中也討論了動態模型中壓電致動器伸長量與驅動電壓間的遲滯現象。論文最後實現出一個三自由度平面衝量驅動機構來做長行程的定位，並以實驗比較所推導出來的動力學模型其數值模擬結果。光學實驗設備測量出此三自由度平面衝量驅動機構可達到小於1微米定位且衝擊力所產生的速度可達到10毫米/秒以上，因此一個設計適當的衝量驅動機構可適合平面精密定位，如光學顯微鏡及生物醫學上之應用。

Piezoelectric actuators are efficient drivers for micro-stepping mechanisms, with advantages of high resolution and rapid response. A stable stepping motion from mechanical excitation of a piezoelectric device is generated using the impact drive mechanism (IDM) based on various triangular waveforms exerted by the counter mass speed. The dissertation proposes a concise impulse model to describe stepping motion behavior. The impulse model incorporates the duty ratio and input frequency of the triangular waveform as the system inputs and outputs the estimated step size and behavior of the stepping motion. An enhanced version of the dynamic model and our experimental results validate the efficacy of the impulse model. A hysteresis phenomenon between the elongation of actuators and excited waveforms is also estimated for the dynamic model. Lastly, this study examines a 3-DOF planar IDM for large travel positioning. Numerical simulations of the planar dynamics are derived and compared with experimental results. Experimental results obtained with optical equipments demonstrate a positioning step size of less than 1 □m with an impact velocity above 10 mm/s. An adequate design of IDM motion is highly promising for use in planar precision positioning, such as optical microscopy and biomedical application.