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    Please use this identifier to cite or link to this item: http://ir.lib.ncu.edu.tw/handle/987654321/2463


    Title: 適應性光學之系統鑑別;System Identification of Adaptive optics
    Authors: 張智強;Chih-Chiang Chang
    Contributors: 機械工程研究所
    Keywords: 可調面鏡;移相干涉術;系統鑑別;適應性光學;deformable mirror;System ID. PSI;Adaptive optics
    Date: 2004-06-18
    Issue Date: 2009-09-21 11:47:36 (UTC+8)
    Publisher: 國立中央大學圖書館
    Abstract: 適應性光學(adaptive optics)是使用可調變的主動式光學元件(active optical device),配合上波前感測器(wavefront detector),經由控制器即時地去補償修正因外在擾動造成波前改變的系統,其在天文科學及國防上已被大量研究與應用,於通訊、生醫與工業雷射銲接加工等領域上也開始受到重視。 適應性光學系統主要包含三個部份:波前感測(wavefront sensing)、波前的修正(wavefront correction)與補償控制系統(reconstruction and control system)。本論文主要規畫之前饋式控制(feedforward control)適應性光學系統之實驗部份,包括光電元件製作、架設與完成系統的鑑別一一做討論。在波前感測方面,利用Mach-Zehnder干涉方式,配合液晶裝置(liquid crystal device,LCD)做移相干涉術(phase-shift interferometry, PSI)將相位偵測出來。利用PSI做相位的重建有較好的效果,並且也完成LCD驅動電路以及提出一相位找尋的方法與快速切換的方式。而波前偵測器部份我們使用光二極體陣列(photodiode array)與電荷耦合元件(charge couple device,CCD)分別做測試比較空間的解析度與取樣速度。在波前修正部份利用可調變聚焦鏡(deformable mirror,DM)配合自製的多通道驅動器,可改變不同通道的電壓值去作波前的修正。控制器部份則分別比較個人電腦(personal computer,PC)與數位訊號處理器(digital signal processor,DSP)做控制器的不同。 最後,利用前述兩部份完成1 Hz的前饋式系統之系統鑑別(system identification),討論單一輸入單一輸出(single-input & single-output)的系統關係,並對各部份的頻寬限制與改善做一探討與說明。 Adaptive optics is used to compensate the distortion through external disturbance by using adjustable optical devices and wavefront sensors. It already exists many applications and research, in astronomy and military defense. Moreover, it gradually attracts an attention in communication, bioelectronics and laser welding. Adaptive optics consists of three parts which are the wavefront sensing, the wavefront correction and the reconstruction and control system. An adaptive feedforward control is adopted to compensate the wavefront distortion in our setup. In the wavefront sensing, the photodiode array circuits and the LCD driving circuits are accomplished. We propose a new method to find the LCD phase shift voltage and test the response time of the LCD. Also, a Mach-Zehnder interferometer with LCD using PSI is setup to reconstruct the phase distortion by using photodiode array and CCD camera. In the wavefront correction, deformable mirror driving circuits is accomplished and the channel coupling effect of the deformable mirror is analyzed. In control system, we develop an enbedded DSP system as a controller and compare the performance with a PC. Finally, we identify the feedforward system model of single input and single output system at 1 Hz, and we discuss the dynamic ranges of the overall system.
    Appears in Collections:[Graduate Institute of Mechanical Engineering] Electronic Thesis & Dissertation

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