本論文提出一套新穎的光學量測技術-反射式準共光程外差光柵干涉儀,並將這套干涉儀應用於長行程精密定位。準共光程的光路設計,提高了外差光柵干涉儀的穩定度。本系統使用反射式的光柵,使得量測系統容易架設於各種位移平台,並容易模組化。本研究設計一套類比電路來解調外差訊號,增加量測相位的速度並降低系統成本。接著利用反射式準共光程外差光柵干涉儀作為位置回授系統,進行長行程精密定位技術的開發。將具有長行程移動能力的壓電陶瓷馬達,以及具有精密定位能力的壓電致動器,組合成一組位移平台,使位移平台同時具備長行程及精密定位的能力。此外我們利用比例回授控制器,對此位移平台進行閉迴路控制。本論文所提出的反射式準共光程外差光柵干涉儀的理論解析度為0.2nm。考慮雜訊的影響下,本系統的量測解析度為4nm,量測速度為500?m/s。而定位解析度為5nm,定位速度為286?m/s. A novel optical displacement measurement system “Reflective quasi-common path heterodyne grating interferometer”was proposed. The nearly common path configuration increases the stability of heterodyne grating interferometer. We design an analog circuit to demodulate the heterodyne signal to increase the measurable speed and decrease the cost of the system. In this research, the reflective quasi-common path heterodyne interferometer is used as a displacement feedback system to feedback control a stage. The moving stage is composed of a coarse stage and a fine stage. The coarse stage is used for long-distance positioning while the fine stage is used for precision compensation. The coarse stage and fine stage is integrated and can provide long-distance movement with nanometric resolution. We use the proportional controller to compensate the error simultaneously. Theorically, the resolution of the reflective quasi-common path heterodyne grating interferometer is 0.2nm. After taking the noises into consideration, from the experimental results, the resolution of the interferometer is 4nm. And the measureable speed is 500?m/s. The positioning resolution is 5nm and the positioning speed is 286?m/s.