A Study on the Improvement of Measurement Accuracy of Laser Interferometer using the Kalman filter

칼만 필터를 이용한 레이저 간섭계의 측정 정밀도 향상에 관한 연구

A laser interferometer is the unique measurement device that can measure the range up to a few meters with sub-nano resolution and this characteristic makes it as the important sensing device for the emerging nano-mechatronics technologies. The laser interferometer, however, is very sensitive to the environments such as temperature, humidity, sound noises, vibrations and air turbulences and these factors result in a few hundred nano meter errors. There have been many efforts to reduce these environmental errors. The output of the laser interferometer is assumed to be the sum of a real displacement and a Markov process noise. The purpose of this paper is to develop Kalman filter algorithms to reduce the laser interferometer measurement errors by exploiting the information of displacements in position-servo systems.