Real-time precision displacement measurement interferometer using the robust discrete time Kalman filter

This paper proposes a robust discrete time Kalman filter (RDKF) for the dynamic compensation of nonlinearity in a homodyne laser interferometer for high-precision displacement measurement and in real time. The interferometer system is modelled to reduce the calculation of the estimator. A regulator is applied to improve the robustness of the system. An estimator based on dynamic modelling and a zero regulator of the system was designed by the authors of this study. For real measurement, the experimental results show that the proposed interferometer system can be applied to high-precision displacement measurement in real time. (C) 2004 Elsevier Ltd. All rights reserved.