Robust adaptive Kalman filtering for nonlinearity compensation in laser interferometer

In this paper, we propose a robust adaptive Kalman filter design for the dynamic nonlinearity compensation in the heterodyne laser interferometer expressed by a state equation with the parameters uncertainty. The interferometer's measurement process is modeled to improve the displacement precision. The adaptive factor is adopted to tune the covariances of process noise and measurement noise. Through the comparison of experimental results with those obtained by a capacitance displacement sensor, it is proved that the robust adaptive Kalman filter can improve the robustness of the system and the accuracy of the displacement measurement in real time.