Proposal of Position Reconstruction with Polynomial Fitting Approach for Precise Motion Control

Optical encoders are extensively used for position measurements in motion control systems. The inherent quantization feature of encoders limits the control performance in many applications. This paper shows a way to reconstruct the smooth position signal from the quantized measurements. The method uses a polynomial fitting approach where the degree of polynomial is automatically selected via a convex optimization method. In addition, the information of the plant is exploited by combining an observer. The effectiveness of the proposed method is verified by simulations and experiments using a high-precision linear stage.