Nonlinearity Compensation of an Angular Position Encoder Using a Compact Linearization Circuit

This paper presents a compact linearization circuit designed to compensate for the nonlinearity of an angular position encoder. The circuit comprises two main sections: a preprocessing circuit that generates a modified sine signal from the encoder output signals, and a two-stage piecewise linear analog-to-digital converter of a compact design that performs nonlinearity compensation and digital conversion of the modified sine signal. Compactness is achieved by utilizing a single flash analog-to-digital converter for both conversion stages, thereby reducing the number of power-consuming comparators and production costs. LabVIEW simulations demonstrate a major reduction in both the maximal absolute nonlinearity error and the relative nonlinearity error of the measurement system. Before linearization, these errors were 0.33067 rad and 21.05%, respectively, but decreased to 0.00654 rad and 0.10403% after linearization with the proposed circuit.