Improving Position Sensor Accuracy Through Spatial Harmonic Decoupling, and Sensor Scaling, Offset, and Orthogonality Correction Using Self-Commissioning MRAS Methods

Abstract

This paper presents methods for improving the accuracy of vector-based position measurements through the decoupling of multiple nonideal sensor properties using model reference adaptive system (MRAS) techniques. The nonideal sensor properties considered are: signal scaling errors (amplitude imbalance on the vector components), signal offsets, imperfect orthogonality (quadrature error) between sensor vector components, and additional spatial harmonics superimposed on fundamental sensor outputs. Simulation and experimental results are provided to evaluate the proposed MRAS-based decoupling methods. The methods presented here can be applied to multiple forms of vector-based position measurement and estimation such as the use of magnetoresistive sensors, sine/cosine encoders, resolvers, or self-sensing (sensorless) methods. These methods can be implemented in real time and are well-suited to the self-commissioning of vector-based position sensors for enhanced sensor accuracy.