Benefits of Acceleration Measurement in Velocity Estimation and Motion Control

Abstract

Accurate velocity information is important in various motion control applications. Conventional methods for velocity estimation utilize the measurement of position; for example, the velocity is estimated based on the difference of successive encoder counts or by a model based Kalman filter applied to the encoder output. It becomes a challenge to apply these methods to wide range of working conditions with robustness and accuracy. Recently, a new velocity estimation scheme using an encoder and an accelerometer with a kinematic model, i.e. a kinematic Kalman filter(KRF) has been suggested and applied to linear motor systems. The most attractive feature of the KKF is its robustness to model uncertainty and parameter variations. This paper investigates the performance of the KKF in more detail. It is shown that the KKr can be used with low resolution encoders without significant performance degradation. A reliable and cost effective way of measuring angular acceleration is also suggested using MEMS accelerometers. Experimental results with a low resolution encoder show the superiority of the KKF.