Estimation of Friction and Spring Characteristics of a Variable Displacement Pump using the Extended Kalman Filter Approach

抄録

Extended Kalman Filter (EKF) is used to estimate friction and spring characteristics on the swash plate of a variable displacement pump. In earlier studies, the feasibility of the approach was established using simulation studies to establish limits of accuracy for the EKF approach when applied to an ideal situation. In this study, the EKF is applied to an experimental system and the issue of reliability in estimation of certain pump parameters is addressed. In addition, an approach to assign values to accommodate convergence of the EKF is considered. A special experimental system was set up to facilitate the measurement of certain states to enhance the EKF approach. Estimated parameters did show some scatter about a specified operating point but in general, were reasonably repeatable. Good control over operating conditions was absolutely essential for repeatability. The study also showed that changes in the system parameters could be accurately tracked.