Dynamic Analysis and Improvement of the Electrohydraulic System under Power Limitation Control

Abstract

With the electronization process of mobile hydraulics moving forward, the basic demand of power limitation control is increasingly fulfilled by electronic pump controllers to replace hydro-mechanical regulators. However, the nonlinear power controller introduces additional dynamics and potential oscillations into the electrohydraulic system. In this paper, the dynamic performance of the electrohydraulic system is analyzed using the linearized mathematical model and root locus tool, considering the factors of pump dynamic, actuator dimension, power setting point, and so on. A pump-based virtual leakage compensator is designed to reduce oscillations due to low damping excited by the power controller. The stability and parameter selection are then discussed to obtain optimal dynamic behavior. Using the traditional power controller as a comparison, the boom lifting motion test of a 2-ton excavator was carried out to validate the proposed compensator. The test result indicates that the proposed controller with optimized parameters has the ability to suppress pressure fluctuations and velocity oscillations.