Since the energy crisis, the further development of a variable speed pump-controlledhydraulic system driven by an electric machine has attracted increasing attention during the pastfew years. As a response to this, an innovative double pump-controlled asymmetric cylinder system(DPC) and its control method are proposed in this study. The purpose of this study is to investigatethe performance of two variable speed pump-controlled systems for asymmetric cylinders under afour-quadrant operating condition, in comparison with single pump control (SPC). The four-quadrantoperating principles of the two systems are analyzed by simulation. Simulation models for bothsystems are introduced, and a position control method is proposed, with a tracking dierentiatorand speed feedforward, plus proportional-integral-derivative (PID) for four-quadrant operation.The DPC model was validated with the measurement of a crane. The simulations using the validatedmodel were performed with a position reference and a varying load (four-quadrant operating arm ofan excavator). The results demonstrated that the velocity fluctuation is eliminated by using the DPCinstead of the SPC, and the position control performance of the DPC is better compared to the SPC,although the energy eciency decreases slightly. Hence, the proposed DPC and its position controlmethod are feasible for the four-quadrant operation of asymmetric cylinders.

Control and Performance Analysis of Variable Speed Pump-Controlled Asymmetric Cylinder Systems under Four-Quadrant Operation PDF

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