A variable speed-displacement control with virtual load sensing structure for energy conservation of positive flow excavator

In this paper, a variable speed-displacement control with virtual load sensing structure is proposed to reduce the energy loss caused by the difference between supply and demand while ensuring that the engine is at its optimal economic operating point. The virtual load sensing structure is implemented by the controller to distribute the output of the positive flow pumps to adjust the operating point of the engine and maintain the original maneuverability of the excavator. The energy-saving control parameters of the positive flow excavator are determined based on the experiment and the mathematical models are built to analyze the energy coupling between critical components. The simulation and the experimental results show that the proposed control strategy can maximize the energy efficiency without adding any energy storage devices, which reduces the energy consumption by 4.8%–12.19% under different load pressure conditions for the XCMG XE215 type positive flow excavator.