Abstract: The rapid development of intelligent manufacturing and stringent demands for energy conservation have put forward much higher requirements for electro-hydraulic systems, which should not only achieve high control precision but also work in a highly energy-efficient way. Actually, with the existing techniques it is not difficult to achieve single objective, i.e., high precision or high efficiency; what is really challenging is achieving both objectives simultaneously. This study is derived from the practical requirements for high precision and high energy efficiency. In the beginning, the related studies are reviewed from two aspects, i.e., hydraulic circuit configuration and system control design. Then, oriented for simultaneous achievement of high precision and high efficiency, the parallel-connected pump-valves coordinated electro-hydraulic system is proposed, and it is compared with the commonly used systems in this field. To track the given velocity trajectory with high precision, the system controller is synthesized based on the desired compensation adaptive robust control. The tracking performance and stability of the closed-loop system are analyzed in theory. Finally, the comparative experiments are conducted and the results show that the proposed system can achieve not only the same level of high tracking precision as the typical valve-controlled system, but also a high level of energy efficiency.

Key words: fluid power transmission and control, pump and valve coordination, motion control, energy saving