Study on energy efficiency characteristics of the heavy-duty manipulator driven by electro-hydraulic hybrid active-passive system

Multi-joint heavy-duty manipulators, such as working devices of hydraulic excavators, are mostly driven by hydraulic cylinders. Poor energy efficiency of the hydraulic system results in serious energy waste. In this paper, a novel electro-hydraulic hybrid driving (EHHD) system consisting of an electrically active driving system and a hydraulically passive driving system is presented to cope with the special operating characteristics of the heavyduty manipulator. In the research, a co-simulation model of the proposed system is established, and the key parameters are designed through simulation. On the basis, a test prototype was established to verify the effectiveness and energy efficiency of the proposed system. The results prove that, compared with the popular loadsensing system, the energy consumption in one cycle of boom lifting and lowering process is reduced by 70%.