Research On Control Method On Energy Recovery And Reuse Of Hydraulic Hybrid Excavator

In view of the existing hydraulic hybrid excavator insufficient, an inproved hydraulic hybrid powertrain system is designed for hydraulic excavator and a torque coupling hydraulic hybrid excavator trial platform is developed, to further reduce the energy fuel consumption, and to improve the stability of boom lowering. This paper mainly gains following progress:1) A hydraulic excavator energy consumption optimization method is proposed, which utilizes hydraulic pump/motor as energy interconvertor, to improve the efficiency of the boom lowering potential energy recovery and engine operation, and the hydraulic hybrid excavator experimental platform was built. The parameter matching difficulty of hydraulic pump/motor and accumulator is effective decreased. The mathmatical model of working hydraulic pump, assistant hydraulic pump/motor, diesel engine and transfer case were built. The hydraulic simulation model of key elements and the dynamic simulation model of excavator working device were built on AMESIM. As well as, the integrated simulation model were built for boom lowering potential energy recovery and engine efficiency optimization.2) The first-order sliding mode variable structure controller for engine speed control of torque coupling hydraulic hybrid excavator is proposed, based on working pump torque load prediction. Simulation and experiments were carried out in this paper. The results show that, based on the proposed method, the engine speed fluctuation is reduced 20%～40%, and the fuel consumption of diesel engine is decreased 4%.3) A potential energy recovery scheme of torque coupling hydraulic hybrid excavator is proposed, based on boom cylinder upper side pressure control within a samll value. As the relative order of pressure control system is two, a second order sliding mode controller for hydraulic pressure control based on super-twisting algorithm is proposed. Simulation and experiments results show that, during the potential energy recovery, the boom cylinder upper side pressure reached the stable level of 22 bar within 2 bar amplitude, and the boom lowering process is stable.