Abstract
The modeling for the total system of the hybrid excavator is presented by introducing the flexible multibody system with the electric-hydraulic drive system, which consists of the engine, the battery system, the generator, and actuators driven by the electric-hydraulic power train system. The attachment and the hydraulic system of the hybrid excavator are formulated by introducing the nonlinear finite element analysis. The power electronic system, which includes the battery system, the generator, the convertor, the motor, and the controller, is modeled by employing the analogy of the hydraulic circuits. Firstly, the dynamic simulations are performed by using this model in the boom system for the operability design. It is demonstrated that the vibration control is effective to reduce the residual vibration of the boom. Secondly, the dynamic simulations are carried out for the energy saving performances of the hybrid excavator, which are conducted on the actual operation such as the excavating, and so on. It is verified that the simulation results for both the power and the energy saving performance fairly agree with the experimental ones. The energy saving effects of the hybrid excavator can be expected to be more than 40% for the actual operation comparing with the conventional one.
