Abstract:

Conventional swing system of hydraulic excavator is controlled by a valve control system with single degree of freedom due to the fact that its inlet and outlet orifices are connected mechanically, as a consequence, it has some disadvantages such as bad controllability and high energy consumption. To solve this problem, a separate meter-in and meter-out hydraulic excavator swing system with pump and valve combined control and flow rate matching is proposed. In this system, the pressure and flow rate of the motor working chambers can be controlled independently according to the working condition. Furthermore, a virtual prototype is developed consisting of the hydraulic excavator mechanical structure with multi-body dynamics and electro-hydraulic system for analyzing the feasibility of this swing system, and the simulation result demonstrates that this system works smoothly. After using the presented control strategies, compared with the LUDV system, the result of the experiment shows that a reduced energy consumption of up to 25.5%-35.6% for the swing drive is achieved, the system can reduce the throttle loss 50% and suppress the swing vibration obviously.

Key words: energy efficiency, flow rate matching, pump and valve combined control, separate meter-in and meter-out, swing system