Development of a dual displacement controlled circuit for hydraulic shovel swing motion

• A dual closed hydraulic circuit for swing motion of hydraulic shovel is proposed.
• The proposed swing circuit achieves a smooth acceleration and deceleration.
• Ratio between braking energy and energy consumption in a swing cycle is 23.2%.

Complexity of large structure of hydraulic shovel system drives the guideline development for designing a swing unit of the shovel. Some of the issues are how to achieve smooth swing motion, save energy, and easily adjust its swing velocity. In this paper, we proposed a dual-closed-hydraulic-circuit (DCHC) accordingly to meet the design requirement. In the DCHC system, instead of manual adjustment, the displacement of hydraulic axial piston pump is controlled by programmed software algorithm through electronic control device, which significantly simplifies the current circuit design. The DCHC system also enables controllable recuperation of kinetic energy of swing motion for use by other actuators. Accordingly, the new system will achieve smoother motion compared with existing system and more efficient operation. We demonstrate the advantages of our DCHC design through simulation and verify through developing a hydraulic shovel prototype with bucket capacity of 15 cubic meters and operational weight of 270 tons. Both simulation and experimental results indicate that the DCHC system is feasible and works as intended.