Energy and Control Characteristics of a Novel Meter Out Hydraulic System for Mobile Applications

The metering out sensing system represents the latest, and most promising, architectural concept for improving the performance of mobile multiple actuation systems through hydraulic proportional components control. The first part of the paper introduces the novel architecture of meter-out sensing control system, properly designed to distribute the flow rate directed to actuators according to the proportional control of the metering out element only. To do this, an innovative piloting subsystem controls the pump displacement, while a set of compensated proportional control valves applied to actuators outlet work to manage the load unbalance. The inlet doesn't have any proportional throttle element thus reducing control losses with respect to state-ofthe-art systems. In this way, the architecture is able to control both resisting and overrunning loads, and its design could easily include the automatic activation of the regenerative function to limit the requested hydraulic power. Then, the paper highlights how the proposed architecture of meter-out sensing system, which does not require complex sensor networks or complex electronic controls, could overcome the most important limitations affecting other control technologies currently adopted in mobile hydraulics. The third part of the paper depicts the main results obtained in the evaluation of the performance figures of merit for the metering out sensing system, performed through a Virtual Test Procedure applied to a lumped and distributed parameter numerical model.