Abstract: Pump-controlled hydraulic circuits are more efficient than valve-controlled circuits, as they eliminate the energy losses due to flow throttling in valves and require less cooling effort. Presently existing pump-controlled solutions for single rod cylinders encounter an undesirable performance during certain operating conditions. Novel circuit designs employ use of different charge pressures on a pair of pilot-operated charging-control valves or different piston areas and/or spring constants on a shuttle-type charging control valve to shift a critical loading region in a load-force/actuator-velocity plane to a lower load force range, thereby reducing the undesired oscillations experienced in the response of the typical critical loading region.

Abstract: Pump-controlled hydraulic circuits are more efficient than valve-controlled circuits, as they eliminate the energy losses due to flow throttling in valves and require less cooling effort. Presently existing pump-controlled solutions for single rod cylinders encounter an undesirable performance during certain operating conditions. Novel circuit designs employ use of different charge pressures on a pair of pilot-operated charging-control valves or different piston areas and/or spring constants on a shuttle-type charging control valve to shift a critical loading region in a load-force/actuator-velocity plane to a lower load force range, thereby reducing the undesired oscillations experienced in the response of the typical critical loading region.