A hydraulic actuator control system includes a secondary manifold that is configured to direct a meter-in flow received from a main directional valve to the actuator and to direct a meter-out flow of fluid received from the actuator directly to a tank without the return flow travelling back through the main directional valve. The hydraulic actuator control system has a separate return flow connection that permits the use of a load-holding valve (such as, e.g., counterbalance valves, motion control valves, pilot-operated check valves, or zero-leakage logic elements) flanged on the machine's actuator (such as, e.g., a linear cylinder, a rotary cylinder, or a hydraulic motor) to create a directional control valve without directing the return flow through the main directional control valve.

A control system includes a cylinder pressure data acquisition unit that acquires cylinder pressure data indicating a pressure of operating oil of a hydraulic cylinder; an operation amount data acquisition unit that acquires operation amount data of an operating device; a pump flow rate calculation unit that calculates a first pump flow rate indicating a flow rate of the operating oil discharged from a first hydraulic pump and a second pump flow rate indicating a flow rate of the operating oil discharged from a second hydraulic pump in a splitting state in which a passage is closed based on the cylinder pressure data and the operation amount data; and a pump control unit that controls the first hydraulic pump and the second hydraulic pump based on the first pump flow rate and the second pump flow rate.

A valve (18), for a valve assembly (10) for regulating the pressure of a fluid guided in a hydraulic system for supplying pressure to at least one hydraulic consumer (12a, 12b), includes a pilot control stage (48) and a main control stage (38) for at least partially clearing or blocking a fluid path from a supply connection (P) to an outflow connection (T). A relief stage (54) for pressure relief of a fluid chamber is arranged between the pilot control stage (48) and the main control stage (38). The relief stage (54) compares the existing load pressure at load terminal (LS) dedicated to the hydraulic consumer (12a, 12b) with the outflow pressure at the outflow connection (T), clearing the pressure relief if both pressures are approximately the same. The relief stage (54) can be directly connected to the load connection (LS) and can be charged with load pressure.

A Control Valve Compensation System for producing both a pre-compensated and a post-compensated load sensing hydraulic directional control valve module, wherein both configurations use the same components except for a sliding compensating component. The Control Valve Compensation System generally includes a hydraulic directional control valve housing which is adapted to be easily-interchangeable between a load sensing pre-compensated pressure configuration and a load sensing post-compensated pressure configuration by simply removing and replacing a different compensator assembly within the housing. The compensator assembly is adapted to direct oil flow through the housing while simultaneously providing compensation for the valve function. Directional valve assemblies may be provided, with the valve assemblies functioning to provide post-compensated functions, pre-compensated functions, and mixed pre- and post-compensated functions. These directional valve functions can be re-configured in the field by simply swapping the compensator assemblies to produce the desired functionality of the end-user at that particular time.