A hydraulic system for a construction machine having a pressure compensation valve is disclosed, which improves operability when a combined operation of a swing device and an attachment is performed. The hydraulic system includes a hydraulic pump, attachment and swing operation devices, an attachment actuator and a swing motor connected to the hydraulic pump, a first control valve controlling hydraulic fluid being supplied to the actuator, a second control valve controlling hydraulic fluid being supplied to the swing motor, a check valve installed on a flow path for detecting load pressures of the actuator to take a maximum pressure of the load pressures, a first pressure compensation valve having an opening amount that is controlled by a difference between the maximum load sensing pressure and the pressure of a discharge flow path of the first control valve, a second pressure compensation valve having an opening amount that is controlled by a difference between the maximum load sensing pressure and the pressure of the discharge flow path of the second control valve, a maximum load pressure sensor detecting the pressure of a maximum load sensing pressure line, and a control unit controlling a discharge flow rate of the hydraulic pump, wherein the system is configured so that the swing load pressure is not connected to the first pressure compensation valve on the attachment side when a combined operation of the swing device and the attachment is performed.

An arrangement for operating a hydraulic consumer including a hydraulic control valve having a main slide valve defining a hydraulic volume flow in the direction of hydraulic connections provided for operation of the hydraulic consumer, a pressure compensation valve and an orifice, the pressure compensation valve controlled on the basis of a pressure difference that drops at the orifice when the volume flow passes through, such that the pressure compensation valve adopts an at least partially closing control position when the hydraulic pressure upstream of the orifice in the direction of the volume flow is greater than downstream of the orifice, including a restoring spring force of a spring element preloading the pressure compensation valve into a fully open position, and a sensor arrangement sensing the pressure difference and transmitting a pressure difference value derived therefrom to a control unit evaluating the pressure difference value.

The present disclosure relates to variable recruitment actuator systems and related methods. In one embodiment, a variable recruitment actuator system utilizes a central hydraulic pump, an accumulator, a plurality of variable recruitment actuators, and a pressurized reservoir of hydraulic fluid to provide highly efficient hydraulic regenerative energy harvesting in systems requiring both eccentric and concentric motion. In another embodiment, a powered prosthetic or orthotic device, or a legged robot, utilizes a system as previously described to capture energy from the eccentric motion of the knee joint to provide concentric motion of both the knee and ankle joints later on in a gait cycle.