A hydraulic excavator 1 includes an engine 16, a main hydraulic pump 17 driven by the engine 16, a plurality of hydraulic actuators driven with pressure oil discharged from the main hydraulic pump 17, a plurality of flow rate control valves adapted to control the flow rate of pressure oil to be supplied from the main hydraulic pump 17 to the respective hydraulic actuators, a pilot hydraulic pump 18 adapted to supply pressure oil for driving the flow rate control valves, and a controller 15 configured to control the discharge flow rate of the pilot hydraulic pump 18. The controller 15 controls the discharge flow rate of the pilot hydraulic pump 18 such that it becomes equal to the sum of requested pilot flow rates determined in accordance with control commands for the respective flow rate control valves and a preset standby flow rate.

A robotic device may traverse a path in a direction of locomotion. Sensor data indicative of one or more physical features of the environment in the direction of locomotion may be received. The implementation may further involve determining that traversing the path involves traversing the one or more physical features of the environment. Based on the sensor data indicative of the one or more physical features of the environment in the direction of locomotion, a hydraulic pressure to supply to the one or more hydraulic actuators to traverse the one or more physical features of the environment may be predicted. Before traversing the one or more physical features of the environment, the hydraulic drive system may adjust pressure of supplied hydraulic fluid from the first pressure to the predicted hydraulic pressure.

A fluid power system comprises a pump with multiple independently variable outlets, each of which is capable of delivering fluid in individually controllable volume units and a plurality of hydraulic loads. A system of switching valves is configured to create fluid connections between the pump outlets and the loads. A control system commands both the pump and the switching valves, so as to create valve state combinations to satisfy load conditions as demanded by an operator. The number of pump outlets connected to one or more of the loads is changeable to satisfy the flow required of the load due to the operator demand, each pump outlet being commanded to produce a flow depending on the status of other outlets connected a load to which the outlet is connected and the operator demand for that load.

A portable hydraulic power unit includes a frame, a fluid tank supported by the frame, and a manifold supported by the frame. The fluid tank is configured to store a supply of hydraulic fluid for powering a hydraulically-driven tool. A reciprocating pump is mounted on the exterior of the fluid tank and on the exterior of the manifold. The reciprocating pump is secured to the fluid tank and the manifold with fasteners extending through a cylinder body of the reciprocating pump.

A portable hydraulic power unit includes a frame, a fluid tank supported by the frame, and a manifold supported by the frame. The fluid tank is configured to store a supply of hydraulic fluid for powering a hydraulically-driven tool. A reciprocating pump is mounted on the exterior of the fluid tank and on the exterior of the manifold. The reciprocating pump is secured to the fluid tank and the manifold with fasteners extending through a cylinder body of the reciprocating pump.

A hydraulic power system for a downhole device, including a first motor, a first hydraulic pump, a second hydraulic pump, a first main oil circuit, a second main oil circuit, a switching control module and a first execution module. The first motor has a first output shaft which drives the first hydraulic pump and has an oil outlet connected to an input end of the first main oil circuit and a second output shaft which drives the second hydraulic pump and has an oil outlet connected to an input end of the second main oil circuit; the first execution module is connected to an output end of the first main oil circuit; displacement of the first hydraulic pump is smaller than that of the second hydraulic pump; and the switching control module is connected between the first main oil circuit and the second main oil circuit.

A double-power-supply complex control device includes a main body. Four control sections and two load flow ways are disposed in the main body. A main flow way is disposed in control section. Four switch members of a switch assembly are assembled and disposed in the main flow ways. A circumference of each main flow way is in communication with multiple bypasses. The main flow ways of each two of the control sections are in communication with a fluid output passage and a fluid input passage of a power device. Some of the bypasses of control section are in communication with each other. A lower flow guide window is disposed on switch member in indirect communication with main flow way. When switch member is operated under external force, the lower flow guide window is switchable between the bypasses to selectively communicate with the bypasses to make different power devices drive.

An excavator with a boom comprises a main electrical drive system with an electrical power storage unit. The excavator comprises an electrical drive configured to actuate movement of the boom to raise and/or lower part of the boom. The excavator comprises a separate fluid-operated, auxiliary actuation system for storing potential energy of the part of the boom during lowering thereof and for using the stored potential energy to support raising of the part of the boom. The auxiliary actuation system is configured to store the potential energy and to support raising the part of the boom autonomously without interaction with the main electrical drive system.

A distributed electrohydraulic system includes an electrical power source, electrohydraulic modules, and a control system. Each of the electrohydraulic modules includes one or more hydraulic components and one or more electrically-operated components which affect an operation of the one or more hydraulic components. The one or more hydraulic components of each of the electrohydraulic modules is hydraulically isolated from the one or more hydraulic components of another one of the electrohydraulic modules The one or more electrically-operated components of each of the electrohydraulic modules is electrically coupled to the electrical power source to receive electrical power. The control system includes one or more processors and memory devices electrically coupled to the electrical power source and the one or more electrically-operated components of the electrohydraulic modules. The control system is configured to execute commands to operate independently the one or more electrically-operated components of each of the electrohydraulic modules.

A robotic device may traverse a path in a direction of locomotion. Sensor data indicative of one or more physical features of the environment in the direction of locomotion may be received. The implementation may further involve determining that traversing the path involves traversing the one or more physical features of the environment. Based on the sensor data indicative of the one or more physical features of the environment in the direction of locomotion, a hydraulic pressure to supply to the one or more hydraulic actuators to traverse the one or more physical features of the environment may be predicted. Before traversing the one or more physical features of the environment, the hydraulic drive system may adjust pressure of supplied hydraulic fluid from the first pressure to the predicted hydraulic pressure.