It is an object of the present invention to provide a hydraulic drive system that effectively utilizes a hydraulic fluid accumulated in an accumulator to make it possible to achieve a substantial improvement in terms of efficiency for a work machine as a whole. A hydraulic drive system includes: a first hydraulic pump; a first hydraulic actuator driven by being supplied with a hydraulic fluid from the first hydraulic pump; a first line for supplying the hydraulic fluid from the first hydraulic pump to the first hydraulic actuator; a first pump flow adjustment device installed in the first line, the first pump flow adjustment device being configured to adjust; a first hydraulic accumulator for accumulating the hydraulic fluid delivered from the first hydraulic pump; and a first accumulation flow adjustment device configured to adjust the flow of the hydraulic fluid from the first hydraulic pump to the first hydraulic accumulator. The hydraulic drive system further comprises a first accumulation flow supply device configured to supply the hydraulic fluid accumulated in the first hydraulic accumulator to the first hydraulic actuator via a second line different from the first line.

A control system for controlling a hydraulic installation with a plurality of receivers operating in parallel includes control units which regulate control positions of each of the receivers supplied by a pump, the pressure and flow rate of which are regulated by a regulator with or without flow rate sharing. The distributor associated with each receiver is switched between modes by a switch associated with each receiver. A counter supplies a control signal to the switches in order to switch them to flow rate sharing mode, if at least two receivers must be activated. Each control unit generates a pressure value and a flow rate value in order, in flow rate sharing mode, to generate a flow rate regulation signal corresponding to the sum of all the flow rates, and a pressure signal corresponding to the highest pressure out of all the pressures.

A slewing hydraulic work machine includes a slewing control device performing a slewing control in accordance with an applied slewing command operation, a boom control device performing a boom-raising control in accordance with an applied boom-raising command operation, a boom angle detector, and a capacity control section. The capacity control section calculates a command motor capacity based on a boom angle, generates a capacity command signal corresponding to the command motor capacity and inputs the signal to a slewing motor. During the performance of slewing and boom-raising operation, the capacity control section sets the command motor capacity to a value equal to or less than a base capacity when the boom angle is equal to or less than a slewing priority angle and sets the command motor capacity to a value greater than the base capacity when the boom angle is greater than the slewing priority angle.

An excavator includes a plurality of hydraulic actuators, and a setting unit that performs a setting related to operation speeds of the plurality of hydraulic actuators during a combined operation of the hydraulic actuators, so that when the operation speed of one of the actuators increases, the operation speed of another one of the actuators decreases. The setting unit is capable of performing the setting for a plurality of kinds of combined operations.

A slewing-type work machine includes a slewing state determination section which determines whether or not slewing motion of an upper slewing body is in a deceleration state, and a capacity control section which controls a motor capacity. The capacity control section sets the motor capacity to a capacity set for a combined operation during a performance of the combined operation in which an operation for slewing the upper slewing body and an operation for actuating an attachment are performed simultaneously, while setting the motor capacity to a preset default capacity even during the performance of the combined operation when the slewing state determination section determines that the slewing motion of the upper slewing body is in the deceleration state.

A machine control system can store model weights determined via machine learning using a training dataset correlating preset hydraulic valve displacements to measured movement parameters of a machine component. The machine control system can receive an input command for the component and machine state data from machine sensors. A control mapping model can use the model weights to map a combination of the input command and the machine state data into a predicted displacement of the hydraulic valve that causes movement of the component in response to the input command.

A slewing hydraulic work machine includes a slewing control device performing a slewing control in accordance with an applied slewing command operation, a boom control device performing a boom-raising control in accordance with an applied boom-raising command operation, a boom angle detector, and a capacity control section. The capacity control section calculates a command motor capacity based on a boom angle, generates a capacity command signal corresponding to the command motor capacity and inputs the signal to a slewing motor. During the performance of slewing and boom-raising operation, the capacity control section sets the command motor capacity to a value equal to or less than a base capacity when the boom angle is equal to or less than a slewing priority angle and sets the command motor capacity to a value greater than the base capacity when the boom angle is greater than the slewing priority angle.

A hydraulic system includes a supply line, at least one implement-based control valve, an implement-based pressure regulating valve, and a load sensing circuit. The implement-based control valve(s) is fluidly coupled to the supply line and configured to regulate a flow of the pressurized hydraulic fluid supplied through at least one downstream actuator line to at least one hydraulic actuator of the implement. The implement-based pressure regulating valve is fluidly coupled to the supply line upstream of the control valve(s) and configured to regulate a fluid pressure to be equal to or greater than a minimum fluid pressure. The load sensing circuit is fluidly coupled to the pressure regulating valve and provides a line or load pressure to the pressure regulating valve. The pressure regulating valve is configured to regulate the supply of the pressurized hydraulic fluid based on the line pressure.

A control system and method for controlling the positioning of an adjustable deflector plate employed in a harvesting combine to adjust a side-to-side flow of crop residue to spreaders associated with the combine and the distribution thereby. The deflector plate is operably extendable into the flow of crop residue to redirect crop residue impinging the deflector plate. The deflector plate is adjusted based upon a comparison between the open/closed states of valves associated with the control system.

In a load sensing hydraulic control circuit, a pressure compensator elaborates both a load sensing pressure signal to control a pump unit and a pressure compensated power flow for actuators, the power flow being either split or alternatively directed to at least a first and a second actuator control valves so that a differential pressure across the first and second control valves is controlled by the pressure compensator. In one embodiment, the circuit is onboard a construction vehicle to power actuators such is travel left, travel right, swing, boom, arm, bucket and the like.