An avoidance position specification unit specifies an interference avoidance position that is higher than a loading object and has no loading object therebelow. A timing determination unit determines a swing start timing based on a remaining swing angle formed by a straight line that extends from a center of swing to a work equipment and a straight line that extends from the center of swing to an interference avoidance position, and a height of the interference avoidance position. An operation signal output unit outputs an operation signal of the work equipment in a case of not reaching the swing start timing and outputs an operation signal for swinging a swing body at swing speed higher than that when not reaching the swing start timing and an operation signal of the work equipment, in a case of reaching the swing start timing.

Provided is a work machine with which an operator can easily perform semi-automatic excavating shaping work at an intended excavation velocity. An information processing device calculates a target velocity of a work point at a predetermined position on a work implement on the basis of each of operation signals of operation devices, calculates a distance between the work point and a target surface on the basis of posture information of driven members and position information of the target surface, corrects a velocity component of the target velocity, the velocity component being perpendicular to the target surface, according to the distance such that the work point does not penetrate the target surface, and performs, before calculating the target velocity, weighting on each of the operation signals of the operation devices according to contribution to a velocity component of the work point, the velocity component being parallel to the target surface, on the basis of the posture information of the driven members and the position information of the target surface.

A hydraulic excavator drive system includes a regeneration line, which connects an arm pushing and an arm crowding supply line, each of which extends between an arm cylinder and arm control valve. The regeneration line includes regeneration and switching valves. A release line that is branched off from the regeneration line at a position between the regeneration valve and the switching valve is provided with a release valve. A secondary pressure from a first solenoid proportional valve is fed to a pilot port of the regeneration valve such that the regeneration valve opens at a time of arm crowding. A secondary pressure from a second solenoid proportional valve is fed to a pilot port of the release valve such that release valve opens at a time of arm pushing. An arm pushing pilot pressure for moving the arm control valve is led to a pilot port of the switching valve.

A work machine control device includes a lift force detection unit, a control amount determination unit, and a command output unit. The lift force detection unit detects a lift force of the work machine. The control amount determination unit determines a control amount for the work machine based on a change amount of the detected lift force. The command output unit outputs, to an actuator driving the work machine, a control command according to the determined control amount. The control amount determination unit determines the control amount such that the control amount monotonically increases with respect to the lift force until a lift amount of the work machine reaches a predetermined threshold. A work vehicle includes the work machine control device, a vehicle body, a work machine supported by the vehicle body, and an actuator that drives the work machine.

In a working machine, a stroke of an arm cylinder caused when a distance of a tip portion of an arm from a machine body is equal to a predetermined limit distance is defined as a stroke Y1, a stroke of a boom cylinder caused when the stroke of the arm cylinder is equal to the stroke Y1 and a height of the tip portion of the arm is equal to a height of a boom pivot shaft is defined as a stroke X1, and when the stroke of the boom cylinder is between X1 and a stroke end thereof in a direction to swing the boom upward, the controller restricts the stroke of the arm cylinder to swing the arm in a dumping direction to prevent the arm from swinging further in the dumping direction from a position where the stroke of the arm cylinder is equal to Y1.

A hydraulic drive apparatus includes a boom flow rate control valve, a target boom cylinder speed calculation part calculating a target boom cylinder speed for making a construction surface by a bucket closer to a target construction surface based on the cylinder speed of a boom cylinder and the like, and a boom flow rate operation part. The boom flow rate operation part operates the boom flow rate control valve to make a boom cylinder supply flow rate be a target supply flow rate corresponding to the target boom cylinder speed when the target boom cylinder speed direction coincides with a cylinder thrust direction, and operates the boom flow rate control valve to make the boom cylinder discharge flow rate be a target discharge flow rate corresponding to the target boom cylinder speed when the target boom cylinder speed direction is opposite to the cylinder thrust direction.

A hydraulic work system can include a continuously variable displacement hydraulic pump that is powered by an engine and is in communication with a hydraulic actuator. A run-time displacement of the hydraulic pump for movement of the hydraulic actuator can be controlled based on a speed of the engine.

To provide a construction machine that has a hydraulic system mounted thereon in which a closed-circuit pump, and an open-circuit pump and a proportional valve are arranged as a pair, and that makes it possible to use an unused open-circuit pump or proportional valve to accelerate the speed of a single rod hydraulic cylinder when the single rod hydraulic cylinder and a hydraulic motor are driven simultaneously. A controller (51) controls a cap-side selector valve (46) and a rod-side selector valve (47) such that a particular open-circuit pump (15) not connected to a single rod hydraulic cylinder (3) is connected to the single rod hydraulic cylinder, and controls an opening area of a particular proportional valve (49) provided on a flow line that connects a delivery port of the particular open-circuit pump to a tank, when the single rod hydraulic cylinder and a hydraulic motor (7) are driven simultaneously.

A control system for a construction machine includes a target value generation unit configured to generate a target value of an amount of control of working equipment, a prediction unit configured to calculate a predicted value of the amount of control of the working equipment based on the target value and a prediction model for the working equipment, and calculate an amount of drive to control the working equipment based on the predicted value, and a command unit configured to output a control command for control of the working equipment based on the amount of drive.

A working status indicating a status related to the present work of a hydraulic excavator 1 is determined on the basis of operation signals output from a control lever 24, posture information output from inertial measuring devices 27 to 30, load information output from pressure sensors 32 and 33, and a work area set by a display input device 26, an operation form indicating contents of an operation in operation correction control of a front work implement 12 is decided from a plurality of operation forms set in advance, according to the determined working status, and the operation correction control is performed such that the front work implement moves according to the operation form. Thus, an appropriate assisting operation can be performed in machine control, so that the work accuracy can be improved.