A carrier comprising at least a first hydraulic cylinder and a second hydraulic cylinder both having each a piston and a piston position sensor, wherein the carrier is arranged to carry a tool through the use of the hydraulic cylinders and wherein the controller is configured to: receive control information to move the tool in a direction along a working line; receive position information for the first cylinder; receive position information for the second cylinder; determine if the working line for the tool is maintained, and, if the working line is not maintained, then adapt for the movement of the first cylinder by providing control of the second cylinder to maintain the working line for the tool and thereby feeding the tool along the working line.

The invention relates to a civil engineering device and a civil engineering method for using a civil engineering device. The device has a support device, a ground preparation tool, which prepares the ground at a preparation location, and at least one GPS unit, which is arranged on the support device and is designed to determine the position of the preparation location, wherein the GPS unit is arranged at a distance from the ground preparation location. The civil engineering device is characterised in that a measuring device is provided in addition to the GPS unit, the measuring device being designed to determine the distance between the GPS unit and the preparation tool.

Power machines and control systems used thereon include a lift cylinder, a tilt cylinder, and a slave cylinder mechanically connected to assist the lift cylinder with raising a boom. With a lift control valve controlled to cause extension of the lift cylinder to raise the boom, pressure from a hydraulic source is provided to the slave cylinder to aid in raising the boom. Resulting increased pressure on a side of the slave cylinder opens load holding valves, allowing hydraulic pressure from the tilt cylinder to be communicated to the slave cylinder such that tilt cylinder pressure due to a heavy load on an implement aids in raising the boom.

A construction machine makes it possible for an operator to linearly push a bucket by operating an arm in a pushing direction. A controller is configured to, in case a straight locus is selected by a bucket locus selecting device, calculate a constant flow rate ratio according to a boom initial angle that is an angle of a boom sensed by a boom angle sensor at a time point when an arm is operated in a pushing direction by an operation device, and control the delivery flow rate of a first hydraulic pump such that a hydraulic fluid is discharged from a boom cylinder cap chamber at a flow rate obtained by multiplying a flow rate of a flow supplied to an arm cylinder cap chamber by the flow rate ratio while the arm is operated in the pushing direction and there is no boom operating instruction.

Mobile device includes a frame with displacement means, a working arm connected to the frame including at least a first and a second articulation which are hinged to each other. The working arm is hinged to the frame, and at least a first, second and third control devices are adapted for moving the first and second articulation of the working arm and a tool, respectively, at a free end of the second articulation. A control system is adapted for controlling the first, second and third control means. The control system is adapted to drive the first, second and third control means such that the free end of the second articulation follows a predetermined upward movement along an upwardly directed path and the tool remains in a lifting position, the first, second and third control means are simultaneously controlled.

A work vehicle includes: a hydraulic operation apparatus for operating an actuator; a main controller configured to generate a command current in accordance with an amount of operation of the operation apparatus; an electromagnetic proportional control valve configured to generate command pilot pressure in accordance with the command current; and a main valve configured to adjust a flow rate of hydraulic oil for operating the actuator based on the command pilot pressure. The electromagnetic proportional control valve is provided in a pilot oil passage that connects a pilot pump and a main valve, and configured to utilize hydraulic pressure supplied from the pilot pump to generate command pilot pressure. The operation apparatus is provided in an operation apparatus oil passage that is different from the pilot oil passage.

A valve system, including first, second, third and fourth ports, a first flow path connecting the first and second ports, a second flow path connecting the third and fourth ports, with valves connected in the first and second flow paths, and energizable to block the same. A third flow path connects the first and second ports and a fourth flow path connects the third and fourth ports. The third and fourth flow paths are more restricted than the respective first and second flow paths. A fifth flow path connects the first and fourth ports and a sixth flow path connects the second and third ports. When the third and fourth flow paths are open, the first, second, fifth, and sixth flow paths are blocked. When the first and second flow paths are open, the third, fourth, fifth, and sixth flow paths are blocked. When the fifth and sixth flow paths are open, the first, second, third, and fourth, flow paths are blocked.

A construction machine is capable of preventing degradation in efficiency of excavation work while preventing an increase in excavation resistance in the excavation work. A controller of a construction machine determines an accommodation state of earth and sand accommodated in a bucket, and outputs a resistance reduction command signal that is a command signal for operating a work device such that the bucket is displaced in a resistance reduction direction that is a direction where excavation resistance acting on the bucket is capable of being reduced, in accordance with a result of determining the accommodation state.

Provided is a hydraulic excavator including a controller that can control a work device by utilizing an excavation work control for causing a claw tip of a bucket to move along a predetermined target surface and a leveling work control for causing the bucket to move along the target surface while maintaining the posture of the bucket with respect to the target surface, in which: the controller, based on posture data and size data on a work device and position data on the target surface, calculates an arm tip difference Dva that is the distance from the tip of an arm to the target surface; and the controller executes the leveling work control in a case of the calculated arm tip difference being equal to or less than a predetermined threshold dv1, there being no input of a bucket operation to an operation lever, and there being an input of an arm operation to the operation lever, and otherwise executes the excavation work control.

A method of controlling a lift arm actuator and a tilt actuator to control positioning of an implement carrier coupled to a lift arm of a power machine. An activation signal is received from an enabling input device. A lift arm control signal is received from a lift arm control input commanding movement of the lift arm. The lift arm actuator is controlled responsive to receipt of both of the activation signal and the lift arm control signal to move the lift arm to a target lift arm position and to move the implement carrier to or maintain the implement carrier at a target implement carrier orientation relative to a gravitational direction.