A construction machine that can make a depressing force of a bucket during compaction work to be uniform without requiring an operator to perform a complicated operation is provided. A controller 18 determines whether or not compaction work is in progress, calculates a front distance R that represents a distance between a rotational pivot of a boom 4 and a predetermined position B in a back surface of a bucket 6, determines a target velocity of the bucket such that a velocity with which the bucket approaches a leveling target surface decreases with increasing values of the front distance, and, during the compaction work, notifies the operator of details of an operation of operation devices 9a and 9b for achieving the target velocity of the bucket or controls hydraulic actuators 4a to 6a so as to achieve the target velocity of the bucket.

Provided is hybrid construction machine that can charge/discharge an electrical storage device appropriately and can suppress stop of an engine accompanying sharp increase of a load. The present invention includes a hybrid controller 22 that controls power of a hydraulic pump 17 and electric power of an inverter 15 in response to storage battery characteristics of the electrical storage device 16, and an output command unit 22F of the hybrid controller 22 is configured to control at least either one of the power of the hydraulic pump 17 and the electric power of the inverter 15 on the basis of at least either one of electric current or voltage of the storage battery characteristics and at least either one of temperature or a state of charge of the storage battery characteristics.

A construction machine includes a hydraulic cylinder configured to drive an attachment, a hydraulic circuit configured to supply hydraulic oil to the hydraulic cylinder, an input device that is operated by an operator, and a controller configured to control the hydraulic circuit in at least one of a first control mode where the attachment is caused to generate a force corresponding to an operation amount of the input device and a second control mode where the attachment is driven at a velocity corresponding to the operation amount of the input device.

A hydraulic control apparatus is disclosed that controls a hydraulic pump in a construction machine in which a hydraulic actuator is connected to the hydraulic pump via a directional control valve of a closed center type, and in which a position of the directional control valve is changed according to an operation amount of an operation member. The hydraulic control apparatus includes a virtual negative control pressure calculating part configured to calculate, based on the operation amount of the operation member and a discharge pressure of the hydraulic pump, a virtual negative control pressure when a negative control system is assumed; and a part configured to calculate a control command value for the hydraulic pump based on the virtual negative control pressure.

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 calibration system includes at least a pair of imaging devices in a work machine having a working unit that image an object; a position detector detecting a position of the working unit; and a processing unit that, by using first position information about a predetermined position of the working unit captured by the imaging devices, second position information about the predetermined position detected by the position detector in an attitude of the working unit taken when the imaging devices image the predetermined position, and third position information about a predetermined position outside the work machine, imaged by the imaging devices, obtains information about a position and an attitude of the imaging devices, and transformation information used for transforming a position of the object imaged by the imaging devices from a first coordinate system to a second coordinate system.

A drive control system for a work machine includes: a stabilization control calculation unit (60a) that calculates and outputs a gradual stoppage command and an operation speed limitation command; a stoppage characteristic modification unit (210) that includes a speed increasing unit and corrects a pilot pressure such that, upon a stoppage operation of a control lever, a drive actuator is stopped gradually; an operation speed limitation unit (240) that includes a speed reducing unit and corrects the pilot pressure such that an operation speed of the drive actuator is limited; and a speed increase interruption unit (330) that interrupts, when a failure of a speed increasing solenoid proportional valve of the speed increasing unit is detected, supply of the pilot hydraulic fluid to the speed increasing unit.

To provide a work machine that enables enhancement of shaping accuracy near a boundary line between two adjacent target surfaces. A controller 10 extracts, from among a plurality of target surfaces, a second target surface S2 that is a target surface adjacent to a first target surface S1, calculates a boundary line L2 between the first target surface S1 and the second target surface S2, and, prior to a work tool 6 passing the first boundary line L2, corrects a control signal for a posture control actuator 6c such that the angular difference E.sub.L between a reference line L1 set on the work tool 6 and the boundary line L2 becomes small.

A hydraulic system (40) for a work machine comprising a priority circuit (41) including at least a first priority actuator (47, 48) and a priority control valve (58) for controlling the supply of hydraulic fluid to the first priority actuator (47, 48) and for providing a load sense signal indicative of the load acting on the first priority actuator (47, 48); an auxiliary circuit (42) including at least a first auxiliary actuator (51) and at least a first auxiliary control valve (80) for controlling the supply of hydraulic fluid to the first auxiliary actuator (51); at least a first pump (46) for producing a flow of hydraulic fluid; and a priority valve (74) for distributing the flow from the pump (46) to the priority circuit (41) and auxiliary circuit (42) for operating the respective actuators thereof, with priority being given to the priority circuit (41) as a function of the load sense signal.

According to the present invention, a hydraulic system of construction equipment is implemented as a close center system, which converts an input signal of an electric or hydraulic joystick into a speed signal of a work apparatus, and controls a speed of the work apparatus regardless of an external load condition, thereby minimizing fatigue of a worker to improve work efficiency, improving a work apparatus operation ability of an unskilled person, and patterning standardized work to implement automation of construction equipment.