Abstract: Provided is a remote control system for work machine capable of enhancing the stability and efficiently improving the operability. A remote control system for a work machine having a plurality of actuators 31 corrects all command signals for the actuators 31 being operated when a communication delay time occurs during operation with the actuators 31. This limits the operation of the actuators 31 while keeping the ratio of the command signals (operation signals) of the actuators 31.

Abstract: There is provided a construction machine that achieves both safety and operability by lowering the possibility of an accident due to contact between the construction machine and a worker in the periphery of a vehicle body while securing operability in situations where an object required for work is present in the periphery. A controller has a normal mode as a control mode for making the operation limiting control effective and a temporary cancelation mode as a control mode for temporarily canceling the operation limiting control. The controller shifts to the temporary cancelation mode in response to operation of the control canceling device while in the normal mode. The controller shifts back to the normal mode in a case where a predetermined condition not responsive to operation of the control canceling device is satisfied while in the temporary cancelation mode.

Abstract: In a hydraulic excavator including a main controller that can execute area restriction control, the main controller is configured to calculate an operation velocity Vfx of a front work device in a machine body coordinate system and a movement velocity (dragging velocity) Vu of a machine body in a gravity coordinate system and correct a direction of a calculated target velocity vector Vt upward away from a construction target surface when generation of dragging is detected during execution of the area restriction control based on the calculated operation velocity Vfx of the front work device 2 and the calculated movement velocity Vu of the machine body.

Abstract: When an operation amount of an operation lever corresponding to a boom cylinder is equal to or smaller than an operation amount of an operation lever corresponding to an arm cylinder, an estimated velocity of the arm cylinder used for region limiting control is computed on the basis of a first condition defining, in advance, a relation between the operation amount of the operation lever and the estimated velocity of the arm cylinder. When the operation amount of the operation lever corresponding to the boom cylinder is larger than the operation amount of the operation lever corresponding to the arm cylinder, the estimated velocity of the arm cylinder used for the region limiting control is computed as a velocity higher than the estimated velocity of the arm cylinder computed on the basis of the first condition. The behavior of the work device can thereby be stabilized.

Abstract: A hydraulic actuator includes a control valve unit that controls a flow of a hydraulic fluid supplied from a hydraulic pump to a plurality of hydraulic actuators, a plurality of control lever devices that output a pilot pressure actuating the control valve unit, with use of a discharged pressure from a pilot pump as a source pressure, a solenoid valve unit including a plurality of solenoid pressure reducing valves connected between the plurality of control lever devices and the control valve unit, and a controller configured to calculate velocity limits for the plurality of hydraulic actuators on the basis of signals from a plurality of posture sensors and control openings of the solenoid pressure reducing valves, in which the controller is configured to control the openings of the solenoid pressure reducing valves for arm crowding and arm dumping to be larger than an opening based on the velocity limits while a boom raising operation signal is being output from the control lever devices.

Abstract: A main controller generates a supplemented design face that passes through a junction or above the junction between a first design face and a second design face adjacent to each other, among a plurality of design faces, the supplemented design face having one end thereof positioned on the first design face and another end thereof positioned on the second design face, sets a curvature 1/R of the supplemented design face according to an arm operation amount of an operation lever device, and executes semi-automatic excavation control to control a boom cylinder with one of the faces included in the supplemented design face being set as the target face.

Abstract: A work machine includes a work device having a boom, an arm, and work equipment and a controller that sets a target surface, and calculates a work equipment-to-target surface distance on the basis of signals from a position sensor and a posture sensor, and controls the boom and carries out deceleration control to decelerate the arm to keep the work equipment from excavating ground beyond the target surface when operation of the arm is carried out and the work equipment-target surface distance has become shorter than a predetermined distance.

Abstract: In a specific state where the raising operation of a boom 25 and the swing operation of an upperstructure 21 are performed at the same time to supply a hydraulic oil from a first pump 2 to a cylinder 7a through a first valve 6a, and to supply the same from a second pump 3 to a motor 7b through a second valve 6b, a controller 10 outputs the command current for opening a valve 13, and supplies a part of the hydraulic oil supplied to the motor 7b from the second pump 3 to the cylinder 7a through the third valve 6c when the motor 7b does not reach a steady swing state, and outputs a command current for closing the valve 13 when the motor 7b is in the steady swing state.

Abstract: When a bucket 10 is grounded on soil, an operation signal is outputted or corrected such that a relative angle of the bucket 10 with respect to a target surface is maintained if a distance D between the bucket 10 and the target surface 60 is equal to or less than a preset first threshold value D1. When the bucket 10 is not grounded on soil, the operation signal is outputted or corrected such that the relative angle of the bucket 10 with respect to the target surface 60 is maintained if the distance between the bucket 10 and the target surface 60 is equal to or less than a preset second threshold value D2 set smaller than the first threshold value D1. As a result, control to maintain an angle of a work tool can be suitably started.

Abstract: In a specific state where the raising operation of a boom 25 and the swing operation of an upperstructure 21 are performed at the same time to supply a hydraulic oil from a first pump 2 to a cylinder 7a through a first valve 6a, and to supply the same from a second pump 3 to a motor 7b through a second valve 6b, a controller 10 outputs the command current for opening a valve 13, and supplies a part of the hydraulic oil supplied to the motor 7b from the second pump 3 to the cylinder 7a through the third valve 6c when the motor 7b does not reach a steady swing state, and outputs a command current for closing the valve 13 when the motor 7b is in the steady swing state.

Abstract: A controller for a hydraulic excavator includes a first speed computation section that calculates a first speed of an arm cylinder from a value detected by an operation amount sensor; a second speed computation section that calculates a second speed from a value detected by a posture sensor and a third speed computation section calculates a third speed that is used as the speed of the arm cylinder in an actuator control section adapted to execute MC (machine control). The third speed computation section calculates the first speed as the third speed during the period between the detection of an input of operation for an arm by the operation amount sensor and predetermined time to, the third speed as a speed calculated from the first speed and the second speed during the period between t0 and time t1, and the second speed as the third speed at and after time t1.

Abstract: In a construction machine with a hydraulic pilot type hydraulic control device, occurrence of jerking is prevented. A hydraulic excavator 1 having hydraulic pumps 51L and 51R, travel motors 22L and 22R, traveling operating levers 34L and 34R, a pilot pump 54, hydraulic pilot valves 55La, 55Lb, 55Ra, and 55Rb, and directional control valves 53L and 53R includes: changeover switches 35L and 35R which change the operating mode of the traveling operating levers 34L and 34R; pilot pressure adjusting devices 5L and 5R which adjust the pilot pressure applied to the directional control valves 53L and 53R; and pilot pressure sensors 56La, 56Lb, 56Ra, and 56Rb. The pilot pressure adjusting devices apply the pilot pressure at the time when the operating mode of the traveling operating levers 34L and 34R is changed to a control mode, to the directional control valves 53L and 53R.

Abstract: To prevent increase/decrease in pump flow rate due to load variation with change in the posture of a work attachment and improve the operability in arm pushing operation.

Abstract: A controller for a hydraulic excavator includes a first speed computation section that calculates a first speed of an arm cylinder from a value detected by an operation amount sensor; a second speed computation section that calculates a second speed from a value detected by a posture sensor and a third speed computation section calculates a third speed that is used as the speed of the arm cylinder in an actuator control section adapted to execute MC. The third speed computation section calculates the first speed as the third speed during the period between the detection of an input of operation for an arm by the operation amount sensor and predetermined time to, the third speed as a speed calculated from the first speed and the second speed during the period between t0 and time t1, and the second speed as the third speed at and after time t1.

Abstract: In a construction machine with a hydraulic pilot type hydraulic control device, occurrence of jerking is prevented. A hydraulic excavator 1 having hydraulic pumps 51L and 51R, travel motors 22L and 22R, traveling operating levers 34L and 34R, a pilot pump 54, hydraulic pilot valves 55La, 55Lb, 55Ra, and 55Rb, and directional control valves 53L and 53R includes: changeover switches 35L and 35R which change the operating mode of the traveling operating levers 34L and 34R; pilot pressure adjusting devices 5L and 5R which adjust the pilot pressure applied to the directional control valves 53L and 53R; and pilot pressure sensors 56La, 56Lb, 56Ra, and 56Rb. The pilot pressure adjusting devices apply the pilot pressure at the time when the operating mode of the traveling operating levers 34L and 34R is changed to a control mode, to the directional control valves 53L and 53R.

Abstract: To prevent increase/decrease in pump flow rate due to load variation with change in the posture of a work attachment and improve the operability in arm pushing operation.

Abstract: To provide an engine lug-down suppressing device for hydraulic work machinery, capable of suppressing deterioration in operability of a hydraulic actuator when the hydraulic actuator is caused to operate quickly from a stopped state. Pilot pressure to a tilting control unit of a variable displacement hydraulic pump is controlled by a solenoid valve. A controller controls the solenoid valve in accordance with a target rotational speed signal from an input unit. This control differs according to whether or not a detector detects the pilot pressure created by an operating lever device. In an entire range of the target engine rotational speed, pump absorption torque at the time when the pilot pressure is not detected, falls within a range equal to or smaller than pump absorption torque at the time when the pilot pressure is detected, and is set to approach the pump absorption torque at the time when the pilot pressure is detected with an increase in the target engine rotational speed.

Abstract: A target speed setting section sets a target speed of an engine to an idle speed that is lower than an input speed with an engine control dial when no operating signal is output from a control lever over a predetermined period of time. A speed control section controls the speed of the engine based on the target speed set by the target speed setting section, which includes an idle speed setting section that corrects the idle speed according to values detected by sensors so that reduction in an output of the engine due to a change in a state quantity associated with an environment under which the engine is placed can be inhibited. This allows a good operating condition to be achieved during a reset from an auto idle state even with an engine output has been reduced according to a change in environment.

Abstract: A target speed setting section sets a target speed of an engine to an idle speed that is lower than an input speed with an engine control dial when no operating signal is output from a control lever over a predetermined period of time. A speed control section controls the speed of the engine based on the target speed set by the target speed setting section, which includes an idle speed setting section that corrects the idle speed according to values detected by sensors so that reduction in an output of the engine due to a change in a state quantity associated with an environment under which the engine is placed can be inhibited. This allows a good operating condition to be achieved during a reset from an auto idle state even with an engine output has been reduced according to a change in environment.

Abstract: Torque control for a construction machine three-pump system that can accurately control the total absorption torque of first, second, and third hydraulic pumps and effectively use the output torque of an engine. A pump base torque computation section 42 calculates a pump base torque Tr from a target rotation speed. A subtraction section 44 calculates a reference value Tf for the maximum absorption torque available to the first and second hydraulic pumps 2, 3 by subtracting a third pump reference absorption torque T3r from the pump base torque Tr. A correction torque computation section 45 calculates a correction torque value from the delivery pressure of the third hydraulic pump 4. An addition section 46 calculates a target absorption torque Tn by adding the correction torque value Tm to the reference value Tf. A first regulator 31 is controlled so as to obtain the target absorption torque Tn.