CN-122029328-A - Engineering machinery

CN122029328ACN 122029328 ACN122029328 ACN 122029328ACN-122029328-A

Abstract

The construction machine is provided with a flow control valve as a hydraulic device for adjusting the flow rate supplied to a hydraulic cylinder for driving a work implement, and a control device for controlling the hydraulic cylinder so as to satisfy the condition that the work implement is moved without exceeding a target surface. The control device calculates a target speed of the hydraulic cylinder that causes the work tool to satisfy the condition based on the detection information of the detection device that detects the posture of the work device and the information of the target surface, and if the target value of the hydraulic machine corresponding to the calculated target speed is smaller than a lower limit value that ensures the accuracy of the flow control, then calculates the target speed of the hydraulic cylinder that causes the work tool to satisfy the condition based on the limit speed of the hydraulic cylinder obtained from the lower limit value, and controls the hydraulic machine based on the target value corresponding to the calculated target speed.

Inventors

Bear Valley sage
Jin Binchongyan
FUKUCHI RYOHEI
Yuki Yusuke
AMANO HIROAKI
Bai Tuzhong
Yi Zeqing

Assignees

日立建机株式会社

Dates

Publication Date: 20260512
Application Date: 20240927
Priority Date: 20230929

Claims (5)

1. A construction machine is provided with: a work device including a work tool; at least one hydraulic actuator that drives the work device; a hydraulic device capable of adjusting a flow rate of hydraulic oil supplied to the hydraulic actuator; A control device that controls the hydraulic actuator via the hydraulic device so as to satisfy a condition that the work tool does not exceed a target surface set as a work object to move; a posture detecting device that detects a posture of the working device, It is characterized in that the method comprises the steps of, The control device calculates a target value of the hydraulic device corresponding to the calculated target speed of the hydraulic actuator, based on the detection information of the posture detection device and the setting information of the target surface, calculates a speed of the hydraulic actuator, which satisfies the condition, as a target speed, calculates a speed of the hydraulic actuator, which is obtained from the lower limit value, as a limiting speed of the hydraulic actuator, when the calculated target value of the hydraulic device is smaller than a lower limit value, which can ensure the allowable accuracy of the hydraulic device for flow control, and re-calculates the target speed of the hydraulic actuator, which satisfies the condition, based on the calculated limiting speed of the hydraulic actuator, and controls the hydraulic device, based on the calculated target speed of the hydraulic actuator, with the target value of the hydraulic device as a control target, corresponding to the re-calculated target speed of the hydraulic actuator.
2. The construction machine according to claim 1, wherein the working machine is, The at least one hydraulic actuator driving the work device is constituted by a plurality of hydraulic actuators, The calculation of the target speed of the hydraulic actuator in the control device calculates the target speed of each of the plurality of hydraulic actuators based on the movement direction of the work tool obtained from the instruction information that instructs the operation of the work device, in addition to the detection information of the posture detection device and the setting information of the target surface, The re-calculation of the target speed of the hydraulic actuator in the control device calculates the speeds of the plurality of hydraulic actuators that maintain the movement direction of the work tool and satisfy the condition based on the calculated limit speed.
3. The construction machine according to claim 1, wherein the working machine is, The hydraulic device is a flow control valve capable of controlling the flow rate of hydraulic oil supplied to the hydraulic actuator, The construction machine further includes a pressure detection device that detects a differential pressure between the front and rear sides of the flow control valve, The target value of the hydraulic device is a target opening area of the flow control valve calculated based on a target flow rate of the hydraulic actuator obtained from the calculated target speed of the hydraulic actuator and a detection value of the pressure detection means, The lower limit value is a limit opening area preset for the flow control valve according to the accuracy of flow control of the flow control valve, The calculation of the limiting speed of the hydraulic actuator in the control device is performed based on the flow rate calculated using the limit opening area of the flow rate control valve and the detection value of the pressure detection device.
4. A construction machine according to claim 3, wherein, The construction machine further includes a direction control valve that controls a flow direction of the hydraulic oil supplied to the hydraulic actuator and is capable of controlling a flow of the hydraulic oil discharged from the hydraulic actuator, The flow control valve is disposed on an upstream side of the directional control valve, The pressure detection device includes a pressure sensor that detects a meter-in pressure and a meter-out pressure of the hydraulic actuator, The control device controls the meter-out opening of the directional control valve based on thrust information or pressure information of the hydraulic actuator obtained from a detection value of the pressure sensor.
5. The construction machine according to claim 1, wherein the working machine is, The hydraulic device is a hydraulic pump that supplies hydraulic oil to the hydraulic actuator, The target value of the hydraulic device is a target flow rate of the hydraulic pump calculated based on a target flow rate of the hydraulic actuator obtained from the calculated target speed of the hydraulic actuator, The lower limit value is a limit flow rate preset for the hydraulic pump according to the accuracy of flow rate control of the hydraulic pump, The operation of the limiting speed of the hydraulic actuator in the control device is performed based on the limit flow rate of the hydraulic pump.

Description

Engineering machinery Technical Field The present invention relates to a construction machine, and more particularly, to a construction machine in which a work implement driven by a hydraulic actuator is controlled to operate under predetermined conditions. Background A construction machine such as a hydraulic excavator includes a vehicle body including a swing body and a work implement attached to the swing body. The driven body such as the swing body and the working device is driven by a hydraulic actuator such as a hydraulic motor and a hydraulic cylinder. The working device is an articulated device configured by rotatably connecting a plurality of link members, and is configured by, for example, a boom rotatably connected in the up-down direction with respect to a rotating body, an arm rotatably connected in the up-down direction to the tip end of the boom, and a bucket rotatably connected in the up-down direction to the tip end of the arm. The boom, the arm, and the bucket are driven by a boom cylinder, an arm cylinder, and a bucket cylinder, respectively. It is not easy to excavate a predetermined area by operating a plurality of link members constituting the working device by manual operation of the operating device, and an operating technique familiar to an operator is required. Accordingly, as an example of measures for facilitating such an operation, a technique described in patent document 1 is known. The area limiting excavation control device for a construction machine disclosed in patent document 1 performs control for decelerating movement of a front device (work implement) in a direction approaching a boundary of a set area by correcting an operation signal of an operation lever device related to the front device by a first signal correction means. When the front device approaches the boundary of the setting area, the movement in the approaching direction of the boundary is decelerated, and therefore the front device can be moved along the boundary of the setting area. Thus, the operator can perform stable work with high accuracy without being affected by the skill of the operation technique. However, the technique described in patent document 1 has the following problems. In the case of performing semiautomatic control of the front device (working device) in accordance with an instruction of the control device that corrects the operation signal of the lever device, it is important that the front end of the front device accurately moves along the target trajectory. For this reason, it is necessary to match the flow rate of the hydraulic oil supplied to the hydraulic actuator that drives the front device with the target flow rate. In the area restriction excavation control apparatus described in patent document 1, the opening amount of the flow control valve is adjusted by controlling the control pressure (pilot pressure) of the drive flow control valve, thereby controlling the supply flow rate to the hydraulic actuator. However, even if the opening amount of the flow control valve can be accurately controlled, if the differential pressure across the flow control valve varies with load variation of the front device (variation in load pressure of the hydraulic actuator), the flow rate of the hydraulic oil supplied to the hydraulic actuator via the flow control valve may vary and become unstable. As a means for solving such problems, for example, a technique described in patent document 2 has been proposed. In the hydraulic static drive system described in patent document 2, the flow rate of the pressure medium (hydraulic oil) supplied to the consumer (hydraulic actuator) is controlled by an adjustment valve (flow control valve) having a throttle function. The opening amount of the regulator valve is adjusted based on the pressure drop (front-rear differential pressure) of the regulator valve detected by the pressure sensor so as to supply the volume flow rate requested by the setting device to the consumer. Thus, even if the load pressure of the consumer and the supply pressure of the hydraulic pump vary, the flow rate of the pressure medium supplied to the consumer can be accurately controlled without an additional pressure compensator. Prior art literature Patent literature Patent document 1 International publication No. 1995/030059 Patent document 2 Japanese patent application laid-open No. 2014-98487 Disclosure of Invention Problems to be solved by the invention When performing control for limiting the operation of a work implement (front implement) to a predetermined area (hereinafter referred to as "area limiting control of the work implement") as in the area limiting excavation control device described in patent document 1, in order to improve the accuracy of flow rate control for driving a hydraulic actuator of the work implement, it is considered to apply the technique described in patent document 2 in which the opening area of a flow rate control valve (adjustment valve) is adjusted