Construction machinery control device and construction machinery

Abstract

The present invention provides a construction machinery control device and construction machinery that can accurately move the tip attachment close to the target construction surface in an automated control system. [Solution] The construction machine control device is a control device for a construction machine 1 comprising a work device 4 including a boom 6, an arm 7 rotatably connected to the tip of the boom 6, and a tip attachment 8 rotatably connected to the tip of the arm 7. The construction machine control device comprises a controller 70 that performs automatic control of the work device 4 to move the tip attachment 8 toward a preset target construction surface. The controller 70 continues the automatic control until the speed of a specific part of the work device 4, or a specific value correlated with this speed, falls below a specific threshold, which is a threshold for determining when to stop the operation of the work device 4.

Description

Technical Field

[0001] The present disclosure relates to a control device for a construction machine having an automatic control function.

Background Art

[0002] The working machine of Patent Document 1 includes a working device having a bucket, a first hydraulic actuator that drives the working device, an operating device that outputs a first control signal of the first hydraulic actuator according to an operator's operation, information on a target construction surface that is the target shape of the working object of the working device is stored, and a control device that calculates a second control signal for operating the first hydraulic actuator so that the working device is located above the target construction surface, and a switching device in which either one of an ON position and an OFF position can be selected. When the switching device is switched to the ON position, the control device outputs either one of the first control signal and the second control signal to control the operation of the first hydraulic actuator. When the switching device is switched to the OFF position, the control device outputs the first control signal to control the operation of the first hydraulic actuator. The control device stores a table defining the relationship between the target construction surface distance, which is the distance between the bucket and the target construction surface, and a limit value of the time change rate of the switching of the control signal for operating the first hydraulic actuator when the switching device switches from the OFF position to the ON position or from the ON position to the OFF position. The control device limits the time change rate of the switching of the control signal of the first hydraulic actuator when the switching device switches from the OFF position to the ON position or from the ON position to the OFF position to a predetermined time change rate limit value determined from the target construction surface distance and the table. Patent Document 1 describes that since the time change rate of the switching of the control signal of the first hydraulic actuator when the switching device switches from the ON position to the OFF position is limited to the predetermined time change rate limit value, a sudden change in the actuator speed is suppressed.

Prior Art Documents

Patent Documents

[0003] [Patent Document 1] Patent No. 6966312 [Overview of the project] [Problems that the invention aims to solve]

[0004] However, in the technology described in Patent Document 1, when the switching device is switched from the ON position to the OFF position, the first control signal, which is the pilot pressure generated by the operating lever, is issued instead of the second control signal that operates the first hydraulic actuator so that the work device is positioned above the target construction surface. In other words, when the switching device is switched from the ON position to the OFF position, automatic control is not performed to operate the first hydraulic actuator so that the work device is positioned above the target construction surface. Instead, control is performed based on the first control signal that responds to the operator's operation of the operating lever. As a result, it may not be possible to accurately move the tip attachment, such as a bucket, close to the target construction surface. In this case, construction accuracy cannot be maintained.

[0005] This disclosure was made to solve the above-mentioned problems, and its purpose is to provide a control device for construction machinery that can accurately move the tip attachment close to the target construction surface in automatic control. [Means for solving the problem]

[0006] A construction machine control device according to the first embodiment is a control device for a construction machine comprising a work device including a boom, an arm rotatably connected to the tip of the boom, and a tip attachment rotatably connected to the tip of the arm, wherein the construction machine control device includes a controller that performs automatic control of the work device to move the tip attachment toward a preset target construction surface, and the controller continues the automatic control until the speed of a specific part of the work device or a specific value correlated with this speed falls below a specific threshold, which is a threshold for determining when to stop the operation of the work device.

[0007] According to the first embodiment, the controller continues the automatic control until the specific value (i.e., the speed of a specific part of the work device or a value correlated with this speed) falls below the specific threshold, which is a threshold for determining when to stop the operation of the work device. This allows the tip attachment to be moved accurately to the target construction surface. This prevents the tip attachment from going beyond the target construction surface, or in other words, from passing the target construction surface, making it easier to maintain the construction accuracy of the construction surface.

[0008] A construction machinery control device according to a second embodiment preferably has the following additional features compared to a construction machinery control device according to a first embodiment: The construction machinery control device according to a second embodiment includes an arm operating member that receives arm operation by an operator for moving the arm, the specific part is the arm, the specific value is the speed of the arm or an arm specific value which is correlated with this speed, the controller is configured to control the movement of the arm, the movement of the boom and the movement of the tip attachment based on the arm operation in the automatic control, and the controller terminates the automatic control when the arm specific value falls below the specific threshold.

[0009] In the second embodiment, the arm specific value (i.e., the speed of the arm or a value correlated with this speed), which is the output of the control based on the arm operation by the operator, is included in the conditions for terminating the automatic control. The automatic control continues if the arm specific value is greater than the specific threshold as the operator continues the arm operation, and the automatic control terminates when the arm specific value falls below the specific threshold as the operator stops the arm operation. In other words, in the second embodiment, the operator can continue the automatic control while performing the arm operation, and this automatic control can accurately move the tip attachment close to the target construction surface.

[0010] A construction machinery control device according to a third embodiment preferably comprises the following additional configurations in addition to the construction machinery control device according to a second embodiment. In the third embodiment, the controller calculates an arm operation command value, which is a command value for moving the arm, based on the amount of arm operation, and calculates a boom operation command value, which is a command value for moving the boom, such that the speed of the boom decreases as the height deviation, which is the deviation between the height of the target construction surface and the height of the tip attachment, decreases.

[0011] In the third embodiment, in the automatic control, as the height deviation decreases, that is, as the tip attachment approaches the target construction surface, the boom speed decreases, making it easier for the operator to time the stopping of the arm operation when the tip attachment moves close to the target construction surface. This allows the tip attachment to be moved closer to the target construction surface with even greater precision in the automatic control.

[0012] In this third embodiment, the controller may calculate not only the boom operation command value but also the tip attachment operation command value, which is a command value for moving the tip attachment, such that the speed of the tip attachment decreases as the height deviation decreases.

[0013] A construction machinery control device according to the fourth embodiment preferably has the following additional features compared to a construction machinery control device according to the first embodiment. In other words, the construction machine control device according to the fourth embodiment further comprises an arm operating member that receives arm operation by an operator to move the arm, the specific part is the arm, the specific value is an arm specific value which is the speed of the arm or a value correlated with this speed, or an arm target value which is a target value for the speed of the arm or a value correlated with this target value, the controller executes the automatic control when the amount of operation of the arm is greater than a predetermined first operation amount threshold, the controller calculates the arm target value based on the amount of operation of the arm, calculates a boom target value which is a target value for the speed of the boom or a value correlated with this target value based on the amount of operation of the arm or the arm target value, the controller calculates the arm target value such that the arm target value gradually decreases based on predetermined conditions when the amount of operation of the arm becomes less than or equal to a second operation amount threshold which is less than the first operation amount threshold, the controller terminates the automatic control when the arm specific value or the arm target value becomes less than or equal to the specific threshold.

[0014] As in the fourth embodiment, the controller may perform feedforward control, calculating the arm target value based on the amount of arm operation, and calculating the boom target value based on the amount of arm operation or the arm target value. In such feedforward control, even when the amount of arm operation becomes zero, the arm and boom may not be able to stop instantaneously due to inertia. Therefore, in this fourth embodiment, the arm target value is calculated such that when the amount of arm operation becomes less than or equal to a second operation threshold which is smaller than the first operation threshold, the arm target value gradually decreases based on predetermined conditions. In this case, when the amount of arm operation becomes less than or equal to the second operation threshold, the arm target value gradually decreases, and the boom target value also gradually decreases. As a result, the amount of arm operation becomes even smaller than the second operation threshold, making it possible to keep the speed of the arm and the boom at the point when it becomes zero relatively small. Therefore, the arm and the boom can be stopped at a relatively early stage after the amount of arm operation becomes zero. This prevents the tip attachment from exceeding the target construction surface, or in other words, from passing over the target construction surface, thus making it easier to maintain the construction accuracy of the construction surface.

[0015] In this fourth embodiment, the controller may, in the feedforward control, calculate not only the boom target value, but also a target value for the speed of the tip attachment or a tip attachment target value which is a value correlated with this target value, using the amount of arm operation or the arm target value.

[0016] The construction machine according to the fifth embodiment comprises the work device and a construction machine control device according to any one of the first to fourth embodiments.

[0017] According to the fifth aspect, since the controller continues the automatic control until the specific value becomes less than or equal to the specific threshold value that is the threshold value for determining the stop of the operation of the working device, the tip attachment can be accurately moved close to the target construction surface. As a result, it is possible to suppress a situation where the tip attachment exceeds the target construction surface, or in other words, a situation where the tip attachment passes through the target construction surface, so that the construction accuracy of the construction surface is likely to be maintained.

Effects of the Invention

[0018] According to the present disclosure, there are provided a construction machine control device and a construction machine capable of accurately moving a tip attachment close to a target construction surface in automatic control.

Brief Description of the Drawings

[0019] [Figure 1] FIG. 1 is a side view showing an example of a construction machine according to an embodiment of the present disclosure. [Figure 2] FIG. 2 is a diagram for explaining the system structure of the construction machine of FIG. 1. [Figure 3] FIG. 3 is a flowchart for explaining a first control example of moving a bucket toward a target construction surface. [Figure 4] FIG. 4 is a flowchart for explaining a second control example of moving a bucket toward a target construction surface.

Modes for Carrying Out the Invention

[0020] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. FIG. 1 is a side view showing an example of a construction machine 1 according to an embodiment of the present disclosure. The construction machine 1 shown in FIG. 1 is a hydraulic excavator.

[0021] The construction machine 1 includes a lower traveling body 2, an upper slewing body 3 that is rotatably supported on the lower traveling body 2, and a working device 4 that is mounted on the upper slewing body 3 so as to be able to rise and fall. The lower traveling body 2 has crawlers 2a, but may have tires (not shown). The upper slewing body 3 has a slewing frame 3a supported by the lower traveling body 2, a cab disposed on the slewing frame 3a, and a counterweight. The working device 4 includes a boom 6, an arm 7 rotatably connected to the tip of the boom 6, and a bucket 8 rotatably connected to the tip of the arm 7. The bucket 8 is an example of a tip attachment.

[0022] FIG. 2 is a diagram for explaining the system structure of the construction machine 1. The construction machine 1 includes a plurality of hydraulic actuators that operate the working device 4 and the upper slewing body 3, a plurality of operation members 19 that receive operations for operating the working device 4 and the upper slewing body 3, a hydraulic pump 15 for supplying hydraulic oil to the plurality of hydraulic actuators, a pilot pump 16, a control valve 23 for switching the supply path of the hydraulic oil supplied to each of the plurality of hydraulic actuators, and a construction machine control device. The construction machine control device includes a controller 70. The control valve 23 includes a plurality of proportional valves 20 and a plurality of direction switching valves 22.

[0023] In the present embodiment, the plurality of hydraulic actuators include a boom cylinder 9 for rotating the boom 6, an arm cylinder 10 for rotating the arm 7, a bucket cylinder 11 for rotating the bucket 8, a slewing motor 12 for slewing the upper slewing body 3, and a traveling motor (not shown). The plurality of actuators operate by being supplied with hydraulic oil discharged from the hydraulic pump 15.

[0024] The boom 6 is rotatably mounted to the upper slewing body 3 and performs a luffing motion relative to the upper slewing body 3 in conjunction with the extension and retraction of the boom cylinder 9. Specifically, when the boom cylinder 9 is retracted, the boom 6 performs a boom-lowering motion in which the tip of the boom 6 moves closer to the ground G. When the boom cylinder 9 is extended, the boom 6 performs a boom-raising motion in which the tip of the boom 6 moves away from the ground G.

[0025] Arm 7 is rotatably attached to the tip of boom 6 and rotates relative to boom 6 in conjunction with the extension and retraction of arm cylinder 10. Specifically, when arm cylinder 10 is retracted, arm 7 performs an arm pushing motion, moving its tip away from boom 6. When arm cylinder 10 is extended, arm 7 performs an arm pulling motion, moving its tip closer to boom 6.

[0026] Bucket 8 is rotatably attached to the tip of arm 7 and rotates relative to arm 7 in conjunction with the extension and retraction of bucket cylinder 11. Specifically, when bucket cylinder 11 is retracted, bucket 8 performs a bucket soil discharge operation (bucket pushing operation). Bucket soil discharge operation is the operation of discharging held material such as soil held in bucket 8 to a destination such as the bed of a truck. When bucket cylinder 11 is extended, bucket 8 performs a bucket digging operation (bucket pulling operation). Bucket digging operation is the operation of excavating an object to be excavated, such as ground, using bucket 8.

[0027] The upper rotating body 3 performs a rotational movement (right rotation or left rotation) around a vertical axis relative to the lower traveling body 2 in accordance with the operation of the rotation motor 12. The lower traveling body 2 performs a traveling movement along the ground in accordance with the operation of the traveling motor.

[0028] The multiple operating members 19 include multiple members that receive various operations from the operator. Specifically, for example, the multiple operating members 19 may include a boom operating member 19a for operating the boom 6, an arm operating member 19b for operating the arm 7, a bucket operating member 19c for operating the bucket 8, a slewing operating member 19d for performing a slewing operation of the upper slewing body 3, and a travel operating member 19e for operating the travel of the lower travel body 2. Each of the multiple operating members 19 may be an operating lever or an operating pedal.

[0029] The boom operating member 19a receives boom operation by the operator. The boom operation is either a boom lowering operation or a boom raising operation. The boom lowering operation is an operation to cause the boom 6 to perform a boom lowering movement, and the boom raising operation is an operation to cause the boom 6 to perform a boom raising movement. The arm operating member 19b receives arm operation by the operator. The arm operation is either an arm pushing operation or an arm pulling operation. The arm pushing operation is an operation to cause the arm 7 to perform an arm pushing movement, and the arm pulling operation is an operation to cause the arm 7 to perform an arm pulling movement. The bucket operating member 19c receives bucket operation by the operator. The bucket operation is either a bucket soil removal operation or a bucket excavation operation. The bucket soil removal operation is an operation to cause the bucket 8 to perform a bucket soil removal operation, and the bucket excavation operation is an operation to cause the bucket 8 to perform a bucket excavation operation. The slewing operating member 19d receives slewing operation by the operator. The slewing operation is either a right slewing operation or a left slewing operation. The right turn operation is an operation to cause the upper rotating body 3 to perform a right turn, and the left turn operation is an operation to cause the upper rotating body 3 to perform a left turn. The travel operation member 19e receives travel operations from the operator to move the lower traveling body 2.

[0030] The construction machine 1 is equipped with a plurality of operation detectors 21. The plurality of operation detectors 21 include a boom operation detector 21a, an arm operation detector 21b, a bucket operation detector 21c, a slewing operation detector 21d, and a travel operation detector 21e. The boom operation detector 21a detects the boom operation amount Lbm for boom lowering and boom raising operations received by the boom operation member 19a. The arm operation detector 21b detects the arm operation amount La for arm pushing and arm pulling operations received by the arm operation member 19b. The bucket operation detector 21c detects the bucket operation amount Lbk for bucket soil removal and bucket excavation operations received by the bucket operation member 19c. The slewing operation detector 21d detects the slewing operation amount Lsw for right slewing and left slewing operations received by the slewing operation member 19d. The travel operation detector 21e detects the amount of travel operation received by the travel operation member 19e. Each of the multiple operation detectors 21 inputs the detection result to the controller 70. The slewing operation member 19d is an example of an operation member for performing the slewing operation of the upper slewing body of this disclosure.

[0031] The construction machine 1 may be equipped with a remote control valve that outputs a pilot pressure (secondary pressure) corresponding to the amount of operation received by the operating member 19. In this case, each of the multiple operation detectors 21 may be a pressure sensor that detects the pilot pressure corresponding to the amount of operation.

[0032] The hydraulic pump 15 supplies hydraulic fluid to at least one of the plurality of hydraulic actuators. The hydraulic pump 15 may consist of only one hydraulic pump, or it may include multiple hydraulic pumps (for example, two hydraulic pumps). The hydraulic pump 15 discharges hydraulic fluid when driven by the engine 5. The pilot pump 16 discharges hydraulic fluid supplied to each of the plurality of directional control valves 22 when driven by the engine 5.

[0033] The multiple proportional valves 20 may include a first boom proportional valve 20a, a second boom proportional valve 20b, a first arm proportional valve 20c, a second arm proportional valve 20d, a first bucket proportional valve 20e, a second bucket proportional valve 20f, a first swing proportional valve 20g, and a second swing proportional valve 20h. Each of the multiple proportional valves 20 is an electromagnetic proportional valve that outputs a secondary pressure (pilot pressure) in accordance with a command (current command value) input from the controller 70.

[0034] The multiple directional control valves 22 may include a boom directional control valve 22a, an arm directional control valve 22b, a bucket directional control valve 22c, and a slewing directional control valve 22d.

[0035] The boom direction switching valve 22a switches the direction in which the hydraulic fluid discharged from the hydraulic pump 15 is supplied to the boom cylinder 9. The boom direction switching valve 22a has a spool that moves in accordance with the first pilot pressure output from the first boom proportional valve 20a and the second pilot pressure output from the second boom proportional valve 20b. The boom direction switching valve 22a has a first pilot port that receives the first pilot pressure from the first boom proportional valve 20a and a second pilot port that receives the second pilot pressure from the second boom proportional valve 20b.

[0036] For example, when the controller 70 inputs a boom-raising command (current command value) to the first boom proportional valve 20a, a first pilot pressure corresponding to the boom-raising command is supplied from the first boom proportional valve 20a to the first pilot port, and the boom direction switching valve 22a opens to allow hydraulic fluid to be supplied to the head side chamber of the boom cylinder 9 and to allow the hydraulic fluid discharged from the rod side chamber of the boom cylinder 9 to return to the tank. As a result, the boom cylinder 9 extends at a speed corresponding to the boom-raising command, and the boom 6 performs a boom-raising operation at a speed corresponding to the boom-raising command. Also, when the controller 70 inputs a boom-down command (current command value) to the second boom proportional valve 20b, a second pilot pressure corresponding to the boom-down command is supplied from the second boom proportional valve 20b to the second pilot port, and the boom direction switching valve 22a opens to allow hydraulic fluid to be supplied to the rod side chamber of the boom cylinder 9 and to allow the hydraulic fluid discharged from the head side chamber of the boom cylinder 9 to return to the tank. As a result, the boom cylinder 9 retracts at a speed corresponding to the boom lowering command, and the boom 6 performs a boom lowering operation at a speed corresponding to the boom lowering command.

[0037] The arm direction switching valve 22b switches the direction in which the hydraulic fluid discharged from the hydraulic pump 15 is supplied to the arm cylinder 10. The arm direction switching valve 22b has a spool that moves in accordance with the first pilot pressure output from the first arm proportional valve 20c and the second pilot pressure output from the second arm proportional valve 20d. The arm direction switching valve 22b has a first pilot port that receives the first pilot pressure from the first arm proportional valve 20c and a second pilot port that receives the second pilot pressure from the second arm proportional valve 20d.

[0038] For example, when the controller 70 inputs an arm pull command (current command value) to the first arm proportional valve 20c, a first pilot pressure corresponding to the arm pull command is supplied from the first arm proportional valve 20c to the first pilot port, and the arm direction switching valve 22b opens to allow hydraulic fluid to be supplied to the head side chamber of the arm cylinder 10 and to allow the hydraulic fluid discharged from the rod side chamber of the arm cylinder 10 to return to the tank. As a result, the arm cylinder 10 extends at a speed corresponding to the arm pull command, and the arm 7 performs an arm pull operation at a speed corresponding to the arm pull command. Also, when the controller 70 inputs an arm push command (current command value) to the second arm proportional valve 20d, a second pilot pressure corresponding to the arm push command is supplied from the second arm proportional valve 20d to the second pilot port, and the arm direction switching valve 22b opens to allow hydraulic fluid to be supplied to the rod side chamber of the arm cylinder 10 and to allow the hydraulic fluid discharged from the head side chamber of the arm cylinder 10 to return to the tank. As a result, the arm cylinder 10 retracts at a speed corresponding to the arm pushing command, and the arm 7 performs an arm pushing operation at a speed corresponding to the arm pushing command.

[0039] The bucket directional control valve 22c switches the direction in which the hydraulic fluid discharged from the hydraulic pump 15 is supplied to the bucket cylinder 11. The bucket directional control valve 22c has a spool that moves in accordance with a first pilot pressure output from the first bucket proportional valve 20e and a second pilot pressure output from the second bucket proportional valve 20f. The bucket directional control valve 22c has a first pilot port that receives the first pilot pressure from the first bucket proportional valve 20e and a second pilot port that receives the second pilot pressure from the second bucket proportional valve 20f.

[0040] For example, when the controller 70 inputs a bucket pull command (current command value) to the first bucket proportional valve 20e, a first pilot pressure corresponding to the bucket pull command is supplied from the first bucket proportional valve 20e to the first pilot port, and the bucket directional control valve 22c opens to allow hydraulic fluid to be supplied to the head side chamber of the bucket cylinder 11 and to allow the hydraulic fluid discharged from the rod side chamber of the bucket cylinder 11 to return to the tank. As a result, the bucket cylinder 11 extends at a speed corresponding to the bucket pull command, and the bucket 8 performs a bucket pull operation at a speed corresponding to the bucket pull command. Also, when the controller 70 inputs a bucket push command (current command value) to the second bucket proportional valve 20f, a second pilot pressure corresponding to the bucket push command is supplied from the second bucket proportional valve 20f to the second pilot port, and the bucket directional control valve 22c opens to allow hydraulic fluid to be supplied to the rod side chamber of the bucket cylinder 11 and to allow the hydraulic fluid discharged from the head side chamber of the bucket cylinder 11 to return to the tank. As a result, the bucket cylinder 11 retracts at a speed corresponding to the bucket pushing command, and the bucket 8 performs a bucket pushing operation at a speed corresponding to the bucket pushing command.

[0041] The swivel direction switching valve 22d switches the direction in which the hydraulic fluid discharged from the hydraulic pump 15 is supplied to the swivel motor 12. The swivel direction switching valve 22d has a spool that moves in accordance with a first pilot pressure Ppi1 output from a first swivel proportional valve 20g and a second pilot pressure Ppi2 output from a second swivel proportional valve 20h. The swivel direction switching valve 22d has a first pilot port that receives the first pilot pressure Ppi1 from the first swivel proportional valve 20g and a second pilot port that receives the second pilot pressure Ppi2 from the second swivel proportional valve 20h.

[0042] For example, when the controller 70 inputs a left turn command (current command value) to the first swing proportional valve 20g, the first pilot pressure Ppi1 corresponding to the left turn command is supplied from the first swing proportional valve 20g to the first pilot port, and the swing direction switching valve 22d opens to allow hydraulic fluid to be supplied to the first port of the swing motor 12 and to allow the hydraulic fluid discharged from the second port of the swing motor 12 to return to the tank. As a result, the swing motor 12 swings to the left at a speed corresponding to the left turn command, and the upper swing body 3 performs a left turn operation at a speed corresponding to the left turn command. Furthermore, when the controller 70 inputs a right-turn command (current command value) to the second swing proportional valve 20h, the second pilot pressure Ppi2 corresponding to the right-turn command is supplied from the second swing proportional valve 20h to the second pilot port, and the swing direction switching valve 22d opens to allow hydraulic fluid to be supplied to the second port of the swing motor 12 and to allow the hydraulic fluid discharged from the first port of the swing motor 12 to return to the tank. As a result, the swing motor 12 swings to the right at a speed corresponding to the right-turn command, and the upper swing body 3 performs a right-turn operation at a speed corresponding to the right-turn command.

[0043] The controller 70 has a computer that includes an arithmetic processing unit and memory. The controller 70 controls the operation of the construction machine 1 by having the arithmetic processing unit execute a program stored in memory.

[0044] The construction machine 1 is equipped with multiple angle sensors 24. The controller 70 receives the detected values ​​(angles) from the multiple angle sensors 24. The multiple angle sensors 24 include first to fifth angle sensors. The first angle sensor 24a detects the boom angle θa of the boom 6. The second angle sensor 24b detects the arm angle θb of the arm 7. The third angle sensor 24c detects the bucket angle θc of the bucket 8. The fourth angle sensor 24d detects the slewing angle θd of the slewing motor 12 that slewing the upper slewing body 3. The fifth angle sensor 24e detects the inclination angle θe of the construction machine 1. The inclination angle θe may be, for example, the inclination angle of the lower traveling body 2 or the upper slewing body 3 with respect to the horizontal plane.

[0045] Furthermore, the construction machine 1 may be equipped with multiple pressure sensors 25 (hydraulic sensors). In this case, the controller 70 receives the detected values ​​(pressures) detected by the multiple pressure sensors 25. The multiple pressure sensors 25 include the first to eighth pressure sensors. The first pressure sensor 25a and the second pressure sensor 25b detect the pressure in the head side chamber and the rod side chamber of the boom cylinder 9, respectively. The third pressure sensor 25c and the fourth pressure sensor 25d detect the pressure in the head side chamber and the rod side chamber of the arm cylinder 10, respectively. The fifth pressure sensor 25e and the sixth pressure sensor 25f detect the pressure in the head side chamber and the rod side chamber of the bucket cylinder 11, respectively. The seventh pressure sensor 25g detects the hydraulic fluid pressure at one port of the slewing motor 12, and the eighth pressure sensor 25h detects the hydraulic fluid pressure at the other port of the slewing motor 12.

[0046] Furthermore, the construction machine 1 may be equipped with multiple speed sensors 26. In this case, the controller 70 receives a detected value (speed V) detected by the multiple speed sensors 26. The multiple speed sensors 26 include first to fourth speed sensors. The first speed sensor 26a detects the boom speed Vbm. The boom speed Vbm is the speed of the boom 6 or the speed of the boom cylinder 9, which is a value correlated with that speed. The second speed sensor 26b detects the arm speed Va. The arm speed Va is the speed of the arm 7 or the speed of the arm cylinder 10, which is a value correlated with that speed. The third speed sensor 26c detects the bucket speed Vbk. The bucket speed Vbk is the speed of the bucket 8 or the speed of the bucket cylinder 11, which is a value correlated with that speed. The fourth speed sensor 26d detects the slewing speed Vsw. The slewing speed Vsw is the slewing speed of the upper slewing body 3 or the speed of the slewing motor 12, which is a value correlated with that slewing speed. The arm velocity Va is an example of a specific value in this disclosure.

[0047] Furthermore, the construction machine 1 is equipped with a machine control switch 28 (hereinafter referred to as MC switch 28). The controller 70 receives an on / off switching signal output from the MC switch 28. The MC switch 28 may be, for example, a switch displayed on a touch panel, or a mechanical switch such as a seesaw switch. The MC switch 28 can be switched by the operator and can be switched during operation of the operating member 19. The MC switch 28 does not necessarily have to be a switch displayed on a touch panel or a seesaw switch; it may be any switching device that can switch the automatic control on and off as described later.

[0048] The MC switch 28 is a switch for switching between automatic control of the work device 4 by the controller 70 and normal control in response to manual operation by the operator. When the MC switch 28 is switched to the ON position, the controller 70 switches the control mode of the construction machine 1 to the automatic control mode, and when the MC switch 28 is switched to the OFF position, the controller 70 switches the control mode to the manual operation mode.

[0049] Construction machine 1 is equipped with a target construction surface setting device 30. The target construction surface setting device 30 is a device for setting a target construction surface that will be used as the target when performing automatic control. The target construction surface setting device 30 may include an imaging device such as a camera that captures images of the work site, and a monitor that displays the images captured by the imaging device. The monitor may be a monitor that is pre-installed inside the cab. The target construction surface setting device 30 is operated by the operator before work begins.

[0050] The operator displays an image of the work site captured by the imaging device of the target construction surface setting device 30 on the monitor. Next, the operator sets the target construction surface on the monitor. For example, if the operator specifies two points on the monitor, the target construction surface setting device 30 sets the target construction surface based on the specified points. Specifically, for example, if the operator specifies two points on the monitor, the target construction surface setting device 30 sets the line connecting the two specified points as the target construction surface. Alternatively, the operator may specify three points on the monitor, in which case the target construction surface setting device 30 may set the plane containing the three specified points as the target construction surface. The target construction surface setting device 30 stores the set target construction surface and inputs it to the controller 70. Note that the method of setting the target construction surface is not limited to the above. For example, after the operator moves the tip of the bucket 8 to a position that should be included in the target construction surface by operating the operating member 19, the operator performs an input operation to the target construction surface setting device 30, and the target construction surface setting device 30 stores the position (coordinates) of the tip of the bucket 8. By repeating this process multiple times, the target construction surface setting device 30 can store multiple positions (coordinates) that are included in the target construction surface, and may set the target construction surface based on these multiple positions (coordinates). Alternatively, the target construction surface setting device 30 may set the target construction surface based on data read from a storage medium that stores data related to the target construction surface.

[0051] When the MC switch 28 is switched from the off position to the on position, the controller 70 automatically controls the movement of the arm 7, the boom 6, and the bucket 8 so that the bucket 8 moves to a preset target construction surface, based on the arm operation amount La, which is the amount of arm operation received by the arm operating member 19b. In this embodiment, since automatic control is performed, the operator can move the bucket 8 toward the target construction surface by operating only the arm operating member 19b, without operating the boom operating member 19a and the bucket operating member 19c, thereby reducing the burden on the operator.

[0052] When the MC switch 28 is switched to the ON position, the controller 70 starts automatic control to move the bucket 8 to the target construction surface based on the arm operation amount La of the arm operating member 19b. For example, the controller 70 calculates the position of the bucket 8 (for example, the position of the tip of the bucket 8) from the boom angle θa, arm angle θb, bucket angle θc, slewing angle θsw, vehicle body inclination angle θe, etc. This allows the controller 70 to obtain information about the relative position between the target construction surface and the bucket 8. The controller 70 may specify the position of the bucket 8 and the target construction surface using coordinates in a predetermined coordinate system. The predetermined coordinate system may be a coordinate system with a specific part of the construction machine 1 as the origin, a coordinate system with a specific location at the work site as the origin, or a global coordinate system.

[0053] The information regarding the relative position may include a height deviation e, which is the difference between the height of the target construction surface and the height of the bucket 8. The height deviation e may be the distance between the height of the target construction surface set on the ground G and the height of the tip of the bucket 8 (the cutting edge of the bucket 8), as shown in Figure 1, for example. The information regarding the relative position may also include the coordinates of the tip of the bucket 8 and information that identifies the target construction surface. The information that identifies the target construction surface may include an equation that represents the target construction surface. If the target construction surface is a plane, the equation that represents the target construction surface may be a plane equation. If the target construction surface is a horizontal plane, the information that identifies the target construction surface may include information about the height of the target construction surface.

[0054] The controller 70 can determine the position (coordinates) of the bucket 8 in a predetermined coordinate system based on the detected values ​​from the multiple angle sensors 24. Based on the determined position of the bucket 8 and the information identifying the target construction surface, the controller 70 can calculate the height deviation e.

[0055] The controller 70 may control the boom cylinder 9, arm cylinder 10, and bucket cylinder 11 so that the bucket 8 moves toward the target construction surface based on the relative position.

[0056] [First control example: Feedforward control and feedback control] The controller 70 may perform the following feedforward control and feedback control in the automatic control. For example, in the automatic control, the controller 70 may calculate an arm target value based on the arm operating amount La of the arm operating member 19b, perform feedforward control to operate the arm cylinder 10 based on this arm target value, and perform feedback control to operate the boom cylinder 9 and bucket cylinder 11 based on the height deviation e. The arm target value may be a target value for the speed of the arm 7 (arm target speed), or it may be a target value for the operating speed of the arm cylinder 10 (arm target speed), which is a value correlated with this target value.

[0057] In this case, the controller 70 may store in advance maps such as relational expressions and lookup tables that represent the relationship between the arm operating amount La and the arm target value, and the controller 70 may calculate the arm target value corresponding to the arm operating amount La by applying the arm operating amount La to the map. The relational expression may be, for example, equation (3) described later. The controller 70 inputs an arm operation command value Ia corresponding to the arm target value to the arm proportional valve (first arm proportional valve 20c or second arm proportional valve 20d). As a result, the arm cylinder 10 operates at a speed corresponding to the arm operating amount La. In this case, the controller 70 may store in advance maps such as relational expressions and lookup tables that represent the relationship between the arm target value and the arm operation command value Ia, and the controller 70 may calculate the arm operation command value Ia corresponding to the arm target value by applying the arm target value to the map.

[0058] Furthermore, the controller 70 calculates a boom operation command value Ibm and a bucket operation command value Ibk according to the height deviation e, inputs the boom operation command value Ibm to the boom proportional valve (first boom proportional valve 20a or second boom proportional valve 20b), and inputs the bucket operation command value Ibk to the bucket proportional valve (first bucket proportional valve 20e or second bucket proportional valve 20f). As a result, the boom cylinder 9 and the bucket cylinder 11 each operate at a speed corresponding to the height deviation e. In this case, the controller 70 may pre-store a map such as a relational expression or lookup table that represents the relationship between the height deviation e and the boom operation command value Ibm, and the controller 70 may calculate the boom operation command value Ibm according to the height deviation e by applying the height deviation e to the said map. Similarly, the controller 70 may pre-store maps such as relational expressions and lookup tables that represent the relationship between the height deviation e and the bucket operation command value Ibk, and the controller 70 may calculate the bucket operation command value Ibk corresponding to the height deviation e by applying the height deviation e to the said map. The bucket operation command value Ibk is an example of an end attachment command value.

[0059] [Second control example: Feedforward control] Furthermore, the controller 70 may perform the following feedforward control in the automatic control. For example, in the automatic control, the controller 70 may calculate the arm target value based on the arm operating amount La, calculate the boom target value and bucket target value based on the arm operating amount La or the arm target value, and perform feedforward control to operate the boom cylinder 9, arm cylinder 10 and bucket cylinder 11 based on the boom target value, arm target value and bucket target value. The boom target value may be the target value of the boom 6 speed, or it may be the target value of the operating speed of the boom cylinder 9, which is a value correlated with this target value. The bucket target value may be the target value of the bucket 8 speed, or it may be the target value of the operating speed of the bucket cylinder 11, which is a value correlated with this target value.

[0060] In this case, the controller 70 may store in advance maps such as relational expressions representing the relationship between the arm operating amount La or the arm target value and the boom target value, or lookup tables, and the controller 70 may calculate the boom target value corresponding to the arm operating amount La by applying the arm operating amount La or the arm target value to the map. Similarly, the controller 70 may store in advance maps such as relational expressions representing the relationship between the arm operating amount La or the arm target value and the bucket target value, or lookup tables, and the controller 70 may calculate the bucket target value corresponding to the arm operating amount La by applying the arm operating amount La or the arm target value to the map. The controller 70 then inputs an arm operation command value Ia corresponding to the arm target value to the arm proportional valve (first arm proportional valve 20c or second arm proportional valve 20d), a boom operation command value Ibm corresponding to the boom target value to the boom proportional valve (first boom proportional valve 20a or second boom proportional valve 20b), and a bucket operation command value Ibk corresponding to the bucket target value to the bucket proportional valve (first bucket proportional valve 20e or second bucket proportional valve 20f). As a result, the arm cylinder 10, boom cylinder 9, and bucket cylinder 11 each operate at a speed corresponding to the arm operation amount La. In this case, the controller 70 may pre-store a map such as a relational expression or lookup table that represents the relationship between the arm target value and the arm operation command value Ia, and the controller 70 may calculate the arm operation command value Ia corresponding to the arm target value by applying the arm target value to the map. Similarly, the controller 70 may pre-store a map representing the relationship between the boom target value and the boom operation command value Ibm, and a map representing the relationship between the bucket target value and the bucket operation command value Ibk. The controller 70 may then use these maps, the boom target value, and the bucket target value to calculate the boom operation command value Ibm and the bucket operation command value Ibk.

[0061] Of the two control examples described above, the first example will be explained in detail first, and then the second example will be explained in detail.

[0062] [First control example] In the automatic control, the controller 70 calculates the arm target value according to the arm operating amount La, and calculates the arm operation command value Ia according to the arm target value. In addition, in the automatic control, the controller 70 calculates the boom operation command value Ibm such that the speed of the boom 6 decreases as the height deviation e decreases, and calculates the bucket operation command value Ibk such that the speed of the bucket 8 decreases as the height deviation e decreases. Specifically, in the automatic control, the controller 70 calculates the boom operation command value Ibm from the following equation (1). In equation (1), Kp1 is a proportionality constant used when calculating the boom operation command value Ibm. Similarly, in the automatic control, the controller 70 calculates the bucket operation command value Ibk from the following equation (2). In equation (2), Kp2 is a proportionality constant used when calculating the bucket operation command value Ibk.

[0063] Ibm = Kp1 × e ···(1) Ibk = Kp² × e ···(2)

[0064] From equations (1) and (2), the boom operation command value Ibm and the bucket operation command value Ibk are proportional to the deviation e. As bucket 8 approaches the target construction surface, the boom operation command value Ibm and the bucket operation command value Ibk decrease. As a result, as bucket 8 approaches the target construction surface, the boom speed Vbm of boom 6 and the bucket speed Vbk of bucket 8, i.e., the operating speed of boom cylinder 9 and bucket cylinder 11, decrease. Consequently, as bucket 8 approaches the target construction surface, the boom speed Vbm and bucket speed Vbk decrease, allowing bucket 8 to be moved onto the target construction surface with high precision.

[0065] Incidentally, during the execution of automatic control to move bucket 8 toward the target construction surface, the MC switch 28 may be switched from the ON position to the OFF position. If automatic control is terminated at this point, it may become difficult to move bucket 8 accurately onto the target construction surface, and it may become difficult to maintain the construction accuracy of the construction machine 1.

[0066] In contrast, in this embodiment, if the MC switch 28 is switched from the ON position to the OFF position while automatic control is being executed, the controller 70 cancels automatic control and switches to manual operation on the condition that the speed Va of the arm 7 becomes less than or equal to a predetermined speed threshold Vth. The speed threshold Vth is determined in advance experimentally or by design and is set to a value (zero or a value close to zero) that allows it to be determined that the arm 7 is in a stopped state. In this embodiment, the arm 7 is an example of a specific part in this disclosure, and the speed threshold Vth is an example of a specific threshold in this disclosure.

[0067] When the MC switch 28 is switched from the ON position to the OFF position, the controller 70 determines whether the speed Va of the arm 7 is less than or equal to the speed threshold Vth. If the speed Va of the arm 7 is higher than the speed threshold Vth, the controller 70 continues to perform automatic control. On the other hand, when the speed Va of the arm 7 becomes less than or equal to the speed threshold Vth, the controller 70 cancels the automatic control, i.e., terminates the automatic control.

[0068] As described above, automatic control is maintained until the arm 7 is stopped or until it can be determined that the arm 7 has stopped. If the system switches to manual operation while the arm 7 is moving, the bucket 8 may not stop instantly due to the inertia of the boom 6, etc., and the bucket 8 may dig into the target construction surface. However, since automatic control is maintained until the arm 7 is stopped, the bucket 8 digging into the target construction surface due to the inertia of the boom 6, etc. is also suppressed. As a result, the construction accuracy of the construction machine 1 is maintained. In addition, since the switch to manual operation is determined based on the speed Va of the arm 7 which is being directly operated by the operator, the construction accuracy of the construction machine 1 is appropriately maintained.

[0069] Figure 3 is a flowchart illustrating the control operation when moving bucket 8 toward the target construction surface. This flowchart is executed repeatedly during the operation of construction machine 1.

[0070] First, the target construction surface is set in advance by the target construction surface setting device 30 (step S10). Next, the controller 70 determines whether or not the MC switch 28 has been switched to the ON position (step S20). If the MC switch 28 is in the OFF position (NO in step S20), the controller 70 outputs an arm operation command value Ia corresponding to the arm operation amount La of the arm operating member 19b, a boom operation command value Ibm corresponding to the boom operation amount Lbm of the boom operating member 19a, and a bucket operation command value Ibk corresponding to the bucket operation amount Lbk of the bucket operating member 19c (step S70).

[0071] On the other hand, if the MC switch 28 is in the ON position (YES in step S20), the controller 70 performs automatic control. In this case, the controller 70 calculates the height deviation e between the target construction surface and the bucket 8 (step S30). Next, the controller 70 calculates the boom operation command value Ibm and the bucket operation command value Ibk based on the height deviation e and the above-described equations (1) and (2) (step S40). The controller 70 also calculates the arm operation command value Ia based on the arm operation amount La.

[0072] Next, the controller 70 determines whether the MC switch 28 is switched to the off position and whether the speed Va of the arm 7 is less than or equal to the speed threshold Vth (step S50). If at least one of the following is true (NO in step S50), the controller 70 continues to perform automatic control and returns to step S30. On the other hand, if the MC switch 28 is switched to the off position and the speed Va of the arm 7 is less than or equal to the speed threshold Vth (YES in step S50), the controller 70 cancels automatic control and sets the boom operation command value Ibm and the bucket operation command value Ibk to zero (step S60). As a result, the boom 6 and bucket 8 stop. In step S50, if the speed Va of the arm 7 is less than or equal to the speed threshold Vth, the speed of the arm 7 is zero or nearly zero, the arm 7 is stopped or nearly stopped, and the boom 6 and bucket 8 also stop due to the processing in step S60 which is performed immediately afterward.

[0073] [Second control example] Next, we will explain a second control example.

[0074] When the MC switch 28 is switched to the ON position and the arm operating amount La is greater than a predetermined first threshold Lth1, the controller 70 calculates the arm target velocity Vatgt based on the following equation (3). In equation (3), Ka is a preset proportionality constant. The first threshold Lth1 is determined in advance experimentally or by design and is set to a threshold that indicates the operator intends to move the bucket 8. From equation (3), the arm target velocity Vatgt is a value proportional to the arm operating amount La. The arm target velocity Vatgt is an example of an arm target value in this disclosure. The first threshold Lth1 is an example of a first operating amount threshold in this disclosure.

[0075] Vatgt = Ka × La ···(3)

[0076] Furthermore, the controller 70 determines whether the arm operation amount La during the execution of automatic control is greater than the second threshold Lth2. The second threshold Lth2 is a value smaller than the first threshold Lth1 and is determined in advance experimentally or by design, and is set as a threshold that allows the controller to determine that the operator intends to stop the arm 7. Note that the second threshold Lth2 is an example of a second operation amount threshold in this disclosure.

[0077] When the arm operating amount La is greater than the second threshold Lth2, the controller 70 calculates the boom operation command value Ibm and the bucket operation command value Ibk based on the arm target speed Vatgt calculated by equation (3). Specifically, the controller 70 may geometrically calculate the boom operation command value Ibm using information that identifies the target construction surface, the dimensions of the boom 6, the dimensions of the arm 7, the dimensions of the bucket 8, the boom angle θa, the arm angle θb, the bucket angle θc, and the arm target speed Vatgt. Similarly, the controller 70 may geometrically calculate the bucket operation command value Ibk using the aforementioned parameters and the arm target speed Vatgt.

[0078] Specifically, for example, a target relative position may be set, which is the target relative position of the bucket 8 with respect to the target construction surface. The target relative position may include, for example, the target attitude of the bucket 8 with respect to the target construction surface and the target distance of the tip of the bucket 8 with respect to the target construction surface. The controller 70 can calculate the boom target speed, which is the target speed of the boom 6 required for the bucket 8 to be positioned at the target relative position, and the bucket target speed, which is the target speed of the bucket 8 required for the bucket 8 to be positioned at the target relative position, using the plurality of parameters and the arm target speed Vatgt, assuming that the arm 7 operates at the arm target speed Vatgt. The controller 70 then calculates the arm operation command value Ia, the boom operation command value Ibm, and the bucket operation command value bk, respectively, based on the arm target speed Vatgt, the boom target speed, and the bucket target speed.

[0079] Furthermore, the controller 70 may pre-store maps such as relational expressions or lookup tables that represent the relationship between the arm operating amount La or the arm target speed Vatgt and the boom target speed. In this case, the controller 70 may calculate the boom target speed by applying the arm operating amount La or the arm target speed Vatgt to the map. Similarly, the controller 70 may pre-store maps such as relational expressions or lookup tables that represent the relationship between the arm operating amount La or the arm target speed Vatgt and the bucket target speed. In this case, the controller 70 may calculate the bucket target speed by applying the arm operating amount La or the arm target speed Vatgt to the map. Then, the controller 70 calculates the arm operation command value Ia, the boom operation command value Ibm, and the bucket operation command value bk based on the arm target speed Vatgt, the boom target speed, and the bucket target speed, respectively.

[0080] The controller 70 inputs the arm operation command value Ia to the corresponding proportional valve 20 (first arm proportional valve 20c or second arm proportional valve 20d), causing a pilot pressure corresponding to the arm operation command value Ia to be output from the proportional valve 20, and the arm 7 operates at a speed corresponding to the arm operation command value Ia. Similarly, the controller 70 inputs the boom operation command value Ibm to the corresponding proportional valve 20 (first boom proportional valve 20a or second boom proportional valve 20b), causing a pilot pressure corresponding to the boom operation command value Ibm to be output from the proportional valve 20, and the boom 6 operates at a speed corresponding to the boom operation command value Ibm. Likewise, the controller 70 inputs the bucket operation command value Ibk to the corresponding proportional valve 20 (first bucket proportional valve 20e or second bucket proportional valve 20f), causing a pilot pressure corresponding to the bucket operation command value Ibk to be output from the proportional valve 20, and the bucket 8 operates at a speed corresponding to the bucket operation command value Ibk.

[0081] Next, the case where the arm operation amount La is less than or equal to the second threshold Lth2 will be described. In the automatic control described above, when the arm operation amount La becomes less than or equal to the second threshold Lth2, the controller 70 stores the arm target speed Vatgt at the time when the arm operation amount La becomes less than or equal to the second threshold Lth2. Furthermore, when the arm operation amount La becomes less than or equal to the second threshold Lth2, the controller 70 calculates the arm target speed Vatgt so that it gradually decreases based on predetermined conditions. Specifically, the controller 70 uses the arm target speed Vatgt at the time when the arm operation amount La becomes less than or equal to the second threshold Lth2 as a reference and decreases the arm target speed Vatgt toward zero in proportion to the elapsed time t. As a result, when the arm operation amount La becomes less than or equal to the second threshold Lth2, the arm target speed Vatgt gradually decreases toward zero. The controller 70 may gradually decrease the arm target speed Vatgt by, for example, a rate limiter. A rate limiter is a process that suppresses the amount of change (decrease) in the target arm velocity Vatgt per unit time to a set value (or below the set value). In this case, the predetermined condition is the condition that the amount of change (decrease) in the target arm velocity Vatgt per unit time is suppressed to a set value (or below the set value).

[0082] Furthermore, the controller 70 may geometrically calculate the boom operation command value Ibm and the bucket operation command value Ibk based on the arm target speed Vatgt, which gradually decreases based on the predetermined conditions. The geometric calculation method is as described above. As a result, the boom speed Vbm and the bucket speed Vbk gradually decrease.

[0083] Furthermore, the controller 70 continuously determines whether the arm speed Va or target speed Vatgt of arm 7 has fallen below a predetermined speed threshold Vth. The speed threshold Vth is set to a value that indicates arm 7 is stopped. If the arm manipulation amount La is greater than the second threshold Lth2, the arm speed Va and target speed Vatgt will generally be higher than the speed threshold Vth. In this case, the controller 70 continues to perform automatic control.

[0084] On the other hand, when the arm operation amount La falls below the second threshold Lth2, the target speed Vatgt decreases according to the elapsed time t, so that the arm speed Va and the arm target speed Vatgt fall below the speed threshold Vth at a certain point. The controller 70 cancels automatic control on the condition that the arm speed Va or the arm target speed Vatgt is below the speed threshold Vth. Furthermore, the controller 70 sets the boom operation command value Ibm and the bucket operation command value Ibk to zero and stops the work device 4.

[0085] As described above, when the boom operation command value Ibm and bucket operation command value Ibk are calculated based on the arm operation amount La, if the automatic control is released the moment the arm operation amount La becomes zero, it may not be possible to stop the work device 4 instantaneously due to the inertia of the boom 6, etc. As a result, the bucket 8 may dig into the target construction surface, potentially degrading the construction accuracy of the construction machine 1. In contrast, when the arm operation amount La falls below the second threshold Lth2 and it is determined that the operator intends to stop the work device 4, the arm target speed Vatgt gradually decreases, causing the boom speed Vbm and bucket speed Vbk to also gradually decrease. As a result, when the arm operation amount La becomes zero, the work device 4 can be stopped instantaneously, the bucket 8 will not dig into the target construction surface, and the construction accuracy of the construction machine 1 can be maintained.

[0086] Figure 4 is a flowchart illustrating the control operation when moving the bucket 8 to the target construction surface in this embodiment. The controller 70 repeatedly executes the processes shown in this flowchart while the construction machine 1 is in operation.

[0087] First, the target construction surface is set in advance by the target construction surface setting device 30 (step S100). Next, the controller 70 determines whether the MC switch 28 is switched to the ON position and whether the arm operation amount La is greater than the first threshold Lth1 (step S110). If at least one of the following is satisfied (NO in step S110), the controller 70 outputs a boom operation command value Ibm based on the boom operation amount Lbm of the boom operation member 19a. Similarly, the controller 70 outputs a bucket operation command value Ibk based on the bucket operation amount Lbk of the bucket operation member 19c (step S180). In this case, the controller 70 also outputs an arm operation command value Ia based on the arm operation amount La of the arm operation member 19b.

[0088] On the other hand, if the MC switch 28 is switched to the ON position and the arm operating amount La is greater than the first threshold Lth1 (YES in step S110), the controller 70 calculates the arm target velocity Vatgt using the above-described equation (3) (step S120).

[0089] Next, the controller 70 determines whether the arm operating amount La is greater than the second threshold Lth2 (step S130). If the arm operating amount La is greater than the second threshold Lth2 (YES in step S130), the controller 70 geometrically calculates the boom operation command value Ibm and the bucket operation command value Ibk based on the arm target speed Vatgt, as described above (step S150).

[0090] On the other hand, if the arm operating amount La is less than or equal to the second threshold Lth2 (NO in S130), the controller 70 uses the arm target speed Vatgt at the moment the arm operating amount La becomes less than or equal to the second threshold Lth2 as a reference and reduces the arm target speed Vatgt according to the elapsed time t (step S140). As a result, the arm target speed Vatgt gradually decreases according to the elapsed time t. Next, the controller 70 geometrically calculates the boom operation command value Ibm and the bucket operation command value Ibk based on the calculated arm target speed Vatgt (step S150). At this time, as the arm target speed Vatgt gradually decreases, the boom operation command value Ibm and the bucket operation command value Ibk gradually decrease toward zero. As a result, the boom speed Vbm and the bucket speed Vbk gradually decrease.

[0091] In step S150, when the boom operation command value Ibm and the bucket operation command value Ibk are calculated, the controller 70 determines whether the arm speed Va or the arm target speed Vatgt has become less than or equal to the speed threshold Vth (step S160). If the arm speed Va or the arm target speed Vatgt is higher than the speed threshold Vth (NO in step S160), the controller 70 returns to step S130 and continues to perform automatic control. As a result, automatic control continues to be performed until the arm speed Va or the arm target speed Vatgt becomes less than or equal to the speed threshold Vth, thereby maintaining the construction accuracy of the construction machine 1.

[0092] On the other hand, if the arm speed Va or the arm target speed Vatgt falls below the speed threshold Vth (YES in step S160), the controller 70 cancels the automatic control and sets the boom operation command value Ibm and the bucket operation command value Ibk to zero (step S170). This allows the work device 4 to be stopped without shock.

[0093] [Differentiation] In the above embodiment, the automatic control was switched on and off by the MC switch 28, but in addition, the automatic control may also be switched on and off by the emergency stop button. Specifically, when the emergency stop button is switched on while the automatic control is running, the automatic control may be released on the condition that the speed Va of the arm 7 or the arm target speed Vatgt is the speed threshold Vth1. In this case, the operation of switching the emergency stop button on is an example of the operation of switching the switching device of this disclosure from the on position to the off position.

[0094] In the above embodiment, the boom 6 and bucket 8 were automatically controlled based on the arm operation amount La of the arm 7. However, the arm 7 and bucket 8 may also be automatically controlled based on the boom operation amount Lbm of the boom 6. In this case, the controller 70 determines whether or not to release the automatic control based on the boom speed Vbm of the boom 6. Alternatively, the boom 6 and arm 7 may be automatically controlled based on the bucket operation amount Lbk of the bucket 8. In this case, the controller 70 determines whether or not to release the automatic control based on the bucket speed Vbk of the bucket 8.

[0095] In the above embodiment, P control using equations (1) and (2) was exemplified as the feedback control in the first control example, but the feedback control may also be PI control, PD control, or PID control.

[0096] In the above embodiment, the specific part is an arm, but the specific part may be, for example, a boom.

[0097] In the above embodiment, the construction machine control device is provided on the construction machine 1, but the construction machine control device in this disclosure does not necessarily have to be provided on the construction machine and may be located at a location away from the construction machine. In this case, the construction machine control device and the construction machine are configured to be able to send and receive information via a network such as the Internet or a mobile phone network. [Explanation of Symbols]

[0098] 1: Construction machinery 4: Work equipment 6: Boom 7: Arm 8: Bucket 19: Operating component 28: Machine control switch (switching device) 70: Controller

Claims

1. A construction machine control device for a construction machine comprising a working device including a boom, an arm rotatably connected to the tip of the boom, and a tip attachment rotatably connected to the tip of the arm, The device includes a controller that performs automatic control of the work device for moving the aforementioned tip attachment toward a preset target construction surface. The controller is a construction machinery control device that continues the automatic control until the speed of a specific part of the work device, or a specific value correlated with this speed, falls below a specific threshold, which is a threshold for determining when the operation of the work device should stop.

2. The arm is equipped with an arm operating member that receives arm operation by an operator for moving the aforementioned arm, The specified portion is the arm, and the specified value is the speed of the arm or an arm-specific value which is a value correlated with this speed. The controller is configured to control the movement of the arm, the boom, and the tip attachment in the automatic control based on the arm operation. The construction machinery control device according to claim 1, wherein the controller terminates the automatic control when the arm specific value falls below the specific threshold.

3. The construction machine control device according to claim 2, wherein the controller calculates an arm operation command value, which is a command value for moving the arm, based on the amount of arm operation, and calculates a boom operation command value, which is a command value for moving the boom, such that the speed of the boom decreases as the height deviation, which is the deviation between the height of the target construction surface and the height of the tip attachment, decreases.

4. The arm operating member further comprises an arm operating member that receives arm operation by an operator for moving the aforementioned arm, The specified portion is the arm, and the specified value is the speed of the arm or a value correlated with this speed, which is the arm specified value, or the target value of the arm speed or a value correlated with this target value, The controller executes the automatic control when the amount of arm operation is greater than a predetermined first operation threshold. In the automatic control, the controller calculates the arm target value based on the amount of arm operation, and calculates the boom speed target value or a boom target value which is a value correlated with this target value based on the amount of arm operation or the arm target value. The controller, in the automatic control, calculates the arm target value such that when the amount of arm operation falls below a second operation amount threshold which is smaller than a first operation amount threshold, the arm target value gradually decreases based on predetermined conditions, and terminates the automatic control when the specific arm value or the arm target value falls below the specific threshold.

5. The aforementioned work apparatus, A construction machine comprising a construction machine control device according to any one of claims 1 to 4.

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