Construction machine and method for controlling construction machine

Abstract

A construction machine is provided with a vehicle body, a work machine, an actuator, and a controller. The work machine is movably supported with respect to the vehicle body. And the actuator is connected with the working device. The actuator operates the work machine. The controller performs automatic control of controlling the actuator so that the height of the work device in the gravitational direction is maintained even if the posture of the vehicle body changes. The controller determines whether or not the construction machine is in a non-working state in which the work by the work machine is not performed. And under the condition that the engineering machinery is in a non-working state, the controller stops automatic control.

Description

Technical Field

[0001] The present invention relates to an engineering machine and a method for controlling the engineering machine. Background Art

[0002] The construction machinery includes a body, a working device, and an actuator. The actuator is, for example, a hydraulic cylinder. The actuator is driven according to the operation of the driver to move the working device. For example, a motor grader includes a scraper as a working device. The motor grader includes a tandem drive and a frame as a body. The scraper is supported on the frame. The frame supports the front wheel so that it can rotate. The tandem drive supports the rear wheel. The driver moves the scraper up and down by operating the operating lever of the working device.

[0003] In the above-mentioned motor grader, when the front wheel passes over the undulation, the posture of the frame changes, and thus the height of the scraper changes. Patent document 1 discloses a technology for dealing with this problem. In patent document 1, a controller calculates the change in the height of the scraper according to the relative rotation angle between the frame and the tandem drive. The controller moves the scraper up and down according to the change in the height of the scraper. In this way, the scraper is kept at a specified height.

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: (Japanese) Patent Publication No. 2001-193095 Summary of the invention

[0007] Problems to be solved by the invention

[0008] However, in the motor grader of Patent Document 1, when the posture of the entire body including the tandem drive changes, the height direction of the scraper relative to the body also changes. For example, when the tandem drive is tilted from the horizontal plane, the height of the scraper calculated by the controller adopts a value different from the actual height of the scraper. Therefore, it is difficult to keep the scraper at a predetermined height relative to the ground with high precision. The purpose of the present disclosure is to keep the working device at a target height with high precision even when the construction machine is traveling on a undulating ground.

[0009] Technical solutions to solve problems

[0010] One method of the present disclosure provides a construction machine comprising a vehicle body, a working device, an actuator, and a controller. The working device is supported in a manner capable of moving relative to the vehicle body. The actuator is connected to the working device. The actuator moves the working device. The controller performs automatic control of the actuator so that the height of the working device in the direction of gravity is maintained even if the posture of the vehicle body changes. The controller determines whether the construction machine is in a non-operating state where no operation using the working device is being performed. When the construction machine is in a non-operating state, the controller stops the automatic control.

[0011] Another aspect of the present disclosure provides a method for controlling a construction machine, wherein the construction machine includes a vehicle body, a working device, and an actuator. The working device is supported so as to be movable relative to the vehicle body. The actuator is connected to the working device. The actuator causes the working device to move. The method includes: performing automatic control of the actuator so that the height of the working device in the direction of gravity is maintained even if the posture of the vehicle body changes; determining whether the construction machine is in a non-operating state where no operation using the working device is performed; and stopping automatic control when the construction machine is in a non-operating state.

[0012] Effects of the Invention

[0013] According to the present disclosure, even if the posture of the vehicle body changes, the height of the working device in the direction of gravity can be maintained by automatic control. Therefore, even when the construction machine is traveling on an undulating ground, the height of the working device is maintained with high precision. In addition, when the construction machine is in a non-operating state where no operation using the working device is being performed, the automatic control is stopped. Thus, it is possible to suppress the construction machine from performing unintentional actions when it is not operating. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a side view of the construction machine according to the embodiment.

[0015] Figure 2 It is a perspective view of the front part of the construction machinery.

[0016] Figure 3 It is a schematic diagram showing the drive system and control system of construction machinery.

[0017] Figure 4 It is a schematic rear view of the construction machine showing the posture of the working equipment.

[0018] Figure 5 It is a schematic plan view of the construction machine showing the posture of the working device.

[0019] Figure 6 It is a schematic enlarged side view of the construction machine showing the posture of the working device.

[0020] Figure 7 It is a schematic plan view of the construction machine showing the posture of the working device.

[0021] Figure 8 It is a schematic plan view of the construction machine showing the posture of the working device.

[0022] Fig. 9 It is a schematic side view showing a body coordinate system of the construction machine.

[0023] Fig.10 It is a schematic rear view showing a body coordinate system of the construction machine.

[0024] Fig.11 This is a flowchart showing the process of automatic control of the working machine.

[0025] Fig.12 It is a schematic side view showing a body coordinate system of the construction machine.

[0026] Fig.13 This is a flowchart showing the process of limiting automatic control.

[0027] Fig.14A It is a front view schematically showing the structure of the construction machine.

[0028] Fig. 14B It is a front view schematically showing the structure of the construction machine. DETAILED DESCRIPTION

[0029] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. Figure 1 It is a side view of the construction machine 1 according to the embodiment. Figure 2 2 is a perspective view of the front part of the construction machine 1. The construction machine 1 of this embodiment is a grader. Figure 1 As shown, the construction machine 1 includes a vehicle body 2 and a working device 3. The working device 3 is supported so as to be able to move relative to the vehicle body 2. The vehicle body 2 includes a vehicle frame 4, a tandem drive 5, front wheels 6, and rear wheels 7A and 7B.

[0030] The vehicle frame 4 supports the front wheel 6 and the working device 3. The vehicle frame 4 includes a front frame 11 and a rear frame 12. The rear frame 12 is connected to the front frame 11. The front frame 11 can be hinged to the left and right relative to the rear frame 12. It should be noted that in the following description, the front, rear, left and right directions refer to the front, rear, left and right directions of the vehicle body 2 when the hinge angle is 0, that is, the front frame 11 and the rear frame 12 are straight.

[0031] A cab 13 and a power room 14 are arranged on the rear frame 12. A driver's seat (not shown) is arranged in the cab 13. A drive system described later is arranged in the power room 14. The front frame 11 extends forward from the rear frame 12. The front wheel 6 is mounted on the front frame 11.

[0032] The tandem drive 5 is connected to the rear frame 12. The tandem drive 5 supports the rear wheels 7A and 7B and drives the rear wheels 7A and 7B. The tandem drive 5 includes a rear axle 10 extending in the left-right direction. The tandem drive 5 supports the rear frame 12 of the vehicle frame 4 so that it can swing around the rear axle 10. When the front wheel 6 moves up and down due to the ups and downs of the road surface that has not been leveled by the working device 3, the vehicle frame 4 swings around the rear axle 10 (see Fig. 9 ).

[0033] The rear wheels 7A and 7B include a pair of first rear wheels 7A and a pair of second rear wheels 7B. Figure 1 In the figure, only the left first rear wheel 7A and the left second rear wheel 7B are shown. The second rear wheel 7B is arranged behind the first rear wheel 7A. The rear axle 10 is arranged between the first rear wheel 7A and the second rear wheel 7B. The rear axle 10 becomes the swing center of the frame 4 relative to the tandem drive 5.

[0034] The working device 3 is movably connected to the vehicle body 2. The working device 3 includes a support member 15 and a scraper 16. The support member 15 is movably connected to the vehicle body 2. The support member 15 supports the scraper 16. The support member 15 includes a traction bar 17 and a turntable 18. The traction bar 17 and the turntable 18 are arranged below the front frame 11.

[0035] like Figure 2 As shown, the traction bar 17 is connected to the shaft support portion 19 of the front frame 11. The shaft support portion 19 is arranged at the front part of the front frame 11. The traction bar 17 extends from the front part of the front frame 11 to the rear. The traction bar 17 is supported relative to the front frame 11 so as to be able to swing at least in the up-down direction and the left-right direction of the vehicle body 2. For example, the shaft support portion 19 includes a ball joint. The traction bar 17 is rotatably connected to the front frame 11 via the ball joint.

[0036] The rotating disk 18 is connected to the rear part of the traction bar 17. The rotating disk 18 is supported rotatably with respect to the traction bar 17. The scraper 16 is connected to the rotating disk 18. The scraper 16 is supported on the traction bar 17 via the rotating disk 18. The scraper 16 is supported on the rotating disk 18 so as to be rotatable around the tilting shaft 21. The tilting shaft 21 extends in the left-right direction. The scraper 16 is supported on the rotating disk 18 so as to be slidable in the left-right direction.

[0037] The construction machine 1 includes a plurality of actuators 22-27 for changing the posture of the working device 3. The plurality of actuators 22-27 include a plurality of hydraulic cylinders 22-26. The plurality of hydraulic cylinders 22-26 are connected to the working device 3. The plurality of hydraulic cylinders 22-26 are extended and retracted by hydraulic pressure. The plurality of hydraulic cylinders 22-26 change the posture of the working device 3 relative to the vehicle body 2 by extending and retracting. In the following description, the extension and retraction of the hydraulic cylinders is referred to as "stroke action".

[0038] In detail, the plurality of hydraulic cylinders 22-26 include a left lift cylinder 22, a right lift cylinder 23, a traction rod moving cylinder 24, a blade tilting cylinder 25, and a blade moving cylinder 26. The left lift cylinder 22 and the right lift cylinder 23 are arranged to be separated from each other in the left-right direction. The left lift cylinder 22 is connected to the left portion of the traction rod 17. The right lift cylinder 23 is connected to the right portion of the traction rod 17. The left lift cylinder 22 and the right lift cylinder 23 are connected to the traction rod 17 so as to be able to swing left and right.

[0039] The left lift cylinder 22 and the right lift cylinder 23 are connected to the front frame 11 so as to be able to swing left and right. Specifically, the left lift cylinder 22 and the right lift cylinder 23 are connected to the front frame 11 via a lifter bracket 29. The lifter bracket 29 is connected to the front frame 11. The lifter bracket 29 supports the left lift cylinder 22 and the right lift cylinder 23 so as to be able to swing left and right. By the stroke action of the left lift cylinder 22 and the right lift cylinder 23, the traction rod 17 swings up and down around the shaft support portion 19. As a result, the scraper 16 moves up and down.

[0040] The drawbar moving cylinder 24 is connected to the drawbar 17 and the front frame 11. The drawbar moving cylinder 24 is connected to the front frame 11 via the lifter bracket 29. The drawbar moving cylinder 24 is connected to the front frame 11 so as to be swingable. The drawbar moving cylinder 24 is connected to the drawbar 17 so as to be swingable. The drawbar moving cylinder 24 extends obliquely downward from the front frame 11 toward the drawbar 17. The drawbar moving cylinder 24 extends from one side of the left and right sides of the front frame 11 toward the opposite side. The drawbar 17 is swung left and right around the shaft support 19 by the stroke action of the drawbar moving cylinder 24.

[0041] like Figure 1 As shown, the scraper tilt cylinder 25 is connected to the rotary table 18 and the scraper 16. Through the stroke action of the scraper tilt cylinder 25, the scraper 16 rotates around the tilt axis 21. Figure 2 As shown, the scraper moving cylinder 26 is connected to the rotating disk 18 and the scraper 16. Through the stroke action of the scraper moving cylinder 26, the scraper 16 slides left and right relative to the rotating disk 18.

[0042] The plurality of actuators 22 to 27 include a rotary actuator 27. The rotary actuator 27 is connected to the drawbar 17 and the rotary disk 18. The rotary actuator 27 rotates the rotary disk 18 relative to the drawbar 17. Thus, the scraper 16 rotates around a rotation axis extending in the vertical direction.

[0043] Figure 3 Schematic diagram showing a drive system 8 and a control system 9 of an engineering machine 1. Figure 3 As shown, the construction machine 1 includes a driving source 31, a hydraulic pump 32, a power transmission device 33, and a control valve 34. The driving source 31 is, for example, an internal combustion engine. Alternatively, the driving source 31 may be an electric motor, or a combination of an internal combustion engine and an electric motor. The hydraulic pump 32 is driven by the driving source 31 to eject working oil.

[0044] The control valve 34 is connected to the hydraulic pump 32 and the plurality of hydraulic cylinders 22 to 26 via a hydraulic circuit. The control valve 34 includes a plurality of valves connected to the plurality of hydraulic cylinders 22 to 26, respectively. The control valve 34 controls the flow rate of the hydraulic oil supplied from the hydraulic pump 32 to the plurality of hydraulic cylinders 22 to 26.

[0045] In this embodiment, the swing actuator 27 is a hydraulic motor. The control valve 34 is connected to the hydraulic pump 32 and the swing actuator 27 via a hydraulic circuit. The control valve 34 controls the flow rate of the hydraulic oil supplied from the hydraulic pump 32 to the swing actuator 27. It should be noted that the swing actuator 27 may also be an electric motor.

[0046] The power transmission device 33 transmits the driving force from the driving source 31 to the rear wheels 7A, 7B. The power transmission device 33 may also include a torque converter and / or a plurality of speed gears. Alternatively, the power transmission device 33 may also be a gearbox such as HST (Hydraulic Static Transmission) or HMT (Hydraulic Mechanical Transmission). The construction machine 1 is provided with a shift operating component 47. The shift operating component 47 can be operated to a neutral position N, a forward position F, and a reverse position R. The power transmission device 33 switches the driving mode to forward, reverse, and neutral according to the operating position of the shift operating component 47.

[0047] like Figure 3 As shown, the construction machine 1 includes an operating device 35 and a controller 36. The operating device 35 can be operated by the driver to change the posture of the working device 3. The posture of the working device 3 indicates the position and orientation of the scraper 16 relative to the vehicle body 2. Figure 4 2 is a schematic rear view of the construction machine 1 showing the posture of the working device 3. Figure 4As shown, according to the operation of the operating device 35, the height of the left end portion 161 and the height of the right end portion 162 of the scraper 16 are changed.

[0048] According to the operation of the operating device 35 , the yaw angle θ1 , the pitch angle θ2 , and the roll angle θ3 of the drawbar 17 are changed. Figure 5 FIG. 1 is a schematic top view of the construction machine 1 showing the posture of the working device 3. Figure 5 As shown in FIG. 1 , the yaw angle θ1 of the drawbar 17 is an inclination angle of the left-right direction of the drawbar 17 relative to the front-rear direction of the vehicle body 2. It should be noted that the yaw angle θ1 of the drawbar 17 may also be an inclination angle of the left-right direction of the drawbar 17 relative to the front-rear direction of the front frame 11. The position of the scraper 16 in the left-right direction changes according to the yaw angle θ1 of the drawbar 17.

[0049] Figure 6 3 is a schematic side view of the construction machine 1 showing the posture of the working device 3. Figure 6 As shown in FIG. 1 , the pitch angle θ2 of the traction bar 17 is the inclination angle of the traction bar 17 in the vertical direction relative to the front-rear direction of the vehicle body 2. Figure 4 As shown, the roll angle θ3 of the drawbar 17 is an inclination angle of the drawbar 17 about a roll axis A1 extending in the front-rear direction of the vehicle body 2 .

[0050] In addition, according to the operation of the operating device 35 , the rotation angle θ4 of the rotary disk 18 , the inclination angle θ5 of the scraper 16 , and the movement amount W1 of the scraper 16 are changed. Figure 7 FIG. 1 is a schematic top view of the construction machine 1 showing the posture of the working device 3. Figure 7 As shown in FIG. 1 , the rotation angle θ4 of the turntable 18 is the rotation angle θ4 of the turntable 18 relative to the front-rear direction of the vehicle body 2. Figure 6 As shown, the inclination angle θ5 of the scraper 16 is an inclination angle of the scraper 16 about an inclination axis 21 extending in the left-right direction. Figure 8 FIG. 1 is a schematic top view of the construction machine 1 showing the posture of the working device 3. Figure 8 As shown, the movement amount W1 of the scraper 16 is the sliding amount of the scraper 16 in the left-right direction relative to the rotating disk 18 .

[0051] The operating device 35 includes a plurality of operating components 41 to 46 . The plurality of operating components 41 to 46 are provided corresponding to the left lift cylinder 22 , the right lift cylinder 23 , the drawbar movement cylinder 24 , the blade tilt cylinder 25 , the blade movement cylinder 26 , and the rotation actuator 27 , respectively.

[0052] The plurality of operating members 41-46 include a left lift rod 41, a right lift rod 42, a traction rod moving rod 43, a rotation rod 44, a blade tilting rod 45, and a blade moving rod 46. The left lift cylinder 22 is extended and retracted according to the operation of the left lift rod 41. The right lift cylinder 23 is extended and retracted according to the operation of the right lift rod 42.

[0053] The drawbar moving cylinder 24 is extended and retracted according to the operation of the drawbar moving lever 43. The rotary actuator 27 is rotated according to the operation of the rotary lever 44. The blade tilting cylinder 25 is extended and retracted according to the operation of the blade tilting lever 45. The blade moving cylinder 26 is extended and retracted according to the operation of the blade moving lever 46. The plurality of operating members 41-46 respectively output signals indicating the operation of each operating member 41-46 by the driver.

[0054] The controller 36 drives the construction machine 1 by controlling the driving source 31 and the power transmission device 33. In addition, the controller 36 operates the working device 3 by controlling the hydraulic pump 32 and the control valve 34. The controller 36 includes a processor 37 and a storage device 38. The processor 37 is, for example, a CPU, and executes a program for controlling the construction machine 1. The storage device 38 includes a memory such as a RAM and a ROM, and an auxiliary storage device such as an SSD or a HDD. The storage device 38 stores a program and data for controlling the construction machine 1.

[0055] like Figure 3 As shown, the construction machine 1 includes a working device sensor 48 for detecting the posture of the above-mentioned working device 3. The working device sensor 48 includes a plurality of sensors S1-S8. The plurality of sensors S1-S8 are, for example, magnetic sensors. However, the plurality of sensors S1-S8 may also be other types of sensors such as optical sensors. The plurality of sensors S1-S5 detect the stroke length of the above-mentioned plurality of hydraulic cylinders 22-26. The plurality of sensors S1-S5 include a left lifting sensor S1, a right lifting sensor S2, a traction bar movement sensor S3, a scraper tilt sensor S4, and a scraper movement sensor S5.

[0056] The left lift sensor S1 detects the stroke length of the left lift cylinder 22. The right lift sensor S2 detects the stroke length of the right lift cylinder 23. The drawbar movement sensor S3 detects the stroke length of the drawbar movement cylinder 24. The blade tilt sensor S4 detects the stroke length of the blade tilt cylinder 25. The blade movement sensor S5 detects the stroke length of the blade movement cylinder 26.

[0057] The plurality of sensors S1-S8 include a rotation sensor S6. The rotation sensor S6 detects the rotation angle θ4 of the turntable 18. The plurality of sensors S1-S8 output signals indicating the detected stroke length and the rotation angle θ4. The plurality of sensors S1-8 include a left cylinder angle sensor S7 and a right cylinder angle sensor S8. The left cylinder angle sensor S7 detects the swing angle of the left lift cylinder 22 in the left-right direction relative to the lifter bracket 29. The right cylinder angle sensor S8 detects the swing angle of the right lift cylinder 23 in the left-right direction relative to the lifter bracket 29. Using these sensors S1-S8, the posture of the drawbar 17 relative to the vehicle body 2 is detected, and the posture of the scraper 16 relative to the drawbar 17 is detected. That is, using these sensors S1-S8, the posture of the scraper 16 relative to the vehicle body 2 is detected.

[0058] The construction machine 1 includes a body sensor 49 and a vehicle speed sensor 50. The vehicle speed sensor 50 detects the vehicle speed of the construction machine 1. The body sensor 49 is, for example, an IMU (inertial measurement unit). The body sensor 49 detects body posture data indicating the posture of the body 2. The body posture data includes the pitch angle and the roll angle of the body 2. It should be noted that the body sensor 49 is not limited to the IMU. The body sensor 49 can be any unit that measures the pitch angle and the roll angle of the body 2, for example, it can also be an inclinometer.

[0059] The vehicle body sensor 49 is mounted on the vehicle frame 4. Therefore, if Fig. 9 As shown in FIG. 1 , the pitch angle θ6 of the vehicle body 2 is the inclination angle of the vertical direction of the frame 4 relative to the horizontal direction. Fig.10 As shown, the roll angle θ7 of the vehicle body 2 is the inclination angle of the left-right direction of the vehicle frame 4 relative to the horizontal direction. It should be noted that the vehicle body sensor 49 is not limited to being installed on the vehicle frame 4, and can also be installed at other locations of the vehicle body 2 whose relative position relative to the vehicle frame 4 does not change. For example, the vehicle body sensor 49 can also be arranged at other locations other than the location where the relative position of the tandem drive 5 and the traction rod 17 relative to the vehicle frame 4 changes.

[0060] The controller 36 acquires the work device posture data indicating the posture of the work device 3 relative to the vehicle body 2 based on the signal from the work device sensor 48. The work device posture data includes the height of the left end 161 and the height of the right end 162 of the scraper 16, the yaw angle θ1, the pitch angle θ2, the roll angle θ3 of the drawbar 17, the rotation angle θ4 of the turntable 18, the inclination angle θ5 of the scraper 16, and the movement amount W1 of the scraper 16. The controller 36 acquires the vehicle body posture data based on the signal from the vehicle body sensor 49. The controller 36 changes the posture of the work device 3 by controlling the plurality of actuators 22-27 according to the operation of the plurality of operating members 41-46.

[0061] In addition, the controller 36 performs automatic control of the working device 3 based on the vehicle body posture data and the working device posture data. In the automatic control of the working device 3, the controller 36 controls the left lift cylinder 22 and the right lift cylinder 23 to keep the working device 3 at the target height. The processing of the automatic control of the working device 3 is described below. Fig.11 This is a flowchart showing the process of automatic control of the working machine 3 .

[0062] like Fig.11 As shown, in step S101, the controller 36 determines whether the operating device 35 is operated. When there is no operation input of the operating device 35 for a certain period of time, the controller 36 may also determine that the operating device 35 is not operated. When at least one of the above-mentioned operating components 41-46 is operated, the controller 36 does not perform automatic control of the working device 3. Therefore, the controller 36 changes the posture of the working device 3 by controlling the multiple actuators 22-27 according to the operation of the multiple operating components 41-46. When the operating components 41-46 are not operated, the process enters step S102.

[0063] In step S102, the controller 36 acquires the current posture of the vehicle body 2. Here, the controller 36 acquires the current posture of the vehicle body 2 based on the vehicle body posture data. In step S103, the controller 36 acquires the current posture of the working device 3. Here, the controller 36 acquires the current posture of the working device 3 based on the working device posture data.

[0064] In step S104, the controller 36 calculates the current height of the working device 3. The controller 36 calculates the height of the working device 3 based on the vehicle body posture data and the working device posture data. For example, the height of the working device 3 is the height of the left end 161 and the height of the right end 162 of the scraper 16. Here, the height of the working device 3 is the height of the left end 161 and the height of the right end 162 of the scraper 16. Fig.12 The origin O1 of the vehicle body 2 is shown as a reference point, and the height in the gravity direction from the origin O1 is shown as follows. For example, the height of the working device 3 refers to the height of the working device 3 in the gravity direction from a horizontal plane including the origin O1 of the vehicle body 2.

[0065] like Fig.12 As shown, when the construction machine 1 is moving forward to perform work, the origin O1 of the vehicle body 2 is arranged on the tandem drive 5. For example, the origin O1 of the vehicle body 2 is arranged at the center in the left-right direction of the rear axle 10. Fig.12 In FIG. 1 , the Z1 axis represents the direction of gravity. The X1 axis represents the front-rear direction of the vehicle body 2 which is perpendicular to the direction of gravity. Figure 4 In FIG. 1 , the Y1 axis represents the left-right direction of the vehicle body 2 perpendicular to the gravity direction. The posture of the vehicle body 2 changes with the origin O1 of the vehicle body 2 as the center. For example, Fig. 9As shown in FIG. 1 , the pitch angle θ6 of the vehicle body 2 changes with the origin O1 as the center. Fig.10 As shown, the roll angle θ7 of the vehicle body 2 changes around the origin O1.

[0066] In step S105, the controller 36 determines the target posture of the work device 3. The controller 36 calculates the target posture of the work device 3 so that the height of the work device 3 becomes the target height. It should be noted that the controller 36 stores the height of the work device 3 when it is determined that the operation of the operating device 35 is not performed as the target height. For example, the controller 36 calculates the target pitch angle and target roll angle of the traction bar 17 so that the height of the work device 3 becomes the target height.

[0067] In step S106, the controller 36 controls at least one of the actuators 22-27 so that the height of the working device 3 becomes the target height. For example, the controller 36 controls the lift cylinders 22, 23 and the drawbar moving cylinder 24 so that the pitch angle θ2 of the drawbar 17 becomes the target pitch angle, and the roll angle θ3 of the drawbar 17 becomes the target roll angle.

[0068] In this case, the controller 36 controls the lifting cylinders 22 and 23 and the drawbar moving cylinder 24 so that the left-right position of the scraper 16 does not change. That is, in the construction machine 1, not only the height direction of the scraper 16 but also the left-right position of the scraper 16 changes due to the extension and retraction of the lifting cylinders 22 and 23. Therefore, the controller 36 controls the drawbar moving cylinder 24 so that the change in the left-right position of the scraper 16 caused by the extension and retraction of the lifting cylinders 22 and 23 is offset. In this way, the height of the working device 3 is maintained at the target height, and the left-right position of the working device 3 is maintained.

[0069] The controller 36 controls the actuators 22 to 27 by repeatedly performing the above-described processing of steps S102 to S106 so as to keep the working machine 3 at the target height. When the controller 36 operates the operating device 35 during the automatic control, the automatic control is terminated (step S101 ).

[0070] According to the construction machine 1 of the present embodiment described above, the working device 3 is maintained at the target height of the working device 3 by automatic control. The target height is the height in the gravity direction from the origin O1 of the vehicle body 2, and the working device 3 is maintained at the target height of the working device 3 even if the posture of the vehicle body 2 changes. Therefore, even when the construction machine 1 travels on a undulating ground, the working device 3 is maintained at the target height with high accuracy.

[0071] For example, in Fig. 9 In FIG. 1 , the scraper 16′ indicated by the dotted line indicates the position of the scraper 16 when the automatic control is not performed. Fig. 9As shown, without automatic control, when the front wheel 6 rises and falls, the scraper 16' will also Fig.12 However, in the construction machine 1 of the present embodiment, as shown in FIG. Fig. 9 As shown, the scraper 16 is automatically controlled to maintain the target height of the working device 3 in the gravity direction. Therefore, even if the front wheel 6 rises and falls, the scraper 16 is accurately maintained at the target height by controlling the actuators 22-27 by the controller 36.

[0072] Next, the process of limiting the automatic control will be described. Fig.13 is a flowchart showing the process of limiting automatic control. When automatic control is effective, the controller 36 executes Fig.13 The process shown in the figure determines whether to limit the automatic control. Fig.13 As shown, in step S201, the controller 36 determines whether the construction machine 1 is in a non-operating state. The non-operating state means a state in which the construction machine 1 is not performing work using the working device 3.

[0073] The controller 36 determines whether the construction machine 1 is in a non-operating state based on the driving mode of the vehicle body 2. Specifically, when the driving mode is switched from forward to neutral, or from neutral to reverse, the controller 36 determines that the construction machine 1 is in a non-operating state. Switching the driving mode from forward to neutral, or from neutral to reverse means that the construction machine 1 stops or reverses. In this case, the construction machine 1 is not performing work using the working device 3, so the controller 36 determines that the construction machine 1 is in a non-operating state.

[0074] For example, when the shift operating member 47 is switched from the forward position F to the neutral position N, the controller 36 determines that the construction machine 1 is not in operation. When the shift operating member 47 is switched from the neutral position N to the reverse position R, the controller 36 determines that the construction machine 1 is not in operation.

[0075] In addition, the controller 36 determines whether the construction machine 1 is in a non-operating state based on the position of the work implement 3. Specifically, when the stroke length of the left lift cylinder 22 is less than the length threshold and the stroke length of the right lift cylinder 23 is less than the length threshold, the controller 36 determines that the construction machine 1 is in a non-operating state.

[0076] For example, Fig.14A and Fig. 14B 1 is a front view schematically showing the structure of the construction machine 1. Fig.14A In , the stroke length L1 of the left lift cylinder 22 is greater than the first length threshold, and the stroke length L2 of the right lift cylinder 23 is greater than the first length threshold. Fig. 14B, the stroke length L1 of the left lift cylinder 22 is less than the first length threshold, and the stroke length L2 of the right lift cylinder 23 is less than the first length threshold.

[0077] like Fig.14A As shown, when the stroke length L1 of the left lift cylinder 22 is greater than the first length threshold and the stroke length L2 of the right lift cylinder 23 is greater than the first length threshold, the scraper 16 is at the first height position. The first height position is the position of the scraper 16 when the construction machine 1 performs work using the working device 3.

[0078] like Fig. 14B As shown, when the stroke length L1 of the left lift cylinder 22 is less than the first length threshold and the stroke length L2 of the right lift cylinder 23 is less than the first length threshold, the scraper 16 is located at the second height position. The second height position is the position of the scraper 16 when the construction machine 1 is traveling without performing work using the working device 3. The second height position is higher than the first height position.

[0079] As described above, when the scraper 16 is at the second height position, the construction machine 1 travels without performing work using the work device 3. Therefore, when the stroke length L1 of the left lift cylinder 22 is less than the first length threshold, and the stroke length L2 of the right lift cylinder 23 is less than the first length threshold, the controller 36 determines that the construction machine 1 is in a non-operating state. On the contrary, when the stroke length L1 of the left lift cylinder 22 is greater than the first length threshold, and the stroke length L2 of the right lift cylinder 23 is greater than the first length threshold, the controller 36 determines that the construction machine 1 is not in a non-operating state.

[0080] In addition, when the vehicle speed is greater than or equal to a predetermined first speed threshold, the controller 36 determines that the construction machine 1 is in a non-operating state. For example, the first speed threshold is set to a level that indicates that the construction machine 1 is traveling at a high speed. When the construction machine 1 is traveling at a high speed, the work using the work implement 3 is not performed. Therefore, when the vehicle speed is greater than or equal to a predetermined first speed threshold, the controller 36 determines that the construction machine 1 is in a non-operating state.

[0081] In step S201 , when it is determined that the construction machine 1 is not in operation, the process proceeds to step S202 . In step S202 , the controller 36 stops the automatic control. When the automatic control is stopped, the controller 36 controls the actuators 22 - 27 according to the manual operation of the operating device 35 .

[0082] It should be noted that, in step S201 , when the controller 36 determines that the construction machine 1 is not in the non-operating state, the automatic control is maintained. In other words, when the controller 36 determines that the construction machine 1 is in the operating state where the work implement 3 is performing the work, the automatic control is maintained.

[0083] After the automatic control is stopped in step S202, the process proceeds to step S203. In step S203, the controller 36 determines whether a predetermined recovery condition is satisfied. The recovery condition includes the driving mode switching from neutral to forward, or switching from reverse to neutral. For example, when the shift operating member 47 is switched from the neutral position N to the forward position F, the controller 36 determines that the recovery condition is satisfied. When the shift operating member 47 is switched from the reverse position R to the neutral position N, the controller 36 determines that the recovery condition is satisfied.

[0084] The restoration condition includes that the stroke length L1 of the left lift cylinder 22 is greater than the second length threshold, and the stroke length L2 of the right lift cylinder 23 is greater than the second length threshold. The second length threshold and the first length threshold may be the same or different. When the stroke length L1 of the left lift cylinder 22 is greater than the second length threshold, and the stroke length L2 of the right lift cylinder 23 is greater than the second length threshold, the controller 36 determines that the restoration condition is satisfied.

[0085] The restoration condition includes that the vehicle speed is less than a predetermined second speed threshold. The second speed threshold may be the same as or different from the first speed threshold. When the vehicle speed is less than the predetermined second speed threshold, the controller 36 determines that the restoration condition is satisfied.

[0086] If it is determined in step S203 that the restoration condition is satisfied, the process proceeds to step S204. It should be noted that if it is determined in step S203 that the restoration condition is not satisfied, the stop of the automatic control is maintained.

[0087] In step S204, the controller 36 resumes automatic control. When automatic control is resumed, the controller 36 restarts Fig.11 The process of automatic control is shown.

[0088] In the construction machine 1 of the present embodiment described above, when the construction machine 1 is in a non-operating state where no operation using the working device 3 is being performed, the automatic control is stopped. Thus, it is possible to suppress the construction machine 1 from performing unintentional movements when not performing an operation. For example, when the construction machine 1 is in a reversing operation, the automatic control is stopped. Thus, it is possible to suppress unintentional movements of the working device 3 during the reversing operation. In addition, when the construction machine 1 is traveling for transfer, the automatic control is stopped. Thus, unintentional movements of the working device 3 are suppressed during the travel for transfer.

[0089] As mentioned above, although one embodiment of the present disclosure has been described, the present disclosure is not limited to the above-mentioned embodiment, and various changes can be made within the scope not departing from the gist of the invention.

[0090] The construction machine 1 is not limited to a motor grader, but may be other construction machines 1 such as a bulldozer. In other construction machines 1 such as a bulldozer, the position of the origin O1 can be appropriately set according to the structural characteristics of the construction machine 1. The structure of the working device 3 is not limited to the structure of the above-mentioned embodiment, and may also be changed. For example, the working device 3 may also include a scraper 16 and a lifting arm. The lifting arm may also support the scraper 16 and be connected to the vehicle body. The parameters representing the posture of the working device 3 are not limited to the parameters of the above-mentioned embodiment, and may also be changed.

[0091] The plurality of operating components 41-46 are not limited to the components of the above-mentioned embodiment, and may be changed. For example, the operating component is not limited to a rod, and may be other components such as a joystick, a switch, or a touch panel. The plurality of operating components 41-46 may also be components that directly operate each of the actuators 22-27.

[0092] The sensor for detecting the posture of the working device 3 is not limited to the sensor of the above-mentioned embodiment, and can also be changed. The sensors S1-S5 are not limited to detecting the stroke length, and can also directly detect the angle. The working device sensor 48 can also include an IMU (inertial measurement unit). The IMU can also be installed on the traction rod 17. The posture of the traction rod 17 can also be detected by the IMU. Either the left cylinder angle sensor S7 or the right cylinder angle sensor S8 can also be omitted.

[0093] The operating device 35 may also include an operating component for automatic control. The controller 36 may also start the automatic control according to the operation of the operating component for automatic control. The controller 36 may also end the automatic control according to the operation of the operating component for automatic control. The controller 36 may also store the height of the working device 3 when the automatic control is started as the target height according to the operation of the operating component for automatic control.

[0094] In the above-mentioned automatic control, if the posture (angle) or posture change (angular velocity) of the vehicle body 2 exceeds a prescribed value, the detection error of the sensors S1-S8 may become larger. In addition, in the case of a sudden acceleration or deceleration exceeding a prescribed amount, the reaction speed of the sensors S1-S8 may not be able to keep up. In this case, the controller 36 may also temporarily release the automatic control. In the case where the difference between the target posture of the working device 3 and the current posture exceeds a prescribed threshold, the controller 36 may also temporarily release the automatic control.

[0095] In the above embodiment, the automatic control is described when the construction machine 1 moves forward and performs work, but the present invention can also be applied to the case where the construction machine 1 moves backward and performs work. In this case, the origin O of the vehicle body 2 may be the center position between the left and right front wheels 6.

[0096] In the above-mentioned embodiment, the controller 36 obtains the posture of the working device 3 when there is no operation of the operating device 35 for a certain period of time, and obtains the height of the working device 3 at this time as the current height of the working device 3. However, the method for obtaining the current height of the working device 3 is not limited to this, and can also be changed. For example, the controller 36 can also obtain the posture of the working device 3 when an operating device such as a button is operated, and obtain the height of the working device 3 at this time as the current height of the working device 3. A switch for increasing or decreasing the acquired height of the working device 3 by a specified amount can also be provided. The controller 36 can also change the target posture of the working device 3 according to the operation of the switch. In this way, the target posture of the working device 3 can be fine-tuned.

[0097] The process of limiting automatic control is not limited to the above process and can be changed. For example, the condition indicating the non-operating state is not limited to the above condition and can be changed. The recovery condition is not limited to the above condition and can be changed.

[0098] Industrial Applicability

[0099] According to the present disclosure, even when the construction machine is traveling on a rugged ground, the working device is kept at a target height with high accuracy. In addition, the construction machine can be prevented from performing unintentional movements when not working.

[0100] Description of Reference Numerals

[0101] 2: vehicle body, 3: working device, 22-27: actuator, 36: controller.

Claims

1. A construction machine, characterized in that: have: Car body; a working device movably supported relative to the vehicle body; an actuator connected to the working device to activate the working device; as well as Controller, As far as the controller is concerned, performing automatic control of the actuator so that the height of the working device in the direction of gravity is maintained even if the posture of the vehicle body changes, determining whether the construction machine is in a non-operating state where no operation using the working device is being performed, When the construction machine is in the non-operating state, the automatic control is stopped.

2. The construction machinery according to claim 1, characterized in that: There is also an operating device that can be manually operated by a driver to activate the working device. The controller controls the actuator according to a manual operation of the operating device when the automatic control is stopped.

3. The construction machine according to claim 1, characterized in that: The vehicle body can switch the driving mode to forward, reverse, and neutral. The controller determines whether the construction machine is in the non-operating state according to the travel mode of the vehicle body.

4. The construction machine according to claim 3, characterized in that: The controller stops the automatic control when the driving mode is switched from the forward driving mode to the neutral driving mode or from the neutral driving mode to the reverse driving mode.

5. The construction machine according to claim 1, characterized in that: The controller determines whether the construction machine is in the non-operating state according to the position of the working device.

6. The construction machine according to claim 5, characterized in that: The actuator includes a lift cylinder for moving the working device up and down. The controller stops the automatic control when the length of the lift cylinder is equal to or less than a predetermined length threshold.

7. The construction machine according to claim 1, characterized in that: The controller obtains the speed of the engineering machinery. When the vehicle speed is equal to or higher than a predetermined speed threshold, the automatic control is stopped.

8. The construction machine according to claim 1, characterized in that: After stopping the automatic control, the controller determines whether a prescribed recovery condition is met. When the restoration condition is met, the automatic control is restored.

9. A method for controlling a construction machine, characterized in that: The construction machine includes a vehicle body, a working device supported so as to be movable relative to the vehicle body, and an actuator connected to the working device and causing the working device to move. This method has: performing automatic control of the actuator so that the height of the working device in the direction of gravity is maintained even if the posture of the vehicle body changes; determining whether the construction machine is in a non-operating state where no operation using the working device is being performed; When the construction machine is in the non-operating state, the automatic control is stopped.

10. The method according to claim 9, characterized in that Also available: acquiring an operation signal indicating a manual operation from an operation device operable by a driver to cause the working device to operate; When the automatic control is stopped, the actuator is controlled according to a manual operation of the operating device.

11. The method according to claim 9, characterized in that The vehicle body can switch the driving mode to forward, reverse, and neutral. The method further comprises determining whether the construction machine is in the non-operating state based on the travel mode.

12. The method according to claim 11, characterized in that The controller stops the automatic control when the driving mode is switched from the forward driving mode to the neutral driving mode or from the neutral driving mode to the reverse driving mode.

13. The method according to claim 9, characterized in that have: Whether the construction machine is in the non-operating state is determined based on the position of the working device.

14. The method according to claim 13, characterized in that The actuator includes a lift cylinder for moving the working device up and down. The automatic control is stopped when the length of the lift cylinder is equal to or smaller than a predetermined length threshold.

15. The method according to claim 9, characterized in that have: Obtaining the speed of the engineering machinery; When the vehicle speed is equal to or higher than a predetermined speed threshold, the automatic control is stopped.

16. The method according to claim 9, characterized in that have: After stopping the automatic control, determining whether a prescribed recovery condition is met; When the restoration condition is met, the automatic control is restored.

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