Work machine and method for controlling work machine

Abstract

This work machine is provided with a vehicle body, a work machine, an actuator, a first operation device, and a controller. The work machine is movably supported with respect to the vehicle body. The actuator operates the work machine. The first operation device is operated to set a target height of the working machine in a gravity direction and a cross slope angle indicating an inclination angle of the working machine with respect to a horizontal plane. The controller acquires a target height of the work machine. The controller controls the actuator such that the height of the work machine in the gravitational direction is maintained at a target height even if the attitude of the vehicle body changes.

Description

Technical Field

[0001] The present disclosure relates to a work machine and a method for controlling a work machine. Background Art

[0002] The working machine includes a body, a working machine, and an actuator. The actuator is, for example, a hydraulic cylinder. The actuator is driven according to the operation of the operator, thereby causing the working machine to move. For example, a motor grader includes a bulldozer as a working machine. The motor grader includes a tandem drive and a frame as a body. The bulldozer is supported on the frame. The frame supports the front wheel rotatably. The tandem drive supports the rear wheel. The operator moves the bulldozer up and down by operating the lever of the working machine.

[0003] In the above-mentioned motor grader, when the front wheel passes over the undulation, the height of the bulldozer blade changes due to the change in the posture of the frame. Patent document 1 discloses a technology for coping with this problem. In patent document 1, a controller calculates the change in the height of the bulldozer blade based on the relative rotation angle between the frame and the tandem drive. The controller moves the bulldozer blade up and down based on the change in the height of the bulldozer blade. As a result, the bulldozer blade is maintained at a specified height.

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent Application 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 vehicle body including the tandem drive changes, the height direction of the bulldozer blade relative to the vehicle body also changes. For example, when the tandem drive tilts from the horizontal plane, the height of the bulldozer blade calculated by the controller takes a value different from the actual height of the bulldozer blade. Therefore, it is difficult to maintain the bulldozer blade at a predetermined height relative to the ground with high accuracy.

[0009] In addition, in a motor grader, work is sometimes performed with the bulldozer blade tilted relative to the horizontal plane. In this case, the inclination angle of the bulldozer blade relative to the horizontal plane as seen from the rear of the vehicle body (hereinafter referred to as the crossslope angle) is maintained constant. However, in the case where the posture of the entire vehicle body changes as described above, it is difficult to maintain a constant crossslope angle. The purpose of the present disclosure is to keep the working machine at a target height with high precision and maintain the crossslope angle of the working machine even when the working machine is traveling on undulating ground.

[0010] Means for solving problems

[0011] One embodiment of the present disclosure is a working machine, comprising a vehicle body, a working machine, an actuator, a first operating device, and a controller. The working machine is supported so as to be movable relative to the vehicle body. The actuator is connected to the working machine. The actuator causes the working machine to move. The first operating device is operated to set a target height of the working machine in the direction of gravity and a slope angle representing an inclination angle of the working machine relative to a horizontal plane. The controller obtains the target height of the working machine. The controller controls the actuator so that the height of the working machine in the direction of gravity is maintained at the target height even if the posture of the vehicle body changes.

[0012] The method involved in other embodiments of the present disclosure is a method for controlling a working machine. The working machine comprises: a vehicle body; a working machine; and an actuator. The working machine is supported so as to be movable relative to the vehicle body. The actuator is connected to the working machine. The actuator causes the working machine to move. The method comprises: setting a target height and a transverse slope angle of the working machine according to operation of a first operating device that is operated to set a target height of the working machine in a gravity direction and a transverse slope angle representing an inclination angle of the working machine relative to a horizontal plane; and controlling the actuator so that the height of the working machine in the gravity direction is maintained at the target height even if the posture of the vehicle body changes.

[0013] Effects of the Invention

[0014] According to the present disclosure, even if the posture of the vehicle body changes, the height and the slope angle of the working machine in the gravity direction are maintained. Therefore, even when the working machine travels on an undulating ground, the height and the slope angle of the working machine are maintained with high accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a side view of the working machine according to the embodiment.

[0016] Figure 2 It is a perspective view of the front part of the working machine.

[0017] Figure 3 It is a schematic diagram showing a drive system and a control system of a working machine.

[0018] Figure 4 It is a schematic rear view of the working machine showing the posture of the working machine.

[0019] Figure 5 It is a schematic plan view of the working machine showing the posture of the working machine.

[0020] Figure 6 It is a schematic enlarged side view of the working machine showing the posture of the working machine.

[0021] Figure 7 It is a schematic plan view of the working machine showing the posture of the working machine.

[0022] Figure 8 It is a schematic plan view of the working machine showing the posture of the working machine.

[0023] Fig. 9 It is a schematic side view showing a vehicle body coordinate system of the working machine.

[0024] Fig.10 It is a schematic rear view showing a vehicle body coordinate system of the working machine.

[0025] Fig.11 This is a flowchart showing the process of automatic control of the working machine.

[0026] Fig.12 It is a schematic side view showing a vehicle body coordinate system of the working machine.

[0027] Fig.13A It is a schematic rear view of the working machine showing the position of the working machine based on automatic control.

[0028] Fig. 13B It is a schematic rear view of the working machine showing the position of the working machine based on automatic control.

[0029] Fig.14A It is a schematic rear view of the working machine showing the position of the working machine based on the first setting mode.

[0030] Fig. 14B It is a schematic rear view of the working machine showing the position of the working machine based on the first setting mode.

[0031] Fig.15A It is a schematic rear view of the working machine showing the position of the working machine based on the first setting mode.

[0032] Fig. 15B It is a schematic rear view of the working machine showing the position of the working machine based on the first setting mode.

[0033] Fig.16AIt is a schematic rear view of the working machine showing the position of the working machine based on the second setting mode.

[0034] Fig. 16B It is a schematic rear view of the working machine showing the position of the working machine based on the second setting mode. DETAILED DESCRIPTION

[0035] Hereinafter, embodiments will be described with reference to the drawings. Figure 1 It is a side view of the working machine 1 according to the embodiment. Figure 2 2 is a perspective view of the front part of the working machine 1. The working machine 1 in this embodiment is a motor grader. Figure 1 As shown, the working machine 1 includes a vehicle body 2 and a working machine 3. The working machine 3 is supported so as to be able to move relative to the vehicle body 2. The vehicle body 2 includes a vehicle body frame 4, a tandem drive 5, front wheels 6, and rear wheels 7A and 7B.

[0036] The vehicle body frame 4 supports the front wheel 6 and the working machine 3. The vehicle body 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 articulated to the left and right relative to the rear frame 12. 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 in a state where the articulation angle is 0, that is, the front frame 11 and the rear frame 12 are straight.

[0037] 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 wheels 6 are mounted on the front frame 11.

[0038] 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 body frame 4 in a manner that allows it to 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 machine 3, the vehicle body frame 4 swings around the rear axle 10 (see FIG. 1 ). Fig. 9 ).

[0039] The rear wheels 7A and 7B include a pair of first rear wheels 7A and a pair of second rear wheels 7B. Figure 1 , 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 vehicle body frame 4 relative to the tandem drive 5.

[0040] The working machine 3 is movably connected to the vehicle body 2. The working machine 3 includes a support member 15 and a bulldozer blade 16. The support member 15 is movably connected to the vehicle body 2. The support member 15 supports the bulldozer blade 16. The support member 15 includes a drawbar 17 and a circle 18. The drawbar 17 and the circle 18 are arranged below the front frame 11.

[0041] like Figure 2 As shown, the traction rod 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 rod 17 extends rearward from the front part of the front frame 11. The traction rod 17 is supported so as to be swingable at least in the up-down direction and the left-right direction of the vehicle body 2 with respect to the front frame 11. For example, the shaft support portion 19 includes a ball joint. The traction rod 17 is connected to the front frame 11 via the ball joint so as to be rotatable.

[0042] The rotating disk 18 is connected to the rear part of the drawbar 17. The rotating disk 18 is supported so as to be rotatable relative to the drawbar 17. The bulldozer blade 16 is connected to the rotating disk 18. The bulldozer blade 16 is supported on the drawbar 17 via the rotating disk 18. The bulldozer blade 16 is supported on the rotating disk 18 so as to be rotatable around a tilt axis 21. The tilt axis 21 extends in the left-right direction. The bulldozer blade 16 is supported on the rotating disk 18 so as to be slidable in the left-right direction.

[0043] The working machine 1 includes a plurality of actuators 22-27 for changing the posture of the working machine 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 machine 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 machine 3 relative to the vehicle body 2 by extending and retracting. In the following description, the extension and retraction of the hydraulic cylinder is referred to as a "stroke action".

[0044] In detail, the plurality of hydraulic cylinders 22-26 include a left lift cylinder 22, a right lift cylinder 23, a drawbar shift cylinder 24, a blade tilt cylinder 25, and a blade shift cylinder 26. The left lift cylinder 22 and the right lift cylinder 23 are disposed to be separated from each other in the left-right direction. The left lift cylinder 22 is connected to the left portion of the drawbar 17. The right lift cylinder 23 is connected to the right portion of the drawbar 17. The left lift cylinder 22 and the right lift cylinder 23 are connected to the drawbar 17 so as to be able to swing left and right.

[0045] 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 drawbar 17 swings up and down around the shaft support portion 19. As a result, the bulldozer blade 16 moves up and down.

[0046] 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 direction to the opposite side direction of the left and right sides of the front frame 11. The drawbar 17 is swung left and right around the shaft support portion 19 by the stroke action of the drawbar moving cylinder 24.

[0047] like Figure 1 As shown, the bulldozer blade tilt cylinder 25 is connected to the rotating disk 18 and the bulldozer blade 16. The bulldozer blade 16 rotates around the tilt axis 21 through the stroke action of the bulldozer blade tilt cylinder 25. Figure 2 As shown, the bulldozer blade moving cylinder 26 is connected to the rotating disk 18 and the bulldozer blade 16. Through the stroke action of the bulldozer blade moving cylinder 26, the bulldozer blade 16 slides left and right relative to the rotating disk 18.

[0048] 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 bulldozer blade 16 rotates around a rotary axis extending in the up-down direction.

[0049] Figure 3 Schematic diagram showing the drive system 8 and control system 9 of the working machine 1. Figure 3 As shown, the working 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 hybrid power of an internal combustion engine and an electric motor. The hydraulic pump 32 is driven by the driving source 31 to discharge working oil.

[0050] 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.

[0051] 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. In addition, the swing actuator 27 may also be an electric motor.

[0052] The power transmission device 33 transmits the driving force from the driving source 31 to the rear wheels 7A and 7B. The power transmission device 33 may also include a torque converter and / or a plurality of speed change gears. Alternatively, the power transmission device 33 may also be a transmission such as HST (Hydraulic Static Transmission) or HMT (Hydraulic Mechanical Transmission).

[0053] like Figure 3 As shown, the working machine 1 includes a first operating device 35 and a controller 36. The first operating device 35 can be operated by an operator to change the posture of the working machine 3. The posture of the working machine 3 indicates the position and orientation of the bulldozer 16 relative to the vehicle body 2. Figure 4 2 is a schematic rear view of the working machine 1 showing the posture of the working machine 3. Figure 4 As shown, according to the operation of the first operating device 35, the height of the left end portion 161 and the height of the right end portion 162 of the bulldozer blade 16 are changed.

[0054] According to the operation of the first operating device 35 , the yaw angle θ1 , the pitch angle θ2 , and the roll angle θ3 of the drawbar 17 are changed. Figure 5 1 is a schematic top view of the working machine 1 showing the posture of the working machine 3. Figure 5 As shown in FIG. 1 , the yaw angle θ1 of the drawbar 17 is an inclination angle of the drawbar 17 in the left-right direction relative to the front-rear direction of the vehicle body 2. Alternatively, the yaw angle θ1 of the drawbar 17 may be an inclination angle of the drawbar 17 in the left-right direction relative to the front-rear direction of the front frame 11. The position of the bulldozer blade 16 in the left-right direction changes according to the yaw angle θ1 of the drawbar 17.

[0055] Figure 6 1 is a schematic side view of the working machine 1 showing the posture of the working machine 3. Figure 6 As shown in FIG. 1 , the pitch angle θ2 of the traction bar 17 is an inclination angle of the traction bar 17 in the vertical direction relative to the front-rear direction of the vehicle body 2. Figure 4As 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 .

[0056] Furthermore, according to the operation of the first operating device 35 , the rotation angle θ4 of the rotating disk 18 , the inclination angle θ5 of the bulldozer 16 , and the movement amount W1 of the bulldozer 16 are changed. Figure 7 1 is a schematic top view of the working machine 1 showing the posture of the working machine 3. Figure 7 As shown in FIG. 1 , the rotation angle θ4 of the rotating disk 18 is the rotation angle θ4 of the rotating disk 18 relative to the front-rear direction of the vehicle body 2. Figure 6 As shown, the inclination angle θ5 of the bulldozer blade 16 is an inclination angle of the bulldozer blade 16 about an inclination axis 21 extending in the left-right direction. Figure 8 1 is a schematic top view of the working machine 1 showing the posture of the working machine 3. Figure 8 As shown, the movement amount W1 of the bulldozer 16 is the sliding amount of the bulldozer 16 in the left-right direction relative to the rotating disk 18 .

[0057] The first operating device 35 includes a plurality of operating members 41 to 46 , which 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.

[0058] The plurality of operating members 41-46 include a left lift lever 41, a right lift lever 42, a drawbar moving lever 43, a rotation lever 44, a bulldozer blade tilting lever 45, and a bulldozer blade moving lever 46. According to the operation of the left lift lever 41, the left lift cylinder 22 is extended and retracted. According to the operation of the right lift lever 42, the right lift cylinder 23 is extended and retracted.

[0059] 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 bulldozer blade tilting cylinder 25 is extended and retracted according to the operation of the bulldozer blade tilting lever 45. The bulldozer blade moving cylinder 26 is extended and retracted according to the operation of the bulldozer blade moving lever 46. The plurality of operating members 41-46 each output a signal indicating the operation of the respective operating members 41-46 by the operator.

[0060] The controller 36 drives the working machine 1 by controlling the driving source 31 and the power transmission device 33. In addition, the controller 36 operates the working machine 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 working 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 working machine 1.

[0061] like Figure 3 As shown, the working machine 1 includes a working machine sensor 48 for detecting the posture of the working machine 3 mentioned above. The working machine 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 lengths of the plurality of hydraulic cylinders 22-26 mentioned above. The plurality of sensors S1-S5 include a left lifting sensor S1, a right lifting sensor S2, a traction bar movement sensor S3, a bulldozer blade tilt sensor S4, and a bulldozer blade movement sensor S5.

[0062] 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 bulldozer blade tilt sensor S4 detects the stroke length of the bulldozer blade tilt cylinder 25. The bulldozer blade movement sensor S5 detects the stroke length of the bulldozer blade movement cylinder 26.

[0063] The plurality of sensors S1-S8 include a rotation sensor S6. The rotation sensor S6 detects the rotation angle θ4 of the rotating disk 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 hydraulic cylinder angle sensor S7 and a right hydraulic cylinder angle sensor S8. The left hydraulic 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 hydraulic 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. Through these sensors S1-S8, the posture of the drawbar 17 relative to the vehicle body 2 is detected, and the posture of the bulldozer blade 16 relative to the drawbar 17 is detected. That is, through these sensors S1-S8, the posture of the bulldozer blade 16 relative to the vehicle body 2 is detected.

[0064] The working machine 1 includes a body sensor 49. 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. In addition, the body sensor 49 is not limited to the IMU. The body sensor 49 can be a device that measures the pitch angle and the roll angle of the body 2, and can also be, for example, an inclinometer.

[0065] The vehicle body sensor 49 is mounted on the vehicle body frame 4. Fig. 9 As shown in FIG. 1 , the pitch angle θ6 of the vehicle body 2 is the inclination angle of the vehicle body frame 4 in the vertical direction relative to the horizontal plane. Fig.10As shown, the roll angle θ7 of the vehicle body 2 is the tilt angle of the vehicle body frame 4 in the left-right direction relative to the horizontal plane. In addition, the vehicle body sensor 49 may be installed at other positions of the vehicle body 2 whose relative position relative to the vehicle body frame 4 does not change, and is not limited to the vehicle body frame 4. For example, the vehicle body sensor 49 may be arranged at other positions other than the positions whose relative position relative to the vehicle body frame 4 changes, such as the tandem drive 5 and the drawbar 17.

[0066] The controller 36 obtains the work machine posture data indicating the posture of the work machine 3 relative to the vehicle body 2 based on the signal from the work machine sensor 48. The work machine posture data includes the height of the left end 161 and the height of the right end 162 of the bulldozer 16, the yaw angle θ1, the pitch angle θ2, the roll angle θ3 of the drawbar 17, the rotation angle θ4 of the rotating disk 18, the inclination angle θ5 of the bulldozer 16, and the movement amount W1 of the bulldozer 16. The controller 36 obtains the vehicle body posture data based on the signal from the vehicle body sensor 49.

[0067] The working machine 1 is provided with a mode selection switch 47. The mode selection switch 47 can be operated by an operator to select a control mode of the working machine 3. The mode selection switch 47 is, for example, arranged on a pillar of the cab 13. The mode selection switch 47 can be operated between an operation position of a manual mode and an operation position of an automatic control mode. The controller 36 controls the plurality of actuators 22-27 in a control mode corresponding to the operation position of the mode selection switch 47.

[0068] When the manual mode is selected by the mode selection switch 47, the controller 36 controls the actuators 22-27 according to the operation of the operating members 41-46 to change the posture of the work machine 3. For example, the left lift lever 41 and the right lift lever 42 can be operated in the ascending direction and the descending direction, respectively.

[0069] By operating the left lift lever 41 in the ascending direction, the controller 36 controls the plurality of actuators 22-27 to ascend the left end 161 of the bulldozer 16. By operating the left lift lever 41 in the descending direction, the controller 36 controls the plurality of actuators 22-27 to descend the left end 161 of the bulldozer 16.

[0070] By operating the right lift lever 42 in the ascending direction, the controller 36 controls the plurality of actuators 22-27 to ascend the right end 162 of the bulldozer 16. By operating the right lift lever 42 in the descending direction, the controller 36 controls the plurality of actuators 22-27 to descend the right end 162 of the bulldozer 16.

[0071] The controller 36 moves the bulldozer 16 upward by operating the left lift lever 41 and the right lift lever 42 together in the ascending direction. The controller 36 moves the bulldozer 16 downward by operating the left lift lever 41 and the right lift lever 42 together in the descending direction.

[0072] When the automatic control mode is selected by the mode selection switch 47, the controller 36 performs automatic control of the work machine 3 based on the vehicle body posture data and the work machine posture data. In the automatic control, the controller 36 controls the actuator so that the height of the work machine 3 in the gravity direction is maintained at the target height even if the posture of the vehicle body 2 changes. The processing of the automatic control of the work machine 3 is described below. Fig.11 It is a flowchart showing the processing of automatic control of the working machine 3.

[0073] like Fig.11 As shown, in step S101, the controller 36 determines whether there is an operation of the first operating device 35. When there is no operation input of the first operating device 35 for a certain period of time, the controller 36 can also determine that the operation of the first operating device 35 is no longer performed. When at least one of the above-mentioned operating members 41-46 is being operated, the controller 36 does not perform automatic control of the working machine 3. Therefore, the controller 36 controls the multiple actuators 22-27 according to the operation of the multiple operating members 41-46, thereby changing the posture of the working machine 3. When the operating members 41-46 are not operated, the process enters step S102.

[0074] In step S102, the controller 36 obtains the current posture of the vehicle body 2. Here, the controller 36 obtains the current posture of the vehicle body 2 through the vehicle body posture data. In step S103, the controller 36 obtains the current posture of the working machine 3. Here, the controller 36 obtains the current posture of the working machine 3 through the working machine posture data.

[0075] In step S104, the controller 36 calculates the current height of the work machine 3. The controller 36 calculates the height of the work machine 3 based on the vehicle body posture data and the work machine posture data. For example, the height of the work machine 3 is the height of the left end 161 and the height of the right end 162 of the bulldozer blade 16. Here, the height of the work machine 3 means the height of the left end 161 and the height of the right end 162 of the bulldozer blade 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 a reference point. For example, the height of the working machine 3 means the height of the working machine 3 in the gravity direction from a horizontal plane including the origin O1 of the vehicle body 2.

[0076] like Fig.12As shown, when the working machine 1 moves forward and performs work, the origin O1 of the vehicle body 2 is arranged at 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 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. 9 As 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 in FIG. 1 , the roll angle θ7 of the vehicle body 2 changes with the origin O1 as the center. Fig.10 In the figure, θ8 is the transverse slope angle.

[0077] In step S105, the controller 36 determines the target posture of the work machine 3. The controller 36 calculates the target posture of the work machine 3 so that the heights of the left end 161 and the right end 162 of the bulldozer blade 16 are the target heights. For example, the controller 36 calculates the target pitch angle and the target roll angle of the drawbar 17 so that the heights of the left end 161 and the right end 162 of the bulldozer blade 16 are the target heights. The method of setting the target height will be described later.

[0078] In step S106, the controller 36 controls at least one of the actuators 22-27 so that the heights of the left end 161 and the right end 162 of the bulldozer blade 16 are respectively at the target heights. 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 is the target pitch angle, and the roll angle θ3 of the drawbar 17 is the target roll angle.

[0079] In this case, the controller 36 controls the lift cylinders 22, 23 and the drawbar moving cylinder 24 so that the left-right position of the bulldozer blade 16 does not change. That is, in the working machine 1, due to the extension and retraction of the lift cylinders 22, 23, not only the height direction of the bulldozer blade 16 but also the left-right position of the bulldozer blade 16 changes. Therefore, the controller 36 controls the drawbar moving cylinder 24 to offset the change in the left-right position of the bulldozer blade 16 caused by the extension and retraction of the lift cylinders 22, 23. As a result, the heights of the left end 161 and the right end 162 of the working machine 3 are respectively maintained at the target height, and the left-right position of the working machine 3 is maintained. As a result of the heights of the left end 161 and the right end 162 of the working machine 3 being respectively maintained at the target height, the transverse slope angle θ8 of the working machine 3 also does not change but remains constant.

[0080] The controller 36 repeatedly performs the above-mentioned processing of steps S102 to S106, thereby controlling the actuators 22 to 27 to maintain the left end 161 and the right end 162 of the working machine 3 at the target height. When the first operating device 35 is operated during the automatic control, the controller 36 ends the automatic control (step S101).

[0081] According to the working machine 1 according to the present embodiment described above, the working machine 3 is maintained at the target height of the working machine 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 machine 3 is maintained at the target height of the working machine 3 even if the posture of the vehicle body 2 changes. Therefore, even when the working machine 1 travels on an undulating ground, the working machine 3 is maintained at the target height with high accuracy.

[0082] For example, in Fig. 9 In FIG. 1 , the dozer blade 16′ indicated by a dotted line shows the position of the dozer blade 16 when no automatic control is performed. Fig. 9 As shown, when the front wheel 6 drives onto the ups and downs without automatic control, the bulldozer 16' is Fig.12 However, in the working machine 1 involved in this embodiment, as shown in FIG. Fig. 9 As shown, the bulldozer blade 16 is automatically controlled to be maintained at the target height of the working machine 3 in the direction of gravity. Therefore, even if the front wheel 6 runs over a rise and fall, the bulldozer blade 16 is accurately maintained at the target height by the controller 36 controlling the actuators 22-27.

[0083] Furthermore, through automatic control, even if the posture of the vehicle body 2 changes, the heights of the left end 161 and the right end 162 of the bulldozer 16 are maintained, thereby maintaining the transverse slope angle θ8 of the working machine 3. Figure 4 as well as Fig.10 As shown, the transverse slope angle θ8 is the inclination angle of the bulldozer blade 16 relative to the horizontal plane HP as seen from the rear of the vehicle body 2. Therefore, even when the working machine 1 is traveling on a rough ground, the transverse slope angle θ8 of the working machine 3 is maintained. For example, Fig.13A as well as Fig. 13B FIG. 2 shows the posture of the bulldozer blade 16 when the roll angle θ7 of the vehicle body 2 changes. In the working machine 1 according to the present embodiment, even if the roll angle θ7 of the vehicle body 2 changes from Fig.13A Change to Fig. 13B As shown, the controller 36 controls the actuators 22 to 27 according to the automatic control, so that the slope angle θ8 of the working machine 3 is also maintained.

[0084] Next, the method for setting the target height and the slope angle θ8 of the working machine 3 will be described. Figure 3As shown, the working machine 1 is provided with a second operating device 39. The second operating device 39 can be operated to switch the setting mode of the automatic control to a first setting mode and a second setting mode, wherein the first setting mode is used to individually set the target heights of the left end portion 161 and the right end portion 162 of the bulldozer 16, respectively, and the second setting mode is used to set the target heights of the left end portion 161 and the right end portion 162 of the bulldozer 16 while maintaining the transverse slope angle θ8.

[0085] In the first setting mode, the controller 36 changes the height of the left end 161 and the right end 162 of the bulldozer 16 individually according to the operation of the first operating device 35, and sets the changed height of the left end 161 and the right end 162 of the bulldozer 16 as the target height. In the second setting mode, the controller 36 changes the height of the left end 161 and the right end 162 of the bulldozer 16 while maintaining the transverse slope angle θ8 of the working machine 3 according to the operation of the first operating device 35, and sets the changed height of the left end 161 and the right end 162 of the bulldozer 16 as the target height.

[0086] In detail, the second operating device 39 includes a left setting switch 51 corresponding to the left lifting lever 41, and a right setting switch 52 corresponding to the right lifting lever 42. The left setting switch 51 and the right setting switch 52 can be operated to an ON state and an OFF state, respectively. The left setting switch 51 and the right setting switch 52 are, for example, push button switches. The left setting switch 51 is installed on the left lifting lever 41. The right setting switch 52 is installed on the right lifting lever 42.

[0087] When both the left setting switch 51 and the right setting switch 52 are in the on state, the controller 36 sets the setting mode of the automatic control to the first setting mode. In the first setting mode, the controller 36 changes the height of the left end 161 of the bulldozer 16 according to the operation of the left lift lever 41. The controller 36 changes the height of the right end 162 of the bulldozer 16 according to the operation of the right lift lever 42.

[0088] Fig.14A as well as Fig. 14B FIG. 3 shows the position of the bulldozer 16 when the left lift lever 41 is operated in the first setting mode. The controller 36 moves the left end 161 of the bulldozer 16 from the left end 161 of the bulldozer 16 to the left end 161 of the bulldozer 16 in the gravity direction according to the operation of the left lift lever 41. Fig.14A Move the position shown up or down to Fig. 14B In this case, the slope angle θ8 changes according to the movement of the left end 161. The controller 36 sets the height of the left end 161 when it is determined that the left lift lever 41 is no longer operated as the target height of the left end 161.

[0089] Fig.15A as well as Fig. 15B The position of the bulldozer blade 16 when the right lift lever 42 is operated in the first setting mode is shown. When the right lift lever 42 is operated, the controller 36 moves the right end 162 of the bulldozer blade 16 from the right end 162 of the bulldozer blade 16 to the right end 162 of the bulldozer blade 16 in the direction of gravity. Fig.15A Move the position shown up or down to Fig. 15B In this case, the slope angle θ8 changes according to the movement of the right end 162. The controller 36 sets the height of the right end 162 when it is determined that the right lift lever 42 is no longer operated as the target height of the right end 162.

[0090] When only one of the left setting switch 51 and the right setting switch 52 is in the on state, the controller 36 sets the setting mode of the automatic control to the second setting mode. Fig.16A as well as Fig. 16B The position of the working machine 3 when only the right setting switch 52 is turned on, the left setting switch 51 is turned off, and the left lifting lever 41 is operated is shown. The controller 36 changes the height of the left end 161 of the bulldozer blade 16 while maintaining the transverse slope angle θ8 of the working machine 3 according to the operation of the left lifting lever 41. That is, the controller 36 changes the height of the left end 161 and the right end 162 of the bulldozer blade 16 according to the operation of the left lifting lever 41 to maintain the transverse slope angle θ8.

[0091] When only the left setting switch 51 is turned on, the right setting switch 52 is turned off, and the right lifting lever 42 is operated, the controller 36 changes the height of the right end 162 of the bulldozer blade 16 while maintaining the transverse slope angle θ8 of the working machine 3 according to the operation of the right lifting lever 42. Fig.16A as well as Fig. 16B Likewise, the controller 36 changes the heights of the right end portion 162 and the left end portion 161 of the bulldozer blade 16 in accordance with the operation of the right lift lever 42 so as to maintain the slope angle θ8.

[0092] In addition, when only the left setting switch 51 is turned on and the left lift lever 41 is operated, Fig.14A as well as Fig. 14B Similarly, the controller 36 moves the left end 161 of the bulldozer blade 16 up and down in the vertical direction according to the operation of the left lift lever 41 while maintaining the height of the right end 162 of the bulldozer blade 16. As a result, the slope angle θ8 of the working machine 3 is changed. When only the right setting switch 52 is turned on and the right lift lever 42 is operated, Fig.15A as well as Fig. 15BSimilarly, the controller 36 moves the right end 162 of the bulldozer 16 up and down in the vertical direction according to the operation of the right lift lever 42 while maintaining the height of the left end 161 of the bulldozer 16. Thus, the slope angle θ8 of the working machine 3 is changed.

[0093] An embodiment of the present invention has been described above, but the present invention is not limited to the above embodiment, and various modifications can be made without departing from the gist of the invention.

[0094] The working machine 1 is not limited to a motor grader, but may be another working machine 1 such as a bulldozer. In another working machine 1 such as a bulldozer, the position of the origin O1 can be appropriately set according to the structural characteristics of the working machine 1. The structure of the working machine 3 is not limited to the above-mentioned embodiment, and may also be changed. For example, the working machine 3 may also include a bulldozer 16 and a lifting arm. The lifting arm may also support the bulldozer 16 and be connected to the vehicle body 2. The parameters representing the posture of the working machine 3 are not limited to the above-mentioned embodiment, and may also be changed.

[0095] The plurality of operating members 41-46 are not limited to the above-mentioned embodiments, and may be modified. For example, the operating member is not limited to a lever, and may be a joystick, a switch, or a touch panel or other member. The plurality of operating members 41-46 may also directly operate each of the actuators 22-27.

[0096] The left setting switch 51 and the right setting switch 52 are not limited to the above-mentioned embodiments, and may be modified. For example, the left setting switch 51 and the right setting switch 52 may be sliding or rotating switches. The left setting switch 51 and the right setting switch 52 may also be arranged at positions different from the left lifting lever 41 and the right lifting lever 42, respectively.

[0097] The sensor for detecting the posture of the working machine 3 is not limited to the above-mentioned embodiment, and can also be changed. The sensors S1-S5 can also directly detect the angle without being limited to the stroke length. The working machine 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. Any one of the left hydraulic cylinder angle sensor S7 and the right hydraulic cylinder angle sensor S8 can also be omitted.

[0098] The first operating device 35 may also include an operating member for starting / ending the automatic control. The controller 36 may also start the automatic control according to the operation of the operating member for the automatic control. The controller 36 may also end the automatic control according to the operation of the operating member for the automatic control. The controller 36 may also store the height of the working machine 3 at the start of the automatic control as the target height according to the operation of the operating member for the automatic control.

[0099] In the above-mentioned automatic control, when the posture (angle) or the change of posture (angular velocity) of the vehicle body 2 exceeds the specified value, there is a possibility that the detection error based on the sensors S1-S8 becomes larger. In addition, in the case of a sudden acceleration or deceleration exceeding the specified amount, there is also a possibility that the reaction speed of the sensors S1-S8 cannot keep up. In such a case, the controller 36 can also temporarily release the automatic control. When the difference between the target posture of the working machine 3 and the current posture exceeds the specified threshold, the controller 36 can also temporarily release the automatic control.

[0100] In the above embodiment, the automatic control is described when the working machine 1 moves forward and performs work, but the present invention can also be applied to the case where the working 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.

[0101] In the above-described embodiment, the controller 36 obtains the posture of the working machine 3 when the first operating device 35 is not operated for a certain period of time, and obtains the height of the working machine 3 at this time as the current height of the working machine 3. However, the method for obtaining the current height of the working machine 3 is not limited to this, and may be changed.

[0102] For example, the controller 36 may also obtain the posture of the working machine 3 when an operating device such as a button is operated, and obtain the height of the working machine 3 at this time as the target height of the working machine 3. A switch for increasing or decreasing the obtained target height of the working machine 3 by a predetermined amount may also be provided. The controller 36 may also change the target height of the working machine 3 according to the operation of the switch. In this way, the target posture of the working machine 3 can be finely adjusted.

[0103] The structure of the mode selection switch 47 is not limited to the above-mentioned embodiment, and may be modified. For example, the mode selection switch 47 may be operable in a manual mode, a first setting mode of automatic control, and a second setting mode of automatic control.

[0104] The controller 36 may also input the target angle of the transverse slope angle θ8 through an input device such as a switch or a touch panel, thereby obtaining the target angle of the transverse slope angle θ8. The controller 36 may also calculate the target height of the right end portion 162 based on the target angle of the transverse slope angle θ8 and the height of the left end portion 161 of the bulldozer 16. The controller 36 may also calculate the target height of the left end portion 161 based on the target angle of the transverse slope angle θ8 and the height of the right end portion 162 of the bulldozer 16.

[0105] Alternatively, the controller 36 may obtain the posture of the working machine 3 when an operating device such as a button is operated, and obtain the slope angle θ8 of the working machine 3 at this time as the target angle of the working machine 3. A switch for increasing or decreasing the obtained target angle of the working machine 3 by a predetermined amount may also be provided. The controller 36 may also change the target angle of the working machine 3 according to the operation of the switch. In this way, the target posture of the working machine 3 can be finely adjusted.

[0106] In the above-mentioned embodiment, in the second setting mode, the height of one of the left and right ends of the bulldozer blade 16 corresponding to the setting switch in the on state is maintained, and the height of the other of the left and right ends of the bulldozer blade 16 corresponding to the setting switch in the off state can be changed according to the operation of the lifting lever by the operator. However, contrary to the above-mentioned embodiment, in the second setting mode, the height of one of the left and right ends of the bulldozer blade 16 corresponding to the setting switch in the off state can be maintained, and the height of the other of the left and right ends of the bulldozer blade 16 corresponding to the setting switch in the on state can be changed according to the operation of the lifting lever by the operator.

[0107] Industrial Applicability

[0108] According to the present disclosure, even if the posture of the vehicle body changes, the height and the slope angle of the working machine in the gravity direction are maintained. Therefore, even when the working machine travels on an undulating ground, the height and the slope angle of the working machine are maintained with high accuracy.

[0109] [Explanation of Reference Numerals]

[0110] 2: vehicle body, 3: work machine, 4: vehicle body frame, 22-27: actuator, 35: first operating device, 36: controller, 39: second operating device, 41: left lifting lever, 42: right lifting lever, 51: left setting switch, 52: right setting switch.

Claims

1. A working machine having: Car body; A working machine is supported so as to be able to move relative to the vehicle body; an actuator connected to the working machine to move the working machine; a first operating device operated to set a target height of the working machine in the gravity direction and a transverse slope angle representing an inclination angle of the working machine relative to a horizontal plane; as well as Controller, The controller obtains a target height of the working machine. The controller controls the actuator so that the height of the working machine in the gravity direction is maintained at the target height even if the posture of the vehicle body changes.

2. The working machine according to claim 1, wherein: The working machine further includes a second operating device that is operated to switch between a first setting mode and a second setting mode for setting a target height of the working machine. In the first setting mode, the controller individually sets the target heights of the left and right ends of the working machine according to the operation of the first operating device. In the second setting mode, the controller sets the target height of the working machine while maintaining the cross slope angle.

3. The working machine according to claim 2, wherein: The first operating device includes a left lifting rod and a right lifting rod which can be operated in an ascending direction and a descending direction respectively. The second operating device comprises: a left setting switch corresponding to the left lifting lever; and The right setting switch corresponds to the right lifting lever. The left setting switch and the right setting switch can be operated to an on state and an off state respectively, When the left setting switch is in the on state, the controller changes the height of the left end of the working machine while maintaining the height of the right end of the working machine according to the operation of the left lifting lever, thereby changing the transverse slope angle of the working machine. When the right setting switch is in the on state, the controller changes the height of the right end of the work machine while maintaining the height of the left end of the work machine according to the operation of the right lift lever, thereby changing the slope angle of the work machine.

4. The working machine according to claim 3, wherein: When the left setting switch is in the off state, the controller changes the height of the working machine while maintaining the transverse slope angle of the working machine according to the operation of the left lifting lever. The controller sets the changed height of the working machine as the target height.

5. The working machine according to claim 3, wherein: When the right setting switch is in the off state, the controller changes the height of the working machine while maintaining the transverse slope angle of the working machine according to the operation of the right lifting lever. The controller sets the changed height of the working machine as the target height.

6. A method for controlling a working machine, the working machine comprising: a vehicle body; a working machine supported so as to be movable relative to the vehicle body; and an actuator connected to the working machine to move the working machine, The method has: setting the target height and the transverse slope angle of the working machine according to the operation of a first operating device operated to set the target height of the working machine in the gravity direction and the transverse slope angle representing the inclination angle of the working machine with respect to a horizontal plane; as well as The actuator is controlled so that the height of the working machine in the gravity direction is maintained at the target height even if the posture of the vehicle body changes.

7. The method according to claim 6, comprising: switching between a first setting mode and a second setting mode for setting a target height of the working machine according to an operation of a second operating device; In the first setting mode, the target heights of the left and right ends of the working machine are individually set according to the operation of the first operating device; and In the second setting mode, the target height of the working machine is set while maintaining the slope angle.

8. The method of claim 7, wherein: The first operating device includes a left lifting rod and a right lifting rod which can be operated in an ascending direction and a descending direction respectively. The second operating device comprises: a left setting switch corresponding to the left lifting lever; and The right setting switch corresponds to the right lifting lever. The left setting switch and the right setting switch can be operated to an on state and an off state respectively, The method has: When the left setting switch is in the on state, the height of the left end of the working machine is changed while maintaining the height of the right end of the working machine according to the operation of the left lifting lever, thereby changing the slope angle of the working machine; and When the right setting switch is in the on state, the height of the left end of the working machine is changed while the height of the right end of the working machine is maintained according to the operation of the right lift lever, thereby changing the slope angle of the working machine.

9. The method according to claim 8, comprising: When the left setting switch is in an OFF state, the height of the working machine is changed while maintaining the slope angle of the working machine according to the operation of the left lifting lever; and The changed height of the working machine is set as the target height.

10. The method according to claim 8, comprising: When the right setting switch is in an OFF state, the height of the working machine is changed while maintaining the transverse slope angle of the working machine according to the operation of the right lifting lever; and The changed height of the working machine is set as the target height.

11. A method for controlling a working machine, the working machine comprising: a vehicle body; a working machine supported so as to be movable relative to the vehicle body; and an actuator connected to the working machine to move the working machine, The method has: setting target heights of each of the left and right ends of the working machine according to an operation of a first operating device that is operated to set a target height of the working machine in the gravity direction; and The actuator is controlled so that the heights of the left and right ends of the working machine in the gravity direction are maintained at the target heights even if the posture of the vehicle body changes, thereby maintaining the slope angle.

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