Work machine and method for controlling a work machine

Abstract

The controller acquires the vehicle body posture data. The controller acquires the working machine posture data. The controller calculates the height of the working machine in the gravitational direction from the reference point of the vehicle body on the basis of the vehicle body posture data and the working machine posture data. The controller controls the actuator so that the height of the working machine in the gravitational direction is maintained even if the posture of the vehicle body changes.

Description

Technical Field

[0001] This invention relates to a work machine and a method for controlling the work machine. Background Technology

[0002] The work machinery consists of a chassis, a workpiece, and actuators. The actuators are, for example, hydraulic cylinders. The actuators are driven by the operator, causing the workpiece to move. For example, a motorized grader, as a workpiece, has a bulldozer blade. The motorized grader, as a chassis, has a tandem drive and a frame. The bulldozer blade is supported by the frame. The frame rotatably supports the front wheels. The tandem drive supports the rear wheels. The operator moves the bulldozer blade up and down by operating a lever on the workpiece.

[0003] In the aforementioned motorized grader, the height of the bulldozer blade changes as the front wheels traverse uneven terrain due to the change in the frame's posture. Patent Document 1 discloses a technology corresponding to this problem. In Patent Document 1, the controller calculates the change in bulldozer blade height based on the relative rotation angle between the frame and the tandem drive. The controller moves the bulldozer blade up and down according to the change in blade height. This maintains the bulldozer blade at a predetermined height.

[0004] Existing technical documents

[0005] Patent documents

[0006] Patent Document 1: Japanese Patent Application Publication No. 2001-193095 Summary of the Invention

[0007] The problem that the invention will solve

[0008] However, in the motorized grader of Patent Document 1, when the overall posture of the 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 is different from the actual height of the bulldozer blade. Therefore, it is difficult to maintain the bulldozer blade at a predetermined height with high precision relative to the ground. In this invention, even when the machine is traveling on undulating ground, it can be maintained at the target height with high precision.

[0009] Methods for solving problems

[0010] One aspect of the present invention is a work machine comprising: a vehicle body, a work machine, an actuator, a vehicle body sensor, a work machine sensor, and a controller. The work machine is movably supported relative to the vehicle body. The actuator is connected to the work machine. The actuator actuates the work machine. The vehicle body sensor detects vehicle body attitude data representing the attitude of the vehicle body. The work machine sensor detects work machine attitude data representing the attitude of the work machine.

[0011] The controller acquires vehicle body attitude data. The controller acquires machine attitude data. Based on the vehicle body attitude data and machine attitude data, the controller calculates the machine's height in the gravity direction relative to a reference point on the vehicle body. The controller controls the actuators to maintain the machine's height in the gravity direction even if the vehicle body's attitude changes.

[0012] Another aspect of the invention is a method for controlling a work machine, the work machine comprising a chassis, a workpiece, and an actuator. The workpiece is movably supported relative to the chassis. The actuator is connected to the workpiece. The actuator causes the workpiece to move.

[0013] The method includes: acquiring vehicle body posture data representing the vehicle body posture; acquiring machine posture data representing the machine posture; calculating the height of the machine in the gravity direction from a reference point on the vehicle body based on the vehicle body posture data and the machine posture data; and controlling the actuator to maintain the height of the machine in the gravity direction even if the vehicle body posture changes.

[0014] Invention Effects

[0015] According to the present invention, the height of the working machine in the direction of gravity is maintained even if the posture of the vehicle body changes. Therefore, the height of the working machine can be maintained with high precision even when the working machine is traveling on undulating ground. Attached Figure Description

[0016] Figure 1 This is a side view of the operating machinery in the implementation method.

[0017] Figure 2 It is a three-dimensional view of the front of the operating machinery.

[0018] Figure 3 This is a schematic diagram showing the drive system and control system of the operating machinery.

[0019] Figure 4 This is a schematic rear view showing the posture of the machine.

[0020] Figure 5 It is a schematic top view of the working machine to show its posture.

[0021] Figure 6 This is a schematic enlarged side view of the working machinery, showing its posture.

[0022] Figure 7 It is a schematic top view of the working machine to show its posture.

[0023] Figure 8 It is a schematic top view of the working machine to show its posture.

[0024] Figure 9It is a schematic side view representing the vehicle coordinate system of the operating machinery.

[0025] Figure 10 This is a schematic rear view representing the vehicle coordinate system of the operating machinery.

[0026] Figure 11 This is a flowchart illustrating the automatic control process of the machine.

[0027] Figure 12 It is a schematic side view representing the vehicle coordinate system of the operating machinery. Detailed Implementation

[0028] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. Figure 1 This is a side view of the operating machinery 1 in the embodiment. Figure 2 This is a perspective view of the front of the working machine 1. In this embodiment, the working machine 1 is a motorized grader. Figure 1 As shown, the working machine 1 includes a body 2 and a working machine 3. The working machine 3 is movably supported relative to the body 2. The body 2 includes a body frame 4, a series drive 5, front wheels 6, and rear wheels 7A and 7B.

[0029] The vehicle frame 4 supports the front wheels 6 and the work machine 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 rear frame 12 in the left and right directions. Furthermore, in the following description, the directions of front, back, left, and right refer to the directions of the vehicle body 2 in the front, back, left, and right directions when the hinge angle is 0, that is, when the front frame 11 and the rear frame 12 are perpendicular.

[0030] The rear frame 12 is equipped with a driver's compartment 13 and a power compartment 14. The driver's compartment 13 is equipped with a driver's seat (not shown). The power compartment 14 is equipped with a drive system described later. The front frame 11 extends forward from the rear frame 12. The front wheel 6 is mounted on the front frame 11.

[0031] The tandem drive 5 is connected to the rear frame 12. The tandem drive 5 supports 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 oscillates around the rear axle 10, supporting the rear frame 12 of the vehicle body frame 4. When the front wheels 6 move up and down due to the undulations of the road surface not leveled by the work machine 3, the vehicle body frame 4 oscillates around the rear axle 10 (see reference). Figure 9 ).

[0032] The rear wheels 7A and 7B consist of a first rear wheel 7A and a second rear wheel 7B. It should be noted that... Figure 1Only the first rear wheel 7A and the second rear wheel 7B on the left side are shown. The second rear wheel 7B is positioned behind the first rear wheel 7A. The rear axle 10 is positioned between the first rear wheel 7A and the second rear wheel 7B. The rear axle 10 serves as the pivot point of the vehicle frame 4 relative to the tandem drive 5.

[0033] The work machine 3 is movably connected to the vehicle body 2. The work 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 rotary disc 18. The drawbar 17 and the rotary disc 18 are arranged below the front frame 11.

[0034] like Figure 2 As shown, the tow bar 17 is connected to the axle support 19 of the front frame 11. The axle support 19 is located at the front of the front frame 11. The tow bar 17 extends rearward from the front of the front frame 11. The tow bar 17 is supported relative to the front frame 11, at least in the vertical and horizontal directions of the vehicle body 2, allowing it to swing. For example, the axle support 19 includes a ball joint. The tow bar 17 is rotatably connected relative to the front frame 11 via the ball joint.

[0035] A rotating disk 18 is connected to the rear of a drawbar 17. The rotating disk 18 is rotatably supported relative to the drawbar 17. A 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 rotatably supported on the rotating disk 18 about an inclined axis 21. The inclined axis 21 extends in the left-right direction. The bulldozer blade 16 is slidably supported on the rotating disk 18 in the left-right direction.

[0036] The working machine 1 includes multiple actuators 22-27 for changing the posture of the working machine 3. Each actuator 22-27 includes multiple hydraulic cylinders 22-26. The multiple hydraulic cylinders 22-26 are connected to the working machine 3. The multiple hydraulic cylinders 22-26 extend and retract hydraulically. The extension and retraction of the multiple hydraulic cylinders 22-26 changes the posture of the working machine 3 relative to the vehicle body 2. In the following description, the extension and retraction of the hydraulic cylinders is referred to as "stroke action".

[0037] Specifically, the plurality of hydraulic cylinders 22-26 include: a left lifting hydraulic cylinder 22, a right lifting hydraulic cylinder 23, a drawbar moving cylinder 24, a bulldozer blade tilting hydraulic cylinder 25, and a bulldozer blade moving cylinder 26. The left lifting hydraulic cylinder 22 and the right lifting hydraulic cylinder 23 are arranged separately from each other in the left-right direction. The left lifting hydraulic cylinder 22 is connected to the left portion of the drawbar 17. The right lifting hydraulic cylinder 23 is connected to the right portion of the drawbar 17. The left lifting hydraulic cylinder 22 and the right lifting hydraulic cylinder 23 are connected in a manner that allows them to swing left and right relative to the drawbar 17.

[0038] The left lifting hydraulic cylinder 22 and the right lifting hydraulic cylinder 23 are connected to the front frame 11 in a left-right swinging manner. Specifically, the left lifting hydraulic cylinder 22 and the right lifting hydraulic cylinder 23 are connected to the front frame 11 via a lifting bracket 29. The lifting bracket 29 is connected to the front frame 11. The lifting bracket 29 supports the left lifting hydraulic cylinder 22 and the right lifting hydraulic cylinder 23 in a left-right swinging manner. Through the stroke of the left lifting hydraulic cylinder 22 and the right lifting hydraulic cylinder 23, the drawbar 17 swings up and down around the shaft support 19. This causes the bulldozer blade 16 to move up and down.

[0039] The tow bar moving cylinder 24 is connected to the tow bar 17 and the front frame 11. The tow bar moving cylinder 24 is connected to the front frame 11 via the lifting bracket 29. The tow bar moving cylinder 24 is oscillatingly connected relative to the front frame 11. The tow bar moving cylinder 24 is oscillatingly connected relative to the tow bar 17. The tow bar moving cylinder 24 extends diagonally downwards from the front frame 11 toward the tow bar 17. The tow bar moving cylinder 24 extends from one side of the front frame 11 to the opposite side. Through the stroke of the tow bar moving cylinder 24, the tow bar 17 oscillates left and right around the shaft support 19.

[0040] like Figure 1 As shown, the bulldozer blade tilting hydraulic cylinder 25 is connected to the rotary table 18 and the bulldozer blade 16. Through the stroke of the bulldozer blade tilting hydraulic cylinder 25, the bulldozer blade 16 rotates around the tilting axis 21. Figure 2 As shown, the bulldozer blade moving cylinder 26 is connected to the rotary disk 18 and the bulldozer blade 16. The bulldozer blade 16 slides left and right relative to the rotary disk 18 through the stroke movement of the bulldozer blade moving cylinder 26.

[0041] Multiple actuators 22-27 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. As a result, the bulldozer blade 16 rotates about a rotation axis extending in the vertical direction.

[0042] Figure 3 This is a schematic diagram showing the drive system 8 and control system 9 of the operating machinery 1. (For example...) Figure 3 As shown, the working machine 1 includes: a drive source 31, a hydraulic pump 32, a power transmission device 33, and a control valve 34. The drive source 31 is, for example, an internal combustion engine. Alternatively, the drive source 31 may also be an electric motor or a hybrid of an internal combustion engine and an electric motor. The hydraulic pump 32 is driven by the drive source 31 to discharge working oil.

[0043] Control valve 34 is connected to hydraulic pump 32 and multiple hydraulic cylinders 22-26 via a hydraulic circuit. Control valve 34 includes multiple valves respectively connected to the multiple hydraulic cylinders 22-26. Control valve 34 controls the flow rate of working oil supplied from hydraulic pump 32 to multiple hydraulic cylinders 22-26.

[0044] In this embodiment, the rotary actuator 27 is a hydraulic motor. A control valve 34 is connected to the hydraulic pump 32 and the rotary actuator 27 via a hydraulic circuit. The control valve 34 controls the flow rate of the working oil supplied from the hydraulic pump 32 to the rotary actuator 27. Alternatively, the rotary actuator 27 can also be an electric motor.

[0045] The power transmission device 33 transmits the driving force from the drive source 31 to the rear wheels 7A and 7B. The power transmission device 33 may also include a torque converter and / or multiple transmission gears. Alternatively, the power transmission device 33 may also be a transmission such as an HST (Hydraulic Static Transmission) or HMT (Hydraulic Mechanical Transmission).

[0046] like Figure 3 As shown, the working machine 1 includes an operating device 35 and a controller 36. The 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 refers to the position and orientation of the bulldozer blade 16 relative to the vehicle body 2. Figure 4 This is a schematic rear view of the working machine 1, showing the posture of the working machine 3. (Example) Figure 4 As shown, the height of the left end 161 and the right end 162 of the bulldozer blade 16 can be changed according to the operation of the operating device 35.

[0047] According to the operation of the operating device 35, the lateral sway angle θ1, longitudinal sway angle θ2 and lateral deflection angle θ3 of the traction rod 17 are changed. Figure 5 This is a schematic top view of the working machine 1, showing the posture of the working machine 3. For example... Figure 5 As shown, the yaw angle θ1 of the drawbar 17 is the tilt 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 can also be the tilt 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 varies according to the yaw angle θ1 of the drawbar 17.

[0048] Figure 6 This is a schematic side view of the working machine 1, showing the posture of the working machine 3. For example... Figure 6 As shown, the longitudinal swing angle θ2 of the tow bar 17 is the tilt angle of the tow bar 17 in the vertical direction relative to the front-rear direction of the vehicle body 2. Figure 4 As shown, the side slip angle θ3 of the traction rod 17 is the tilt angle of the traction rod 17 about the side slip axis A1 extending in the front-rear direction of the vehicle body 2.

[0049] Furthermore, depending on the operation of the operating device 35, the rotation angle θ4 of the rotary disk 18, the tilt angle θ5 of the bulldozer blade 16, and the movement amount W1 of the bulldozer blade 16 can be changed. Figure 7 This is a schematic top view of the working machine 1, showing the posture of the working machine 3. For example... Figure 7 As shown, 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 tilt angle θ5 of the bulldozer blade 16 is the tilt angle of the bulldozer blade 16 about the tilt axis 21 extending in the left and right direction. Figure 8 This is a schematic top view of the working machine 1, showing the posture of the working machine 3. For example... Figure 8 As shown, the amount of movement W1 of the bulldozer blade 16 is the amount of sliding of the bulldozer blade 16 relative to the rotary disk 18 in the left and right directions.

[0050] The operating device 35 includes multiple operating components 41-46. The multiple operating components 41-46 are respectively provided for the left lifting hydraulic cylinder 22, the right lifting hydraulic cylinder 23, the traction rod moving cylinder 24, the bulldozer blade tilting hydraulic cylinder 25, the bulldozer blade moving cylinder 26, and the rotary actuator 27.

[0051] Multiple operating components 41-46 include a left lifting rod 41, a right lifting rod 42, a traction rod shift lever 43, a rotating rod 44, a bulldozer blade tilting lever 45, and a bulldozer blade shift lever 46. The left lifting hydraulic cylinder 22 extends and retracts according to the operation of the left lifting rod 41. The right lifting hydraulic cylinder 23 extends and retracts according to the operation of the right lifting rod 42.

[0052] The drawbar movement cylinder 24 extends and retracts according to the operation of the drawbar gear shift lever 43. The rotary actuator 27 rotates according to the operation of the rotation lever 44. The bulldozer blade tilting hydraulic cylinder 25 extends and retracts according to the operation of the bulldozer blade tilting lever 45. The bulldozer blade movement cylinder 26 extends and retracts according to the operation of the bulldozer blade gear shift lever 46. Multiple operating components 41-46 output signals indicating the operator's operation of each operating component 41-46.

[0053] The controller 36 drives the machine 1 by controlling the drive source 31 and the power transmission device 33. Additionally, the controller 36 actuates the machine 1 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, for example, is a CPU, which executes programs for controlling the machine 1. The storage device 38 includes RAM and ROM, as well as auxiliary storage devices such as SSDs or HDDs. The storage device 38 stores programs and data for controlling the machine 1.

[0054] like Figure 3As shown, the working machine 1 includes a working machine sensor 48 for detecting the posture of the aforementioned working machine 3. The working machine sensor 48 includes multiple sensors S1-S8. The multiple sensors S1-S8 are, for example, magnetic sensors. However, the multiple sensors S1-S8 can also be sensors of other types, such as optical sensors. The multiple sensors S1-S5 detect the stroke length of the aforementioned multiple hydraulic cylinders 22-26. The multiple sensors S1-S5 include a left lifting sensor S1, a right lifting sensor S2, a drawbar movement sensor S3, a bulldozer blade tilt sensor S4, and a bulldozer blade movement sensor S5.

[0055] Left lifting sensor S1 detects the stroke length of left lifting hydraulic cylinder 22. Right lifting sensor S2 detects the stroke length of right lifting hydraulic cylinder 23. Drawbar movement sensor S3 detects the stroke length of drawbar movement cylinder 24. Bulldozer blade tilt sensor S4 detects the stroke length of bulldozer blade tilt hydraulic cylinder 25. Bulldozer blade movement sensor S5 detects the stroke length of bulldozer blade movement cylinder 26.

[0056] Multiple sensors S1-S8 include a rotation sensor S6. The rotation sensor S6 detects the rotation angle θ4 of the rotary disk 18. Multiple sensors S1-S8 output signals representing the detected stroke length and the rotation angle θ4. Multiple sensors S1-S8 also include a left cylinder angle sensor S7 and a right cylinder angle sensor S8. The left cylinder angle sensor S7 detects the left-right swing angle of the left lifting hydraulic cylinder 22 relative to the lifting bracket 29. The right cylinder angle sensor S8 detects the left-right swing angle of the right lifting hydraulic cylinder 23 relative to the lifting bracket 29. Through these sensors S1-S8, the attitude of the drawbar 17 relative to the vehicle body 2 and the attitude of the bulldozer blade 16 relative to the drawbar 17 can be detected. That is, through these sensors S1-S8, the attitude of the bulldozer blade 16 relative to the vehicle body 2 can be detected.

[0057] The operating machine 1 includes a vehicle body sensor 49. The vehicle body sensor 49 is, for example, an IMU (Inertial Measurement Unit). The vehicle body sensor 49 detects vehicle body attitude data representing the attitude of the vehicle body 2. The vehicle body attitude data includes the yaw angle and sideslip angle of the vehicle body 2. Furthermore, the vehicle body sensor 49 is not limited to an IMU. The vehicle body sensor 49 can be any means of measuring the yaw angle and sideslip angle of the vehicle body 2, for example, it could be a tiltmeter.

[0058] Vehicle body sensor 49 is mounted on vehicle body frame 4. Therefore, as... Figure 9 As shown, the longitudinal yaw angle θ6 of the vehicle body 2 is the tilt angle in the vertical direction relative to the horizontal vehicle frame 4. Figure 10As shown, the sideslip angle θ7 of the vehicle body 2 is the tilt angle in the left-right direction relative to the horizontal vehicle frame 4. Furthermore, the vehicle body sensor 49 is not limited to the vehicle frame 4 and can be installed at other locations on the vehicle body 2 where its relative position to the vehicle frame 4 does not change. For example, the vehicle body sensor 49 can also be configured at locations other than those where the relative positions of the series driver 5 and the tow bar 17 relative to the vehicle frame 4 change.

[0059] The controller 36 acquires machine attitude data, representing the orientation of the machine 3 relative to the vehicle body 2, based on signals from the machine sensor 48. The machine attitude data includes the height of the left end 161 and right end 162 of the bulldozer blade 16, the yaw angle θ1, yaw angle θ2, and lateral tilt angle θ3 of the drawbar 17, the rotation angle θ4 of the rotary disc 18, the tilt angle θ5 of the bulldozer blade 16, and the movement amount W1 of the bulldozer blade 16. The controller 36 acquires vehicle body attitude data based on signals from the vehicle body sensor 49. The controller 36 controls multiple actuators 22-27 to change the orientation of the machine 3 according to the operation of multiple operating components 41-46.

[0060] Furthermore, the controller 36 performs automatic control of the work machine 3 based on the aforementioned vehicle body posture data and work machine posture data. In the automatic control of the work machine 3, the controller 36 controls the left lifting hydraulic cylinder 22 and the right lifting hydraulic cylinder 23 to maintain the work machine 3 at the target height. The processing of the automatic control of the work machine 3 will be explained below. Figure 11 This is a flowchart illustrating the automatic control process of machine 3.

[0061] like Figure 11 As shown, in step S101, the controller 36 determines whether there is an operation of the operating device 35. If there is no operation input from the operating device 35 within a certain period, the controller 36 can also determine that it will not perform an operation of the operating device 35. When at least one of the operating components 41-46 is operated, the controller 36 does not perform automatic control of the machine 3. Therefore, the controller 36 controls multiple actuators 22-27 to change the posture of the machine 3 according to the operation of multiple operating components 41-46. When the operating components 41-46 are not operated, the process proceeds to step S102.

[0062] In step S102, the controller 36 obtains the current attitude of the vehicle body 2. Here, the controller 36 obtains the current attitude of the vehicle body 2 based on the vehicle body attitude data. In step S103, the controller 36 obtains the current attitude of the work machine 3. Here, the controller 36 obtains the current attitude of the work machine 3 based on the work machine attitude data.

[0063] 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 attitude data and the work machine attitude data. For example, the height of the work machine 3 is the height of the left end 161 and the right end 162 of the bulldozer blade 16. Here, the height of the work machine 3 is... Figure 12 The origin O1 of the vehicle body 2 shown is the reference point, representing the height in the direction of gravity from the origin O1. For example, the height of the work machine 3 represents the height of the work machine 3 in the direction of gravity from the horizontal plane including the origin O1 of the vehicle body 2.

[0064] like Figure 12 As shown, when the working machine 1 is moving forward to perform operations, the origin O1 of the vehicle body 2 is positioned at the series drive 5. For example, the origin O1 of the vehicle body 2 is positioned at the center in the left-right direction of the rear axle 10. Figure 12 In the diagram, the Z1 axis indicates the direction of gravity. The X1 axis indicates the forward and backward direction of the vehicle body 2, perpendicular to the direction of gravity. Figure 4 In the diagram, the Y1 axis represents the left-right direction of vehicle body 2, perpendicular to the direction of gravity. The attitude of vehicle body 2 changes around its origin O1. For example... Figure 9 As shown, the longitudinal yaw angle θ6 of vehicle body 2 varies around the origin O1. Figure 10 As shown, the sideslip angle θ7 of vehicle body 2 varies with the origin O1 as the center.

[0065] In step S105, the controller 36 determines the target attitude of the work machine 3. The controller 36 calculates the target attitude of the work machine 3 so that the height of the work machine 3 becomes the target height. In addition, the controller 36 stores the height of the work machine 3 when it is determined that the operation of the operating device 35 is not in progress as the target height. For example, the controller 36 calculates the target yaw angle and the target sideslip angle of the traction rod 17 so that the height of the work machine 3 becomes the target height.

[0066] In step S106, controller 36 controls at least one of actuators 22-27 to make the height of the work machine 3 the target height. For example, controller 36 controls lifting hydraulic cylinders 22 and 23 and traction rod moving cylinder 24 to make the yaw angle θ2 of traction rod 17 the target yaw angle, and the sideslip angle θ3 of traction rod 17 the target sideslip angle.

[0067] In this situation, the controller 36 controls the lifting hydraulic cylinders 22 and 23 and the traction rod moving cylinder 24 to ensure that the position of the bulldozer blade 16 does not change in the left-right direction. That is, in the working machine 1, the extension and retraction of the lifting hydraulic cylinders 22 and 23 not only changes the height of the bulldozer blade 16, but also changes its position in the left-right direction. Therefore, the controller 36 controls the traction rod moving cylinder 24 to counteract the change in the position of the bulldozer blade 16 in the left-right direction caused by the extension and retraction of the lifting hydraulic cylinders 22 and 23. As a result, the height of the working machine 3 is maintained at the target height, and the position of the working machine 3 in the left-right direction is maintained.

[0068] The controller 36 controls the actuators 22-27 by repeating the processes of steps S102 to S106 above, so that the work machine 3 is kept at the target height. In addition, the controller 36 terminates automatic control when the operating device 35 is operated automatically (step S101).

[0069] According to the above-described embodiment of the working machine 1, the working machine 3 is maintained at a target height by automatic control. The target height is the height in the direction of gravity from the origin O1 of the vehicle body 2. Even if the posture of the vehicle body 2 changes, the working machine 3 can maintain the target height. Therefore, even when the working machine 1 is traveling on undulating ground, the working machine 3 can maintain the target height with high precision.

[0070] For example in Figure 9 In the diagram, the dotted line indicating the bulldozer blade 16' shows the position of the bulldozer blade 16 without automatic control. For example... Figure 9 As shown, without automatic control, when the current wheel 6 is in an undulating state, the bulldozer blade 16' rises to... Figure 12 Above the position of the bulldozer blade 16 shown. However, in the working machine 1 of this embodiment, as... Figure 9 As shown, through automatic control, the bulldozer blade 16 maintains the target height of the work machine 3 in the direction of gravity. Therefore, even if the front wheel 6 is in an undulating state, the bulldozer blade 16 can maintain the target height with high precision by controlling the actuators 22-27 by the controller 36.

[0071] The above describes one embodiment of the present invention, but the present invention is not limited to the above embodiment and various modifications can be made without departing from the spirit of the invention.

[0072] The working machine 1 is not limited to a motorized grader, but can also be other working machines such as an excavator. In other working machines such as excavators, the position of the origin O1 can be appropriately set according to the structural characteristics of the working machine. The structure of the working machine 3 is not limited to the above-described embodiment and can be modified. For example, the working machine 3 may include a bulldozer blade and a lifting arm. The lifting arm may also support the bulldozer blade and be connected to the vehicle body. The parameters representing the attitude of the working machine 3 are not limited to the above-described embodiment and can also be modified.

[0073] The multiple operating components 41-46 are not limited to the above-described embodiments and can be modified. For example, the operating components are not limited to levers, but can also be other components such as joysticks, switches, or touch panels. The multiple operating components 41-46 can also directly operate the actuators 22-27 respectively.

[0074] The sensors used to detect the attitude of the machine 3 are not limited to the above-described embodiments and can be modified. Sensors S1-S5 are not limited to long strokes and can also directly detect angles. The machine sensor 48 can also include an IMU (Inertial Measurement Unit). The IMU can also be mounted on the tow bar 17. The attitude of the tow bar 17 can also be detected via the IMU. Either the left cylinder angle sensor S7 or the right cylinder angle sensor S8 can be omitted.

[0075] The operating device 35 may also include an operating component for automatic control. The controller 36 may also initiate automatic control based on the operation of the operating component for automatic control. The controller 36 may also terminate automatic control based on the operation of the operating component for automatic control. The controller 36 may also store the height of the work machine 3 at the start of automatic control as the target height based on the operation of the operating component for automatic control.

[0076] In the aforementioned automatic control, if the attitude (angle) or change in attitude (angular velocity) of the vehicle body 2 exceeds a predetermined value, the detection error of sensors S1-S8 may increase. Furthermore, if a rapid acceleration or deceleration exceeding a predetermined amount occurs, the reaction speed of sensors S1-S8 may not be sufficient. In such cases, controller 36 may temporarily deactivate automatic control. Controller 36 may temporarily deactivate automatic control if the difference between the target attitude and the current attitude of the work machine 3 exceeds a predetermined threshold.

[0077] In the above embodiments, automatic control was described when the working machine 1 is moving forward to perform operations. However, the present invention can also be applied when the working machine 1 is moving backward to perform operations. In this case, the origin O of the vehicle body 2 can also be the center position between the left and right front wheels 6.

[0078] In the above embodiment, the controller 36 obtains the posture of the machine 3 when the operating device 35 is not operated for a certain period of time, obtains the height of the machine 3 at this time, and uses it as the current height of the machine 3. However, the method for obtaining the current height of the machine 3 is not limited to this and can be changed. For example, the controller 36 can also obtain the posture of the machine 3 when the operating device such as the button is operated, and use the height of the machine 3 at this time as the current height of the machine 3. A switch for increasing or decreasing the obtained height of the machine 3 by a predetermined amount can also be provided. The controller 36 can change the target posture of the machine 3 according to the operation of the switch. Thus, the target posture of the machine 3 can be fine-tuned.

[0079] Industrial availability

[0080] According to the present invention, even when the working machine is traveling on undulating ground, it can maintain the target height with high precision.

[0081] Explanation of reference numerals in the attached figures

[0082] 2: Vehicle body; 3: Working machine; 4: Vehicle frame; 5: Series drive; 6: Front wheel; 7A, 7B: Rear wheel; 22-27: Actuator; 35: Operating device; 36: Controller; 48: Working machine sensor; 49: Vehicle body sensor

Claims

1. A type of operating machinery, characterized in that, have: Vehicle body; A work machine that is movably supported relative to the vehicle body; An actuator connected to the work machine to cause the work machine to move; Vehicle sensors that detect vehicle attitude data representing the vehicle's posture; A machine sensor that detects machine attitude data representing the attitude of the machine; Controller The controller performs the following control functions. Obtain the vehicle body attitude data; Obtain the attitude data of the machine; Calculate the height of the work machine in the gravity direction from the reference point of the vehicle body based on the vehicle body posture data and the work machine posture data; The actuator is controlled so that the height of the work machine in the direction of gravity is maintained even if the attitude of the vehicle body changes.

2. The operating machinery as described in claim 1, characterized in that, The vehicle body includes: Front wheel; The vehicle frame that supports the front wheels and the work machine; rear wheel; The vehicle includes a rear axle that supports the rear wheels and extends in the left-right direction, and a series drive that supports the vehicle frame oscillating about the rear axle. Even if the vehicle frame swings about the rear axle relative to the series drive, the controller maintains the height of the work machine in the direction of gravity.

3. The operating machinery as described in claim 2, characterized in that, The reference point of the vehicle body is configured in the series drive.

4. The operating machinery as described in claim 1, characterized in that, It also has operating devices that can be operated by personnel. The controller performs the following control functions. Obtain an operation signal indicating the operation of the operating device; Control the actuator to cause the machine to operate according to the operation of the operating device; The height of the work machine when the operation of the operating device is terminated is stored as the target height. The actuator is controlled so that even if the attitude of the vehicle body changes, the height of the work machine in the direction of gravity is maintained at the target height.

5. The operating machinery as described in any one of claims 1 to 4, characterized in that, The controller controls the actuator so that the working machine maintains its position in the left and right directions even if the posture of the vehicle body changes.

6. A method for controlling a working machine, the working machine comprising: a vehicle body; a working mechanism movably supported relative to the vehicle body; and an actuator connected to the working mechanism for actuating the working mechanism; the method is characterized in that it comprises: Obtain vehicle attitude data representing the attitude of the vehicle body; Obtain machine attitude data representing the attitude of the machine; Based on the vehicle body posture data and the work machine posture data, calculate the height of the work machine in the gravity direction from the reference point of the vehicle body; The actuator is controlled so that the height of the work machine in the direction of gravity is maintained even if the attitude of the vehicle body changes.

7. The method as described in claim 6, characterized in that, The vehicle body includes: Front wheel; The vehicle frame that supports the front wheels and the work machine; rear wheel; A series drive includes a rear axle that supports the rear wheels and extends in the left-right direction, and a body frame that is oscillating about the rear axle. Even if the vehicle frame swings about the rear axle relative to the series drive, the height of the work machine in the direction of gravity is maintained.

8. The method as described in claim 7, characterized in that, The reference point of the vehicle body is configured on the serial driver.

9. The method as described in claim 6, characterized in that, It also has: Acquire an operation signal indicating that the operating device can be operated by an operator; Control the actuator to cause the machine to operate according to the operation of the operating device; The height of the work machine when the operation of the operating device is terminated is stored as the target height. The actuator is controlled so that even if the attitude of the vehicle body changes, the height of the work machine in the direction of gravity is maintained at the target height.

10. The method as described in any one of claims 6 to 9, characterized in that, It also has: The actuator is controlled so that the position of the work machine in the left and right directions is maintained even if the attitude of the vehicle body changes.

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