CN115702278A

CN115702278A - Working machine

Info

Publication number: CN115702278A
Application number: CN202180039802.1A
Authority: CN
Inventors: 上前健志
Original assignee: Komatsu Ltd
Current assignee: Komatsu Ltd
Priority date: 2020-07-30
Filing date: 2021-05-26
Publication date: 2023-02-14
Also published as: US20230203779A1; JP7478616B2; JP2022025829A; WO2022024528A1

Abstract

The detection accuracy of a device for acquiring the position of a blade is improved. A motor grader (1) is provided with an antenna (60) for receiving satellite positioning signals, which is arranged on the ceiling portion (3R) of a cab (3), a first IMU (61) mounted on the cab (3), a second IMU (62) mounted on a traction rod (40), a rotation angle sensor for detecting the rotation angle of a turning disc (41) relative to the traction rod (40), an inclination angle sensor for detecting the inclination angle of a blade (42) relative to the turning disc (41), and a controller. The controller acquires the position of the blade (42) in the global coordinate system based on the satellite positioning signal received by the antenna (60) and the detection results of the first IMU (61), the second IMU (62), the rotation angle sensor, and the tilt angle sensor.

Description

Working machine

Technical Field

The present disclosure relates to a work machine.

Background

The following technique is disclosed in U.S. patent No. 10428493 (patent document 1): the motor grader includes at least one GNSS (Global Navigation Satellite System) antenna and at least one IMU (Inertial Measurement Unit), calculates the position of the blade based on the Measurement results thereof, and automatically controls the blade based on the calculated blade position.

Prior art documents

Patent document

Patent document 1: specification of U.S. Pat. No. 10428493

Disclosure of Invention

Problems to be solved by the invention

In order to efficiently perform a land preparation work by a motor grader with high quality, it is desirable to acquire the position of the blade with higher accuracy. Therefore, the detection accuracy of various antennas and sensors for acquiring the position of the blade is improved.

The present disclosure provides a work machine capable of improving detection accuracy of a device for acquiring a position of a blade.

Means for solving the problems

According to the present disclosure, a work machine is presented. The work machine includes a vehicle body frame having a front frame and a rear frame rotatably coupled to the front frame. The work machine includes a cab mounted on a vehicle body frame and on which an operator rides, a traction rod coupled to the front frame and capable of swinging relative to the front frame, a turning disc supported by the traction rod and capable of rotating relative to the traction rod, and a blade supported by the turning disc and capable of tilting relative to the turning disc. The work machine includes an antenna for receiving satellite positioning signals disposed on a ceiling portion of a cab, a first sensor mounted on the cab and detecting an inclination of the cab, a second sensor detecting an inclination angle of a drawbar with respect to the cab, a third sensor detecting a rotation angle of a turning disc with respect to the drawbar, and a fourth sensor detecting an inclination angle of a blade with respect to the turning disc. And a work machine controller for acquiring the position of the blade in the global coordinate system based on the satellite positioning signal received by the antenna and the detection results of the first sensor, the second sensor, the third sensor, and the fourth sensor.

Effects of the invention

According to the work machine of the present disclosure, the detection accuracy of the device for acquiring the position of the blade can be improved.

Drawings

Fig. 1 is a perspective view schematically showing the structure of a motor grader according to an embodiment.

Fig. 2 is a side view of the motor grader shown in fig. 1.

Fig. 3 is a diagram for explaining an outline of the configuration of the turning mechanism.

Fig. 4 is a plan view of the motor grader in a state where the front frame is rotated with respect to the rear frame.

Fig. 5 is a perspective view of the motor grader showing the vicinity of the working device in an enlarged manner.

Fig. 6 is a perspective view of the motor grader from a different angle than fig. 5.

Fig. 7 is a block diagram showing a configuration related to acquisition of the position of the blade of the motor grader shown in fig. 1.

Fig. 8 is a flowchart showing a flow of processing for calculating the position of the blade.

Detailed Description

Hereinafter, embodiments will be described with reference to the drawings. In the following description, the same components are denoted by the same reference numerals. Their names and functions are also the same. Therefore, detailed description thereof will not be repeated.

Fig. 1 is a perspective view schematically showing the structure of a motor grader 1 according to the embodiment. Fig. 2 is a side view of the motor grader 1 shown in fig. 1.

As shown in fig. 1 and 2, a motor grader 1 according to the embodiment mainly includes front wheels 11 as travel wheels, rear wheels 12 as travel wheels, a vehicle body frame 2, a cab 3, and a work implement 4. The front wheel 11 has one wheel on each of the left and right sides. The rear wheel 12 has two wheels on each of the left and right sides. In the drawings, the traveling wheels are shown to be constituted by 2 front wheels 11 each having one wheel on one side and 4 rear wheels 12 each having two wheels on one side, but the number and arrangement of the front wheels and the rear wheels are not limited thereto.

Motor grader 1 includes components such as an engine disposed in engine compartment 6. Work implement 4 includes a blade 42. The motor grader 1 can perform work such as soil preparation work, snow removal work, light cutting, material mixing, and the like using the blade 42.

In the following description of the drawings, the direction in which the motor grader 1 travels straight will be referred to as the front-rear direction of the motor grader 1. In the front-rear direction of motor grader 1, the side on which front wheels 11 are disposed with respect to work implement 4 is referred to as the front direction. In the front-rear direction of motor grader 1, the side where rear wheels 12 are disposed with respect to work implement 4 is referred to as the rear direction. The left-right direction or the side of the motor grader 1 is a direction orthogonal to the front-rear direction in a plan view. The right and left sides of the left-right direction when viewed from the front direction are the right and left directions, respectively. The vertical direction of the motor grader 1 is a direction orthogonal to a plane defined by the front-rear direction and the left-right direction. In the up-down direction, the side where the ground is located is the lower side, and the side where the sky is located is the upper side.

In the drawings, an arrow X indicates a front-rear direction, an arrow Y indicates a left-right direction, and an arrow Z indicates a vertical direction.

The vehicle body frame 2 shown in fig. 1 and 2 extends in the front-rear direction. The vehicle body frame 2 includes a rear frame 21 and a front frame 22. The rear frame 21 is disposed rearward of the front frame 22. Rear frame 21 supports components such as exterior cover 25 and an engine disposed in engine compartment 6. Exterior cover 25 covers engine compartment 6. The rear wheels 12 of, for example, two wheels on one side are rotatably attached to the rear frame 21 so as to be driven by the driving force from the engine.

The front frame 22 is disposed in front of the rear frame 21. The rear end of the front frame 22 is coupled to the front end of the rear frame 21. The rear frame 21 is rotatably coupled to the front frame 22. The front wheel 11, for example, one wheel on one side, is rotatably attached to the front frame 22.

A counterweight 51 is attached to the front end of the vehicle body frame 2. The counterweight 51 is an example of a fitting attached to the front frame 22. Counterweight 51 is fitted to front frame 22 to increase the downward load carried by front wheels 11, thereby enabling steering and increasing the pressing load of blade 42.

The motor grader 1 can perform an articulated action of rotating the front frame 22 relative to the rear frame 21. The motor grader 1 includes a turning mechanism for performing an articulated operation. Fig. 3 is a diagram for explaining an outline of the configuration of the turning mechanism.

As shown in fig. 3, the front frame 22 and the rear frame 21 are coupled by a coupling shaft 53. The coupling shaft 53 extends in the vertical direction (vertical direction to the paper in fig. 3). The connecting shaft 53 is disposed below the cab 3 (not shown in fig. 3).

The coupling shaft 53 couples the front frame 22 to the rear frame 21 to be rotatable with respect to the rear frame 21. The front frame 22 is rotatable about the connecting shaft 53 in two directions with respect to the rear frame 21. The angle of the front frame 22 with respect to the rear frame 21 can be adjusted. Fig. 4 is a plan view of the motor grader 1 in a state where the front frame 22 is rotated with respect to the rear frame 21. Fig. 4 illustrates a state in which the front frame 22 is rotated in the right direction with respect to the rear frame 21.

The center line CL shown in fig. 2 indicates the center of rotation (hinge center) of the front frame 22 with respect to the rear frame 21. The center line CL is a straight line extending in the vertical direction and passing through the center of the connecting shaft 53. In fig. 3 and 4, the center line CL is a straight line passing through the center of the connecting shaft 53 and extending in the direction perpendicular to the paper surface.

The front frame 22 is pivoted relative to the rear frame 21 by extending and contracting a hinge cylinder 54 connected between the front frame 22 and the rear frame 21 by an operation from the cab 3. An angle sensor 58 is attached to the rear frame 21, and detects a pivot angle, i.e., a hinge angle, of the front frame 22 with respect to the rear frame 21.

By rotating (hinging) the front frame 22 with respect to the rear frame 21, the turning radius of the motor grader 1 during turning can be further reduced, and trenching and normal cutting work by offset running can be performed. The offset travel is a travel in which the motor grader 1 travels straight by setting the direction in which the front frame 22 is turned with respect to the rear frame 21 and the direction in which the front wheels 11 are turned with respect to the front frame 22 to be opposite directions.

Returning to fig. 1 and 2, cab 3 is mounted on front frame 22. Cab 3 has an indoor space for an operator to board, and is disposed at the rear end of front frame 22. The cab 3 may be mounted on the rear frame 21.

An operator's seat 31 on which an operator riding in cab 3 sits is disposed inside cab 3. The operator's seat 31 is disposed substantially at the center of the cab 3 in the front-rear direction and the left-right direction. The cab 3 includes a ceiling portion 3R covering the operator's seat 31 from above, and a plurality of pillars supporting the ceiling portion 3R. The ceiling portion 3R is disposed above the driver seat 31. Each pillar is coupled to a floor portion and a ceiling portion 3R of cab 3.

The cab 3 has a high rigidity configuration suitable for a ROPS (protection against tip-over configuration) standardized to ISO3471 and a FOPS (falling object protection configuration) standardized to ISO 3449. Deformation of cab 3 is effectively suppressed so as to protect the operator riding on cab 3 even when the operator rolls over or a falling object flies into cab 3.

A steering wheel 33 for an operator to turn the motor grader 1 is disposed in front of the operator's seat 31 of the cab 3. The steering wheel 33 is attached to a steering console 34 and supported by the steering console 34. By operating the steering wheel 33 to change the orientation of the front wheels 11, the motor grader 1 can change the traveling direction. In the cab 3, operation portions such as a shift lever, an operation lever of the work implement 4, a brake, and an accelerator pedal are provided.

An antenna 60 for receiving satellite positioning signals is disposed on the ceiling portion 3R of the cab 3. The antenna 60 protrudes upward from the ceiling portion 3R. The antenna 60 is attached to the ceiling portion 3R that is the highest position in the vertical direction in the motor grader 1 in the state where the blade 42 is not erected, and is disposed above the ceiling portion 3R.

A first Inertial Measurement Unit (IMU) 61 is also mounted on the cab 3. The first IMU61 is disposed in a ceiling portion of the indoor space of the cab 3. The first IMU61 is disposed directly below the antenna 60. The antenna 60 and the first IMU61 are disposed at positions overlapping each other when the motor grader 1 is viewed from above.

The antenna 60 and the first IMU61 are disposed at the front edge portion of the cab 3. The antenna 60 and the first IMU61 are disposed in front of the driver seat 31. The antenna 60 and the first IMU61 are disposed directly above the steering console 34. The steering console 34, the antenna 60, and the first IMU61 are disposed at positions overlapping each other when the motor grader 1 is viewed from above. The antenna 60 and the first IMU61 are disposed forward of a center line CL that is a center of rotation of the front frame 22 with respect to the rear frame 21.

The work implement 4 mainly includes a drawbar 40, a turning disc 41, a dozer blade 42, a turning motor 49, and various cylinders 44 to 48. Fig. 5 is a perspective view of the motor grader 1 showing the vicinity of the working device 4 in an enlarged manner. Fig. 6 is a perspective view of the motor grader 1 viewed from a different angle than fig. 5.

Traction rod 40 is disposed below front frame 22. The front end of drawbar 40 is swingably coupled to the front end of front frame 22 using a ball shaft 402. The rear end of the drawbar 40 is supported by the front frame 22 via a pair of

lift cylinders

44, 45. The lower ends of the piston rods of the

lift cylinders

44, 45 are attached to the drawbar 40. The rear end of drawbar 40 can be raised and lowered with respect to front frame 22 by synchronized extension and retraction of a pair of

lift cylinders

44 and 45. The drawbar 40 can swing up and down about an axis along the vehicle traveling direction by different expansion and contraction of the

lift cylinders

44 and 45.

A drawbar shift cylinder 46 is mounted to the side ends of the front frame 22 and the drawbar 40. The rear end of the drawbar 40 can be moved leftward and rightward with respect to the front frame 22 by the extension and contraction of the drawbar shift cylinder 46.

The turn plate 41 is disposed below the front frame 22. The turning disc 41 is disposed below the draw bar 40. A turning disc 41 is supported by the rear end of the drawbar 40. The rotary motor 49 is, for example, a hydraulic motor. The turning disc 41 is driven by a turning motor 49 so as to be turnable in a clockwise direction or a counterclockwise direction as viewed from above the vehicle with respect to the drawbar 40. The turning disc 41 can relatively rotate with respect to the drawbar 40. The tilt angle of the blade 42 with respect to the front frame 22 in a plan view is adjusted by the rotational driving of the rotating disk 41.

A rotary joint 43 is disposed at the rotation center of the rotary disk 41. Hydraulic pressure is supplied from the drawbar 40 to the swivel plate 41 via the swivel joint 43.

The blade 42 is supported by the turn plate 41. Blade 42 is supported by front frame 22 via a turning disc 41 and a drawbar 40.

The blade displacement cylinder 47 is attached to the turning plate 41 and the blade 42, and is disposed along the longitudinal direction of the blade 42. The blade shift cylinder 47 allows the blade 42 to move in the longitudinal direction of the blade 42 with respect to the turn plate 41.

Tilt cylinder 48 is attached to rotating disk 41 and blade 42. By extending and contracting the tilt cylinder 48, the blade 42 swings about an axis extending in the longitudinal direction of the blade 42 with respect to the turn plate 41, and the orientation can be changed in the vertical direction. Tilt cylinder 48 can change the tilt angle of blade 42 with respect to the vehicle traveling direction.

As described above, the blade 42 is configured to be capable of moving up and down with respect to the vehicle, swinging about an axis along the vehicle traveling direction, changing the inclination angle with respect to the front-rear direction, moving in the longitudinal direction of the blade 42, and swinging about an axis extending in the longitudinal direction of the blade 42, via the traction rod 40 and the turning disc 41.

A second Inertia Measurement Unit (IMU) 62 is mounted on the drawbar 40. A rotation angle sensor for detecting a rotation angle of the turning disc 41 with respect to the drawbar 40 is disposed at the turning joint 43. A stroke sensor for detecting the cylinder length of the drawbar shift cylinder 46 is attached to the drawbar shift cylinder 46. A stroke sensor for detecting the cylinder length of the blade shift cylinder 47 is attached to the blade shift cylinder 47. A stroke sensor for detecting the cylinder length of the tilt cylinder 48 is attached to the tilt cylinder 48.

Fig. 7 is a block diagram showing a configuration related to the acquisition of the position of the blade 42 of the motor grader 1 shown in fig. 1. As shown in fig. 7, the motor grader 1 has a controller 70. The controller 70 is, for example, a main controller that controls the entire motor grader 1, and includes a CPU (Central Processing Unit), a nonvolatile memory, a timer, and the like.

The antenna 60 receives radio waves (GNSS radio waves) from satellites, and outputs a signal corresponding to the received radio waves to the controller 70.

The first IMU61 detects the tilt of the cab 3. The first IMU61 detects inclination angles of the cab 3 with respect to the front-rear direction, the left-right direction, and the up-down direction. In the case of the configuration of the embodiment in which the cab 3 is mounted on the front frame 22, the first IMU61 can also be said to detect the inclination angles of the vehicle body frame 2 (front frame 22) with respect to the front-rear direction, the left-right direction, and the up-down direction. The first IMU61 outputs the detection result of the tilt of the cab 3 to the controller 70. The first IMU61 mounted on the cab 3 corresponds to a first sensor of the embodiment that detects the inclination of the cab 3.

The second IMU62 detects the tilt of the tow bar 40. The second IMU62 detects the inclination angles of the drawbar 40 with respect to the front-rear direction, the left-right direction, and the up-down direction. The second IMU62 outputs the detection result of the angle of inclination of the drawbar 40 to the controller 70. The tilt angle of drawbar 40 with respect to cab 3 is detected based on the detection result of first IMU61 and the detection result of second IMU 62. The second IMU62 corresponds to a second sensor of the embodiment that detects the tilt angle of the tow bar 40 with respect to the cab 3.

The blade tilt stroke sensor 63 is a stroke sensor attached to the tilt cylinder 48. The blade tilt stroke sensor 63 detects the cylinder length of the tilt cylinder 48. The blade tilt stroke sensor 63 outputs the detection result of the cylinder length of the tilt cylinder 48 to the controller 70. The inclination angle of the blade 42 with respect to the turning disc 41 is determined based on the cylinder length of the tilt cylinder 48 detected by the blade tilt stroke sensor 63. The blade tilt stroke sensor 63 corresponds to a fourth sensor of the embodiment that detects the inclination angle of the blade 42 with respect to the turn plate 41.

A disc rotation sensor 64 is mounted on the swivel joint 43. The disc rotation sensor 64 corresponds to a third sensor of the embodiment for detecting the rotation angle of the rotating disc 41 with respect to the drawbar 40. The disk rotation sensor 64 outputs the detection result of the rotation angle of the rotating disk 41 to the controller 70.

Blade displacement stroke sensor 65 is a stroke sensor attached to blade displacement cylinder 47. Blade displacement stroke sensor 65 detects the cylinder length of blade displacement cylinder 47. The blade shift stroke sensor 65 outputs the detection result of the cylinder length of the blade shift cylinder 47 to the controller 70. The amount of movement of the blade 42 relative to the turn plate 41 in the longitudinal direction of the blade 42 is determined based on the cylinder length of the blade shift cylinder 47 detected by the blade shift cylinder 47.

The controller 70 includes a storage unit 72, a global coordinate calculation unit 74, a detection information acquisition unit 76, and a blade position calculation unit 78.

The storage unit 72 stores programs for controlling various operations of the motor grader 1. The controller 70 executes various processes for controlling the operation of the motor grader 1 based on a program stored in the storage section 72. The storage unit 72 is a nonvolatile memory and is provided as an area for storing necessary data.

The storage unit 72 stores a relative position (hereinafter, referred to as a traction rod attachment unit reference position) of a two-point position (P1 and P2. Refer to fig. 1 and 5) of a traction rod attachment unit, which is a base position of a cylinder to which the left and

right lift cylinders

44 and 45 are attached to the traction rod 40, with respect to the first IMU61 when the position of the traction rod 40 with respect to the front frame 22 is a neutral position. The storage unit 72 stores relative positions of two points at both ends of the lower edge of the blade 42 (P1, P12, see fig. 1, 5, and 6) with respect to two points P1 and P2 of the traction rod mounting portion (hereinafter, referred to as blade both-end reference positions) when the position of the turning disc 41 with respect to the traction rod 40 is a neutral position, the position of the blade 42 inclined with respect to the turning disc 41 is a neutral position, and the position of the blade 42 reciprocating with respect to the turning disc 41 in the longitudinal direction of the blade 42 is a neutral position.

The global coordinate calculation unit 74 calculates the current position of the antenna 60 in the global coordinate system based on the satellite positioning signal input via the antenna 60. The global coordinate system is a three-dimensional coordinate system with the earth as a reference, which is expressed by latitude, longitude, and altitude. The absolute position of the antenna 60 in the global coordinate system is defined by the coordinate data of the latitude, longitude, and altitude of the antenna 60.

The detection information acquiring unit 76 acquires information detected by each of the first IMU61, the second IMU62, the blade tilt stroke sensor 63, the disk rotation sensor 64, and the blade displacement stroke sensor 65. The detection information acquiring unit 76 acquires the tilt of the cab 3, the tilt of the drawbar 40, the cylinder length of the tilt cylinder 48, the rotation angle of the turn plate 41, and the cylinder length of the blade shift cylinder 47.

The blade position calculating unit 78 calculates the position of the blade 42 in the global coordinate system based on the position of the antenna 60 in the global coordinate system calculated by the global coordinate calculating unit 74 and the information acquired by the detection information acquiring unit 76.

Fig. 8 is a flowchart showing a flow of processing for calculating the position of blade 42. A method of determining the position of the blade 42 in the global coordinate system will be described with reference to fig. 8.

In step S1, the current position of the antenna 60 in the global coordinate system is calculated. The global coordinate calculation unit 74 calculates coordinate data of the latitude, longitude, and altitude of the antenna 60 based on the satellite positioning signal input via the antenna 60.

In step S2, the current position in the global coordinate system of the first IMU61 is calculated. Both the antenna 60 and the first IMU61 are mounted on the cab 3. The relative position of the antenna 60 to the first IMU61 is constant regardless of the motion of the motor grader 1. Therefore, the current position of the first IMU61 in the global coordinate system is obtained by an operation based on the current position of the antenna 60 in the global coordinate system and the relative positions of the antenna 60 and the first IMU61.

In step S3, detection information of each sensor is acquired. The detection information acquiring unit 76 acquires the detection information of the tilt of the cab 3 from the first IMU61. The detection information acquiring unit 76 acquires detection information of the inclination of the drawbar 40 from the second IMU 62. The detection information acquiring unit 76 acquires detection information of the cylinder length of the tilt cylinder 48 from the blade tilt stroke sensor 63. The detection information acquiring unit 76 acquires detection information of the rotation angle of the rotating disk 41 from the disk rotation sensor 64. The detection information acquiring unit 76 acquires detection information of the cylinder length of the blade displacement cylinder 47 from the blade displacement stroke sensor 65.

In step S4, the current relative positions of the two points P1 and P2 of the drawbar mounting part with respect to the first IMU61 are calculated.

The blade position calculating unit 78 acquires information of the detection result of the first IMU61 and the detection result of the second IMU62 from the detection information acquiring unit 76. Blade position calculating unit 78 calculates the current tilt angle of traction rod 40 with respect to cab 3 based on the tilt angles of cab 3 with respect to the front-rear direction, the left-right direction, and the up-down direction, and the tilt angles of traction rod 40 with respect to the front-rear direction, the left-right direction, and the up-down direction.

In order to detect the tilt angle of the tow bar 40 with respect to the cab 3 with higher accuracy, the cylinder length of the tow bar shift cylinder 46 detected by a stroke sensor attached to the tow bar shift cylinder 46 may be used in addition to the detection results of the first IMU61 and the second IMU 62.

The blade position calculating unit 78 obtains the current relative positions of the two-point positions P1 and P2 of the traction rod attachment portion with respect to the first IMU61 by calculation based on the reference position of the traction rod attachment portion read from the storage unit 72 and the current inclination angle of the traction rod 40 with respect to the cab 3.

In step S5, the current relative positions of two point positions P11 and P12 at both ends of the lower edge of the blade with respect to two point positions P1 and P2 of the drawbar mounting portion are calculated.

Blade position calculating unit 78 receives information of the detection result of disk rotation sensor 64 from detection information acquiring unit 76. The blade position calculating unit 78 obtains the rotation angle of the turning disc 41 with respect to the drawbar 40. The blade 42 rotates relative to the drawbar 40 integrally with the turn plate 41. Blade position calculating unit 78 obtains the rotation angle of blade 42 with respect to traction rod 40.

The blade position calculating unit 78 receives information of the detection result of the cylinder length of the tilt cylinder 48 from the detection information acquiring unit 76. The blade position calculating unit 78 obtains the inclination angle of the blade 42 with respect to the turn plate 41.

The blade position calculating unit 78 receives information of the result of detection of the cylinder length of the blade shift cylinder 47 from the detection information acquiring unit 76. Blade position calculating unit 78 obtains the amount of movement of blade 42 relative to turning disc 41 in the longitudinal direction of blade 42.

The blade position calculating unit 78 obtains the current relative positions of the two-point positions P11 and P12 of the two ends of the lower edge of the blade with respect to the two-point positions P1 and P2 of the traction rod mounting portion by calculation based on the blade both-end reference positions read from the storage unit 72, the current rotation angle of the blade 42 with respect to the traction rod 40, the current inclination angle of the blade 42 with respect to the turn plate 41, and the current amount of movement of the blade 42 with respect to the turn plate 41 in the longitudinal direction of the blade 42.

In step S6, the blade position calculating unit 78 obtains the current positions of the two points P1 and P2 of the blade attachment portion in the global coordinate system by calculating the current position of the first IMU61 in the global coordinate system and the current relative positions of the two points P1 and P2 of the first IMU61 and the traction rod attachment portion. The blade position calculating section 78 obtains the current positions of two point positions P11 and P12 on both ends of the lower edge of the blade in the global coordinate system by calculating the current position of the first IMU61 in the global coordinate system, the current relative positions of the two point positions P1 and P2 on the drawbar mounting portion with respect to the first IMU61, and the current relative positions of the two point positions P11 and P12 on both ends of the lower edge of the blade with respect to the two point positions P1 and P2 on the drawbar mounting portion. The blade position calculating section 78 obtains the current vertical position of a straight line connecting two point positions P11 and P12 at both ends of the lower edge of the blade in the global coordinate system.

The position of the lower edge of the blade 42 in the global coordinate system obtained as described above can be used for automatic control of the motor grader 1. For example, during the land leveling work, the motor grader 1 can be driven by controlling the blade 42 so that the vertical position of the lower edge of the blade 42 coincides with the design surface. In the shaping work of the normal surface, the motor grader 1 can be controlled to travel by controlling the blade 42 so that either one of two point positions P11 and P12 on the lower edge of the blade coincides with the toe of the design topography. By performing automatic control in this manner, the motor grader 1 can perform efficient and high-quality work.

Although some descriptions overlap with the above description, if a characteristic configuration and an operation effect of the present embodiment are collectively described, the following description will be made.

As shown in fig. 2, the motor grader 1 according to the embodiment includes an antenna 60 for receiving satellite positioning signals disposed in the ceiling portion 3R of the cab 3, and a first IMU61 mounted on the cab 3.

Since the antenna 60 is disposed on the ceiling portion 3R of the cab 3, which is the highest position in the vehicle body of the motor grader 1, the influence of surrounding obstacles is reduced, and therefore the antenna 60 can easily capture a satellite positioning signal. Since both the antenna 60 and the first IMU61 are disposed in the highly rigid cab 3, an error between the position of the antenna 60 and the position of the first IMU61 due to the bending of the vehicle body is reduced. The antenna 60 and the first IMU61 are disposed at close positions. Thus, the current position of the first IMU61 in the global coordinate system can be acquired with high accuracy based on the current position of the antenna 60 in the global coordinate system and the current relative position of the first IMU61 with respect to the antenna 60.

Therefore, the current positions of the two point positions P11 and P12 on the lower edge of the blade in the global coordinate system can be accurately obtained based on the current position of the first IMU61 in the global coordinate system and the current relative positions of the two point positions P11 and P12 on the lower edge of the blade with respect to the first IMU61.

As shown in fig. 2, the first IMU61 is disposed in a ceiling portion of the indoor space of the cab 3. By disposing in this manner, the first IMU61 can be reliably disposed at a position close to the antenna 60 disposed in the ceiling portion 3R.

As shown in fig. 2, the first IMU61 is disposed directly below the antenna 60. By disposing in this manner, the first IMU61 can be disposed closer to the antenna 60.

As shown in fig. 2, the first IMU61 is disposed at the front edge portion of the cab 3. By disposing the first IMU61 at the front edge portion, which is a position close to the blade 42 in the cab 3, it is possible to reduce an error in the relative positions of the two point positions P11 and P12 at both ends of the lower edge of the blade with respect to the first IMU61 due to the deflection of the vehicle body. Therefore, the current positions of two point positions P11 and P12 at both ends of the lower edge of the blade in the global coordinate system can be acquired with higher accuracy. Further, since a wide indoor space can be secured in the cab 3, the degree of freedom in the arrangement of elements such as the operator's seat 31 provided in the cab 3 can be improved, and the riding quality and workability of the operator riding in the cab 3 can be improved.

As shown in fig. 2, the first IMU61 is disposed in front of the operator's seat 31 in the cab 3. This enables the first IMU61 to be reliably disposed at the front edge portion of the cab 3.

As shown in fig. 2, the first IMU61 is disposed directly above the steering console 34. This enables the first IMU61 to be reliably disposed at the front edge portion of the cab 3.

As shown in fig. 2, the cab 3 is mounted on the front frame 22. When the cab 3 is mounted on the rear frame 21, the hinge angle needs to be corrected in order to obtain the relative positions of the two point positions P11 and P12 on the lower edge of the blade with respect to the first IMU61 mounted on the cab 3. If the cab 3 is mounted on the front frame 22, the correction of the hinge angle is not necessary, and the error associated with the correction can be reduced. Therefore, the current positions of two point positions P11 and P12 at both ends of the lower edge of the blade in the global coordinate system can be acquired with higher accuracy.

As shown in fig. 2, the first IMU61 is disposed forward of a center line CL, which is a center of rotation of the front frame 22 with respect to the rear frame 21. By disposing the first IMU61 in this manner, the first IMU61 can be reliably disposed near the front edge portion of the cab 3 of the blade 42.

In the description of the embodiment, an example in which the detection results of the blade tilt stroke sensor 63, the disc rotation sensor 64, and the blade shift stroke sensor 65 are used to obtain the relative positions of the two-point positions P11 and P12 at the two ends of the lower edge of the blade with respect to the two-point positions P1 and P2 of the drawbar mounting portion is described. It is not necessary to provide blade displacement stroke sensor 65 in blade displacement cylinder 47. The position of the blade 42 may be automatically controlled on the assumption that the position of the blade 42 with respect to the turning plate 41 in the longitudinal direction of the blade 42 is a neutral position. The operator may manually turn the motor grader 1 while observing the position of the blade 42. The turning operation of the motor grader 1 may be automatically controlled, and in this case, a rotation sensor for detecting the steering angle of the front wheels 11 may be additionally provided.

Instead of the first IMU61 and the second IMU62, an attitude and orientation reference device may be used. By attaching an attitude and heading reference device capable of measuring a yaw angle to cab 3 and traction rod 40, respectively, the amount of displacement of traction rod 40 in the left-right direction with respect to front frame 22 (with respect to cab 3) can be clearly detected. Since it is not necessary to additionally use the cylinder length of the drawbar shift cylinder 46 in order to improve the detection accuracy of the inclination angle of the drawbar 40 with respect to the cab 3, and it is not necessary to provide a stroke sensor to the drawbar shift cylinder 46, the configuration can be simplified.

The sensor for obtaining the inclination angle of blade 42 with respect to turntable 41 is not limited to blade tilt stroke sensor 63. Instead of the blade tilt stroke sensor 63, a third IMU, a tilt sensor, or the like may be attached to the blade 42, and the tilt angle of the blade 42 with respect to the turntable 41 may be obtained based on the detection result of the second IMU62 and the detection result of the third IMU, the tilt sensor, or the like.

A plurality of antennas 60, first IMU61, and second IMU62 may be provided. By using the detection results of the plurality of antennas and the plurality of IMUs, the position of blade 42 in the global coordinate system can be determined with higher accuracy. In addition, the reliability of the structure for specifying the position of the blade 42 in the global coordinate system can be improved.

In order to obtain the vertical position of the lower edge of the blade 42 in the global coordinate system, two points on the lower edge of the blade 42 that are different from the two-point positions P11 and P12 on the both ends of the lower edge of the blade may be used. For example, two points of the lower edge of the blade 42, the center position and the end position of the blade 42 in the longitudinal direction, may be detected. If two point positions P11, P12 at both ends of the blade lower edge are used, the distance between the two points becomes maximum, and the accuracy of detecting the position of the blade 42 can be improved.

Antenna 60 need not protrude upward from the ceiling surface of cab 3. Antenna 60 may be embedded in ceiling portion 3R of cab 3. By shielding the antenna 60, it is possible to suppress a reduction in the detection accuracy of the antenna 60 due to an obstacle colliding with the antenna 60.

Antenna 60 may be disposed at a position other than the front edge portion of cab 3. For example, the antenna 60 may be disposed at the rear edge of the cab 3. The first IMU61 may be disposed at a position other than the ceiling portion of the cab 3. The first IMU61 may be disposed at a position other than the front edge portion of the cab 3. For example, the first IMU61 may be disposed behind the driver seat 31.

It should be understood that the embodiments disclosed herein are illustrative and not restrictive in all respects. The scope of the present invention is defined by the claims rather than the description above, and all changes that come within the meaning and range of equivalency of the claims are intended to be embraced therein.

Description of reference numerals:

1 \ 8230a motor grader; 2 \ 8230and a vehicle body frame; a cab; a ceiling portion; 4\8230aworking device; 11 8230and a front wheel; 12 \ 8230and a rear wheel; 21 \ 8230and a rear frame; 22\8230afront frame; 31\8230adriver seat; 33 \ 8230a steering wheel; 34 \ 8230and a steering console; 40\8230adraw bar; 41 8230a rotary disc; 42\8230anda dozer blade; 43 8230a rotary joint; 44. 45 8230and a lifting cylinder; 46 8230a tow bar shift cylinder; 47\8230adozer blade shift cylinder; 48 \ 8230and a tilting cylinder; 49 8230a rotary motor; 53 \ 8230and connecting shaft; 54 \ 8230a hinged cylinder; 58 \ 8230and angle sensor; 60 \ 8230and antenna; 61\8230firstinertia measuring device; 62 \ 8230and a second inertia measuring device; 63 \ 8230and a tilt stroke sensor of the dozer blade; 64 \ 8230a tow bar displacement travel sensor; 65 \ 8230disc rotation sensor; 66 \ 8230, a sensor for the displacement stroke of the blade; 70 8230a controller; a storage portion; a global coordinate operation section; a detection information acquisition unit; a blade position calculating section; 402 \ 8230and a ball shaft part; cl.

Claims

1. A working machine, wherein,

the work machine is provided with:

a vehicle body frame having a front frame and a rear frame rotatably coupled to the front frame;

a cab mounted on the vehicle body frame and on which an operator rides;

a drawbar coupled to the front frame and swingable with respect to the front frame;

a rotary disc supported by the drawbar and capable of rotating relative to the drawbar;

a blade supported by the turning disc and tiltable with respect to the turning disc;

an antenna for receiving satellite positioning signals, which is disposed on the ceiling portion of the cab;

a first sensor mounted on the cab and detecting a tilt of the cab;

a second sensor that detects an inclination angle of the drawbar with respect to the cab;

a third sensor that detects a rotation angle of the turn disc with respect to the drawbar;

a fourth sensor that detects an inclination angle of the blade with respect to the turn plate; and

and a controller that acquires a position of the blade in a global coordinate system based on a satellite positioning signal received by the antenna and detection results of the first sensor, the second sensor, the third sensor, and the fourth sensor.

2. The work machine of claim 1,

the first sensor is disposed in a ceiling portion of the cab.

3. The work machine according to claim 1 or 2,

the first sensor is disposed directly below the antenna.

4. The work machine according to any one of claims 1 to 3,

the first sensor is disposed at a front edge portion of the cab.

5. The work machine of claim 4,

the cab has a driver seat for an operator to sit on,

the first sensor is disposed in front of the driver seat.

6. The work machine according to claim 4 or 5,

the cab has a steering wheel for an operator to turn the work machine, and a steering console supporting the steering wheel,

the first sensor is disposed directly above the steering console.

7. The work machine according to any one of claims 1 to 6,

the cab is mounted on the front frame.

8. The work machine of claim 7,

the first sensor is disposed forward of a center of rotation of the front frame with respect to the rear frame.