CONTROL SYSTEM FOR WORK MACHINE AND CONTROL METHOD FOR WORK MACHINE

FIELD

[0001]The present disclosure relates to a control system for a work machine and a control method for a work machine.

BACKGROUND

[0002]In the technical field related to work machines, work vehicles such as those disclosed in Patent Literature 1 are known. In addition, work machines including object detection devices that detect obstacles, such as those disclosed in Patent Literature 2, are known.

CITATION LIST

Patent Literature

SUMMARY

Technical Problem

[0005]In a work site such as a mine, cliffs may be present. Cliffs include ascending cliffs and descending cliffs. If the traveling stop control of the work machine is performed without considering the type of cliff, it may be difficult to appropriately stop the travel of the work machine.

[0006]An object of the present disclosure is to appropriately stop travel of a work machine.

Solution to Problem

[0007]In order to achieve an aspect of the present invention, a control system for a work machine including a vehicle body, a traveling device that travels while supporting the vehicle body, and an excavation blade of an excavation working equipment disposed in front of the vehicle body, the control system comprises: a detection data acquisition unit that acquires detection data of a sensor that detects surroundings of the work machine; a determination unit that determines whether or not there is a descending cliff in front of the work machine on a basis of the detection data of the sensor; and a traveling control unit that controls the traveling device on a basis of a relative position between a forward stop position set behind the excavation blade and the descending cliff in a case where it is determined that there is the descending cliff.

Advantageous Effects of Invention

[0008]According to the present disclosure, travel of a work machine can be appropriately stopped.

BRIEF DESCRIPTION OF DRAWINGS

[0009]FIG. 1 is a diagram schematically illustrating a management system of a work site according to an embodiment.

[0010]FIG. 2 is a side view schematically illustrating a work machine according to the embodiment.

[0011]FIG. 3 is a plan view schematically illustrating a three-dimensional sensor and an obstacle sensor according to the embodiment.

[0012]FIG. 4 is a diagram schematically illustrating an example of an operation of the work machine according to the embodiment.

[0013]FIG. 5 is a block diagram illustrating a detection system for the work machine according to the embodiment.

[0014]FIG. 6 is a diagram for explaining storage data stored in a current terrain data storage unit according to the embodiment.

[0015]FIG. 7 is a plan view schematically illustrating an alarm range and a stop range set in the work machine according to the embodiment.

[0016]FIG. 8 is a side view schematically illustrating an alarm range and a stop range set in the work machine according to the embodiment.

[0017]FIG. 9 is a plan view schematically illustrating an alarm range and a stop range set in the work machine according to the embodiment.

[0018]FIG. 10 is a side view schematically illustrating an alarm range and a stop range set in the work machine according to the embodiment.

[0019]FIG. 11 is a plan view schematically illustrating an alarm range and a stop range set in the work machine according to the embodiment.

[0020]FIG. 12 is a side view schematically illustrating an alarm range and a stop range set in the work machine according to the embodiment.

[0021]FIG. 13 is a plan view schematically illustrating an alarm range and a stop range set in the work machine according to the embodiment.

[0022]FIG. 14 is a side view schematically illustrating an alarm range and a stop range set in the work machine according to the embodiment.

[0023]FIG. 15 is a plan view schematically illustrating an alarm range and a stop range set in the work machine according to the embodiment.

[0024]FIG. 16 is a side view schematically illustrating an alarm range and a stop range set in the work machine according to the embodiment.

[0025]FIG. 17 is a flowchart illustrating a control method for the work machine according to the embodiment.

[0026]FIG. 18 is a block diagram illustrating a computer system according to the embodiment.

DESCRIPTION OF EMBODIMENTS

[0027]Hereinafter, embodiments according to the present disclosure will be described with reference to the drawings, but the present disclosure is not limited to the embodiments. The components of the embodiments described below can be appropriately combined. In addition, some components may not be used.

Management System

[0028]FIG. 1 is a diagram schematically illustrating a management system 1 of a work site according to an embodiment. In the embodiment, the work site is a mine. The mine refers to a place or business site where minerals are mined. Examples of the mine include a metal mine for mining metal, a non-metal mine for mining limestone, and a coal mine for mining coal. A plurality of work machines 2 operates at a work site. In the embodiment, the work machine 2 is a bulldozer. The work machine 2 performs predetermined work at a work site. Examples of the work performed by the work machine 2 include excavating work, pushing work, and leveling work.

[0029]The management system 1 includes a management device 3 and a communication system 4. The management device 3 includes a computer system. The management device 3 is disposed outside the work machine 2. The management device 3 is installed in a control facility 5 of the work site. The management device 3 manages the work site and the work machine 2. Administrators are present in the control facility 5. Examples of the communication system 4 include the internet, a mobile phone communication network, a satellite communication network, and a local area network (LAN). Wi-Fi (registered trademark), which is one standard of wireless LAN, is exemplified as the local area network.

[0030]The work machine 2 includes a control device 6 and a wireless communication device 4A. The control device 6 includes a computer system. The wireless communication device 4A is connected to the control device 6. The communication system 4 includes the wireless communication device 4A connected to the control device 6 and a wireless communication device 4B connected to the management device 3. The management device 3 and the control device 6 of the work machine 2 wirelessly communicate with each other via the communication system 4.

Work Machine

[0031]FIG. 2 is a side view schematically illustrating the work machine 2 according to the embodiment. As illustrated in FIG. 2, the work machine 2 includes a vehicle body 7, a traveling device 8, an excavation working equipment 9, a ripper working equipment 10, a position sensor 11, an inclination sensor 12, a three-dimensional sensor 13, and an obstacle sensor 14. The vehicle body 7 includes an engine compartment 15. An engine 16 is housed in the engine compartment 15. The engine 16 is a drive source of the work machine 2. The traveling device 8 travels while supporting the vehicle body 7. The traveling device 8 includes a pair of crawler belts 17. As the crawler belt 17 rotates, the work machine 2 travels.

[0032]The excavation working equipment 9 performs excavating work, pushing work, or leveling work of a work target. The excavation working equipment 9 is attached to the vehicle body 7. At least a part of the excavation working equipment 9 is disposed in front of the vehicle body 7. The excavation working equipment 9 includes an excavation blade 18, a lift frame 19, a tilt cylinder 20, and a lift cylinder 21.

[0033]The excavation blade 18 is disposed in front of the vehicle body 7. The excavation blade 18 includes a cutting edge 18A. The lift frame 19 supports the excavation blade 18. One end portion of the lift frame 19 is connected to the back surface of the excavation blade 18 via a pivot mechanism. The other end portion of the lift frame 19 is connected to the vehicle body 7 via a pivot mechanism. Note that the other end portion of the lift frame 19 may be connected to the traveling device 8 via a pivot mechanism.

[0034]Each of the tilt cylinder 20 and lift cylinder 21 operates the excavation blade 18. The tilt cylinder 20 is driven to tilt the excavation blade 18. The lift cylinder 21 is driven to move the excavation blade 18 up and down. One end portion of the tilt cylinder 20 is connected to the back surface of the excavation blade 18 via a pivot mechanism. The other end portion of the tilt cylinder 20 is connected to the upper surface of the lift frame 19. As the tilt cylinder 20 extends and contracts, the tilt angle of the excavation blade 18 changes. One end portion of the lift cylinder 21 is connected to the lift frame 19 via a pivot mechanism. The other end portion of the lift cylinder 21 is connected to the vehicle body 7 via a pivot mechanism. As the lift cylinder 21 expands and contracts, the excavation blade 18 moves in the vertical direction.

[0035]The ripper working equipment 10 performs ripping work including cutting or crushing of the work target. The ripper working equipment 10 is attached to the vehicle body 7. At least a part of the ripper working equipment 10 is disposed behind the vehicle body 7. The ripper working equipment 10 includes a shank 22, a ripper arm 23, a tilt cylinder 24, a lift cylinder 25, and a beam 26. The shank 22 is disposed behind the vehicle body 7. The shank 22 has a ripper point 22A. The ripper point 22A is provided at the tip of the shank 22. The ripper arm 23 supports the shank 22. The ripper arm 23 connects the vehicle body 7 and the shank 22. One end portion of the ripper arm 23 is connected to the rear portion of the vehicle body 7 via a pivot mechanism. The other end portion of the ripper arm 23 is connected to the beam 26. The beam 26 is rotatably connected to the ripper arm 23. The shank 22 is connected to the ripper arm 23 via the beam 26.

[0036]Each of the tilt cylinder 24 and the lift cylinder 25 operates the shank 22. Each of the tilt cylinder 24 and the lift cylinder 25 is connected to the vehicle body 7. The tilt cylinder 24 is driven to tilt the shank 22. The lift cylinder 25 is driven to move the shank 22 up and down. One end portion of the tilt cylinder 24 is connected to the beam 26 via a pivot mechanism. The other end portion of the tilt cylinder 24 is connected to the rear portion of the vehicle body 7. As the tilt cylinder 24 extends and contracts, the tilt angle of the shank 22 changes. The tilt cylinder 24 moves the shank 22 in the front-rear direction. One end portion of the lift cylinder 25 is connected to the beam 26 via a pivot mechanism. The other end portion of the lift cylinder 25 is connected to the rear portion of the vehicle body 7. As the lift cylinder 25 expands and contracts, the shank 22 moves in the vertical direction. The lift cylinder 25 moves the shank 22 in the vertical direction.

[0037]The ripper working equipment 10 pierces the ripper point 22A into the work target. As the traveling device 8 travels in a state where the ripper point 22A is pierced into the work target, the work target is cut or crushed. While the traveling device 8 is traveling, the shank 22 may be moved in the vertical direction and the front-rear direction.

[0038]The position sensor 11 detects the position of the work machine 2. The position of the work machine 2 is detected using a global navigation satellite system (GNSS). The global navigation satellite system includes a global positioning system (GPS). The global navigation satellite system detects a position in a global coordinate system defined by coordinate data of latitude, longitude, and altitude. The global coordinate system refers to a coordinate system fixed to the earth. The position sensor 11 includes a GNSS receiver. The position sensor 11 detects the position of the work machine 2 in the global coordinate system. The position sensor 11 is disposed on the vehicle body 7.

[0039]The inclination sensor 12 detects the inclination of the vehicle body 7. The inclination sensor 12 detects an inclination angle of the vehicle body 7 with respect to a horizontal plane. The inclination sensor 12 includes an inertial measurement unit (IMU). The inclination sensor 12 is disposed on the vehicle body 7.

[0040]The three-dimensional sensor 13 detects a three-dimensional shape of a detection target. The three-dimensional sensor 13 detects the three-dimensional shape of the detection target in a non-contact manner with the detection target. The detection target of the three-dimensional sensor 13 includes a work site. The three-dimensional sensor 13 detects a three-dimensional shape of the work site. The three-dimensional shape of the work site includes the terrain of the work site. The three- dimensional sensor 13 detects the distance to the surface of the detection target. The three-dimensional sensor 13 detects the three-dimensional shape of the surface of the detection target by detecting the relative distance to each of the plurality of detection points on the surface of the detection target. The three-dimensional data indicating the three-dimensional shape of the detection target includes point cloud data including a plurality of detection points. The three-dimensional data includes a relative distance and a relative position between the three-dimensional sensor 13 and each of the plurality of detection points defined in the detection target. The three-dimensional data includes height data of each of the plurality of detection points. As the three-dimensional sensor 13, a laser sensor (light detection and ranging (LIDAR)) that detects a detection target by emitting laser light is exemplified. Note that the three-dimensional sensor 13 may be a three-dimensional camera such as a stereo camera. The three-dimensional sensor 13 is disposed on the vehicle body 7.

[0041]The obstacle sensor 14 detects an object present around the work machine 2. The obstacle sensor 14 detects an obstacle of the work machine 2 present at the work site. The obstacle sensor 14 detects an obstacle in a non-contact manner with the obstacle. As the obstacle sensor 14, a radar sensor (radio detection and ranging (RADAR)) that detects an obstacle by emitting radio waves is exemplified. Note that obstacle sensor 14 may be an infrared sensor that detects an obstacle by emitting infrared light. The obstacle sensor 14 is disposed on the vehicle body 7.

[0042]FIG. 3 is a plan view schematically illustrating the three-dimensional sensor 13 and the obstacle sensor 14 according to the embodiment. As illustrated in FIG. 3, the three-dimensional sensor 13 has a detection range 130. The three-dimensional sensor 13 detects three-dimensional data of a detection target disposed in the detection range 130. In the embodiment, the three-dimensional sensor 13 includes a three-dimensional sensor 13F that detects three-dimensional data in front of the vehicle body 7 and a three-dimensional sensor 13B that detects three-dimensional data behind the vehicle body 7. The detection range 130 of the three-dimensional sensor 13 includes a detection range 130F of the three-dimensional sensor 13F and a detection range 130B of the three-dimensional sensor 13B. At least a part of the detection range 130F is defined in front of the excavation working equipment 9. At least a part of the detection range 130B is defined behind the ripper working equipment 10.

[0043]As illustrated in FIG. 3, the obstacle sensor 14 has a detection range 140. The obstacle sensor 14 detects an obstacle disposed in the detection range 140. In the embodiment, the obstacle sensor 14 detects an obstacle behind the vehicle body 7. The obstacle sensor 14 includes an obstacle sensor 14L disposed on the left side of the center of the vehicle body 7 in the left-right direction and an obstacle sensor 14R disposed on the right side. The detection range 140 of the obstacle sensor 14 includes a detection range 140L of the obstacle sensor 14L and a detection range 140R of the obstacle sensor 14R. At least a part of the detection range 140L and at least a part of the detection range 140R are defined behind the vehicle body 7. At least a part of the detection range 140L is defined on the left side of the vehicle body 7. At least a part of the detection range 140R is defined on the right side of the vehicle body 7.

Operation of Work Machine

[0044]FIG. 4 is a diagram schematically illustrating an example of the operation of the work machine 2 according to the embodiment. In the embodiment, the work machine 2 can perform slot dozing. The slot dozing refers to a construction method in which the work machine 2 excavates the work target while repeating forward movement and reverse movement along a slot-shaped excavation lane formed in the work target. In the embodiment, the work machine 2 performs slot dozing by automatic control. As illustrated in FIG. 4, the work machine 2 performs slot dozing such that the current terrain has a shape along a final design surface 27Z. In the example illustrated in FIG. 4, in the first excavation, the work machine 2 excavates the work target with the excavation working equipment 9 while moving forward from an excavation start point 27S so that the current terrain has a shape along a first intermediate design surface 27A. After the first excavation is completed, the work machine 2 moves in reverse to return to the excavation start point 27S. In the second excavation, the work machine 2 excavates the work target with the excavation working equipment 9 while moving forward from the excavation start point 27S so that the current terrain has a shape along a second intermediate design surface 27B. The work machine 2 repeats forward movement and reverse movement until the current terrain becomes a shape along the final design surface 27Z.

[0045]Note that the automatic control of the work machine 2 may be semi-automatic control performed in conjunction with manual operation by an operator, or may be fully automatic control performed without manual operation. In the case of the semi-automatic control, an operation device for manual operation may be mounted on the work machine 2 and may be boarded by an operator riding on the work machine 2. An operation device for manual operation may be disposed outside the work machine 2 and remotely operated by an operator present outside the work machine 2.

Control System

[0046]FIG. 5 is a block diagram illustrating a control system 100 for the work machine 2 according to the embodiment. The management system 1 includes the control system 100. The control system 100 performs traveling stop control of the work machine 2. The control system 100 includes the control device 6, the position sensor 11, the inclination sensor 12, the three-dimensional sensor 13, the obstacle sensor 14, an alarm device 30, and the traveling device 8. The control device 6 includes a position data acquisition unit 61, a three-dimensional data acquisition unit 62, an obstacle data acquisition unit 63, a determination unit 64, a position setting unit 65, an alarm control unit 66, a traveling control unit 67, a current terrain data creation unit 68, and a current terrain data storage unit 69.

[0047]The position data acquisition unit 61 acquires position data indicating the current position of the work machine 2. The current position of the work machine 2 includes detection data of the position sensor 11. The position data acquisition unit 61 acquires detection data of the position sensor 11 as position data. The position data acquisition unit 61 acquires posture data indicating the posture of the work machine 2. The posture of the work machine 2 includes detection data of the inclination sensor 12. The position data acquisition unit 61 acquires detection data of the inclination sensor 12 as posture data.

[0048]The three-dimensional data acquisition unit 62 acquires three-dimensional data indicating a three-dimensional shape of a work site where the work machine 2 operates. The three-dimensional data of the work site includes detection data of the three-dimensional sensor 13. The three-dimensional data acquisition unit 62 acquires detection data of the three-dimensional sensor 13 as three-dimensional data. In addition, the three-dimensional sensor 13 detects an object present in the traveling direction of the work machine 2. The three-dimensional data acquisition unit 62 acquires detection data of the three-dimensional sensor 13 that detects an object present in the traveling direction of the work machine 2. In addition, the three-dimensional sensor 13 detects the surroundings of the work machine 2. The three-dimensional data acquisition unit 62 acquires detection data of the three-dimensional sensor 13 that detects the surroundings of the work machine 2.

[0049]The obstacle data acquisition unit 63 acquires obstacle data indicating an obstacle present around the work machine 2. The obstacle data includes detection data of the obstacle sensor 14. The obstacle data acquisition unit 63 acquires detection data of the obstacle sensor 14 as obstacle data. The obstacle data may include three-dimensional data indicating the three-dimensional shape of the detection target of the three-dimensional sensor 13. The obstacle data acquisition unit 63 may acquire, as obstacle data, a position obtained by integrating representative points of standing objects detected from point cloud data included in the three-dimensional data and detection data of the obstacle sensor 14.

[0050]The determination unit 64 determines the type of cliff present in the traveling direction of the work machine 2 on the basis of the detection data of the three-dimensional sensor 13. The three-dimensional sensor 13 detects the three-dimensional shape around the work machine 2. The determination unit 64 determines the type of cliff on the basis of three-dimensional data indicating the three-dimensional shape around the work machine 2 detected by the three-dimensional sensor 13. Types of cliffs include ascending cliffs and descending cliffs. The determination unit 64 determines whether or not there is an ascending cliff in the traveling direction of the work machine 2 on the basis of the detection data of the three-dimensional sensor 13. The determination unit 64 determines whether or not there is a descending cliff in the traveling direction of the work machine 2 on the basis of the detection data of the three-dimensional sensor 13.

[0051]The position setting unit 65 changes the alarm range of the work machine 2 on the basis of the type of cliff determined by the determination unit 64. In addition, the position setting unit 65 changes the stop position of the work machine 2 on the basis of the type of cliff determined by the determination unit 64.

[0052]The alarm control unit 66 controls the alarm device 30 on the basis of the alarm range set by the position setting unit 65. The alarm device 30 is disposed, for example, in a cab of the work machine 2. The alarm device 30 may be an audio output device that outputs an alarm sound or a display device that displays alarm display data.

[0053]The traveling control unit 67 controls the traveling control unit 67 on the basis of the stop position set by the position setting unit 65. The traveling control unit 67 stops the travel of the work machine 2 on the basis of the stop position set by the position setting unit 65.

[0054]The current terrain data creation unit 68 creates the current terrain data of the work site on the basis of the three-dimensional data acquired by the three-dimensional data acquisition unit 62, the position data indicating the current position of the work machine 2 acquired by the position data acquisition unit 61, and the posture data indicating the posture of the work machine 2 acquired by the position data acquisition unit 61. The current terrain data creation unit 68 creates the current terrain data of the work site on the basis of the detection data of the three-dimensional sensor 13, the detection data of the position sensor 11, and the detection data of the inclination sensor 12.

[0055]The current terrain data storage unit 69 stores the current terrain data of the work site created by the current terrain data creation unit 68. The current terrain data storage unit 69 stores current terrain data, time, and attribute data assigned to the current terrain data in association with each other. In addition, the current terrain data storage unit 69 stores the current terrain data, the time when the current terrain data is acquired, and the current position of the work machine 2 where the current terrain data is acquired in association with each other on the basis of the position data indicating the current position of the work machine 2 acquired by the position data acquisition unit 61.

[0056]The management device 3 includes a current terrain data creation unit 3A and a current terrain data storage unit 3B. As described above, there is a plurality of work machines 2 at the work site. Each of the plurality of work machines 2 transmits the current terrain data stored in the current terrain data storage unit 69 to the management device 3 via the communication system 4. The current terrain data creation unit 3A integrates the current terrain data transmitted from each of the plurality of work machines 2 to create the current terrain data of the work site. The current terrain data storage unit 3B stores the current terrain data created by the current terrain data creation unit 3A. Each of the plurality of work machines 2 transmits the current terrain data to the management device 3 at predetermined time intervals. Each of the plurality of work machines 2 transmits current terrain data to the management device 3, for example, every second. The current terrain data creation unit 3A creates current terrain data each time the current terrain data is received. Each time the current terrain data creation unit 3A creates the current terrain data, the current terrain data stored in the current terrain data storage unit 3B is updated.

Storage Data

[0057]FIG. 6 is a diagram for explaining storage data stored in the current terrain data storage unit 69 according to the embodiment. As illustrated in FIG. 6, the three-dimensional data of the work site includes height data of each of the plurality of detection points 28 defined on the surface of the terrain of the work site. The position of each of the plurality of detection points 28 in the global coordinate system is determined on the basis of the current position of the work machine 2 when the three-dimensional data is acquired, the posture of the work machine 2, and the three-dimensional data. Note that the position of the detection point 28 may be defined in the global coordinate system or may be defined in a predetermined coordinate system such as a local coordinate system set in the work machine 2. Time data indicating time is assigned to each of the plurality of detection points 28. The time indicated by the time data refers to the time when the three-dimensional data acquisition unit 62 acquires the detection point 28 or the time when the position data acquisition unit 61 acquires the position data corresponding to the detection point 28. Note that the time of the time data may be regarded as the time when the three-dimensional sensor 13 detects the detection point 28. The time data is stored in association with each of the plurality of detection points 28. Further, attribute data indicating an attribute is assigned to each of the plurality of detection points 28. The attribute indicated by the attribute data refers to an attribute of the detection point 28. The attribute of the detection point 28 includes an attribute related to the terrain of the work site and an attribute related to an obstacle present at the work site. The attribute data is stored in association with each of the plurality of detection points 28.

Method for Setting Stop Position

[0058]FIG. 7 is a plan view schematically illustrating an alarm range 31 and a stop range 32 set in the work machine 2 according to the embodiment. FIG. 8 is a side view schematically illustrating the alarm range 31 and the stop range 32 set in the work machine 2 according to the embodiment. Each of FIGS. 7 and 8 illustrates an alarm range 31A and a stop range 32A when there is an ascending cliff in front of the work machine 2 moving forward. When the ascending cliff is disposed in the alarm range 31A of the work machine 2 moving forward toward the ascending cliff, the alarm control unit 66 activates the alarm device 30. The stop range 32A includes a forward stop position indicating a target stop position of the work machine 2 moving forward. The stop range 32A including the forward stop position is set in front of the excavation blade 18 of the excavation working equipment 9. The forward stop position may be defined at the front end portion of the stop range 32A, at the rear end portion of the stop range 32A, or between the front end portion and the rear end portion of the stop range 32A. When the ascending cliff is disposed in the stop range 32A of the work machine 2 moving forward toward the ascending cliff, the traveling control unit 67 controls the traveling device 8. The traveling control unit 67 stops the travel of the work machine 2 so that the work machine 2 does not come into contact with the ascending cliff.

[0059]The determination unit 64 determines whether or not there is an ascending cliff in front of the work machine 2 on the basis of the detection data of the three-dimensional sensor 13. As illustrated in FIGS. 7 and 8, in a case where the determination unit 64 determines that the type of cliff present ahead in the traveling direction of the work machine 2 is an ascending cliff, the position setting unit 65 sets the stop range 32A in front of the work machine 2. In a case where it is determined that there is an ascending cliff in front of the work machine 2, the traveling control unit 67 controls the traveling device 8 on the basis of the relative position between the forward stop position set in front of the excavation blade 18 and the ascending cliff. In a case where it is determined that there is an ascending cliff in front of the work machine 2, the traveling control unit 67 stops the travel (forward movement) of the traveling device 8 on the basis of the relative position between the forward stop position set in front of the excavation blade 18 and the ascending cliff.

[0060]The traveling control unit 67 stops the travel (forward movement) of the traveling device 8 before the forward stop position enters the ascending cliff or so that the forward stop position coincides with the start position 33 of the ascending cliff.

[0061]FIG. 9 is a plan view schematically illustrating an alarm range 31 and a stop range 32 set in the work machine 2 according to the embodiment. FIG. 10 is a side view schematically illustrating the alarm range 31 and the stop range 32 set in the work machine 2 according to the embodiment. Each of FIGS. 9 and 10 illustrates an alarm range 31B and a stop range 32B when there is a descending cliff in front of the work machine 2 moving forward. When the descending cliff is disposed in the alarm range 31B of the work machine 2 moving forward toward the descending cliff, the alarm control unit 66 activates the alarm device 30. The stop range 32B includes a forward stop position indicating a target stop position of the work machine 2 moving forward. The stop range 32B including the forward stop position is set behind the excavation blade 18 of the excavation working equipment 9. The stop range 32B including the forward stop position is set in front of the rear end portion of the vehicle body 7. The forward stop position may be defined at the front end portion of the stop range 32B, at the rear end portion of the stop range 32B, or between the front end portion and the rear end portion of the stop range 32B. When the descending cliff is disposed in the stop range 32B of the work machine 2 moving forward toward the descending cliff, the traveling control unit 67 stops the travel of the work machine 2 so that the work machine 2 does not fall on the descending cliff.

[0062]The determination unit 64 determines whether or not there is a descending cliff in front of the work machine 2 on the basis of the detection data of the three-dimensional sensor 13. As illustrated in FIGS. 9 and 10, in a case where the determination unit 64 determines that the type of cliff present ahead in the traveling direction of the work machine 2 is a descending cliff, the position setting unit 65 sets the stop range 32B behind the front end portion of the work machine 2. Further, the position setting unit 65 sets the stop range 32B in front of the rear end portion of the work machine 2. The front end portion of the work machine 2 includes the front end portion of the excavation working equipment 9. The rear end portion of the work machine 2 includes the rear end portion of the ripper working equipment 10. As described above, in the embodiment, the stop range 32B is set behind the excavation blade 18 and in front of the rear end portion of the vehicle body 7. In a case where it is determined that there is a descending cliff in front of the work machine 2, the traveling control unit 67 controls the traveling device 8 on the basis of the relative position between the forward stop position set behind the excavation blade 18 and the descending cliff. In a case where it is determined that there is a descending cliff in front of the work machine 2, the traveling control unit 67 stops the travel (forward movement) of the traveling device 8 on the basis of the relative position between the forward stop position set behind the excavation blade 18 and the descending cliff. The traveling control unit 67 stops the travel (forward movement) of the traveling device 8 before the forward stop position enters the descending cliff or such that the forward stop position coincides with the start position 34 of the descending cliff.

[0063]FIG. 11 is a plan view schematically illustrating an alarm range 31 and a stop range 32 set in the work machine 2 according to the embodiment. FIG. 12 is a side view schematically illustrating the alarm range 31 and the stop range 32 set in the work machine 2 according to the embodiment. Each of FIGS. 11 and 12 illustrates an alarm range 31C and a stop range 32C when there is an ascending cliff behind the work machine 2 moving in reverse. When the ascending cliff is disposed in the alarm range 31C of the work machine 2 moving in reverse toward the ascending cliff, the alarm control unit 66 activates the alarm device 30. The stop range 32C includes a reverse stop position indicating a target stop position of the work machine 2 moving in reverse. The stop range 32C including the reverse stop position is set behind the shank 22 of the ripper working equipment 10. The reverse stop position may be defined at the front end portion of the stop range 32C, at the rear end portion of the stop range 32C, or between the front end portion and the rear end portion of the stop range 32C. When the ascending cliff is disposed in the stop range 32C of the work machine 2 moving in reverse toward the ascending cliff, the traveling control unit 67 controls the traveling device 8. The traveling control unit 67 stops the travel of the work machine 2 so that the work machine 2 does not come into contact with the ascending cliff.

[0064]The determination unit 64 determines whether or not there is an ascending cliff behind the work machine 2 on the basis of the detection data of the three-dimensional sensor 13. As illustrated in FIGS. 11 and 12, in a case where the determination unit 64 determines that the type of cliff present behind in the traveling direction of the work machine 2 is an ascending cliff, the position setting unit 65 sets the stop range 32C behind the work machine 2. In a case where it is determined that there is an ascending cliff behind the work machine 2, the traveling control unit 67 controls the traveling device 8 on the basis of the relative position between the reverse stop position set behind the shank 22 and the ascending cliff. In a case where it is determined that there is an ascending cliff behind the work machine 2, the traveling control unit 67 stops the travel (reverse movement) of the traveling device 8 on the basis of the relative position between the reverse stop position set behind the shank 22 and the ascending cliff. The traveling control unit 67 stops the travel (reverse movement) of the traveling device 8 before the reverse stop position enters the ascending cliff or so that the reverse stop position coincides with the start position 33 of the ascending cliff.

[0065]FIG. 13 is a plan view schematically illustrating an alarm range 31 and a stop range 32 set in the work machine 2 according to the embodiment. FIG. 14 is a side view schematically illustrating the alarm range 31 and the stop range 32 set in the work machine 2 according to the embodiment. FIGS. 13 and 14 illustrate an alarm range 31D and a stop range 32D when there is a descending cliff behind the work machine 2 moving in reverse. When the descending cliff is disposed in the alarm range 31D of the work machine 2 moving in reverse toward the descending cliff, the alarm control unit 66 activates the alarm device 30. The stop range 32D includes a reverse stop position indicating a target stop position of the work machine 2 moving in reverse. The stop range 32D including the reverse stop position is set in front of the shank 22 of the ripper working equipment 10. The stop range 32D including the reverse stop position is set behind the front end portion of the vehicle body 7. The reverse stop position may be defined at the front end portion of the stop range 32D, at the rear end portion of the stop range 32D, or between the front end portion and the rear end portion of the stop range 32D. When the descending cliff is disposed in the stop range 32D of the work machine 2 moving in reverse toward the descending cliff, the traveling control unit 67 controls the traveling device 8. The traveling control unit 67 stops the travel of the work machine 2 so that the work machine 2 does not fall on a descending cliff.

[0066]The determination unit 64 determines whether or not there is a descending cliff behind the work machine 2 on the basis of the detection data of the three-dimensional sensor 13. As illustrated in FIGS. 13 and 14, in a case where the determination unit 64 determines that the type of cliff present behind in the traveling direction of the work machine 2 is a descending cliff, the position setting unit 65 sets the stop range 32D in front of the rear end portion of the work machine 2. Further, the position setting unit 65 sets the stop range 32D behind the front end portion of the work machine 2. The rear end portion of the work machine 2 includes the rear end portion of the ripper working equipment 10. The front end portion of the work machine 2 includes the front end portion of the excavation working equipment 9. As described above, in the embodiment, the stop range 32D is set in front of the shank 22 and behind the front end portion of the vehicle body 7. In a case where it is determined that there is a descending cliff behind the work machine 2, the traveling control unit 67 controls the traveling device 8 on the basis of the relative position between the reverse stop position set behind the shank 22 and the descending cliff. In a case where it is determined that there is a descending cliff behind the work machine 2, the traveling control unit 67 stops the travel (reverse movement) of the traveling device 8 on the basis of the relative position between the reverse stop position set behind the shank 22 and the descending cliff. The traveling control unit 67 stops the travel (reverse movement) of the traveling device 8 before the reverse stop position enters the descending cliff or so that the reverse stop position coincides with the start position 34 of the descending cliff.

[0067]FIG. 15 is a plan view schematically illustrating an alarm range 31 and a stop range 32 set in the work machine 2 according to the embodiment. FIG. 16 is a side view schematically illustrating the alarm range 31 and the stop range 32 set in the work machine 2 according to the embodiment. FIGS. 15 and 16 illustrate an alarm range 31E and a stop range 32E when there is an object (obstacle) behind the work machine 2 moving in reverse. In the example illustrated in FIG. 16, the object is another work machine 2B. When the other work machine 2B is disposed in the alarm range 31E of the work machine 2 moving in reverse toward the other work machine 2B, the alarm control unit 66 activates the alarm device 30. The stop range 32E includes a reverse stop position indicating a target stop position of the work machine 2 moving in reverse. The stop range 32E including the reverse stop position is set behind the shank 22 of the ripper working equipment 10. The reverse stop position may be defined at the front end portion of the stop range 32E, at the rear end portion of the stop range 32E, or between the front end portion and the rear end portion of the stop range 32E. When the other work machine 2B is disposed in the stop range 32E of the work machine 2 moving in reverse toward the other work machine 2B, the traveling control unit 67 controls the traveling device 8. The traveling control unit 67 stops the travel of the work machine 2 so that the work machine 2 does not come into contact with another work machine 2B.

[0068]The obstacle sensor 14 detects an object (obstacle) present around the work machine 2. The determination unit 64 determines whether or not there is an object (obstacle) around the work machine 2 on the basis of the detection data of the obstacle sensor 14. The determination unit 64 may determine whether or not there is an object (obstacle) around the work machine 2 on the basis of the detection data of the obstacle sensor 14 and the three-dimensional data indicating the three-dimensional shape of the detection target of the three-dimensional sensor 13. The determination unit 64 may determine that there is an object (obstacle) at a position obtained by integrating the representative point of the standing object detected from the point cloud data included in the three-dimensional data and the detection data of the obstacle sensor 14. In the example illustrated in FIGS. 15 and 16, the determination unit 64 determines whether or not there is another work machine 2B behind the work machine 2 on the basis of the detection data of the obstacle sensor 14. As illustrated in FIGS. 15 and 16, in a case where the determination unit 64 determines that there is another work machine 2B behind the work machine 2 in the traveling direction, the position setting unit 65 sets the stop range 32E behind the work machine 2. In a case where it is determined that there is another work machine 2B behind the work machine 2, the traveling control unit 67 controls the traveling device 8 on the basis of the reverse stop position set behind the shank 22 and the relative position with respect to the other work machine 2B. In a case where it is determined that there is another work machine 2B behind the work machine 2, the traveling control unit 67 stops the travel (reverse movement) of the traveling device 8 on the basis of the reverse stop position set behind the shank 22 and the relative position with respect to the other work machine 2B. The traveling control unit 67 stops the travel (reverse movement) of the traveling device 8 before the reverse stop position enters another work machine 2B.

Control Method

[0069]FIG. 17 is a flowchart illustrating a control method for the work machine 2 according to the embodiment. The determination unit 64 determines whether or not the work machine 2 is moving forward (step S1). In a case where it is determined in step S1 that the work machine 2 is moving forward (step S1: Yes), the determination unit 64 determines whether or not there is an ascending cliff in front of the work machine 2 on the basis of the detection data of the three-dimensional sensor 13F (step S2). In step S2, in a case where it is determined that there is an ascending cliff (step S2: Yes), the traveling control unit 67 stops the forward movement of the work machine 2 on the basis of the first forward stop position included in the stop range 32A described with reference to FIGS. 7 and 8. In a case where it is determined in step S2 that there is a descending cliff (step S2: No), the traveling control unit 67 stops the forward movement of the work machine 2 on the basis of the second forward stop position included in the stop range 32B described with reference to FIGS. 9 and 10.

[0070]In a case where it is determined in step S1 that the work machine 2 is moving in reverse (step S1: No), the determination unit 64 determines whether or not there is an ascending cliff behind the work machine 2 on the basis of the detection data of the three-dimensional sensor 13B (step S5). In a case where it is determined in step S5 that there is an ascending cliff (step S5: Yes), the traveling control unit 67 stops the reverse movement of the work machine 2 on the basis of the first reverse stop position included in the stop range 32C described with reference to FIGS. 11 and 12. In a case where it is determined in step S5 that there is a descending cliff (step S5: No), the traveling control unit 67 stops the reverse movement of the work machine 2 on the basis of the second reverse stop position included in the stop range 32D described with reference to FIGS. 13 and 14.

Computer System

[0071]FIG. 18 is a block diagram illustrating a computer system 1000 according to the embodiment. Each of the management device 3 and the control device 6 described above includes the computer system 1000. The computer system 1000 includes a processor 1001 such as a central processing unit (CPU), a main memory 1002 including a non-volatile memory such as a read only memory (ROM) and a volatile memory such as a random access memory (RAM), a storage 1003, and an interface 1004 including an input/output circuit. The functions of the management device 3 and the control device 6 described above are stored in the storage 1003 as computer programs. The processor 1001 reads the computer program from the storage 1003, develops the computer program in the main memory 1002, and executes the above-described processing according to the program. Note that the computer program may be distributed to the computer system 1000 via a network.

[0072]According to the above-described embodiment, the computer system 1000 or the computer program can execute: acquiring detection data of the three-dimensional sensor 13 that detects the surroundings of the work machine 2; determining whether or not there is a descending cliff in front of the work machine 2 on the basis of the detection data of the three-dimensional sensor 13; and stopping the travel of the traveling device 8 on the basis of a relative position between a forward stop position set behind the excavation blade 18 and the descending cliff in a case where it is determined that there is the descending cliff.

Effects

[0073]As described above, the control system 100 for the work machine 2 according to the embodiment includes: the three-dimensional data acquisition unit 62 that acquires detection data of the three-dimensional sensor 13 that detects the surroundings of the work machine 2; the determination unit 64 that determines whether or not there is a descending cliff in front of the work machine 2 on the basis of the detection data of the three-dimensional sensor 13; and the traveling control unit 67 that stops the travel of the traveling device 8 on the basis of the relative position between the forward stop position set behind the excavation blade 18 and the descending cliff in a case where it is determined that there is the descending cliff. As a result, the travel of the work machine 2 is appropriately stopped at the work site where there is a descending cliff. If the work machine 2 stops at a position away from the start position 34 of the descending cliff, the travel distance of the work machine 2 becomes short, and thus the workability of the work machine 2 may be deteriorated. If the work machine 2 stops at a position greatly exceeding the start position 34 of the descending cliff, the work machine 2 may fall on the descending cliff. By appropriately setting the forward stop position according to the descending cliff, the work machine 2 can be stopped at an appropriate position while suppressing a decrease in workability of the work machine 2.

Other Embodiments

[0074]In the above-described embodiment, the current terrain data creation unit 68 may create the current terrain data of the work site on the basis of at least the three-dimensional data acquired by the three-dimensional data acquisition unit 62. In addition, the current terrain data creation unit 68 may create the current terrain data of the work site on the basis of at least the position data indicating the current position of the work machine 2 acquired by the position data acquisition unit 61.

[0075]In the above-described embodiment, the determination unit 64 may determine the type of cliff present in the traveling direction of the work machine 2 on the basis of the current terrain data of the work site created by the current terrain data creation unit 68. The determination unit 64 may determine whether or not there is an ascending cliff in the traveling direction of the work machine 2 on the basis of the current terrain data of the work site created by the current terrain data creation unit 68. The determination unit 64 may determine whether or not there is a descending cliff in the traveling direction of the work machine 2 on the basis of the current terrain data of the work site created by the current terrain data creation unit 68.

[0076]In the above-described embodiment, at least a part of the functions of the control device 6 may be provided in the management device 3. At least a part of the functions of the management device 3 may be provided in the control device 6.

[0077]In the above-described embodiment, for example, each of the position data acquisition unit 61, the three-dimensional data acquisition unit 62, the obstacle data acquisition unit 63, the determination unit 64, the position setting unit 65, the alarm control unit 66, the traveling control unit 67, the current terrain data creation unit 68, and the current terrain data storage unit 69 may be configured by different hardware.

[0078]In the above-described embodiment, the work machine 2 is a bulldozer. The work machine 2 may be another work machine such as an excavator, a wheel loader, or a motor grader.

REFERENCE SIGNS LIST