Obstacle detection system and obstacle detection method

Abstract

Provided are an obstacle detection system and an obstacle detection method that are capable of improving safety and workability by setting a determination region suitable for a state of a work machine. This obstacle detection system is an obstacle detection system for a work machine, the system comprising: a position sensor that detects the position of the work machine; an object sensor that detects an object in a detection region; and a processor, wherein the processor determines the presence or absence of an obstacle in a set determination region on the basis of the output of the object sensor, determines whether or not the work machine is located in a prescribed region, and changes the size and / or shape of the determination region when it is determined that the work machine is located in the prescribed region.

Description

Obstacle detection system and obstacle detection method

[0001] The present disclosure relates to an obstacle detection system and an obstacle detection method.

[0002] In recent years, working machines utilizing information and communication technology (ICT) have been put into practical use to realize automation at construction sites. Generally, such ICT working machines are equipped with an obstacle detection system capable of detecting obstacles that hinder work, in order to proceed with work while confirming surrounding safety (see, for example, Patent Documents 1 and 2). In the operating environment of working machines, for example, other working machines, infrastructure such as electric power facilities, and steep terrain such as cliffs are the main detection targets. When an obstacle is detected by the obstacle detection system, safety measures such as issuing an alarm, braking the working machine, and notifying an operator who remotely controls the working machine are taken to avoid collision or falling.

[0003] The obstacle detection system described above detects the presence or absence of an obstacle in a predetermined determination area. When determination areas are set in front of and behind the working machine, the obstacle detection system can detect obstacles that may cause collision or falling during forward or reverse travel, and can avoid danger through alarms and braking accompanying obstacle detection.

[0004] Japanese Unexamined Patent Application Publication No. 2019-214868 Japanese Unexamined Patent Application Publication No. 2021-028266

[0005] If the determination area is set broadly, even obstacles with a low possibility of collision or falling can be detected, so safety is improved. However, even objects that are not detection targets may be detected as obstacles, and there is a risk that workability may decrease due to unnecessary alarms and braking. Objects that are not detection targets are objects that are expected to come into contact with the working machine during work, such as windrows, embankments, and undulating terrain that are targets of excavation or earth pushing work.

[0006] An object of the present disclosure is to provide an obstacle detection system and an obstacle detection method that can improve safety and workability by setting a determination area suitable for the state of a working machine.

[0007] The obstacle detection system according to this disclosure is an obstacle detection system for a work machine, comprising: a position sensor for detecting the position of the work machine; an object sensor for detecting an object in a detection area; and a processor, wherein the processor determines, based on the output of the object sensor, whether or not there is an obstacle in a set determination area; whether or not the work machine is in a predetermined area; and, if it is determined that the work machine is in the predetermined area, changes the size and / or shape of the determination area.

[0008] The obstacle detection method relating to this disclosure is an obstacle detection system. An obstacle detection method applicable to a work machine, which determines whether there is an obstacle in a set determination area based on object information of an object in a detection area, determines whether the work machine is in a predetermined area, and changes the size and / or shape of the determination area if it is determined that the work machine is in the predetermined area.

[0009] The obstacle detection system according to this disclosure is an obstacle detection system for a work machine, comprising: an internal sensor for detecting the internal state of the work machine; an object sensor for detecting an object in a detection area; and a processor, wherein the processor determines the presence or absence of an obstacle in a set determination area based on the output of the object sensor, and changes the size and / or shape of the determination area according to the internal state detected by the internal sensor.

[0010] The obstacle detection method relating to this disclosure is an obstacle detection method applicable to a work machine, which determines the presence or absence of an obstacle in a set determination area based on object information of an object in a detection area, and changes the size and / or shape of the determination area according to the internal state of the work machine.

[0011] According to this disclosure, safety and workability can be improved by setting a determination area suitable for the state of the work machine, specifically the position and / or internal state of the work machine.

[0012] Figure 1 is a diagram showing an example of an earthwork system used at a work site. Figure 2 is a diagram showing the configuration of a work machine equipped with an obstacle detection system according to one embodiment of the present disclosure. Figure 3 is a diagram showing the configuration of a work machine equipped with an obstacle detection system according to one embodiment of the present disclosure. Figure 4 is a diagram showing the main part of the control system of the work machine. Figure 5 is a diagram showing current terrain data stored in the auxiliary storage unit. Figure 6 is a diagram showing an example of an excavation method using a work machine. Figure 7 is a flowchart showing an example of obstacle detection processing. Figure 8 is a diagram showing an example of a determination area. Figure 9 is a flowchart showing an example of determination area setting processing according to the first embodiment. Figures 10A and 10B are diagrams showing examples of the first and second determination areas. Figures 11A and 11B are diagrams showing the obstacle detection state when the first and second determination areas are set. Figure 12 is a flowchart showing an example of determination area setting processing according to the second embodiment. Figures 13A to 13C are diagrams showing examples of the first, second, and third determination areas. Figures 14A and 14B show the detection status of obstacles (cliffs) when a second and third judgment area are set.

[0013] Embodiments of this disclosure will be described in detail below with reference to the drawings.

[0014] [First Embodiment] Figure 1 shows an example of an earthwork system A used at a work site. The work site is, for example, a mine where excavation work is carried out.

[0015] As shown in Figure 1, the earthwork system A includes multiple work machines 1 and a control device 2. The work machines 1 and the control device 2 are connected via a predetermined communication network 3, and can send and receive information from each other.

[0016] The work machine 1 is a work machine used in mines, such as a bulldozer, wheel loader, excavator, and dump truck. In this embodiment, the work machine 1 is a bulldozer that performs excavation work.

[0017] The control device 2 is, for example, a computer installed in the control equipment at the work site. The control device 2 can, for example, collect information from the work machine 1 to create and update current terrain data, and remotely operate the work machine 1.

[0018] Communication network 3 is, for example, the Internet, a mobile phone network, a satellite network, or a local area network (LAN). Communication network 3 may be a wireless network or a wired network.

[0019] In the earthwork system A, the working machine 1 and the management device 2 work together to grasp the topography of the work site, the progress of the work, and the location information of the working machine 1 in real time.

[0020] Figures 2 and 3 show the configuration of a work machine 1 equipped with an obstacle detection system S according to one embodiment of the present disclosure. Figure 2 is a side view of the work machine 1 as seen from the side, and Figure 3 is a top view of the work machine 1 as seen from above.

[0021] As shown in Figures 2 and 3, the work machine 1 has a vehicle body 10, a traveling device 20, an excavating device 30, and a ripper device 40.

[0022] The vehicle body 10 has a driver's cab 11. The vehicle body 10 is installed on top of the running gear 20. The driver's cab 11 contains a seat for the operator, various instruments, as well as an operation unit 111, a display unit 112, and an audio output unit 113 (see Figure 4). The vehicle body 10 is also equipped with a power source such as an engine and a battery (not shown).

[0023] The running gear 20 is a device for moving the work machine 1. The running gear 20 has, for example, a pair of crawler tracks 21 called tracks. The work machine 1 moves forward or backward as the crawler tracks 21 rotate due to the driving force of the engine. The work machine 1 also turns by independently controlling the rotational speed (including stopping) and direction of rotation of the left and right crawler tracks 21. The crawler tracks 21 have a large contact area and can exhibit high running performance even on soft ground or uneven terrain.

[0024] The excavation device 30 is an attachment for performing excavation work. Excavation work includes excavating, pushing soil, or leveling the work area. The excavation device 30 is detachably mounted on the front of the vehicle body 10. The excavation device 30 has an excavation blade 31, a lift frame 32, a tilt cylinder 33, and a lift cylinder 34.

[0025] The drilling blade 31 has a cutting edge at its lower tip. The lift frame 32 connects the drilling blade 31 to the traveling device 20. The lift frame 32 may also connect the drilling blade 31 to the vehicle body 10. The tilt cylinder 33 and lift cylinder 34 are actuators that operate the drilling blade 31. The tilt cylinder 33 and lift cylinder 34 are hydraulic cylinders that operate using an engine as a power source, for example. The angle and height (lifting position) of the drilling blade 31 are adjusted by the extension and retraction of the tilt cylinder 33 and lift cylinder 34. The drilling blade 31 is an example of a work machine.

[0026] As the work machine 1 moves forward with the cutting edge of the excavation blade 31 pressed against the ground surface to be worked on, the ground surface is excavated. Also, as the work machine 1 moves forward with the excavation blade 31 pressed against the soil to be worked on, the soil is pushed out and transported.

[0027] The ripper device 40 is an attachment for performing ripping operations. Ripping operations include cutting or crushing the workpiece. The ripper device 40 is detachably mounted, for example, to the rear of the vehicle body 10. The ripper device 40 has a shank 41, a ripper arm 42, a tilt cylinder 43, and a lift cylinder 44.

[0028] The shank 41 has a ripper point at its lower tip. The ripper arm 42 connects the shank 41 to the travel device 20. The ripper arm 42 may also connect the shank 41 to the vehicle body 10. The tilt cylinder 43 and lift cylinder 44 are actuators that operate the shank 41. The tilt cylinder 43 and lift cylinder 44 are hydraulic cylinders that operate using, for example, an engine as a power source. The angle and height (lifting position) of the shank 41 are adjusted by the extension and retraction of the tilt cylinder 43 and lift cylinder 44.

[0029] As the work machine 1 moves forward with the ripper point of the shank 41 embedded in the ground that is the work target, the ground is cut or crushed.

[0030] Figure 4 shows the main components of the control system of the work machine 1. As shown in Figure 4, the work machine 1 includes a control unit 100, an operation unit 111, a display unit 112, an audio output unit 113, a communication unit 114, a position sensor 121, a front sensor 122, a rear sensor 123, and an internal sensor 124, etc.

[0031] The control unit 100 includes a CPU (Central Processing Unit) 101 as an arithmetic / control device (hardware processor), a ROM (Read Only Memory) 102 as main memory, a RAM (Random Access Memory) 103, and an auxiliary storage unit 104, etc. The ROM 102 stores the basic program and basic setting data.

[0032] The auxiliary storage unit 104 is, for example, an auxiliary storage device such as an HDD (Hard Disk Drive), SSD (Solid State Drive), or SD (Secure Digital) card. The auxiliary storage unit 104 stores programs, various data, and so on.

[0033] The auxiliary storage unit 104 stores, for example, a travel control program, an excavation control program, a ripping control program, a current terrain data update program, and an obstacle detection program. The auxiliary storage unit 104 also stores current terrain data that shows the terrain of the work site where the work machine 1 is operating. These programs and current terrain data may also be stored in the ROM 102.

[0034] The CPU 101 reads a program corresponding to the processing content from the ROM 102 or auxiliary storage unit 104, loads it into the RAM 103, and executes the loaded program to centrally control the operation of each block of the work machine 1.

[0035] For example, the control unit 100 functions as a current terrain data update unit that updates the current terrain data when the CPU 101 executes a current terrain data update program. Specifically, the control unit 100 updates the current terrain data based on the outputs of the position sensor 121, the forward sensor 122, the rear sensor 123, and the internal sensor 124.

[0036] For example, the control unit 100 functions as an obstacle detection unit that detects obstacles around the work machine 1 by having the CPU 101 execute an obstacle detection program.

[0037] The work machine 1 may be configured to be remotely controlled by an operator via the control device 2. In this case, the control unit 100 transmits the detection results of the position sensor 121, forward sensor 122, rear sensor 123, and internal sensor 124 to the control device 2 via the communication unit 114 as work machine information for the machine itself. This work machine information is displayed on the display of the control device 2. The operator can constantly monitor the work status and travel status of the work machine 1 based on the displayed work machine information and can remotely control the work machine 1 as needed. When the control unit 100 receives remote control data from the control device 2, it executes travel control and other actions for the machine itself based on this remote control data.

[0038] Furthermore, the remote control of the work machine 1 may be a semi-automatic control system combined with manual operation by an operator. Manual operation may be performed by an operator on board the work machine 1 using the control unit 111 in the driver's cab 11, or by an operator near the work machine 1 using a remote control. The work machine 1 may be a manned work machine that is not remotely controlled, or it may be an unmanned work vehicle that operates without the operator's control. In addition, the work machine 1 may be configured to be remotely controlled by an operator using a remote control device installed in a remote control room separate from the control equipment.

[0039] Furthermore, some or all of the processing performed by the control unit 100 may be carried out by electronic circuits such as a DSP (Digital Signal Processor), ASIC (Application Specific Integrated Circuit), or PLD (Programmable Logic Device) provided according to the processing. Also, at least some of the functions of the control unit 100 may be provided by the management device 2.

[0040] The control unit 111 includes operating levers, pedals, and switches for performing travel operations, digging operations, and ripping operations. Travel operations include operations for moving the work machine 1 forward, backward, and turning. Digging operations include, for example, operations for raising, lowering, and adjusting the angle of the digging blade 31 in the digging device 30. Ripping operations include operations for raising, lowering, and adjusting the angle of the shank 41 in the ripper device 40. When an operator performs an operation through the control unit 111, the control unit 100 outputs a control signal corresponding to the operator's operation to the travel device 20, the digging device 30, or the ripper device 40, and controls their respective operations.

[0041] The display unit 112 is composed of a flat panel display such as a liquid crystal display or an organic EL display. The display unit 112 displays information indicating the working status of the work machine 1 according to a control signal from the control unit 100.

[0042] Note that the operation unit 111 and the display unit 112 may be integrally configured by a flat panel display with a touch panel. Further, the display unit 112 may include an LED (light emitting diode), and may be configured to notify the safety state of the work machine 1 by turning on or blinking the LED.

[0043] The audio output unit 113 is configured of, for example, a speaker. The audio output unit 113 outputs audio (e.g., an alarm buzzer) indicating that there is an obstacle around the work machine 1 in accordance with a control signal from the control unit 100.

[0044] The communication unit 114 is a communication interface such as, for example, a NIC (Network Interface Card), a MODEM (MOdulator-DEModulator), or a USB (Universal Serial Bus). The control unit 100 transmits and receives various types of information to and from the management device 2 connected to the communication network 3 via the communication unit 114. The communication unit 114 may include a communication interface for short-range wireless communication such as NFC (Near Field Communication) and Bluetooth (registered trademark).

[0045] The position sensor 121 detects the position of the own machine of the work machine 1. The position sensor 121 is installed, for example, on an upper portion of the vehicle body 10. The position sensor 121 includes, for example, a GNSS receiver, and detects the position of the own machine using the Global Navigation Satellite System (GNSS).

[0046] GNSS includes the Global Positioning System (GPS). By using GNSS, it is possible to detect the position of the own machine in a global coordinate system defined by coordinate data of latitude, longitude, and altitude. The global coordinate system is a coordinate system fixed to the Earth.

[0047] The front sensor 122 is an object sensor that detects an object in front of the working machine 1. The front sensor 122 is installed, for example, at two locations on the left and right of the upper front side of the vehicle body 10 such that the area in front of the working machine 1 (excavation device 30) serves as a detection area DA1.

[0048] The rear sensor 123 is an object sensor that detects an object behind the working machine 1. The rear sensor 123 is installed, for example, at one location in the widthwise center of the upper rear side of the vehicle body 10 such that the area behind the working machine 1 (ripper device 40) serves as a detection area DA2.

[0049] Outputs of the front sensor 122 and the rear sensor 123 include object information of an object that is a detection target. Based on the outputs of the front sensor 122 and the rear sensor 123, the presence or absence of an object that can become an obstacle can be determined. Objects that can become obstacles, that is, detection targets of the front sensor 122 and the rear sensor 123, include other working machines, infrastructure, and topography of a work site such as cliffs.

[0050] The front sensor 122 and the rear sensor 123 are, for example, three-dimensional sensors capable of three-dimensionally detecting the shape, position, distance, and the like of a detection target. An example of the three-dimensional sensor is a LiDAR sensor (LiDAR: Light Detection and Ranging) that can measure the distance to a target object by irradiating a laser beam and receiving the reflected light thereof. Three-dimensional data indicating the three-dimensional shape of a target object includes point cloud data composed of a plurality of detection points. The point cloud data includes the relative distance, relative position, and relative height between the three-dimensional sensor and the detection points.

[0051] Note that, in addition to LiDAR sensors, a RADAR sensor (RADAR: Radio Detection and Ranging), an infrared sensor, a stereo camera, or a depth camera may be applied to the front sensor 122 and the rear sensor 123, or a combination of these may be applied.

[0052] The internal sensor 124 detects the internal state of the work machine 1. The internal sensor 124 includes a blade position sensor, a shank position sensor, a traction force sensor, a travel sensor, and a posture sensor. The internal sensor 124 is installed, for example, on the machine element to be detected. The internal sensor 124 may also include sensors that detect operation information (operation direction and operation amount) input via the operation unit 111.

[0053] The blade position sensor can detect the raising and lowering position of the drilling blade 31. The shank position sensor can detect the raising and lowering position of the shank 41. The traction force sensor can detect the traction force when the work machine 1 is moving. The travel sensor can detect the direction of travel (forward / reverse) and travel speed when the work machine 1 is moving, as well as the direction of turning (right turn / left turn) and turning speed when it is turning.

[0054] The attitude sensor can detect the attitude of the work machine 1. The attitude sensor is, for example, an inertial measurement unit (IMU) capable of measuring the motion state of an object. An IMU typically has an acceleration sensor and an angular velocity sensor. The attitude sensor can detect the attitude of the work machine 1 based on the acceleration and angular velocity (rotational speed) measured by the IMU. The attitude of the work machine 1 includes the angle of the work machine 1 with respect to the horizontal plane in the front-rear direction (pitch angle) and the angle of the work machine 1 with respect to the horizontal plane in the left-right direction (roll angle).

[0055] Figure 5 shows the current terrain data 200 stored in the auxiliary storage unit 104. The current terrain data 200 is created, for example, based on 3D data acquired by the front sensor 122 and rear sensor 123 of the work machine 1. The current terrain data 200 may be created in the work machine 1 or in the management device 2. Alternatively, the current terrain data 200 may be created using (in combination with) 3D data acquired by fixed-point 3D sensors installed at the work site.

[0056] When the current terrain data 200 is created by the management device 2, the management device 2 periodically acquires 3D data, including the 3D shape of the ground surface at the work site, from each of the multiple work machines 1 present at the work site, and integrates the acquired 3D data to create the current terrain data 200. In addition, when the management device 2 acquires new 3D data from the work machines 1, it updates the existing current terrain data 200 as needed. The current terrain data 200 created by the management device 2 is provided to the work machines 1 as appropriate.

[0057] As shown in Figure 5, the current terrain data 200 includes three-dimensional coordinate data 201 that represents the relief, elevation differences, and gradients of the ground surface at the work site as three-dimensional numerical data. The current terrain data 200 also includes attribute data 202 and time data 203 associated with each detection point P.

[0058] The three-dimensional coordinate data 201 is determined, for example, for each of the multiple detection points P defined on the ground surface of the work site, based on the current position of the work machine 1 when the three-dimensional data was acquired, the orientation of the work machine 1, and the three-dimensional data. The three-dimensional coordinate data 201 may be defined in a global coordinate system, or in a predetermined coordinate system such as a local coordinate system set for each work machine 1.

[0059] The time data 203 indicates the time when the 3D coordinate data of the detection point P was generated. The time indicated by the time data 203 may be, for example, the time when the front sensor 122 and rear sensor 123 of the work machine 1 acquired the 3D data corresponding to the detection point P, or the time when the position sensor 121 acquired the position data corresponding to the detection point P.

[0060] Attribute data 202 indicates the attributes of detection point P. The attributes of detection point P include attributes related to the terrain of the work site and attributes related to obstacles present in the work site. As attributes related to the terrain of the work site, attribute data 202 includes, for example, excavation area information indicating whether or not detection point P is an excavation area. If detection point P is an excavation area, data 204 indicating that it is an excavation area is set as the excavation area information for detection point P. If detection point P is not an excavation area, data (not shown) indicating that it is a non-excavation area is set as the excavation area information for detection point P.

[0061] Excavation area information is set, for example, based on the travel trajectory of the work machine 1 performing the excavation work. For example, the work machine 1 acquires its own position information from the position sensor 121 during the excavation work and updates the excavation area information in the attribute data 202 of the current terrain data 200 stored in the auxiliary storage unit 104. The attribute data 202 with the updated excavation area information is transmitted to the management device 2 at a predetermined timing (for example, at the end of the excavation work). The management device 2 updates the attribute data 202 of the current terrain data 200.

[0062] Furthermore, in the management device 2, if a continuous depression is detected over a predetermined area based on the three-dimensional coordinate data 201 of the current terrain data 200, the excavation area information in the attribute data 202 may be updated to indicate the depression as the excavation area. Moreover, the administrator may manually update the excavation area information in the attribute data 202. In addition, the attribute data may include information indicating a specific area other than the excavation work area (for example, the boundary area with a cliff).

[0063] Figure 6 shows an example of an excavation method using the work machine 1. The method shown in Figure 6 is a method in which the excavation area 300 is excavated in lane units, and finally excavated to a predetermined depth in a bathtub shape, and is called the lane bathtub method.

[0064] In the lane bathtub method, the first step in the excavation process for the first layer is to lower the excavation blade 31 and press the cutting edge against the ground surface to put the work machine 1 into an excavation state. In the excavation state, the shank 41 of the ripper device 40 may be driven into the ground surface. In this state, the work machine 1 is moved forward to excavate the ground surface. The excavation blade 31 is raised to put the work machine 1 into a traveling state, and in this state, the work machine 1 is moved backward to the starting point. By repeatedly moving the work machine 1 forward and backward, the first window 301 of the first lane is formed at a predetermined depth (see Figure 6A).

[0065] Next, the work machine 1 is moved to an area adjacent to the first window 301, and a second window 302 is formed in a second lane parallel to the first window 301. The second window 302 is also formed by the same excavation process as the first window 301. A strip-shaped windrow 303 is formed between the first window 301 and the second window 302 (see Figure 6B).

[0066] Next, the work machine 1 is moved to the first window 301, rotated to face the second window 302, and then moved forward to push the windrow 303 into the second window 302. By repeating the earth-pushing operation, all of the windrow 303 is pushed out into the second window 302 and removed. The pushed-out windrow 303 is scattered throughout the second window 302 (see Figure 6C).

[0067] Next, the work machine 1 is moved to the second window 302, and the windrows 303 scattered in the second window 302 are removed outside the excavation area 300 (see Figure 6D).

[0068] With the above steps, the first excavation process is completed. By similarly carrying out the excavation process for the second, third, and subsequent layers, the excavation area 300 is ultimately excavated into a bathtub shape to a predetermined depth.

[0069] The work machine 1 is equipped with an obstacle detection system S capable of detecting obstacles that may hinder work, in order to proceed with work while confirming the safety of the surroundings. In this embodiment, the obstacle detection system S is composed of a control unit 100, a position sensor 121, a front sensor 122, a rear sensor 123, and an internal sensor 124.

[0070] Figure 7 is a flowchart showing an example of obstacle detection processing performed by the control unit 100. This processing is achieved, for example, when the engine of the work machine 1 is started, and the CPU 101 executes an obstacle detection program.

[0071] As shown in Figure 7, first, in step S11, the control unit 100 sets the determination area 400 that is subject to obstacle detection (determination area setting process). The determination area 400 includes a front determination area 410 set in front of the work machine 1 and a rear determination area 420 set behind the work machine 1 (see Figure 8). The front determination area 410 is set within the detection area DA1 of the front sensor 122. The rear determination area 420 is set within the detection area DA2 of the rear sensor 123.

[0072] As shown in Figure 8, the forward detection area 410 and the rear detection area 420 are each set to be rectangular in shape. The width of the forward detection area 410 in the left-right direction is set to be the same as, for example, the width of the drilling blade 31. The width of the rear detection area 420 in the left-right direction is set to be the same as, for example, the width of the vehicle body 10.

[0073] The forward detection area 410 includes a braking area 411 and a warning area 412. The width of the braking area 411 and the warning area 412 are the same in the left-right direction. The braking area 411 is set on the side closer to the work machine 1, and the warning area 412 is set on the side further away from the work machine 1 (forward of the braking area 411, or possibly including the braking area 411).

[0074] Similarly, the rearward detection area 420 includes the braking area 421 and the alarm area 422. The width of the braking area 421 and the alarm area 422 is the same in the left-right direction. The braking area 421 is set on the side closer to the work machine 1, and the alarm area 422 is set on the side further away from the work machine 1 (behind the braking area 421, or possibly including the braking area 421).

[0075] In step S12, the control unit 100 acquires the outputs (3D data) of the front sensor 122 and the rear sensor 123.

[0076] In step S13, the control unit 100 determines whether or not there is an object that could be an obstacle in the determination area 400, based on the outputs of the front sensor 122 and the rear sensor 123 and the determination area 400 set in step S11. If there is an obstacle (YES in step S13), the process proceeds to step S14. If there is no obstacle (NO in step S13), the process returns to step S12.

[0077] Furthermore, when the work machine 1 is moving forward, the presence or absence of obstacles in the forward determination area 410 may be determined, and when the work machine 1 is moving backward, the presence or absence of obstacles in the rear determination area 420 may be determined. Alternatively, the presence or absence of obstacles may be determined by combining the outputs of the forward sensor 122 and the rear sensor 123 with the current terrain data 200.

[0078] In step S14, the control unit 100 determines whether or not there is an obstacle in the front or rear warning areas 412, 422. If there is an obstacle in the front or rear warning areas 412, 422 (YES in step S14), the process proceeds to step S15. If there is no obstacle in the front or rear warning areas 412, 422 (NO in step S14), that is, if there is an obstacle in the front or rear braking areas 411, 421, the process proceeds to step S16.

[0079] In step S15, the control unit 100 controls the display unit 112 and / or the audio output unit 113 to issue a display and / or audio alarm. The alarm allows the worker to know that there is an obstacle in front of or behind the work machine 1, and to take appropriate safety measures to avoid the obstacle. The alarm may also indicate the location of the obstacle based on whether the obstacle is in the front alarm area 412 or the rear alarm area 422.

[0080] In step S16, the control unit 100 controls the travel device 20 to brake the work machine 1 and stop it from moving. This ensures that obstacles can be reliably avoided even if the worker does not take safety measures or if the worker is unable to take safety measures in time.

[0081] The above obstacle detection process ensures the safety of the work machine 1 during excavation work and while it is traveling.

[0082] Here, if the determination area 400 that is subject to obstacle detection is fixed, objects that are not subject to detection may be detected as obstacles, which may reduce work efficiency due to unnecessary alarms or braking. For example, in the lane bathtub method, when excavating while moving forward, the windrow 303 or sidewall 304 may unintentionally enter the forward determination area 410 or the rear determination area 420, causing unnecessary alarms or braking. In addition to the windrow 303 and sidewall 304, piled soil and uneven terrain are objects that are expected to come into contact with the work machine 1 during excavation work or be located very close to the work machine 1, and it is preferable that they are not easily detected as obstacles during excavation work.

[0083] In the first embodiment, the size of the determination area 400 is changed based on the state of the work machine 1, particularly whether or not the work machine 1's own position is within the excavation area. This prevents unintended restrictions on the work machine 1's movement (including forward, backward, and turning) during excavation work, thereby preventing a decrease in work efficiency.

[0084] Specifically, in this embodiment, in the determination area setting process in step S11 of Figure 7, an appropriate determination area 400 is set based on the state of the work machine 1. In this case, the determination area setting process in step S11 is executed periodically in the flowchart of Figure 7. For example, if it is determined in step S13 that there are no obstacles, the process may proceed to step S11.

[0085] Figure 9 is a flowchart showing an example of the determination area setting process executed by the control unit 100.

[0086] As shown in Figure 9, first, in step S101, the control unit 100 acquires the position information of the work machine 1. The control unit 100 determines the position of the machine based on the output of the position sensor 121, for example.

[0087] In step S102, the control unit 100 determines whether the work machine 1 is in an excavation state (processing as a current terrain data update unit). The control unit 100 determines whether the work machine 1 is in an excavation state based, for example, on the output of the internal sensor 124. If the work machine 1 is in an excavation state (YES in step S102), the process proceeds to step S103. If the work machine 1 is not in an excavation state (NO in step S102), the process proceeds to step S104.

[0088] For example, if the lifting position of the drilling blade 31 detected by the blade position sensor is below a predetermined position, the working machine 1 can be determined to be in a drilling state. Also, for example, if the traction force detected by the traction force sensor is above a predetermined value, the working machine 1 can be determined to be in a drilling state. Alternatively, the presence or absence of a drilling state may be determined comprehensively based on the outputs of the blade position sensor, the traction force sensor, and other internal sensors 124.

[0089] In step S103, the control unit 100 updates the current terrain data 200 stored in the auxiliary storage unit 104 (processing as a current terrain data update unit). Specifically, for the detection point P corresponding to the drilling blade 31 in the current terrain data 200 (see Figure 5), data 204 indicating that it is a drilling area is set in the attribute data 202 of the detection point P.

[0090] In step S104, the control unit 100 acquires the current terrain data 200. The control unit 100 reads the current terrain data 200 stored in the auxiliary storage unit 104, for example. The control unit 100 may also acquire the current terrain data 200 from the management device 2. The attribute data 202 of the current terrain data 200 contains the latest excavation area information.

[0091] In step S105, the control unit 100 determines whether the current location of the machine is within the excavation area based on the machine's position information and the current terrain data 200. For example, the control unit 100 compares the machine's position information with the current terrain data 200 and determines that the machine's position is within the excavation area if the attribute data 202 of the detection point P corresponding to the machine's position contains information indicating that it is within the excavation area. If the machine's position is within the excavation area (YES in step S105), the process proceeds to step S106. If the machine's position is not within the excavation area (NO in step S105), the process proceeds to step S107.

[0092] In step S106, the control unit 100 sets a first determination area 400A for the excavation area as the determination area 400. The first determination area 400A includes a first forward determination area 410A set in front of the work machine 1 and a first rear determination area 420A set behind the work machine 1 (see Figure 10A).

[0093] Furthermore, in step S107, the control unit 100 sets a second determination area 400B for the normal area as the determination area 400. The second determination area 400B includes a second front determination area 410B set in front of the work machine 1 and a second rear determination area 420B set behind the work machine 1 (see Figure 10B).

[0094] In this way, the control unit 100 changes the size of the determination area 400 according to the position of the aircraft. In the determination process of step S13 in Figure 7, the presence or absence of an obstacle is determined based on the determination areas 400A and 400B set in step S106 or S107.

[0095] As shown in Figures 10A and 10B, the first determination area 400A is set to be smaller than the second determination area 400B. Specifically, the first front determination area 410A is set to be smaller in width in the left-right direction and length in the front-back direction compared to the second front determination area 410B. The first rear determination area 420A has the same width in the left-right direction as the second rear determination area 420B, but its length in the front-back direction is set to be smaller. At a minimum, the width in the left-right direction of the first front determination area 410A must be set to be smaller than that of the second front determination area 410B, and the length in the front-back direction of the first front determination area 410A, the length in the front-back direction of the first rear determination area 420A, and the width in the left-right direction may be the same as that of the second determination area 400B.

[0096] In the work machine 1, which is implementing the lane bathtub method, when excavating while moving forward, vibrations may cause the posture of the work machine 1 to become unstable, causing the work machine 1 to tilt relative to the windows 301 and 302, and potentially causing the windrow 303 and sidewall 304 to be detected as obstacles (see Figure 11B). In this embodiment, when excavating while moving forward, the work machine 1 is located in the excavation area, and a first determination area 400A is set, so even if the posture of the work machine 1 becomes unstable, the windrow 303 and sidewall 304 are less likely to enter the first determination area 400A (see Figure 11A). Therefore, unnecessary alarms and braking can be suppressed in the work machine 1, improving work efficiency.

[0097] Furthermore, during excavation work, the likelihood of other work machines or infrastructure being present around work machine 1 is low, so safety is ensured even if the detection area is set to a small size.

[0098] Thus, the obstacle detection system S according to the first embodiment is equipped with the following features individually or in appropriate combinations.

[0099] In other words, the obstacle detection system S is an obstacle detection system for the work machine 1, and comprises a position sensor 121 for detecting the position of the work machine 1, a forward sensor 122 and a rear sensor 123 (object sensors) for detecting objects in the detection area, and a control unit 100 (processor). Based on the outputs of the forward sensor 122 and the rear sensor 123, the control unit 100 determines whether there are obstacles in the set determination area 400, determines whether the work machine 1 is in the predetermined area, and changes the size of the determination area 400 if it determines that the work machine 1 is in the predetermined area.

[0100] Furthermore, the obstacle detection method according to the embodiment is an obstacle detection method applicable to the work machine 1, which determines whether there are obstacles in a set determination area 400 based on object information of objects in detection areas DA1 and DA2 (steps S12 and S13 in Figure 7), determines whether the work machine 1 is in a predetermined area (step S105 in Figure 9), and if it is determined that the work machine 1 is in a predetermined area, changes the size of the determination area (step S106).

[0101] According to the obstacle detection system S and obstacle detection method, a determination area 400 suitable for the state of the work machine 1, specifically the position of the work machine 1, is set, so unnecessary alarms and braking can be suppressed, thereby improving work efficiency while ensuring safety.

[0102] Specifically, in the obstacle detection system S, the determination area 400 includes a first determination area 400A, which is set when the work machine 1 is in the excavation area, and a second determination area 400B, which is set when the work machine 1 is not in the excavation area. The control unit 100 (processor) sets the size of the first determination area 400A to be smaller than the second determination area 400B. This makes it possible to suppress unnecessary alarms and braking in excavation conditions where false detection of obstacles is likely to occur.

[0103] The obstacle detection system S further includes an auxiliary storage unit 104 (storage unit) that stores current terrain data 200 having excavation area information indicating whether or not it is an excavation area, and the control unit 100 (processor) determines whether or not the work machine 1 is in an excavation area based on the excavation area information of the current terrain data 200. This makes it easy to determine whether or not the work machine 1 is in an excavation area.

[0104] The obstacle detection system S further includes an internal sensor 124 that detects the internal state of the work machine 1, and the control unit 100 updates the excavation area information for each detection point of the current terrain data 200 based on the output of the position sensor 121 and the internal sensor 124.

[0105] Specifically, the work machine 1 is equipped with a drilling blade 31, and the internal sensor 124 is a blade position sensor capable of detecting the raising and lowering position of the drilling blade 31. Alternatively, the internal sensor 124 may be a traction force sensor capable of detecting the traction force when the work machine 1 is moving.

[0106] By updating the excavation area information for each detection point in the current terrain data 200 based on the output of the position sensor 121 and the internal boundary sensor 124, the determination area can be appropriately set even when the work machine 1 is about to perform excavation work.

[0107] In the obstacle detection system S, the first determination area 400A includes a first forward determination area 410A set in front of the work machine and a first rear determination area 420A set behind the work machine 1, and the second determination area 400B includes a second forward determination area 410B set in front of the work machine 1 and a second rear determination area 420B set behind the work machine 1, and the control unit 100 (processor) sets the width of the first forward determination area 410A in the left-right direction to be smaller than that of the second forward determination area 410B. This effectively suppresses false detection of obstacles in front of the work machine 1 and suppresses unnecessary alarms and braking.

[0108] In the obstacle detection system S, the control unit 100 (processor) controls the operation of the work machine based on the determination result. Specifically, when the control unit 100 detects an obstacle within the determination area, it issues an alarm and / or brakes the work machine 1. This prevents the work machine 1 from colliding with the obstacle, improving safety. In this case, the system may also issue an alarm when an obstacle is detected within the second determination area 400B and brake the work machine 1 when an obstacle is detected within the first determination area 400A. At the very least, it can suppress braking of the work machine 1 due to false detection of obstacles, thereby improving work efficiency.

[0109] [Second Embodiment] In the second embodiment, the size of the determination area 400 is changed based on the state of the work machine 1, in particular whether or not the work machine 1 is in an excavation state, thereby preventing unintended restriction of the travel movement (including forward, backward, and turning) of the work machine 1 during excavation work and preventing a decrease in work efficiency.

[0110] Specifically, in this embodiment, in the determination area setting process in step S11 of Figure 7, an appropriate determination area 400 is set based on the state of the work machine 1. In this case, the determination area setting process in step S11 is executed periodically in the flowchart of Figure 7. For example, if it is determined in step S13 that there are no obstacles, the process may proceed to step S11.

[0111] Figure 12 is a flowchart showing an example of the determination area setting process executed by the control unit 100.

[0112] As shown in Figure 12, first, in step S201, the control unit 100 acquires the internal state of the work machine 1. The control unit 100 identifies the internal state of the work machine 1, for example, based on the output of the internal sensor 124. The internal state of the work machine 1 includes the working state and the driving state of the work machine 1.

[0113] In step S202, the control unit 100 determines whether the work machine 1 is in an excavation state based on the internal state acquired in step S201. If the work machine 1 is in an excavation state (YES in step S202), the process proceeds to step S203. If the work machine 1 is not in an excavation state (NO in step S202), the process proceeds to step S204.

[0114] For example, if the lifting position of the drilling blade 31 detected by the blade position sensor is below a predetermined position, the working machine 1 can be determined to be in a drilling state. Also, for example, if the traction force detected by the traction force sensor is above a predetermined value, the working machine 1 can be determined to be in a drilling state. Alternatively, the presence or absence of a drilling state may be determined comprehensively based on the outputs of the blade position sensor, the traction force sensor, and other internal sensors 124.

[0115] In step S203, the control unit 100 sets a first determination area 400A for the excavation state as the determination area 400. The first determination area 400A includes a first forward determination area 410A set in front of the work machine 1 and a first rear determination area 420A set behind the work machine 1 (see Figure 13A).

[0116] Furthermore, in step S204, the control unit 100 sets a second determination area 400B for the normal area as the determination area 400. The second determination area 400B includes a second front determination area 410B set in front of the work machine 1 and a second rear determination area 420B set behind the work machine 1 (see Figure 13B).

[0117] Furthermore, in step S205, the control unit 100 determines whether the work machine 1 is in a rotating state based on the internal state acquired in step S201. If the work machine 1 is not in a rotating state ("NO" in step S205), that is, if it is in a traveling state or stopped state, the second determination area 400B set in step S204 is maintained. If the work machine 1 is in a rotating state ("YES" in step S205), the process proceeds to step S206.

[0118] For example, it is possible to determine whether the work machine 1 is in a rotating state based on the output of the travel sensor. Alternatively, for example, it may be possible to determine whether the work machine 1 is in a rotating state based on operation information input through the operation unit 111 (operation lever).

[0119] In step S206, the control unit 100 expands the width of the second determination area 400B set in step S204 in the left-right direction in the rotation direction (see Figure 13C). The expanded determination area is referred to as the third determination area 400C. Figure 13C shows the case where the work machine 1 rotates to the right, and auxiliary areas 411B and 421B are added to the second determination area 400B to set the third determination area 400C. The third determination area 400C includes a third front determination area 410C set in front of the work machine 1 and a third rear determination area 420C set behind the work machine 1.

[0120] In this way, the control unit 100 changes the size of the determination area 400 according to the working state and driving state of the machine. In the determination process of step S13 in Figure 7, the presence or absence of an obstacle is determined based on the determination areas 400A to 400C set in steps S203, S204, and S206.

[0121] As shown in Figures 13A and 13B, the first determination area 400A is set to be smaller than the second determination area 400B. Specifically, the first front determination area 410A is set to be smaller in width in the left-right direction and length in the front-back direction compared to the second front determination area 410B. The first rear determination area 420A has the same width in the left-right direction as the second rear determination area 420B, but its length in the front-back direction is set to be smaller. At a minimum, the width in the left-right direction of the first front determination area 410A must be set to be smaller than that of the second front determination area 410B, and the length in the front-back direction of the first front determination area 410A, the length in the front-back direction of the first rear determination area 420A, and the width in the left-right direction may be the same as that of the second determination area 400B.

[0122] In the work machine 1 implementing the lane bathtub method, when excavating while moving forward, vibrations may cause the work machine 1 to become unstable, tilting relative to the windows 301 and 302, potentially causing the windrow 303 and sidewall 304 to be detected as obstacles (see Figure 11B). In this embodiment, when excavating while moving forward, the work machine 1 is in an excavating state, and the first determination area 400A is set. Therefore, even if the posture of the work machine 1 becomes unstable, the windrow 303 and sidewall 304 are less likely to enter the first determination area 400A (see Figure 11A). Consequently, unnecessary alarms and braking can be suppressed in the work machine 1, improving work efficiency.

[0123] Furthermore, during excavation work, the likelihood of other work machines 1 or infrastructure being present around work machine 1 is low, so safety is ensured even if the detection area is set small. Also, when reversing, the machine is in a driving state rather than an excavation state, so a second detection area 400B is set. However, since work machine 1 can travel in a stable posture, the likelihood of the windrow 303 or sidewall 304 entering the second detection area 400B and being detected as an obstacle is low.

[0124] Furthermore, as shown in Figure 13C, the width of the third determination area 400C is set to be larger in the left-right direction compared to the second determination area 400B. When the work machine 1 turns near the cliff 305, the posture of the work machine 1 becomes unstable and the risk of falling increases, so it is preferable to be notified of the presence of the cliff 305 as early as possible.

[0125] As shown in Figure 14A, when the second determination area 400B is set, the cliff 305 is detected as an obstacle only after the work machine 1 has started to rotate and has entered the second determination area 400B, and the presence of the cliff 305 is reported. In this embodiment, as shown in Figure 14B, when the work machine 1 is rotating, a third determination area 400C is set, which is an extension of the second determination area 400B in the direction of rotation, so that the presence of the cliff 305 can be detected and reported in the early stages of rotation. Therefore, the safety of the work machine 1 is improved.

[0126] Thus, the obstacle detection system S according to the second embodiment is equipped with the following features individually or in appropriate combinations.

[0127] In other words, the obstacle detection system S is an obstacle detection system for the work machine 1, and comprises an internal sensor 124 that detects the internal state of the work machine 1, a front sensor 122 and a rear sensor 123 (object sensors) that detect objects in the detection area, and a control unit 100 (processor). The control unit 100 determines the presence or absence of obstacles in the set determination area 400 based on the outputs of the front sensor 122 and the rear sensor 123, and changes the size of the determination area 400 according to the internal state detected by the internal sensor 124.

[0128] Furthermore, the obstacle detection method according to the embodiment is an obstacle detection method applicable to the work machine 1, which determines the presence or absence of an obstacle in a set determination area 400 based on object information of objects in detection areas DA1 and DA2 (steps S12 and S13 in Figure 7), and changes the size of the determination area according to the internal state of the work machine 1 (Figure 12).

[0129] According to the obstacle detection system S and obstacle detection method, a determination area 400 suitable for the state of the work machine 1, specifically the internal state of the work machine 1, is set, so unnecessary alarms and braking can be suppressed, thereby improving work efficiency while ensuring safety.

[0130] Specifically, in the obstacle detection system S, the determination area 400 includes a first determination area 400A, which is set when the work machine 1 is in an excavation state, and a second determination area 400B, which is set when the work machine 1 is not in an excavation state. The control unit 100 sets the size of the first determination area 400A to be smaller than the second determination area 400B. This makes it possible to suppress unnecessary alarms and braking in the excavation state, where false detection of obstacles is likely to occur.

[0131] In the obstacle detection system S, the first determination area 400A includes a first forward determination area 410A set in front of the work machine 1 and a first rear determination area 420A set behind the work machine 1, and the second determination area 400B includes a second forward determination area 410B set in front of the work machine 1 and a second rear determination area 420B set behind the work machine 1. The control unit 100 sets the width of the first forward determination area 410A in the left-right direction to be smaller than that of the second forward determination area 410B. This effectively suppresses false detection of obstacles in front of the work machine 1 and prevents unnecessary alarms and braking.

[0132] In the obstacle detection system S, the work machine 1 is equipped with a drilling blade 31, and the internal sensor 124 is capable of detecting the raising and lowering position of the drilling blade 31. The internal sensor 124 may also be capable of detecting the traction force when the work machine 1 is moving. This makes it easy to detect whether or not the work machine 1 is in a drilling state.

[0133] In the obstacle detection system S, the control unit 100 expands the width of the second determination area 400B in the direction of rotation when the work machine 1 is rotating. This improves the safety of the work machine 1 because it can detect and notify the presence of a cliff at the beginning of the rotation when turning near a cliff.

[0134] In the obstacle detection system S, the control unit 100 (processor) controls the operation of the work machine based on the determination result. Specifically, when the control unit 100 detects an obstacle within the determination area, it issues an alarm and / or brakes the work machine 1. This prevents the work machine 1 from colliding with the obstacle, improving safety. In this case, the system may also issue an alarm when an obstacle is detected within the second determination area 400B and brake the work machine 1 when an obstacle is detected within the first determination area 400A. At the very least, it can suppress braking of the work machine 1 due to false detection of obstacles, thereby improving work efficiency.

[0135] This disclosure is not limited to the embodiments described above and may be modified without departing from its essence.

[0136] In the first embodiment, the size of the determination area is changed when the work machine 1 is in the excavation area. However, the size of the determination area may be changed (enlarged / reduced) not only when the work machine 1 is in the excavation area, but also according to the position of the work machine 1, that is, based on whether or not the work machine 1 is in a predetermined area. Furthermore, not only the size of the determination area but also the shape of the determination area may be changed according to the position of the work machine 1. For example, the first determination area 400A may be changed to a triangular or trapezoidal shape in relation to the rectangular second determination area 400B.

[0137] Furthermore, in the first embodiment, the current terrain data 200 is updated during the determination area setting process shown in Figure 9, but the updating process for the current terrain data 200 may be performed separately from the excavation area setting process.

[0138] In the second embodiment, the determination area is changed according to the excavation state and the rotation state in the determination area setting process shown in Figure 12, but the size of the determination area may be changed according to either the excavation state or the rotation state. Also, the size of the determination area may be changed (enlarged / reduced) according to internal states other than the excavation state and the rotation state. Furthermore, not only the size of the determination area but also the shape of the determination area may be changed according to the internal state of the work machine 1. For example, the first determination area 400A may be changed to a triangular or trapezoidal shape in relation to the rectangular second determination area 400B.

[0139] Furthermore, the first and second embodiments may be combined to change the size of the determination area according to the position and / or internal state of the working state.

[0140] In this embodiment, the obstacle detection system S is mounted on a bulldozer, which is an example of a work machine 1. However, the obstacle detection system S may be mounted on other work machines 1, such as a wheel loader or an excavator. Furthermore, the processor of the obstacle detection system S may be configured as the processor of the control device 2.

[0141] The embodiments disclosed herein should be considered in all respects to be illustrative and not restrictive. The scope of this disclosure is indicated by the claims rather than the foregoing description, and all modifications within the meaning and scope equivalent to the claims are intended.

[0142] The disclosures in the specifications, drawings, and abstracts contained in Japanese applications No. 2025-042423, filed on March 17, 2025, and No. 2025-042424, filed on March 17, 2025, are incorporated herein by reference.

[0143] 1 Working machine, 2 Management device, 10 Vehicle body, 20 Traveling device, 30 Excavation device, 40 Ripper device, 100 Control unit, 121 Position sensor, 122 Forward sensor (object sensor), 123 Rear sensor (object sensor), 124 Inner environment sensor, 400 Judgment area, 400A First judgment area, 400B Second judgment area, 400C Third judgment area, S Obstacle detection system, A Earthwork system

Claims

1. An obstacle detection system for a work machine, comprising: a position sensor for detecting the position of the work machine; an object sensor for detecting objects in a detection area; and a processor, wherein the processor determines, based on the output of the object sensor, whether or not there are obstacles in a set determination area; determines whether or not the work machine is in a predetermined area; and, if it is determined that the work machine is in the predetermined area, changes the size and / or shape of the determination area.

2. The obstacle detection system according to claim 1, wherein the predetermined area is an excavation area, and the determination area includes a first determination area set when the work machine is in the excavation area and a second determination area set when the work machine is not in the excavation area, and the processor sets the size of the first determination area to be smaller than the second determination area.

3. The obstacle detection system according to claim 2, further comprising a storage unit for storing current terrain data having excavation area information indicating whether or not it is an excavation area, wherein the processor determines whether or not the work machine is in the excavation area based on the current terrain data.

4. An obstacle detection system according to claim 3, further comprising an internal sensor for detecting the internal state of the work machine, wherein the processor updates the excavation area information for each detection point of the current terrain data based on the output of the position sensor and the internal sensor.

5. The obstacle detection system according to claim 4, wherein the work machine comprises a drilling blade, and the internal sensor is capable of detecting the raising and lowering position of the drilling blade.

6. The obstacle detection system according to claim 4, wherein the internal sensor is capable of detecting the traction force when the work machine is in motion.

7. The obstacle detection system according to claim 2, wherein the first determination area includes a first forward determination area set in front of the work machine and a first rear determination area set behind the work machine, the second determination area includes a second forward determination area set in front of the work machine and a second rear determination area set behind the work machine, and the processor sets the width of the first forward determination area in the left-right direction to be smaller than that of the second forward determination area.

8. The obstacle detection system according to claim 1, wherein the processor controls the operation of the work machine based on the determination result.

9. The obstacle detection system according to claim 8, wherein the processor issues an alarm and / or brakes the work machine when it detects the obstacle within the determination area.

10. An obstacle detection method applicable to a work machine, comprising: determining the presence or absence of an obstacle in a set determination area based on object information of an object in a detection area; determining whether the work machine is in a predetermined area; and changing the size and / or shape of the determination area if it is determined to be in the predetermined area.

11. The obstacle detection method according to claim 10, wherein the predetermined area is an excavation area, the determination area includes a first determination area set when the work machine is in the excavation area, and a second determination area set when the work machine is not in the excavation area, and in the step of changing the determination area, the size of the first determination area is set to be smaller than that of the second determination area.

12. The obstacle detection method according to claim 11, comprising storing current terrain data having excavation area information indicating whether or not it is an excavation area, and in the step of changing the determination area, determining whether or not the work machine is in the excavation area based on the excavation area information.

13. The obstacle detection method according to claim 12, wherein the excavation area information is updated for each detection point of the current terrain data based on the position of the work machine and the internal state of the work machine.

14. The obstacle detection method according to claim 12, wherein the work machine is equipped with a drilling blade, and the internal state of the work machine includes the raising and lowering position of the drilling blade.

15. The obstacle detection method according to claim 12, wherein the internal state of the work machine includes the traction force when the work machine is running.

16. The obstacle detection method according to claim 11, wherein the first determination area includes a first forward determination area set in front of the work machine and a first rear determination area set behind the work machine, the second determination area includes a second forward determination area set in front of the work machine and a second rear determination area set behind the work machine, and in the step of changing the determination area, the width of the first forward determination area in the left-right direction is set to be smaller than that of the second forward determination area.

17. The obstacle detection method according to claim 10, wherein the operation of the work machine is controlled based on the determination result.

18. The obstacle detection method according to claim 17, wherein the step of controlling the operation of the work machine is to issue an alarm and / or brake the work machine when the obstacle is detected within the determination area.

19. An obstacle detection system for a work machine, comprising: an internal sensor for detecting the internal state of the work machine; an object sensor for detecting an object in a detection area; and a processor, wherein the processor determines the presence or absence of an obstacle in a set determination area based on the output of the object sensor, and changes the size and / or shape of the determination area according to the internal state detected by the internal sensor.

20. The obstacle detection system according to claim 19, wherein the determination area includes a first determination area set when the work machine is in an excavation state and a second determination area set when the work machine is not in an excavation state, and the processor sets the size of the first determination area to be smaller than the second determination area.

21. The obstacle detection system according to claim 20, wherein the first determination area includes a first forward determination area set in front of the work machine and a first rear determination area set behind the work machine, the second determination area includes a second forward determination area set in front of the work machine and a second rear determination area set behind the work machine, and the processor sets the width of the first forward determination area in the left-right direction to be smaller than that of the second forward determination area.

22. The obstacle detection system according to claim 19, wherein the work machine comprises a drilling blade, and the internal sensor is capable of detecting the raising and lowering position of the drilling blade.

23. The obstacle detection system according to claim 19, wherein the internal sensor is capable of detecting the traction force when the work machine is in motion.

24. The obstacle detection system according to claim 20, wherein the processor expands the widthwise size of the second determination area in the rotational direction when the work machine is in a rotational state.

25. The obstacle detection system according to claim 19, wherein the processor controls the operation of the work machine based on the determination result.

26. The obstacle detection system according to claim 25, wherein the processor issues an alarm and / or brakes the work machine when it detects an obstacle within the determination area.

27. An obstacle detection method applicable to a work machine, comprising: determining the presence or absence of an obstacle in a set determination area based on object information of an object in a detection area; and changing the size and / or shape of the determination area according to the internal state of the work machine.

28. The obstacle detection method according to claim 27, wherein the determination area includes a first determination area set when the work machine is in an excavation state and a second determination area set when the work machine is not in an excavation state, and in the step of changing the determination area, the size of the first determination area is set to be smaller than that of the second determination area.

29. The obstacle detection method according to claim 28, wherein the first determination area includes a first forward determination area set in front of the work machine and a first rear determination area set behind the work machine, the second determination area includes a second forward determination area set in front of the work machine and a second rear determination area set behind the work machine, and in the step of changing the determination area, the width of the first forward determination area in the left-right direction is set to be smaller than that of the second forward determination area.

30. The obstacle detection method according to claim 27, wherein the work machine is equipped with a drilling blade, and the internal state of the work machine includes the raising and lowering position of the drilling blade.

31. The obstacle detection method according to claim 27, wherein the internal state of the work machine includes the traction force when the work machine is running.

32. The obstacle detection method according to claim 28, wherein, in the step of changing the determination area, when the work machine is in a rotating state, the width of the second determination area in the left-right direction is expanded in the rotating direction.

33. The obstacle detection method according to claim 27, wherein the operation of the work machine is controlled based on the determination result.

34. The obstacle detection method according to claim 33, wherein the step of controlling the operation of the work machine is to issue an alarm and / or brake the work machine when the obstacle is detected within the determination area.

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