System including work machine, controller for work machine, and path generation method for work machine

Abstract

A path of traveling in a case where excavation and loading work is automatically controlled is appropriately set. An object around the work machine main body includes an excavation target that is a heap of material excavated by a work implement and a loading target onto which the material is loaded. A controller that generates a travel path of a travel body recognizes the loading target on the basis of a detection result of a sensor, recognizes a loading position in a case where the material is loaded on the loading target, and calculates a minimum distance by which an excavation position at which a work machine excavates the excavation target is to be separated from the loading position by a dimension of the work machine.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to a system including a work machine, a controller for a work machine, and a path generation method for a work machine.BACKGROUND ART

[0002] A conventional wheel loader is disclosed in, for example, JP 2022-157259 A (Patent Literature 1).CITATION LISTPatent Literature

[0003] Patent Literature 1: JP 2022-157259 ASUMMARY OF INVENTIONTechnical Problem

[0004] A wheel loader repeatedly performs excavation work and loading work. In order to automate the excavation work and the loading work, a path of traveling by automatic control is required to be appropriately set.

[0005] The present disclosure proposes a system including a work machine, a controller for a work machine, and a path generation method for a work machine by which a path of traveling in a case where excavation and loading work is automatically controlled can be appropriately set.Solution to Problem

[0006] A system including a work machine according to an aspect of the present disclosure includes a work machine main body including a travel body, a work implement attached to the work machine main body, and a controller that generates a travel path of the travel body. An object around the work machine main body includes an excavation target that is a heap of material excavated by the work implement and a loading target onto which the material is loaded. The travel path of the travel body includes an excavation position at which the work machine excavates the excavation target and a loading position in a case where the material is loaded onto the loading target. The controller recognizes the loading target on the basis of a detection result of the sensor, recognizes the loading position, and calculates a minimum distance by which the excavation position is to be separated from the loading position by a dimension of the work machine.

[0007] A controller for a work machine according to an aspect of the present disclosure generates a travel path of a travel body of a work machine including the travel body and a work implement. The travel path of the travel body includes an excavation position at which the work machine excavates an excavation target that is a heap of material excavated by the work implement and a loading position in a case where material is loaded onto a loading target onto which the material is loaded. The controller recognizes the loading target on the basis of a detection result of a sensor that detects an object around a work machine main body. The controller recognizes the loading position. The controller calculates a minimum distance by which the excavation position is to be separated from the loading position by a dimension of the work machine.

[0008] A path generation method for a work machine according to an aspect of the present disclosure is a method for generating a travel path of a travel body of a work machine including the travel body and a work implement. The travel path of the travel body includes an excavation position at which the work machine excavates an excavation target that is a heap of material excavated by the work implement and a loading position in a case where material is loaded onto a loading target onto which the material is loaded. The path generation method includes the following steps. The first step is to recognize the loading target on the basis of a detection result of a sensor that detects an object around a work machine main body. The second step is to recognize the loading position. The third step is to calculate a minimum distance by which the excavation position is to be separated from the loading position by a dimension of the work machine.Advantageous Effects of Invention

[0009] According to a system including a work machine, a controller for a work machine, and a path generation method for a work machine of the present disclosure, a path of traveling in a case where excavation and loading work is automatically controlled can be appropriately set.BRIEF DESCRIPTION OF DRAWINGS

[0010] FIG. 1 is a side view of a wheel loader as an example of a work machine.

[0011] FIG. 2 is a plan view of the wheel loader illustrated in FIG. 1.

[0012] FIG. 3 is a view for describing excavation and loading work by the wheel loader.

[0013] FIG. 4 is a block diagram illustrating a schematic configuration of a control system of the wheel loader.

[0014] FIG. 5 is a block diagram illustrating a configuration of an automatic control system of the wheel loader.

[0015] FIG. 6 is a schematic view of a vessel of a dump truck as viewed from the side.

[0016] FIG. 7 is a schematic view illustrating a travel path of the wheel loader that performs excavation and loading work.

[0017] FIG. 8 is a flowchart illustrating a flow of processing of generating a travel path of the wheel loader.

[0018] FIG. 9 is a schematic diagram illustrating an example of a loading position with respect to a vessel.DESCRIPTION OF EMBODIMENTS

[0019] Hereinafter, an embodiment will be described with reference to the drawings. In the following description, the same parts and components are denoted by the same reference signs. This also applies to their names and functions. Therefore, detailed descriptions thereof will not be repeated. It is also originally planned that any configurations are extracted from the embodiment and are freely combined.<Overall Configuration of Wheel Loader 1>

[0020] In the embodiment, a wheel loader 1 will be described as an example of a work machine. FIG. 1 is a side view of the wheel loader 1 as an example of a work machine. FIG. 2 is a plan view of the wheel loader 1 illustrated in FIG. 1.

[0021] As illustrated in FIGS. 1 and 2, the wheel loader 1 mainly includes a vehicle body frame 2, a work implement 3, a travel device 4, and a cab 5. The vehicle body frame 2, the cab 5, and the like form the vehicle body of the wheel loader 1. The work implement 3 and the travel device 4 are attached to the vehicle body of the wheel loader 1. The main body of the wheel loader 1 (work machine main body) includes the vehicle body and the travel device 4.

[0022] The travel device 4 causes the vehicle body of the wheel loader 1 to travel, and includes travel wheels 4a and 4b. The wheel loader 1 is a wheeled vehicle including the travel wheels 4a and 4b as traveling rotation bodies on both sides of the vehicle body in a left-right direction. The wheel loader 1 is self-propelled by rotationally driving the travel wheels 4a and 4b, and can perform desired work using the work implement 3. The travel device 4 corresponds to an example of a “travel body”.

[0023] In the present specification, a direction in which the wheel loader 1 travels straight is referred to as a front-rear direction of the wheel loader 1. In the front-rear direction of the wheel loader 1, a side on which the work implement 3 is disposed with respect to the vehicle body frame 2 is defined as a front direction, and a side opposite to the front direction is defined as a rear direction. The left-right direction of the wheel loader 1 is a direction orthogonal to the front-rear direction in a plan view of the wheel loader 1 on a flat ground. The right side and the left side in the left-right direction when viewed in the front direction are the right direction and the left direction, respectively. The vertical direction of the wheel loader 1 is a direction orthogonal to a plane defined by the front-rear direction and the left-right direction. In the vertical direction, the side with the ground is the lower side, and the side with the sky is the upper side.

[0024] The vehicle body frame 2 includes a front frame 2a and a rear frame 2b. The front frame 2a is disposed in front of the rear frame 2b. The front frame 2a and the rear frame 2b are attached to each other by a center pin 10 so as to be movable in the left-right direction.

[0025] A pair of left and right steering cylinders 11 is attached across the front frame 2a and the rear frame 2b. The steering cylinders 11 are hydraulic cylinders. By the steering cylinders 11 being expanded and contracted by hydraulic oil from a steering pump (not illustrated), the travel direction of the wheel loader 1 is changed to the left and right. The front frame 2a and the rear frame 2b form the vehicle body frame 2 including an articulated structure. The wheel loader 1 is an articulated work machine in which the front frame 2a and the rear frame 2b are coupled to each other so as to be bendable.

[0026] The work implement 3 and a pair of the travel wheels (front wheels) 4a are attached to the front frame 2a. The work implement 3 is attached to the front of the vehicle body of the wheel loader 1. The work implement 3 is supported by the vehicle body of the wheel loader 1. Specifically, the work implement 3 is rotatably supported by the vehicle body frame 2, more specifically, the front frame 2a. The work implement 3 is disposed in front of the vehicle body frame 2.

[0027] The work implement 3 includes a boom 14. A base end portion of the boom 14 is rotatably attached to the front frame 2a by a boom pin 9. The boom 14 includes a left boom member 14L and a right boom member 14R. The left boom member 14L and the right boom member 14R are joined to each other so as to be unable to relatively move by a joining member that extends in the left-right direction to form the boom 14 including an integrated structure. The boom pin 9 includes a pair of a left boom pin 9L and a right boom pin 9R. The boom 14 is rotatable with respect to the front frame 2a about the left boom pin 9L and the right boom pin 9R. The left boom pin 9L and the right boom pin 9R rotatably support the work implement 3 with respect to the vehicle body frame 2.

[0028] The work implement 3 includes a bucket 6. The bucket 6 is disposed at the distal end of the work implement 3. The bucket 6 is a work tool for excavation and loading. A blade edge 6a is a distal end portion of the bucket 6. A back surface 6b is a part of the outer surface of the bucket 6. The back surface 6b includes a flat surface. The back surface 6b extends rearward from the blade edge 6a. The bucket 6 is rotatably attached to the boom 14 by a bucket pin 17 located at a distal end of the boom 14. The bucket 6 includes a left boom attachment portion to which the left boom member 14L is attached and a right boom attachment portion to which the right boom member 14R is attached.

[0029] The work implement 3 further includes a bell crank 18 and a link 15. A substantially central portion of the bell crank 18 is rotatably supported by the boom 14 by a support pin 18a located substantially at the center of the boom 14 in the longitudinal direction. The link 15 is coupled to a coupling pin 18c included at the lower end (distal end portion) of the bell crank 18. The link 15 couples the bell crank 18 and the bucket 6. The bell crank 18 and the link 15 are disposed between the left boom member 14L and the right boom member 14R in the left-right direction.

[0030] The front frame 2a and the boom 14 are coupled by a pair of boom cylinders 16. The boom cylinders 16 are hydraulic cylinders. The boom cylinders 16 drive the boom 14 to rotate up and down about the boom pin 9. The base ends of the boom cylinders 16 are attached to the front frame 2a. The distal ends of the boom cylinders 16 are attached to the boom 14. The boom cylinders 16 are hydraulic actuators that move the boom 14 up and down with respect to the front frame 2a. As the boom 14 ascends and descends, the bucket 6 attached to the distal end of the boom 14 also ascends and descends.

[0031] A bucket cylinder 19 couples the bell crank 18 and the front frame 2a. The base end of the bucket cylinder 19 is attached to the front frame 2a. The distal end of the bucket cylinder 19 is attached to a coupling pin 18b included at the upper end portion (base end portion) of the bell crank 18. The bucket cylinder 19 is a hydraulic actuator that rotates the bucket 6 up and down with respect to the boom 14. The bucket cylinder 19 is a work tool cylinder that drives the bucket 6. The bucket cylinder 19 rotationally drives the bucket 6 around the bucket pin 17. The bucket 6 is formed to be operable with respect to the boom 14. The bucket 6 is formed to be operable with respect to the front frame 2a.

[0032] The boom cylinders 16 and the bucket cylinder 19 form a work implement actuator that drives the work implement 3.

[0033] The cab 5 on which the operator boards and a pair of the travel wheels (rear wheels) 4b are attached to the rear frame 2b. The box-shaped cab 5 is disposed behind the boom 14. The cab 5 is mounted on the rear frame 2b. The cab 5 is placed on the vehicle body frame 2. In the cab 5, a seat on which the operator of the wheel loader 1 sits, an operation device 8 to be described below, and the like are disposed.

[0034] A perception device 111 is included on the cab 5. The perception device 111 is disposed, for example, on a ceiling of the cab 5. The perception device 111 is mounted on, for example, an upper surface of the cab 5. The perception device 111 is disposed, for example, on a front portion of the cab 5. The perception device 111 is attached to the cab 5 facing forward, for example, and can acquire information of the front of the cab 5. Details of the perception device 111 will be described below.

[0035] A length L1 illustrated in FIG. 1 is a length from the blade edge 6a of the bucket 6 to the rear end of the vehicle body (total length of the wheel loader 1) in the front-rear direction. A length L2 is a length from the front end of the front wheel 4a to the rear end of the vehicle body in the front-rear direction (vehicle body length of the wheel loader 1). A length L3 is a length (wheelbase length) from the center of the front wheel 4a to the center of the rear wheel 4b in the front-rear direction. A length LA is a length from the center of the front wheel 4a to the bending center of the front frame 2a and the rear frame 2b in the front-rear direction. A length L5 is a length from the bending center of the front frame 2a and the rear frame 2b to the center of the rear wheel 4b in the front-rear direction.

[0036] A length L9 illustrated in FIG. 2 is a length (bucket width) from the left end to the right end of the bucket 6 in the left-right direction. A width direction center 6c of the bucket 6 is a center point of the bucket 6 in the left-right direction.

[0037] Lengths L1 to L5 and L9 illustrated in FIGS. 1 and 2 are included in a specification value of the wheel loader 1. The specification value of the wheel loader 1 further includes a minimum turning radius of the vehicle body. The wheel loader 1 includes an articulated structure in which the front frame 2a and the rear frame 2b are bendable from each other, so that the minimum turning radius of the vehicle body is smaller as compared to a rigid structure. The specification value of the wheel loader 1 is a value unique to each individual of the wheel loader 1, and is stored in a vehicle body controller 50 to be described below.<Excavation and Loading Work>

[0038] The wheel loader 1 according to the present embodiment executes excavation and loading work of scooping material into the bucket 6 and loading the material in the bucket 6 onto a loading target such as a dump truck. The material is earth, sand, rock, ore, or the like excavated at a work site or carried into the work site by a carrying machine such as a dump truck. FIG. 3 is a view for describing excavation and loading work by the wheel loader 1 according to the embodiment.

[0039] FIG. 3(A) illustrates the wheel loader 1 that performs unloaded advancing. The wheel loader 1 travels forward toward an excavation target 200 that is a heap of material. The boom cylinders 16 and the bucket cylinder 19 are operated so that the work implement 3 is in an excavation posture in which the distal end of the boom 14 is at a low position and the bucket 6 is oriented horizontally.

[0040] FIG. 3(B) and 3(C) illustrate the wheel loader 1 performing excavation work. The wheel loader 1 thrusts the blade edge 6a of the bucket 6 into the excavation target 200, and stops forward travel. The blade edge 6a of the bucket 6 bites into the excavation target 200 by an excavation (thrusting) operation illustrated in FIG. 3(B). In this state, when the boom 14 and the bucket 6 rise and the bucket 6 tilts back, the bucket 6 moves along a bucket trajectory BL as indicated by an arrow in FIG. 3(C). With this operation, an excavation (scooping) operation of scooping the excavation target 200 into the bucket 6 illustrated in FIG. 3(C) is executed.

[0041] Depending on the type of the excavation target 200, the excavation (scooping) operation may be completed only by tilting back the bucket 6 once. Alternatively, in the excavation (scooping) operation, the operation of tilting back, neutralizing, and tilting back the bucket 6 again may be repeated.

[0042] FIG. 3(D) illustrates the wheel loader 1 that performs loaded backing. The wheel loader 1 travels backward with the excavation target 200 loaded in the bucket 6. The wheel loader 1 may raise the bucket 6 while traveling backward.

[0043] FIG. 3(E) illustrates the wheel loader 1 that performs loaded advancing. The wheel loader 1 travels forward toward a loading target 300 while raising the bucket 6 or maintaining a state in which the bucket 6 is raised. The wheel loader 1 approaches the loading target 300 until the bucket 6 reaches a predetermined position located substantially directly above the loading platform of the loading target 300.

[0044] FIG. 3(F) illustrates the wheel loader 1 that performs a soil discharging operation to the loading target 300. When the wheel loader 1 approaches the loading target 300 and reaches a predetermined position, the wheel loader 1 dumps the bucket 6 and loads the material in the bucket 6 onto the loading target 300. Thereafter, the wheel loader 1 lowers the boom 14 to return the work implement 3 to the excavation posture while traveling backward to the position at which the forward travel is started in FIG. 3(E).

[0045] The above is a typical operation included in one cycle of the excavation and loading work. The wheel loader 1 repeatedly performs the plurality of operations described above in sequence, excavates the excavation target 200, and loads the excavated material onto the loading target 300 such as a dump truck.

[0046] When excavating the excavation target 200 illustrated in FIG. 3(B) and 3(C), the wheel loader 1 takes a straight posture in which the front frame 2a and the rear frame 2b are not bent from each other. When loading the material in the bucket 6 illustrated in FIG. 3(F) onto the loading target 300, the wheel loader 1 takes a straight posture in which the front frame 2a and the rear frame 2b are not bent from each other.<System Configuration>

[0047] FIG. 4 is a block diagram illustrating a schematic configuration of a control system that controls the wheel loader 1.

[0048] An engine 21 is a driving source that generates a driving force for driving the work implement 3 and the travel device 4, and is, for example, a diesel engine. As the driving source, instead of the engine 21, a motor driven by a power storage body may be used, or both the engine and the motor may be used. The output of the engine 21 is controlled by adjusting the amount of fuel injected into the cylinder of the engine 21.

[0049] The driving force generated by the engine 21 is transmitted to a transmission 23. The transmission 23 shifts the driving force to an appropriate torque and rotational speed. An axle 25 is connected to an output shaft of the transmission 23. The driving force shifted by the transmission 23 is transmitted to the axle 25. The driving force is transmitted from the axle 25 to the travel wheels 4a and 4b (FIGS. 1 and 2). Thus, the wheel loader 1 travels. In the wheel loader 1 of the embodiment, both the travel wheel 4a and the travel wheel 4b form driving wheels that receive a driving force and cause the wheel loader 1 to travel.

[0050] A part of the driving force of the engine 21 is transmitted to a work implement pump 13. The work implement pump 13 is a hydraulic pump that is driven by the engine 21 and operates the work implement 3 by discharged hydraulic oil. The work implement 3 is driven by hydraulic oil from the work implement pump 13. The hydraulic oil discharged from the work implement pump 13 is supplied to the boom cylinders 16 and the bucket cylinder 19 via a main valve 32. When the boom cylinders 16 expand and contract by receiving the supply of the hydraulic oil, the boom 14 moves up and down. When the bucket cylinder 19 receives the supply of the hydraulic oil and expands and contracts, the bucket 6 rotates up and down.

[0051] The wheel loader 1 includes the vehicle body controller 50. The vehicle body controller 50 includes an engine controller 60, a transmission controller 70, and a work implement controller 80.

[0052] The vehicle body controller 50 is generally implemented by reading various programs by a central processing unit (CPU). The vehicle body controller 50 includes a memory (not illustrated). The memory functions as a work memory and stores various programs for implementing the function of the wheel loader 1.

[0053] The operation device 8 is included in the cab 5. The operation device 8 is operated by the operator. The operation device 8 includes a plurality of types of operation members operated by the operator to operate the wheel loader 1. The operation device 8 includes an accelerator pedal 41 and a work implement operation lever 42. The operation device 8 may include a steering wheel, a shift lever, and the like (not illustrated).

[0054] The accelerator pedal 41 is operated to set a target rotation speed of the engine 21. The engine controller 60 controls the output of the engine 21 on the basis of the operation amount of the accelerator pedal 41. When the operation amount (depression amount) of the accelerator pedal 41 is increased, the output of the engine 21 is increased. When the operation amount of the accelerator pedal 41 is reduced, the output of the engine 21 is reduced. The transmission controller 70 controls the transmission 23 on the basis of the operation amount of the accelerator pedal 41.

[0055] The work implement operation lever 42 is operated to operate the work implement 3. The work implement controller 80 controls electromagnetic proportional control valves 35 and 36 on the basis of the operation amount of the work implement operation lever 42.

[0056] The electromagnetic proportional control valve 35 contracts the bucket cylinder 19 to switch the main valve 32 such that the bucket 6 moves in the dumping direction (direction in which the blade edge of the bucket 6 is lowered). Furthermore, the electromagnetic proportional control valve 35 extends the bucket cylinder 19 to switch the main valve 32 such that the bucket 6 moves in the tilting direction (direction in which the blade edge of the bucket 6 is raised). The electromagnetic proportional control valve 36 contracts the boom cylinders 16 to switch the main valve 32 such that the boom 14 is lowered. Furthermore, the electromagnetic proportional control valve 36 extends the boom cylinders 16 to switch the main valve 32 such that the boom 14 is raised.

[0057] A machine monitor 51 receives input of an instruction signal from the vehicle body controller 50 and displays various types of information. The various types of information displayed on the machine monitor 51 may be, for example, information regarding work executed by the wheel loader 1, vehicle body information such as a remaining amount of fuel, a cooling water temperature, and a hydraulic oil temperature, a peripheral image obtained by imaging the periphery of the wheel loader 1, and the like. The machine monitor 51 may be a touch panel, and in this case, a signal generated by the operator touching a part of the machine monitor 51 is output from the machine monitor 51 to the vehicle body controller 50.<Automatic Control System of Wheel Loader 1>

[0058] In automating work of the wheel loader 1, an operation of a skilled operator is desirably reproduced by automatic control. FIG. 5 is a block diagram illustrating a configuration of an automatic control system of the wheel loader 1.

[0059] An automation controller 100 is formed to be able to transmit and receive signals to and from the vehicle body controller 50 described with reference to FIG. 4.

[0060] The automation controller 100 is also formed to be able to transmit and receive signals to and from an external information acquisition unit 110. The external information acquisition unit 110 includes the perception device 111 and a position information acquisition device 112. The perception device 111 and the position information acquisition device 112 are mounted on the wheel loader 1.

[0061] The perception device 111 acquires information of the surroundings of the wheel loader 1. The perception device 111 is attached to a front portion of the upper surface of the cab 5, for example. The perception device 111 corresponds to an example of an “object sensor” that detects an object around the main body of the wheel loader 1 (work machine main body).

[0062] The perception device 111 detects a direction of an object outside the wheel loader 1 and a distance to the object in a non-contact manner. The perception device 111 is, for example, a light detection and ranging (LiDAR) that emits laser light and acquires information of an object. The perception device 111 may be a visual sensor including a camera. The perception device 111 may be a radio detection and ranging (Radar) that acquires information of an object by emitting radio waves. The perception device 111 may be an infrared sensor.

[0063] The position information acquisition device 112 acquires information of the current position of the wheel loader 1. The position information acquisition device 112 acquires position information of the wheel loader 1 in a global coordinate system with reference to the earth using, for example, a satellite positioning system. The position information acquisition device 112 uses, for example, global navigation satellite systems (GNSS), and includes a GNSS receiver. The satellite positioning system calculates the position of the antenna of the GNSS receiver from a positioning signal received by the GNSS receiver from a satellite to calculate the position of the wheel loader 1.

[0064] External information of the wheel loader 1 by the perception device 111 and the position information of the wheel loader 1 by the position information acquisition device 112 are input to the automation controller 100.

[0065] The vehicle body controller 50 is formed to be able to transmit and receive signals to and from a vehicle information acquisition unit 120, and receives input of information of the wheel loader 1 acquired by the vehicle information acquisition unit 120. The vehicle information acquisition unit 120 includes various sensors mounted on the wheel loader 1. The vehicle information acquisition unit 120 includes an articulation angle sensor 121, a vehicle speed sensor 122, a boom angle sensor 123, a bucket angle sensor 124, and a boom cylinder pressure sensor 125.

[0066] The articulation angle sensor 121 detects an articulation angle that is an angle formed by the front frame 2a and the rear frame 2b, and generates a signal of the detected articulation angle. The articulation angle sensor 121 outputs the signal of the articulation angle to the vehicle body controller 50.

[0067] The vehicle speed sensor 122 detects the moving speed of the wheel loader 1 by the travel device 4, for example, by detecting the rotation speed of the output shaft of the transmission 23, and generates a signal of the detected vehicle speed. The vehicle speed sensor 122 outputs the signal of the vehicle speed to the vehicle body controller 50. The vehicle speed sensor 122 corresponds to an example of a travel sensor that detects a traveling status of the travel device 4 (travel body).

[0068] The boom angle sensor 123 includes, for example, a rotary encoder included in the boom pin 9 that is an attachment portion of the boom 14 to the vehicle body frame 2. The boom angle sensor 123 detects an angle of the boom 14 with respect to the horizontal direction (boom angle), and generates a signal indicating the detected angle of the boom 14. The boom angle sensor 123 outputs the signal of the angle of the boom 14 to the vehicle body controller 50.

[0069] The bucket angle sensor 124 includes, for example, a rotary encoder included in the support pin 18a that is a rotation shaft of the bell crank 18. The bucket angle sensor 124 detects an angle of the bell crank 18 with respect to the boom 14 (bell crank angle), and generates a signal of the detected angle of the bell crank 18. The vehicle information acquisition unit 120 or the vehicle body controller 50 calculates an angle of the bucket 6 (bucket angle) with respect to the boom 14 from the detected angle of the bell crank 18.

[0070] The boom angle sensor 123 and the bucket angle sensor 124 correspond to an example of a work implement posture sensor that detects the posture of the work implement 3. The boom angle sensor 123 may be a stroke sensor disposed on the boom cylinder 16. The bucket angle sensor 124 may be a potentiometer or a proximity switch attached to the bucket pin 17, or may be a stroke sensor disposed on the bucket cylinder 19.

[0071] The boom cylinder pressure sensor 125 detects pressure on the bottom side (boom bottom pressure) of the boom cylinder 16, and generates a signal of the detected boom bottom pressure. The boom bottom pressure increases in a case where a load is loaded on the bucket 6, and decreases in a case where the load is empty. The boom cylinder pressure sensor 125 outputs the signal of the boom bottom pressure to the vehicle body controller 50.

[0072] The vehicle body controller 50 outputs information input from the vehicle information acquisition unit 120 to the automation controller 100. The automation controller 100 receives detection values of the vehicle speed sensor 122, the boom angle sensor 123, and the bucket angle sensor 124 via the vehicle body controller 50.

[0073] An actuator 140 is formed to be able to transmit and receive signals to and from the vehicle body controller 50. The actuator 140 is driven upon receiving an instruction signal from the vehicle body controller 50. The actuator 140 includes a brake electromagnetic proportional control valve (EPC) 141 for operating the brake of the travel device 4, a steering EPC 142 for adjusting the traveling direction of the wheel loader 1, a work implement EPC 143 for operating the work implement 3, and a hydraulic mechanical transmission (HMT) 144.

[0074] The electromagnetic proportional control valves 35 and 36 illustrated in FIG. 4 form the work implement EPC 143. The transmission 23 illustrated in FIG. 4 is implemented as the HMT 144 utilizing electronic control. The transmission 23 may be a hydro-static transmission (HST). A power transmission device that transmits power from the engine 21 to the travel wheels 4a and 4b may include an electric drive device of a diesel electric type or the like, or may include any combination of the HMT, the HST, and the electric drive device.

[0075] The transmission controller 70 includes a brake control unit 71 and an accelerator control unit 72. The brake control unit 71 outputs an instruction signal for controlling the operation of the brake to the brake EPC 141. The accelerator control unit 72 outputs an instruction signal for controlling the vehicle speed to the HMT 144.

[0076] The work implement controller 80 includes a steering control unit 81 and a work implement control unit 82. The steering control unit 81 outputs an instruction signal for controlling the traveling direction of the wheel loader 1 to the steering EPC 142. The work implement control unit 82 outputs an instruction signal for controlling the operation of the work implement 3 to the work implement EPC 143.

[0077] The automation controller 100 includes a position estimation unit 101, a path planning unit 102, and a path follow-up control unit 103.

[0078] The position estimation unit 101 estimates the self-position of the wheel loader 1 on the basis of the position information acquired by the position information acquisition device 112. Furthermore, the position estimation unit 101 recognizes a target position on the basis of the external information acquired by the perception device 111. The target position is, for example, an excavation position in the excavation target 200 at which the wheel loader 1 excavates the excavation target 200 using the bucket 6. Further, for example, the target position is a loading position in the loading target 300 that is a relative position of the work implement 3 (bucket 6) with respect to the loading target 300 when material is loaded onto the loading target 300. The perception device 111 may recognize and input a target position to the automation controller 100, and the position estimation unit 101 may recognize a target position on the basis of the detection result detected by the perception device 111.

[0079] The path planning unit 102 generates an optimum path of the wheel loader 1 in a case where the wheel loader 1 is automatically controlled. The optimum path includes a path of traveling by the travel device 4 and a path of operation of the work implement 3.

[0080] For example, the path planning unit 102 generates a path of traveling of the wheel loader 1 that performs unloaded advancing toward the excavation target 200.

[0081] The path planning unit 102 generates a path of the operation of the work implement 3 in excavation work. The path planning unit 102 generates a path of traveling of the wheel loader 1 that performs loaded backing to be separated from the excavation target 200 and a path of operation of the work implement 3 that is performing loaded backing. The path planning unit 102 generates a path of traveling of the wheel loader 1 that performs loaded advancing toward the loading target 300 and a path of operation of the work implement 3 that is performing loaded advancing. The path planning unit 102 generates a path of operation of the work implement 3 that discharges material scooped into the bucket 6 to the loading target 300. The path planning unit 102 generates a path of traveling of the wheel loader 1 that performs unloaded backing to be separated from the loading target 300 and a path of operation of the work implement 3 that is performing unloaded backing.

[0082] The path planning unit 102 also generates an optimum path that connects the current self-position of the wheel loader 1 and a target position to which the wheel loader 1 is heading while executing the excavation and loading work.

[0083] The path follow-up control unit 103 gives an instruction of operation of the travel device 4 and the work implement 3. The path follow-up control unit 103 controls the accelerator, the brake, and the steering such that the wheel loader 1 travels following the optimum path generated by the path planning unit 102. An instruction signal for causing the wheel loader 1 to travel along the optimum path is output from the path follow-up control unit 103 to the brake control unit 71, the accelerator control unit 72, and the steering control unit 81. The path follow-up control unit 103 controls the boom cylinders 16 and the bucket cylinder 19 such that the work implement 3 operates along the optimum path generated by the path planning unit 102. An instruction signal for moving the work implement 3 along the optimum path is output from the path follow-up control unit 103 to the work implement control unit 82.

[0084] An interface 130 is formed to be able to transmit and receive signals to and from the vehicle body controller 50. The interface 130 includes an automation switching switch 131, an engine emergency stop switch 132, and a mode lamp 133.

[0085] The automation switching switch 131 is operated by the operator. The operator operates the automation switching switch 131 to switch between manually operating the wheel loader 1 and automatically controlling the wheel loader 1. The engine emergency stop switch 132 is operated by the operator. In a case where an event that requires emergency stop of the engine 21 occurs, the operator operates the engine emergency stop switch 132. Operation signals of the automation switching switch 131 and the engine emergency stop switch 132 are input to the vehicle body controller 50.

[0086] The mode lamp 133 displays whether the wheel loader 1 is currently in a mode of being manually operated by the operator or in a mode of being automatically controlled. An instruction signal for controlling lighting of the lamp is output from the vehicle body controller 50 to the mode lamp 133.

[0087] The automation controller 100 is also formed to be able to transmit and receive signals to and from a communication device 150. The automatic control system of the wheel loader 1 is formed to be able to gives an instruction of information held by the automation controller 100 to the loading target 300 such as a dump truck via the communication device 150.<Vessel 301>

[0088] The dump truck as an example of the loading target 300 includes a vessel 301. The vessel 301 is an example of a container in which material loaded on the work implement 3 (bucket 6) is loaded. FIG. 6 is a schematic view of the vessel 301 of the dump truck as viewed from the side. In FIG. 6 and subsequent FIG. 9, a schematic shape of the vessel 301 viewed from the left side of the dump truck is illustrated. A thick line in the drawing indicates a schematic shape when a surface that forms the internal shape of the vessel 301 is viewed from the left side of the dump truck.

[0089] In FIGS. 6 and 9, the left-right direction in the drawings corresponds to the front-rear direction of the dump truck (front-rear direction of the vessel 301). In FIGS. 6 and 9, the left direction in the drawing is the front direction of the dump truck (vessel 301), and the right direction in the drawing is the rear direction of the dump truck (vessel 301). In FIGS. 6 and 9, the direction perpendicular to the drawing corresponds to the left-right direction of the dump truck (left-right direction of the vessel 301). In FIGS. 6 and 9, the vertical direction in the drawing corresponds to the vertical direction of the dump truck (vertical direction of the vessel 301).

[0090] The vessel 301 is included at a rear portion of the dump truck. A cab is included in front of the dump truck, and the vessel 301 is disposed behind the cab.

[0091] The vessel 301 includes a structure in which heavy material including earth and sand, crushed stones, and the like can be loaded.

[0092] As illustrated in FIG. 6, the vessel 301 includes a bottom surface 302, a front wall surface 303, and a rear inclined surface 305. The bottom surface 302 has a flat shape. The bottom surface 302 has a planar shape that extends in the front-rear direction and the left-right direction of the dump truck (vessel 301).

[0093] The front wall surface 303 has a flat shape. The front wall surface 303 extends forward and upward from the front end of the bottom surface 302. The front wall surface 303 extends upward, being inclined toward the front. The front wall surface 303 forms a front wall surface of the vessel 301. The wall surface in front of the vessel 301 is inclined upward toward the front. The front wall surface 303 includes a front upper edge 304. The front upper edge 304 extends in the left-right direction. The front upper edge 304 forms a front edge of the vessel 301.

[0094] The rear inclined surface 305 has a flat shape. The rear inclined surface 305 extends rearward and upward from the rear end of the bottom surface 302. The rear inclined surface 305 extends upward, being inclined toward the rear. The rear inclined surface 305 is inclined upward toward the rear. The rear inclined surface 305 includes a rear upper edge 306. The rear upper edge 306 extends in the left-right direction.

[0095] The rear upper edge 306 forms a rear edge of the vessel 301. The rear upper edge 306 is located lower than the front upper edge 304.

[0096] FIG. 6 illustrates a shape of the vessel 301 without a tailgate. In a case where the vessel 301 includes a tailgate, the tailgate is disposed to extend upward from the rear end of the rear inclined surface 305. The upper edge of the tailgate forms the rear upper edge 306.<Travel Path Generation Processing in Case of Automatic Excavation and Loading Work>

[0097] Processing of generating a path of traveling of the wheel loader 1 in a case where the excavation and loading work described with reference to FIG. 3 is automatically controlled will be described below. FIG. 7 is a schematic view illustrating a travel path of the wheel loader 1 that performs the excavation and loading work. FIG. 8 is a flowchart illustrating a flow of processing of generating a travel path of the wheel loader 1.

[0098] The excavation target 200 illustrated in FIG. 7 is a heap of material excavated by the bucket 6 of the wheel loader 1. The excavation target 200 may be a heap of material accumulated in a material accumulation place such as a stockyard. The excavation target 200 may be a heap of material formed in a vacant lot. The excavation target 200 includes a top portion 201 having the highest heap height and a skirt 202 on a front side (side on which the wheel loader 1 excavates the excavation target 200. A lower side in FIG. 7). The skirt 202 is schematically illustrated linearly. The heap height of the excavation target 200 is not uniform, and the heap height gradually decreases from the top portion 201 toward the skirt 202.

[0099] In the vicinity of the skirt 202, the excavation target 200 includes a low heap area 203 in which the accumulation amount of material is small and the heap height is low, and an accumulation area 204 in which the accumulation amount of material is larger than the low heap area 203 and the heap height is higher than the low heap area 203.

[0100] As illustrated in FIG. 8, first, in step S11, the loading target 300 such as a dump truck stops at any place with respect to the excavation target 200. The loading target 300 basically stops at a stop position following rules of the work site, but may stop at any stop position different from the stop position following the rules of the work site by determination of an operator who operates the loading target 300 or by an instruction of control for monitoring the work site.

[0101] In step S12, the perception device 111 mounted on the wheel loader 1 detects the excavation target 200 and the loading target 300. The object around the wheel loader 1 detected by the perception device 111 includes the excavation target 200 and the loading target 300. The perception device 111 inputs the detection result of the excavation target 200 and the loading target 300 to the position estimation unit 101 of the automation controller 100.

[0102] The position estimation unit 101 recognizes the excavation target 200 and the loading target 300 on the basis of the detection result of the perception device 111.

[0103] The position estimation unit 101 recognizes the position and shape of a heap of material that is the excavation target 200. The position estimation unit 101 recognizes the position and shape of the vessel 301 of the loading target 300. The position estimation unit 101 recognizes an angle θ1 formed by the skirt 202 of the excavation target 200 and the left side surface of the vessel 301.

[0104] In step S13, the path planning unit 102 of the automation controller 100 recognizes a loading position A1 that is a relative position of the work implement 3 (bucket 6) with respect to the loading target 300 when material is loaded onto the loading target 300 in the loading target 300 such as a dump truck.

[0105] FIG. 9 is a schematic diagram illustrating an example of the loading position A1 with respect to the vessel 301. FIG. 9 schematically illustrates the vessel 301 viewed from the left side of the loading target 300. FIG. 9 also schematically illustrates the bucket 6 viewed from the rear of the wheel loader 1 (viewed in the front direction). The bucket 6 includes the blade edge 6a that extends in the width direction. A center point 6aC is a center point of the blade edge 6a in the width direction of the bucket 6.

[0106] The bucket 6 illustrated in FIG. 9 is in a full dump posture. The bucket 6 in the posture illustrated in FIG. 9 moves in the dumping direction to the maximum. When the bucket 6 is in the posture illustrated in FIG. 9, the cylinder stroke length of the bucket cylinder 19 is minimized.

[0107] As illustrated in FIG. 7, the wheel loader 1 travels forward from the side (left side) of the loading target 300 toward the vessel 301 and performs the loading work.

[0108] The width direction of the bucket 6 during the loading work coincides with the front-rear direction (in FIG. 9, left-right direction in the drawing) of the loading target 300 (vessel 301). Since the wheel loader 1 takes a straight posture during the loading work, the left-right direction of the wheel loader 1 coincides with the width direction of the bucket 6.

[0109] FIG. 9 illustrates material M loaded from the bucket 6 onto the vessel 301 of the loading target 300. The path planning unit 102 recognizes the position of the upper end of the left side surface of the vessel 301 corresponding to the center point 6aC of the blade edge 6a of the bucket 6 in the front-rear direction of the loading target 300 in a case where the material M loaded onto the vessel 301 does not spill from the vessel 301 as the loading position A1.

[0110] The loading position A1 is set as a position at which the right end of the bucket 6 is separated from the rear upper edge 306 of the vessel 301 by a predetermined distance when the bucket 6 in the full dump posture is viewed from the rear of the wheel loader 1 (viewed in the forward direction). The relative position of the right end of the bucket 6 with respect to the center point 6aC of the blade edge 6a is calculated from the dimension in the width direction of the bucket 6. In a case where the bucket 6 is at the loading position A1, the right end of the bucket 6 is separated forward from the rear upper edge 306 by a predetermined distance in the front-rear direction of the loading target 300.

[0111] Specifically, the path planning unit 102 determines the loading position A1 at a position at which the material M does not spill from the vessel 301 when the material M is loaded onto the vessel 301 at the angle of repose. For example, the angle of repose 30° of sand can be used for determining the loading position A1 such that the angle formed by the material M with respect to the front-rear direction of the loading target 300 at the rear upper edge 306 (FIG. 6) is 30° or less.

[0112] In step S14, the path planning unit 102 calculates a minimum distance x1 at which the wheel loader 1 can perform V-shape traveling from the specification value of the wheel loader 1. The V-shape traveling is a typical path of traveling in a case where the wheel loader 1 performs the excavation and loading work, and the travel path of the wheel loader 1 has a V-shape. In a case where the wheel loader 1 performs V-shape traveling to perform the excavation and loading work, the travel path is assumed to be efficient since the travel distance of the wheel loader 1 is minimized.

[0113] Referring to FIGS. 3 and 7, after excavating the excavation target 200, the wheel loader 1 is switched from forward movement to backward movement, and performs loaded backing. The wheel loader 1 is switched from backward movement to forward movement, and performs loaded advancing toward the loading position A1 of the loading target 300. A position at which the operation of the wheel loader 1 is switched from the loaded backing to the loaded advancing is referred to as a turning-back position. The wheel loader 1 that performs the loaded backing may travel straight from the excavation target 200 to the turning-back position. At least a part of the path on which the wheel loader 1 that performs the loaded advancing travels toward the loading position A1 of the loading target 300 may have a curved shape, typically an arc shape.

[0114] The specification value of the wheel loader 1 includes the lengths L1 to L5 and L9 of respective parts of the wheel loader 1 described with reference to FIGS. 1 and 2. As described with reference to FIG. 1, the length L1 is the total length of the wheel loader 1, and is the dimension of the wheel loader 1 in the front-rear direction. The specification value of the wheel loader 1 also includes a minimum radius in which the wheel loader 1 can turn without stationary steering in which steering is performed while the wheel loader 1 is stopped.

[0115] When loading the material in the bucket 6 onto the vessel 301 of the loading target 300, the wheel loader 1 takes a straight posture in which the front frame 2a and the rear frame 2b are not bent from each other. In a case where the material in the bucket 6 is loaded onto the vessel 301 of the loading target 300, the wheel loader 1 takes a posture in which the width direction of the bucket 6 coincides with the front-rear direction of the loading target 300 and the width direction center 6c (FIG. 2) of the bucket 6 is adjusted to the loading position A1.

[0116] As illustrated in FIG. 7, the path planning unit 102 can set a position at which the center point 6aC (FIG. 9) of the blade edge 6a of the bucket 6 is separated by the length L1 from the left side surface of the vessel 301 in the left-right direction of the loading target 300 and the center point 6aC of the blade edge 6a is separated by the length L1 from the skirt 202 of the excavation target 200 as a temporary turning-back position T1.

[0117] The dimension of the wheel loader 1 for determining the temporary turning-back position T1 is not limited to the length L1. The work implement 3 can change its posture with respect to the vehicle body of the wheel loader 1, and the length L1 may vary with movement of the work implement 3. The length L1 may vary by replacing the bucket 6. On the other hand, the length L2 that is an example of the main body dimension of the wheel loader 1 is a dimension in the front-rear direction of the wheel loader 1, and is a constant dimension regardless of the work implement 3. The path planning unit 102 may determine the temporary turning-back position T1 on the basis of the length L2.

[0118] The path planning unit 102 sets a curved path P that smoothly connects the width direction center 6c (that is, loading position A1) of the bucket 6 in a case where the wheel loader 1 takes a posture of loading the material in the bucket 6 onto the loading target 300 and the width direction center 6c of the bucket 6 in a case where the wheel loader 1 is at the temporary turning-back position T1.

[0119] The path planning unit 102 confirms that the wheel loader 1 traveling along the path P can travel without stationary steering. If the path planning unit 102 determines that stationary steering is necessary for causing the wheel loader 1 to travel along the path P, the path planning unit can reset a position separated farther from the left side surface of the vessel 301 as a temporary turning-back position.

[0120] For example, the path planning unit 102 may reset, as the temporary turning-back position, a position obtained by translating the temporary turning-back position T1 illustrated in FIG. 7 in an extending direction of the skirt 202 of the excavation target 200, the direction being away from the loading target 300 (right direction in FIG. 7).

[0121] The path planning unit 102 again sets a path that smoothly connects the reset temporary turning-back position and the loading position A1, and can repeatedly confirm whether the wheel loader 1 traveling along the path can travel without stationary steering.

[0122] The path planning unit 102 sets the path P such that the wheel loader 1 traveling along the path P can turn without stationary steering. The wheel loader 1 that travels along the path P turns in a turning radius larger than a minimum radius in which the wheel loader 1 can turn without stationary steering. The path P is a trajectory followed by the width direction center 6c of the bucket 6 in a case where the wheel loader 1 turns in a turning radius in which the wheel loader 1 can turn without stationary steering.

[0123] The path planning unit 102 can set a distance from the loading position A1 to the temporary turning-back position T1 in the extending direction of the skirt 202 of the excavation target 200 (left-right direction in FIG. 7) as a distance x1. A position to which the width direction center 6c (FIG. 2) of the bucket 6 to be directed in the extending direction of the skirt 202 of the excavation target 200 when the wheel loader 1 excavates the excavation target 200 is defined as an excavation position. The distance x1 is set as the minimum distance by which the excavation position at which the wheel loader 1 excavates the excavation target 200 is to be separated from the loading position A1 recognized as the position at which material is loaded onto the loading target 300.

[0124] In step S15, the path planning unit 102 sets the position of the skirt 202 separated from the loading position A1 by the distance x1 in the extending direction of the skirt 202 of the excavation target 200 as a temporary excavation position B1.

[0125] In step S16, the path planning unit 102 selects an excavation position Bx at a position separated farther from the loading target 300 than the temporary excavation position B1 in the extending direction of the skirt 202 of the excavation target 200.

[0126] The path planning unit 102 selects the excavation position Bx at a position separated from the loading position A1 by a distance greatly larger than the distance x1. The temporary excavation position B1 is a position at which the distance to the loading position A1 can be set to the minimum distance x1, and the excavation target 200 may be excavated at a position separated farther from the loading target 300 than the temporary excavation position B1. The distance between the excavation position Bx and the loading position A1 may be larger than the distance x1.

[0127] The path planning unit 102 recognizes the shape of the excavation target 200 on the basis of a detection result of the perception device 111. The path planning unit 102 can select the excavation position Bx on the basis of the shape of the excavation target 200. The path planning unit 102 can select, as the excavation position Bx, a distance that can minimize a travel distance by which the wheel loader 1 that excavates the excavation target 200 advances toward the excavation target 200 so as to scoop material into the bucket 6 and load a certain amount of the material onto the work implement 3, typically, so as to fully load the material into the bucket 6.

[0128] In the example illustrated in FIG. 7, the excavation target 200 includes the low heap area 203 and the accumulation area 204 in the vicinity of the skirt 202. The wheel loader 1 can scoop more material into the bucket 6 with a short travel distance by traveling forward toward the accumulation area 204 and excavating the excavation target 200 rather than traveling forward toward the low heap area 203 and excavating the excavation target 200. The wheel loader 1 travels forward toward the accumulation area 204 and excavates the excavation target 200, so that the bucket 6 can be filled with the material at a position closer to the skirt 202. Therefore, the path planning unit 102 can select a substantially central position of the accumulation area 204 in the extending direction of the skirt 202 as the excavation position Bx.

[0129] In the example illustrated in FIG. 7, the accumulation area 204 is located at a position separated farther from the loading target 300 than the temporary excavation position B1, and a position corresponding to the accumulation area 204 can be selected as the excavation position Bx. In a case where the accumulation area 204 is located closer to the loading target 300 than the temporary excavation position B1, the position corresponding to the accumulation area 204 cannot be selected as the excavation position Bx. In this case, another position separated farther from the loading target 300 than the temporary excavation position B1 is selected as the excavation position Bx.

[0130] In step S17, the path planning unit 102 generates the shortest path that connects the loading position A1 and the excavation position Bx. The path planning unit 102 can determine a position separated from the skirt 202 of the excavation target 200 by the length L1 using the excavation position Bx as a starting point as a turning-back position Tx. The path planning unit 102 can generate a path of a straight line that connects the excavation position Bx and the turning-back position Tx as a path of unloaded advancing of the wheel loader 1 toward the excavation target 200 and as a path of loaded backing of the wheel loader 1 away from the excavation target 200.

[0131] The travel path when the wheel loader 1 performs unloaded advancing and when the wheel loader 1 performs loaded backing is separated from the loading position A1 by a distance greatly larger than the distance x1.

[0132] The path planning unit 102 can generate a path obtained by combining a straight line and a curve having any curvature such that the wheel loader 1 that starts performing loaded advancing from the turning-back position Tx causes the center point 6aC of the blade edge 6a of the bucket 6 to reach the loading position A1 of the loading target 300, and the width direction of the bucket 6 when the center point 6aC reaches the loading position A1 coincides with the front-rear direction of the loading target 300. Since the curvature radius of the curve included in this path is larger than the minimum radius in which the wheel loader 1 can turn without stationary steering, the wheel loader 1 can travel forward from the turning-back position Tx to the loading position A1 without stationary steering. The path planning unit 102 can set the generated path as a path for loaded advancing of the wheel loader 1 toward the loading target 300 and a path for unloaded backing of the wheel loader 1 away from the loading target 300.

[0133] By a position separated from the loading position A1 by a distance greatly larger than the distance x1 being set as the turning-back position Tx, the wheel loader 1 that performs loaded advancing from the turning-back position Tx toward the loading position A1 can make the width direction of the bucket 6 coincide with the front-rear direction of the loading target 300 when the bucket 6 reaches the loading position A1 without stationary steering.

[0134] The path planning unit 102 may generate a path such that the wheel loader 1 at the turning-back position Tx takes a straight posture. The path planning unit 102 may generate a path such that the front frame 2a and the rear frame 2b take a bending posture at the turning-back position Tx.

[0135] In this way, a series of processing for generating a path of traveling of the wheel loader 1 is ended (“end” in FIG. 8).<Actions and Effects>

[0136] Although there is a description partially overlapping with the above description, the characteristic configurations and actions and effects of the present embodiment will be collectively described as follows.

[0137] As illustrated in FIGS. 5, 7, and 8, the position estimation unit 101 of the automation controller 100 recognizes the loading target 300 onto which material loaded on the work implement 3 is loaded on the basis of a detection result of the perception device 111. The path planning unit 102 of the automation controller 100 recognizes the loading position A1 in a case where the material is loaded onto the loading target 300. The path planning unit 102 calculates the minimum distance x1 by which the excavation position at which the wheel loader 1 excavates the excavation target 200 when the wheel loader 1 executes the excavation and loading work is to be separated from the loading position A1 by the dimension of the wheel loader 1.

[0138] The path of traveling in a case where the excavation and loading work is automatically controlled can be appropriately set by the shortest path on which traveling can be performed without stationary steering by the turning ability of the wheel loader 1 being determined from the dimension of the wheel loader 1. The shortest path on which the wheel loader 1 can perform V-shape traveling can be set, and the excavation and loading work can be efficiently executed.

[0139] As illustrated in FIGS. 1 and 7, the dimension of the wheel loader 1 may include the dimension in the front-rear direction of the wheel loader 1. The distance x1 can be calculated from the length L1 or the like that is the total length of the wheel loader 1 in the front-rear direction, and the path of traveling in a case where the excavation and loading work is automatically controlled can be appropriately set.

[0140] As illustrated in FIG. 7, the travel path when after the wheel loader 1 excavates the excavation target 200, the wheel loader 1 performs loaded backing may be separated from the loading position A1 by a distance greatly larger than the distance x1. By the path of traveling of the wheel loader 1 being set at a position separated from the loading position A1 by a distance greatly larger than the distance x1, the wheel loader 1 can be caused to travel without stationary steering.

[0141] As illustrated in FIG. 7, the path planning unit 102 may recognize the shape of the excavation target 200 on the basis of a detection result of the perception device 111 and select the excavation position Bx on the basis of the shape of the excavation target 200. An area where the wheel loader 1 can excavate the excavation target 200 is calculated according to the distance x1, and where to set the excavation position Bx in the excavatable area can be selected from the shape of the excavation target 200.

[0142] Since the path of traveling of the wheel loader 1 can be appropriately set, the excavation and loading work can be efficiently executed.

[0143] As illustrated in FIG. 7, the path planning unit 102 can select, as the excavation position Bx, a position that can minimize a travel distance by which the wheel loader 1 that excavates the excavation target 200 advances toward the excavation target 200 so as to load a certain amount of the material onto the work implement 3.

[0144] By the path of traveling in a case where the wheel loader 1 performs the excavation work being set to the shortest path, the excavation work can be efficiently performed.

[0145] As illustrated in FIG. 7, the path planning unit 102 may determine the turning-back position Tx at which the wheel loader 1 is switched from loaded backing to loaded advancing by the dimension of the wheel loader 1. The path planning unit 102 can determine a position separated from the excavation target 200 by the length L1 using the excavation position Bx as a starting point as the turning-back position Tx, and can appropriately set a path of traveling in a case where the excavation and loading work is automatically controlled.

[0146] As illustrated in FIGS. 1 and 2, the main body of the wheel loader 1 may include the front frame 2a and the rear frame 2b bendable with respect to the front frame 2a. The wheel loader 1 includes an articulated structure in which the front frame 2a and the rear frame 2b are bendable from each other, so that the turning radius in the case of turning traveling can be reduced. The path of traveling can be shortened in a case where the wheel loader 1 performs the excavation and loading work.

[0147] As illustrated in FIG. 7, the wheel loader 1 may take a straight posture in which the front frame 2a and the rear frame 2b are not bent from each other in a case where the excavation target 200 is excavated and in a case where the material loaded on the work implement 3 is loaded onto the loading target 300. By the wheel loader 1 taking a straight posture in a case where the excavation target 200 is excavated, the traction force of the vehicle can be sufficiently transmitted to the bucket 6 at the distal end of the work implement 3. By the wheel loader 1 taking a straight posture in a case where the material is loaded onto the loading target 300, the vehicle can be stabilized.

[0148] As illustrated in FIGS. 7 and 8, the path planning unit 102 may generate a travel path of the travel device 4 that can travel without stationary steering. Since a travel path on which the wheel loader 1 turns without stationary steering in which steering is performed while the wheel loader 1 is stopped is generated, local wear of the front wheel 4a can be reduced, and durability of the front wheel 4a can be improved.

[0149] In the above embodiment, the position estimation unit 101 of the automation controller 100 recognizes the position of the loading target 300 on the basis of a detection result of the perception device 111. The present disclosure is not limited thereto, and information of the self-position of the loading target 300 may be input from the loading target 300 to the automation controller 100 by inter-vehicle communication between the automation controller 100 and the loading target 300 via the communication device 150. The position estimation unit 101 can recognize the relative position of the loading target 300 with respect to the wheel loader 1 from information of the current position of the wheel loader 1 acquired by the position information acquisition device 112 and information of the self-position of the loading target 300. The position estimation unit 101 can recognize the relative position of the loading target 300 with respect to the excavation target 200 from the information of the excavation target 200 acquired by the perception device 111 and the relative position of the loading target 300 with respect to the wheel loader 1.

[0150] The automation controller 100 that forms the automatic control system of the wheel loader 1 described in the above embodiment is not necessarily mounted on the wheel loader 1. A controller outside the wheel loader 1 may construct a system included in the automation controller 100. A controller mounted on the wheel loader 1 may perform processing of transmitting information acquired by the external information acquisition unit 110, the vehicle information acquisition unit 120, and the like to an external controller, and the external controller that has received a signal may generate a travel path of the wheel loader 1.

[0151] The external controller may be disposed at a work site of the wheel loader 1, or may be disposed at a remote place away from the work site of the wheel loader 1.

[0152] The external controller may be a portable device. The external controller may be a portable device that can be carried and used by a worker, such as a notebook computer, a tablet computer, or a smartphone.

[0153] In the embodiment, the dump truck is exemplified as the loading target 300, and the work of loading material loaded on the work implement 3 (bucket 6) onto the vessel 301 has been described. The loading target 300 for loading material in the bucket 6 is not limited to the vessel 301 of the dump truck, and may be, for example, a hopper.

[0154] In the embodiment, an example has been described in which the excavation target 200 and the loading target 300 are detected by the perception device 111 mounted on the wheel loader 1. An object sensor that detects an object around the main body of the wheel loader 1 (work machine main body) is not necessarily mounted on the wheel loader 1. The object sensor may be disposed outside the work machine. For example, the object sensor may be disposed at a predetermined point of the work site, may be mounted on another work machine, or may be mounted on an unmanned aerial vehicle such as a drone.

[0155] In the embodiment, an example has been described in which the wheel loader 1 includes the cab 5 and is a manned vehicle in which the operator boards the cab 5.

[0156] The wheel loader 1 may be an unmanned vehicle. The wheel loader 1 may not include the cab 5 for the operator to board and operate. The wheel loader 1 may not include a steering function by a boarded operator. The wheel loader 1 may be a work machine dedicated to remote control. The operation of the wheel loader 1 may be performed by a wireless signal from a remote control device.<Supplementary Note>

[0157] The above description includes the following features.(Supplement 1)

[0158] A system including a work machine, including:

[0159] a work machine main body including a travel body;

[0160] a work implement attached to the work machine main body;

[0161] a sensor that detects an object around the work machine main body; and

[0162] a controller that generates a travel path of the travel body, in which

[0163] the object includes an excavation target that is a heap of material excavated by the work implement and a loading target onto which the material is loaded,

[0164] the travel path includes an excavation position at which the work machine excavates the excavation target and a loading position in a case where the material is loaded onto the loading target, and

[0165] the controller recognizes the loading target on a basis of a detection result of the sensor, recognizes the loading position, and calculates a minimum distance by which the excavation position is to be separated from the loading position by a dimension of the work machine.(Supplement 2)

[0166] The system according to Supplement 1, in which a dimension of the work machine includes a dimension in a front-rear direction of the work machine.(Supplement 3)

[0167] The system according to Supplement 1 or 2, in which the travel path in a case where the work machine performs loaded backing is separated from the loading position by a distance larger than the minimum distance.(Supplement 4)

[0168] The system according to Supplement 3, in which the controller recognizes a shape of the excavation target on a basis of a detection result of the sensor, and selects the excavation position on a basis of a shape of the excavation target.(Supplement 5)

[0169] The system according to Supplement 4, in which the controller selects, as the excavation position, a position that can minimize a travel distance by which the work machine that excavates the excavation target advances toward the excavation target so as to load a certain amount of the material onto the work implement.(Supplement 6)

[0170] The system according to any one of Supplements 1 to 5, in which the controller determines a turning-back position at which the work machine is switched from loaded backing to loaded advancing by a dimension of the work machine.(Supplement 7)

[0171] The system according to any one of Supplements 1 to 6, in which the work machine main body includes a front frame and a rear frame bendable with respect to the front frame.(Supplement 8)

[0172] The system according to Supplement 7, in which the work machine takes a straight posture in which the front frame and the rear frame are not bent from each other in a case where the excavation target is excavated and in a case where the material is loaded onto the loading target.(Supplement 9)

[0173] The system according to any one of Supplements 1 to 8, in which the controller generates the travel path of the travel body that can travel without stationary steering.(Supplement 10)

[0174] The system according to any one of Supplements 1 to 9, in which the work machine is capable of executing excavation and loading work in which after the work machine excavates the excavation target, the work machine performs loaded backing, and the work machine switches advancing and backing to perform loaded advancing toward the loading target, and

[0175] the controller calculates the minimum distance in a case where the excavation and loading work is executed.

[0176] It should be understood that the embodiments disclosed herein are illustrative in all respects and not restrictive. The scope of the present invention is defined not by the above description but by the claims, and is intended to include meanings equivalent to the claims and all modifications within the scope.REFERENCE SIGNS LIST1 Wheel loader

[0178] 2 Vehicle body frame

[0179] 2a Front frame

[0180] 2b Rear frame

[0181] 3 Work implement

[0182] 4 Travel device

[0183] 4a Front wheel

[0184] 4b Rear wheel

[0185] 6 Bucket

[0186] 6a Blade edge

[0187] 6aC Center point

[0188] 6c Width direction center

[0189] 14 Boom

[0190] 50 Vehicle body controller

[0191] 60 Engine controller

[0192] 70 Transmission controller

[0193] 80 Work implement controller

[0194] 100 Automation controller

[0195] 101 Position estimation unit

[0196] 102 Path planning unit

[0197] 103 Path follow-up control unit

[0198] 110 External information acquisition unit

[0199] 111 Perception device

[0200] 120 Vehicle information acquisition unit

[0201] 150 Communication device

[0202] 200 Excavation target

[0203] 201 Top portion

[0204] 202 Skirt

[0205] 203 Low heap area

[0206] 204 Accumulation area

[0207] 300 Loading target

[0208] 301 Vessel

[0209] 306 Rear upper edge

[0210] A1 Loading position

[0211] B1 Temporary excavation position

[0212] Bx Excavation position

[0213] P Path

[0214] T1 Temporary turning-back position

[0215] Tx Turning-back position

[0216] x1 Distance.

Examples

Embodiment Construction

[0019]Hereinafter, an embodiment will be described with reference to the drawings. In the following description, the same parts and components are denoted by the same reference signs. This also applies to their names and functions. Therefore, detailed descriptions thereof will not be repeated. It is also originally planned that any configurations are extracted from the embodiment and are freely combined.

1>

[0020]In the embodiment, a wheel loader 1 will be described as an example of a work machine. FIG. 1 is a side view of the wheel loader 1 as an example of a work machine. FIG. 2 is a plan view of the wheel loader 1 illustrated in FIG. 1.

[0021]As illustrated in FIGS. 1 and 2, the wheel loader 1 mainly includes a vehicle body frame 2, a work implement 3, a travel device 4, and a cab 5. The vehicle body frame 2, the cab 5, and the like form the vehicle body of the wheel loader 1. The work implement 3 and the travel device 4 are attached to the vehicle body of the wheel loader 1. The ma...

TECHNICAL FIELD

[0001] The present disclosure relates to a system including a work machine, a controller for a work machine, and a path generation method for a work machine.BACKGROUND ART

[0002] A conventional wheel loader is disclosed in, for example, JP 2022-157259 A (Patent Literature 1).CITATION LISTPatent Literature

[0003] Patent Literature 1: JP 2022-157259 ASUMMARY OF INVENTIONTechnical Problem

[0004] A wheel loader repeatedly performs excavation work and loading work. In order to automate the excavation work and the loading work, a path of traveling by automatic control is required to be appropriately set.

[0005] The present disclosure proposes a system including a work machine, a controller for a work machine, and a path generation method for a work machine by which a path of traveling in a case where excavation and loading work is automatically controlled can be appropriately set.Solution to Problem

[0006] A system including a work machine according to an aspect of the present disclosure includes a work machine main body including a travel body, a work implement attached to the work machine main body, and a controller that generates a travel path of the travel body. An object around the work machine main body includes an excavation target that is a heap of material excavated by the work implement and a loading target onto which the material is loaded. The travel path of the travel body includes an excavation position at which the work machine excavates the excavation target and a loading position in a case where the material is loaded onto the loading target. The controller recognizes the loading target on the basis of a detection result of the sensor, recognizes the loading position, and calculates a minimum distance by which the excavation position is to be separated from the loading position by a dimension of the work machine.

[0007] A controller for a work machine according to an aspect of the present disclosure generates a travel path of a travel body of a work machine including the travel body and a work implement. The travel path of the travel body includes an excavation position at which the work machine excavates an excavation target that is a heap of material excavated by the work implement and a loading position in a case where material is loaded onto a loading target onto which the material is loaded. The controller recognizes the loading target on the basis of a detection result of a sensor that detects an object around a work machine main body. The controller recognizes the loading position. The controller calculates a minimum distance by which the excavation position is to be separated from the loading position by a dimension of the work machine.

[0008] A path generation method for a work machine according to an aspect of the present disclosure is a method for generating a travel path of a travel body of a work machine including the travel body and a work implement. The travel path of the travel body includes an excavation position at which the work machine excavates an excavation target that is a heap of material excavated by the work implement and a loading position in a case where material is loaded onto a loading target onto which the material is loaded. The path generation method includes the following steps. The first step is to recognize the loading target on the basis of a detection result of a sensor that detects an object around a work machine main body. The second step is to recognize the loading position. The third step is to calculate a minimum distance by which the excavation position is to be separated from the loading position by a dimension of the work machine.Advantageous Effects of Invention

[0009] According to a system including a work machine, a controller for a work machine, and a path generation method for a work machine of the present disclosure, a path of traveling in a case where excavation and loading work is automatically controlled can be appropriately set.BRIEF DESCRIPTION OF DRAWINGS

[0010] FIG. 1 is a side view of a wheel loader as an example of a work machine.

[0011] FIG. 2 is a plan view of the wheel loader illustrated in FIG. 1.

[0012] FIG. 3 is a view for describing excavation and loading work by the wheel loader.

[0013] FIG. 4 is a block diagram illustrating a schematic configuration of a control system of the wheel loader.

[0014] FIG. 5 is a block diagram illustrating a configuration of an automatic control system of the wheel loader.

[0015] FIG. 6 is a schematic view of a vessel of a dump truck as viewed from the side.

[0016] FIG. 7 is a schematic view illustrating a travel path of the wheel loader that performs excavation and loading work.

[0017] FIG. 8 is a flowchart illustrating a flow of processing of generating a travel path of the wheel loader.

[0018] FIG. 9 is a schematic diagram illustrating an example of a loading position with respect to a vessel.DESCRIPTION OF EMBODIMENTS

[0019] Hereinafter, an embodiment will be described with reference to the drawings. In the following description, the same parts and components are denoted by the same reference signs. This also applies to their names and functions. Therefore, detailed descriptions thereof will not be repeated. It is also originally planned that any configurations are extracted from the embodiment and are freely combined.<Overall Configuration of Wheel Loader 1>

[0020] In the embodiment, a wheel loader 1 will be described as an example of a work machine. FIG. 1 is a side view of the wheel loader 1 as an example of a work machine. FIG. 2 is a plan view of the wheel loader 1 illustrated in FIG. 1.

[0021] As illustrated in FIGS. 1 and 2, the wheel loader 1 mainly includes a vehicle body frame 2, a work implement 3, a travel device 4, and a cab 5. The vehicle body frame 2, the cab 5, and the like form the vehicle body of the wheel loader 1. The work implement 3 and the travel device 4 are attached to the vehicle body of the wheel loader 1. The main body of the wheel loader 1 (work machine main body) includes the vehicle body and the travel device 4.

[0022] The travel device 4 causes the vehicle body of the wheel loader 1 to travel, and includes travel wheels 4a and 4b. The wheel loader 1 is a wheeled vehicle including the travel wheels 4a and 4b as traveling rotation bodies on both sides of the vehicle body in a left-right direction. The wheel loader 1 is self-propelled by rotationally driving the travel wheels 4a and 4b, and can perform desired work using the work implement 3. The travel device 4 corresponds to an example of a “travel body”.

[0023] In the present specification, a direction in which the wheel loader 1 travels straight is referred to as a front-rear direction of the wheel loader 1. In the front-rear direction of the wheel loader 1, a side on which the work implement 3 is disposed with respect to the vehicle body frame 2 is defined as a front direction, and a side opposite to the front direction is defined as a rear direction. The left-right direction of the wheel loader 1 is a direction orthogonal to the front-rear direction in a plan view of the wheel loader 1 on a flat ground. The right side and the left side in the left-right direction when viewed in the front direction are the right direction and the left direction, respectively. The vertical direction of the wheel loader 1 is a direction orthogonal to a plane defined by the front-rear direction and the left-right direction. In the vertical direction, the side with the ground is the lower side, and the side with the sky is the upper side.

[0024] The vehicle body frame 2 includes a front frame 2a and a rear frame 2b. The front frame 2a is disposed in front of the rear frame 2b. The front frame 2a and the rear frame 2b are attached to each other by a center pin 10 so as to be movable in the left-right direction.

[0025] A pair of left and right steering cylinders 11 is attached across the front frame 2a and the rear frame 2b. The steering cylinders 11 are hydraulic cylinders. By the steering cylinders 11 being expanded and contracted by hydraulic oil from a steering pump (not illustrated), the travel direction of the wheel loader 1 is changed to the left and right. The front frame 2a and the rear frame 2b form the vehicle body frame 2 including an articulated structure. The wheel loader 1 is an articulated work machine in which the front frame 2a and the rear frame 2b are coupled to each other so as to be bendable.

[0026] The work implement 3 and a pair of the travel wheels (front wheels) 4a are attached to the front frame 2a. The work implement 3 is attached to the front of the vehicle body of the wheel loader 1. The work implement 3 is supported by the vehicle body of the wheel loader 1. Specifically, the work implement 3 is rotatably supported by the vehicle body frame 2, more specifically, the front frame 2a. The work implement 3 is disposed in front of the vehicle body frame 2.

[0027] The work implement 3 includes a boom 14. A base end portion of the boom 14 is rotatably attached to the front frame 2a by a boom pin 9. The boom 14 includes a left boom member 14L and a right boom member 14R. The left boom member 14L and the right boom member 14R are joined to each other so as to be unable to relatively move by a joining member that extends in the left-right direction to form the boom 14 including an integrated structure. The boom pin 9 includes a pair of a left boom pin 9L and a right boom pin 9R. The boom 14 is rotatable with respect to the front frame 2a about the left boom pin 9L and the right boom pin 9R. The left boom pin 9L and the right boom pin 9R rotatably support the work implement 3 with respect to the vehicle body frame 2.

[0028] The work implement 3 includes a bucket 6. The bucket 6 is disposed at the distal end of the work implement 3. The bucket 6 is a work tool for excavation and loading. A blade edge 6a is a distal end portion of the bucket 6. A back surface 6b is a part of the outer surface of the bucket 6. The back surface 6b includes a flat surface. The back surface 6b extends rearward from the blade edge 6a. The bucket 6 is rotatably attached to the boom 14 by a bucket pin 17 located at a distal end of the boom 14. The bucket 6 includes a left boom attachment portion to which the left boom member 14L is attached and a right boom attachment portion to which the right boom member 14R is attached.

[0029] The work implement 3 further includes a bell crank 18 and a link 15. A substantially central portion of the bell crank 18 is rotatably supported by the boom 14 by a support pin 18a located substantially at the center of the boom 14 in the longitudinal direction. The link 15 is coupled to a coupling pin 18c included at the lower end (distal end portion) of the bell crank 18. The link 15 couples the bell crank 18 and the bucket 6. The bell crank 18 and the link 15 are disposed between the left boom member 14L and the right boom member 14R in the left-right direction.

[0030] The front frame 2a and the boom 14 are coupled by a pair of boom cylinders 16. The boom cylinders 16 are hydraulic cylinders. The boom cylinders 16 drive the boom 14 to rotate up and down about the boom pin 9. The base ends of the boom cylinders 16 are attached to the front frame 2a. The distal ends of the boom cylinders 16 are attached to the boom 14. The boom cylinders 16 are hydraulic actuators that move the boom 14 up and down with respect to the front frame 2a. As the boom 14 ascends and descends, the bucket 6 attached to the distal end of the boom 14 also ascends and descends.

[0031] A bucket cylinder 19 couples the bell crank 18 and the front frame 2a. The base end of the bucket cylinder 19 is attached to the front frame 2a. The distal end of the bucket cylinder 19 is attached to a coupling pin 18b included at the upper end portion (base end portion) of the bell crank 18. The bucket cylinder 19 is a hydraulic actuator that rotates the bucket 6 up and down with respect to the boom 14. The bucket cylinder 19 is a work tool cylinder that drives the bucket 6. The bucket cylinder 19 rotationally drives the bucket 6 around the bucket pin 17. The bucket 6 is formed to be operable with respect to the boom 14. The bucket 6 is formed to be operable with respect to the front frame 2a.

[0032] The boom cylinders 16 and the bucket cylinder 19 form a work implement actuator that drives the work implement 3.

[0033] The cab 5 on which the operator boards and a pair of the travel wheels (rear wheels) 4b are attached to the rear frame 2b. The box-shaped cab 5 is disposed behind the boom 14. The cab 5 is mounted on the rear frame 2b. The cab 5 is placed on the vehicle body frame 2. In the cab 5, a seat on which the operator of the wheel loader 1 sits, an operation device 8 to be described below, and the like are disposed.

[0034] A perception device 111 is included on the cab 5. The perception device 111 is disposed, for example, on a ceiling of the cab 5. The perception device 111 is mounted on, for example, an upper surface of the cab 5. The perception device 111 is disposed, for example, on a front portion of the cab 5. The perception device 111 is attached to the cab 5 facing forward, for example, and can acquire information of the front of the cab 5. Details of the perception device 111 will be described below.

[0035] A length L1 illustrated in FIG. 1 is a length from the blade edge 6a of the bucket 6 to the rear end of the vehicle body (total length of the wheel loader 1) in the front-rear direction. A length L2 is a length from the front end of the front wheel 4a to the rear end of the vehicle body in the front-rear direction (vehicle body length of the wheel loader 1). A length L3 is a length (wheelbase length) from the center of the front wheel 4a to the center of the rear wheel 4b in the front-rear direction. A length LA is a length from the center of the front wheel 4a to the bending center of the front frame 2a and the rear frame 2b in the front-rear direction. A length L5 is a length from the bending center of the front frame 2a and the rear frame 2b to the center of the rear wheel 4b in the front-rear direction.

[0036] A length L9 illustrated in FIG. 2 is a length (bucket width) from the left end to the right end of the bucket 6 in the left-right direction. A width direction center 6c of the bucket 6 is a center point of the bucket 6 in the left-right direction.

[0037] Lengths L1 to L5 and L9 illustrated in FIGS. 1 and 2 are included in a specification value of the wheel loader 1. The specification value of the wheel loader 1 further includes a minimum turning radius of the vehicle body. The wheel loader 1 includes an articulated structure in which the front frame 2a and the rear frame 2b are bendable from each other, so that the minimum turning radius of the vehicle body is smaller as compared to a rigid structure. The specification value of the wheel loader 1 is a value unique to each individual of the wheel loader 1, and is stored in a vehicle body controller 50 to be described below.<Excavation and Loading Work>

[0038] The wheel loader 1 according to the present embodiment executes excavation and loading work of scooping material into the bucket 6 and loading the material in the bucket 6 onto a loading target such as a dump truck. The material is earth, sand, rock, ore, or the like excavated at a work site or carried into the work site by a carrying machine such as a dump truck. FIG. 3 is a view for describing excavation and loading work by the wheel loader 1 according to the embodiment.

[0039] FIG. 3(A) illustrates the wheel loader 1 that performs unloaded advancing. The wheel loader 1 travels forward toward an excavation target 200 that is a heap of material. The boom cylinders 16 and the bucket cylinder 19 are operated so that the work implement 3 is in an excavation posture in which the distal end of the boom 14 is at a low position and the bucket 6 is oriented horizontally.

[0040] FIG. 3(B) and 3(C) illustrate the wheel loader 1 performing excavation work. The wheel loader 1 thrusts the blade edge 6a of the bucket 6 into the excavation target 200, and stops forward travel. The blade edge 6a of the bucket 6 bites into the excavation target 200 by an excavation (thrusting) operation illustrated in FIG. 3(B). In this state, when the boom 14 and the bucket 6 rise and the bucket 6 tilts back, the bucket 6 moves along a bucket trajectory BL as indicated by an arrow in FIG. 3(C). With this operation, an excavation (scooping) operation of scooping the excavation target 200 into the bucket 6 illustrated in FIG. 3(C) is executed.

[0041] Depending on the type of the excavation target 200, the excavation (scooping) operation may be completed only by tilting back the bucket 6 once. Alternatively, in the excavation (scooping) operation, the operation of tilting back, neutralizing, and tilting back the bucket 6 again may be repeated.

[0042] FIG. 3(D) illustrates the wheel loader 1 that performs loaded backing. The wheel loader 1 travels backward with the excavation target 200 loaded in the bucket 6. The wheel loader 1 may raise the bucket 6 while traveling backward.

[0043] FIG. 3(E) illustrates the wheel loader 1 that performs loaded advancing. The wheel loader 1 travels forward toward a loading target 300 while raising the bucket 6 or maintaining a state in which the bucket 6 is raised. The wheel loader 1 approaches the loading target 300 until the bucket 6 reaches a predetermined position located substantially directly above the loading platform of the loading target 300.

[0044] FIG. 3(F) illustrates the wheel loader 1 that performs a soil discharging operation to the loading target 300. When the wheel loader 1 approaches the loading target 300 and reaches a predetermined position, the wheel loader 1 dumps the bucket 6 and loads the material in the bucket 6 onto the loading target 300. Thereafter, the wheel loader 1 lowers the boom 14 to return the work implement 3 to the excavation posture while traveling backward to the position at which the forward travel is started in FIG. 3(E).

[0045] The above is a typical operation included in one cycle of the excavation and loading work. The wheel loader 1 repeatedly performs the plurality of operations described above in sequence, excavates the excavation target 200, and loads the excavated material onto the loading target 300 such as a dump truck.

[0046] When excavating the excavation target 200 illustrated in FIG. 3(B) and 3(C), the wheel loader 1 takes a straight posture in which the front frame 2a and the rear frame 2b are not bent from each other. When loading the material in the bucket 6 illustrated in FIG. 3(F) onto the loading target 300, the wheel loader 1 takes a straight posture in which the front frame 2a and the rear frame 2b are not bent from each other.<System Configuration>

[0047] FIG. 4 is a block diagram illustrating a schematic configuration of a control system that controls the wheel loader 1.

[0048] An engine 21 is a driving source that generates a driving force for driving the work implement 3 and the travel device 4, and is, for example, a diesel engine. As the driving source, instead of the engine 21, a motor driven by a power storage body may be used, or both the engine and the motor may be used. The output of the engine 21 is controlled by adjusting the amount of fuel injected into the cylinder of the engine 21.

[0049] The driving force generated by the engine 21 is transmitted to a transmission 23. The transmission 23 shifts the driving force to an appropriate torque and rotational speed. An axle 25 is connected to an output shaft of the transmission 23. The driving force shifted by the transmission 23 is transmitted to the axle 25. The driving force is transmitted from the axle 25 to the travel wheels 4a and 4b (FIGS. 1 and 2). Thus, the wheel loader 1 travels. In the wheel loader 1 of the embodiment, both the travel wheel 4a and the travel wheel 4b form driving wheels that receive a driving force and cause the wheel loader 1 to travel.

[0050] A part of the driving force of the engine 21 is transmitted to a work implement pump 13. The work implement pump 13 is a hydraulic pump that is driven by the engine 21 and operates the work implement 3 by discharged hydraulic oil. The work implement 3 is driven by hydraulic oil from the work implement pump 13. The hydraulic oil discharged from the work implement pump 13 is supplied to the boom cylinders 16 and the bucket cylinder 19 via a main valve 32. When the boom cylinders 16 expand and contract by receiving the supply of the hydraulic oil, the boom 14 moves up and down. When the bucket cylinder 19 receives the supply of the hydraulic oil and expands and contracts, the bucket 6 rotates up and down.

[0051] The wheel loader 1 includes the vehicle body controller 50. The vehicle body controller 50 includes an engine controller 60, a transmission controller 70, and a work implement controller 80.

[0052] The vehicle body controller 50 is generally implemented by reading various programs by a central processing unit (CPU). The vehicle body controller 50 includes a memory (not illustrated). The memory functions as a work memory and stores various programs for implementing the function of the wheel loader 1.

[0053] The operation device 8 is included in the cab 5. The operation device 8 is operated by the operator. The operation device 8 includes a plurality of types of operation members operated by the operator to operate the wheel loader 1. The operation device 8 includes an accelerator pedal 41 and a work implement operation lever 42. The operation device 8 may include a steering wheel, a shift lever, and the like (not illustrated).

[0054] The accelerator pedal 41 is operated to set a target rotation speed of the engine 21. The engine controller 60 controls the output of the engine 21 on the basis of the operation amount of the accelerator pedal 41. When the operation amount (depression amount) of the accelerator pedal 41 is increased, the output of the engine 21 is increased. When the operation amount of the accelerator pedal 41 is reduced, the output of the engine 21 is reduced. The transmission controller 70 controls the transmission 23 on the basis of the operation amount of the accelerator pedal 41.

[0055] The work implement operation lever 42 is operated to operate the work implement 3. The work implement controller 80 controls electromagnetic proportional control valves 35 and 36 on the basis of the operation amount of the work implement operation lever 42.

[0056] The electromagnetic proportional control valve 35 contracts the bucket cylinder 19 to switch the main valve 32 such that the bucket 6 moves in the dumping direction (direction in which the blade edge of the bucket 6 is lowered). Furthermore, the electromagnetic proportional control valve 35 extends the bucket cylinder 19 to switch the main valve 32 such that the bucket 6 moves in the tilting direction (direction in which the blade edge of the bucket 6 is raised). The electromagnetic proportional control valve 36 contracts the boom cylinders 16 to switch the main valve 32 such that the boom 14 is lowered. Furthermore, the electromagnetic proportional control valve 36 extends the boom cylinders 16 to switch the main valve 32 such that the boom 14 is raised.

[0057] A machine monitor 51 receives input of an instruction signal from the vehicle body controller 50 and displays various types of information. The various types of information displayed on the machine monitor 51 may be, for example, information regarding work executed by the wheel loader 1, vehicle body information such as a remaining amount of fuel, a cooling water temperature, and a hydraulic oil temperature, a peripheral image obtained by imaging the periphery of the wheel loader 1, and the like. The machine monitor 51 may be a touch panel, and in this case, a signal generated by the operator touching a part of the machine monitor 51 is output from the machine monitor 51 to the vehicle body controller 50.<Automatic Control System of Wheel Loader 1>

[0058] In automating work of the wheel loader 1, an operation of a skilled operator is desirably reproduced by automatic control. FIG. 5 is a block diagram illustrating a configuration of an automatic control system of the wheel loader 1.

[0059] An automation controller 100 is formed to be able to transmit and receive signals to and from the vehicle body controller 50 described with reference to FIG. 4.

[0060] The automation controller 100 is also formed to be able to transmit and receive signals to and from an external information acquisition unit 110. The external information acquisition unit 110 includes the perception device 111 and a position information acquisition device 112. The perception device 111 and the position information acquisition device 112 are mounted on the wheel loader 1.

[0061] The perception device 111 acquires information of the surroundings of the wheel loader 1. The perception device 111 is attached to a front portion of the upper surface of the cab 5, for example. The perception device 111 corresponds to an example of an “object sensor” that detects an object around the main body of the wheel loader 1 (work machine main body).

[0062] The perception device 111 detects a direction of an object outside the wheel loader 1 and a distance to the object in a non-contact manner. The perception device 111 is, for example, a light detection and ranging (LiDAR) that emits laser light and acquires information of an object. The perception device 111 may be a visual sensor including a camera. The perception device 111 may be a radio detection and ranging (Radar) that acquires information of an object by emitting radio waves. The perception device 111 may be an infrared sensor.

[0063] The position information acquisition device 112 acquires information of the current position of the wheel loader 1. The position information acquisition device 112 acquires position information of the wheel loader 1 in a global coordinate system with reference to the earth using, for example, a satellite positioning system. The position information acquisition device 112 uses, for example, global navigation satellite systems (GNSS), and includes a GNSS receiver. The satellite positioning system calculates the position of the antenna of the GNSS receiver from a positioning signal received by the GNSS receiver from a satellite to calculate the position of the wheel loader 1.

[0064] External information of the wheel loader 1 by the perception device 111 and the position information of the wheel loader 1 by the position information acquisition device 112 are input to the automation controller 100.

[0065] The vehicle body controller 50 is formed to be able to transmit and receive signals to and from a vehicle information acquisition unit 120, and receives input of information of the wheel loader 1 acquired by the vehicle information acquisition unit 120. The vehicle information acquisition unit 120 includes various sensors mounted on the wheel loader 1. The vehicle information acquisition unit 120 includes an articulation angle sensor 121, a vehicle speed sensor 122, a boom angle sensor 123, a bucket angle sensor 124, and a boom cylinder pressure sensor 125.

[0066] The articulation angle sensor 121 detects an articulation angle that is an angle formed by the front frame 2a and the rear frame 2b, and generates a signal of the detected articulation angle. The articulation angle sensor 121 outputs the signal of the articulation angle to the vehicle body controller 50.

[0067] The vehicle speed sensor 122 detects the moving speed of the wheel loader 1 by the travel device 4, for example, by detecting the rotation speed of the output shaft of the transmission 23, and generates a signal of the detected vehicle speed. The vehicle speed sensor 122 outputs the signal of the vehicle speed to the vehicle body controller 50. The vehicle speed sensor 122 corresponds to an example of a travel sensor that detects a traveling status of the travel device 4 (travel body).

[0068] The boom angle sensor 123 includes, for example, a rotary encoder included in the boom pin 9 that is an attachment portion of the boom 14 to the vehicle body frame 2. The boom angle sensor 123 detects an angle of the boom 14 with respect to the horizontal direction (boom angle), and generates a signal indicating the detected angle of the boom 14. The boom angle sensor 123 outputs the signal of the angle of the boom 14 to the vehicle body controller 50.

[0069] The bucket angle sensor 124 includes, for example, a rotary encoder included in the support pin 18a that is a rotation shaft of the bell crank 18. The bucket angle sensor 124 detects an angle of the bell crank 18 with respect to the boom 14 (bell crank angle), and generates a signal of the detected angle of the bell crank 18. The vehicle information acquisition unit 120 or the vehicle body controller 50 calculates an angle of the bucket 6 (bucket angle) with respect to the boom 14 from the detected angle of the bell crank 18.

[0070] The boom angle sensor 123 and the bucket angle sensor 124 correspond to an example of a work implement posture sensor that detects the posture of the work implement 3. The boom angle sensor 123 may be a stroke sensor disposed on the boom cylinder 16. The bucket angle sensor 124 may be a potentiometer or a proximity switch attached to the bucket pin 17, or may be a stroke sensor disposed on the bucket cylinder 19.

[0071] The boom cylinder pressure sensor 125 detects pressure on the bottom side (boom bottom pressure) of the boom cylinder 16, and generates a signal of the detected boom bottom pressure. The boom bottom pressure increases in a case where a load is loaded on the bucket 6, and decreases in a case where the load is empty. The boom cylinder pressure sensor 125 outputs the signal of the boom bottom pressure to the vehicle body controller 50.

[0072] The vehicle body controller 50 outputs information input from the vehicle information acquisition unit 120 to the automation controller 100. The automation controller 100 receives detection values of the vehicle speed sensor 122, the boom angle sensor 123, and the bucket angle sensor 124 via the vehicle body controller 50.

[0073] An actuator 140 is formed to be able to transmit and receive signals to and from the vehicle body controller 50. The actuator 140 is driven upon receiving an instruction signal from the vehicle body controller 50. The actuator 140 includes a brake electromagnetic proportional control valve (EPC) 141 for operating the brake of the travel device 4, a steering EPC 142 for adjusting the traveling direction of the wheel loader 1, a work implement EPC 143 for operating the work implement 3, and a hydraulic mechanical transmission (HMT) 144.

[0074] The electromagnetic proportional control valves 35 and 36 illustrated in FIG. 4 form the work implement EPC 143. The transmission 23 illustrated in FIG. 4 is implemented as the HMT 144 utilizing electronic control. The transmission 23 may be a hydro-static transmission (HST). A power transmission device that transmits power from the engine 21 to the travel wheels 4a and 4b may include an electric drive device of a diesel electric type or the like, or may include any combination of the HMT, the HST, and the electric drive device.

[0075] The transmission controller 70 includes a brake control unit 71 and an accelerator control unit 72. The brake control unit 71 outputs an instruction signal for controlling the operation of the brake to the brake EPC 141. The accelerator control unit 72 outputs an instruction signal for controlling the vehicle speed to the HMT 144.

[0076] The work implement controller 80 includes a steering control unit 81 and a work implement control unit 82. The steering control unit 81 outputs an instruction signal for controlling the traveling direction of the wheel loader 1 to the steering EPC 142. The work implement control unit 82 outputs an instruction signal for controlling the operation of the work implement 3 to the work implement EPC 143.

[0077] The automation controller 100 includes a position estimation unit 101, a path planning unit 102, and a path follow-up control unit 103.

[0078] The position estimation unit 101 estimates the self-position of the wheel loader 1 on the basis of the position information acquired by the position information acquisition device 112. Furthermore, the position estimation unit 101 recognizes a target position on the basis of the external information acquired by the perception device 111. The target position is, for example, an excavation position in the excavation target 200 at which the wheel loader 1 excavates the excavation target 200 using the bucket 6. Further, for example, the target position is a loading position in the loading target 300 that is a relative position of the work implement 3 (bucket 6) with respect to the loading target 300 when material is loaded onto the loading target 300. The perception device 111 may recognize and input a target position to the automation controller 100, and the position estimation unit 101 may recognize a target position on the basis of the detection result detected by the perception device 111.

[0079] The path planning unit 102 generates an optimum path of the wheel loader 1 in a case where the wheel loader 1 is automatically controlled. The optimum path includes a path of traveling by the travel device 4 and a path of operation of the work implement 3.

[0080] For example, the path planning unit 102 generates a path of traveling of the wheel loader 1 that performs unloaded advancing toward the excavation target 200.

[0081] The path planning unit 102 generates a path of the operation of the work implement 3 in excavation work. The path planning unit 102 generates a path of traveling of the wheel loader 1 that performs loaded backing to be separated from the excavation target 200 and a path of operation of the work implement 3 that is performing loaded backing. The path planning unit 102 generates a path of traveling of the wheel loader 1 that performs loaded advancing toward the loading target 300 and a path of operation of the work implement 3 that is performing loaded advancing. The path planning unit 102 generates a path of operation of the work implement 3 that discharges material scooped into the bucket 6 to the loading target 300. The path planning unit 102 generates a path of traveling of the wheel loader 1 that performs unloaded backing to be separated from the loading target 300 and a path of operation of the work implement 3 that is performing unloaded backing.

[0082] The path planning unit 102 also generates an optimum path that connects the current self-position of the wheel loader 1 and a target position to which the wheel loader 1 is heading while executing the excavation and loading work.

[0083] The path follow-up control unit 103 gives an instruction of operation of the travel device 4 and the work implement 3. The path follow-up control unit 103 controls the accelerator, the brake, and the steering such that the wheel loader 1 travels following the optimum path generated by the path planning unit 102. An instruction signal for causing the wheel loader 1 to travel along the optimum path is output from the path follow-up control unit 103 to the brake control unit 71, the accelerator control unit 72, and the steering control unit 81. The path follow-up control unit 103 controls the boom cylinders 16 and the bucket cylinder 19 such that the work implement 3 operates along the optimum path generated by the path planning unit 102. An instruction signal for moving the work implement 3 along the optimum path is output from the path follow-up control unit 103 to the work implement control unit 82.

[0084] An interface 130 is formed to be able to transmit and receive signals to and from the vehicle body controller 50. The interface 130 includes an automation switching switch 131, an engine emergency stop switch 132, and a mode lamp 133.

[0085] The automation switching switch 131 is operated by the operator. The operator operates the automation switching switch 131 to switch between manually operating the wheel loader 1 and automatically controlling the wheel loader 1. The engine emergency stop switch 132 is operated by the operator. In a case where an event that requires emergency stop of the engine 21 occurs, the operator operates the engine emergency stop switch 132. Operation signals of the automation switching switch 131 and the engine emergency stop switch 132 are input to the vehicle body controller 50.

[0086] The mode lamp 133 displays whether the wheel loader 1 is currently in a mode of being manually operated by the operator or in a mode of being automatically controlled. An instruction signal for controlling lighting of the lamp is output from the vehicle body controller 50 to the mode lamp 133.

[0087] The automation controller 100 is also formed to be able to transmit and receive signals to and from a communication device 150. The automatic control system of the wheel loader 1 is formed to be able to gives an instruction of information held by the automation controller 100 to the loading target 300 such as a dump truck via the communication device 150.<Vessel 301>

[0088] The dump truck as an example of the loading target 300 includes a vessel 301. The vessel 301 is an example of a container in which material loaded on the work implement 3 (bucket 6) is loaded. FIG. 6 is a schematic view of the vessel 301 of the dump truck as viewed from the side. In FIG. 6 and subsequent FIG. 9, a schematic shape of the vessel 301 viewed from the left side of the dump truck is illustrated. A thick line in the drawing indicates a schematic shape when a surface that forms the internal shape of the vessel 301 is viewed from the left side of the dump truck.

[0089] In FIGS. 6 and 9, the left-right direction in the drawings corresponds to the front-rear direction of the dump truck (front-rear direction of the vessel 301). In FIGS. 6 and 9, the left direction in the drawing is the front direction of the dump truck (vessel 301), and the right direction in the drawing is the rear direction of the dump truck (vessel 301). In FIGS. 6 and 9, the direction perpendicular to the drawing corresponds to the left-right direction of the dump truck (left-right direction of the vessel 301). In FIGS. 6 and 9, the vertical direction in the drawing corresponds to the vertical direction of the dump truck (vertical direction of the vessel 301).

[0090] The vessel 301 is included at a rear portion of the dump truck. A cab is included in front of the dump truck, and the vessel 301 is disposed behind the cab.

[0091] The vessel 301 includes a structure in which heavy material including earth and sand, crushed stones, and the like can be loaded.

[0092] As illustrated in FIG. 6, the vessel 301 includes a bottom surface 302, a front wall surface 303, and a rear inclined surface 305. The bottom surface 302 has a flat shape. The bottom surface 302 has a planar shape that extends in the front-rear direction and the left-right direction of the dump truck (vessel 301).

[0093] The front wall surface 303 has a flat shape. The front wall surface 303 extends forward and upward from the front end of the bottom surface 302. The front wall surface 303 extends upward, being inclined toward the front. The front wall surface 303 forms a front wall surface of the vessel 301. The wall surface in front of the vessel 301 is inclined upward toward the front. The front wall surface 303 includes a front upper edge 304. The front upper edge 304 extends in the left-right direction. The front upper edge 304 forms a front edge of the vessel 301.

[0094] The rear inclined surface 305 has a flat shape. The rear inclined surface 305 extends rearward and upward from the rear end of the bottom surface 302. The rear inclined surface 305 extends upward, being inclined toward the rear. The rear inclined surface 305 is inclined upward toward the rear. The rear inclined surface 305 includes a rear upper edge 306. The rear upper edge 306 extends in the left-right direction.

[0095] The rear upper edge 306 forms a rear edge of the vessel 301. The rear upper edge 306 is located lower than the front upper edge 304.

[0096] FIG. 6 illustrates a shape of the vessel 301 without a tailgate. In a case where the vessel 301 includes a tailgate, the tailgate is disposed to extend upward from the rear end of the rear inclined surface 305. The upper edge of the tailgate forms the rear upper edge 306.<Travel Path Generation Processing in Case of Automatic Excavation and Loading Work>

[0097] Processing of generating a path of traveling of the wheel loader 1 in a case where the excavation and loading work described with reference to FIG. 3 is automatically controlled will be described below. FIG. 7 is a schematic view illustrating a travel path of the wheel loader 1 that performs the excavation and loading work. FIG. 8 is a flowchart illustrating a flow of processing of generating a travel path of the wheel loader 1.

[0098] The excavation target 200 illustrated in FIG. 7 is a heap of material excavated by the bucket 6 of the wheel loader 1. The excavation target 200 may be a heap of material accumulated in a material accumulation place such as a stockyard. The excavation target 200 may be a heap of material formed in a vacant lot. The excavation target 200 includes a top portion 201 having the highest heap height and a skirt 202 on a front side (side on which the wheel loader 1 excavates the excavation target 200. A lower side in FIG. 7). The skirt 202 is schematically illustrated linearly. The heap height of the excavation target 200 is not uniform, and the heap height gradually decreases from the top portion 201 toward the skirt 202.

[0099] In the vicinity of the skirt 202, the excavation target 200 includes a low heap area 203 in which the accumulation amount of material is small and the heap height is low, and an accumulation area 204 in which the accumulation amount of material is larger than the low heap area 203 and the heap height is higher than the low heap area 203.

[0100] As illustrated in FIG. 8, first, in step S11, the loading target 300 such as a dump truck stops at any place with respect to the excavation target 200. The loading target 300 basically stops at a stop position following rules of the work site, but may stop at any stop position different from the stop position following the rules of the work site by determination of an operator who operates the loading target 300 or by an instruction of control for monitoring the work site.

[0101] In step S12, the perception device 111 mounted on the wheel loader 1 detects the excavation target 200 and the loading target 300. The object around the wheel loader 1 detected by the perception device 111 includes the excavation target 200 and the loading target 300. The perception device 111 inputs the detection result of the excavation target 200 and the loading target 300 to the position estimation unit 101 of the automation controller 100.

[0102] The position estimation unit 101 recognizes the excavation target 200 and the loading target 300 on the basis of the detection result of the perception device 111.

[0103] The position estimation unit 101 recognizes the position and shape of a heap of material that is the excavation target 200. The position estimation unit 101 recognizes the position and shape of the vessel 301 of the loading target 300. The position estimation unit 101 recognizes an angle θ1 formed by the skirt 202 of the excavation target 200 and the left side surface of the vessel 301.

[0104] In step S13, the path planning unit 102 of the automation controller 100 recognizes a loading position A1 that is a relative position of the work implement 3 (bucket 6) with respect to the loading target 300 when material is loaded onto the loading target 300 in the loading target 300 such as a dump truck.

[0105] FIG. 9 is a schematic diagram illustrating an example of the loading position A1 with respect to the vessel 301. FIG. 9 schematically illustrates the vessel 301 viewed from the left side of the loading target 300. FIG. 9 also schematically illustrates the bucket 6 viewed from the rear of the wheel loader 1 (viewed in the front direction). The bucket 6 includes the blade edge 6a that extends in the width direction. A center point 6aC is a center point of the blade edge 6a in the width direction of the bucket 6.

[0106] The bucket 6 illustrated in FIG. 9 is in a full dump posture. The bucket 6 in the posture illustrated in FIG. 9 moves in the dumping direction to the maximum. When the bucket 6 is in the posture illustrated in FIG. 9, the cylinder stroke length of the bucket cylinder 19 is minimized.

[0107] As illustrated in FIG. 7, the wheel loader 1 travels forward from the side (left side) of the loading target 300 toward the vessel 301 and performs the loading work.

[0108] The width direction of the bucket 6 during the loading work coincides with the front-rear direction (in FIG. 9, left-right direction in the drawing) of the loading target 300 (vessel 301). Since the wheel loader 1 takes a straight posture during the loading work, the left-right direction of the wheel loader 1 coincides with the width direction of the bucket 6.

[0109] FIG. 9 illustrates material M loaded from the bucket 6 onto the vessel 301 of the loading target 300. The path planning unit 102 recognizes the position of the upper end of the left side surface of the vessel 301 corresponding to the center point 6aC of the blade edge 6a of the bucket 6 in the front-rear direction of the loading target 300 in a case where the material M loaded onto the vessel 301 does not spill from the vessel 301 as the loading position A1.

[0110] The loading position A1 is set as a position at which the right end of the bucket 6 is separated from the rear upper edge 306 of the vessel 301 by a predetermined distance when the bucket 6 in the full dump posture is viewed from the rear of the wheel loader 1 (viewed in the forward direction). The relative position of the right end of the bucket 6 with respect to the center point 6aC of the blade edge 6a is calculated from the dimension in the width direction of the bucket 6. In a case where the bucket 6 is at the loading position A1, the right end of the bucket 6 is separated forward from the rear upper edge 306 by a predetermined distance in the front-rear direction of the loading target 300.

[0111] Specifically, the path planning unit 102 determines the loading position A1 at a position at which the material M does not spill from the vessel 301 when the material M is loaded onto the vessel 301 at the angle of repose. For example, the angle of repose 30° of sand can be used for determining the loading position A1 such that the angle formed by the material M with respect to the front-rear direction of the loading target 300 at the rear upper edge 306 (FIG. 6) is 30° or less.

[0112] In step S14, the path planning unit 102 calculates a minimum distance x1 at which the wheel loader 1 can perform V-shape traveling from the specification value of the wheel loader 1. The V-shape traveling is a typical path of traveling in a case where the wheel loader 1 performs the excavation and loading work, and the travel path of the wheel loader 1 has a V-shape. In a case where the wheel loader 1 performs V-shape traveling to perform the excavation and loading work, the travel path is assumed to be efficient since the travel distance of the wheel loader 1 is minimized.

[0113] Referring to FIGS. 3 and 7, after excavating the excavation target 200, the wheel loader 1 is switched from forward movement to backward movement, and performs loaded backing. The wheel loader 1 is switched from backward movement to forward movement, and performs loaded advancing toward the loading position A1 of the loading target 300. A position at which the operation of the wheel loader 1 is switched from the loaded backing to the loaded advancing is referred to as a turning-back position. The wheel loader 1 that performs the loaded backing may travel straight from the excavation target 200 to the turning-back position. At least a part of the path on which the wheel loader 1 that performs the loaded advancing travels toward the loading position A1 of the loading target 300 may have a curved shape, typically an arc shape.

[0114] The specification value of the wheel loader 1 includes the lengths L1 to L5 and L9 of respective parts of the wheel loader 1 described with reference to FIGS. 1 and 2. As described with reference to FIG. 1, the length L1 is the total length of the wheel loader 1, and is the dimension of the wheel loader 1 in the front-rear direction. The specification value of the wheel loader 1 also includes a minimum radius in which the wheel loader 1 can turn without stationary steering in which steering is performed while the wheel loader 1 is stopped.

[0115] When loading the material in the bucket 6 onto the vessel 301 of the loading target 300, the wheel loader 1 takes a straight posture in which the front frame 2a and the rear frame 2b are not bent from each other. In a case where the material in the bucket 6 is loaded onto the vessel 301 of the loading target 300, the wheel loader 1 takes a posture in which the width direction of the bucket 6 coincides with the front-rear direction of the loading target 300 and the width direction center 6c (FIG. 2) of the bucket 6 is adjusted to the loading position A1.

[0116] As illustrated in FIG. 7, the path planning unit 102 can set a position at which the center point 6aC (FIG. 9) of the blade edge 6a of the bucket 6 is separated by the length L1 from the left side surface of the vessel 301 in the left-right direction of the loading target 300 and the center point 6aC of the blade edge 6a is separated by the length L1 from the skirt 202 of the excavation target 200 as a temporary turning-back position T1.

[0117] The dimension of the wheel loader 1 for determining the temporary turning-back position T1 is not limited to the length L1. The work implement 3 can change its posture with respect to the vehicle body of the wheel loader 1, and the length L1 may vary with movement of the work implement 3. The length L1 may vary by replacing the bucket 6. On the other hand, the length L2 that is an example of the main body dimension of the wheel loader 1 is a dimension in the front-rear direction of the wheel loader 1, and is a constant dimension regardless of the work implement 3. The path planning unit 102 may determine the temporary turning-back position T1 on the basis of the length L2.

[0118] The path planning unit 102 sets a curved path P that smoothly connects the width direction center 6c (that is, loading position A1) of the bucket 6 in a case where the wheel loader 1 takes a posture of loading the material in the bucket 6 onto the loading target 300 and the width direction center 6c of the bucket 6 in a case where the wheel loader 1 is at the temporary turning-back position T1.

[0119] The path planning unit 102 confirms that the wheel loader 1 traveling along the path P can travel without stationary steering. If the path planning unit 102 determines that stationary steering is necessary for causing the wheel loader 1 to travel along the path P, the path planning unit can reset a position separated farther from the left side surface of the vessel 301 as a temporary turning-back position.

[0120] For example, the path planning unit 102 may reset, as the temporary turning-back position, a position obtained by translating the temporary turning-back position T1 illustrated in FIG. 7 in an extending direction of the skirt 202 of the excavation target 200, the direction being away from the loading target 300 (right direction in FIG. 7).

[0121] The path planning unit 102 again sets a path that smoothly connects the reset temporary turning-back position and the loading position A1, and can repeatedly confirm whether the wheel loader 1 traveling along the path can travel without stationary steering.

[0122] The path planning unit 102 sets the path P such that the wheel loader 1 traveling along the path P can turn without stationary steering. The wheel loader 1 that travels along the path P turns in a turning radius larger than a minimum radius in which the wheel loader 1 can turn without stationary steering. The path P is a trajectory followed by the width direction center 6c of the bucket 6 in a case where the wheel loader 1 turns in a turning radius in which the wheel loader 1 can turn without stationary steering.

[0123] The path planning unit 102 can set a distance from the loading position A1 to the temporary turning-back position T1 in the extending direction of the skirt 202 of the excavation target 200 (left-right direction in FIG. 7) as a distance x1. A position to which the width direction center 6c (FIG. 2) of the bucket 6 to be directed in the extending direction of the skirt 202 of the excavation target 200 when the wheel loader 1 excavates the excavation target 200 is defined as an excavation position. The distance x1 is set as the minimum distance by which the excavation position at which the wheel loader 1 excavates the excavation target 200 is to be separated from the loading position A1 recognized as the position at which material is loaded onto the loading target 300.

[0124] In step S15, the path planning unit 102 sets the position of the skirt 202 separated from the loading position A1 by the distance x1 in the extending direction of the skirt 202 of the excavation target 200 as a temporary excavation position B1.

[0125] In step S16, the path planning unit 102 selects an excavation position Bx at a position separated farther from the loading target 300 than the temporary excavation position B1 in the extending direction of the skirt 202 of the excavation target 200.

[0126] The path planning unit 102 selects the excavation position Bx at a position separated from the loading position A1 by a distance greatly larger than the distance x1. The temporary excavation position B1 is a position at which the distance to the loading position A1 can be set to the minimum distance x1, and the excavation target 200 may be excavated at a position separated farther from the loading target 300 than the temporary excavation position B1. The distance between the excavation position Bx and the loading position A1 may be larger than the distance x1.

[0127] The path planning unit 102 recognizes the shape of the excavation target 200 on the basis of a detection result of the perception device 111. The path planning unit 102 can select the excavation position Bx on the basis of the shape of the excavation target 200. The path planning unit 102 can select, as the excavation position Bx, a distance that can minimize a travel distance by which the wheel loader 1 that excavates the excavation target 200 advances toward the excavation target 200 so as to scoop material into the bucket 6 and load a certain amount of the material onto the work implement 3, typically, so as to fully load the material into the bucket 6.

[0128] In the example illustrated in FIG. 7, the excavation target 200 includes the low heap area 203 and the accumulation area 204 in the vicinity of the skirt 202. The wheel loader 1 can scoop more material into the bucket 6 with a short travel distance by traveling forward toward the accumulation area 204 and excavating the excavation target 200 rather than traveling forward toward the low heap area 203 and excavating the excavation target 200. The wheel loader 1 travels forward toward the accumulation area 204 and excavates the excavation target 200, so that the bucket 6 can be filled with the material at a position closer to the skirt 202. Therefore, the path planning unit 102 can select a substantially central position of the accumulation area 204 in the extending direction of the skirt 202 as the excavation position Bx.

[0129] In the example illustrated in FIG. 7, the accumulation area 204 is located at a position separated farther from the loading target 300 than the temporary excavation position B1, and a position corresponding to the accumulation area 204 can be selected as the excavation position Bx. In a case where the accumulation area 204 is located closer to the loading target 300 than the temporary excavation position B1, the position corresponding to the accumulation area 204 cannot be selected as the excavation position Bx. In this case, another position separated farther from the loading target 300 than the temporary excavation position B1 is selected as the excavation position Bx.

[0130] In step S17, the path planning unit 102 generates the shortest path that connects the loading position A1 and the excavation position Bx. The path planning unit 102 can determine a position separated from the skirt 202 of the excavation target 200 by the length L1 using the excavation position Bx as a starting point as a turning-back position Tx. The path planning unit 102 can generate a path of a straight line that connects the excavation position Bx and the turning-back position Tx as a path of unloaded advancing of the wheel loader 1 toward the excavation target 200 and as a path of loaded backing of the wheel loader 1 away from the excavation target 200.

[0131] The travel path when the wheel loader 1 performs unloaded advancing and when the wheel loader 1 performs loaded backing is separated from the loading position A1 by a distance greatly larger than the distance x1.

[0132] The path planning unit 102 can generate a path obtained by combining a straight line and a curve having any curvature such that the wheel loader 1 that starts performing loaded advancing from the turning-back position Tx causes the center point 6aC of the blade edge 6a of the bucket 6 to reach the loading position A1 of the loading target 300, and the width direction of the bucket 6 when the center point 6aC reaches the loading position A1 coincides with the front-rear direction of the loading target 300. Since the curvature radius of the curve included in this path is larger than the minimum radius in which the wheel loader 1 can turn without stationary steering, the wheel loader 1 can travel forward from the turning-back position Tx to the loading position A1 without stationary steering. The path planning unit 102 can set the generated path as a path for loaded advancing of the wheel loader 1 toward the loading target 300 and a path for unloaded backing of the wheel loader 1 away from the loading target 300.

[0133] By a position separated from the loading position A1 by a distance greatly larger than the distance x1 being set as the turning-back position Tx, the wheel loader 1 that performs loaded advancing from the turning-back position Tx toward the loading position A1 can make the width direction of the bucket 6 coincide with the front-rear direction of the loading target 300 when the bucket 6 reaches the loading position A1 without stationary steering.

[0134] The path planning unit 102 may generate a path such that the wheel loader 1 at the turning-back position Tx takes a straight posture. The path planning unit 102 may generate a path such that the front frame 2a and the rear frame 2b take a bending posture at the turning-back position Tx.

[0135] In this way, a series of processing for generating a path of traveling of the wheel loader 1 is ended (“end” in FIG. 8).<Actions and Effects>

[0136] Although there is a description partially overlapping with the above description, the characteristic configurations and actions and effects of the present embodiment will be collectively described as follows.

[0137] As illustrated in FIGS. 5, 7, and 8, the position estimation unit 101 of the automation controller 100 recognizes the loading target 300 onto which material loaded on the work implement 3 is loaded on the basis of a detection result of the perception device 111. The path planning unit 102 of the automation controller 100 recognizes the loading position A1 in a case where the material is loaded onto the loading target 300. The path planning unit 102 calculates the minimum distance x1 by which the excavation position at which the wheel loader 1 excavates the excavation target 200 when the wheel loader 1 executes the excavation and loading work is to be separated from the loading position A1 by the dimension of the wheel loader 1.

[0138] The path of traveling in a case where the excavation and loading work is automatically controlled can be appropriately set by the shortest path on which traveling can be performed without stationary steering by the turning ability of the wheel loader 1 being determined from the dimension of the wheel loader 1. The shortest path on which the wheel loader 1 can perform V-shape traveling can be set, and the excavation and loading work can be efficiently executed.

[0139] As illustrated in FIGS. 1 and 7, the dimension of the wheel loader 1 may include the dimension in the front-rear direction of the wheel loader 1. The distance x1 can be calculated from the length L1 or the like that is the total length of the wheel loader 1 in the front-rear direction, and the path of traveling in a case where the excavation and loading work is automatically controlled can be appropriately set.

[0140] As illustrated in FIG. 7, the travel path when after the wheel loader 1 excavates the excavation target 200, the wheel loader 1 performs loaded backing may be separated from the loading position A1 by a distance greatly larger than the distance x1. By the path of traveling of the wheel loader 1 being set at a position separated from the loading position A1 by a distance greatly larger than the distance x1, the wheel loader 1 can be caused to travel without stationary steering.

[0141] As illustrated in FIG. 7, the path planning unit 102 may recognize the shape of the excavation target 200 on the basis of a detection result of the perception device 111 and select the excavation position Bx on the basis of the shape of the excavation target 200. An area where the wheel loader 1 can excavate the excavation target 200 is calculated according to the distance x1, and where to set the excavation position Bx in the excavatable area can be selected from the shape of the excavation target 200.

[0142] Since the path of traveling of the wheel loader 1 can be appropriately set, the excavation and loading work can be efficiently executed.

[0143] As illustrated in FIG. 7, the path planning unit 102 can select, as the excavation position Bx, a position that can minimize a travel distance by which the wheel loader 1 that excavates the excavation target 200 advances toward the excavation target 200 so as to load a certain amount of the material onto the work implement 3.

[0144] By the path of traveling in a case where the wheel loader 1 performs the excavation work being set to the shortest path, the excavation work can be efficiently performed.

[0145] As illustrated in FIG. 7, the path planning unit 102 may determine the turning-back position Tx at which the wheel loader 1 is switched from loaded backing to loaded advancing by the dimension of the wheel loader 1. The path planning unit 102 can determine a position separated from the excavation target 200 by the length L1 using the excavation position Bx as a starting point as the turning-back position Tx, and can appropriately set a path of traveling in a case where the excavation and loading work is automatically controlled.

[0146] As illustrated in FIGS. 1 and 2, the main body of the wheel loader 1 may include the front frame 2a and the rear frame 2b bendable with respect to the front frame 2a. The wheel loader 1 includes an articulated structure in which the front frame 2a and the rear frame 2b are bendable from each other, so that the turning radius in the case of turning traveling can be reduced. The path of traveling can be shortened in a case where the wheel loader 1 performs the excavation and loading work.

[0147] As illustrated in FIG. 7, the wheel loader 1 may take a straight posture in which the front frame 2a and the rear frame 2b are not bent from each other in a case where the excavation target 200 is excavated and in a case where the material loaded on the work implement 3 is loaded onto the loading target 300. By the wheel loader 1 taking a straight posture in a case where the excavation target 200 is excavated, the traction force of the vehicle can be sufficiently transmitted to the bucket 6 at the distal end of the work implement 3. By the wheel loader 1 taking a straight posture in a case where the material is loaded onto the loading target 300, the vehicle can be stabilized.

[0148] As illustrated in FIGS. 7 and 8, the path planning unit 102 may generate a travel path of the travel device 4 that can travel without stationary steering. Since a travel path on which the wheel loader 1 turns without stationary steering in which steering is performed while the wheel loader 1 is stopped is generated, local wear of the front wheel 4a can be reduced, and durability of the front wheel 4a can be improved.

[0149] In the above embodiment, the position estimation unit 101 of the automation controller 100 recognizes the position of the loading target 300 on the basis of a detection result of the perception device 111. The present disclosure is not limited thereto, and information of the self-position of the loading target 300 may be input from the loading target 300 to the automation controller 100 by inter-vehicle communication between the automation controller 100 and the loading target 300 via the communication device 150. The position estimation unit 101 can recognize the relative position of the loading target 300 with respect to the wheel loader 1 from information of the current position of the wheel loader 1 acquired by the position information acquisition device 112 and information of the self-position of the loading target 300. The position estimation unit 101 can recognize the relative position of the loading target 300 with respect to the excavation target 200 from the information of the excavation target 200 acquired by the perception device 111 and the relative position of the loading target 300 with respect to the wheel loader 1.

[0150] The automation controller 100 that forms the automatic control system of the wheel loader 1 described in the above embodiment is not necessarily mounted on the wheel loader 1. A controller outside the wheel loader 1 may construct a system included in the automation controller 100. A controller mounted on the wheel loader 1 may perform processing of transmitting information acquired by the external information acquisition unit 110, the vehicle information acquisition unit 120, and the like to an external controller, and the external controller that has received a signal may generate a travel path of the wheel loader 1.

[0151] The external controller may be disposed at a work site of the wheel loader 1, or may be disposed at a remote place away from the work site of the wheel loader 1.

[0152] The external controller may be a portable device. The external controller may be a portable device that can be carried and used by a worker, such as a notebook computer, a tablet computer, or a smartphone.

[0153] In the embodiment, the dump truck is exemplified as the loading target 300, and the work of loading material loaded on the work implement 3 (bucket 6) onto the vessel 301 has been described. The loading target 300 for loading material in the bucket 6 is not limited to the vessel 301 of the dump truck, and may be, for example, a hopper.

[0154] In the embodiment, an example has been described in which the excavation target 200 and the loading target 300 are detected by the perception device 111 mounted on the wheel loader 1. An object sensor that detects an object around the main body of the wheel loader 1 (work machine main body) is not necessarily mounted on the wheel loader 1. The object sensor may be disposed outside the work machine. For example, the object sensor may be disposed at a predetermined point of the work site, may be mounted on another work machine, or may be mounted on an unmanned aerial vehicle such as a drone.

[0155] In the embodiment, an example has been described in which the wheel loader 1 includes the cab 5 and is a manned vehicle in which the operator boards the cab 5.

[0156] The wheel loader 1 may be an unmanned vehicle. The wheel loader 1 may not include the cab 5 for the operator to board and operate. The wheel loader 1 may not include a steering function by a boarded operator. The wheel loader 1 may be a work machine dedicated to remote control. The operation of the wheel loader 1 may be performed by a wireless signal from a remote control device.<Supplementary Note>

[0157] The above description includes the following features.(Supplement 1)

[0158] A system including a work machine, including:

[0159] a work machine main body including a travel body;

[0160] a work implement attached to the work machine main body;

[0161] a sensor that detects an object around the work machine main body; and

[0162] a controller that generates a travel path of the travel body, in which

[0163] the object includes an excavation target that is a heap of material excavated by the work implement and a loading target onto which the material is loaded,

[0164] the travel path includes an excavation position at which the work machine excavates the excavation target and a loading position in a case where the material is loaded onto the loading target, and

[0165] the controller recognizes the loading target on a basis of a detection result of the sensor, recognizes the loading position, and calculates a minimum distance by which the excavation position is to be separated from the loading position by a dimension of the work machine.(Supplement 2)

[0166] The system according to Supplement 1, in which a dimension of the work machine includes a dimension in a front-rear direction of the work machine.(Supplement 3)

[0167] The system according to Supplement 1 or 2, in which the travel path in a case where the work machine performs loaded backing is separated from the loading position by a distance larger than the minimum distance.(Supplement 4)

[0168] The system according to Supplement 3, in which the controller recognizes a shape of the excavation target on a basis of a detection result of the sensor, and selects the excavation position on a basis of a shape of the excavation target.(Supplement 5)

[0169] The system according to Supplement 4, in which the controller selects, as the excavation position, a position that can minimize a travel distance by which the work machine that excavates the excavation target advances toward the excavation target so as to load a certain amount of the material onto the work implement.(Supplement 6)

[0170] The system according to any one of Supplements 1 to 5, in which the controller determines a turning-back position at which the work machine is switched from loaded backing to loaded advancing by a dimension of the work machine.(Supplement 7)

[0171] The system according to any one of Supplements 1 to 6, in which the work machine main body includes a front frame and a rear frame bendable with respect to the front frame.(Supplement 8)

[0172] The system according to Supplement 7, in which the work machine takes a straight posture in which the front frame and the rear frame are not bent from each other in a case where the excavation target is excavated and in a case where the material is loaded onto the loading target.(Supplement 9)

[0173] The system according to any one of Supplements 1 to 8, in which the controller generates the travel path of the travel body that can travel without stationary steering.(Supplement 10)

[0174] The system according to any one of Supplements 1 to 9, in which the work machine is capable of executing excavation and loading work in which after the work machine excavates the excavation target, the work machine performs loaded backing, and the work machine switches advancing and backing to perform loaded advancing toward the loading target, and

[0175] the controller calculates the minimum distance in a case where the excavation and loading work is executed.

[0176] It should be understood that the embodiments disclosed herein are illustrative in all respects and not restrictive. The scope of the present invention is defined not by the above description but by the claims, and is intended to include meanings equivalent to the claims and all modifications within the scope.REFERENCE SIGNS LIST1 Wheel loader

[0178] 2 Vehicle body frame

[0179] 2a Front frame

[0180] 2b Rear frame

[0181] 3 Work implement

[0182] 4 Travel device

[0183] 4a Front wheel

[0184] 4b Rear wheel

[0185] 6 Bucket

[0186] 6a Blade edge

[0187] 6aC Center point

[0188] 6c Width direction center

[0189] 14 Boom

[0190] 50 Vehicle body controller

[0191] 60 Engine controller

[0192] 70 Transmission controller

[0193] 80 Work implement controller

[0194] 100 Automation controller

[0195] 101 Position estimation unit

[0196] 102 Path planning unit

[0197] 103 Path follow-up control unit

[0198] 110 External information acquisition unit

[0199] 111 Perception device

[0200] 120 Vehicle information acquisition unit

[0201] 150 Communication device

[0202] 200 Excavation target

[0203] 201 Top portion

[0204] 202 Skirt

[0205] 203 Low heap area

[0206] 204 Accumulation area

[0207] 300 Loading target

[0208] 301 Vessel

[0209] 306 Rear upper edge

[0210] A1 Loading position

[0211] B1 Temporary excavation position

[0212] Bx Excavation position

[0213] P Path

[0214] T1 Temporary turning-back position

[0215] Tx Turning-back position

[0216] x1 Distance.

Examples

Embodiment Construction

[0019]Hereinafter, an embodiment will be described with reference to the drawings. In the following description, the same parts and components are denoted by the same reference signs. This also applies to their names and functions. Therefore, detailed descriptions thereof will not be repeated. It is also originally planned that any configurations are extracted from the embodiment and are freely combined.

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[0020]In the embodiment, a wheel loader 1 will be described as an example of a work machine. FIG. 1 is a side view of the wheel loader 1 as an example of a work machine. FIG. 2 is a plan view of the wheel loader 1 illustrated in FIG. 1.

[0021]As illustrated in FIGS. 1 and 2, the wheel loader 1 mainly includes a vehicle body frame 2, a work implement 3, a travel device 4, and a cab 5. The vehicle body frame 2, the cab 5, and the like form the vehicle body of the wheel loader 1. The work implement 3 and the travel device 4 are attached to the vehicle body of the wheel loader 1. The ma...

Claims

1. A system comprising a work machine, comprising:a work machine main body including a travel body;a work implement attached to the work machine main body;a sensor that detects an object around the work machine main body; anda controller that generates a travel path of the travel body, whereinthe object includes an excavation target that is a heap of material excavated by the work implement and a loading target onto which the material is loaded,the travel path includes an excavation position at which the work machine excavates the excavation target and a loading position in a case where the material is loaded onto the loading target, andthe controller recognizes the loading target on a basis of a detection result of the sensor, recognizes the loading position, and calculates a minimum distance by which the excavation position is to be separated from the loading position by a dimension of the work machine.

2. The system according to claim 1, wherein a dimension of the work machine includes a dimension in a front-rear direction of the work machine.

3. The system according to claim 1, wherein the travel path in a case where the work machine performs loaded backing is separated from the loading position by a distance larger than the minimum distance.

4. The system according to claim 3, wherein the controller recognizes a shape of the excavation target on a basis of a detection result of the sensor, and selects the excavation position on a basis of a shape of the excavation target.

5. The system according to claim 4, wherein the controller selects, as the excavation position, a position that can minimize a travel distance by which the work machine that excavates the excavation target advances toward the excavation target so as to load a certain amount of the material onto the work implement.

6. The system according to claim 1, wherein the controller determines a turning-back position at which the work machine is switched from loaded backing to loaded advancing by a dimension of the work machine.

7. The system according to claim 1, wherein the work machine main body includes a front frame and a rear frame bendable with respect to the front frame.

8. The system according to claim 7, wherein the work machine takes a straight posture in which the front frame and the rear frame are not bent from each other in a case where the excavation target is excavated and in a case where the material is loaded onto the loading target.

9. The system according to claim 1, wherein the controller generates the travel path of the travel body that can travel without stationary steering.

10. The system according to claim 1, wherein the work machine is capable of executing excavation and loading work in which after the work machine excavates the excavation target, the work machine performs loaded backing, and the work machine switches advancing and backing to perform loaded advancing toward the loading target, andthe controller calculates the minimum distance in a case where the excavation and loading work is executed.

11. A controller for a work machine of a work machine including a travel body and a work implement, the controller generating a travel path of the travel body, whereinthe travel path includes an excavation position at which the work machine excavates an excavation target that is a heap of material excavated by the work implement and a loading position in a case where the material is loaded onto a loading target onto which the material is loaded, andthe controller recognizes the loading target on a basis of a detection result of a sensor that detects an object around a work machine main body,recognizes the loading position, andcalculates a minimum distance by which the excavation position is to be separated from the loading position by a dimension of the work machine.

12. A path generation method for a work machine of a work machine including a travel body and a work implement, the path generation method being for generating a travel path of the travel body, whereinthe travel path includes an excavation position at which the work machine excavates an excavation target that is a heap of material excavated by the work implement and a loading position in a case where the material is loaded onto a loading target onto which the material is loaded, andthe path generation method comprising:recognizing the loading target on a basis of a detection result of a sensor that detects an object around a work machine main body;recognizing the loading position; andcalculating a minimum distance by which the excavation position is to be separated from the loading position by a dimension of the work machine.

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