Working machinery

Abstract

To provide a work machine that allows for the selection of the optimal excavation location for efficient excavation work, we offer a machine that can perform excavation work. [Solution] The present invention provides a work machine comprising: a work tool attached to the tip of a work device for excavating an object to be excavated; and an excavation position setting unit that sets the excavation position of the object to be excavated by the work tool based on information about the object to be excavated, wherein the excavation position setting unit corrects the height information of the object to be excavated based on information such as structures arranged around the object to be excavated, and sets the excavation position based on the corrected height information of the object to be excavated.

Description

Technical Field

[0001] The present invention relates to a working machine.

Background Art

[0002] Conventionally, there has been proposed a working machine (also referred to as a working vehicle) such as a wheel loader that can efficiently excavate an object to be excavated such as earth and sand by a working tool such as a bucket attached to the tip of a working device.

[0003] For example, Patent Document 1 describes a working vehicle (described as a front end loader) equipped with a working tool including a bucket, which includes a step of determining at least one excavation start candidate area, and a step of evaluating at least one performance criterion to determine the quality level of the result obtained using at least one candidate position, and a step of selecting a start position according to the quality level of the excavation result obtained using the proposed start position. A working vehicle that selects an optimal excavation start position in a grading operation using a topographic map of an excavation area is described.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, in the working vehicle described in Patent Document 1, there is a possibility that the object to be excavated cannot necessarily be excavated efficiently.

[0006] For example, in the working vehicle described in Patent Document 1, in order to select an optimal excavation start position from a plurality of excavation start candidate positions, it is necessary to evaluate and compare performance criteria for all excavation start candidate positions, and it is considered that a large computational load and calculation time are required for selecting the optimal excavation start position.

[0007] Furthermore, in the work vehicle described in Patent Document 1, the material to be excavated is the sediment present in a flat work area. Therefore, if a structure surrounds the material to be excavated, such as a wall surrounding a stockyard (a place where the material to be excavated is piled up and stored), it is considered that it is not possible to select the optimal starting position for excavation near the structure.

[0008] This invention has been made in view of the above problems, and its purpose is to provide a work machine that can select the optimal excavation position in order to perform excavation work efficiently. [Means for solving the problem]

[0009] To achieve the above objective, the present invention provides a work machine comprising: a work tool attached to the tip of a work device for excavating an object to be excavated; and an excavation position setting unit that sets the excavation position of the object to be excavated by the work tool based on information about the object to be excavated, wherein the excavation position setting unit corrects the height information of the object to be excavated based on at least one piece of information from information about structures arranged around the object to be excavated and information about the excavation area in which the object to be excavated is located, and sets the excavation position based on the corrected height information of the object to be excavated. [Effects of the Invention]

[0010] According to the present invention, the excavation position of the excavation target by the work tool is set based on height information of the excavation target corrected based on information such as structures placed on site, so the optimal excavation position can be selected without requiring a large computational load or calculation time.

[0011] Other issues, configurations, and effects not mentioned above will be clarified by the following description of the embodiments. [Brief explanation of the drawing]

[0012] [Figure 1] A schematic diagram showing the external appearance of a work machine according to the first embodiment of the present invention. [Figure 2]A diagram showing a control system for a work machine according to a first embodiment of the present invention. [Figure 3] A functional block diagram of an automatic driving control device according to the first embodiment of the present invention. [Figure 4] An example of an area map showing a work area according to the first embodiment of the present invention. [Figure 5] A functional block diagram of the excavation position determination performed by the action decision unit 110 according to the first embodiment of the present invention. [Figure 6] A flowchart showing an example of drilling position determination performed by the action decision unit 110 according to the first embodiment of the present invention. [Figure 7] A figure showing an example of vertex extraction performed by the action decision unit 110 according to the first embodiment of the present invention. [Figure 8] This figure shows another example of vertex extraction performed by the action decision unit 110 according to the first embodiment of the present invention. [Figure 9] An example of a filter used in another example of vertex extraction performed by the action decision unit 110 according to the first embodiment of the present invention. [Figure 10] A diagram showing an example for comparison with the excavation position determination according to the first embodiment of the present invention. [Figure 11] A diagram showing an example of the effect of determining the excavation location according to the first embodiment of the present invention. [Figure 12] A functional block diagram of the excavation position determination performed by the action determination unit 110 according to a second embodiment of the present invention. [Figure 13] A flowchart showing an example of excavation position determination performed by the action decision unit 110 according to a second embodiment of the present invention. [Figure 14] A diagram showing an example of the estimation of excavation volume performed by the action decision unit 110 according to the second embodiment of the present invention. [Figure 15] A functional block diagram of the excavation position determination performed by the action decision unit 110 according to the third embodiment of the present invention. [Figure 16] A flowchart showing an example of drilling position determination performed by the action decision unit 110 according to the third embodiment of the present invention. [Figure 17] A flowchart showing an example of excavation position determination performed by the action decision unit 110 according to the fourth embodiment of the present invention. [Figure 18] FIG. showing an example of priority filter generation performed by the action determination unit 110 according to the fourth embodiment of the present invention. [Figure 19] FIG. showing an example of grid map correction and vertex extraction performed by the action determination unit 110 according to the fourth embodiment of the present invention. [Figure 20] FIG. showing an example of priority filter generation performed by the action determination unit 110 according to the fifth embodiment of the present invention. [Figure 21] FIG. showing an example of grid map correction and vertex extraction performed by the action determination unit 110 according to the fifth embodiment of the present invention. [Figure 22] An example of an area map showing the work area according to the sixth embodiment of the present invention. [Figure 23] FIG. showing an example of priority filter generation for area A2 performed by the action determination unit 110 according to the sixth embodiment of the present invention. [Figure 24] FIG. showing an example of priority filter generation for area A3 performed by the action determination unit 110 according to the sixth embodiment of the present invention. [Figure 25] FIG. showing an example of grid map correction and vertex extraction for area A2 performed by the action determination unit 110 according to the sixth embodiment of the present invention. [Figure 26] FIG. showing an example of grid map correction and vertex extraction for area A3 performed by the action determination unit 110 according to the sixth embodiment of the present invention.

BEST MODE FOR CARRYING OUT THE INVENTION

[0013] Hereinafter, a wheel loader will be taken as an example of a working machine according to an embodiment of the present invention, and it will be described with reference to the drawings. In each figure, the same members are denoted by the same reference numerals, and duplicate explanations will be omitted as appropriate.

[0014] [First Embodiment] The first embodiment of the present invention will be described with reference to FIGS. 1 to 11.

[0015] [Configuration] Figure 1 is a schematic diagram showing the external appearance of a work machine according to the first embodiment of the present invention, and Figure 2 is a diagram showing the control system of the work machine according to the first embodiment of the present invention. In this embodiment, a wheel loader will be used as an example of the work machine.

[0016] In Figure 1, the wheel loader V1 includes a bucket 1, which is a work tool, at the front of the vehicle body; a bucket cylinder 13 that drives the bucket 1; a lift arm 6 that rotatably supports the bucket 1; a lift cylinder 18 that drives the lift arm 6; a front frame 9F that rotatably supports the lift arm 6; and a rear frame 9R that bends the front frame 9F around an axis in the vertical direction of the vehicle body. It also includes a bell crank 7 that rotatably supports the lift arm 6, and a bucket link 8 that connects the bucket 1 and the bell crank 7. In this embodiment, the bucket 1, lift arm 6, bell crank 7, bucket link 8, bucket cylinder 13, and lift cylinder 18 are collectively referred to as the work device as appropriate.

[0017] The work apparatus is configured such that the bucket 1 moves up and down as the lift arm 6 rotates due to the extension and retraction of the lift cylinder 18, and the bucket 1 also rotates relative to the lift arm 6 via the bucket link 8 as the bell crank 7 rotates relative to the lift arm 6 as the bucket cylinder 13 extends and retracts.

[0018] Furthermore, the wheel loader V1 is equipped with a front right tire 5FR and a front left tire 5FL on the front frame 9F, and a rear right tire 5RR (see Figure 2) and a rear left tire 5RL on the rear frame 9R. It moves by driving these tires and is also equipped with an articulated steering mechanism, which allows it to turn by bending the front frame 9F and the rear frame 9R.

[0019] In this embodiment, the bucket 1 is appropriately referred to as the work tool, the lift arm 6 as the front arm, and the front frame 9F, rear frame 9R, front right tire 5FR, front left tire 5FL, rear right tire 5RR, and rear left tire 5RL as the driving body.

[0020] In Figure 2, the control system is equipped with an engine 10 as a power source, and the engine 10 drives the hydraulic pump 11 and the transmission 20.

[0021] The transmission 20 transmits the driving force of the engine 10 to the front right tire 5FR and front left tire 5FL, and the rear right tire 5RR and rear left tire 5RL, respectively, via the axle 21 and the front differential 22F and rear differential 22R, thereby accelerating the wheel loader V1. The axle 21 is divided into front and rear halves around the center joint 24, which is a constant velocity joint, so that the driving force can be transmitted to the front differential 22F and rear differential 22R even when the vehicle body is bent.

[0022] On the other hand, the hydraulic pump 11, driven by the engine 10, supplies hydraulic fluid to the control valve 12. The hydraulic fluid is then distributed by the control valve 12 to drive the hydraulic actuators: the bucket cylinder 13, lift cylinder 18, steer cylinder 19, and brakes 23FR, 23FL, 23RR, and 23RL (see Figure 1 for details on the bucket cylinder 13, lift cylinder 18, and steer cylinder 19). As the bucket cylinder 13 and lift cylinder 18 extend and retract in response to the supply of hydraulic fluid, the angle of the bucket 1 relative to the lift arm 6 and the angle of the lift arm 6 relative to the front frame 9F change, respectively. Also, as the steer cylinder 19 extends and retracts in response to the supply of hydraulic fluid, the angle between the front frame 9F and the rear frame 9R changes. Furthermore, as the brakes 23FR, 23FL, 23RR, and 23RL operate in response to the supply of hydraulic fluid, the rotation of the tires 5FR, 5FL, 5RR, and 5RL is suppressed, causing the wheel loader V1 to slow down and stop.

[0023] The control system also includes an automatic driving control device 100, an engine control device 500, an actuator control device 600, positioning devices 51a and 51b, attitude sensors 52a and 52e, a communication interface 60, and an object detection sensor 71 (see Figure 1 for details on the positioning devices 51a and 51b, attitude sensors 52a and 52e, and object detection sensor 71).

[0024] In this embodiment, the positioning devices 51a and 51b measure the position of the wheel loader V1 in a local coordinate system or a global coordinate system at the site where the wheel loader V1 is operating, and are composed of a known GNSS (Global Navigation Satellite System). However, the present invention is not limited thereto, and the positioning devices 51a and 51b may be configured using a known SLAM (Simultaneous Localization and Mapping) with a camera or LiDAR.

[0025] Furthermore, the attitude sensors 52a and 52e measure the attitude of the bucket 1 and lift arm 6 with respect to the horizontal plane (reference plane), respectively, and are composed of known angle sensors such as potentiometers, but the present invention is not limited to this, and the attitude sensors 52a and 52e may be composed of encoders or IMUs (Inertial Measurement Units), or a combination of these may be used.

[0026] Furthermore, the object detection sensor 71 acquires information about the object to be excavated, and is composed of, for example, a known LiDAR, but the present invention is not limited to this, and any device that can acquire the shape of the object to be excavated, such as a stereo camera or radar, is acceptable, and it does not necessarily have to be mounted on a vehicle.

[0027] Furthermore, the communication interface 60 can be any device capable of acquiring the communication information described later from the process management terminal 800, such as a wireless communication device. The process management terminal 800 is a terminal for transmitting communication information to each machine on site, and may be a system in which the site manager manually creates and transmits the communication information, or it may be a system that acquires the progress of work throughout the site using sensors, etc., and automatically generates and transmits the communication information.

[0028] The automatic driving control device 100 generates engine control signals and actuator control signals in response to communication information from the process management terminal 800 via the communication interface 60, vehicle position information from positioning devices 51a and 51b, attitude information from attitude sensors 52a and 52e (work tool attitude information, front arm attitude information), and object detection information from object detection sensor 71, and transmits them to the engine control device 500 and actuator control device 600, respectively. In response to these signals, the engine control device 500 controls the rotational speed of the engine 10, and the actuator control device 600 controls the degree of opening and closing of the control valve 12.

[0029] Figure 3 is a functional block diagram of the automatic driving control device 100 according to the first embodiment of the present invention, and Figure 4 is an example of an area map showing the work area according to the first embodiment of the present invention.

[0030] In Figure 3, the automatic driving control device 100 includes an action decision unit 110, an action planning unit 120, an action control unit 130, and an area map holding unit 140.

[0031] The area map holding unit 140 receives and holds the area map of the work area as communication information from the process management terminal 800 via the communication interface 60, and also transmits the area map to the action decision unit 110 and the operation planning unit 120.

[0032] Here, the area map showing the work area is given as a region enclosed by multiple coordinate points, as shown in Figure 4, for example. In the figure, Q is the excavation target (e.g., gravel or other excavated material), and R is the loading target (e.g., a hopper for loading gravel, etc., into the processing plant). Region A, enclosed by P11, P12, P13, and P14 around Q, is the excavation area. Region B, enclosed by P51, P52, P53, and P54 around R, is the loading area. Region C, enclosed by P1, P2, P3, and P4, is the driving area. The areas indicated by diagonal lines are structures such as outer walls that surround the excavation area and loading area.

[0033] In the work area shown in Figure 4, the wheel loader V1 repeatedly performs the following operations: excavating the excavation target Q in area A, traveling through area C to move to area B, loading the excavated Q onto the loading target R in area B, and then traveling through area C again to return to area A. Since the travel path of the wheel loader V1 to perform the work in the shortest possible time is generally uniquely determined, in the absence of obstacles, the wheel loader V1 will travel along almost the same travel path (on the dashed line W in the figure) each time it performs work, excluding the excavation area. In this embodiment, the wheel loader V1 performs the work automatically, but even in the operation of a manually operated wheel loader, it often travels along almost the same travel path.

[0034] On the other hand, in the drilling area, it is necessary to change the drilling location to obtain a sufficient amount of drilling volume according to the distribution of the target Q to be drilled.

[0035] The action decision unit 110 receives communication information from the process management terminal 800 via the communication interface 60, an area map from the area map holding unit 140, vehicle position information from positioning devices 51a and 51b, posture information (work tool posture information, front arm posture information) from posture sensors 52a and 52e, and object detection information from object detection sensor 71, calculates the operating mode and target state of the wheel loader V1, and transmits it to the action planning unit 120.

[0036] Here, the operation mode refers to the mode that describes the manner of operation performed by the wheel loader V1, and includes automatic driving mode, automatic excavation mode, automatic lift mode, automatic soil discharge mode, and stop mode. The target state refers to the target position of the wheel loader V1 relative to the area map, the target position of the tip of the lift arm 6 relative to the front frame 9F, the target angle of the bucket 1 relative to the horizontal plane, the target excavation amount, and the target soil discharge amount.

[0037] The details of the excavation location determination performed by the action decision unit 110 will be described later.

[0038] The motion planning unit 120 receives the area map from the area map holding unit 140, the motion mode and target state from the action decision unit 110, vehicle position information from the positioning devices 51a and 51b, attitude information (work tool attitude information, front arm attitude information) from the attitude sensors 52a and 52e, and object detection information from the object detection sensor 71, calculates the control mode and target motion, and transmits it to the motion control unit 130.

[0039] Here, the control mode is calculated for each controlled object: the vehicle, the front arm, and the work tool. For example, if the operation mode is automatic driving mode, the vehicle is set to trajectory control mode so that it follows the target driving trajectory, and the front arm and work tool are set to speed control mode so that they maintain the driving posture. If the operation mode is automatic excavation mode, the vehicle is set to force control mode to control the driving force, and the front arm and work tool are set to trajectory control mode so that they follow the target claw trajectory.

[0040] Furthermore, the target motion is calculated for each controlled object—the vehicle, front arm, and work tool—according to the control mode and target state. Specifically, as a motion plan to match the vehicle, front arm, and work tool to the target state, the target trajectory is calculated when the control mode is trajectory control mode, the target speed is calculated when the control mode is speed control mode, and the target driving force is calculated when the control mode is force control mode. Note that the target motion may be calculated for each control cycle, or each time a target state is given. In addition, the target trajectory may be calculated using known algorithms such as clothoid curves or Bézier curves, and the target speed and target driving force may be calculated using known feedback control such as proportional control based on the difference between the current value and the target state and target trajectory.

[0041] Furthermore, if the operating mode is automatic drilling mode, drilling methods described in known literature (for example, Japanese Patent Publication No. 2022-112062) may be applied. Specifically, the traveling body may be set to a force control mode to control the driving force, the work tool may be driven into the object to be drilled in a posture substantially parallel to the ground, and the front arm and work tool may be set to a speed control mode, with the target speed being calculated sequentially so that the front arm and work tool rotate in accordance with the acceleration and deceleration of the travel. In addition, pressure sensors may be added to acquire the pressure of the bucket cylinder 13 and the lift cylinder 18, and drilling methods described in known literature (for example, International Publication No. 2023-182320) may be applied. In any case, the traveling body only needs to continue to output driving force during drilling, and the force control mode may be replaced with a position control mode, and the drilling position calculated by the drilling position determination may be used as the target position.

[0042] Furthermore, the motion planning unit 120 calculates target movements based on the area map and object detection information to ensure that the wheel loader V1 does not deviate from the work area and avoids contact with objects outside of area A, which is the excavation area.

[0043] The motion control unit 130 receives control mode, target motion, vehicle position information from positioning devices 51a and 51b, attitude information (work tool attitude information, front arm attitude information) from attitude sensors 52a and 52e, and object detection information from object detection sensor 71 from the motion planning unit 120. It generates control signals for the wheel loader V1's driving body, front arm, and work tool in accordance with the target motion and transmits them to the actuator control device 600 as driving control signal, front arm control signal, and work tool control signal, respectively.

[0044] For example, similar to conventional manual operation, the driving control signal may be the amount of pedal operation, and the front arm control signal and work tool control signal may be the amount of lever operation. In addition, each operation amount may be calculated using a pre-prepared map for the target speed and target driving force, or it may be calculated using known feedback control such as proportional control based on the difference in current values.

[0045] Furthermore, the operation control unit 130 calculates the required engine speed from each control signal and transmits it to the engine control device 500 as an engine control signal.

[0046] For example, it is a good idea to calculate how to increase the engine speed in proportion to the target speed, target driving force, or input variable.

[0047] Furthermore, based on the object detection information, the motion control unit 130 may calculate an engine control signal to reduce the engine speed or a travel control signal to stop travel if there is an object in the direction of travel of the wheel loader V1 outside of the excavation area A.

[0048] <Detailed explanation of the excavation location determination performed by the action decision unit 110> Figure 5 is a functional block diagram of the excavation position determination performed by the action decision unit 110 in the first embodiment of the present invention.

[0049] The excavation position determination is performed by the excavation position setting unit 101, which determines or sets the excavation position of the object to be excavated by the bucket 1. In this embodiment, the action determination unit 110 has the excavation position setting unit 101, and the action determination unit 110 performs the excavation position determination. The action determination unit 110 also makes decisions other than the excavation position, but since these are not directly related to the present invention, their description and explanation are omitted. Furthermore, the excavation position determination (excavation position setting unit 101) may be performed by a unit other than the action determination unit 110.

[0050] In Figure 5, the excavation position determination (excavation position setting unit 101) includes a bucket dimension holding unit 111, a grid calculation unit 112, a vertex position extraction unit 113, and an excavation position selection unit 114.

[0051] The bucket dimension holding unit 111 holds dimension information including the width of the bucket 1 and transmits the dimension information of the bucket 1 to the grid calculation unit 112.

[0052] The grid calculation unit 112 receives object detection information from the object detection sensor 71, vehicle position information from the positioning devices 51a and 51b, an area map from the area map holding unit 140, and bucket dimension information from the bucket dimension holding unit 111. It then converts the point cloud of object detection information into a grid map and transmits it to the vertex position extraction unit 113.

[0053] The conversion of object detection information from a point cloud to a grid map involves first converting the object detection information to the same coordinate system as the area map based on the vehicle's position information, and then converting it to a grid map using a known averaging method.

[0054] The grid size (distance between grid cells) at this time is set to be less than or equal to the width of bucket 1, based on the dimensional information of bucket 1. In this embodiment, the average method was used as the method for converting to a grid map, but the nearest neighbor method or the TIN method may also be used.

[0055] The vertex position extraction unit 113 receives a grid map from the grid calculation unit 112 and an area map from the area map holding unit 140, extracts the vertices of the excavation target, and transmits them to the excavation position selection unit 114.

[0056] Here, the vertices of the excavation target are the local maximum points on the grid map, and there may be multiple such points on the grid map. Details on how to calculate the vertices of the excavation target will be described later.

[0057] The drilling location selection unit 114 receives the vertices of the object to be drilled from the vertex location extraction unit 113, selects the optimal vertex from the object to be drilled as the drilling location, and transmits it to the operation planning unit 120.

[0058] In this embodiment, the excavation position selection unit 114 selects the excavation position according to the height of the top of the object to be excavated.

[0059] Next, with reference to Figures 6 to 9, the calculation flow for determining the excavation location in this embodiment will be explained.

[0060] Figure 6 is a flowchart showing an example of excavation position determination performed by the action decision unit 110 according to the first embodiment of the present invention, Figure 7 is a diagram showing an example of vertex extraction performed by the action decision unit 110 according to the first embodiment of the present invention, Figure 8 is a diagram showing another example of vertex extraction performed by the action decision unit 110 according to the first embodiment of the present invention, and Figure 9 is an example of a filter used in another example of vertex extraction performed by the action decision unit 110 according to the first embodiment of the present invention.

[0061] In Figure 6, in step S1101, the object detection sensor 71 acquires a point cloud as object detection information, and the process proceeds to step S1102.

[0062] In step S1102, based on the vehicle position information, the object detection information is converted to the same coordinate system as the area map, converted to a grid map using a known averaging method, and the process proceeds to step S1103.

[0063] In step S1103, the grid map is corrected, and the process proceeds to step S1104, where the vertices of the excavation target are extracted from the corrected grid map.

[0064] Here, the correction of the grid map and the extraction of vertices of the excavation target will be explained using Figures 7, 8, and 9.

[0065] Figure 7(a) is an example of a grid map, where the numbers indicate the height of each grid. The dotted lines in the figure represent the outer walls of the excavation areas included in the area map. The outer walls of the excavation areas are structures located within the excavation area that surround the objects to be excavated. Note that the height of the grids containing the outer walls is not uniform because the heights of the objects to be excavated around the outer walls and the shapes around the outer walls are uneven, and these were averaged together with the height of the outer walls when converted to a grid map.

[0066] Next, Figure 7(b) shows the corrected grid map. In the example in Figure 7, based on information about the outer wall of the excavation area, which is a structure placed around the excavation target, the height of the grids that include the outer wall and the grids outside the outer wall are set to 0.

[0067] Furthermore, Figure 7(c) shows the result of extracting vertices from the grid map in Figure 7(b). The following equation [Equation 1] is used to extract vertices. That is, if the height f(i,j) of the grid in row i (horizontal direction in the grid map) and column j (vertical direction in the grid map) is higher than the height f(i+k, j+l) of any of the surrounding grids, the height of the grid in row i and column j is kept as is; otherwise, the height of the grid in row i and column j is set to 0. Note that k and l are parameters that indicate the range of grids to be compared, and in the example in Figure 7, both k and l are set to -1 to 1. [Mathematics 1] TIFF2026059214000002.tif13116

[0068] In this way, based on the grid map, the height of the grid including the outer wall of the excavation area, which is a structure placed around the excavation target, and the grid outside the outer wall, are corrected to 0. By then comparing the height with the surrounding grids, the vertices of the excavation target within the excavation area can be extracted.

[0069] Next, Figure 8 shows another example of vertex extraction, which differs from Figure 7 in that it includes Figure 8(b'), in which weighted smoothing is applied to the grid map correction.

[0070] Figures 8(a) and 8(b) are the same as Figures 7(a) and 7(b), respectively. Figure 8(b') shows the result of weighted smoothing applied to Figure 8(b). The following [equation 2] is used for weighted smoothing. That is, the height g(i,j) of a grid of row i and column j is obtained by multiplying the heights f(i+k, j+l) of the surrounding grids by a weight h(k,l) and adding them together. Note that m and n are parameters that indicate the range of grids to be added together, and in the example of Figure 8, both m and n are set to 1, and the weights shown in Figure 9 are applied. [Math 2] TIFF2026059214000003.tif18116

[0071] In this way, by extracting vertices after performing weighted smoothing, adjacent vertices can be grouped together and extracted as a single vertex, as shown in Figure 8(c). As a result, the number of vertices extracted from the same grid map is reduced compared to the case without weighted smoothing, allowing for faster determination of the excavation location, as described later.

[0072] Returning to the explanation of Figure 6, in step S1105, the vertices are sorted in order of height and the process proceeds to step S1106. By sorting the vertices in order of height in this way, it becomes possible to determine in later steps whether or not excavation is possible, starting from the highest vertices.

[0073] In step S1106, depending on whether there are any unset vertices at the excavation location, the process proceeds to step S1107 if there are any unset vertices; otherwise, since all vertices have been set at the excavation location, the process proceeds to step S1109 and the work is interrupted.

[0074] In step S1107, depending on whether the height of the vertex is greater than or equal to the threshold Hmin, if the height of the vertex is greater than or equal to the threshold Hmin, the process proceeds to step S1108 and the position of the vertex at that time is set as the excavation position; otherwise, the process returns to step S1106.

[0075] The threshold Hmin is set to be greater than or equal to the height of bucket 1 when it touches the ground. By confirming that the height of the top of the object to be excavated is greater than or equal to the threshold Hmin, a sufficient amount of excavation can be ensured.

[0076] <Explanation of the effect of determining the excavation location from the vertex position> The effect of determining the excavation location according to the first embodiment of the present invention will be explained with reference to Figures 10 and 11.

[0077] Figure 10 shows an example for comparison with the drilling position determination according to the first embodiment of the present invention, and Figure 11 shows an example of the effect of the drilling position determination according to the first embodiment of the present invention.

[0078] Figures 10(a) and (b) show the front view (top) and plan view (bottom) of the excavation target within the excavation area before and after multiple excavations, respectively. Here, the front view is a diagram showing the view from the direction in which the wheel loader V1 enters the excavation area. Also, the arrows in Figure 10(a) indicate the excavation position, and in Figure 10, an example is shown where the center of the excavation area is always used as the excavation position, as is the conventional method of determination.

[0079] In Figure 10, regardless of the distribution of the material to be excavated, excavation continues with the center of the excavation area as the excavation location. As shown in Figure 10(b), the material to be excavated is left behind in a bowl-shaped pattern, and a large amount of the material to be excavated remains near the outer wall of the excavation area, which is a structure.

[0080] On the other hand, Figure 11 shows an example of determining the excavation location using the excavation location determination method of this embodiment. In Figure 11(a), the distribution of the excavation target before excavation is the same as in Figure 10(a), but in the excavation location determination method of this embodiment, the tops of the excavation target are extracted and used as the excavation location, so the position of the arrows is different.

[0081] Thus, in this embodiment, the excavation location is changed according to the position of the top of the excavation target, i.e., its distribution, so as shown in Figure 11(b), excavation can be performed without leaving a large amount of the excavation target near the outer wall of the excavation area, which is a structure.

[0082] Furthermore, in the excavation position determination of this embodiment, the apex of the object to be excavated is extracted based on the position of the outer wall of the excavation area, which is a structure. This allows for excavation of the apex near the outer wall without contacting the outer wall. Moreover, by enabling excavation of the apex near the outer wall, the amount that can be excavated relative to the total amount of the object to be excavated can be increased.

[0083] [Second Example] A second embodiment of the present invention will be described with reference to Figures 12, 13, and 14. The same reference numerals are used for components identical to those in the first embodiment, and their descriptions are omitted.

[0084] Figure 12 is a functional block diagram of the excavation position determination performed by the action decision unit 110 according to the second embodiment of the present invention, Figure 13 is a flowchart showing an example of the excavation position determination performed by the action decision unit 110 according to the second embodiment of the present invention, and Figure 14 is a diagram showing an example of the estimation of the excavation volume performed by the action decision unit 110 according to the second embodiment of the present invention.

[0085] In this embodiment, compared to the functional block diagram shown in Figure 5, the excavation volume estimation unit 115 is added in Figure 12, and compared to the flowchart shown in Figure 6, steps S1111 and S1112 are added in Figure 13.

[0086] In Figure 12, the excavation volume estimation unit 115 receives dimensional information of bucket 1 from bucket dimension holding unit 111, a grid map from grid calculation unit 112, and vertex positions of the excavation target from vertex position extraction unit 113. It then estimates the volume of excavated material that can be scooped up by bucket 1 when excavation is performed at the position of each vertex of the excavation target (excavation volume) and transmits this to the excavation position selection unit 114.

[0087] Here, the volume of the excavated object (excavation volume) can be simply calculated by multiplying the average height of the grid contained within bucket 1 when the center of bucket 1 is aligned with the vertex of the excavated object (▲ in the figure), as shown in Figure 14(a), by the area of ​​bucket 1 when projected onto a horizontal plane. Alternatively, as shown in Figure 14(b), it can be calculated by multiplying the average height of the grid contained within the width of bucket 1 (horizontal direction in the figure), including the vertex of the excavated object, by the distance (vertical direction in the figure), and the width of bucket 1.

[0088] In Figure 13, if the height of the apex is greater than or equal to the threshold Hmin in step S1107, the excavation volume is estimated in step S1111, and the process proceeds to step S1112.

[0089] In Figure 13, in step S1112, depending on whether the estimated excavation volume is greater than or equal to the threshold Vmin, if the excavation volume is greater than or equal to the threshold Vmin, the process proceeds to step S1108 and the position of the peak at that time is set as the excavation position; otherwise, the process returns to step S1106.

[0090] The threshold Vmin should be set to be greater than or equal to the capacity of bucket 1. By confirming that the estimated excavation volume relative to the top of the object to be excavated is greater than or equal to the threshold Vmin, a sufficient amount of excavation can be more reliably secured.

[0091] [Third embodiment] A third embodiment of the present invention will be described with reference to Figures 15 and 16. Components identical to those in the first and second embodiments are denoted by the same reference numerals, and their descriptions are omitted.

[0092] Figure 15 is a functional block diagram of the excavation position determination performed by the action decision unit 110 according to the third embodiment of the present invention, and Figure 16 is a flowchart showing an example of the excavation position determination performed by the action decision unit 110 according to the third embodiment of the present invention.

[0093] In this embodiment, compared to the functional block diagrams shown in Figures 5 and 12, Figure 15 adds the excavation target replenishment request unit 116, and compared to the flowcharts shown in Figures 6 and 13, Figure 16 adds steps S1121 and S1122.

[0094] In Figure 15, the drilling target replenishment request unit 116 receives the vertex of the drilling target from the vertex position extraction unit 113 and the drilling interruption flag from the drilling position selection unit 114, and transmits a drilling target replenishment request to the process management terminal 800 via the communication interface 60, requesting the replenishment of drilling targets in the drilling area.

[0095] In Figure 16, after setting the excavation position in step S1108, in step S1121, depending on whether the maximum height of the top of the object to be excavated is greater than or equal to the threshold Hmin2, if the maximum height of the top is greater than or equal to the threshold Hmin2, the excavation position determination is terminated; otherwise, the process proceeds to step S1122.

[0096] On the other hand, if there are no unset vertices at the excavation location in step S1106 and the work is interrupted in step S1109, the process proceeds to step S1122, in which step S1122 sends the above-mentioned request to replenish the excavation target and terminates the excavation location determination.

[0097] By sending a request to replenish the excavation target in the event of a work interruption, the site manager can be reliably notified that the work has been interrupted due to a shortage of excavation target material. Furthermore, even if the work has not been interrupted, sending a request to replenish the excavation target material according to the height of the excavation target's peak allows the site manager to be notified in advance of the possibility of a shortage of excavation target material before the work is interrupted.

[0098] Furthermore, it is desirable to set the threshold Hmin2 to a value greater than the threshold Hmin in order to determine if there is a possibility of insufficient material to be excavated before work is interrupted.

[0099] [Fourth embodiment] A fourth embodiment of the present invention will be described with reference to Figures 17, 18, and 19. Components identical to those in the first to third embodiments are denoted by the same reference numerals, and their descriptions are omitted.

[0100] Figure 17 is a flowchart showing an example of excavation position determination performed by the action decision unit 110 according to the fourth embodiment of the present invention.

[0101] In this embodiment, compared to the flowchart shown in Figure 6, step S3102 is added in Figure 17, and step S1103 is changed to step S3103.

[0102] In Figure 17, after converting to a grid map in step S1102, a priority filter is generated based on the area map in step S3102, and the process proceeds to grid map correction in step S3103.

[0103] Figure 18 shows an example of priority filter generation performed by the action decision unit 110 according to the fourth embodiment of the present invention.

[0104] Figure 18(i) shows the information on the excavation areas included in the area map, with 1 representing areas where excavation is not possible and 0 representing areas where excavation is possible.

[0105] The priority filter is generated based on the information of the drilling area using the following formula [Equation 3] as shown in Figure 18(ii). [Math 3] TIFF2026059214000004.tif24124

[0106] According to the calculation in formula [Equation 3], if the value of any grid f(i,j) in the excavation area is 0, i.e., it is an area where excavation is possible, a value of 1 or more is set for the corresponding grid g(i,j) in the priority filter. If the value of any grid f(i,j) in the excavation area is 1, i.e., it is an area where excavation is not possible, a value of 0 is set for the corresponding grid g(i,j) in the priority filter. Furthermore, if the value of any grid f(i,j) in the excavation area is 0 and the surrounding grids are also 0, meaning there are no areas where excavation is not possible, then the value is 1. If any of the surrounding grids are 1, meaning there is an adjacent grid where excavation is not possible, then the value of the corresponding grid g(i,j) in the priority filter is the sum of the values ​​of the adjacent grids.

[0107] In this way, a priority filter is generated based on the boundary between the object to be excavated and non-excavated structures such as outer walls that surround the object to be excavated. This filter excludes non-excavated structures such as outer walls from the excavation location, while setting the priority for the excavation location so that the object to be excavated near the boundary has a higher priority.

[0108] In step S3103, a priority filter is used to correct the grid map of the excavation target.

[0109] Figure 19 shows an example of grid map correction and vertex extraction performed in step S3103.

[0110] Figure 19(a) is the grid map before correction. By multiplying the values ​​of each grid in the priority filter in Figure 18(ii) by the values ​​of each grid before correction, it is transformed into the grid map in Figure 19(b).

[0111] Next, vertices are extracted from the grid map in Figure 19(b) as shown in the grid map in Figure 19(c). Note that the above [Equation 1] is used for vertex extraction.

[0112] As described above, by generating a priority filter based on the excavation area information contained in the area map and correcting the grid map of excavation targets using the priority filter, the locations of excavation targets near the outer walls of the excavation area, which are structures, become easier to extract as vertices. As a result, it becomes possible to excavate targets near the outer walls, and the amount of excavable material relative to the total amount of excavation targets can be increased.

[0113] [Fifth Example] A fifth embodiment of the present invention will be described with reference to Figures 20 and 21. The same reference numerals are used for components identical to those in the first to fourth embodiments, and their descriptions are omitted.

[0114] Figure 20 shows an example of priority filter generation performed by the action decision unit 110 according to the fifth embodiment of the present invention (another example of the fourth embodiment).

[0115] Figure 20(i), like Figure 18(i), shows information about the excavation areas contained within the area map, but differs in that it represents the excavable areas not only as 0, but also as a decimal number corresponding to the distance from the back wall of the excavation area, specifically a decimal number that approaches 1 as the distance from the back wall of the excavation area decreases.

[0116] Furthermore, the priority filter is generated based on the information of the drilling area using the following formula [Equation 4] as shown in Figure 20(ii). [Math 4] TIFF2026059214000005.tif25143

[0117] According to the calculation in formula [Equation 4], if the value of any grid f(i,j) in the excavation area is less than 1, i.e., it is an area where excavation is possible, a value greater than 0 is set for the corresponding grid g(i,j) in the priority filter. If the value of any grid f(i,j) in the excavation area is 1, i.e., it is an area where excavation is impossible, then 0 is set for the corresponding grid g(i,j) in the priority filter. Furthermore, if the value of any grid f(i,j) in the excavation area is 0 and the surrounding grids are also 0, meaning there are no areas where excavation is impossible, then 1 is set. If any of the surrounding grids are greater than 0 or close to a grid where excavation is impossible (1), then the value of the arbitrary grid f(i,j) is subtracted from the value of the adjacent grid, and these values ​​are added together to determine the value of the corresponding grid g(i,j) in the priority filter.

[0118] In this way, a priority filter is generated according to the excavation direction. If there are structures surrounding the excavation target in the direction of excavation, such as the outer wall of the excavation area, that are not the excavation target, the priority near the boundary with these structures is lowered, and the priority of the area closer to the excavation direction is set higher than the priority of the area further away.

[0119] Figure 21 shows an example of grid map correction and vertex extraction performed in step S3103 (another example of the fourth embodiment).

[0120] Figure 21(a) is the grid map before correction. By multiplying the values ​​of each grid in the priority filter in Figure 20(ii) by the values ​​of each grid before correction, it is converted to the grid map in Figure 21(b).

[0121] Next, vertices are extracted from the grid map in Figure 21(b) as shown in the grid map in Figure 21(c). Note that the above [Equation 1] is used for vertex extraction.

[0122] As described above, by representing the excavation area information not only as 0, but also as a decimal value corresponding to the distance from the back wall of the excavation area, a priority filter is generated so that the value becomes smaller near the back wall of the excavation area. As a result, positions closer to the front of the excavation area are more likely to be extracted as vertices than those near the back wall of the excavation area, making it easier to avoid bucket 1 contacting the back wall of the excavation area in relation to the excavation direction during excavation.

[0123] [Sixth embodiment] A sixth embodiment of the present invention will be described with reference to Figures 22 to 26. Components identical to those in the first to fifth embodiments are denoted by the same reference numerals, and their descriptions are omitted.

[0124] Figure 22 is an example of an area map showing a work area according to the sixth embodiment of the present invention. In the area map of Figure 22, in addition to the area map shown in Figure 4, the excavation targets Q2, Q3a, and Q3b are added. The area A2 enclosed by P21, P22, P23, and P24 around Q2, and the area A3 enclosed by P31, P32, P33, and P34 around Q3a and Q3b are excavation areas. The excavation target Q2 is in contact with the wall only on the far side of the excavation area, and the excavation targets Q3a and Q3b are not in contact with the wall in any direction, but within the excavation area, the excavation targets Q3a and Q3b are located close to each other.

[0125] In these cases, for example, if only the central parts of the excavation targets Q2 and Q3a are excavated, the excavated material that is not scooped up by bucket 1 will be pushed sideways, causing the excavation targets Q2 and Q3a to spread out and potentially extend beyond the areas A2 and A3, respectively (see Figure 10). Also, the excavated material from excavation target Q3a may mix with the adjacent excavation target Q3b. Therefore, depending on the distribution of the excavation targets, it may be necessary to excavate the peripheral parts away from the center of the excavation targets. The present invention can also be applied in such cases.

[0126] Figures 23 and 24 show examples of priority filter generation for regions A2 and A3 respectively, performed by the action decision unit 110 according to the sixth embodiment of the present invention.

[0127] Figures 23(i) and 24(i) show the information of the excavation areas contained within the area map. Although there are no walls on the side of area A2, when excavating target Q2, a virtual wall is set at the boundary of the side of area A2 where target Q2 is excavated, as shown in Figure 23(i). Similarly, although there are no walls in area A3, when excavating target Q3a, as shown in Figure 24(i), the left side including target Q3a is treated as the excavation target, and the right side including target Q3b is treated as not being the excavation target, and a virtual wall is set at the boundary between them. Each priority filter is generated based on the information of the excavation area, using the formula [Equation 4], similar to Figure 20(ii), as shown in Figures 23(ii) and 24(ii).

[0128] Figures 25 and 26 show an example of extracting vertices by applying priority filters to regions A2 and A3, respectively, in the action decision unit 110 according to the sixth embodiment of the present invention.

[0129] Figures 25(a) and 26(a) show the grid maps before correction. By multiplying the values ​​of each grid in the priority filters in Figures 23(ii) and 24(ii) by the values ​​of each grid before correction, they are converted to the grid maps shown in Figures 25(b) and 26(b).

[0130] Next, vertices are extracted from the grid maps in Figures 25(b) and 26(b) as shown in the grid maps in Figures 25(c) and 26(c). Note that the above [Equation 1] is used for vertex extraction. In both Figures 25(c) and 26(c), the area surrounding the excavation target is extracted as the highest vertex (the grid with a value of 211 in Figure 25(c) and the grid with a value of 172 in Figure 26(c)).

[0131] As described above, the priority filter of this embodiment can be applied even when the wall surface exists only on the far side relative to the excavation direction in the excavation area, and the priority filter is generated so that the value increases near the boundary of the area. As a result, the same effect as when there are walls in three directions is obtained, and the surrounding parts of the excavation target are more easily extracted as vertices, in other words, they are more easily set as excavation locations, so that the excavation target does not extend outside the area.

[0132] Furthermore, the priority filter of this embodiment can also be applied when different (separate) excavation targets are adjacent to each other in the excavation area without being separated by a wall. In this case, the priority filter is generated so that the value is larger near the boundary of the side designated as the excavation target. As a result, the area around the excavation target designated as the excavation target, particularly near the boundary with other excavation targets, is more likely to be extracted as a vertex, or in other words, more likely to be set as an excavation location. This prevents the excavation target from extending outside the area or mixing with adjacent excavation targets.

[0133] [summary] As described above, the work machine (wheel loader V1) of this embodiment is a work machine that includes a work tool (bucket 1) attached to the tip of the work device for excavating an object to be excavated, and an excavation position setting unit 101 that sets the excavation position of the object to be excavated by the work tool based on information about the object to be excavated, wherein the excavation position setting unit 101 uses information about structures (such as the outer wall of the excavation area) arranged around the object to be excavated (in contact with or at a distance from it) (see Figures 7 and 8), and information about the excavation area (boundary) where the object to be excavated is located (see Figures 23 and 24), with a small portion of these being information. At the very least, the height information of the object to be excavated is corrected based on one piece of information (for example, information on the excavation area contained in the area map holding unit 140), or information on a separate object to be excavated (or its boundary) arranged around the object to be excavated (within the excavation area) (see Figures 23 and 24), and the excavation position is set based on the corrected height information of the object to be excavated (a grid map obtained by correcting a grid map converted from the point cloud of object detection information, for example, Figures 7(b) and 8(b) obtained by correcting Figures 7(a) and 8(a)) (Embodiments 1 to 6).

[0134] The excavation position setting unit 101 sets a priority (priority filter, e.g., Figures 18(ii), 20(ii), etc.) for setting the excavation position based on at least one piece of information from the information of the structure and the information of the excavation area (boundary), or the information of the boundary with the separate excavation target, and corrects the height information of the excavation target based on the priority (e.g., Figures 19(b), 21(b), etc.) (Fourth and fifth embodiments).

[0135] The excavation position setting unit 101 sets the priority (priority filter, for example, Figure 20(ii), etc.) based on the excavation direction of the object to be excavated by the work tool (Fifth Embodiment).

[0136] The excavation position setting unit 101 sets the priority (priority filter, for example, Figure 20(ii), etc.) such that the near side has a higher priority than the far side with respect to the excavation direction of the object to be excavated by the work tool (Fifth Embodiment).

[0137] The excavation position setting unit 101 extracts the vertices of the excavation target from height information of the excavation target (for example, Figures 7(b), 8(b), etc.) corrected based on at least one piece of information from the structure information and the excavation area (boundary thereof), or based on the information of the separate excavation target (boundary therewith) (for example, Figures 7(c), 8(c), etc.), and sets the excavation position based on the height of the extracted vertices (Embodiments 1 to 6).

[0138] The drilling position setting unit 101 determines whether drilling is possible in order from the highest vertex when multiple vertices have been extracted (Embodiments 1 to 6).

[0139] The excavation position setting unit 101 estimates the volume of the object to be excavated (excavation volume) that can be excavated around the apex (excavation volume estimation unit 115), and determines whether or not excavation is possible based on the estimated volume of the object to be excavated (excavation volume) (second embodiment).

[0140] The excavation position setting unit 101 sets the position of the apex to the excavation position if the estimated volume of the object to be excavated (excavation volume) is equal to or greater than a predetermined threshold (Vmin) (second embodiment).

[0141] The excavation position setting unit 101 determines whether or not to send an excavation target replenishment request requesting replenishment of the excavation target based on the presence or absence of the vertex or the height of the vertex (excavation target replenishment request unit 116) (third embodiment).

[0142] The excavation position setting unit 101 transmits a request to replenish the excavation target if the maximum value of the height of the apex is less than a predetermined threshold (Hmin2) (third embodiment).

[0143] According to this embodiment, the excavation position of the excavation target by the work tool is set based on height information of the excavation target corrected based on information such as structures placed on site, so the optimal excavation position can be selected without requiring a large computational load or calculation time.

[0144] Although embodiments of the present invention have been described in detail above, the present invention is not limited to the embodiments described above and includes various modifications. For example, the embodiments described above apply the present invention to a wheel loader equipped with a standard bucket as a work tool for excavating soil and other materials at the tip of the work device, but the application of the present invention is not limited to this and can also be applied to other work machines that perform excavation work, such as hydraulic excavators. Furthermore, the embodiments described above have been described in detail in order to explain the present invention in an easy-to-understand manner and are not necessarily limited to those that have all the configurations described.

[0145] Furthermore, each of the above configurations, functions, processing units, and processing means may be implemented in hardware, either partially or entirely, by designing them as integrated circuits, for example. Alternatively, each of the above configurations and functions may be implemented in software by having the processor interpret and execute programs that implement each function. Information such as programs, tables, and files that implement each function can be stored in memory, storage devices such as hard disks and SSDs (Solid State Drives), or recording media such as IC cards, SD cards, and DVDs.

[0146] Furthermore, the control lines and information lines shown are those deemed necessary for explanatory purposes, and not all control lines and information lines are necessarily shown in the actual product. In reality, it is safe to assume that almost all components are interconnected. [Explanation of Symbols]

[0147] 1...Bucket (working tool), 6...Lift arm, 10...Engine, 11...Hydraulic pump, 12...Control valve, 51a, 51b...Positioning device, 52a, 52e...Attitude sensor, 60...Communication interface, 71...Object detection sensor, 100...Automatic driving control device, 101...Excavation position setting unit, 110...Action decision unit, 120...Motion planning unit, 130...Motion control unit, 140...Area map holding unit, 500...Engine control device, 600...Actuator control device, 800...Process management terminal, V1...Wheel loader (working machine)

Claims

1. A tool attached to the tip of the work device for excavating the target object, A work machine comprising: an excavation position setting unit that sets the excavation position of the excavation target by the work tool based on information of the excavation target; The excavation position setting unit corrects the height information of the excavation target based on at least one piece of information, which includes information on structures arranged around the excavation target and information on the excavation area where the excavation target is located, and sets the excavation position based on the corrected height information of the excavation target.

2. A work machine according to claim 1, The excavation position setting unit is characterized by setting a priority for setting the excavation position based on at least one piece of information from the information of the structure and the information of the excavation area, and correcting the height information of the object to be excavated based on the priority.

3. A work machine according to claim 2, The excavation position setting unit is characterized by setting the priority based on the excavation direction of the object to be excavated by the work tool.

4. A work machine according to claim 3, The excavation position setting unit is characterized in that it sets the priority such that the front side has a higher priority than the back side with respect to the excavation direction of the object to be excavated by the work tool.

5. A work machine according to claim 1, The excavation position setting unit is characterized by extracting the vertex of the object to be excavated from height information of the object to be excavated, which has been corrected based on at least one piece of information from the structure information and the excavation area information, and setting the excavation position based on the height of the extracted vertex.

6. A work machine according to claim 5, The excavation position setting unit is characterized in that, when there are multiple extracted vertices, it determines whether or not excavation is possible in order from the highest vertex.

7. A work machine according to claim 5, The excavation position setting unit is characterized by estimating the volume of the excavation target that can be excavated around the apex, and determining whether or not excavation is possible based on the estimated volume of the excavation target.

8. A work machine according to claim 5, The excavation position setting unit is characterized by determining whether or not to transmit an excavation target replenishment request that requests replenishment of the excavation target based on the presence or absence of the apex or the height of the apex.

9. A tool attached to the tip of the work device for excavating the target object, A work machine comprising: an excavation position setting unit that sets the excavation position of the excavation target by the work tool based on information of the excavation target; The excavation position setting unit corrects the height information of the excavation target based on at least one piece of information from among information of structures arranged around the excavation target and information of the excavation area in which the excavation target is located, or information of another excavation target arranged around the excavation target, and sets the excavation position based on the corrected height information of the excavation target.

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