WO2025159060A1 - Control device for work machine - Google Patents

Abstract

Provided is a control device for a work machine such as a wheel loader provided with an articulated steering mechanism, the control device making it possible for the work machine to stably travel even on a slope having a gradient. Provided is a control device for a work machine that plans a target route, which is a movement route to a target position, and autonomously travels following the planned target route, wherein the control device comprises a route planning unit 120 that plans the target route on the basis of the current position of the work machine and the target position, and the route planning unit 120 corrects the target route on the basis of gradient information pertaining to a road surface on the target route.

Description

Work machine control device

The present invention relates to a control device for a work machine.

Construction machines that automatically travel to a predetermined location have been proposed for some time. Patent Document 1 discloses an automatic travel technology for wheel loaders, in which a wheel loader control device generates a travel path based on information set for the positions and vehicle orientation for each of the tasks of excavation, loading, and turning, and controls the vehicle to follow the generated travel path.

The driving route generated by such an autonomous driving control device is typically selected from multiple route candidates that can reach a specified position and vehicle orientation, using parameters such as driving distance and distance to obstacles. This makes it possible to select an efficient route with a short driving distance while avoiding contact with obstacles.

Japanese Patent Application Publication No. 10-212035

According to Patent Document 1, the positions and vehicle orientation of the digging, loading, and turning back positions on the generated driving route are determined using teaching data from positions and vehicle orientations when the vehicle was driven manually in advance. Furthermore, the driving route connecting the digging, loading, and turning back positions is realized by constructing it using a predetermined function. Specifically, a method is disclosed for drawing curved routes as circular arcs or clothoid curves. This allows for an efficient route with excellent route tracking and short driving distances.

On the other hand, because wheel loaders are work machines equipped with an articulated steering mechanism that allows the vehicle body itself to bend, the bending angle of the vehicle body constantly changes while driving, and as a result, the position of the vehicle's center of gravity also constantly changes. Therefore, if the vehicle is driven along a driving path generated without taking into account the bending angle of the vehicle body and changes in the position of the center of gravity, there is a risk that the vehicle body will lean too much, resulting in unstable behavior.

In particular, when driving on slopes with inclines, the effects of changes in the vehicle's bending angle and center of gravity become apparent, so in order to ensure stable autonomous driving, it is necessary to plan the route according to the gradient conditions of the road surface on which the vehicle will be traveling.

There is also technology that constantly monitors the vehicle's tilt and center of gravity while driving, and if the vehicle's tilt becomes too great and its behavior becomes unstable, it will regenerate (replan) the driving path or stop the vehicle. However, in work machines equipped with articulated steering mechanisms, the center of gravity of the vehicle is likely to change due to changes in the vehicle's bending angle and the condition of the load loaded in the bucket, which is a work tool. Regenerating (replanning) the driving path can change the vehicle's bending angle or the condition of the load, which can change the vehicle's center of gravity and make the vehicle's behavior even more unstable, or the vehicle's stopping control can cause the vehicle to stop frequently, resulting in reduced work efficiency. Therefore, as mentioned above, in order to achieve stable autonomous driving, it is necessary to plan in advance a path that is less likely to change the vehicle's bending angle or center of gravity (less likely to tilt) depending on the gradient conditions of the road surface on which the vehicle will be driven.

The present invention was made in consideration of the above-mentioned problems, and aims to provide a control device for a work machine, such as a wheel loader equipped with an articulated steering mechanism, that allows the machine to travel stably even on slopes with inclines.

In order to achieve the above objective, the present invention provides a control device for a work machine that plans a target route, which is a travel route to a target position, and automatically travels by following the planned target route. The control device is equipped with a route planning unit that plans the target route based on the current position of the work machine and the target position, and the route planning unit modifies the target route based on gradient information of the road surface on the target route.

The present invention makes it possible to prevent the vehicle's behavior from becoming unstable when traveling on a route that includes slopes. Issues, configurations, and advantages other than those described above will become clear from the description of the following embodiments.

1 is an external view of a work machine according to an embodiment of the present invention. 1 is a control system diagram of a work machine according to an embodiment of the present invention. FIG. 1 is a functional block diagram of an automatic driving control device according to an embodiment of the present invention. 10 is a flowchart showing a calculation process performed by a behavior management unit according to an embodiment of the present invention. 4 is a flowchart showing a calculation process performed by a path planning unit according to an embodiment of the present invention. FIG. 1 is a conceptual diagram showing the relationship between a road surface gradient vector and a target route. An example of route planning using road surface gradient vectors. An example of route planning using the height (height difference) of left and right vehicles. An example of the transition in height (height difference) of left and right vehicles when traveling along a route.

The following describes an embodiment of the present invention, taking a wheel loader as an example of a work machine, with reference to the drawings. Note that in each drawing, equivalent components are given the same reference numerals, and duplicate explanations will be omitted where appropriate.

An embodiment of the present invention will be described with reference to Figures 1 to 9.

FIG. 1 is a diagram that schematically shows the exterior of a wheel loader according to this embodiment, and FIG. 2 is a diagram that schematically shows the control system of a wheel loader according to this embodiment.

In Figure 1, the wheel loader V1 is equipped with a bucket 1, which is a work implement, at the front of the vehicle body, and a lift arm 2 that rotatably supports the bucket 1. The lift arm 2 is rotatably supported by the wheel loader V1, and the bucket 1 moves up and down as the lift arm 2 rotates. The lift arm 2 also rotatably supports a bell crank 3, and when the bell crank 3 rotates, the bucket 1 also rotates relative to the lift arm 2 via the bucket link 4.

The wheel loader V1 also has a front right tire 21FR, a front left tire 21FL, a rear right tire 21RR (Figure 2), and a rear left tire 21RL, which are driven to travel, and is also equipped with an articulated (also called articulated) steering mechanism, which turns by bending the front of the vehicle body relative to the rear of the vehicle body around an axis perpendicular to the vehicle body, creating an angle difference between the front and rear of the vehicle body.

In FIG. 2, the control system includes an engine 10 as a power source, which drives a hydraulic pump 14 and a driving force transmission device 22. The driving force transmission device 22 transmits the driving force of the engine 10 to the front right tire 21FR, the front left tire 21FL, the rear right tire 21RR, and the rear left tire 21RL via a center joint 23C, a front differential 24F, and a rear differential 24R, respectively, causing the wheel loader V1 to accelerate and travel.

Meanwhile, the hydraulic pump 14 is driven by the engine 10 to supply hydraulic oil to the control valve 15, which distributes the hydraulic oil to drive the steer cylinder 11, lift cylinder 12, bucket cylinder 13, and brakes 14F and 14R. The steer cylinder 11, lift cylinder 12, and bucket cylinder 13 expand and contract as hydraulic oil is supplied, changing the angle between the front and rear of the vehicle body, the angle of the lift arm 2 relative to the front of the vehicle body, and the angle of the bucket 1 (see also Figure 1). Additionally, when the brakes 14F and 14R are closed by hydraulic oil, the rotation of the tires 21FR, 21FL, 21RR, and 21RL is suppressed, causing the wheel loader V1 to decelerate and stop.

The control system also includes an automatic driving control device 100, an engine control device 500, a hydraulic control device 600, a travel control device 700, a user interface 60, a positioning device 51, and a load measuring device 52. The positioning device 51 acquires information on the current position and vehicle body orientation (position and orientation information) of the wheel loader V1. Here, the vehicle body orientation of the wheel loader V1 is, for example, the direction facing forward of the wheel loader V1 when the front and rear of the vehicle body of the wheel loader V1 are aligned in a straight line in the fore-and-aft direction. In this embodiment, the positioning device 51 is a Global Navigation Satellite System (GNSS), but this embodiment is not limited to this. The positioning device 51 may also be configured with the well-known Simultaneous Localization and Mapping (SLAM) using a camera or Light Detection and Ranging (LiDAR). The load measuring device 52 is configured to estimate the weight of the load in the bucket 1 (load) from the attitude of the bucket 1, which is the work tool, and the pressure of the lift cylinder 12 and bucket cylinder 13. The user interface 60 is a PC, tablet terminal, smartphone, etc., but may also be any other device that can input work instructions, as described below.

The automatic driving control device 100 generates engine control signals, hydraulic control signals, and travel control signals in response to work instructions from the user interface 60, position and orientation information from the positioning device 51, and load information from the load measuring device 52, and transmits these signals to the engine control device 500, hydraulic control device 600, and travel control device 700, respectively. In response to these signals, the engine control device 500 controls the rotation speed of the engine 10, the hydraulic control device 600 controls the opening and closing degree of the control valve 15, and the travel control device 700 controls the gear ratio and rotation direction of the driving force transmission device 22.

FIG. 3 is a functional block diagram of an autonomous driving control device 100 according to an embodiment of the present invention. In FIG. 3, the autonomous driving control device 100 includes a behavior management unit 110, a route planning unit 120, an action generation unit 130, and a road surface gradient information storage unit 140.

The behavior management unit 110 receives work instructions from the user interface 60, position and orientation information from the positioning device 51, and load information from the load measuring device 52, determines the operation mode of the wheel loader V1, and sends this to the operation generation unit 130, while also calculating the target position and sending it to the path planning unit 120. Here, the target positions are the excavation position, the turning position when moving from the excavation position to the loading position, the loading position, the turning position when moving from the loading position to the next excavation position, and the vehicle orientation at each position.

The route planning unit 120 receives the target position from the behavior management unit 110, position and orientation information from the positioning device 51, and road surface gradient information from the road surface gradient information storage unit 140, calculates the target route (also called the travel route or driving route) from the current position to the target position, and transmits it to the action generation unit 130.

The motion generation unit 130 receives the operation mode from the behavior management unit 110, the target route from the route planning unit 120, and position and orientation information from the positioning device 51, and generates the travel motion of the wheel loader V1 so that the current position information of the wheel loader V1 follows the target route. It also generates the work motion of the bucket 1, such as digging, loading, or dumping, according to the operation mode, and sends these as a travel control signal and a hydraulic control signal to the travel control device 700 and the hydraulic control device 600, respectively. The motion generation unit 130 also calculates the required engine speed from the travel motion and work motion, and sends this to the engine control device 500 as an engine control signal. For example, similar to conventional manual operation, the travel control signal may be the amount of accelerator and brake pedal operation, the amount of steering, and a forward/reverse switch switching signal, and the hydraulic control signal may be the amount of lever operation of the lift arm 2 and bucket 1.

The road surface gradient information storage unit 140 stores gradient information (road surface gradient information) of the road surface on which the wheel loader V1 travels and outputs it to the route planning unit 120. The road surface gradient information stored by the road surface gradient information storage unit 140 is, for example, information in map format, and includes information on vectors (hereinafter referred to as road surface gradient vectors) that represent the position, magnitude, and direction of the road surface gradient.

FIG. 4 is a flowchart showing the calculation processing performed by the behavior management unit 110. In FIG. 4, first, in step S1100, it is confirmed whether or not a work instruction sent from the user interface 60 has been received, and if so, the process proceeds to step S1101. The work instruction includes information such as the excavation position where earth and sand will be excavated, the loading position where the excavated earth and sand will be loaded onto a dump truck or the like, and the weight of the load to be loaded into the bucket 1.

In step S1101, the robot acquires its own position and orientation information from the positioning device 51 and load information from the load measuring device 52, and then proceeds to step S1102.

From step S1102 onwards, the target position and operation mode are selected from the load information and self-position and orientation information. First, in step S1102, the presence or absence of a load is confirmed from the load information obtained from the load measuring device 52, and if there is no load, the process proceeds to step S1103, and if there is load, the process proceeds to step S1123.

In steps S1103 and S1123, the excavation position and loading position are set as the target positions, respectively, and the process proceeds to steps S1104 and S1124.

In step S1104, it is confirmed whether the wheel loader V1's own position acquired from the positioning device 51 is equal to the excavation position information included in the work instruction, and if true, the process proceeds to S1105; if false, the process proceeds to S1115. Note that the position comparison in this step may also be made by comparing whether the wheel loader V1's own position is within a predetermined range of the excavation position.

In step S1105, the travel mode is selected as the operating mode. This allows the wheel loader V1 to perform travel operations with the target position as the excavation position.

Similarly, in step S1115, excavation mode is selected as the operating mode. This allows the wheel loader V1 to perform excavation operations with the target position as the excavation position.

In step S1124, it is confirmed whether the wheel loader V1's own position acquired from the positioning device 51 is equal to the loading position information included in the work instruction, and if true, the process proceeds to S1125; if false, the process proceeds to S1135. Note that the position comparison in this step may also be made by comparing whether the wheel loader V1's own position is within a specified range of the loading position.

In step S1125, the transport mode is selected as the operation mode. This allows the wheel loader V1 to perform transport operations with the target position as the loading position.

Similarly, in step S1135, loading mode is selected as the operation mode. This allows the wheel loader V1 to perform loading operations with the target position as the loading position.

FIG. 5 is a flowchart showing the calculation processing performed by the route planning unit 120. In FIG. 5, first, in step S1200, it is confirmed whether or not a target position transmitted from the behavior management unit 110 has been received, and if so, the process proceeds to step S1201.

In step S1201, road surface gradient information is obtained from the road surface gradient information storage unit 140. The road surface gradient information includes information on the position, direction, and magnitude of the road surface gradient (road surface gradient vector).

In step S1202, a driving cost is set based on the magnitude of the road surface gradient. Driving cost is one of the indicators used in route planning algorithms such as the potential method. By dividing the driving area into grids and setting a cost for each grid as information representing the ease (or difficulty) of driving, it is possible to calculate the cost of the entire route passing through the grid. Generally, in order to plan a route that reaches the target position while avoiding obstacles, grids that correspond to obstacles or their surroundings are set to have a high cost. In this step, in addition to the traditional obstacles, a high driving cost is set for grids that correspond to areas with steep road surface gradients.

In step S1203, a target route from the current position to the target position is planned using a potential method such as Dijkstra's algorithm, using the travel cost set in step S1202, and the process proceeds to step S1204.

In step S1204, it is determined whether the planned target route includes a road surface gradient of a predetermined value or more. If true, the process proceeds to step S1205; if false, the process proceeds to step S1510. In other words, it is determined whether or not to perform processing from step S1205 onwards based on the magnitude of the road surface gradient included in the planned target route.

In step S1205, it is determined whether the planned target route is directly facing the road surface gradient; if true, the process proceeds to step S1206; if false, the process proceeds to step S1510.

A specific method for determining whether the target route is directly facing the road surface gradient performed in step S1205 will be described using the relationship diagram between the road surface gradient vector and the target route shown in FIG. 6 . The road surface gradient information stored in the road surface gradient information storage unit 140 includes information on a vector (road surface gradient vector) that represents the position, magnitude, and direction of the road surface gradient. When the direction of the road surface gradient vector and the direction of the target route approximately coincide, it can be determined that the target route is directly facing the road surface gradient. In this embodiment, if the angle (angular difference) _θS between the direction of the target route and the direction of the road surface gradient vector is equal to or smaller than a predetermined value, it is determined that the target route is directly facing the road surface gradient, and the process proceeds to step S1510. Conversely, if the angle (angular difference) _θS between the direction of the target route and the direction of the road surface gradient vector is greater than a predetermined value, it is determined that the target route is not directly facing the road surface gradient, and the process proceeds to step S1206.

In step S1206, a gradient section (a road section of a predetermined length) on the target route that has a road surface gradient of a predetermined value or more but is not directly facing the road surface gradient is targeted, and a determination is made as to whether there is room to change the start point of the gradient section so that the target route is directly facing the road surface gradient. For example, the road width at the start point of the gradient section is compared with the vehicle width of the wheel loader V1, and if there is room for the road width in the direction in which _θS of the gradient section becomes smaller, it is determined that there is room to change the start point of the gradient section, and the process proceeds to step S1208. If it is determined that there is no room to change the start point of the gradient section, the process proceeds to step S1307.

In step S1307, in the same manner as in step S1206, it is determined whether there is room to change the end point of the gradient section in a direction that reduces _θS of the gradient section relative to the end point. If there is room to change the end point of the gradient section, the process proceeds to step S1308; if there is no room to change the end point of the gradient section, the process proceeds to step S1410.

In step S1208, for road sections where there is room to change the starting point, the end point of the road section is set as a waypoint, and the process proceeds to step S1209.

Similarly, in step S1308, for road sections where there is room to change the end point, the start point of the road section is set as a waypoint, and the process proceeds to step S1209.

In step S1209, the target route is corrected so that it passes through the set via point and faces the road surface gradient of the gradient section (the angle _θS between the direction of the target route and the direction of the road surface gradient vector is equal to or less than a predetermined value), and the process returns to step S1204. In other words, either the start point or the end point of the road surface gradient section is set as a via point, and the target route is corrected so that it passes through the set via point and faces the road surface gradient of the gradient section (the angle _θS between the direction of the target route and the direction of the road surface gradient vector is equal to or less than a predetermined value). The method of correcting the target route will be described later.

In step S1510, it is determined that the target route does not include a road surface gradient of a predetermined value or greater (false in S1204), or that the target route includes a road surface gradient of a predetermined value or greater but is directly facing that road surface gradient (false in S1205), and the fact that the route planning was successful and the planned target route are sent (notified) to the user interface 60 and the motion generation unit 130.

In step S1410, since the target route could not be corrected to face the road surface gradient included in the target route that is equal to or greater than the predetermined value (false in S1206 and S1307), a message is sent (notified) to the user interface 60 indicating that the route planning failed and requesting a change (review) of the target position.

Next, we will explain how to correct the target route in step S1209 using Figure 7.

Figure 7 is a schematic diagram showing road surface gradient vectors and target routes. In Figure 7, solid lines represent contour lines, and the arrows extending from the center of each grid are road surface gradient vectors. The road surface gradient vector indicates the direction of the road surface gradient at that position by the direction of the arrow, and the magnitude of the road surface gradient by the length (magnitude) of the arrow.

The route (route a), shown by the dotted arrow, planned using a conventional route planning method that does not take road surface gradient into account is basically a route planned to shorten the route length to the target position while avoiding obstacles. As a result, a route is planned that does not directly confront the road surface gradient.

The route indicated by the solid arrow (route b) is a route in which the intersection of the end point of the gradient section and the route is set as a waypoint, and the start point of the gradient section is set as a waypoint so that the target route for the gradient section passes through the waypoint and follows the direction of the road surface gradient vector (the angle _θS between them is equal to or less than a predetermined value). Note that although the end point of the gradient section is set as the waypoint here, if there is no room to change the start point of the gradient section, as shown in steps S1206 and S1307 above, the start point of the gradient section may be set as the waypoint and the end point of the gradient section may be changed so that it follows the direction of the road surface gradient vector.

Next, another example of the facing determination method for the road surface gradient of the target route performed in step S1205 will be described using Figures 8 and 9. The difference from the facing determination method (Figure 6) that uses the angle _θS between the direction of the road surface gradient vector and the direction of the target route is that the difference in elevation between the left and right wheels (at least one pair of left and right wheels) (for example, the centers of the left and right wheels) of the wheel loader V1 is used. Figure 8 is a diagram that schematically shows a route on a road surface gradient, and Figure 9 is a diagram that schematically shows the transition of the difference in elevation between the left and right wheels of the wheel loader V1 when traveling on the route.

As in Figure 7, the route indicated by the dotted arrow (route a) is an example of a route planned using a conventional route planning method that does not take road surface gradient into consideration, and therefore the route is planned so as to basically shorten the route length to the target position while avoiding obstacles. This route a does not face the road surface gradient, i.e., it approaches the road surface gradient at an angle, so as shown in Figure 9, a difference in elevation occurs between the left and right wheels of the wheel loader V1 when traveling on a slope. If the difference in elevation between the left and right wheels is equal to or greater than the road surface gradient judgment threshold, it is determined that the target route does not face the road surface gradient (step S1205 in Figure 5), and that road surface gradient section is subject to correction. The specific method of correcting the target route is the same as the method described in Figure 7, where either the start point or the end point of the road surface gradient section is set as a waypoint, and the other point is set as a waypoint so that the waypoint is passed and the difference in elevation between the left and right wheels of the wheel loader V1 is equal to or less than the road surface gradient judgment threshold. The route indicated by the solid arrow (route b) is a target route that has been modified so that the difference in height between the left and right wheels of the wheel loader V1 is equal to or less than the road gradient judgment threshold, with the end point of the road gradient section as a via point.

As described above, by planning a target route that faces a slope, it is possible to prevent the vehicle's behavior from becoming unstable when traveling up a slope.

[summary]
As explained above, the control device (automatic driving control device 100) of a work machine (wheel loader V1) in this embodiment is a control device for a work machine that plans a target route, which is a movement route to a target position (set by the behavior management unit 110) (in other words, a movement route for moving the work machine from its current position to the target position), and automatically travels by following the planned target route, and the control device is equipped with a route planning unit 120 that plans the target route based on the current position of the work machine (acquired by the positioning device 51) and the target position, and the route planning unit 120 corrects the target route based on gradient information of the road surface on the target route.

The route planning unit 120 corrects the target route based on the angle difference (the angle θ _S ) between the direction of the target route and the direction of the gradient of the road surface on the target route.

The route planning unit 120 corrects the target route so that the angle difference (the angle θ _S ) between the direction of the target route and the direction of the gradient of the road surface on the target route is equal to or less than a predetermined value (so that the target route faces the gradient of the road surface) (step S1205 and subsequent steps).

The route planning unit 120 determines whether to modify the target route based on the magnitude of the gradient of the road surface on the target route (step S1204).

The route planning unit 120 determines whether the angular difference (the formed angle θ _S ) between the direction of the target route and the direction of the gradient of the road surface on the target route exceeds a predetermined value (the target route is not directly facing the road surface gradient) (step S1205), and if it determines that the angular difference exceeds the predetermined value (the target route is not directly facing the road surface gradient) (true in step S1205), it sets either the start point or the end point of the target route in the section of the road surface gradient as a via point (steps S1208, S1308), and corrects the target route so that it passes through the via point and the angular difference becomes equal to or less than the predetermined value (the target route is directly facing the road surface gradient of the gradient section) (step S1209).

The gradient information of the road surface on the target route includes a road surface gradient vector containing information on the position, direction, and magnitude of the gradient of the road surface. The route planning unit 120 compares the direction of the target route with the direction of the road surface gradient vector (FIG. 6), and determines whether the angular difference (angle θ _S ) between the direction of the target route and the direction of the road surface gradient on the target route exceeds a predetermined value (i.e., whether the target route is not directly facing the road surface gradient) (step S1205).If it is determined that the angular difference exceeds the predetermined value (i.e., the target route is not directly facing the road surface gradient) (true in step S1205), either the start point or the end point of the target route in the section with the road surface gradient is set as a via point (steps S1208, S1308), and the target route is corrected so that it passes through the via point and the angular difference becomes equal to or less than the predetermined value (i.e., the target route is directly facing the road surface gradient of the gradient section) (step S1209).

The work machine has at least one pair of left and right wheels, and the route planning unit 120 determines whether the angular difference (angle θ S ) between the direction of the target route and the direction of the road surface gradient on the target route exceeds a predetermined value (the target route is not directly facing the road surface gradient) based on a comparison ( FIG. ₉ ) between the difference in elevation between the pair of left and right wheels and a preset road surface gradient determination threshold (step S1205).If it is determined that the angular difference exceeds the predetermined value (the target route is not directly facing the road surface gradient) (true in step S1205), either the start point or the end point of the target route in the section with the road surface gradient is set as a waypoint (steps S1208, S1308), and the target route is corrected so that it passes through the waypoint and the angular difference becomes equal to or less than the predetermined value (the target route is directly facing the road surface gradient of the gradient section) (step S1209).

The route planning unit 120 determines whether to modify the target route based on the magnitude of the gradient of the road surface on the target route (step S1204).

The control device includes an operation generation unit 130 that generates control signals for causing the work machine to travel while following the target route planned by the route planning unit 120, and the route planning unit 120 determines whether the target route includes a gradient of the road surface that is equal to or greater than the predetermined magnitude (step S1204), and if it is determined that the target route includes a gradient of the road surface that is equal to or greater than the predetermined magnitude (true in step S1204), calculates an angle difference (formed angle θ _S) between the direction of the target route and the direction of the gradient of the road surface. ) exceeds a predetermined value (the target route is not directly facing the road surface gradient) (step S1205), and if it is determined that the angle difference exceeds the predetermined value (the target route is not directly facing the road surface gradient) (step S1205: true), either the start point or the end point of the target route in the section of the road surface gradient is set as a via point (steps S1208, S1308), and the target route is adjusted so that the target route passes through the via point and the angle difference becomes equal to or less than the predetermined value (the target route is directly facing the road surface gradient of the gradient section). (step S1209), and if it is determined that the target route does not include a gradient of the road surface equal to or greater than the predetermined magnitude (false in step S1204), or if it is determined that the target route includes a gradient of the road surface equal to or greater than the predetermined magnitude but the angular difference does not exceed the predetermined value (is equal to or less than the predetermined value) (the target route is directly facing the road surface gradient) (false in step S1205), the target route is output to the action generation unit 130 (as the final target route) without being modified (step S1510).

Furthermore, the work machine is equipped with an articulated (bending) steering mechanism.

According to this embodiment, the vehicle can travel stably on slopes with inclines, preventing the vehicle's behavior from becoming unstable when traveling on routes that include slopes.

Although the above describes in detail an embodiment of the present invention, the present invention is not limited to the above embodiment and includes various modifications. For example, while the above embodiment applies the present invention to a wheel loader, the application of the present invention is not limited to this and can also be applied to work machines such as dump trucks. Furthermore, the above embodiment has been described in detail to clearly explain the present invention, and the present invention is not necessarily limited to having all of the configurations described.

Furthermore, some or all of the above-mentioned configurations, functions, processing units, processing means, etc. may be realized in hardware, for example by designing them as integrated circuits. Furthermore, the above-mentioned configurations, functions, etc. may be realized in software by a processor interpreting and executing programs that realize each function. Information such as programs, tables, and files that realize 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.

Furthermore, the control and information lines shown are those considered necessary for the explanation, and do not necessarily represent all control and information lines on the product. In reality, it is safe to assume that almost all components are interconnected.

1...Bucket, 2...Lift arm, 3...Bell crank, 4...Bucket link, 51...Positioning device, 52...Load measuring device, 60...User interface, 100...Autonomous driving control device (control device), 110...Behavior management unit, 120...Path planning unit, 130...Movement generation unit, 140...Road surface gradient information storage unit, 500...Engine control device, 600...Hydraulic control device, 700...Travel control device, V1...Wheel loader (construction machine)

Claims (10)

A control device for a work machine that plans a target route, which is a movement route to a target position, and automatically travels by following the planned target route,
the control device includes a route planning unit that plans the target route based on the current position of the work machine and the target position,
A control device for a work machine, wherein the route planning unit corrects the target route based on gradient information of a road surface on the target route. The control device for a work machine according to claim 1,
A control device for a work machine, wherein the route planning unit corrects the target route based on an angular difference between the direction of the target route and the direction of a gradient of a road surface on the target route. The control device for a work machine according to claim 2,
A control device for a work machine, characterized in that the route planning unit corrects the target route so that an angular difference between the direction of the target route and the direction of a gradient of a road surface on the target route is equal to or less than a predetermined value. The control device for a work machine according to claim 2,
The control device for a work machine, wherein the route planning unit determines whether or not to modify the target route based on the magnitude of a gradient of a road surface on the target route. The control device for a work machine according to claim 1,
a control device for a work machine, characterized in that the route planning unit determines whether an angular difference between the direction of the target route and the direction of the gradient of a road surface on the target route exceeds a predetermined value, and if it determines that the angular difference exceeds the predetermined value, sets either the start point or the end point of the target route in the section of the road surface gradient as a via point, and corrects the target route so that it passes through the via point and the angular difference is not more than the predetermined value. The control device for a work machine according to claim 5,
the gradient information of the road surface on the target route includes a road surface gradient vector including information on the position, direction, and magnitude of the gradient of the road surface;
The control device for a work machine, wherein the route planning unit determines whether the angle difference exceeds a predetermined value based on a comparison between the direction of the target route and the direction of the road surface gradient vector. The control device for a work machine according to claim 1,
The work machine has at least one pair of left and right wheels,
a control device for a work machine, characterized in that the route planning unit determines whether or not the angular difference between the direction of the target route and the direction of the gradient of the road surface on the target route exceeds a predetermined value based on a comparison of the difference in elevation between the pair of left and right wheels with a preset road surface gradient determination threshold, and if it determines that the angular difference exceeds the predetermined value, sets either the start point or the end point of the target route in the section of the road surface gradient as a via point, and corrects the target route so that it passes through the via point and the angular difference is not more than the predetermined value. The control device for a work machine according to claim 5,
The control device for a work machine, wherein the route planning unit determines whether or not to modify the target route based on the magnitude of a gradient of a road surface on the target route. The control device for a work machine according to claim 8,
the control device includes an operation generation unit that generates a control signal for causing the work machine to travel while following the target path planned by the path planner,
The route planning unit
determining whether the target route includes a gradient of the road surface that is equal to or greater than a predetermined magnitude;
When it is determined that the target route includes a gradient of the road surface equal to or greater than the predetermined magnitude, it is determined whether or not an angular difference between the direction of the target route and the direction of the gradient of the road surface exceeds a predetermined value, and when it is determined that the angular difference exceeds the predetermined value, it sets either a start point or an end point of the target route in the section of the gradient of the road surface as a via point, and corrects the target route so that it passes through the via point and the angular difference becomes equal to or less than the predetermined value;
A control device for a work machine, characterized in that if it is determined that the target route does not include a gradient of the road surface that is equal to or greater than the predetermined magnitude, or if it is determined that the target route includes a gradient of the road surface that is equal to or greater than the predetermined magnitude and it is determined that the angular difference does not exceed the predetermined value, the control device outputs the target route to the operation generation unit without modifying it. The control device for a work machine according to claim 1,
10. A control device for a work machine, wherein the work machine is a work machine equipped with an articulated type steering mechanism.