JP7722829B2 - Work machine control system and work machine - Google Patents

Description

The present invention relates to a work machine control system and a work machine equipped with such a work machine control system.

A work machine and a work machine control system have been proposed that automatically excavates an object and loads it at a designated loading position.

For example, Patent Document 1 discloses an automatic excavation technology that "includes a measuring instrument for determining the distance from the excavator to the excavation object and the loading object, an excavation object recognition means for recognizing the three-dimensional shape of the excavation object based on the output of the measuring instrument, an excavation target position calculation means for calculating the excavation target position of the recognized excavation object, a loading target position calculation means for calculating the relative position of the loading object with respect to the excavator and the relative attitude of the excavator with respect to the loading object based on the output of the measuring instrument, and for calculating the loading target position based on the calculation results, an automatic positioning means for automatically positioning a work machine at the calculated excavation target position and loading target position, an automatic excavation control means for automatically excavating at the excavation target position, and an automatic loading control means for automatically loading the excavated object at the loading target position (abstract excerpt)."

Japanese Patent Application Publication No. 10-88625

When excavating within a work area, the amount of excavation may be either excessive or insufficient. However, the technology disclosed in Patent Document 1 does not anticipate such situations. Therefore, the technology disclosed in Patent Document 1 does not allow for appropriate control of the work machine according to the amount of excavation.

The present invention was made in consideration of the above circumstances, and aims to provide technology that appropriately controls a work machine according to the amount of excavation when automatically excavating an object to be excavated, transporting it to a target location, and loading it.

In order to achieve the above-mentioned object, a representative aspect of the present invention is a work machine control system having an automatic driving control device that controls the operation of a work machine having a work implement, a load acquisition device that measures the live load of an object in the work implement, and a positioning device that acquires the current position of the work machine, wherein the automatic driving control device comprises: a behavior management unit that sets a target position to which the work machine is to move; a route planning unit that generates a target route that is a travel route between the current position acquired by the positioning device and the target position set by the behavior management unit; and an operation generation unit that generates a control signal to operate the work machine according to the target route generated by the route planning unit, wherein the behavior management unit determines the target position in accordance with the live load acquired by the load acquisition device, and the operation generation unit generates a control signal to cause the work machine to travel to the target position and load the object in the work implement onto a loading target.

The present invention allows for the automatic excavation of an object to be excavated, transported to a target location, and loaded, with the work machine appropriately controlled according to the amount of excavation. Issues, configurations, and advantages other than those described above will become clear from the description of the following embodiments.

FIG. 1 is an explanatory diagram for explaining an overview of a first embodiment. 1 is a schematic diagram of the appearance of a wheel loader according to a first embodiment. FIG. FIG. 1 is a configuration diagram of a control system for a wheel loader according to a first embodiment. FIG. 2 is a hardware configuration diagram of the control system according to the first embodiment. FIG. 1 is a functional block diagram of an automatic driving control device according to a first embodiment. 4A to 4C are explanatory diagrams for explaining map data according to the first embodiment; FIG. 1A is an explanatory diagram for explaining an example of a work instruction according to the first embodiment, and FIGS. 1B to 1D are explanatory diagrams for explaining examples of a target route according to the first embodiment. 4A is an explanatory diagram for explaining an example of upper and lower limit data of excavation volume according to the first embodiment, and FIG. 4B is an explanatory diagram for explaining an example of lower limit data of loading volume according to the first embodiment. 10 is a flowchart of a behavior management process according to the first embodiment. FIG. 11 is an explanatory diagram for explaining an example of lower limit correction data according to the second embodiment. 10 is a flowchart of a behavior management process according to a second embodiment.

An embodiment of a work machine assistance system according to the present invention will be described below with reference to the drawings.

<<First Embodiment>>
First, an overview of the first embodiment will be described using Fig. 1. In this embodiment, a work machine 100 such as a wheel loader that autonomously travels within a work area 300 excavates an excavation target 310 and transports the excavated object to a loading target 320 in accordance with work instructions. The loading target 320 is a hopper, a dump truck, or the like.

The following describes the work machine 100 and its control system that achieves this. Here, we will use a wheel loader as an example of the work machine 100.

Figure 2 is a diagram showing a schematic view of the exterior of the wheel loader 100 of this embodiment, and Figure 3 is a diagram showing the control system 180 of the wheel loader 100 of this embodiment.

The wheel loader 100 comprises a vehicle body 110 and an articulated work machine 120 attached to the front of the vehicle body 110.

The work implement 120 is a work device driven by at least one actuator. The work implement 120 shown in FIG. 2 includes a bucket 121, a lift arm 122, a bell crank 123, a bucket link 124, a lift cylinder 125, a bucket cylinder 126, and a steering cylinder 112.

The bucket 121 is a work implement mounted at the front of the vehicle body. The lift cylinder 125 and bucket cylinder 126 are hydraulic actuators (hydraulic cylinders) that drive the bucket 121 and lift arm 122, respectively, and are attached between the work implement 120 and the vehicle body 110. One lift arm 122 and one lift cylinder 125 are mounted on each side of the vehicle body 110.

The lift arm 122 is rotatably supported on the vehicle body 110 and rotates vertically (moves up and down) in response to the extension and retraction of the lift cylinder 125. The bucket 121 also rotates (dumps or crowds) in response to the extension and retraction of the bucket cylinder 126.

One end of the lift cylinder 125 is connected to the lift arm 122, and the other end is connected to the vehicle body 110. One end of the bucket cylinder 126 is connected to the bell crank 123, and the other end is connected to the vehicle body 110. The link mechanism that operates the bucket 121 of the wheel loader 100 shown in Figure 2 is a Z-link type (bell crank type) that uses the bell crank 123.

The vehicle body 110 is provided with four wheels (front right tire 131FR, front left tire 131FL, rear right tire 131RR (see Figure 2), and rear left tire 131RL). Hereinafter, unless there is a need to distinguish between them, they will be collectively referred to as tires 131. Each tire 131 is driven by a power transmission device powered by the engine 111 (see Figure 3). Driving force is transmitted to the ground via each tire 131, causing the wheel loader 100 to move forward or backward.

The wheel loader 100 also has an articulated steering mechanism, and turns by creating an angle difference between the front and rear of the vehicle body around the vertical axis of the vehicle body as the steering cylinder 112 extends and retracts.

As shown in FIG. 3, the wheel loader 100 includes an engine 111, a steering cylinder 112, a driving force transmission device 113, a hydraulic pump 114, a control valve 115, a center joint 132C, brakes 133F and 133R, a front differential 134F, a rear differential 134R, a positioning device 141, a load acquisition device 142, a control system 180, and a user interface 190.

As shown in FIG. 3, the control system 180 also includes an automatic driving control device 200, a hydraulic control device 160, an engine control device 150, and a driving control device 170.

The engine 111 is the power source for the wheel loader 100. The engine 111 drives the hydraulic pump 114 and the driving force transmission device 113.

The driving force transmission device 113 transmits the driving force of the engine 111 to the front right tire 131FR and front left tire 131FL via the center joint 132C and front differential 134F, and to the rear right tire 131RR and rear left tire 131RL via the center joint 132C and rear differential 134R, allowing the wheel loader 100 to accelerate.

The hydraulic pump 114 is driven by the engine 111 and supplies hydraulic oil to the control valve 115. The hydraulic oil is distributed by the control valve 115 to drive the steering cylinder 112, lift cylinder 125, bucket cylinder 126, and brakes 133F and 133R. The steering cylinder 112, lift cylinder 125, and bucket cylinder 126 expand and contract with the supply of hydraulic oil, changing the angle between the front and rear of the vehicle body, the angle of the lift arm 122 relative to the front of the vehicle body, and the angle of the bucket 121. Closing the brakes 133F and 133R with hydraulic oil also suppresses the rotation of the tires 131FR, 131FL, 131RR, and 131RL, causing the wheel loader 100 to decelerate and stop.

The positioning device 141 acquires current position information for the wheel loader 100. The positioning device 141 is a Global Navigation Satellite System (GNSS). However, the positioning device 141 is not limited to this. The positioning device 141 may also perform positioning using the well-known Simultaneous Localization and Mapping (SLAM) method, using a camera or Light Detection and Ranging (LiDAR).

The load acquisition device 142 acquires live load information for the bucket 121. The load acquisition device 142 includes, for example, a pressure sensor attached to the lift cylinder 125 and a calculation device. The pressure sensor acquires the bottom pressure of the lift cylinder 125, and the calculation device calculates the live load of the object excavated by the bucket 121 from the bottom pressure. The calculation device, for example, detects the weight of the bucket 121 when empty in advance, and calculates the live load by subtracting the weight of the bucket 121 from the total weight including the bucket 121 and the load. The calculation result is sent to the automatic driving control device 200 as load information. Note that the sensor used to acquire the load is not limited to a pressure sensor. For example, a strain sensor or the like may be used.

The user interface 190 may be a PC, tablet terminal, smartphone, or other device that can input work instructions, as described below.

The automatic driving control device 200 generates engine control signals, hydraulic control signals, and driving control signals in response to work instructions from the user interface 190, current location information from the positioning device 141, and load information from the load acquisition device 142, and transmits these signals to the engine control device 150, hydraulic control device 160, and driving control device 170, respectively.

In response to these signals, the engine control device 150 controls the engine 111 rotation speed, the hydraulic control device 160 controls the opening and closing degree of the control valve 115, and the driving control device 170 controls the gear ratio and rotation direction of the driving force transmission device 113.

The control system 180 is a computer that executes various information processing related to the operation of the wheel loader 100, and is realized, for example, by a microcomputer.

Figure 4 shows an example of the hardware configuration of the control system 180. The control system 180 includes a CPU (Central Processing Unit) 221, memory 182, storage device 183, and input/output interface (I/F) 184. It may also include a communication interface (I/F) 185. The CPU 181, memory 182, and storage device 183 may be provided for each section within the control system 180. Multiple components may be shared.

CPU 181 loads programs stored in storage device 183 into memory 182 and executes them. The memory is, for example, RAM (Random Access Memory), which functions as a work area. Storage device 183 is ROM (Read Only Memory), flash memory, etc., and stores programs, data used in CPU 181 processing, data generated during processing, data generated by processing, etc.

In this embodiment, each function of the control system 180 is realized, for example, by the CPU 181 loading a program stored in the storage device 183 into the memory 182 and executing it.

The input/output I/F 184 is an interface for inputting and outputting data. In this embodiment, it inputs and outputs data to and from the user interface 190. In this embodiment, the operator of the wheel loader 100 inputs work instructions via the user interface 190.

Note that the storage device 183 includes semiconductor memory such as ROM and flash memory, but may instead include a magnetic storage device such as a hard disk drive.

Next, the automatic driving control device 200 will be described. Figure 5 is a functional block diagram of the automatic driving control device 200 of this embodiment. The automatic driving control device 200 includes a behavior management unit 211, a route planning unit 212, and an action generation unit 213. The automatic driving control device 200 also includes map data 220.

If instructions are received externally without going through the user interface 190, a receiving unit is further provided.

The behavior management unit 211 determines a target position and transmits it to the path planning unit 212. The behavior management unit 211 also acquires work instructions, the current position, load information, and the target path, and determines the operating mode of the wheel loader 100. Furthermore, when the wheel loader 100 performs excavation, the behavior management unit 211 of this embodiment uses the load information to determine whether the excavation amount is appropriate. Then, the target position is determined based on the determination result. Therefore, the behavior management unit 211 of this embodiment calculates the target excavation amount (target live load) WB, and its upper limit (excavation amount upper limit; upper limit value) WBmax and lower limit (excavation amount lower limit; lower limit value) WBmin.

When determining the operation mode, the behavior management unit 211 acquires work instructions from the user interface 190. It also acquires the current location from the positioning device 141. It also acquires load information from the load acquisition device 142. It then acquires the target route from the route planning unit 212. The behavior management unit 211 also transmits the determined operation mode to the operation generation unit 213 and also transmits it to the user interface 190 as notification information.

In this embodiment, the operating modes include, for example, a travel mode, an excavation mode, a loading mode, and a dumping mode. The travel mode is a mode in which the wheel loader 100 travels. Here, "traveling" refers to, for example, accelerating and decelerating the vehicle body 110 and extending and retracting the steering cylinder 112, thereby causing the wheel loader 100 to travel along a target path. The excavation mode, loading mode, and dumping mode are modes in which the wheel loader 100 excavates, loads, and dumps soil, respectively. Here, "excavating" refers to, for example, accelerating and decelerating the vehicle body 110 to plunge the bucket 121 into the excavation target, and then intermittently extending the lift cylinder 125 and the bucket cylinder 126 to raise the lift arm 122 and intermittently crowd the bucket 121 until it reaches a full crowd state, thereby scooping the excavation target into the bucket 121. Loading is an operation in which, for example, while accelerating or decelerating the vehicle body 110, the lift cylinder 125 is extended to approach the loading target, thereby raising the lift arm 122 and bringing the bucket 121 above the loading target, and the bucket cylinder 126 is then retracted to dump the bucket 121 and drop the object in the bucket 121 onto the loading target. Discharging soil is an operation in which, for example, the bucket cylinder 126 is retracted at the soil release position to dump the bucket 121 and drop the object in the bucket 121 to the soil release position. When the operation generation unit 213, described later, receives instructions for these operation modes from the behavior management unit 211, it outputs predetermined control signals to each unit according to each operation mode, thereby controlling the operation of the wheel loader 100.

The route planning unit 212 uses the map data 220 to calculate a target route, which is the travel route from the current position of the wheel loader 100 to the target position, and transmits this to the behavior management unit 211 and the action generation unit 213. The route planning unit 212 receives the target position from the behavior management unit 211. It also receives the current position from the positioning device 141.

In travel mode, the operation generation unit 213 generates a travel operation signal to cause the wheel loader 100 to travel from the current position to the target position along the target route. The operation generation unit 213 transmits the travel operation signal to the travel control device 170 as a travel control signal and to the hydraulic control device 160 as a hydraulic control signal. The operation generation unit 213 also generates work operation signals for the drive force transmission device 113 and each hydraulic cylinder to perform excavation, loading, or soil dumping depending on the operation mode.

The motion generation unit 213 also calculates the required engine speed from the driving motion and working motion, and transmits this as an engine control signal to the engine control device 150. For example, similar to conventional manual operation, the driving control signal may be the amount of accelerator and brake pedal operation, the amount of steering operation device operation, and a forward/reverse switch switching signal. Furthermore, the hydraulic control signal may be the amount of lever operation for the lift arm 122 and bucket 121.

Next, the map data 220 will be described. The map data 220 is stored in advance in the storage device 183. Figure 6(a) is a diagram for explaining the map data 220 of this embodiment, and Figures 6(b) and 6(c) are examples of the map data 220 of this embodiment.

Map data 220 includes multiple points (nodes) within the work area and line segments (arcs) connecting them. For example, when the work area is defined by the coordinate system shown in FIG. 4(a), map data 220 includes coordinates 222 and attributes 223 of each point 221, as shown in FIG. 6(b), and information on endpoints 225, 226 of each line segment 224, as shown in FIG. 6(c). Note that Q1 and Q2 in the figure are excavation targets, R1 and R2 are loading targets, and O1 is an obstacle.

Next, we will explain the work instructions 230 and target route 240.

Figure 7(a) shows an example of a work instruction 230. The work instruction 230 includes, for example, an identifier (ID) 231 assigned to each work instruction, an object type 232, a target loading amount (target loading load) 233, a loading position 234, an excavation position 235, and a dumping position 236. The behavior management unit 211 carries out this work instruction 230 each time it is received from the user interface 190.

For example, work instruction 230 with identifier Ins01 instructs to excavate object M1 at excavation position Q1, load it at loading position R1, and complete the work when the loading amount reaches W1. Note that in work instruction 230 with identifier Ins01, if the excavation amount is insufficient or excessive, the soil release position 236 where the soil is released is the same position as excavation position Q1.

When the behavior management unit 211 receives this work instruction 230 with identifier Ins01, it first sets the operation mode to traveling mode, sets the excavation position Q1 (p8) as the target position, and transmits it to the path planning unit 212.

The route planning unit 212 generates a target route 240 from the current position to the target position p8 and transmits it to the behavior management unit 211 and the action generation unit 213. Here, when the current position is p0, an example of the target route 240 generated by the route planning unit 212 is shown in Figure 7(b). As shown in this figure, the target route 240 includes passing points 241 from the current position to the target position, including these positions, and an FNR 242 that indicates the traveling direction between each point. In the FNR 242, forward travel is represented by F and reverse travel is represented by R.

In executing this work instruction 230, the behavior management unit 211 of this embodiment determines the target position after excavation based on the live load information acquired by the load acquisition device 142. For example, if the actual excavation volume determined by the live load information is less than the excavation volume upper limit WBmax and greater than or equal to the excavation volume lower limit WBmin, the loading position 234 is set as the target position. In all other cases, the soil discharge position 236 is set as the target position.

In addition, multiple work instructions 230 may be received at once. In this case, the behavior management unit 211 will execute the multiple work instructions sequentially.

Next, we will explain how the behavior management unit 211 of this embodiment calculates the target excavation volume WB and its upper limit (excavation volume upper limit) WBmax and lower limit (excavation volume lower limit) WBmin.

The target excavation volume WB is determined by the target loading volume (target loading weight) WT of the work instruction 230, the current loading volume WA, and the standard excavation volume WS of the bucket 121 of the wheel loader 100. The current loading volume WA is obtained by adding the excavation volume up to the current time (actual excavation volume). The actual excavation volume is the load weight information of the bucket 121 acquired from the load acquisition device 142.

The behavior management unit 211 first calculates the remaining loading amount WR, which is the difference between the target loading amount WT and the already loaded amount WA. Then, it compares the remaining loading amount WR with the standard excavation amount WS, and sets the smaller value as the target excavation amount WB. The behavior management unit 211 calculates and updates the target excavation amount WB using this procedure each time loading is completed.

This is to excavate as much as possible in one excavation without exceeding the standard excavation volume. Excavating as much as possible is done to reduce the number of operations, i.e., the total work time, and keeping the excavation volume within the standard excavation volume is done to prevent spillage of the load.

For example, if the target loading volume WT is 10 tons and the standard excavation volume WS of the bucket 121 is 4 tons, the first target excavation volume WB is 0 because the amount already loaded is 0, and the remaining loading volume WR is 10 tons. Therefore, the target excavation volume WB is calculated as 4 tons, which is the smaller of the remaining loading volume WR (10 tons) and the standard excavation volume WS (4 tons). The second target excavation volume WB is calculated as 4 tons, which is the smaller of the remaining loading volume WR (10 tons - 4 tons = 6 tons) and the standard excavation volume WS (4 tons). The third target excavation volume WB is calculated as 2 tons, which is the smaller of the remaining loading volume WR (6 tons - 4 tons = 2 tons) and the standard excavation volume WS (4 tons).

Furthermore, once the target excavation volume WB is determined, the behavior management unit 211 identifies the upper excavation volume limit WBmax and the lower excavation volume limit WBmin. The lower excavation volume limit WBmin is determined by the target route distance (route distance) L1. An example of the relationship between the target excavation volume WB, the upper excavation volume limit WBmax, the lower excavation volume limit WBmin, and the route distance L1 is shown in Figure 8(a). This data is stored in advance in the storage device 183, etc., as upper and lower excavation volume limit data 510.

As shown in this diagram, the excavation volume upper limit WBmax is a value obtained by adding a predetermined fixed margin (upper limit margin) to the target excavation volume WB. The upper limit margin is specified, for example, as a percentage of the target excavation volume WB. The upper limit margin may be changed, for example, according to the requirements of the loading party (dump truck). In this case, for a 10-ton truck with an upper limit margin of 1 ton, the upper limit margin is specified as 10%, for example.

The excavation volume lower limit WBmin is the target excavation volume WB minus a margin (lower limit margin) that varies depending on the path distance L1. The lower limit margin is specified, for example, as a percentage of the target excavation volume WB. Furthermore, as shown in this figure, the lower limit margin is set to a larger value, for example, the shorter the path distance L1. In other words, the shorter the path distance L1, the smaller the value of the excavation volume lower limit WBmin.

In this embodiment, the wheel loader 100 excavates at the excavation position, then moves to the loading position and performs loading. Therefore, the path distance L1 is the distance from the excavation position to the loading position. In such an environment, if the path distance L1 is short, even if the amount of excavation is insufficient, it is more efficient to continue traveling to the loading position and perform the next excavation rather than dumping the soil and excavating again, as this will allow for a larger amount of loading per hour.

The behavior management unit 211 calculates the excavation volume upper limit WBmax and the excavation volume lower limit WBmin using the excavation volume upper and lower limit data 510 each time the target excavation volume WB is updated. Note that instead of the excavation volume upper and lower limit data 510, an upper limit margin and a lower limit margin may be stored in the storage device 183.

When calculating the target excavation volume WB, the behavior management unit 211 also calculates the already loaded volume WA and the remaining loaded volume WR. A predetermined margin (loading volume margin) may also be set for the target loading volume WT used at this time. Figure 8(b) shows an example of the relationship between the loading volume margin set for the target loading volume WT and the route distance L1. This data is stored in advance in the storage device 183, etc. as loading volume lower limit data 520.

As shown in this diagram, a loading amount margin is set for the target loading amount WT, and this is set as the loading amount lower limit WTmin. The loading amount margin is stored in advance in the storage device 183, etc. When calculating the remaining loading amount WR, the behavior management unit 211 sets the remaining loading amount WR to 0 if the already loaded amount WA is less than the target loading amount WT but is equal to or greater than the loading amount lower limit WTmin. As a result, if the already loaded amount WA is equal to or greater than the loading amount lower limit WTmin, the target excavation amount becomes 0 and the work is determined to be complete.

Next, we will explain the flow of behavior management processing, mainly by the behavior management unit 211, of the autonomous driving control device 200 when a work instruction 230 is acquired. Figure 9 shows the processing flow of the behavior management processing in this embodiment. The current position is acquired from the positioning device 141 at predetermined time intervals. In the following processing, the autonomous driving control device 200 uses the most recent current position acquired at that time.

First, upon receiving a work instruction 230, the behavior management unit 211 first sets the initial target excavation volume WB and loading volume lower limit WTmin (step S1100). Here, the target loading volume 233 in the work instruction 230 is set as the initial remaining loading volume WR, and this is compared with the standard excavation volume WS, and the target excavation volume WB is determined using the above method. Furthermore, the target loading volume 233 is set as WT, and the loading volume lower limit WTmin is calculated using the loading volume margin.

Next, the behavior management unit 211 sets the excavation position to the target position (step S1101). Here, the excavation position is obtained from the work instruction 230 (excavation position 235).

The behavior management unit 211 then acquires the target route (step S1102). Here, the behavior management unit 211 transmits the target position to the route planning unit 212. The route planning unit 212 uses the map data 220 to generate the target route using the current position and the target position.

For example, suppose that work Ins01 in the work instruction 230 is being performed, and the position of the wheel loader 100 when this work instruction is received is p0. In this case, the current position is p0 in the map data 220. Furthermore, the excavation position Q1 is p8 in the map data 220. The target route 240 created in this case is as shown in Figure 7(b). In other words, the route planning unit 212 creates a route that advances sequentially between each point from p0 to p8.

The behavior management unit 211 then controls the wheel loader 100 to move to the excavation position (step S1103). The behavior management unit 211 sets the operation mode of the wheel loader 100 to traveling mode and transmits this to the behavior generation unit 213. The behavior management unit 211 also causes the path planning unit 212 to transmit the generated target path to the behavior generation unit 213. The behavior generation unit 213 generates and outputs various control signals to travel along the target path to the target position.

Once the wheel loader 100 has reached the excavation position, the behavior management unit 211 causes the wheel loader 100 to perform excavation (step S1104). In traveling mode, the behavior management unit 211 compares the current position with the target position each time it obtains it from the positioning device 141. If the current position matches the target position, it determines that the excavation position has been reached. The behavior management unit 211 then sets the operation mode to excavation mode and transmits this to the action generation unit 213. In response, the action generation unit 213 generates and outputs various control signals to perform excavation.

Once excavation is complete, the behavior management unit 211 acquires the actual excavation volume (step S1105). Here, the load information of the bucket 121 is acquired from the load acquisition device 142, and this is used as the actual excavation volume.

Next, the behavior management unit 211 proceeds to the loading process. Specifically, first, the loading position is set to the target position (step S1106). The loading position is obtained from the work instruction 230 (loading position 234).

The behavior management unit 211 then acquires the target route (step S1107). Here, the behavior management unit 211 transmits the target position to the route planning unit 212. The route planning unit 212 uses the map data 220 to generate the target route using the current position and the target position.

For example, when performing work Ins01 of work instruction 230, the current position is p8 in map data 220. Furthermore, loading position R1 is p6 in map data 220. In this case, the target route 240a created is as shown in Figure 7(c). In this case, the route planning unit 212 creates a route that moves backward from point p8 via point p7 to point p9, and then moves forward via point p7 to point p6.

Furthermore, when performing work Ins02 of work instruction 230, movement is made from digging position Q2 to loading position R2. In this case, the current position is p1 in map data 220, and the target position is p2 in the map data. The target route 240b created in this case is as shown in Figure 7(d). In this case, the route planning unit 212 creates a route that moves backward from point p1 via point p4 to point p5, and then moves forward via p4 and p3 to p2.

Next, the behavior management unit 211 calculates and sets the excavation volume upper limit WBmax and the excavation volume lower limit WBmin (step S1108). The behavior management unit 211 calculates the excavation volume upper limit WBmax based on the excavation volume upper and lower limit data 510 in accordance with the target excavation volume WB. The behavior management unit 211 also calculates the route distance L1 using the target route and map data 220. Then, the behavior management unit 211 calculates the excavation volume lower limit WBmin based on the excavation volume upper and lower limit data 510 in accordance with the target excavation volume WB and the route distance L1.

Note that the calculation of the upper excavation volume limit WBmax and the lower excavation volume limit WBmin is not limited to this timing. For example, they may be calculated between the setting of the target excavation volume WB and the determination of the adequacy of the excavation volume, as described below.

The behavior management unit 211 then determines whether the actual excavation amount is within the allowable excavation amount range (step S1109). The allowable excavation amount range is between the upper excavation amount limit WBmax and the lower excavation amount limit WBmin (less than the upper excavation amount limit and greater than or equal to the lower excavation amount limit).

If it is within the allowable range (S1109; Yes), the behavior management unit 211 controls the wheel loader 100 to move to the loading position (step S1121). Here, the behavior management unit 211 sets the operation mode of the wheel loader 100 to a traveling mode and transmits this to the behavior generation unit 213. The behavior management unit 211 also causes the path planning unit 212 to transmit the generated target path to the behavior generation unit 213. The behavior generation unit 213 generates and outputs various control signals to travel along the target path to the target position.

Once the wheel loader 100 has reached the loading position, the behavior management unit 211 causes the wheel loader 100 to begin loading (step S1122). Each time the behavior management unit 211 acquires the current position from the positioning device 141, it compares it with the target position, and if the current position matches the target position, it determines that the wheel loader 100 has arrived at the loading position. The behavior management unit 211 then sets the operation mode to loading mode and transmits this to the operation generation unit 213. In response, the operation generation unit 213 generates and outputs various control signals to perform loading.

Once loading is complete, the behavior management unit 211 updates the target excavation volume WB (step S1123). Here, the behavior management unit 211 adds the actual excavation volume acquired in step S1106 to the already loaded volume WA, updating the already loaded volume WA. Then, the remaining loading volume WR is calculated, and this is compared with the standard excavation volume WS using the method described above to calculate a new target excavation volume WB.

Then, the behavior management unit 211 determines whether the new target excavation volume WB is 0 (step S1124).

If the target excavation volume WB is not 0 (step S1124; No), further excavation and loading is required, so proceed to step S1101.

On the other hand, if the target excavation volume WB is 0 (step S1124; Yes), loading is determined to be complete and processing ends.

Next, in step S1109, if the excavation amount is outside the allowable excavation amount range (S1109; No), the behavior management unit 211 proceeds to the soil release process.

Specifically, the behavior management unit 211 first determines whether the excavation volume is insufficient (step S1131). Here, it determines whether the actual excavation volume is less than the excavation volume lower limit WBmin.

If the actual excavation volume is less than the excavation volume lower limit WBmin (S1131; Yes; insufficient excavation volume), the behavior management unit 211 notifies the user to excavate again (step S1132). Here, a message indicating that excavation will be performed again is generated and sent to the user interface 190 as notification information.

The behavior management unit 211 then causes the wheel loader 100 to perform the soil discharge process (step S1134) and proceeds to step S1101. During the soil discharge process, the behavior management unit 211 sets the operation mode to soil discharge mode and sends this to the action generation unit 213. In response, the action generation unit 213 generates and outputs various control signals to perform soil discharge.

The wheel loader 100 excavates with the tip of the bucket 121 raised, so when re-excavating, the bucket 121 must be lowered. At this time, the bucket 121 is temporarily moved backward to lower it so that it does not hit the object to be excavated. Therefore, when re-excavating, the process returns (moves) to a position where re-excavation is possible, and the process proceeds to step S1101, where the process of setting the excavation position to the target position is repeated again.

On the other hand, if the actual excavation volume is not less than the excavation volume lower limit WBmin (S1131; No), that is, if it is equal to or greater than the excavation volume upper limit WBmax (excavation volume is excessive), the process of step S1132 is not performed and the process proceeds to step S1133. This is because when the excavation volume is insufficient, there is a possibility that the excavation target itself is insufficient, whereas when the excavation volume is excessive, there is no need to worry about this. For this reason, the user is only warned when the excavation volume is insufficient. However, the user may also be notified to excavate again when the excavation volume is excessive.

As explained above, the control system 180 for the wheel loader 100 in this embodiment has an automatic driving control device 200 that controls the operation of the wheel loader 100, which has a bucket 121 as a work implement, and a load acquisition device 142 that measures the load of an object in the bucket 121. The automatic driving control device 200 has a behavior management unit 211 that sets a target position to which the wheel loader 100 will move, and the behavior management unit 211 determines the target position according to the load load acquired by the load acquisition device 142.

As a result, according to this embodiment, when automatically excavating an excavation target, transporting it to the target position, and loading it, the wheel loader 100 can be controlled to take appropriate action depending on the load (excavation volume) in the bucket 121.

For example, if the load is within a predetermined excavation tolerance range, the target position is set as the loading position, and if it is outside the tolerance range, the target position is set as the soil dumping position. This allows soil to be dumped and excavation to be carried out again if the amount of excavation is too much or too little.

In addition, in this embodiment, the value of the excavation volume lower limit WBmin, which determines the allowable excavation range, is changed according to the path distance L1, which is the distance between the excavation position and the loading position. Specifically, the shorter the path distance L1, the smaller the value of the excavation volume lower limit WBmin. As a result, according to this embodiment, the wheel loader 100 can be controlled to perform optimal operation according to the traveling distance.

<Modification 1>
In the above embodiment, the behavior management unit 211 controls the work so that soil is released and excavation is performed again at the excavation position specified in the work instruction 230 even if the actual excavation volume is less than the excavation volume lower limit WBmin, but this is not limited to this.

For example, if the actual excavation volume is less than the excavation volume lower limit WBmin, the behavior management unit 211 notifies the user. The user may receive this notification and change the excavation position as necessary. For example, this may occur if there are not enough excavation targets at the excavation position. In this case, in step S1101, the new excavation position set by the user is set as the target position.

<<Second Embodiment>>
Next, a second embodiment of the present invention will be described. In this embodiment, the excavation amount lower limit WBmin is changed depending on the number of times excavation is repeated due to an insufficient excavation amount. The following description of this embodiment will focus on the configuration that is different from the first embodiment.

The configuration of the wheel loader 100, the configuration of its control system 180, and the hardware configuration and functional blocks of the automatic driving control device 200 of this embodiment are the same as those of the first embodiment. However, the processing of the behavior management unit 211 is different.

In this embodiment, the behavior management unit 211 counts the number of times re-excavation is required due to an insufficient excavation amount (number of re-excavations). Furthermore, the greater the number of re-excavations, the smaller the excavation amount lower limit WBmin is set. This is because repeated re-excavations due to an insufficient excavation amount may be due to a decrease in the number of objects that can be excavated. In this way, by correcting the excavation amount lower limit WBmin, it is possible to avoid repeated, unnecessary excavation even when the number of excavation objects decreases and it becomes difficult to ensure the required excavation amount.

Specifically, when calculating the excavation volume lower limit, the behavior management unit 211 first determines the excavation volume lower limit WBmin as a candidate lower limit according to the path distance L1, as in the first embodiment. Then, according to predetermined rules, the candidate lower limit is processed so that the greater the number of re-excavations, the smaller the value becomes, and a corrected excavation volume lower limit WBmin1 is calculated. For example, the candidate lower limit is multiplied by a coefficient corresponding to the number of re-excavations to determine the corrected excavation volume lower limit WBmin1. The coefficient is determined so that the greater the number of re-excavations, the smaller the corrected excavation volume lower limit WBmin1 becomes.

Figure 10 shows an example of the relationship between the number of re-excavations and the corrected excavation volume lower limit WBmin1. This data is stored in advance in the storage device 183, etc., as lower limit correction data 511.

The flow of behavior management processing by the autonomous driving control device 200 in this embodiment will be described. Figure 11 shows the processing flow of behavior management processing in this embodiment. It is assumed that the current position is acquired from the positioning device 141 at predetermined time intervals. In the following processing, the autonomous driving control device 200 uses the most recent current position acquired at that time. The following explanation will focus on the differences from the flow of behavior management processing in the first embodiment.

First, upon receiving a work instruction, the behavior management unit 211 sets the initial target excavation volume WB and the loading volume lower limit WTmin, and initializes a counter n (n is an integer greater than or equal to 1) that counts the number of re-excavations (step S2100). Note that here, counter n is set to 1.

Next, the behavior management unit 211 sets the excavation position as the target position (step S1101). Then, the behavior management unit 211 acquires the target route (step S1102).

The behavior management unit 211 then controls the wheel loader 100 to move to the excavation position (step S1103). Once moved to the excavation position, the behavior management unit 211 causes the wheel loader 100 to excavate (step S1104). Once excavation is complete, the behavior management unit 211 acquires the actual excavation volume (step S1105).

Next, the behavior management unit 211 proceeds to loading processing. Specifically, first, the loading position is set to the target position (step S1106). Then, the behavior management unit 211 acquires the target route (step S1107). Then, the behavior management unit 211 calculates and sets the upper excavation volume limit WBmax and the lower excavation volume limit WBmin (step S1108).

Next, in this embodiment, the behavior management unit 211 corrects the excavation volume lower limit WBmin according to the number of re-excavations (step S2103). Here, the correction is made in accordance with the count lower limit correspondence data, which defines that the greater the number of re-excavations, the smaller the value of the excavation volume lower limit WBmin. Then, the corrected excavation volume lower limit WBmin1 is obtained. The behavior management unit 211 then determines whether the actual excavation volume is within the allowable range of excavation volumes (step S1109). The allowable range of excavation volumes is between the excavation volume upper limit WBmax and the corrected excavation volume lower limit WBmin1.

If it is within the allowable range (S1109; Yes), the behavior management unit 211 controls the wheel loader 100 to move to the loading position (step S1121). Once it has moved to the loading position, the behavior management unit 211 causes the wheel loader 100 to load (step S1122). Once loading is complete, the behavior management unit 211 updates the target excavation volume (step S1123). Thereafter, the behavior management unit 211 determines whether the target excavation volume is 0 (step S1124).

If the target excavation volume is not 0 (step S1124; No), further excavation and loading is required, so proceed to step S1101. On the other hand, if the target excavation volume is 0 (step S1124; Yes), loading is determined to be complete, and processing ends.

Next, in step S1109, if the excavation amount is outside the allowable excavation amount range (S1109; No), the behavior management unit 211 proceeds to the soil release process.

Specifically, the behavior management unit 211 first determines whether the excavation amount is insufficient (step S1131). If the actual excavation amount is less than the corrected excavation amount lower limit WBmin1 (S1131; Yes; excavation amount is insufficient), the behavior management unit 211 first increments the number of re-excavations. Specifically, it increments the counter by 1 (step S2131). The behavior management unit 211 then notifies the user of the re-excavation (step S1132). The behavior management unit 211 then causes the wheel loader 100 to perform soil discharge processing (step S1133) and proceeds to step S1101.

On the other hand, if the actual excavation volume is not less than the corrected excavation volume lower limit WBmin1 (S1131; No), that is, if it is greater than or equal to the excavation volume upper limit WBmax (excessive excavation volume), steps S2131 and S1132 are not performed, and the process proceeds to step S1133.

This is because when the excavation volume is insufficient, there is a possibility that the excavation target itself is insufficient, so a notification is sent to alert the user. On the other hand, when the excavation volume is excessive, there is no need to worry about this. However, even when the excavation volume is excessive, the user may be notified to excavate again.

As explained above, in the construction machine control system 180 of this embodiment, if the live load (excavation volume) is less than the excavation volume lower limit WBmin, the behavior management unit 211 repeatedly controls the construction machine to release the excavated object and excavate again, and the more times this is repeated, the smaller the value of the excavation volume lower limit is set.

For this reason, according to this embodiment, even when the number of excavation objects themselves is low and there is a high possibility that the excavation volume is insufficient, the wheel loader 100 can be controlled to take appropriate action.

<Modification 2>
In this embodiment, as in the first embodiment, when re-excavation is required due to an insufficient excavation amount, the user may be configured to be able to change the excavation position.

<Modification 3>
In this embodiment, as in the first embodiment, the shorter the path distance L1, the smaller the excavation amount lower limit WBmin is set, and the greater the number of re-excavations, the larger the excavation amount lower limit WBmin is set, but this is not limiting. For example, the excavation amount lower limit WBmin may change depending only on the number of re-excavations, regardless of the path distance L1.

<Other Modifications>
In addition, in the above-described embodiments, the lower limit margin is described as decreasing continuously and monotonically according to the path distance L1, but the change in the lower limit margin is not limited to this. For example, the lower limit margin may decrease stepwise every predetermined distance. The change in the lower limit margin according to the number of re-excavation attempts may also be stepwise.

Furthermore, although the upper and lower limit margins are defined as percentages of the target excavation volume WB, they are not limited to this. They may also be defined as absolute amounts.

Furthermore, in each of the above embodiments, the actual excavation amount obtained immediately after excavation is added directly to the loading amount, but this is not limited to this. For example, immediately before loading, live load information may be obtained again from the load acquisition device 142, and this value may be added to calculate the already loaded amount WA.

In addition, in the above embodiments, the case where the soil release position is set to the same position as the excavation position has been described as an example, but this is not limited to this. The soil release position may be set to a position different from the excavation position. In this case, if the excavation volume is too much or too little and soil needs to be released, the soil release position is set to the target position, and the robot travels to the release position and releases the soil. Then, after releasing the soil, the excavation position is set to the target position again and the robot returns to the excavation position.

In addition, in each of the above embodiments, the work instructions 230 are described as being input by the user via the user interface 190, but the acquisition of these instructions is not limited to this. For example, the automatic driving control device 200 may be provided with a receiving unit, and the instructions may be received directly via the receiving unit. The receiving unit is realized by the communication I/F 185. In this case, the work instructions are created by a computer (management device) installed in a management center or the like, and transmitted to the automatic driving control device 200.

Although the embodiments of the present invention have been described in detail above, the present invention is not limited to the above-described embodiments and includes various modifications. For example, while the above-described embodiments apply 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 other than wheel loaders, such as hydraulic excavators. Furthermore, the above-described embodiments have been described in detail to clearly explain the present invention, and the present invention is not necessarily limited to those that include all of the configurations described.

The present invention is not limited to the above-described embodiment, and various modifications are possible without departing from the spirit of the present invention. All technical matters included in the technical concept set forth in the claims are within the scope of the present invention. The above-described embodiment shows a preferred example, but a person skilled in the art will be able to realize various alternatives, modifications, variations, or improvements based on the contents disclosed in this specification, and these will fall within the technical scope set forth in the accompanying claims.

100: Work machine (wheel loader), 110: Body, 111: Engine, 112: Steering cylinder, 113: Driving force transmission device, 114: Hydraulic pump, 115: Control valve, 120: Work machine, 121: Bucket, 122: Lift arm, 123: Bell crank, 124: Bucket link, 125: Lift cylinder, 126: Bucket cylinder, 131: Tire, 131FL: Front left tire, 131FR: Front right tire, 131RL: Rear left Tire, 131RR: rear right tire, 132C: center joint, 133F: brake, 133R: brake, 134F: front differential, 134R: rear differential, 141: positioning device, 142: load acquisition device, 150: engine control device, 160: hydraulic control device, 170: driving control device, 180: control system, 181: CPU, 182: memory, 183: storage device, 184: input/output I/F, 185: communication I/F, 190: user interface,
200: Automatic driving control device, 211: Behavior management unit, 212: Route planning unit, 213: Action generation unit, 220: Map data, 221: Point, 222: Coordinates, 223: Attribute, 224: Line segment, 225: End point, 226: End point, 230: Work instruction, 231: ID, 232: Type, 233: Target loading amount, 234: Loading position, 235: Excavation position, 236: Discharge position, 240: Target route, 240a: Target route, 240b: Target route, 241: Passing point, 242: FNR,
300: working area, 310: excavation target, 320: loading target,
510: upper and lower limit data of excavation volume, 511: lower limit correction data, 520: lower limit data of loading volume,
WA: Amount already loaded, WB: Target excavation amount, WBmax: Upper limit of excavation amount, WBmin: Lower limit of excavation amount, WBmin1: Lower limit of excavation amount after correction, WR: Remaining loading amount, WS: Standard excavation amount, WT: Target loading amount, WTmin: Lower limit of loading amount

Claims (10)

an automatic driving control device that controls the operation of a work machine having a work implement;
a load acquisition device that measures the load of an object in the work tool;
a positioning device that acquires the current position of the work machine,
The automatic driving control device includes:
a behavior management unit that sets a target position to which the work machine is to be moved;
a route planning unit that generates a target route, which is a travel route between the current position acquired by the positioning device and the target position set by the behavior management unit;
a movement generating unit that generates a control signal for operating the work machine in accordance with the target path generated by the path planning unit;
Equipped with
the behavior management unit determines the target position in accordance with the live load acquired by the load acquisition device;
a control system for a work machine, wherein the operation generating unit generates a control signal for causing the work machine to travel to the target position and loading an object in the work implement onto a loading target; 2. A work machine control system according to claim 1,
The behavior management unit calculates a target live load based on a predetermined target live load for a loading object and the capacity of the work tool, and if the live load is less than an upper limit value and equal to or greater than a lower limit value predetermined for the target live load, sets the loading position where the loading object is located as the target position. 2. A work machine control system according to claim 1,
The behavior management unit calculates a target live load based on a predetermined target live load for a loading object and a capacity of the work tool, and when the live load is equal to or greater than a predetermined upper limit value for the target live load, sets a predetermined soil release position as the target position;
a control system for a work machine, wherein the operation generating unit generates a control signal for causing the work machine to travel to the target position and releasing an object in the work tool at the target position. 2. A work machine control system according to claim 1,
The behavior management unit calculates a target live load based on a predetermined target live load for a loading object and a capacity of the work tool, and when the live load is less than a predetermined lower limit value as the target live load, sets a predetermined soil release position as the target position;
a control system for a work machine, wherein the operation generating unit generates a control signal for causing the work machine to travel to the target position and releasing an object in the work tool at the target position. 5. A work machine control system according to claim 4,
a behavior management unit that, when the load of an object in the work tool excavated at a predetermined first excavation position is less than the lower limit value and an operation of releasing the object in the work tool at the target position is executed, sets a second excavation position different from the first excavation position as the target position. 5. A work machine control system according to claim 4,
the operation generating unit generates a travel control signal and a hydraulic control signal for loading an object into the work tool at a predetermined excavation position;
The behavior management unit determines the lower limit value in accordance with a route distance that is a distance from the excavation position to a loading position where the loading object is located. 7. A work machine control system according to claim 6,
The behavior management unit sets the lower limit value to a smaller value as the path distance becomes shorter. A work machine control system according to claim 4 or 6,
The behavior management unit repeatedly controls the work machine to release the excavated object and excavate it again when the live load is less than the lower limit, and sets the lower limit to a smaller value as the number of repetitions increases. A control system for a work machine according to any one of claims 2 to 8,
The behavior management unit sets the target live load to the smaller of the target live load minus the load after loading onto the loading target from the target live load and the capacity of the work tool. A work machine equipped with the work machine control system according to any one of claims 1 to 9.