Work machine control device

Abstract

To provide a control device of a work machine that allows the work machine to perform a stable excavation work while avoiding contact between the work machine and obstacles.SOLUTION: A behavior management section 211 determines whether there is a possibility of contact between an obstacle and a work machine based on an angular error of the work machine at a run-up start position, a lateral distance to a laterally distant obstacle, and a distance from the work machine to an excavation object. When the behavior management section determines that there is a possibility of contact, a route planning section 212 generates a corrected route Rc, the behavior management section outputs a travel command TC, and a motion generation section 213 outputs a control signal based on the travel command and the corrected route and causes the work machine to perform an automatic travel along the corrected route. When the behavior management section determines that there is no possibility of contact, the behavior management section outputs an excavation command EC, and the motion generation section outputs a control signal based on the excavation command and a straight route Rs to cause the work machine to perform an automatic excavation including an automatic travel along the straight route.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a control device for a work machine. [Background technology]

[0002] There have been known work control devices for loading and transporting vehicles. For example, Patent Document 1 listed below discloses a work control device for a loading and transporting vehicle that performs one cycle of loading and transporting work, in which the vehicle loads a load at a loading position in a loading area, returns to a dumping area via a turning point, unloads the load at the dumping area, and then moves from the dumping area to the loading area via a turning point again (claim 1, paragraph 0008, etc.).

[0003] This conventional work control device for a loading and transporting vehicle comprises input means, calculation means, and control means. The input means inputs teaching data for the vehicle positions and vehicle attitude angles at the loading site, turning point, and dumping site. The calculation means calculates the positions of each point on a planned travel route connecting the loading site, turning point, and dumping site based on the teaching data input by the input means. The control means controls the loading and transporting vehicle so that the loading and transporting vehicle moves along each point on the planned travel route calculated by the calculation means and performs loading and transporting work.

[0004] According to this conventional work control device for loading and transporting vehicles, the planned travel route can be changed simply by re-entering the teaching data without actually re-laying the guide wires on site, making it easy to deal with changes in the layout of the travel route and dramatically improving flexibility in terms of layout changes (Patent Document 1, paragraph 0010). [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 10-212035 Summary of the Invention [Problem to be solved by the invention]

[0006] In a work site where a work machine such as the above-mentioned loading and transporting vehicle works, there may be obstacles that the work machine must avoid, such as a stockyard partitioned by partitions. In such a case, with the above-mentioned conventional loading and transporting vehicle control device, there is a risk that the loading and transporting vehicle will come into contact with the obstacle due to errors in the direction of the loading and transporting vehicle or the influence of unevenness of the ground surface.

[0007] The present invention provides a control device for a work machine that is capable of causing the work machine to perform stable excavation work while avoiding contact between the work machine and an obstacle. [Means for solving the problem]

[0008] One aspect of the present invention is a control device for a work machine that causes a work machine to automatically excavate an excavation target, the control device comprising: a behavior management unit that acquires a run-up start position where the work machine starts moving straight towards the excavation target when starting automatic excavation, and outputs operation commands including an excavation command for the work machine; a path planning unit that generates a target path including a straight path based on the straight-line direction of the work machine that has reached the run-up start position; and an operation generation unit that outputs control signals based on the operation commands and the target path to cause the work machine to perform automatic excavation or automatic traveling, the behavior management unit deriving an angular error in the straight-line direction based on a run-up direction that faces the excavation target at the run-up start position, a lateral distance from the work machine to an obstacle located laterally away from the work machine and perpendicular to the run-up direction, and a path planning unit that generates a target path including a straight path based on the straight-line direction of the work machine when it has reached the run-up start position, the operation generation unit deriving an angular error in the straight-line direction based on a run-up direction that faces the excavation target at the run-up start position, a lateral distance from the work machine to an obstacle located laterally away from the work machine and perpendicular to the run-up direction, and a path planning unit that generates a target path including a straight path based on the operation commands and the target path. and a distance in the approach direction from the work machine to the excavation target object, and if the behavior management unit determines that there is a possibility of contact, the path planning unit generates a corrected path that corrects the angle error as the target path, the behavior management unit outputs a traveling command as the operation command, and the operation generation unit outputs a control signal based on the traveling command and the corrected path to cause the work machine to perform automatic traveling along the corrected path, and if the behavior management unit determines that there is no possibility of contact, the behavior management unit outputs an excavation command as the operation command, and the operation generation unit outputs a control signal based on the excavation command and the straight path to cause the work machine to perform automatic excavation including automatic traveling along the straight path. [Effects of the Invention]

[0009] According to the present invention, it is possible to provide a control device for a work machine that is capable of causing the work machine to perform stable excavation work while avoiding contact between the work machine and an obstacle. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a perspective view of a work machine illustrating an embodiment of a control device for a work machine according to the present invention; [Figure 2] FIG. 2 is a block diagram showing the configuration of the work machine of FIG. 1. [Figure 3] FIG. 3 is a functional block diagram illustrating an automatic driving control device of the control device of the work machine of FIG. 2. [Figure 4] FIG. 4 is a flow diagram illustrating processing by the automatic driving control device of FIG. 3. [Figure 5] 5 is a plan view of the work machine and the excavation target, illustrating each process in the flowchart of FIG. 4. [Figure 6] 6 is a graph showing the relationship between the angle error Δθ of the work machine of FIG. 5 and the minimum run-up distance Dm. [Figure 7] FIG. 5 is a plan view illustrating the process of generating the corrected path in FIG. 4. [Figure 8] 8 is a graph showing the relationship between the Pp-Pc distance and the spacing Dw and length Dl of the partition walls in FIG. 7. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, an embodiment of a control device for a work machine according to the present invention will be described with reference to the drawings.

[0012] Fig. 1 is a perspective view of a work machine 100 showing one embodiment of a control device for a work machine according to the present invention. Fig. 2 is a block diagram showing the configuration of the work machine 100 of Fig. 1.

[0013] The construction machine control device 200 of this embodiment is mounted, for example, on the construction machine 100 that is the control target, and causes the construction machine 100 to automatically excavate an excavation target. The construction machine 100 is, for example, a work vehicle, and more specifically, a wheel loader. Note that the construction machine control device 200 is not limited to wheel loaders, and can control any construction machine that excavates an excavation target.

[0014] 1, the work machine 100 includes a vehicle body 110, a work implement 120, and a steering mechanism 130. The work machine 100 also includes an engine 140, a hydraulic pump 150, a power transmission mechanism 160, a control valve 170, a sensor 180, a user interface 190, and a work machine control device 200, for example, as shown in FIG.

[0015] 2, the vehicle body 110 has an articulated configuration in which a front vehicle body 111 and a rear vehicle body 112 are connected via a center joint 113. The front vehicle body 111 has, for example, left and right front wheels 114, 114, and the rear vehicle body 112 has, for example, left and right rear wheels 115, 115.

[0016] The front vehicle body 111 is equipped with a front differential 116 that drives left and right front wheels 114, 114, and the rear vehicle body 112 is equipped with a rear differential 117 that drives left and right rear wheels 115, 115. The front vehicle body 111 is equipped with a front brake 118 that brakes the left and right front wheels 114, 114, and the rear vehicle body 112 is equipped with a rear brake 119 that brakes the left and right rear wheels 115, 115.

[0017] The working device 120 includes, for example, a pair of lift arms 121, a pair of lift cylinders 122, a bucket 123, a bell crank 124, a bucket link 125, and a bucket cylinder 126. The base ends of the pair of lift arms 121 are rotatably attached to the upper rear end of the front body 111, and the tip ends of the pair of lift arms 121 are rotatably connected to the outer bottom of the bucket 123.

[0018] Each of the pair of lift cylinders 122 includes, for example, a cylinder tube and a piston rod. The base end of the cylinder tube of each lift cylinder 122 is rotatably attached to the rear of the front vehicle body 111 below the base end of each of the pair of lift arms 121. The tip end of the piston rod of each lift cylinder 122 is rotatably connected to the lower part of the middle part of each lift arm 121 extending in the fore-and-aft direction of the vehicle body 110.

[0019] With this configuration, when the piston rods of the pair of lift cylinders 122 extend, the lift arm 121 rotates upward around the rotation shaft at the base end, lifting the bucket 123. When the piston rods of the pair of lift cylinders 122 retract, the lift arm 121 rotates downward around the rotation shaft at the base end, lowering the bucket 123.

[0020] The bucket 123 is a work implement rotatably attached to the tip of the lift arm 121. The bucket 123 can excavate and scoop up an object to be excavated, for example, by lowering the tip of the lift arm 121 to near the ground surface and moving the work machine 100 forward with the edge of the bucket 123 facing forward.

[0021] The center of the bell crank 124 is rotatably supported by a connecting portion that connects the pair of lift arms 121. One end of the bell crank 124 is connected to the piston rod of the bucket cylinder 126, and the other end of the bell crank 124 is rotatably connected to one end of a bucket link 125. As shown in FIG. 1 , with the bucket 123 lowered and facing forward, the other end of the bucket link 125 is rotatably attached to the outer bottom of the bucket 123 at a position above the connecting position of the tips of the pair of lift arms 121.

[0022] The bucket cylinder 126 is, for example, a hydraulic cylinder equipped with a cylinder tube and a piston rod. The base end of the cylinder tube of the bucket cylinder 126 is rotatably attached between the base ends of the pair of lift arms 121 at the upper rear end of the front body 111. The tip of the piston rod of the bucket cylinder 126 is rotatably attached to one end of the bell crank 124.

[0023] With this configuration, when the piston rod of the bucket cylinder 126 extends, the bell crank 124 rotates so that the other end opposite to the end to which the tip of the piston rod is connected moves away from the bucket 123. Then, via the bucket link 125 that connects the other end of the bell crank 124 to the bottom of the bucket 123, the bucket 123 rotates upward about the rotation axis at the tip of the pair of lift arms 121.

[0024] Furthermore, when the piston rod of the bucket cylinder 126 contracts, the bell crank 124 rotates so that the other end opposite to the end to which the tip of the piston rod is connected approaches the bucket 123. This causes the bucket 123 to rotate downward about the rotation axis at the tip of the pair of lift arms 121 via the bucket link 125 that is connected to the other end of the bell crank 124 and the bottom of the bucket 123.

[0025] 2, the steering mechanism 130 includes a pair of steering cylinders 131 which are hydraulic cylinders. The steering mechanism 130 bends the front body 111 relative to the rear body 112 around the center joint 113 using the pair of steering cylinders 131, creating an angle difference between the front body 111 and the rear body 112, thereby turning the work machine 100.

[0026] The engine 140 is, for example, an internal combustion engine mounted on the rear body 112. A drive shaft of the engine 140 is connected, for example, to a hydraulic pump 150 and a power transmission mechanism 160. The engine 140 rotates the drive shaft to drive the hydraulic pump 150. The engine 140 also transmits power to a front differential 116 and a rear differential 117 via the power transmission mechanism 160 to drive the left and right front wheels 114, 114 and the left and right rear wheels 115, 115, causing the work machine 100 to travel.

[0027] The hydraulic pump 150 is driven by the engine 140 and supplies hydraulic oil to the control valve 170. The control valve 170 distributes the hydraulic oil supplied from the hydraulic pump 150 to each section based on a hydraulic control signal input from a hydraulic control device 220 that constitutes a work machine control device 200, which will be described later. Specifically, the control valve 170 distributes the hydraulic oil to the front brake 118, the rear brake 119, the pair of lift cylinders 122, the bucket cylinder 126, and the pair of steering cylinders 131.

[0028] As a result, the front brake 118 and the rear brake 119 are actuated by the hydraulic pressure of the hydraulic oil supplied from the control valve 170 to brake the left and right front wheels 114, 114 and the left and right rear wheels 115, 115, thereby slowing down or stopping the work machine 100. In addition, the piston rods of the pair of lift cylinders 122 extend and retract due to the hydraulic pressure of the hydraulic oil supplied from the control valve 170, causing the pair of lift arms 121 to rotate up and down, and raising and lowering the bucket 123.

[0029] The bucket cylinder 126 has a piston rod that extends and retracts due to the hydraulic pressure of the hydraulic oil supplied from the control valve 170, causing the bucket 123 to rotate up and down via the bell crank 124 and bucket link 125. The pair of steering cylinders 131 also have piston rods that extend and retract due to the hydraulic pressure of the hydraulic oil supplied from the control valve 170, causing an angular difference between the front body 111 and the rear body 112 about the center joint 113, causing the work machine 100 to turn.

[0030] The sensor 180 includes, for example, a position sensor 181 and an external sensor 182. Although not shown, the sensor 180 may include, for example, an angle sensor that detects the rotation angle of the lift arm 121 relative to the front body 111 or the rotation angle of the bell crank 124. The sensor 180 may also include, for example, a pressure sensor that detects the pressure of hydraulic oil housed in the cylinder tubes of the lift cylinder 122, the bucket cylinder 126, and the steering cylinder 131.

[0031] The position sensor 181 can be configured, for example, by a Global Navigation Satellite System (GNSS) antenna and receiver mounted on the rear body 112. Alternatively, the position sensor 181 may be configured by a Simultaneous Localization and Mapping (SLAM) system that uses a camera and LIDAR (laser radar). The position sensor 181 is connected to be able to communicate information with an automatic driving control device 210 that constitutes the work machine control device 200, which will be described later, and detects the position and direction of the work machine 100 and outputs the detection results to the automatic driving control device 210.

[0032] The external sensor 182 includes, for example, a camera, LIDAR, millimeter wave radar, ultrasonic sensor, etc., and detects objects around the work machine 100. If the position sensor 181 is configured using a SLAM system, the camera or LIDAR that configures the position sensor 181 can also be used as the external sensor 182. The external sensor 182 is connected to be able to communicate information with an automatic driving control device 210 that configures the work machine control device 200, which will be described later, and detects objects around the work machine 100 and outputs the detection results DR to the automatic driving control device 210.

[0033] The user interface 190 is, for example, a personal computer (PC), a tablet terminal, or a mobile information terminal such as a smartphone. The user interface 190 is connected, for example, via a wireless communication line, to an automatic driving control device 210 of the work machine control device 200, which will be described later, so that information can be communicated therewith. The user interface 190, for example, transmits information input by the user to the automatic driving control device 210, and notifies the user of information received from the automatic driving control device 210 by image or sound.

[0034] The work machine control device 200 is configured, for example, by one or more microcontrollers equipped with a central processing unit (CPU), memory, a timer, and input / output units, and causes the work machine 100 to automatically excavate an excavation target. The work machine control device 200 is equipped, for example, with an automatic driving control device 210, a hydraulic control device 220, an engine control device 230, and a travel control device 240. Each device in the work machine control device 200 may be configured as a separate device, or two or more devices may be configured as a single device.

[0035] The automatic driving control device 210, for example, receives work instructions from the user via the user interface 190, and receives the position and direction of the work machine 100 from the position sensor 181. The automatic driving control device 210 may also receive detection results of the surroundings of the work machine 100 from the external sensor 182. Based on the input information, the automatic driving control device 210 generates a hydraulic control signal, an engine control signal, and a travel control signal, and outputs them to the hydraulic control device 220, the engine control device 230, and the travel control device 240, respectively.

[0036] The hydraulic control device 220 controls the opening of the multiple valves that make up the control valve 170 based on the hydraulic control signal input from the automatic driving control device 210. This controls the flow rate of hydraulic oil distributed to the front brake 118, rear brake 119, lift cylinder 122, bucket cylinder 126, and steering cylinder 131 based on the hydraulic control signal.

[0037] The engine control device 230 controls the rotation speed of the engine 140 based on the engine control signal input from the automatic driving control device 210. The driving control device 240 controls the gear ratio and rotation direction of the power transmission mechanism 160 based on the driving control signal input from the automatic driving control device 210.

[0038] Fig. 3 is a functional block diagram illustrating the automatic driving control device 210 that constitutes the work machine control device 200 of Fig. 2. The automatic driving control device 210 includes, for example, a behavior management unit 211, a path planning unit 212, and an action generation unit 213.

[0039] Each of these units of the automatic driving control device 210 represents a function of the automatic driving control device 210 that is realized, for example, by a CPU constituting the automatic driving control device 210 executing a program stored in memory. Note that each unit of the automatic driving control device 210 shown in Fig. 3 can also be configured by a separate microcontroller or firmware. Processing by the automatic driving control device 210 will be described below with reference to Figs. 4 to 8.

[0040] Figure 4 is a flow diagram illustrating the processing by the automatic driving control device 210 of Figure 3. Figure 5 is a plan view of the work machine 100 and the excavation target E, illustrating each process in the flow diagram of Figure 4. When, for example, a user inputs a work instruction to the user interface 190 and the work instruction OI is input from the user interface 190 to the behavior management unit 211, the automatic driving control device 210 starts the processing flow shown in Figure 4 and executes a route plan to the run-up start position P0 in process S1.

[0041] In this process S1, the behavior management unit 211 acquires the run-up start position P0 from which the work machine 100 starts moving straight toward the excavation target E when it starts automatic excavation, as shown in Fig. 5. This run-up start position P0 is included in the work instruction OI input to the behavior management unit 211 from the user interface 190, for example. The behavior management unit 211 outputs the acquired run-up start position P0 to the path planning unit 212.

[0042] The path planning unit 212 calculates a target path Rt for moving the work machine 100 from its current position to the run-up start position P0, based on the run-up start position P0 input from the behavior management unit 211 and the current position Pp and direction Ap of the work machine 100 acquired from the position sensor 181. The path planning unit 212 calculates the target path Rt, for example, so that at the run-up start position P0, the work machine 100 faces the excavation target E directly and the steering state of the work machine 100 is neutral, i.e., so that the excavation target E, the front vehicle body 111, and the rear vehicle body 112 are aligned in a straight line. The path planning unit 212 outputs the calculated target path Rt to the behavior management unit 211 and the action generation unit 213.

[0043] Here, the current direction Ap of the work machine 100 is, for example, the longitudinal direction of the work machine 100, which is perpendicular to the direction of the baseline connecting the two GNSS antennas that make up the position sensor 181 mounted on the vehicle body 110 and the height direction of the work machine 100. Furthermore, the path planning unit 212 may calculate the target path Rt, for example, based on the angle difference between the front body 111 and the rear body 112 about the center joint 113, in addition to the current position Pp and direction Ap of the work machine 100.

[0044] Next, in process S2, the automatic driving control device 210 executes automatic traveling of the work machine 100. In this process S2, the behavior management unit 211 outputs an operation command MC for the work machine 100 to the operation generation unit 213. More specifically, the behavior management unit 211 outputs to the operation generation unit 213 an operation command MC including a traveling command TC for transitioning the work machine 100 to a travel mode and traveling along the target route Rt.

[0045] The action generation unit 213 outputs a hydraulic control signal Sh, an engine control signal Se, and a travel control signal St to the hydraulic control device 220, the engine control device 230, and the travel control device 240, respectively, based on the action command MC input from the behavior management unit 211. As a result, the engine control device 230 controls the rotation speed of the engine 140, power is transmitted to the front differential 116 and the rear differential 117 via the power transmission mechanism 160, the left and right front wheels 114, 114 and the left and right rear wheels 115, 115 are driven, and the work machine 100 travels.

[0046] Furthermore, the rotation of the drive shaft of the engine 140 drives the hydraulic pump 150, which supplies hydraulic oil to the control valve 170. Furthermore, the control valve 170 is controlled by the hydraulic control device 220, which operates the front brake 118 and rear brake 119 as appropriate and extends and contracts the pair of steering cylinders 131 as appropriate. This controls the speed of the work machine 100, causing the work machine 100 to travel straight or turn while following the target route Rt.

[0047] Next, in process S3, the automatic driving control device 210 determines whether the work machine 100 has reached the run-up start position P0. In this process S3, the behavior management unit 211 compares the current position Pp of the work machine 100 acquired from the position sensor 181 with the run-up start position P0, which is the end point of the target route Rt.

[0048] If the behavior management unit 211 determines in process S3 that the current position Pp of the work machine 100 does not match the run-up start position P0 (NO), the automatic traveling of the work machine 100 continues, and process S3 is repeated at a predetermined cycle. On the other hand, if the behavior management unit 211 determines in process S3 that the current position Pp of the work machine 100 matches the run-up start position P0 (YES), the automatic driving control device 210 executes process S4 to acquire the run-up distance De.

[0049] In this process S4, the behavior management unit 211 acquires the run-up distance De from the current position Pp of the work machine 100, which has reached the run-up start position P0, to the excavation position Pe at which the work machine 100 excavates the excavation target E. This run-up distance De can be acquired, for example, based on the distance from the work machine 100 to the excavation target E, which is input to the behavior management unit 211 from the external sensor 182. The behavior management unit 211 may also acquire the run-up distance De based on the current position Pp of the work machine 100 and position information of the excavation target E that has been stored in advance in the memory of the work machine control device 200.

[0050] Next, the automatic driving control device 210 executes process S5 to determine whether the run-up distance De from the run-up start position P0, which is the current position Pp of the work machine 100, to the excavation position Pe is equal to or greater than the minimum run-up distance Dm. In process S5, the behavior management unit 211, for example, first obtains the minimum run-up distance Dm. The minimum run-up distance Dm is, for example, the minimum distance required to bring the steering state of the work machine 100 to a neutral state in which the front body 111 and the rear body 112 are aligned, and to move the work machine 100 in a straight line and reach a predetermined speed.

[0051] More specifically, to calculate the minimum run-up distance Dm, the behavior management unit 211 first obtains the angular error Δθ of the current straight-ahead direction As of the work machine 100, based on the run-up direction Af facing the excavation target E at the run-up start position P0, as shown in Fig. 5. This angular error Δθ can be caused by, for example, an error in the direction when the work machine 100 travels automatically in process S2 described above, or by the influence of unevenness of the ground surface on which the work machine 100 is traveling.

[0052] Next, the behavior management unit 211 calculates the minimum run-up distance Dm as the distance required for the work machine 100 to travel from the run-up start position P0, which is the current position Pp, towards the excavation target E, while reducing the angular error Δθ to zero and reaching a predetermined speed. As shown in Fig. 6, the minimum run-up distance Dm increases as the angular error Δθ increases. This is because, from the standpoint of the mechanical characteristics and running stability of the work machine 100, the steering speed that causes an angle difference between the front body 111 and the rear body 112 is limited, and a predetermined distance is required to make the work machine 100 reach a predetermined speed.

[0053] In this process S5, if the behavior management unit 211 determines that the run-up distance De from the run-up start position P0 to the excavation position Pe is shorter than the minimum run-up distance Dm calculated as described above (NO), the automatic driving control device 210 executes process S10 to generate a corrected route, which will be described later. On the other hand, if the behavior management unit 211 determines that the run-up distance De from the run-up start position P0 to the excavation position Pe is equal to or greater than the minimum run-up distance Dm calculated as described above (YES), the automatic driving control device 210 executes the next process S6.

[0054] In process S6, the automatic driving control device 210 determines whether or not there is an obstacle in the lateral direction Ac of the work machine 100. In this process S6, the behavior management unit 211 determines whether or not there is an obstacle away from the work machine 100 in the lateral direction Ac perpendicular to the run-up direction Af, for example, based on the detection results of the external sensor 182. The behavior management unit 211 may also determine whether or not there is an obstacle away from the work machine 100 in the lateral direction Ac based on map information recorded in advance in the memory of the automatic driving control device 210 and the current position Pp of the work machine 100.

[0055] Here, an example of an obstacle present in the lateral direction Ac of the work machine 100 is a stockyard partition wall W that separates stockpiles of different types of excavation targets E, as shown in Fig. 5. The stockyard partition walls W extend, for example, along the approach direction Af on both sides of the lateral direction Ac of the work machine 100 to both sides of the excavation targets E.

[0056] In this process S6, if the behavior management unit 211 determines that there is no obstacle in the lateral direction Ac (NO), the automatic driving control device 210 executes automatic excavation in process S12, which will be described later. On the other hand, in this process S6, if the behavior management unit 211 determines that there is an obstacle in the lateral direction Ac (YES), the automatic driving control device 210 executes the next process S7, which acquires the lateral distance of the obstacle.

[0057] In process S7, the behavior management unit 211 acquires the lateral distance Dc of an obstacle such as the partition wall W shown in FIG. 5 based on, for example, the position information of the obstacle detected by the external sensor 182 and the position information of the work machine 100 detected by the position sensor 181. Note that the automatic driving control device 210 may acquire the lateral distance Dc of the obstacle based on the position information of the obstacle stored in memory and the position information of the work machine 100 detected by the position sensor 181.

[0058] Here, the lateral distance Dc of an obstacle is the distance from the part of the work machine 100 closest to the obstacle in the lateral direction Ac perpendicular to the approach direction Af. In the example shown in Fig. 5, the lateral distance Dc of the partition wall W, which is the obstacle, is the distance between the right front end of the right front wheel 114 of the left and right front wheels 114, 114 of the work machine 100, and the partition wall W. Note that information regarding the position and dimensions of each part of the work machine 100 is recorded, for example, in the memory of the automatic driving control device 210, and therefore the behavior management unit 211 can obtain the position of each part of the work machine 100 based on the position information of the work machine 100.

[0059] Next, the automatic driving control device 210 executes process S8 to calculate the deviation amount ΔD of the excavation position Pe. In this process S8, the path planning unit 212 generates, for example, a straight path Rs based on the straight direction As of the work machine 100 that has reached the run-up start position P0, as the target path Rt. This straight path Rs is, for example, a path that starts from the current position Pp of the work machine 100 and ends at the excavation position Pe' of the excavation target E in the straight direction As, which is the current direction Ap of the work machine 100.

[0060] The behavior management unit 211 also calculates the amount of deviation ΔD of the work machine 100 in the lateral direction Ac based on, for example, the run-up distance De, which is the distance of the run-up path Ra that travels straight in the run-up direction Af from the run-up start position P0 to the excavation position Pe, and the angle error Δθ. The amount of deviation ΔD is the distance in the lateral direction Ac between the work machine 100 that has traveled along the run-up path Ra from the run-up start position P0 to reach the excavation position Pe, and the work machine 100 that has traveled along the straight path Rs from the run-up start position P0 to reach the excavation position Pe'. The amount of deviation ΔD can be calculated, for example, by the formula: ΔD=De×tan Δθ.

[0061] Next, the automatic driving control device 210 executes process S9 to determine whether the deviation amount ΔD is equal to or greater than the lateral distance Dc of the obstacle. In process S9, if the behavior management unit 211 determines that the deviation amount ΔD of the excavation position Pe is less than the lateral distance Dc of the obstacle (NO), that is, that there is no possibility of contact between the work machine 100 and the obstacle, the automatic driving control device 210 executes automatic excavation in process S12, which will be described later.

[0062] On the other hand, in this process S9, if the behavior management unit 211 determines that the deviation ΔD of the excavation position Pe is greater than or equal to the lateral distance Dc of the obstacle (YES), that is, that there is a possibility of contact between the work machine 100 and the obstacle, the automatic driving control device 210 executes process S10 to generate the next corrected route.

[0063] Figure 7 is a plan view illustrating process S10 for generating the corrected path of Figure 4. As shown in Figure 7(a), it is assumed that, after process S2 for executing the automatic traveling described above, an error has occurred between the actual position Pp and direction Ap of the work machine 100 that was determined to have reached the run-up start position P0 in process S3 described above, and the run-up start position P0 and run-up direction Af. In this case, the path planning unit 212 generates, for example, as the corrected path Rc, a turning path Rk that moves the work machine 100 backward from the current position Pp to a turning position Pc, and then moves the work machine 100 forward from the turning position Pc to the run-up start position P0 so that the work machine 100 faces the excavation target E and faces the run-up direction Af.

[0064] As shown in (a) of Figure 7, the path planning unit 212 sets the turning position Pc of the turning path Rk on a straight line L that passes through the midpoint of the line segment connecting the current position Pp of the work machine 100 and the run-up start position P0, and the intersection of the current direction Ap of the work machine 100 and the run-up direction Af. This makes it possible to generate a simple corrected path Rc in which the backward path of the turning path Rk, shown by the dashed line, and the forward path of the turning path Rk, shown by the solid line, are symmetrical with respect to the straight line L. Furthermore, by bringing the turning position Pc on the straight line L closer to the current position Pp of the work machine 100 within a range that allows the work machine 100 to follow the turning path Rk, the travel distance of the work machine 100 can be reduced, and work efficiency can be improved.

[0065] Figure 8 is a graph showing the relationship between the distance from the current position Pp of the work machine 100 in Figure 7 to the turning position Pc, and the spacing Dw and length Dl of the partition walls W. In the example shown in Figure 5, the obstacles in the lateral direction Ac of the work machine 100 are a pair of partition walls W in the stockyard provided on both sides of the stockpile of the object to be excavated E. Such a pair of partition walls W are provided on both sides of the object to be excavated E at a predetermined spacing Dw, and extend a predetermined length Dl along the approach direction Af of the work machine 100.

[0066] In this case, the path planning unit 212 sets the turning position Pc so that, for example, as shown in Figure 8, the narrower the spacing Dw between the pair of partitions W and the longer the length Dl, the longer the distance Pp-Pc from the current position Pp of the work machine 100, which is the starting position of the turning path Rk, to the turning position Pc.

[0067] In addition, in this process S10, it is assumed that an angular error Δθ has occurred between the current direction Ap of the work machine 100 that has reached the run-up start position P0 and the run-up direction Af facing the excavation target E, as shown in Figure 7(b). It is also assumed that the run-up distance De from the run-up start position P0 to the excavation position Pe is equal to or longer than the minimum run-up distance Dm. In this case, the path planning unit 212 may, for example, calculate a forward movement corrected path Rf that corrects the angular error Δθ by moving the work machine 100 forward toward the excavation target E before generating the turning path Rk shown in Figure 7(a).

[0068] In this process S10, once the corrected forward path Rf has been generated by the path planning unit 212, the automatic driving control device 210 executes automatic excavation in S12, which will be described later, as shown by the dashed line in Fig. 4. In this case, as shown in Fig. 7(b), the direction Ap of the work machine 100 moving forward along the corrected forward path Rf is corrected so that it coincides with the run-up direction Af facing the excavation target E at position P0'. Furthermore, it becomes possible for the work machine 100 to travel the distance Ds from the corrected run-up start position P0' to the excavation position Pe along the corrected straight path Rs' that coincides with the run-up path Ra, and to arrive at the excavation position Pe at a speed required for excavating the excavation target E.

[0069] On the other hand, in this process S10, for example, if the run-up distance De is shorter than the minimum run-up distance Dm, the route planning unit 212 generates a switching route Rk as shown in (a) of Fig. 7. Thereafter, the automatic driving control device 210 executes automatic traveling in process S11. In this process S11, the behavior management unit 211 outputs an operation command MC for the work machine 100 to the action generation unit 213. More specifically, the behavior management unit 211 outputs an operation command MC to the action generation unit 213, which includes a traveling command TC for transitioning the work machine 100 to a travel mode and traveling along the corrected route Rc.

[0070] As a result, similar to process S2 described above, the operation generation unit 213 outputs a hydraulic control signal Sh, an engine control signal Se, and a travel control signal St to the hydraulic control device 220, the engine control device 230, and the travel control device 240, respectively. As a result, the work machine 100 travels, the speed of the work machine 100 is controlled, and the work machine 100 moves backward, forward, or turns while following the corrected path Rc. The automatic driving control device 210 also executes process S3 described above at a predetermined cycle, determines whether the work machine 100 has reached the run-up start position P0, and repeats process S3 and subsequent processes.

[0071] On the other hand, if the path planning unit 212 determines in the above-mentioned process S6 that there is no obstacle in the lateral direction Ac (NO), or if it determines in the above-mentioned process S9 that the deviation amount ΔD of the excavation position Pe is less than the lateral distance Dc of the obstacle (NO), the automatic driving control device 210 executes process S12. In this process S12, the automatic driving control device 210 executes automatic excavation of the vehicle body 110 because there is no possibility that the work machine 100 will come into contact with an obstacle in the lateral direction Ac.

[0072] In this process S12, the behavior management unit 211 outputs a motion command MC for the work machine 100 to the motion generation unit 213. More specifically, the behavior management unit 211 outputs to the motion generation unit 213 a motion command MC including an excavation command EC for transitioning the work machine 100 to the excavation mode and causing it to travel along the straight path Rs.

[0073] The action generation unit 213 outputs a hydraulic control signal Sh, an engine control signal Se, and a travel control signal St to the hydraulic control device 220, the engine control device 230, and the travel control device 240, respectively, based on the action command MC input from the behavior management unit 211. As a result, the engine control device 230 controls the rotation speed of the engine 140, power is transmitted to the front differential 116 and the rear differential 117 via the power transmission mechanism 160, the left and right front wheels 114, 114 and the left and right rear wheels 115, 115 are driven, and the work machine 100 travels.

[0074] Furthermore, hydraulic pump 150 is driven by rotation of the drive shaft of engine 140, and hydraulic oil is supplied to control valve 170. Furthermore, control valve 170 is controlled by hydraulic control device 220, causing lift cylinder 122 to contract and lower bucket 123 to the vicinity of the ground surface, and bucket cylinder 126 to extend or contract and point the edge of bucket 123 toward object to be excavated E. As a result, work machine 100 travels straight along straight path Rs' that coincides with run-up path Ra, and when it reaches a predetermined speed, the edge of bucket 123 plunges into object to be excavated E, and object to be excavated E is excavated and scooped up by bucket 123.

[0075] The operation of the control device 200 for a work machine according to this embodiment will now be described.

[0076] As described above, the construction machine control device 200 of this embodiment includes an automatic driving control device 210 that causes the construction machine 100 to automatically excavate the excavation target E. As described above, the automatic driving control device 210 is equipped with a behavior management unit 211, a path planning unit 212, and an action generation unit 213. The behavior management unit 211 acquires the run-up start position P0 from which the construction machine 100 starts moving straight toward the excavation target E when it starts automatic excavation, and outputs an action command MC that includes an excavation command EC for the work machine 100. The path planning unit 212 generates a target route Rt that includes a straight route Rs based on the straight traveling direction As of the work machine 100 that has reached the run-up start position P0. The action generation unit 213 outputs a hydraulic control signal Sh, an engine control signal Se, and a travel control signal St, which are control signals based on the action command MC and the target route Rt, to cause the work machine 100 to perform automatic excavation or automatic travel. The behavior management unit 211 also acquires the angular error Δθ in the straight-ahead direction As based on the run-up direction Af facing the excavation target E at the run-up start position P0, and the lateral distance Dc to an obstacle such as a bulkhead W that is located at a distance from the work machine 100 in a lateral direction Ac perpendicular to the run-up direction Af. Furthermore, the behavior management unit 211 acquires the run-up distance De, which is the distance in the run-up direction Af from the work machine 100 to the excavation target E, and determines whether or not there is a possibility of contact between the obstacle and the work machine 100 based on the angular error Δθ, the lateral distance Dc, and the run-up distance De. If the behavior management unit 211 determines that there is a possibility of contact, the path planning unit 212 generates a corrected path Rc that corrects the angular error Δθ as the target path Rt. Furthermore, the behavior management unit 211 outputs a traveling command TC as an operation command MC, and the operation generation unit 213 outputs a control signal based on the traveling command TC and the corrected route Rc to cause the work machine 100 to perform automatic traveling along the corrected route Rc. On the other hand, if the behavior management unit 211 determines that there is no possibility of contact, the behavior management unit 211 outputs an excavation command EC as the operation command MC, and the operation generation unit 213 outputs a control signal based on the excavation command EC and the straight route Rs to cause the work machine 100 to perform automatic excavation, including automatic traveling along the straight route Rs.

[0077] With this configuration, the construction machine control device 200 of this embodiment can cause the construction machine 100 to perform stable excavation work while avoiding contact between the construction machine 100 and the obstacle, even if an obstacle, such as a stockyard bulkhead W, is present in the lateral direction Ac of the construction machine 100. More specifically, even if an angular error Δθ occurs between the straight-ahead direction As and the approach direction Af of the construction machine 100 at the approach start position P0 for excavating the excavation target E due to an error in the direction of the construction machine 100 or the unevenness of the ground surface, a corrected path Rc that can avoid contact with the obstacle is generated. Therefore, the construction machine control device 200 of this embodiment can avoid contact with obstacles that may be present around the excavation target E when the construction machine 100 automatically excavates the excavation target E while ensuring the speed of the construction machine 100 necessary for excavating the excavation target E.

[0078] Furthermore, in the construction machine control device 200 of this embodiment, the behavior management unit 211 determines the presence or absence of an obstacle such as a partition wall W based on the output of the external sensor 182 that detects objects around the construction machine 100. Then, if the behavior management unit 211 determines that there is no excavation target E (NO) in process S6 of Figure 4, it outputs an excavation command EC as a motion command MC in process S12 without determining the possibility of contact between the construction machine 100 and the obstacle in process S9. In this case, the motion generation unit 213 outputs a control signal based on the excavation command EC and the straight path Rs to cause the construction machine 100 to perform automatic excavation, including automatic traveling along the straight path Rs.

[0079] With this configuration, the construction machine control device 200 of this embodiment can reduce the amount of processing by omitting the process of determining the possibility of contact with an obstacle when there is no obstacle such as the partition wall W. This shortens the processing time taken by the construction machine control device 200, and improves the efficiency of automatic excavation by the construction machine 100.

[0080] Furthermore, in the construction machine control device 200 of this embodiment, when the behavior management unit 211 determines that there is a possibility of contact between the construction machine 100 and an obstacle, the path planning unit 212 generates a corrected path Rc, which is a turning path Rk that moves the construction machine 100 backward in a direction away from the excavation target E and then forward toward the excavation target E to correct the angle error Δθ.

[0081] With this configuration, the construction machine control device 200 of this embodiment can correct the angular error Δθ between the straight ahead direction As and the approach direction Af of the construction machine 100 at the approach start position P0 when an obstacle such as a bulkhead W is present, thereby making it possible to avoid contact with the obstacle. Also, by reversing the construction machine 100 along the turning path Rk, it is possible to more reliably ensure the minimum approach distance Dm required to excavate the excavation target E.

[0082] Furthermore, in the construction machine control device 200 of this embodiment, the path planning unit 212 acquires, for example, as shown in FIG. 7(b), a run-up distance De, which is the distance in the run-up direction Af from the work machine 100 to the excavation target E. Then, when the run-up distance De is equal to or longer than the minimum run-up distance Dm of the work machine 100 required to excavate the excavation target E, the path planning unit 212 generates, as a corrected path Rc, a forward corrected path Rf that moves the work machine 100 forward toward the excavation target E to correct the deviation ΔD. Furthermore, when the run-up distance De is shorter than the minimum run-up distance Dm, the path planning unit 212 generates a turning path Rk as a corrected path Rc, as shown in FIG. 7(b).

[0083] With this configuration, the work machine control device 200 of this embodiment can correct the angle error Δθ without reversing the work machine 100 when the run-up distance De from the run-up start position P0 to the digging position Pe is equal to or greater than the minimum run-up distance Dm. Therefore, the work machine control device 200 of this embodiment can further improve the work efficiency of the work machine 100 when it is automatically digging.

[0084] Furthermore, in the construction machine control device 200 of this embodiment, the obstacles in the lateral direction Ac of the work machine 100 include a pair of partitions W that are provided on either side of the lateral direction Ac of the excavation target E with a distance Dw between them and have a length Dl along the approach direction Af. The turning path Rk shown in Fig. 7(a) includes a position Pp that is the start position where the work machine 100 begins to move backward, and a turning position Pc where the work machine 100 switches between moving backward and forward. The path planner 212 sets the approach start position P0 so that the distance from position Pp, the start position of the turning path Rk, to the turning position Pc increases as the distance Dw between the pair of partitions W decreases and the length Dl increases, as shown in Figs. 8(a) and 8(b).

[0085] With this configuration, the work machine control device 200 of this embodiment can reliably correct the position Pp and direction Ap of the work machine 100 using the run-up start position P0 or the corrected run-up start position P0' and run-up direction Af. This not only makes it possible to more reliably avoid contact between the work machine 100 and the pair of partitions W, even when the distance Dw between the pair of partitions W is narrow and the length Dl is long, but also makes it possible to avoid repeated corrections to the corrected path Rc, improving the work efficiency of the work machine 100.

[0086] As described above, according to this embodiment, it is possible to provide a construction machine control device 200 that can cause the construction machine 100 to perform stable excavation work while avoiding contact between the construction machine 100 and obstacles.

[0087] The above has described in detail an embodiment of a work machine control device according to the present invention using the drawings, but the specific configuration is not limited to this embodiment, and even if there are design changes and the like within the scope of the present invention, they are also included in the present invention. [Explanation of symbols]

[0088] 100 Work Machinery 182 External Sensor 200 Control device for work machine 211 Behavior Management Department 212 Route Planning Department 213 Motion generator Ac Lateral direction Af Approach direction As straight ahead Dc lateral distance De Run-up distance (distance in the run-up direction) Dl length Dm Minimum run-up distance Ds Corrected straight path distance Dw Interval E. Excavation target EC Drilling Directive MC operation command P0 Starting position of approach P0' Corrected run-up start position Pc Turning point Pp position (starting position) Rc correction path Rf forward correction path Rk Switching Path Rs Straight Route Rs' Corrected straight path Rt target route Se Engine control signal (control signal) Sh Hydraulic control signal (control signal) St. Travel control signal (control signal) TC travel command W Bulkhead (obstacle) Δθ Angle error

Claims

1. A control device for a work machine that causes a work machine to automatically excavate an excavation target, a behavior management unit that acquires a run-up start position at which the work machine starts moving straight toward the excavation target when the work machine starts automatic excavation, and outputs an operation command including an excavation command for the work machine; a path planning unit that generates a target path including a straight path based on the straight direction of the work machine that has reached the run-up start position; an operation generating unit that outputs a control signal based on the operation command and the target route to cause the work machine to perform automatic excavation or automatic traveling; the behavior management unit determines whether or not there is a possibility of contact between the obstacle and the work machine based on an angle error in the straight-ahead direction based on an approach direction facing the excavation target at the approach start position, a lateral distance from the work machine to an obstacle located at a position separated in a lateral direction perpendicular to the approach direction, and a distance in the approach direction from the work machine to the excavation target, When the behavior management unit determines that there is a possibility of contact, the path planning unit generates a corrected path that corrects the angle error as the target path; the behavior management unit outputs a travel command as the operation command, the operation generation unit outputs a control signal based on the travel command and the corrected path to cause the work machine to perform automatic travel along the corrected path; When the behavior management unit determines that there is no possibility of contact, the behavior management unit outputs an excavation command as the operation command, the operation generation unit outputs a control signal based on the excavation command and the straight path to cause the work machine to perform automatic excavation including automatic traveling along the straight path. Control device for work machine.

2. the behavior management unit determines whether or not the obstacle is present based on an output from an external sensor that detects objects around the work machine; When the behavior management unit determines that the obstacle does not exist, the behavior management unit outputs the excavation command as the operation command without determining whether or not there is a possibility of contact; the operation generation unit outputs a control signal based on the excavation command and the straight path to cause the work machine to perform automatic excavation including automatic traveling along the straight path. The control device for a work machine according to claim 1.

3. When the behavior management unit determines that there is a possibility of contact, the path planning unit generates, as the corrected path, a turning path in which the work machine is moved backward in a direction away from the excavation object and then moved forward toward the excavation object to correct the angle error. The control device for a work machine according to claim 1.

4. The route planning unit when a run-up distance in the run-up direction from the work machine to the excavation object is equal to or longer than a minimum run-up distance of the work machine required to excavate the excavation object, a forward corrected path is generated as the corrected path, which moves the work machine forward toward the excavation object to correct the angle error; If the run-up distance is shorter than the minimum run-up distance, the turning path is generated as the corrected path. The control device for a work machine according to claim 3.

5. The obstacle includes a pair of partition walls provided on both sides of the excavation target in the lateral direction with a gap therebetween and having a length along the approach direction, the switching path includes a start position where the work machine starts to move backward, and a switching position where the work machine switches between moving backward and forward, the path planning unit sets the turning position such that the distance from the start position of the turning path to the turning position increases as the gap between the pair of partition walls decreases and the length increases. The control device for a work machine according to claim 3.

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