Control system of dump trucks

Abstract

The dump truck has a controller that controls the dump truck to travel on a travel path and stop at a designated loading position. The controller calculates the forward and backward direction (first stopping direction) of the dump truck when it travels on the travel path and stops at the designated loading position from the travel path data. Based on the calculated first stopping direction, the position data of the designated loading position, and the rotation center position data of the excavator, the controller corrects the travel path and calculates the corrected travel path in a manner that places the excavator on the extension line of the forward and backward direction (second stopping direction) of the dump truck when it travels on the corrected travel path ending at the designated loading position and stops at the designated loading position.

Description

Technical Field

[0001] This invention relates to the control system of dump trucks. Background Technology

[0002] In recent years, there has been a growing demand for autonomous dump trucks (autonomous driving dump trucks) in mining operations, aimed at reducing labor costs and improving safety. These trucks operate without human intervention, following routes received via satellite. One of the fundamental operations in mining is loading, where an operator-controlled excavator loads goods onto an autonomous dump truck. During loading, the excavator is usually positioned on a platform known as the work face; therefore, to facilitate loading operations, it is desirable for the autonomous dump truck to park as close to the work face as possible.

[0003] Patent Document 1 describes an autonomous dump truck that receives a path guided towards a designated loading position via wireless communication and travels along that path. This designated loading position is specified by the excavator (loading machinery) operator (excavator operator) for loading goods onto the dump truck. The document proposes that when stopping, the truck compares the designated loading position with the position of the work surface detected by a rear-mounted identification device, controlling the truck to stop closer to the excavator. Through this control, the dump truck stops at a position that avoids contact with the work surface and is as close as possible to the designated loading position—that is, a position easily accessible to the excavator operator for loading operations—thus improving loading efficiency.

[0004] Existing technical documents

[0005] Patent documents

[0006] Patent Document 1: Japanese Patent Application Publication No. 2018-142113 Summary of the Invention

[0007] Mining environments present a variety of conditions. Therefore, it is not always possible to chart a path that will allow the dump truck to stop at the designated loading position in a direction easily accessible to the excavator operator.

[0008] Patent Document 1 describes an autonomous dump truck that can stop as close as possible to the designated loading position without colliding with the work surface. However, for the excavator operator, the direction of the dump truck (cargo box) at this stopping position is not necessarily the direction that is easiest to load. For example, when loading goods from the excavator into the cargo box of the dump truck, the longitudinal direction (long side) of the front working device is aligned with the longitudinal direction of the cargo box, and the bucket is tilted while the front working device moves along the longitudinal direction of the cargo box. This usually prevents the goods from concentrating in one place in the cargo box. In this case, if the autonomous dump truck stops with the longitudinal direction of the cargo box intersecting the longitudinal direction of the excavator's front working device, moving the front working device along the longitudinal direction of the cargo box would require a simultaneous rotational motion, which could increase the difficulty of operation, excavator operator fatigue, and cycle time.

[0009] Therefore, when a loading location is designated, it is desirable to draw a path that is as parallel as possible to the longitudinal direction of the front working device, so that when the autonomous dump truck stops, the orientation (longitudinal direction) of the truck body is nearly parallel to the longitudinal direction of the front working device. However, because the environment around the loading yard changes continuously, it is difficult for a higher-level map generation system (for example, a server) with the function of sending maps to the autonomous dump trucks to fully grasp the changes around the loading yard and set the driving paths for each autonomous dump truck.

[0010] Therefore, in order to park the excavator in a manner that makes the forward and backward direction of the excavator's front working device nearly parallel to the forward and backward direction of the autonomous dump truck, as described above, the autonomous dump truck needs to identify the surrounding environment and adjust its path accordingly.

[0011] In summary, the purpose of this invention is to provide a control system for an autonomous dump truck that can stop at a designated loading location in an orientation that is easy for the operator of the loading machinery to load.

[0012] This application includes several solutions to the aforementioned problems. One example is a control system for a dump truck, which is an autonomous dump truck with a control device. This control device outputs control signals to control the dump truck by causing it to travel along the travel path and stop at a designated loading position, based on travel path data and the dump truck's position data. The travel path is the dump truck's path of travel and ends at the designated loading position, which is a position specified as the location where a loading machine loads goods into the dump truck's cargo bed. The control device calculates a first stopping direction based on the travel path data. The first stopping direction is the forward / backward direction of the dump truck when it travels on the driving path and stops at the designated loading position. The control device, based on the calculated first stopping direction, the position data of the designated loading position, and the position data of the loading machinery, corrects the driving path by positioning the loading machinery on the extension line of the second stopping direction and calculates the corrected driving path. The corrected driving path is the driving path that has been corrected and ends at the designated loading position. The second stopping direction is the forward / backward direction of the dump truck when it travels on the corrected driving path and stops at the designated loading position.

[0013] Invention Effects

[0014] According to the present invention, an autonomous dump truck can be stopped at a designated loading position in an orientation that is easy for the operator of the loading machinery to load. Attached Figure Description

[0015] Figure 1 This is an external view of an example of a self-driving dump truck according to an embodiment of the present invention.

[0016] Figure 2 This is a schematic diagram of the control system of a dump truck according to an embodiment of the present invention.

[0017] Figure 3 This is a functional block diagram of the controller according to an embodiment of the present invention.

[0018] Figure 4 This is an illustration of the driving path of an autonomous dump truck.

[0019] Figure 5 This is a geometric diagram used to explain the logic of generating a modified driving path based on the modified path generation unit 31.

[0020] Figure 6This is a top view of the excavator 200 in the posture of moving from the designated loading position P0 to the operating plane 56 of the working device 50.

[0021] Figure 7 This is an illustration of the detection range of LIDAR (obstacle sensor).

[0022] Figure 8 This diagram shows the situation where obstacles are detected when the dump truck 100 is traveling on the original driving path 61 after the modified driving path 62 is generated.

[0023] Figure 9 This diagram illustrates the situation where, when the dump truck 100 wants to travel on the modified travel path 62 or is traveling on the modified travel path 62, it detects obstacles that were not detected during its travel on the original travel path 61.

[0024] Figure 10 This is a functional block diagram of the driving control unit 33.

[0025] Figure 11 This is an example of a flowchart of the process performed by the controller 30 in this embodiment. Detailed Implementation

[0026] Hereinafter, embodiments of the present invention will be described using the accompanying drawings.

[0027] Figure 1 This is a perspective view (perspective view) of an example of a self-driving dump truck according to an embodiment of the present invention. Figure 1 The dump truck 100 has a chassis 2, a cargo box 3 rotatably supported on the chassis 2 by a support shaft (not shown), a front compartment 4 mounted on the chassis 2, a plurality of front wheels 5 mounted on the front of the chassis 2, and a plurality of rear wheels 6 mounted on the rear of the chassis 2.

[0028] The compartment 4 contains a driver's seat (not shown). Sometimes the operator (driver) sits in this seat to operate the brake and accelerator pedals, etc. That is, the dump truck 100 is sometimes manually driven. Inside the cargo bed 3, soil and sand are loaded as cargo (transported goods) by loading machinery (construction machinery) such as hydraulic excavators and wheel loaders. Additionally, at the dump truck 100's transport destination (unloading site), the cargo bed hydraulic cylinder 15 (see reference)... Figure 2 While extending, the hopper 3 rotates around the support shaft at the rear end of the hopper 3, and the front end of the hopper 3 rises and tilts, thereby allowing the goods loaded in the hopper 3 to be discharged from the rear end of the hopper 3.

[0029] The front wheels 5 (5L, 5R) are rotatably mounted on the lower front side of the chassis 2. The front wheel 5L is located on the left side of the chassis 2, and the front wheel 5R is located on the right side of the chassis 2. These left and right front wheels 5L and 5R constitute the steering wheels whose steering angle θ is changed by the steering device. The left and right front wheels 5L and 5R are steered by the steering device according to the rotation angle of the steering wheel of the dump truck 100.

[0030] The rear wheels 6 (6L, 6R) are rotatably mounted on the rear side of the chassis 2. Rear wheel 6L is located on the left side of the chassis 2, and rear wheel 6R is located on the right side of the chassis 2. These left and right rear wheels 6L and 6R constitute the drive wheels of the dump truck 100, powered by left and right electric drive motors 19L and 19R (see reference). Figure 2 Rotation drive. The left and right rear wheels 6L and 6R are rotated, thereby driving the dump truck 100.

[0031] The chassis 2 is also equipped with an electric motor 19, which serves as an acceleration and deceleration device for controlling the acceleration and deceleration of the rear wheels 6 (see reference). Figure 2 The main components, such as the shock absorbers (suspension devices) that can support the front wheels 5 and the rear wheels 6 vertically, constitute the structure that allows the vehicle to move freely on the road surface via the front wheels 5 and the rear wheels 6.

[0032] Figure 2 This is a schematic diagram of the control system of a dump truck according to an embodiment of the present invention. The autonomous dump truck 100 includes: an engine 11; an alternator (generator) 12 driven by the engine 11 and a hydraulic pump 13; a hydraulic circuit 14 that controls the flow of working oil (hydraulic oil) supplied from the hydraulic pump 13 to various hydraulic actuators (e.g., the cargo box hydraulic cylinder 15, the steering hydraulic cylinder 16); a cargo box hydraulic cylinder 15 that receives the working oil supply from the hydraulic circuit 14 and extends or retracts to raise or lower the cargo box 3; and an electric steering motor that inputs steering torque to the steering column shaft (not shown) connected to the steering wheel (not shown) to operate the steering valve (not shown). 17; left and right steering hydraulic cylinders 16 that change the steering angle of the left and right front wheels 5L and 5R by supplying and discharging working oil through the steering valve; left and right electric travel motors 19 (19L and 19R) that apply torque to the left and right rear wheels 6 (6L and 6R) to control the acceleration and deceleration of the dump truck 100; inverters 18 that supply power generated by the alternator 12 to the left and right electric travel motors 19 and electric steering motors 17 based on control signals from the controller 30; and controllers (control devices) 30 that output control signals to the inverters 18 and other devices based on various input information.

[0033] (Controller 30)

[0034] The controller (control device) 30 is a control device (e.g., a microcomputer) that includes an arithmetic processing unit (e.g., a processor such as a CPU), a memory device (e.g., a semiconductor memory such as ROM or RAM), input / output circuits, and communication circuits. It is configured to execute various processes specified by the program stored in the memory device by executing the program stored in the memory device through the arithmetic processing unit. The controller 30 performs control of the electric drive motors 19L and 19R and the electric steering motor 17 (that is, control of the acceleration, deceleration, and steering of the dump truck 100) by outputting control signals to the inverter 18 for the autonomous driving of the dump truck 100, and performs path correction processing when the dump truck 100 is autonomously driving.

[0035] Wireless device 83 is connected to controller 30 (see reference) Figure 3 It can communicate with external terminals (such as a server (computer) 300 located in the control center, and a device mounted on the excavator 200). Figure 6 The controllers of the controller 30 communicate wirelessly with each other. The wireless device 83 transmits data output from the controller 30 through the wireless device antenna (not shown), and on the other hand, inputs data received by the wireless device antenna (e.g., driving path data described later) to the controller 30.

[0036] The controller 30 receives the following data as input: rotation center position data as position data of the loading machinery, i.e., the excavator 200; and data on the location of the loader, as determined by an obstacle sensor (e.g., LIDAR, see reference). Figure 3 , 4 The obstacle position data (obstacle coordinates) detected by the GNSS receiver 84 mounted on the dump truck 100 in the direction of travel (rear), the position data of the dump truck 100 (its own position data) calculated by the GNSS receiver 84 mounted on the dump truck 100, the attitude data of the dump truck 100 (including the azimuth data of the dump truck 100) calculated by the output of the IMU (not shown) mounted on the dump truck 100 and the GNSS receiver 84, the steering angle data obtained by the steering angle sensor 81 mounted on the dump truck 100, and the speed data obtained by the speed sensor 82 mounted on the dump truck 100, etc.

[0037] The controller calculates the drive torque of the left and right drive motors 19 and electric steering motor 17 based on the following data received wirelessly from the server 300 at the control center: the driving path data of the dump truck 100, the position data of the excavator 200 (rotation center position data), the position data of obstacles detected by the obstacle sensor 21 (which detects obstacles in the direction of travel of the dump truck 100), the position data of the dump truck 100 calculated by the GNSS receiver 84, the attitude data (azimuth data) of the dump truck 100 calculated from the positioning results of the GNSS receiver 84 (using multiple GNSS antennas (not shown), the driving speed of the dump truck 100 detected by the speed sensor 82, and the steering angle of the front wheel 5 detected by the steering angle sensor 81. The controller then controls the inverter 18 to operate each motor 17, 19 according to the calculation results. Power generated by the alternator 12 is supplied to each motor 17, 19 via the inverter 18, and each motor 17, 19 performs command-based actions. Hydraulic oil from hydraulic pump 13 is supplied to cargo bucket hydraulic cylinder 15 and steering hydraulic cylinder 16 via hydraulic circuit 14. Specifically, the steering valve in hydraulic circuit 14 is activated by driving electric steering motor 17, opening the oil passage from hydraulic pump 13 to steering hydraulic cylinder 16, thereby steering the front wheels 5.

[0038] Figure 3 This is a functional block diagram that categorizes the operations performed by the controller 30 using boxes. The controller 30 functions as a path correction generation unit 31, a rear obstacle detection unit 32, and a driving control unit 33.

[0039] The path generation unit 31 corrects the driving path 61 (see reference) specified in the driving path data received from the server 300 in a manner that allows the dump truck 100 to stop at a position and orientation (direction) that facilitates loading operations by the excavator 200, based on driving path data, excavator 200 position data (rotation center position data), dump truck 100 position data, and posture data. Figure 5 And generate the corrected driving path 62 (refer to...) Figure 5 ).

[0040] The rear obstacle determination unit 32 determines whether there is a possibility of collision with an obstacle when the dump truck 100 travels on the corrected travel path 62 generated by the path correction generation unit 31, based on the obstacle position data detected by the obstacle sensor 21 that detects obstacles existing in the direction of travel of the dump truck 100, and the data of the corrected travel path 62 generated by the path correction generation unit 31 (corrected travel path data). If the determination indicates that there is a possibility of contact with an obstacle, the rear obstacle determination unit 32 outputs to the driving control unit 33 that the corrected travel path 62 cannot be used as the travel path of the dump truck 100 (corrected path usage determination).

[0041] The driving control unit 33 calculates the target speed and target steering angle of the dump truck 100 in a manner that enables the dump truck 100 to travel on the original driving path 61 or the modified driving path 62, and generates torque commands to be output to the left and right electric driving motors 19L, 19R and electric steering motor 17 in a manner that achieves the calculated values, and outputs the generated torque commands to the corresponding motors 19L, 19R and 17.

[0042] Furthermore, the original and revised driving paths 61 and 62 are assigned by a series of points called nodes. That is, the set of position data of multiple nodes constituting each driving path becomes the driving path data. The position of each node can be defined, for example, on an orthogonal coordinate system (site coordinate system) with east as the +x direction, north as the +y direction, and a point within the mine as the origin. Figure 4 This is an explanatory diagram of the driving path. As shown in the diagram, each node n (where n is a natural number) in the driving path data is not only assigned its coordinates (Xn, Yn), but also its target speed Vn when the dump truck 100 passes through that node n. The controller 30 controls the acceleration or deceleration of the electric driving motor 19 based on the deviation between the actual speed obtained by the speed sensor 82 and the target speed Vn.

[0043] (Corrected path generation section 31)

[0044] Next, use Figure 5 The process of generating the corrected driving path 62 by the corrected path generation unit 31 will be described in further detail. Figure 5 This is a geometric diagram illustrating the logic of the path generation unit 31. The large black dots in the diagram represent the nodes of the original travel path 61 received from the server 300.

[0045] Point P0 in the diagram represents the node for loading at the designated location. Loading at the designated location P0 refers to the point where the excavator 200 uses the pre-operation device 51 (see reference). Figure 6The reference position for loading cargo into the dump truck 100's cargo bed 3, as specified by the operator of the excavator 200, is wirelessly transmitted directly or indirectly from the excavator 200's controller to the controller 30.

[0046] in addition, Figure 5 In the diagram, the position of the right rear wheel 6R is designated as PR, and the position of the left rear wheel 6L is designated as PL, when the dump truck 100 travels on the travel path 61 and stops at the loading designated position P0 (in the example shown, the center of the axle of the rear wheel 6 of the dump truck 100 is located at the loading designated position P0). The axle connecting the left and right rear wheels 6L and 6R is depicted by a solid line connecting the two points PR and PL. Sometimes the distance between points PR and PL is called the distance between the rear wheels, and this distance is designated as l. In addition, sometimes the forward and backward direction of the dump truck 100 in this case (when the dump truck 100 travels on the travel path 61 and stops at the loading designated position P0) is called the first stopping direction. The first stopping direction is a straight line in the xy plane of the field coordinate system that passes through the center of the dump truck 100 and through the loading designated position P0 along the long side of the dump truck 100. The first stopping direction is also the intersection line between the plane orthogonal to the rear axle of the dump truck 100 and the xy plane in the field coordinate system. Alternatively, the first stopping direction is also the straight line L1 extending the line segment connecting the endpoint node of the travel path 61 (i.e., the loading designated position P0) to the node Pz preceding the endpoint. The first stopping direction is calculated based on travel path data (e.g., the position data of the loading designated position P0 and node Pz contained in the travel path data).

[0047] Here, use Figure 6 The rotation center position Ps and point Ps' are described as points associated with excavator 200. Figure 6 It is a top view of the excavator 200 in the posture of moving from the designated loading position P0 to the operating plane 56 of the working device 50. Figure 6 The excavator 200 has a lower traveling body 55, an upper rotating body 54 rotatably mounted on the lower traveling body 55, and a front working device 50 mounted on the upper rotating body 54 and consisting of a boom 51, a stick 52, and a bucket 53. The operating plane 56 of the front working device 50 is the plane on which all the front parts 51, 52, and 53 constituting the front working device 50 can move. Figure 6 In this example, the center of the front working device 50 is located in the left-right direction. Point Ps is the position of the rotation center of the upper rotating body 54. Point Ps' is the foot of the perpendicular line drawn from the rotation center position Ps relative to the action plane 56 of the front working device 50. Here, the length of this perpendicular line is set to m. Figure 5The rotation center position Ps and point Ps' shown are the positions and points when the front working device 50 is maintained in the manner in which the action plane 56 passes through the loading designated position P0.

[0048] Furthermore, although the position of the excavator 200 is defined by the rotation center position Ps in this embodiment, it can be defined anywhere as long as the location of the two GNSS antennas (not shown) mounted on the upper rotating body 54 is known. The rotation center position Ps and the orientation of the forward working device 50 (upper rotating body 54) can be calculated by the GNSS receiver (not shown) mounted on the excavator 200 based on the signals (navigation signals) received by multiple positioning satellites from the two GNSS antennas.

[0049] return Figure 5 The straight line L2, shown by the dashed line, is a straight line on the xy plane in the field coordinate system. It is the straight line connecting point Ps', where the front working device 50 of the excavator 200 is held in the position such that the action plane 56 passes through the loading designated position P0, with the loading designated position P0. The position of the right rear wheel 6R is set as PR' when the dump truck 100 is stopped at the loading designated position P0 in the forward and backward direction (referred to as the "second stopping direction"), and the position of the left rear wheel 6L is set as PL'. The wheel axle is depicted by the dotted line connecting the two points PR' and PL'.

[0050] The center of rotation of excavator 200 is located at Figure 5 When the dump truck 100 stops at the designated loading position P0, as long as the direction of the dump truck 100 is kept in the second stopping direction (straight line L2) and it stops, the action plane 56 of the front working device 50 and the front-rear direction of the dump truck 100 are consistent in the xy plane, thus making the loading operation based on the excavator 200 easier.

[0051] Therefore, the path correction generation unit 31 of this embodiment corrects the travel path 61 and generates the corrected travel path 62 in such a way that the forward and backward direction (second stopping direction) of the dump truck 100 when it travels (reverses) on the corrected travel path 62 and stops at the loading designated position P0 is aligned with the straight line L2 (the action plane 56 passing through the loading designated position P0), or the angle between the second stopping direction and the straight line L2 is close to zero. More specifically, before the dump truck 100 reaches the loading designated position P0, the path correction generation unit 31 calculates the forward and backward direction of the dump truck 100 when it travels (reverses) on the uncorrected travel path 61 and stops at the loading designated position P0, i.e., the first stopping direction L1, based on the travel path data, and calculates the first stopping direction L1, the position data of the loading designated position P0, and the position data of the excavator 200. Figure 5 In the example, the data of the rotation center position is Ps, and the driving path 61 is corrected and the corrected driving path 62 is calculated in such a way that the second stopping direction is consistent with the straight line L2 (the action plane 56 passing through the loading specified position P0) or the angle between the second stopping direction and the straight line L2 is close to zero.

[0052] In this embodiment, when the path correction generation unit 31 corrects the driving path 61 to the corrected driving path 62, it utilizes... Figure 5 The two distances shown are d1 (first distance) and d2 (second distance). d1 (first distance) is the distance (deviation) in the first stopping direction (direction orthogonal to the rear axle) between the position PR (first position) of the rear wheel (first rear wheel) 6R of the dump truck 100 in the left-right direction when the dump truck 100 is traveling on the original travel path 61 and stops at the loading designated position P0, and the position PR' (second position) of the rear wheel (first rear wheel) 6R of the same side when the dump truck 100 is traveling on the original travel path 62 and stops at the loading designated position P0. d2 (second distance) is the distance (deviation) between the first position PR and the second position PR' in the direction orthogonal to the first stopping direction (direction of the rear axle). The calculation process of d1 (first distance) and d2 (second distance) based on the path correction generation unit 31 will be explained next.

[0053] Let θ be the angle between line L1 (first stopping direction) and line L2 (movement plane 56 passing through the loading specified position P0). If the coordinates of loading specified position P0 are set as (x0, y0), the coordinates of node Pz are set as (x1, y1), the coordinates of rotation center position Ps are set as (xs, ys), the coordinates of the foot of the perpendicular Ps' of the perpendicular line from rotation center position Ps to motion plane 56 are set as (xs', ys'), the length of the perpendicular line is set as m, the angle between line L1 and y-axis is set as θ1, and the angle between line L2 and y-axis is set as θ2, then θ is the difference between θ1 and θ2, which can be calculated by the following formula (1).

[0054]

Formula 1

[0055]

[0056] d1 (first distance) and d2 (second distance) are expressed by the following formulas (2) and (3) using θ calculated from the above formula (1) and the distance between the rear wheels. That is, d1 and d2 can be calculated based on the coordinates (x0, y0) of the loading position P0, the coordinates (x1, y1) of the node P1, the coordinates (xs', ys') of the foot of the perpendicular line from the rotation center position Ps to the action plane 56, and the distance between the rear wheels l.

[0057]

Formula 2

[0058]

[0059]

Formula 3

[0060]

[0061] The path correction generation unit 31 calculates point P1 (first point) on the original driving path 61, which is a distance d1 (first distance) away from the loading designated position P0; point P2 (second point) on the same driving path 61, which is a further distance X1 away from point P1 (first point); and point P3 (third point) on the same driving path 61, which is a further distance X2 away from point P2 (second point). Furthermore, the path correction generation unit 31 moves the driving path 61 between point P1 (first point) and point P2 (second point) parallel to each other by a distance d2 (second distance) in a direction orthogonal to the first stopping direction, and sets the points on the corrected driving path 62 after the parallel movement of points P1 and P2 as P1' and P2'. Furthermore, the path generation unit 31 calculates the path obtained by connecting point P1' and the loading designated position P0 with an arc centered at point PR' and smoothly connecting point P2' and point P3 as the corrected driving path 62 (the line connecting points P3, P2', P1', and P0).

[0062] Furthermore, the target speeds specified for each node on the revised driving path 62 can be inherited from the nodes corresponding to those on the unrevised driving path 61. The target speeds of newly generated nodes on the revised driving path 62 can be set, for example, by supplementing the target speeds based on known node values. Additionally, X1 and X2 used above are adopted considering the very low speed of the vehicle body during reverse alignment and the vehicle's handling performance; they can be set to a length that sufficiently satisfies handling requirements when driving on the revised driving path 62.

[0063] (Rear obstacle detection unit 32)

[0064] The rear obstacle detection unit 32 receives the coordinates (obstacle position data) of the rear obstacle from the obstacle sensor 21. Based on these rear obstacle coordinates and the position data of the corrected driving path 62, it determines whether the dump truck 100 will come into contact with the obstacle while traveling on the corrected driving path 62, and outputs a corrected path usage judgment (TRUE or FALSE) corresponding to the judgment result. The corrected path usage judgment is used in determining whether the dump truck 100 is traveling on the original driving path 61 or the corrected driving path 62. Figure 7 As shown, two LiDARs are mounted as obstacle sensors 21, capable of scanning a range of 1 / 2 × vehicle width W + α [m] along the longitudinal direction of the vehicle body. The double lines in the figure represent the scanning surface of the LiDARs.

[0065] Figure 8 This indicates the situation where, after the corrected driving path 62 is generated, the dump truck 100 travels on the original driving path 61, and the obstacle is detected by the obstacle sensor 21. For example... Figure 8 As shown, if the length of the vertical line from the rear obstacle coordinate Po1 received from the obstacle sensor 21 to the corrected driving path 62 is less than or equal to the width W of the dump truck 100, it is determined that there is a risk of collision between the dump truck 100 and the obstacle if the corrected driving path 62 is used. The rear obstacle determination unit 32 then outputs FALSE as a correction path. In other words, the dump truck 100 is controlled to travel on the original driving path 61. On the other hand, if the length of the vertical line is greater than the width W of the vehicle, or if no obstacle is detected by the obstacle sensor 21, the rear obstacle determination unit 32 outputs TRUE as a correction path.

[0066] Figure 9 This refers to a situation where, when the dump truck 100 intends to travel on the revised travel path 62, or while traveling on the revised travel path 62, the obstacle sensor 21 detects an obstacle that was not detected during travel on the original travel path 61. In this case, it is also related to... Figure 8 Similarly, if it is determined that using the corrected driving path 62 would pose a risk of collision between the dump truck 100 and the obstacle, the rear obstacle determination unit 32 outputs FALSE as a correction path determination. In other words, the dump truck 100 is controlled to travel on the original driving path 61. Furthermore, with... Figure 8Similarly, when the length of the vertical line is greater than the width W of the vehicle body, or when no obstacle is detected by the obstacle sensor 21, the rear obstacle determination unit 32 uses the determination as a path correction and outputs TRUE.

[0067] Furthermore, here, when the length of the vertical line is less than or equal to the vehicle width W, the rear obstacle detection unit 32 determines that there is a possibility of collision. However, the vehicle width W is only one example, and other thresholds can also be used. Additionally, here, only the distance between the corrected driving path 62 and the corrected driving path (the length of the vertical line) is considered for the correction path usage determination. However, it is also possible to determine whether the distance between the corrected driving path 62 and the original driving path 61 is less than or equal to the vehicle width W (a situation where a collision with an obstacle would occur while driving on the corrected driving path 62), and if so, to drive on the original driving path 61 if the distance is greater than the vehicle width W. Even when driving on the original driving path 61, it is possible to stop in front of the obstacle in the event of a collision.

[0068] (Driving Control Unit 33)

[0069] The driving control unit 33 uses the corrected driving path 62 when the obstacle judgment unit 32 outputs the corrected driving path, and uses the original driving path 61 when the obstacle judgment is TRUE, to control the driving of the dump truck 100.

[0070] Figure 10 This is a functional block diagram of the driving control unit 33. As shown in the figure, the driving control unit 33 includes a steering control unit 41 that controls the steering angle of the dump truck 100, and a speed control unit 42 that controls the speed of the dump truck 100.

[0071] (A) The situation before reaching point P0 on driving path 61 and point P1' on the corrected driving path 62.

[0072] The speed control and steering control based on the driving control unit 33 when the dump truck 100 travels to the loading designated position P0 of the original driving path 61 or to point P1' of the modified driving path 62 are as follows.

[0073] The speed control unit 42 performs feedback control based on the real-time speed of the dump truck 100 calculated from the sensor value (speed data) of the speed sensor 82 and the target speed specified at each node of the driving path, calculating the torque of the left and right electric travel motors 19L and 19R in a manner that makes the real-time speed of the dump truck 100 close to the target speed. However, since the alignment is assumed to be done by reversing, the target speed is assumed to be the minimum speed of the vehicle body, for example, 5 [km / h]. In addition, when approaching the loading designated position P0, the target speed is set to 0 [km / h] and the vehicle is fully braked to stop at the desired parking position.

[0074] The steering control unit 41 targets a point (forward gaze point) on the path ahead of the dump truck 100 at a fixed distance (forward gaze distance) in the direction of travel from the current position. It determines the target steering value based on the straight line connecting the current position and the forward gaze point, and the angle formed by this line and the current vehicle yaw angle. Considering a slow vehicle speed, the forward gaze distance is set to 10 [m]. After determining the target steering value, the steering control unit 41 calculates the torque command for the electric steering motor 17 through feedback control of the target steering value and the current steering angle.

[0075] The calculated torque commands for the driving electric motor and the electric steering motor are output to the inverter to drive each motor, thereby ensuring that the vehicle travels without deviating from the path.

[0076] (B) The case of traveling from point P1' to point P0 on the revised driving path 62.

[0077] The speed control when traveling from point P1' to the designated loading position P0 on the corrected travel path 62 is as follows.

[0078] When the dump truck 100 reaches point P1' on the corrected travel path 62, the rear wheel 6 of one of the left or right sides will reach the aforementioned point PL' or PR' first. The speed control unit 42 then sets the target speed of the rear wheel 6 of the side that has not yet reached the point to 5 km / h, and the target speed of the rear wheel 6 of the side that has reached the point to 0 km / h, to calculate the torque of the left and right electric travel motors 19L and 19R. Simultaneously, the steering control unit 41 outputs a torque command to the electric steering motor 17 so that the steering angle is parallel to the orientation of the dump truck 100's body. At this time, the dump truck 100 performs circular motion around the rear wheel 6 of the side that has reached point PL' or PR', causing the rear wheel 6 of the other side, which has not yet reached point PL' or PR', to approach point PL' or PR'. Finally, when the rear wheels 6 of both sides reach points PL' and PR' respectively and the steering angle is parallel to the vehicle body, the steering control unit 41 sets the torque command of each electric travel motor 19L and 19R to 0 to complete the stop.

[0079] On the other hand, when driving on the corrected driving path 62 while the path correction determination is TRUE, if the path correction determination is switched to FALSE, the driving path is quickly returned to the original driving path 61, and the above control is performed in the same way.

[0080] In addition, in the speed control unit 42, regardless of whether it is the corrected driving path 62, the coordinates of the obstacle behind and the current coordinates (position data) of the dump truck 100 are compared. If the distance between the two becomes less than a fixed distance, the truck will quickly stop by full braking to avoid collision with the obstacle behind.

[0081] (flow chart)

[0082] Here, an example of the control flow of the dump truck 100 executed by the controller 30 configured as described above will be explained. Figure 11 This is an example of a flowchart illustrating the processes executed by the controller 30 in this embodiment. The controller 30 executes at predetermined intervals. Figure 11 The process.

[0083] In S101, the controller 30 (path correction generation unit 31) receives driving path data from the server 300 of the control center via the wireless device 83.

[0084] In S102, the controller 30 (correction path generation unit 31) determines whether the terminal node of the driving path shown by the driving path data received in S101 is the loading designated position P0. If it is determined that the terminal node is the loading designated position P0, the process proceeds to S103; otherwise, the process ends.

[0085] In S103, the controller 30 (path correction generation unit 31) receives, for example, the position data of the excavator 200 (coordinates (xs, ys) of the rotation center position Ps) from the excavator 200, and calculates the coordinates (xs', ys') of point Ps' using these coordinates (xs, ys) and the coordinates (x0, y0) of the loading designated position P0. Furthermore, the controller 30 (path correction generation unit 31) calculates θ based on the calculated coordinates (xs', ys') of point Ps', the coordinates (x0, y0) of the loading designated position P0, the coordinates (x1, y1) of node Pz, and the aforementioned formula (1). Additionally, although not explicitly stated, the coordinates (x0, y0) of the loading designated position P0 and the coordinates (x1, y1) of node Pz, which define the straight line L1 (first stopping direction), are also included in the travel path data received in S101.

[0086] In S104, the controller 30 (path correction generation unit 31) determines whether θ calculated in S103 is 0. If θ≠0, it proceeds to S105; if θ=0, no path correction is needed, and the process ends.

[0087] In S105, the controller 30 (corrected path generation unit 31) calculates the distances d1 and d2 using θ calculated by S103 and the above formulas (2) and (3), and generates the corrected driving path 62 from the driving path 61 using the method described above.

[0088] In S106, the controller 30 (rear obstacle detection unit 32) receives the coordinates (obstacle position data) of the rear obstacle from the obstacle sensor 21. Based on the position data of the corrected driving path 62 generated in S105 and the coordinates of the rear obstacle, it determines whether the dump truck 100 will collide with the obstacle while traveling on the corrected driving path 62. If it determines that a collision with the obstacle will occur while traveling on the corrected driving path 62, it proceeds to S107; if it determines that a collision will not occur, it proceeds to S116.

[0089] In step S111, the controller 30 (driving control unit 33) causes the dump truck 100 to travel along the corrected driving path 62, controlling the driving of the dump truck 100 until the rear wheel 6 of either the left or right side reaches point PL' and point PR' (refer to...). Figure 5 any point of ).

[0090] In step S112, the controller 30 (driving control unit 33) causes the left and right rear wheels 6 to reach points PL' and PR' (refer to...) first. Figure 5 The rear wheel 6 of one side of the truck is stopped at any point, and the rear wheel 6 of the other side, which has not yet arrived, is driven at the target speed (5 km / h). The dump truck stops when the rear wheel 6 of the other side also arrives at either point PL' or PR' (S113), and the process ends. This allows the dump truck 100 to stop at the loading stop position P0 while the dump truck 100 is in a straight line L2 in the forward and backward direction, making loading operations based on the excavator 200 easier.

[0091] On the other hand, if it is determined that the dump truck 100 will collide with an obstacle when it is traveling on the modified travel path 62 in S106, the modified travel path 62 is abandoned (S107), and the process proceeds to step S108.

[0092] In step S108, the controller 30 (rear obstacle determination unit 32) determines whether the dump truck 100 will collide with an obstacle while traveling on the driving path 61, based on the position data of the driving path 61 before correction received from S101 and the coordinates of the rear obstacle. If it is determined that a collision with an obstacle will occur while traveling on the driving path 61, the process proceeds to S109; otherwise, it proceeds to S110.

[0093] In step S109, the controller 30 (driving control unit 33) causes the dump truck 100 to travel along the original driving path 61, and stops the dump truck 100 in front of the obstacle behind it, thus ending the process.

[0094] In step S110, the controller 30 (driving control unit 33) causes the dump truck 100 to travel along the original driving path 61, and stops the dump truck 100 at the designated loading position P0, thus ending the process.

[0095] In addition, Figure 11 The flowchart also includes the process of abandoning the corrected driving path 62 and using the original driving path 61 due to the presence of an obstacle (S106, 107, 108, 109, 110), but this process can be omitted when it is clear that there is no obstacle.

[0096] (Effect)

[0097] According to the above-described embodiment, the following effects can be obtained.

[0098] (1) In this embodiment, a corrected travel path 62 is generated such that the action plane 56 (straight line L2) of the front working device 50 (bucket 53) of the excavator 200 when it moves to the loading designated position P0 is consistent with the forward and backward direction (second stopping direction) of the dump truck 100 at the loading designated position P0. The dump truck is controlled to travel on the corrected travel path 62 and stop at the loading designated position P0. As a result, the difficulty of the excavator operator performing the loading operation can be reduced, the workload can be reduced, and unnecessary increases in cycle time can be prevented.

[0099] However, it is not necessary for the second stopping direction and the action plane 56 (straight line L2) to be completely aligned; the angle between them in the xy plane is sufficient to be close to zero. According to this viewpoint, as long as the excavator 200 is located on the extension line of the second stopping direction (straight line L2), the loading operation based on the excavator 200 becomes easier compared to situations where this is not the case. That is, the path correction generation unit 31 can calculate the first stopping direction L1 in the forward / backward direction of the dump truck 100 based on the travel path data, assuming the dump truck 100 is traveling (reverse) on the original travel path 61 and stops at the loading designated position P0. Based on the calculated first stopping direction L1, the position data of the loading designated position P0, and the position data of the excavator 200... Figure 5 In the example, the data of the rotation center position) Ps, and in order to make the excavator 200 be located on the extension line of the second stopping direction L2 of the dump truck 100 in the forward and backward direction as the dump truck 100 travels (reverses) on the corrected travel path 62 and stops at the loading specified position P0, the travel path 61 is corrected and the corrected travel path 62 is calculated.

[0100] (2) In this embodiment, the modified driving path 62 is generated based on a line segment after a portion of the original driving path 61 has been moved parallel to the original path. Therefore, the modified driving path 62 can be generated with minimal path correction, reducing the possibility of driving on a route completely different from the original driving path 61. Thus, the possibility of encountering unexpected obstacles can be suppressed.

[0101] (3) In this embodiment, when the dump truck 100 is traveling on the original travel path 61 and detects an obstacle, it is determined whether there is a possibility that the obstacle will come into contact with the dump truck 100 when traveling on the revised travel path 62. If there is a possibility of contact, the truck will not travel on the revised travel path 62, but will travel on the original travel path 61. As a result, the following situation can be avoided: in order to avoid the possibility of contact with the obstacle caused by traveling on the revised travel path 62, the dump truck 100 has to stop in front of the obstacle.

[0102] (4) In this embodiment, when the dump truck 100 detects an obstacle while traveling on the modified travel path 62, it is determined whether there is a possibility that the obstacle will come into contact with the dump truck 100 during travel on the modified travel path 62. If there is a possibility of contact, the travel path is switched back to the original travel path 61. This avoids the following situation: in order to avoid the possibility of contact with the obstacle while traveling on the modified travel path 62, the dump truck 100 has to stop in front of the obstacle.

[0103] (other)

[0104] Furthermore, the present invention is not limited to the embodiments described above, but includes various modifications that do not depart from the spirit and scope of the invention. For example, the present invention is not limited to having all the configurations described in the above embodiments, including examples where some configurations are deleted. In addition, it is also possible to add or replace the configuration of one embodiment with the configuration of another embodiment.

[0105] The above describes the case where the controller 30 for controlling the dump truck 100 is mounted on the dump truck 100. However, it is also possible that the controller 30 is not mounted on the dump truck 100. For example, the vehicle control of the dump truck 100 can be performed wirelessly by setting up a control center 300.

[0106] In the above, when the dump truck 100 is stopped at the loading stop position P0, the dump truck 100 is controlled so that the midpoint of the rear axle is located at the loading stop position P0. However, it is also possible to control the dump truck 100 based on a point other than the midpoint of the rear axle.

[0107] Furthermore, the various components of the controller 30 described above, along with their functions and execution processes, can be partially or entirely implemented in hardware (e.g., logic executed by integrated circuit design). Additionally, the components of the controller 30 described above can be a program (software) that implements the functions of the controller 30 by being read and executed by a processing unit (e.g., a CPU). The information in this program can be stored in, for example, semiconductor memory (flash memory, SSD, etc.), magnetic memory devices (hard disk drives, etc.), and recording media (disk, optical disk, etc.).

[0108] Furthermore, in the descriptions of the various embodiments above, the control lines and information lines only represent those deemed necessary for the description of that embodiment, and do not represent all the control lines and information lines required for the product. In practice, it can be understood that almost all components are interconnected.

[0109] Explanation of reference numerals in the attached figures

[0110] 2…Chassis, 3…Cargo box, 5…Front wheel, 6…Rear wheel, 11…Engine, 12…Alternator, 13…Hydraulic pump, 14…Hydraulic circuit, 15…Cargo box hydraulic cylinder, 16…Steering hydraulic cylinder, 17…Electric steering motor, 18…Inverter, 19…Electric travel motor, 21…Obstacle sensor, 30…Controller, 31…Path correction generation unit, 32…Rear obstacle detection unit, 33…Driving control unit , 41… Steering control unit, 42… Speed ​​control unit, 50… Front working device, 51… Boom, 52… Stick, 53… Bucket, 54… Upper rotating body, 55… Lower traveling body, 56… Action plane, 61… Travel path before correction, 62… Travel path after correction, 81… Steering angle sensor, 82… Speed ​​sensor, 83… Radio receiver, 84… GNSS receiver, 100… Autonomous dump truck, 200… Excavator, 300… Server.

Claims

1. A control system for a dump truck, the dump truck being an autonomous driving type and having a control device, the control device outputting a control signal to control the dump truck in a manner that causes the dump truck to travel along the travel path and stop at a designated loading position, based on travel path data and position data of the dump truck, wherein the travel path is the driving path of the dump truck and terminates at the designated loading position, the designated loading position being a position specified as the location where a loading machine loads goods into the dump truck's cargo bed, the control system for the dump truck being characterized in that... The loading machinery's operating device includes a boom, a stick, and attachments. The operating plane of the operating device is a plane passing through the center of the operating device in the left-right direction, and in which the boom, the stick, and the attachments can all move. The control device calculates a first stopping direction based on the data from the travel path. This first stopping direction is the forward / backward direction of the dump truck when it travels along the travel path and stops at the designated loading position. Furthermore, based on the position data of the loading machinery and the designated loading position, the control device calculates the operational plane of the loading machinery's working device when the loading machinery loads goods onto the dump truck at the designated loading position. Furthermore, the control device, based on the angle between the operating plane of the working device and the first stopping direction, and the distance between the first and second rear wheels of the dump truck (i.e., the distance between the rear wheels), corrects the driving path in a manner that aligns the second stopping direction with the operating plane of the working device, and calculates the corrected driving path. The corrected driving path is a driving path that has been modified and ends at the designated loading position. The second stopping direction is the forward and backward direction of the dump truck when it reverses on the corrected driving path and stops at the designated loading position.

2. The control system for the dump truck according to claim 1, characterized in that, The control device corrects the driving path and calculates the corrected driving path based on the angle between the operating plane of the working device and the first stopping direction, and the distance between the first and second rear wheels located on the left and right sides of the dump truck, i.e., the distance between the rear wheels, in a way that makes the angle between the second stopping direction and the operating plane of the working device close to zero.

3. The control system for the dump truck according to claim 1, characterized in that, The position data of the loading machinery is the position data of the rotation center of the loading machinery.

4. The control system for the dump truck according to claim 1, characterized in that, The control device calculates a first distance, which is the distance between the first position and the second position in the first stopping direction, based on the distance between the rear wheels and the angle formed by the first stopping direction and the operating plane of the working device. The first position is the position of the first rear wheel when the dump truck is traveling on the driving path and stops at the designated loading position; the second position is the position of the first rear wheel when the dump truck is traveling on the corrected driving path and stops at the designated loading position. Furthermore, the control device calculates a second distance, which is the distance between the first position and the second position in a direction orthogonal to the first stop direction, based on the distance between the rear wheels and the angle formed by the first stopping direction and the operating plane of the working device. Furthermore, the control device calculates a first point on the travel path that is a distance away from the designated loading position from the first point, a second point on the travel path that is a further distance away from the first point from the first point, and a third point on the travel path that is a further distance away from the second point from the second point. Furthermore, the control device causes the driving path between the first point and the second point to be moved parallel to the second distance in a direction orthogonal to the first stopping direction, and calculates the path that can connect the parallel-moved path with the third point and the loading designated position as the corrected driving path.

5. The control system for the dump truck according to claim 1, characterized in that, It also has an obstacle sensor that detects obstacles present in the direction of travel of the dump truck. The control device determines whether the dump truck will come into contact with the obstacle detected by the obstacle sensor when it travels on the corrected travel path, based on the distance between the obstacle detected by the obstacle sensor and the corrected travel path during the initial travel of the dump truck. If it is determined that the dump truck will come into contact with an obstacle detected by the obstacle sensor, a control signal is output to control the dump truck in a manner that causes the dump truck to travel on the driving path.

6. The control system for the dump truck according to claim 1, characterized in that, It also has an obstacle sensor that detects obstacles present in the direction of travel of the dump truck. The control device determines whether the dump truck will come into contact with an obstacle detected by the obstacle sensor while traveling on the corrected travel path, based on the distance between the obstacle detected by the obstacle sensor and the corrected travel path. If it is determined that the dump truck will come into contact with an obstacle detected by the obstacle sensor, a control signal is output to control the dump truck in a manner that causes the dump truck to travel on the driving path.

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