WO2023113005A1

WO2023113005A1 - Mining machine and autonomous travel system

Info

Publication number: WO2023113005A1
Application number: PCT/JP2022/046315
Authority: WO
Inventors: 幹雄板東; 信一魚津; 朋之 ▲濱▼田; 大基手塚
Original assignee: 日立建機株式会社
Priority date: 2021-12-17
Filing date: 2022-12-16
Publication date: 2023-06-22
Also published as: JP2023090308A

Abstract

A front external sensor 9, a left side external sensor 10, a right side external sensor 11, and a rear external sensor 12 are attached to a mining machine 1 that travels autonomously in a mine. A stopping-possible range of the mining machine 1 is configured using maximum reachable regions 604, 605 of the mining machine 1 at the time of maximum braking that are calculated on the basis of the relationship between a preset speed range and maximum steering angle, static unenterable-by-turning regions 606 that the mining machine 1 cannot enter when the mining machine 1 has turned at the maximum steering angle, and line segments 608 that are parallel to the direction of a vehicle body 2 and connect the static unenterable-by-turning regions 606 and endpoints 607 of the maximum reachable region 604. The front external sensor 9, the left side external sensor 10, the right side external sensor 11, and the rear external sensor 12 are positioned such that the detection ranges thereof include the stopping-possible range.

Description

Mining equipment and autonomous driving systems

The present invention relates to mining machines and autonomous driving systems.

A dump truck, for example, is known as a mining machine that autonomously travels through a mine without an operator on board. In such a dump truck, external sensors such as Radar, LiDAR, and cameras are used instead of the operator's eyes to drive while grasping road conditions and obstacles. Then, when a bad road surface or an obstacle is detected via an external sensor, the dump truck appropriately performs actions such as detour, avoidance, and stop to ensure safety of travel.

In addition, mining equipment differs greatly in terms of the objects to be detected and the detection range from general passenger cars. In particular, mining equipment has a much larger body (specifically, a larger width and height) than a passenger car, so an external sensor detects a wide range of surrounding rough road surfaces or obstacles. There is a need.

Since the number of attachment points for external sensors is limited, the size of the detection range and resolution are in conflict with each other. Therefore, in a mining machine having a large vehicle body, a plurality of external sensors are used to detect the surroundings of the vehicle, as disclosed in Patent Document 1 below, for example, in order to widen the detection range while ensuring resolution.

Patent No. 5667594

However, by using many external sensors, not only the external sensors themselves fail, but also dust and dirt adhere to the external sensors, affecting the normal functioning of the external sensors and increasing the failure rate of the system. Resulting in. On the other hand, this is not a big problem for mining machines that are operated by an operator, but for unmanned mining machines that run autonomously, if the external sensor becomes unusable, autonomous running will be forced to stop, which will reduce productivity. I invite you. Therefore, it is desirable to minimize the number of external sensors. However, if the number of external sensors is reduced, there is a possibility of collision with an undetected obstacle or the like, and the number of external sensors cannot be simply reduced.

The present invention was made to solve such technical problems, and aims to provide a mining machine and an autonomous driving system that can realize safe driving with the minimum necessary external sensors.

A mining machine according to the present invention comprises a pair of steerable front wheels arranged on both left and right sides of a vehicle body and a pair of rear wheels arranged on both left and right sides of the vehicle body, and autonomously travels in a mine. The mining machine is equipped with a plurality of external sensors for detecting road surface conditions and obstacles in front, sides, and rear of the mining machine, and is obtained based on the relationship between a preset speed range and the maximum steering angle. A maximum reachable area of the mining machine during maximum braking, a steady turning impenetrable area that the mining machine cannot enter when the mining machine turns at a maximum steering angle, and the maximum reachable area parallel to the direction of the vehicle body. and a line segment connecting the end point of and the steady turning inviolable area, a stoppable range of the mining machine is set, and the plurality of external sensors are arranged so that a detection range includes the stoppable range. is characterized by

In the mining machine according to the present invention, the maximum reaching range of the mining machine at the time of maximum braking, which is obtained based on the relationship between the preset speed range and the maximum steering angle, and the and a line segment parallel to the direction of the vehicle body and connecting an end point of the maximum reachable area and the steady turning impenetrable area defines a stoppable range of the mining machine. The external sensors for detecting road surface conditions and obstacles in front, sides and rear of the mining machine are arranged so that the detection range includes the stop possible range. In this way, by attaching external sensors to the front, sides, and rear of the mining machine so as to cover the minimum detection range necessary for safe driving, safe driving can be achieved with the minimum necessary external sensors. can do.

According to the present invention, safe driving can be achieved with the minimum number of external sensors.

1 is a side view showing a schematic configuration of a mining machine according to an embodiment; FIG. 1 is a block configuration diagram showing a mining machine according to an embodiment; FIG. 4 is a table showing the relationship between the speed range of mining equipment and the maximum steering angle; 4 is a flow chart showing processing for determining a stoppable range of the mining machine. FIG. 4 is a plan view for explaining the steering angle, center-of-gravity position, and orientation of the mining machine; FIG. 4 is a plan view for explaining reaching points until the mining machine stops; It is a figure for demonstrating the maximum reachable area of a mining machine. It is a figure for demonstrating the steady-state turning inviolable area of a mining machine. FIG. 4 is a diagram for explaining a stoppable range of the mining machine and mounting positions of external sensors; 4 is a flowchart showing travel processing of the mining machine; 4 is a flow chart showing collision determination processing of a mining machine; It is a figure for demonstrating a run-permitted area. 1 is a block configuration diagram showing an autonomous driving system according to an embodiment; FIG. 4 is a flowchart showing travel processing of the mining machine in the autonomous travel system. It is a flowchart which shows the collision determination process of the mining machine in an autonomous driving system.

An embodiment of a mining machine and an autonomous traveling system according to the present invention will be described below with reference to the drawings. In the description of the drawings, the same elements are denoted by the same reference numerals, and redundant description thereof will be omitted. Also, in the following description, the vertical, horizontal, front and rear directions and positions are based on the mining machine. Furthermore, in the following description, an example of a dump truck in which an operator does not board is given as a mining machine, but the present invention is not limited to a dump truck.

[About mining equipment]
FIG. 1 is a side view showing a schematic configuration of the mining machine according to the embodiment, and FIG. 2 is a block configuration diagram showing the mining machine according to the embodiment. A mining machine 1 is a dump truck capable of autonomously traveling in a mine, and includes a vehicle body 2, a pair of left and right front wheels 3 arranged on the front side of the vehicle body 2, and a pair of left and right rear wheels 4 arranged on the rear side of the vehicle body 2. and a loading platform 5 supported on the vehicle body 2 so as to be able to rise and fall. The vehicle body 2 is composed of, for example, a sturdy metal frame member, and is connected to the wheel axles by springs or the like. The front wheels 3 are steerable driven wheels and the rear wheels 4 are non-steerable drive wheels. The loading platform 5 is connected to the vehicle body 2 via an elevating cylinder 6 .

The mining machine 1 also has a plurality of GNSS (Global Navigation Satellite System) antennas 7 for receiving radio waves from positioning satellites such as GPS (Global Positioning System), and a GNSS antenna 7 based on the radio waves received by the GNSS antenna 7. and a GNSS receiver 8 for measuring the terrestrial position (eg latitude, longitude, altitude) of. The GNSS receiver 8 is connected to a control device 20 (described later) via a CAN (Controller Area Network), and outputs measurement results to the control device 20 .

In addition, the mining machine 1 is equipped with a plurality (here, four) of external sensors for detecting road surface conditions and obstacles in front, sides, and rear of the mining machine 1 . Specifically, a front external sensor 9 is provided on the front surface of the mining machine 1, a left external sensor 10 is provided on the left side of the mining machine 1, a right external sensor 11 is provided on the right side of the mining machine 1, and a rear external sensor 11 is provided on the rear of the mining machine 1. A rear external sensor 12 is attached to each.

As shown in FIG. 1 and later-described FIG. 9, the front external sensor 9 detects the road surface condition and obstacles in front of the mining machine 1, and the left external sensor 10 detects the road surface condition from the front of the front wheel 3 to the left. The right side external sensor 11 detects road conditions and obstacles from the front to the right side of the front wheels 3, and the rear external sensor 12 detects road conditions and obstacles behind the rear wheels 4. . These external sensors are each connected to the control device 20 via CAN, and output detection results to the control device 20 .

Furthermore, the mining machine 1 is provided with an inertial measurement sensor (IMU: Inertial Measurement Unit) 13 that measures the acceleration and angular velocity of the mining machine 1 and a control device 20 . The IMU 13 is connected to the control device 20 via CAN and outputs measurement results to the control device 20 . Moreover, although not shown, the mining machine 1 may further include a speed sensor for detecting the speed of the mining machine 1 .

The control device 20 performs overall vehicle control of the mining machine 1 . The control device 20 includes, for example, a CPU (Central Processing Unit) that executes calculations, a ROM (Read Only Memory) as a secondary storage unit that records programs for calculations, and storage of calculation progress and temporary control variables It is composed of a microcomputer that is combined with a RAM (Random Access Memory) as a temporary storage unit that stores , and performs various controls related to the running and operation of the mining machine 1 by executing the stored program.

As shown in FIG. 2 , the control device 20 includes a position/orientation estimation unit 21, a route setting unit 22, a route following control unit 23, a road unevenness obstacle detection unit 24, a collision determination unit 25, and a storage unit 26. and

The position/orientation estimation unit 21 estimates the position of the mining machine 1 based on the measurement results of the GNSS receiver 8 and also estimates the orientation of the mining machine 1 based on the measurement results of the IMU 13 . The position/orientation estimation unit 21 outputs the estimated results to the route setting unit 22, the route following control unit 23, the road unevenness obstacle detection unit 24, the collision determination unit 25, and the storage unit 26, respectively.

The route setting unit 22 sets the travel route of the mining machine 1 based on the map data stored in the map database (map DB) 27. The route setting unit 22 outputs the set travel route to the route following control unit 23 and the collision determination unit 25, respectively. In addition to map information, the map DB 27 also includes information defining travel speeds and the like.

The route following control unit 23 controls the steering and travel speed of the mining machine 1 so that the travel route set by the route setting unit 22 can be followed. Specifically, the route follow-up control unit 23 outputs a steering angle command to the front wheels 3 and a speed command to the rear wheels 4 so that the set travel route can be followed.

The road surface unevenness obstacle detection unit 24 detects road surface unevenness and obstacles on the road surface around the mining machine 1 based on the detection results of the front external sensor 9, the left external sensor 10, the right external sensor 11, and the rear external sensor 12. Detect objects. Already well-known techniques can be used to detect road surface unevenness and obstacles. For example, the road surface irregularity obstacle detection unit 24 selects a plane that has many points that are fitted to the plane from the point group obtained from the external sensor and sets it as the road surface on which the vehicle is traveling, and the height of the road surface is equal to or higher than a certain threshold. Detect points as obstacles. The detected obstacle points are grouped, and the distance of the point with the maximum distance from the road surface among the grouped points is calculated by calculating the height of the obstacle and the average position of the grouped points. Calculated as the position of an object. Also, if the obstacle is widely distributed, the radius of the circle containing all the grouped points centered on the position of the obstacle is calculated to represent the extent of the obstacle.

The collision determination unit 25 determines the position of the mining machine 1 estimated by the position/orientation estimation unit 21, the travel route set by the route setting unit 22, the road unevenness position and the obstacle position stored in the storage unit 26. A collision determination is performed based on and. Also, the collision determination unit 25 sets a collision determination flag based on the result of the collision determination, and outputs the flag to the route follow-up control unit 23 .

The storage unit 26 stores data and information related to each control process of the control device 20 as a whole. For example, the storage unit 26 stores the position and orientation of the mining machine 1 estimated by the position/orientation estimation unit 21, and the road surface unevenness and obstacles detected by the road surface unevenness obstacle detection unit 24, respectively.

Here, the mounting positions of the external sensors attached to the mining machine 1 will be explained.

Objects to be detected via the external sensor are obstacles around the mining machine 1 and unevenness of the road surface. Typical external sensors are LiDAR (Light Detection and Ranging), which measures the distance to the target from the reflection of laser light and treats a large number of measurement points as a point group, cameras, or Radar, but here LiDAR is taken as an example. . When an external sensor detects an obstacle and unevenness of the road surface around the mining machine 1, the mining machine 1 takes an avoidance action such as a stop or a detour. In particular, when safety is taken into consideration, it is a minimum requirement that the mining machine can stop without colliding with an obstacle while traveling, and detection of obstacles is based on the premise that the mining machine covers a range in which it can stop.

The stoppable range of the mining machine (hereinafter referred to as "stoppable range") differs depending on whether the mining machine is operated by the operator or when the mining machine is autonomously traveling. . In order to realize safe driving, the route following control unit 23 limits the maximum value of the steering angle in each driving speed range. Note that the maximum value of the steering angle is a design value determined in advance according to the type of mining machine 1 .

FIG. 3 is a table showing the relationship between the speed range of the mining machine and the maximum steering angle. In FIG. 3, the magnitude of the numerical value is V ₀ <V _m , the speed range has a larger value as the subscript increases, and the maximum steering angle decreases as the speed range increases, and the relationship S ₁ >S _m is satisfied. be. Both numerical values are assumed to be positive values. In such a table, the initial speed of the mining machine is divided at regular intervals from the maximum speed (V _m ) on the specification of the mining machine to the minimum speed (V ₀ ) that can be controlled by the path following control unit 23 . 3 is an example of division into m. Using this table, the stoppable range of the mining machine 1 can be determined by calculating the reaching range of the mining machine 1 when the mining machine 1 decelerates at the maximum deceleration in the specification from each speed range.

Next, the processing for determining the stoppable range of the mining machine will be explained using FIG. The determination processing shown in FIG. 4 is performed by the control device 20 .

First, in step S101, the control device 20 selects one speed range from the table showing the relationship between the speed range and the maximum steering angle shown in FIG. Since all speed ranges are finally selected, the order of selection may be in ascending order or in ascending order. In step S102 following step S101, the control device 20 divides the maximum steering angle corresponding to the speed range selected in step S101 by m. In step S103 following step S102, the control device 20 selects one steering angle from the steering angles divided into m equal parts. Since all steering angles are finally selected, the order of selection may be in ascending order or in ascending order of steering angles.

In step S104 following step S103, the control device 20 calculates the position of the center of gravity and the orientation of the mining machine 1 when the mining machine 1 is stopped (that is, during maximum braking). Specifically, as shown in FIG. 5, the control device 20 sets the maximum speed V of the speed range selected in step S101 and the steering angle δ The center of gravity position 601 and the azimuth of the mining machine 1 when the mining machine 1 is stopped are calculated when the mining machine 1 decelerates. FIG. 5 shows the steering angle, the position of the center of gravity and the azimuth when the mining machine 1 is viewed from above. Here, it is assumed that the position of the center of gravity 601 is set at one point on the vehicle body 2 in advance, and that the steering angle δ does not change during deceleration.

The calculation method differs depending on the type of mining equipment and the required accuracy, but in the case of dump trucks, for example, it can be calculated using the following formulas (1) to (4) using a calculation method based on Ackermann steering geometry.

In equations (1) to (4), V is the velocity of the mining machine 1 at time t, θ is the orientation of the mining machine 1 at time t, and X and Y are the coordinates of the center of gravity position 601 at time t. Also, α is the deceleration of the mining machine 1, δ is the steering angle, and l is the wheelbase, that is, the distance from the center of the front wheel shaft to the center of the rear wheel shaft. _lr indicates the distance from the center of gravity position 601 to the center of the rear wheel axle. Calculations based on formulas (1) to (4) are repeated until the speed of the mining machine 1 becomes 0 (that is, until it stops).

In step S105 following step S104, the control device 20 determines the reaching point until the mining machine 1 stops (hereinafter referred to as " ) is calculated and stored. FIG. 6 is a plan view for explaining reaching points until the mining machine stops. FIG. 6 shows the reaching points to stop when the mining machine 1 turns to the left while moving forward or backward, 602 indicates the position of the front end of the mining machine 1 when moving forward, and 603 when moving backward. 2 shows the position of the rear end of the mining machine 1 in the case of FIG. It should be noted that the same applies when the turning direction is to the right, so redundant description will be omitted. A vector d _f from the center of gravity position 601 to the front end 602 when the mining machine 1 moves forward (see FIG. 5), and a vector _dr from the center of gravity position 601 to the rear end 603 when the mining machine 1 moves backward (see FIG. 5). can be calculated by the following formulas (5) and (6). Note that "*" in equations (5) and (6) is f for forward travel and r for backward travel.

When the coordinates (x, y) of the position of the reaching point until the mining machine 1 stops are calculated using equations (5) and (6), the position of the reaching point until the mining machine 1 stops is obtained. Then, the control device 20 causes the storage unit 26 to store the obtained position of the reaching point until the mining machine 1 stops.

In step S106 following step S105, the control device 20 determines whether or not all m-divided steering angles have been selected. If it is determined that all steering angles have not been selected (in other words, steering angles remain to be selected), the determination process returns to step S103, and the processes of steps S103 to S105 are repeated. On the other hand, if it is determined that all steering angles have been selected, the determination process proceeds to step S107.

In step S107, the control device 20 determines whether or not all speed ranges have been selected. If it is determined that all speed ranges have not been selected (in other words, some speed ranges remain to be selected), the determination process returns to step S101, and steps S101 to S106 are repeated. On the other hand, if it is determined that all speed ranges have been selected, the determination process proceeds to step S108.

In step S108, the control device 20 obtains the maximum reachable area of the mining machine 1 based on the reaching point until the mining machine 1 stops stored in step S105. FIG. 7 is a diagram for explaining the maximum reachable area of the mining machine. In FIG. 7, 604 denotes the maximum front reachable area of the

mining machine

1, and 605 denotes the maximum rearward reachable area of the mining machine 1, respectively. The front maximum reach 604 is a line segment obtained by connecting all the front ends of the reach points stored in the storage unit 26 where x is positive, and the rear maximum reach 605 is stored in the storage unit 26. It is a line segment obtained by connecting all the rear ends of each reaching point where x is negative. In this embodiment, since the steering angle is limited to a positive value, the maximum reachable area of the mining machine 1 can be obtained by a bilaterally symmetrical method with respect to the axle.

　In step S109 following step S108, the control device 20 obtains a steady turning inviolable area. FIG. 8 is a diagram for explaining the steady turning impenetrable area of the mining machine. In FIG. 8, 604 is the front maximum reachable area obtained by the left-right symmetrical method as described above, and 605 is the rearward maximum reachable area obtained by the left-right symmetrical method. In the present embodiment, the steady turning impenetrable area means an area into which the mining machine 1 cannot enter when the mining machine 1 turns at the maximum steering angle, and is obtained as follows.

First, when the mining machine 1 makes a steady turn, it is possible to calculate the trajectory that the mining machine 1 passes when turning at the maximum steering angle, based on the minimum turning radius in the specification according to the type of the mining machine 1. be. A dashed line 606 in FIG. 8 indicates a steady turning inviolable area of the mining machine 1, which is an area inside a circle that is a trajectory along which the mining machine 1 passes. This area is an area that can never be entered unless the mining machine 1 performs a special operation such as turning back. That is, when the mining machine 1 is intended to prevent a collision with a stationary object, this area does not need to be detected using an external sensor or the like. Therefore, for example, when an obstacle detected by the left-side external sensor 10 exists within the steady turning impenetrable area, the control device 20 excludes the detected obstacle from the target obstacles related to the process of stopping the mining machine 1. can control the running of the mining machine 1. By excluding obstacles in the intrusive area in this manner, the control processing speed can be increased.

Then, when the left steady turning impenetrable area 606 is obtained, the right steady turning impenetrable area 606 can also be obtained by a symmetrical method.

In step S110 subsequent to step S109, the control device 20 connects the forward maximum reachable area 604 obtained in step S108 and the steady turning impenetrable area 606 obtained in step S109 with a line segment, and adopts a symmetrical method with respect to the axle. is used to set the stoppable range of the mining machine 1 .

Specifically, as shown in FIG. 9 , starting from an end point 607 of the front maximum reach area 604, a line segment 608 parallel to the direction of the vehicle body 2 and connecting the end point 607 and the steady turning impenetrable area 606 is drawn, A point 609 is a point where the line segment 608 intersects the steady turning non-aggression area 606 . The stoppable range of the mining machine 1 is set by the front maximum reachable area 604 , the line segment 608 , the steady turning impenetrable area 606 and the rearward maximum reachable area 605 .

In addition, in FIG. 9, 610 is the end point of the rearward maximum reachable area 605, and also the intersection of the rearward maximum reachable area 605 and the steady turning impenetrable area 606. Since the line segment connecting the

endpoints

609 and 610 is inside the stationary turning impenetrable region 606, the stoppable range of the mining machine 1 does not exist between the

endpoints

609 and 610, and the stationary pivoting impenetrable region does not exist. A zone 606 separates the anterior and posterior sides. Therefore, between the

endpoints

609 and 610, it is not necessary to detect road surface conditions and obstacles via an external sensor or the like.

Therefore, for example, when the left side external sensor 10 and the right side external sensor 11 arranged on the side of the mining machine 1 have an undetectable range, and the undetectable range is within the steady turning unaggressive area 606, the control device 20 allows the mining machine 1 to continue running without making it an error. In this way, the mining machine 1 can be prevented from being stopped unnecessarily, so a decrease in the work efficiency of the mining machine 1 can be suppressed.

When the stoppable range of the mining machine 1 is set as described above, it is preferable to arrange the external sensors based on the stoppable range of the mining machine 1 . For example, by adjusting the position and attitude of the external sensor so that the detection range of the external sensor includes the stoppable range, at least when a stationary obstacle is detected, a collision can be avoided by an emergency stop.

Specifically, as shown in FIG. 9, the front maximum reachable area 604 is covered by the front external world sensor 9, the left side external field sensor 10, and the right side external field sensor 11, and the rear maximum reachable area 605 is covered by the rear external field sensor 12. do. The front external sensor 9 is attached to the center of the front surface of the mining machine 1, and detects a plane (road surface) on which the mining machine exists, including at least the maximum distance L1 to the front maximum reach area 604 and the maximum width L2 of the front maximum reach area 604. Its placement height and depression angle are adjusted to cover.

Further, the left side external sensor 10 and the right side external sensor 11 are mounted on the left and right sides of the vehicle body 2 directly above the front wheel axle or on the front side of the front wheel axle, and have a detection range including at least a line segment 608. partly overlaps with the detection range of Since the detection range of the left side external sensor 10 and the right side external sensor 11 and the detection range of the front external sensor 9 partially overlap in this way, it is possible to prevent leakage of the required detection range.

The rear external sensor 12 is attached to the center of the vehicle body 2 on the rear side of the rear wheel axle, and its placement height and depression angle are adjusted so as to cover the maximum rear reaching area 605 .

The traveling process of the mining machine 1 equipped with the external sensors arranged as described above will be described below with reference to FIG. FIG. 10 is a flow chart showing travel processing of the mining machine. The traveling process shown in FIG. 10 depends on the cycle of the control process of the mining machine 1, and is repeatedly executed, for example, once every 10 milliseconds.

First, in step S<b>201 , the position/orientation estimation unit 21 estimates the position and orientation of the mining machine 1 based on the measurement results of the GNSS receiver 8 and the measurement results of the IMU 13 . In step S<b>202 following step S<b>201 , the route setting unit 22 sets the travel route of the mining machine 1 . At this time, the route setting unit 22 sets the travel route using the map DB 27 based on the preset destination and the position of the mining machine estimated in step S201.

In step S203 following step S202, the control device 20 determines whether the mining machine 1 has started traveling along the set travel route. If it is determined that the vehicle has started traveling on the travel route, the travel process proceeds to step S206. On the other hand, when it is determined that the vehicle has not started traveling on the travel route, the travel processing proceeds to step S204.

In step S204, since the mining machine 1 has not yet started running, the control device 20 determines whether or not the current position of the mining machine 1 is within the inspection completed area. The inspection completed area is an area where the road surface condition is good and there are no obstacles. This inspection completed area is set in the map DB 27, and is an area where it has been confirmed that there are no obstacles or uneven road surfaces within the inspection completed area, and that there are no moving objects such as other mining machines or people. .

Then, when it is determined that the current position of the mining machine 1 is within the inspection completion area, the mining machine 1 starts traveling (see step S205). After step S205 ends, the traveling process proceeds to step S206. On the other hand, if it is determined that the current position is outside the inspection completed area, the travel process ends.

In step S206, the road surface unevenness obstacle detection unit 24 detects road surface unevenness around the mining machine 1 and Detect obstacles.

In step S207 following step S206, the control device 20 causes the storage unit 26 to store information on road unevenness and obstacles detected in step S206. At this time, the storage unit 26 assigns an ID to each of the unevenness of the road surface detected in step S206, the position and height of the obstacle, the extent of the obstacle, and the like, and stores them.

In step S208 following step S207, the collision determination unit 25 uses the road surface unevenness and obstacle information detected by the external sensor and stored in the storage unit 26 to determine a collision. Collision determination will be described in detail below with an example of an obstacle based on FIG. 11 .

FIG. 11 is a flowchart showing collision determination processing for mining machines. First, in step S208-1, the collision determination unit 25 acquires the travel route and travel-permitted section of the mining machine 1 set in step S202. As shown in FIG. 12, a travel route 700 is composed of a plurality of nodes (eg, nodes 701) arranged at predetermined intervals and links (eg, links 702) connecting the nodes. These nodes are data indicating coordinates on the travel route 700 .

The travel-permitted section 705 is an area obtained by dividing the travel route 700. Only one mining machine 1 is allowed to travel in one travel-permitted section 705, and autonomous travel is realized in which the mining machines 1 do not interfere with each other. A travel-permitted section 705 is formed by a start node 703 , an end node 704 , and width regulation line segments 706 on both left and right sides that determine the width of the travel route 700 . The mining machine 1 autonomously travels so as not to deviate from the travel-permitted section 705 .

In step S208-2 following step S208-1, the collision determination unit 25 determines whether or not there is an obstacle detected by the external sensor and stored in the storage unit 26 around the aircraft. At this time, the collision determination unit 25 calculates the distance from the mining machine 1 to the obstacle based on the position of the mining machine 1 estimated in step S201 and the position of the obstacle stored in the storage unit 26, The calculated distance is compared with a preset threshold. If the calculated distance is equal to or less than the threshold, the collision determination unit 25 determines that there is an obstacle around the aircraft. Accordingly, the collision determination process proceeds to step S208-3.

On the other hand, if the calculated distance is greater than the threshold, the collision determination unit 25 determines that there are no obstacles around the aircraft. Accordingly, the collision determination process proceeds to step S208-7. In step S208-7, the collision determination unit 25 sets the collision determination flag to "0" (meaning that there is no object with the possibility of collision).

In step S208-3, the collision determination unit 25 determines whether or not the height of the obstacle is equal to or greater than a preset threshold. At this time, the collision determination unit 25 acquires the height of the obstacle from the storage unit 26 based on the ID of the obstacle determined to be in the vicinity of the aircraft, and uses the acquired height of the obstacle as a threshold value. compare. If it is determined that the height of the obstacle is not equal to or greater than the threshold, the collision determination process proceeds to step S208-7. On the other hand, if it is determined that the height of the obstacle is equal to or greater than the threshold, the collision determination process proceeds to step S208-4.

In step S208-4, the collision determination unit 25 determines whether or not the position of the obstacle is within the steady turning impenetrable area. At this time, the collision determination unit 25 first acquires the position and extent of the obstacle from the storage unit 26 based on the ID of the obstacle whose height is equal to or greater than the threshold. Next, the collision determination unit 25 determines whether the acquired position and extent of the obstacle are within the above-described steady turning impenetrable area 606 . If the position and extent of the obstacle is partially or wholly within the circle represented as the steady turning impenetrable area 606 , it is determined that the obstacle is within the steady turning impenetrable area 606 . Accordingly, the collision determination process proceeds to step S208-7.

On the other hand, if the position or extent of the obstacle does not fall within the circle represented by the steady turning impenetrable area 606, the obstacle is not within the steady turning impenetrable area 606 (in other words, the steady turning impenetrable area 606). Accordingly, the collision determination process proceeds to step S208-5. With this processing, even if the external sensor is soiled or partly undetectable due to dust or the like, if the undetectable range is within the steady turning impenetrable area 606, the external sensor is detected. It is possible to continue running the mining machine 1 without being judged to be out of order. Therefore, it is possible to suppress the deterioration of the working efficiency of the mining machine 1 .

At step S208-5, the collision determination unit 25 determines whether or not the position of the obstacle is within the travel route and the travel-permitted section. At this time, the collision determination unit 25 determines that the position and extent of the obstacle determined to exist outside the steady turning impenetrable area 606 is the travel route 700 and the travel-permitted section obtained in step S208-1. 705 is determined. Since the travel-permitted section 705 is represented by a rectangle or a polygon, when the position of the obstacle and part or all of the extent of the obstacle are included inside it, the position of the obstacle is within the travel route and the travel-permitted section. It is determined that there is Accordingly, the collision determination process proceeds to step S208-6.

On the other hand, if the position of the obstacle and part or all of the extent of the obstacle are not included in the travel-permitted section 705, it is determined that the position of the obstacle is not within the travel route and the travel-permitted section. Accordingly, the collision determination process proceeds to step S208-7.

At step S208-6, the collision determination unit 25 sets the collision determination flag to "1" (meaning that there is an object with the possibility of collision). This completes the collision determination process in step S208.

Then, in step S209 following step S208 shown in FIG. 10, the route following control unit 23 determines whether or not there is a collision. At this time, the route follow-up control unit 23 receives the collision determination flag from the collision determination unit 25, and determines that there is a collision when the collision determination flag is "1". Accordingly, the traveling process proceeds to step S210. On the other hand, when the collision determination flag is "0", the route following control unit 23 determines that there is no collision. Accordingly, the traveling process proceeds to step S211.

In step S210, since the collision determination flag is "1", the route follow-up control unit 23 performs processing to stop the mining machine 1. At this time, the route following control unit 23 calculates the distance based on the position of the road unevenness or the obstacle and the position of the own aircraft, determines the deceleration, and outputs a deceleration command to the rear wheels 4 to stop the vehicle. . This initiates deceleration of the mining machine 1 .

At step S211 following step S210, the control device 20 determines whether or not the position of the own machine is positioned at the end of the travel route. When it is determined that the own aircraft is not positioned at the end of the travel route, the travel processing returns to step S201. On the other hand, when it is determined that the vehicle is positioned at the end of the travel route, a series of travel processing ends.

Through this series of traveling processes, the mining machine 1 uses the front external sensor 9, the left external sensor 10, the right external sensor 11, and the rear external sensor 12 to avoid obstacles and the like when autonomously traveling in the mine. It is possible to avoid collisions and realize safe driving.

In the mining machine 1 configured as described above, the

maximum reach areas

604 and 605 of the mining machine 1 at the time of maximum braking, which are obtained based on the relationship between the preset speed range and the maximum steering angle, and the A steady turning impenetrable area 606 into which the mining machine 1 cannot enter when turning at the maximum steering angle, and a line segment parallel to the direction of the vehicle body 2 and connecting an end point 607 of the front maximum reaching area 604 and the steady turning impenetrable area 606. 608 sets the stoppable range of the mining machine 1, and the front external sensor 9, the left external sensor 10, the right external sensor 11, and the rear external sensor 12 are arranged so that the detection range includes the stoppable range. . In this way, the front external sensor 9, the left external sensor 10, the right external sensor 11, and the rear external sensor 12 can be attached to the mining machine 1 so as to cover the minimum detection range required for safe driving. Therefore, it is possible to realize safe driving with the minimum required number of external sensors.

[About Autonomous Driving System]
The autonomous driving system will be described below with reference to FIGS. 13 to 15. FIG.

FIG. 13 is a block configuration diagram showing an autonomous driving system according to the embodiment. The autonomous traveling system 100 of this embodiment includes a plurality of mining machines 1A and a control station 30 configured to be able to communicate with each mining machine 1A and to manage these mining machines 1A.

The mining machine 1A is different from the mining machine 1 described above in that it does not set the travel route by itself, but acquires the travel route from the control station 30 . Since other configurations are the same as those of the mining machine 1 described above, redundant description will be omitted.

Therefore, the mining machine 1A does not include the route setting section 22 and the map DB 27, but further includes the speed sensor 14 and the communication device 15. The speed sensor 14 detects the running speed of the mining machine 1 and outputs the detection result to the position/orientation estimation unit 21 . The communication device 15 is, for example, a wireless device, and is connected to the storage section 26 of the control device 20 .

The mining machine 1A transmits and receives information to and from the control station 30 via the communication device 15. The mining machine 1A transmits, for example, the position, attitude, and speed of its own machine to the control station 30, and the control station 30 receives the positions, attitudes, and speeds of other mining machines (hereinafter referred to as "other machines") existing around its own machine. Get speed. Further, the mining machine 1A requests the control station 30 for its travel route, and acquires its own travel route from the control station 30 .

On the other hand, the control station 30 includes, for example, a CPU (Central Processing Unit) that executes calculations, a ROM (Read Only Memory) as a secondary storage unit that records programs for calculations, and storage of the progress of calculations and temporary It is composed of a microcomputer combined with a RAM (random access memory) as a temporary storage unit that stores control variables, and performs each control related to management of all the mining machines 1A by executing the stored program. For example, in response to a route request from an arbitrary mining machine 1A in the mine, the control station 30 transmits the traveling route of the mining machine 1A that has requested the route, and also the position, posture, and position of other machines existing in the vicinity. The speed and the like are also transmitted to the mining machine 1A that requested the route.

The control station 30 includes a communication device 31 that communicates with the mining machines 1A, a route planning section 32 that plans and creates travel routes for each mining machine 1A, and a map DB 33.

　Fig. 14 is a flow chart showing the traveling process of the mining machine in the autonomous traveling system. The traveling process shown in FIG. 14 depends on the cycle of the control process of the mining machine 1A, and is repeatedly executed, for example, once every 10 milliseconds.

First, in step S301, the position and orientation estimation unit 21 of the mining machine 1A estimates the position and orientation of the mining machine 1 based on the measurement results of the GNSS receiver 8 and the measurement results of the IMU 13, and estimates the position and orientation of the mining machine 1A. is transmitted to the control station 30 via the communication device 15 . At this time, the position/orientation estimation unit 21 may also transmit the speed of its own device. The control station 30 broadcasts the position and attitude transmitted from each mining machine 1A with an ID.

In step S302 following step S301, the mining machine 1A requests the control station 30 for its own traveling route, and acquires its own traveling route from the control station 30. When requesting the travel route of the mining machine 1A to the control station 30, the mining machine 1A also transmits the ID of the machine itself. Upon receiving the route request, the control station 30 creates and transmits the travel route of the requested mining machine 1A.

Specifically, based on the ID of the mining machine 1A in the route request, the route planning unit 32 uses the preset destination, the map information stored in the map DB 33, and the positions of other machines in the vicinity. planning and creating the optimal driving route. The route planning unit 32 transmits the created travel route via the communication device 31 to the mining machine 1A that requested the route. When the travel route is received, the mining machine 1A causes the storage unit 26 to store the received travel route.

Steps S303 to S307 are the same as steps S203 to S207 (see FIG. 10) described above, so redundant description will be omitted.

In step S308 following step S307, the mining machine 1A acquires other machine information and calculates the stoppable distance. The other aircraft information includes the position, attitude, speed, weight, braking force, stoppable distance calculation coefficient, and the like of the other aircraft. These pieces of other aircraft information are acquired from information broadcast by the control station 30 .

The possible stopping distance can be calculated based on the following formula (7), as described in Japanese Patent No. 6325655, for example.

In equation (7), n is the number of the other aircraft, SL _n is the stopping distance of the other aircraft, v _n is the speed of the other aircraft, M _n is the weight of the other aircraft, f _n is the braking force of the other aircraft, and c _n indicates the stopping distance coefficient of other aircraft.

In step S309 following step S308, collision determination is performed. At this time, the collision determination unit 25 determines a collision using the acquired information about the other device in addition to the information about the unevenness of the road surface and the obstacles detected by the external sensor and stored in the storage unit 26 . FIG. 15 is a flowchart showing collision determination processing for mining machines in the autonomous traveling system.

Steps S309-1 to S309-7 shown in FIG. 15 are the same as steps S208-1 to S208-7 (see FIG. 11) described above, so redundant description will be omitted.

At step S309-8 following steps S309-6 and S309-7, it is determined whether or not there is another aircraft in the vicinity of the own aircraft. At this time, the collision determination unit 25 calculates the distance between the own aircraft and the other aircraft based on the position of the own aircraft and the positions of the other aircraft, and compares the calculated distance with a preset threshold value. If the distance between the own aircraft and the other aircraft is equal to or less than the threshold value, the collision determination unit 25 determines that the other aircraft exists around the own aircraft. As a result, the collision determination process proceeds to step S309-9.

On the other hand, if the distance between the own aircraft and the other aircraft is greater than the threshold, the collision determination unit 25 determines that there are no other aircraft around the own aircraft. Accordingly, the collision determination process proceeds to step S309-11.

In step S309-9, the collision determination unit 25 determines whether or not the run-permitted section of the own aircraft contacts the travel area of the other aircraft for all the other aircraft determined to be present in the vicinity of the own aircraft. . The travel area of the other aircraft is represented by a rectangle having a predetermined width given to the possible stop distance _SLn of the other aircraft calculated in step S308. Then, when there is a portion where the rectangle that is the travel-permitted section of the own aircraft and the rectangle of the travel area of the other aircraft overlap, the collision determination unit 25 determines that the travel-permitted section of the own aircraft comes in contact with the travel area of the other aircraft. do. Accordingly, the collision determination process proceeds to step S309-10. At step S309-10, the collision determination unit 25 sets the collision determination flag to "1".

On the other hand, if there is no overlap between the rectangle of the travel-permitted section of the own aircraft and the rectangle of the travel area of the other aircraft, the collision determination unit 25 determines that the travel-permitted section of the own aircraft does not contact the travel area of the other aircraft. do. Accordingly, the collision determination process proceeds to step S309-11. At step S309-11, the collision determination unit 25 maintains the already set collision determination flag. That is, for example, when the collision determination flag is set to "1" in step S309-6, the collision determination unit 25 leaves the collision determination flag "1". If the collision determination flag is set to "0" in step S309-7, the collision determination unit 25 leaves the collision determination flag "0".

Thus, the collision determination process in step S309 ends.

Steps S310 to S312 subsequent to step S309 shown in FIG. 14 are the same as steps S209 to S211 (see FIG. 10) described above, so redundant description will be omitted.

According to the autonomous traveling system 100 according to the present embodiment, when the mining machine 1A autonomously travels in the mine, the minimum necessary sensors such as the front external sensor 9, the left external sensor 10, the right external sensor 11, and the rear external sensor 12 are used. By using the external sensor, it is possible to avoid collisions with obstacles and other machines moving in the mine, and to realize safe driving.

Although the embodiments of the present invention have been described in detail above, the present invention is not limited to the above-described embodiments, and various designs can be made without departing from the spirit of the invention described in the claims. Changes can be made.

1, 1A: mining machine, 2: vehicle body, 3: front wheels, 4: rear wheels, 5: carrier, 6: lifting cylinder, 7: GNSS antenna, 8: GNSS receiver, 9: front external sensor, 10: left side External sensor 11: Right external sensor 12: Rear external sensor 13: IMU 14: Velocity sensor 15: Communication device 20: Control device 21: Position/orientation estimator 22: Route setting unit 23: Route follow-up control unit 24: road unevenness obstacle detection unit 25: collision determination unit 26: storage unit 27: map DB 30: control station 31: communication device 32: route planning unit 33: map DB , 100: autonomous driving system, 604: front maximum reach, 605: rear maximum reach, 606: steady turning impenetrable area, 607, 609, 610: end point, 608: line segment

Claims

A mining machine that autonomously travels in a mine, comprising a pair of steered front wheels arranged on both left and right sides of a vehicle body and a pair of rear wheels arranged on both left and right sides of the vehicle body,
The mining machine is equipped with a plurality of external sensors for detecting road surface conditions and obstacles in front, sides and rear of the mining machine,
A maximum reaching range of the mining machine at maximum braking, which is obtained based on the relationship between a preset speed range and a maximum steering angle, and a steady state in which the mining machine cannot enter when the mining machine turns at the maximum steering angle. A stoppable range of the mining machine is set by a turning impenetrable area and a line segment parallel to the direction of the vehicle body and connecting an end point of the maximum reachable area and the steady turning impenetrable area,
The mining machine, wherein the plurality of external sensors are arranged such that a detection range includes the stoppable range.
The mining machine according to claim 1, wherein the maximum reaching range is obtained based on a preset relationship between a speed range and a maximum steering angle, and the position and orientation of the center of gravity of the mining machine.
3. The mining machine according to claim 1, wherein the detection range of the external sensor arranged in front of the mining machine and the detection range of the external sensor arranged to the side of the mining machine partially overlap. .
further comprising a control device that performs at least travel control of the mining machine based on the detection result of the external sensor;
When the obstacle detected by the external sensor exists within the steady turning impenetrable area,
4. The control device according to any one of claims 1 to 3, wherein the control device excludes obstacles detected by the external sensor from target obstacles for stop processing of the mining machine, and controls travel of the mining machine. mining equipment.
When the external sensor disposed on the side of the mining machine has a non-detectable range, and the non-detectable range is within the steady turning non-aggression zone,
5. The mining machine according to claim 4, wherein the control device allows the mining machine to continue running.
The control device is
a position and orientation estimation unit that estimates the position and orientation of the mining machine;
a route setting unit that sets a route based on map information;
a route following control unit that controls the steering and speed of the mining machine so as to follow the set route;
The mining machine according to claim 4 or 5, comprising:
An autonomous traveling system comprising a plurality of mining machines according to any one of claims 4 to 6, and a control station configured to be able to communicate with each mining machine and managing the plurality of mining machines. hand,
In response to a route request from any of the mining machines, the control station determines the traveling route of the mining machine that requested the route and the positions of other mining machines that exist around it. send to
The autonomous traveling system, wherein the control device of the mining machine that has received the route request performs traveling control of the own machine based on the traveling route and the positions of the other mining machines transmitted from the control station.