Position estimation device, autonomous vehicle, and position estimation program

Abstract

To appropriately perform position estimation.SOLUTION: An unmanned carrier 1 comprises: a distance sensor 24 mounted on a drivable vehicle body 10 and capable of acquiring two-dimensional distance information around the vehicle body; a storage unit 26 in which a 3D map 261 is preliminarily stored; and a control unit 27. The control unit 27 estimates a position of the vehicle body 10 on the basis of the two-dimensional distance information acquired by the distance sensor 24 and the 3D map 261.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to a position estimation device, an autonomous vehicle, and a position estimation program. [Background technology]

[0002] 2. Description of the Related Art Conventionally, in an automatically driven vehicle or the like, a self-location is sequentially estimated based on information acquired from the surrounding situation. For example, in the technology described in Patent Document 1, surrounding point cloud information is acquired by three-dimensional LiDAR (LASER Imaging Detection and Ranging), and this is compared with map data to estimate the vehicle's own position. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2019-109332 Summary of the Invention [Problem to be solved by the invention]

[0004] However, while position estimation based on 3D surrounding information allows estimation of six degrees of freedom (3 translational and 3 rotational), it incurs high computational costs. Also, 3D measurement devices such as 3D-LiDAR that can obtain 3D surrounding information are more expensive than 2D measurement devices.

[0005] The present invention has been made in view of the above circumstances, and has an object to perform position estimation in a suitable manner. [Means for solving the problem]

[0006] The position estimation device according to the present invention comprises: a measuring means mounted on a vehicle body capable of moving and capable of acquiring two-dimensional distance information about its surroundings; a storage means for storing three-dimensional map information in advance; an estimation means for estimating a position of the vehicle body based on the two-dimensional distance information acquired by the measurement means and the three-dimensional map information; Equipped with 、 the storage means stores in advance information about the slope of the terrain; The estimation means estimates the position of the vehicle body based on the two-dimensional distance information and the three-dimensional map information, while supplementarily using the tilt information. The composition was as follows. Furthermore, the position estimation device according to the present invention comprises: a measuring means mounted on a vehicle body capable of moving and capable of acquiring two-dimensional distance information about its surroundings; a storage means for storing three-dimensional map information in advance; an estimation means for estimating a position of the vehicle body based on the two-dimensional distance information acquired by the measurement means and the three-dimensional map information; Equipped with the storage means stores in advance information on the height of the terrain; The estimation means is configured to estimate the position of the vehicle body based on the two-dimensional distance information and the three-dimensional map information, while supplementarily using the height information.

[0007] The autonomous vehicle according to the present invention comprises: The position estimation device; The vehicle body; The configuration is provided with the following.

[0008] The position estimation program according to the present invention comprises: A computer of a position estimation device is mounted on a vehicle body capable of travelling, and includes a measuring means capable of acquiring two-dimensional distance information of the surrounding area, and a storage means in which three-dimensional map information is stored in advance, an estimation means for estimating a position of the vehicle body based on the two-dimensional distance information acquired by the measurement means and the three-dimensional map information; Function as 、 the storage means stores in advance information about the slope of the terrain; The estimation means estimates the position of the vehicle body based on the two-dimensional distance information and the three-dimensional map information, while supplementarily using the tilt information. It was decided. Furthermore, the position estimation program according to the present invention includes: A computer of a position estimation device is mounted on a vehicle body capable of travelling, and includes a measuring means capable of acquiring two-dimensional distance information of the surrounding area, and a storage means in which three-dimensional map information is stored in advance, an estimation means for estimating a position of the vehicle body based on the two-dimensional distance information acquired by the measurement means and the three-dimensional map information; It functions as the storage means stores in advance information on the height of the terrain; The estimation means estimates the position of the vehicle body based on the two-dimensional distance information and the three-dimensional map information, while supplementarily using the height information. [Effects of the Invention]

[0009] According to the present invention, position estimation can be performed suitably. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 2 is a diagram illustrating a working state of an automated guided vehicle according to the embodiment. [Figure 2] 1 is a block diagram showing a schematic control configuration of an automated guided vehicle according to an embodiment; [Figure 3] FIG. 4 is a diagram for explaining a normal map according to the embodiment. [Figure 4] 10 is a flowchart illustrating a flow of a position estimation process according to the embodiment. [Figure 5] FIG. 10 is a diagram illustrating an example of a route search using a normal map. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

[0012] [Configuration of automated guided vehicles] FIG. 1 is a diagram showing a working state of an automatic guided vehicle 1 according to this embodiment. As shown in this figure, the automated guided vehicle 1 according to this embodiment is an automated guided forklift (AGF) that transports loads L in an unmanned manner, for example, in a warehouse or a factory, and performs predetermined loading and unloading operations based on operation commands from a management server 40 (see FIG. 2). The automated guided vehicle 1 is an example of an autonomous vehicle according to the present invention, and by being equipped with a position estimation device according to the present invention, it can perform loading and unloading operations while suitably estimating its own position in a work area (travel area) that includes an inclined surface S.

[0013] Specifically, the vehicle body 10 of the automated guided vehicle 1 includes a vehicle body 11, forks 12, a lift (lift) 13, a mast 14, and wheels 15. The mast 14 is provided in front of the vehicle body 11 and is driven by a drive source (not shown) to tilt the vehicle body 11 forward and backward. The lift 13 is driven by a drive source (not shown) to rise and lower along the mast 14. A pair of left and right forks 12 for holding loads L, pallets, etc. are attached to the lift 13. The pair of forks 12 can tilt and rise and lower relative to the vehicle body 11 by driving the mast 14 and the lift 13.

[0014] FIG. 2 is a block diagram showing a schematic control configuration of the automatic guided vehicle 1. As shown in FIG. As shown in this figure, in addition to the above configuration, the automated guided vehicle 1 is equipped with a drive unit 21, a communication unit 23, a distance sensor 24, an inertial measurement unit (IMU) 25, a memory unit 26, and a control unit 27. The position estimation device according to the present invention includes the distance sensor 24, the memory unit 26, and the control unit 27.

[0015] The drive unit 21 includes a travel motor, a steering motor, and a cargo handling motor (all not shown), which are various drive sources of the automated guided vehicle 1. The travel motor drives the drive wheels of the wheels 15. The steering motor rotates (steers) the steering wheels of the wheels 15. The cargo handling motor is a drive source that performs the respective operations of raising and lowering the lifting body 13 and tilting the mast 14. The communication unit 23 communicates with the management server 40, etc. The communication by the communication unit 23 may be performed directly with the communication unit of the management server 40, etc., or may be performed via a communication network. The management server 40 is a computer that manages the transport system including the automatic guided vehicle 1, and transmits operation commands to the automatic guided vehicle 1 based on user operations or a predetermined program.

[0016] The distance sensor 24 is capable of acquiring distance information (depth information) of a predetermined two-dimensional area around the vehicle body 10, and outputs the acquired information to the control unit 27. The distance sensor 24 is an example of a measuring means according to the present invention, and in this embodiment is a two-dimensional LiDAR (LASER Imaging Detection and Ranging). The distance sensor 24 of this embodiment is installed on the top surface of the vehicle body 11 (see FIG. 1), and measures a predetermined radial area within a plane that is approximately perpendicular to the up-down direction of the vehicle body 11. However, the measurement area of ​​the distance sensor 24 may be any flat area.

[0017] The inertial measurement unit 25 measures the three-dimensional acceleration and angular velocity of the automatic guided vehicle 1 and outputs the results to the control unit 27 .

[0018] The control unit 27 includes, for example, a CPU (Central Processing Unit), and controls the operation of each part of the automated guided vehicle 1. Specifically, the control unit 27 operates the drive unit 21 based on an operation command received from the management server 40 via the communication unit 23, deploys a program pre-stored in the storage unit 26, and executes various processes in cooperation with the deployed program.

[0019] The storage unit 26 is a memory configured by a RAM (Random Access Memory), a ROM (Read Only Memory), etc., and stores various programs and data, and also functions as a work area for the control unit 27. The storage unit 26 of this embodiment stores a position estimation program 260, a 3D map 261, a normal map 262, and an elevation map 263 in advance. The position estimation program 260 is a program for executing a position estimation process (see FIG. 4) to be described later.

[0020] In this embodiment, the 3D map 261 is three-dimensional point cloud data of the work area. The 3D map 261 is not particularly limited, but is acquired in advance, for example, by having an automated guided vehicle 1 equipped with a three-dimensional LiDAR (distance sensor) travel through the work area and measure the terrain using the three-dimensional LiDAR. This 3D mapping is performed, for example, whenever the layout of the work area is changed, and the 3D map 261 is updated to the latest version. Note that the 3D map 261 may be three-dimensional map information (topographical information) of at least an area including the work area.

[0021] The normal map 262 is slope information of the work area that includes information on the normal direction of the terrain surface (the road surface on which the automated guided vehicle 1 travels in this embodiment), and is acquired in advance from the 3D map 261. Specifically, for example, when there is terrain as shown in FIG. 3(a), the normal vectors (x, y, z coordinate values) of each grid are first acquired. The x, y, z values ​​of the acquired normal vectors are converted into RGB values ​​to generate the two-dimensional color map shown in FIG. 3(b), and this is then reduced in dimension to a two-dimensional grid map as shown in FIG. 3(c), thereby generating the normal map 262. The elevation map 263 is height information of the work area including altitude information of the terrain, and is acquired in advance from the 3D map 261. The normal map 262 and the elevation map 263 do not have to be acquired from the 3D map 261 as long as they each contain the necessary information (tilt information and height information).

[0022] [Location estimation processing] Next, an operation of the automatic guided vehicle 1 during loading and unloading work when it executes the position estimation process will be described. Fig. 4 is a flowchart showing the flow of the position estimation process. The position estimation process is a process in which the automated guided vehicle 1 estimates its own position during cargo handling work, and is executed by the control unit 27 of the automated guided vehicle 1 reading and deploying the position estimation program 260 from the memory unit 26. During cargo handling work, the automated guided vehicle 1 acquires its own position through the position estimation process, and performs various operations (picking up, loading, unloading, transporting, etc.) on the cargo L within the work area based on a predetermined program or operation commands from the management server 40.

[0023] As shown in FIG. 4, when the position estimation process is executed, first, the control unit 27 acquires distance information of a two-dimensional area around the vehicle body 10 using the distance sensor 24 (two-dimensional LiDAR) (step S1).

[0024] Next, the control unit 27 compares the acquired two-dimensional distance information with the 3D map 261 (step S2). At this time, the control unit 27 matches the distance information with the 3D map 261 while auxiliary using the normal map 262 and the elevation map 263. That is, in this matching, the position and posture including the height of the vehicle body 10 are estimated by using the normal map 262 and the elevation map 263, and the acquired two-dimensional distance information is compared with the 3D map 261. Then, a position on the 3D map 261 that matches favorably is calculated as the vehicle position.

[0025] This makes it possible to calculate the vehicle position by appropriately considering the attitude (inclination) and height position of the vehicle body 10 without using a three-dimensional measuring means. That is, position estimation using three-dimensional measurement means allows estimation of six degrees of freedom (three translational and three rotational), but the calculation costs are accordingly high and the measuring equipment is relatively expensive. On the other hand, position estimation using two-dimensional measurement means requires less expensive measuring equipment and reduces calculation costs, but the calculation degrees of freedom are limited to three (two translational and one rotational), making it difficult to apply to uneven terrain. In this regard, in this embodiment, the posture and height position of the vehicle body 10 can be suitably taken into consideration without requiring three-dimensional measurement means.

[0026] In step S2, the normal map 262 and the elevation map 263 are used supplementarily, but the two-dimensional distance information and the 3D map 261 may be matched without using these. However, it goes without saying that using at least one of the normal map 262 and the elevation map 263 is preferable, particularly in terms of reducing the number of calculations. If either one is used, it is more preferable to use the normal map 262. Further, instead of the normal map 262 and the elevation map 263, other sensors may be used to acquire information on the height and tilt (attitude) of the vehicle body 10. For example, the attitude information may be acquired from the inertial measurement unit 25.

[0027] Next, the control unit 27 determines whether or not to terminate the position estimation process (step S3), and if it determines not to terminate it (step S3; No), it transitions to the above-mentioned step S1 and continues to repeatedly estimate (calculate) its own position during loading and unloading operations. Then, when it is determined that the position estimation process should be ended due to, for example, the end of the loading and unloading work (step S3; Yes), the control unit 27 ends the position estimation process.

[0028] [Technical effect of this embodiment] As described above, according to this embodiment, the position of the vehicle body 10 is estimated based on the two-dimensional distance information acquired by the distance sensor 24 and the 3D map 261. This reduces the calculation cost compared to position estimation based on three-dimensional distance information. Furthermore, the distance sensor 24 that acquires two-dimensional distance information can be inexpensive compared to three-dimensional measuring devices such as 3D-LiDAR. Furthermore, the control unit 27 can also be inexpensive and have lower computing power. Therefore, position estimation can be performed more effectively than position estimation based on three-dimensional distance information from 3D-LiDAR or the like.

[0029] Furthermore, according to this embodiment, by using the normal map 262 and the elevation map 263, it is possible to estimate the vehicle position by appropriately considering the attitude (inclination) and height position of the vehicle body 10. Therefore, it is possible to appropriately estimate the vehicle position even in a work area that includes elevation differences.

[0030] [others] Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments (including modifications). For example, in the position estimation process of the above embodiment, the normal map 262 may be used to perform a route search that takes into account the slope and height of the terrain. In this case, if there is no anisotropy in the allowable acceleration in the longitudinal and transverse directions of the vehicle body 10, the cost of traveling on an inclined surface can be incorporated into a path search algorithm such as the A* algorithm, and the angle between the normal and the Z axis can be integrated as the cost. As a result, for example, if the cost of an inclined surface is high, a path that avoids the inclined surface as much as possible can be obtained. Alternatively, for example, as shown in FIG. 5(a), a path that travels on an inclined surface within the allowable inclination range of the vehicle body 10 can be obtained. Furthermore, if there is anisotropy in the allowable acceleration in the longitudinal and transverse directions of the vehicle body 10, the normal map 262 can be incorporated into the hybridA* algorithm to integrate the costs due to posture from the relationship between the gravity vector and an ellipse with the normal as its axis. As a result, a path traveling on an inclined surface in the longitudinal direction of the vehicle body 10 can be obtained as a posture with low cost, for example, as shown in Figure 5(b).

[0031] In the above embodiment, the position estimation device is mounted on an automated guided vehicle. However, the object on which the position estimation device according to the present invention is mounted is not limited to an automated guided vehicle as long as it is a moving object that performs self-position estimation. For example, the device may be mounted on a vehicle such as a forklift or construction machine, a mobile robot, or a drone (unmanned aerial vehicle). It may also be a manned aircraft with a driver on board. The place where it is used is not limited to a warehouse, factory, or construction site, and it can be widely applied to places (terrain) with undulations (height differences) such as slopes. Furthermore, the position estimation device (position estimation program) according to the present invention does not have to be installed in a mobile object, but may be implemented in a control means (for example, management server 40) capable of communicating with the mobile object.

[0032] In addition, in the above embodiment, an unmanned guided vehicle was used as an example of an autonomous vehicle according to the present invention, but the autonomous vehicle according to the present invention may be any vehicle that is capable of automatic driving (autonomous driving) and does not need to be equipped with a transportation function. In addition, the details shown in the above embodiment can be modified as appropriate without departing from the spirit of the invention. [Explanation of symbols]

[0033] 1. Autonomous vehicles 10. Body 24 Distance sensor (measurement means) 25 Inertial Measurement Unit 26 Storage unit (storage means) 27 Control unit (estimation means) 260 Location Estimation Program 261 3D Map (three-dimensional map information) 262 Normal map (tilt information) 263 Elevation map (height information) S inclined plane

Claims

1. a measuring means mounted on a vehicle body capable of moving and capable of acquiring two-dimensional distance information about its surroundings; a storage means for storing three-dimensional map information in advance; an estimation means for estimating a position of the vehicle body based on the two-dimensional distance information acquired by the measurement means and the three-dimensional map information; Equipped with the storage means stores in advance information about the slope of the terrain; the estimation means estimates the position of the vehicle body based on the two-dimensional distance information and the three-dimensional map information while supplementarily using the tilt information. Location estimation device.

2. The storage means stores terrain height information in advance, the estimation means estimates the position of the vehicle body based on the two-dimensional distance information and the three-dimensional map information while supplementarily using the height information. The position estimation device according to claim 1 .

3. A measuring means mounted on a vehicle body capable of moving and capable of acquiring two-dimensional distance information about its surroundings; a storage means for storing three-dimensional map information in advance; an estimation means for estimating a position of the vehicle body based on the two-dimensional distance information acquired by the measurement means and the three-dimensional map information; Equipped with the storage means stores in advance information on the height of the terrain; the estimation means estimates the position of the vehicle body based on the two-dimensional distance information and the three-dimensional map information while supplementarily using the height information. Location estimation device.

4. The measurement means is a two-dimensional LiDAR; The position estimation device according to any one of claims 1 to 3.

5. The three-dimensional map information includes point cloud data. The position estimation device according to any one of claims 1 to 4.

6. A position estimation device according to any one of claims 1 to 5; The vehicle body; An autonomous vehicle comprising:

7. A computer of a position estimation device is mounted on a vehicle body capable of travelling, and includes a measuring means capable of acquiring two-dimensional distance information of the surrounding area, and a storage means in which three-dimensional map information is stored in advance, an estimation means for estimating a position of the vehicle body based on the two-dimensional distance information acquired by the measurement means and the three-dimensional map information; It functions as the storage means stores in advance information about the slope of the terrain; the estimation means estimates the position of the vehicle body based on the two-dimensional distance information and the three-dimensional map information while supplementarily using the tilt information. Location estimation program.

8. A computer of a position estimation device that is mounted on a vehicle body capable of travelling and that includes a measuring means capable of acquiring two-dimensional distance information of the surrounding area and a storage means that stores three-dimensional map information in advance, an estimation means for estimating a position of the vehicle body based on the two-dimensional distance information acquired by the measurement means and the three-dimensional map information; It functions as the storage means stores in advance information on the height of the terrain; the estimation means estimates the position of the vehicle body based on the two-dimensional distance information and the three-dimensional map information while supplementarily using the height information. Location estimation program.

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