Vehicle Inspection Equipment

Abstract

To prevent a LiDAR device 11 of a test vehicle 1 from detecting a test apparatus 5 on an examination room floor surface 4.SOLUTION: A mirror device 12 is provided for a LiDAR device 11 to cover the upper part of a test apparatus 5. The mirror device 12 includes: a first planer mirror 13 along a horizontal surface with an inner end edge 13a extending to a test vehicle 1 side; and a second inclined planer mirror 14 with an outer end edge 14a extending to a side wall 2 side. Each length and each angle are set so that a laser beam from the LiDAR device 11 will be guided to a ceiling. A light absorbent 17 is attached to the inner surface and the side wall 2 of the ceiling wall 16.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a vehicle inspection device that tests the autonomous driving performance of a test vehicle equipped with an optical laser device for detecting obstacles in an inspection room. [Background technology]

[0002] Vehicle inspection devices that use a dynamometer to perform bench tests indoors that simulate the running conditions of a vehicle have been in practical use for some time now. For example, Patent Document 2 discloses a vehicle inspection device in which the driving wheels are rotated by a chassis dynamometer, while the axles of the driven wheels are rotated by a wheel drive device disposed on the side of the vehicle.

[0003] In recent years, there has been a demand for bench testing of driving performance, such as automatic braking performance, when an obstacle is detected for vehicles equipped with an optical laser device (e.g., LiDAR device) for obstacle detection. In such vehicles, if the optical laser device mistakenly detects surrounding test equipment as an obstacle, a response such as automatic braking will occur, making inspection virtually impossible.

[0004] Patent Document 1 discloses a vehicle inspection device in which plate-shaped absorbing material is placed in close proximity to each LiDAR device, facing the LiDAR devices placed in multiple locations on the vehicle, so that the vehicle is recognized as if it is traveling through a grassland free of obstacles. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] International Publication No. 2020 / 059497 [Patent Document 2] JP 2016-061668 A Summary of the Invention [Problem to be solved by the invention]

[0006] For example, LiDAR devices generally use laser light with a short wavelength as an electromagnetic wave for measuring the distance to an obstacle. With regard to the laser light used in such LiDAR devices, under current technology, there is no absorbent material that can absorb 100%, and light scattering occurs to a certain extent. In the device of Patent Document 1, an absorbent material is arranged close to the LiDAR device to block the light path of the LiDAR device, so if scattering occurs in the absorbent material arranged close to the LiDAR device, the LiDAR device will detect it. In other words, it is considered that the device of Patent Document 1 cannot actually prevent the LiDAR device from detecting the presence of an obstacle.

[0007] Furthermore, in order to evaluate the automatic braking performance when, for example, a pedestrian suddenly appears in front of the vehicle, an obstacle simulating a pedestrian is placed in front of the vehicle on a stand during a driving test. However, in Patent Document 1, the LiDAR device is covered with an absorbent material, making it impossible to verify the operation of the LiDAR device in an emergency. [Means for solving the problem]

[0008] The present invention is a vehicle inspection device for testing the autonomous driving performance of a test vehicle equipped with an optical laser device for obstacle detection in an inspection room surrounded by side walls on at least three sides, comprising: one or more test devices disposed on the side of the test vehicle; a mirror covering an upper surface of the test equipment and directing the light emitted from the optical laser device upward; The present invention is configured to include the following features.

[0009] An example of an optical laser device is a LiDAR (Light Detection and Ranging) device. However, the present invention is not limited to this, and any type of device may be used as long as it detects an obstacle by projecting and receiving laser light.

[0010] In the above configuration, the light projected from the optical laser device toward the surrounding test equipment is reflected by the mirror and directed upwards, so the test equipment is not detected as an obstacle.

[0011] In one preferred aspect of the present invention, the mirror has an inner edge extending toward the test vehicle at a height position between the optical laser device of the test vehicle and the test equipment, and an outer edge extending toward the side wall at a position at least higher than the optical laser device, and is curved or bent so as to guide the light emitted from the optical laser device toward the ceiling of the inspection room.

[0012] In the above configuration, the light reflected by the mirror is directed toward the ceiling. This makes the light path longer and attenuation occurs over distance, so even if there is a small amount of scattering on the ceiling, it will not be detected as an obstacle.

[0013] In one preferred embodiment of the present invention, the interior surface of the ceiling of the examination room is covered with a light absorbing material, so that light that strikes the ceiling surface is absorbed and prevented from returning to the optical laser device.

[0014] In one example, an intermediate ceiling wall is suspended between the test vehicle and the ceiling to cover the optical laser device, and the upper surface of the intermediate ceiling wall is covered with a light absorbing material, thereby suppressing the light reflected by the ceiling surface from entering the optical laser device.

[0015] In another preferred embodiment, the ceiling of the examination room is open, in which case the optical path length is infinite and there is no scattering at the ceiling.

[0016] The mirror can be curved, such as a parabolic or spherical mirror focused on the optical laser device, but in a preferred embodiment, the mirror is a combination of plane mirrors, which makes it easier to implement the invention.

[0017] In a specific embodiment, when viewed in a cross section along the vertical direction on one side of the test vehicle, the mirror is configured by combining two plane mirrors, a first plane mirror that includes the inner edge and is arranged horizontally, and a second plane mirror that includes the outer edge and is arranged at an angle. By using two plane mirrors in this way, the number of boundaries or gaps between the plane mirrors that are easily detected by the optical laser device is minimized.

[0018] More specifically, when the height (Hs+a) of the outer edge is defined as the height (L) of the optical laser device plus a margin (a), the length (W) of the first plane mirror, the installation height (Hd) of the first plane mirror, the length (M) of the second plane mirror, and the inclination angle (θ0) of the second plane mirror with respect to the vertical plane are expressed as follows: W=L / 2*(1+cos(2*θ0)) Hd=L*(1-sin(2*θ0) / 2) M=L*sinθ0 It is desirable that the following relationship is satisfied.

[0019] By satisfying this relationship, the optical path of the light projected from the optical laser device and reflected by the mirror is directed toward the ceiling or at least a position on the side wall that is higher than the optical laser device. Therefore, there is no optical path that is reflected on the side wall and returns to the optical laser device.

[0020] The test equipment is, for example, a dynamometer that is connected to the axle of the test vehicle to measure the driving force. Effect of the Invention

[0021] According to this invention, test equipment such as a dynamometer arranged on the side of a test vehicle equipped with an optical laser device is no longer detected as an obstacle, making it possible to test automatic driving performance such as automatic braking using the optical laser device. [Brief description of the drawings]

[0022] [Figure 1]FIG. 2 is a plan view showing a schematic configuration of an examination chamber according to the first embodiment. [Diagram 2] Cross-sectional view taken along line AA in Figure 1. [Diagram 3] FIG. 1 is a perspective view showing a mirror configuration in which plane mirrors are combined. [Figure 4] FIG. 2 is an explanatory diagram for explaining the relationship between the lengths and angles of two plane mirrors. [Diagram 5] FIG. 11 is a cross-sectional view of a second embodiment with an intermediate ceiling wall. [Figure 6] FIG. 11 is a cross-sectional view of the third embodiment with the roof open. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0023] An embodiment of the present invention will now be described in detail with reference to the drawings.

[0024] Fig. 1 is a plan view showing the internal configuration of the inspection room of the first embodiment, and Fig. 2 is a cross-sectional view taken along line AA. As shown in these figures, the inspection room is a rectangular room in which a test vehicle 1, which is the subject of bench testing, is placed in the center in a plan view, and the test vehicle 1 is surrounded on three sides, the left and right sides, and the rear, by side walls 2. The face of the inspection room in front of the test vehicle 1 (indicated by reference symbol 3) is either open for carrying in and out the test vehicle 1 and for testing such as obstacle detection in front of the test vehicle 1, or is equipped with a large door (not shown) that can be opened and closed.

[0025] A plurality of test devices 5 are installed on the floor 4 of the inspection room. The test devices 5 are, for example, dynamometers connected to the front and rear axles of the test vehicle 1, respectively, to measure driving force and braking force during braking. In the illustrated example, two test devices 5 (dynamometers) are arranged on each of the left and right sides of the test vehicle 1, corresponding to the front and rear axles, respectively. Depending on the content of the test, there are cases where the test devices 5 (dynamometers) are connected to only one of the front and rear wheels. Also, in the present invention, the test devices 5 are not necessarily limited to dynamometers.

[0026] The test vehicle 1 is provided with a LiDAR device 11 in the center of the roof in the front-rear direction. More specifically, a pair of LiDAR devices 11 are provided on the left and right sides near the side edges of the roof. The LiDAR device 11 projects laser light in a manner that scans a wide range, and detects the presence or absence of an obstacle and the distance to the obstacle by receiving the light that hits the obstacle and is reflected. The LiDAR device is sometimes called a "lidar" or "LADAR". In the embodiment, the LiDAR device 11 is located at a higher position than the test equipment 5, but since the laser light is scanned not only in the front-rear direction of the vehicle but also in the up-down direction, if left as is, the LiDAR device 11 may recognize the test equipment 5 as an obstacle, and the test vehicle 1 may be controlled to a state in which it cannot run.

[0027] In order to avoid such detection of the test equipment 5 by the LiDAR device 11, in one embodiment, a mirror device 12 is provided in the inspection room. As shown in FIG. 2, the mirror device 12 is configured by combining a first plane mirror 13 arranged along a horizontal plane so as to surround the periphery of the test vehicle 1, and a second plane mirror 14 arranged at an angle on the outer periphery side of the first plane mirror 13. In other words, the two plane mirrors 13 and 14 are combined so as to be continuous with each other in a bent shape. As will be described later, the angles and lengths of the two plane mirrors 13 and 14 are set so as to guide the laser light emitted from the LiDAR device 11 toward the ceiling of the inspection room.

[0028] 2, the first plane mirror 13 has an inner edge 13a extending toward the test vehicle 1, and is located at a height between the LiDAR device 11 and the test equipment 5 so as to cover the test equipment 5 from the line of sight of the LiDAR device 11. The inner edge 13a is sufficiently close to the side of the test vehicle 1 so that the test equipment 5 is not visible to the LiDAR device 11.

[0029] The second plane mirror 14, which is disposed at an angle with respect to the horizontal plane, has an outer edge 14a extending toward the side wall 2. The outer edge 14a may have an appropriate distance between it and the inner wall surface of the side wall 2, but its height position is at least higher than the LiDAR device 11. In other words, the inner wall surface of the side wall 2 is covered from the line of sight of the LiDAR device 11 up to a position higher than the LiDAR device 11.

[0030] A ceiling wall 16 along a horizontal plane is provided on the ceiling of the examination room, and a light absorbing material 17 for absorbing the laser light from the LiDAR device 11 is attached to the inner surface (i.e., the lower surface) of this ceiling wall 16. In other words, the entire surface of the ceiling wall 16 is covered with the light absorbing material 17. The light absorbing material 17 is selected with characteristics taking into consideration the wavelength of the laser light, and may be, for example, a light absorbing material with a smooth surface or a light absorbing material with an uneven surface.

[0031] In addition, the upper inner wall surface of the side wall 2 connected to the ceiling wall 16, more specifically, the upper area that is exposed and not hidden by the outer edge 14a of the second plane mirror 14 when viewed from the LiDAR device 11, is also covered with light absorbing material 17.

[0032] The thin lines in FIG. 2 indicate several optical paths of the laser light reflected by the mirror device 12.

[0033] As shown in Fig. 1, the mirror device 12 is provided so as to surround three sides (left and right sides and rear) of the test vehicle 1 except the front. The front is open and does not have a mirror because it is necessary for the LiDAR device 11 to detect obstacles simulating pedestrians, etc., for testing the automatic braking performance. In other words, the mirror device 12 is configured to be substantially U-shaped in a plan view. The rear mirror can be omitted if there is no test equipment 5 to be covered.

[0034] Here, the second plane mirrors 14A (see FIG. 3) located at both ends of the mirror device 12 in the vehicle front-rear direction, i.e., at the four corners of the rectangular inspection room, are inclined toward the center of the inspection room in a plan view of the inspection room. In other words, the mirror surfaces at the four corners face inward so that the entire mirror device 12 approaches the shape of a parabolic mirror.

[0035] FIG. 3 shows a more specific configuration of the mirror device 12. As shown in the figure, the mirror device 12 is divided into a plurality of sections along the longitudinal direction of the U-shape, and each section is provided with a table-like stand 21 made of a metal channel material. The first plane mirror 13 divided into each section is attached along the upper surface of the stand 21. The second plane mirror 14 is attached to rise obliquely from the upper surface of the stand 21, and the second plane mirror 14 is supported from the back side by a beam 21a extending obliquely from the stand 21. The first plane mirror 13 and the second plane mirror 14 are configured, for example, by mirror-finishing one surface of a flat metal plate. The boundary between the first plane mirror 13 and the second plane mirror 14 is arranged in a state where both are in contact with each other so that there is as little gap as possible. The second plane mirror 14A located at the corner portion described above is formed into a trapezoidal shape taking into account the angle facing inward so that it is continuous with the adjacent second plane mirror 14 without any gap. Note that FIG. 3 shows only a part of the mirror device 12, which has a substantially U-shape as a whole.

[0036] 3, the test equipment 5 is housed in the inner space of the stand 21 of the mirror device 12. The stand 21 is divided into multiple pieces, and the peripheral legs 21b each independently protrude downward from the upper surface of the stand 21, so that the mirror device 12 can be installed by placing the stand 21 from above over the test equipment 5 that has already been installed on the floor of the examination room.

[0037] According to the configuration of the first embodiment, the laser light emitted from the LiDAR device 11 is reflected by the mirror device 12 and guided toward the ceiling, and is finally absorbed by the light absorbing material 17 on the ceiling wall 16 or the upper part of the side wall 2. In this way, a long distance is ensured from the LiDAR device 11 to the light absorbing material 17, and the return distance from the point of the light absorbing material 17 where the laser light hits to the LiDAR device 11 is also long, so that attenuation due to distance is obtained, and even if some scattering occurs in the light absorbing material 17, the LiDAR device 11 will not detect it. Therefore, the test equipment 5 will not be recognized as an obstacle by the LiDAR device 11.

[0038] Next, with reference to FIG. 4, the lengths of the first plane mirror 13 and the second plane mirror 14 and the angle of the second plane mirror 14 required to obtain the above effect will be described.

[0039] 4 is a schematic diagram showing a cross section along the up-down direction on one side of the test vehicle 1. In the figure, L indicates the height position of the outer edge 14a of the second plane mirror 14. This height position L is set to a height (Hs+a) obtained by adding an appropriate margin a to the height Hs of the LiDAR device 11.

[0040] If the length of first plane mirror 13 is W, the installation height position of first plane mirror 13 is Hd, the length of second plane mirror 14 is M, and the inclination angle of second plane mirror 14 with respect to the vertical plane is θ0, it is desirable that these satisfy the relationships of the following equations (1), (2), and (3).

[0041] W = L / 2 * (1 + cos (2 * θ0)) … (1) Hd = L * (1 - sin (2 * θ0) / 2) ... (2) M = L * sinθ0 … (3) The boundary (bending point) between the first plane mirror 13 and the second plane mirror 14 that satisfies these relationships is always located on the arc indicated by the symbol S in FIG. 4. FIG. 4 illustrates two examples of combinations of the first plane mirror 13 and the second plane mirror 14 that satisfy the above relationships, and in either combination, the optical path of the laser light emitted in any direction from the LiDAR device 11 is directed upward above the height L of the ceiling surface or the side wall 2. Due to the relationship of the incidence angle with respect to these ceiling surfaces or the side wall 2, an optical path that returns to the LiDAR device 11 never occurs. For example, even if the laser light that is incident on the side wall 2 is reflected by the side wall 2, it will head toward the ceiling and will not return to the LiDAR device 11.

[0042] Furthermore, if the clearance a at the height L were 0, that is, if the height L of the outer edge 14a were equal to the height Hs of the LiDAR device 11, the laser light incident perpendicularly on the side wall 2 could return to the LiDAR device 11, which is not preferable.

[0043] By combining two plane mirrors 13, 14 in this manner to obtain a desired optical path, the configuration of mirror device 12 can be simplified and the number of boundaries between the two plane mirrors that are prone to scattering light can be reduced.

[0044] Next, FIG. 5 shows a second embodiment in which an intermediate ceiling wall 31 is provided above the test vehicle 1 in the inspection room. The intermediate ceiling wall 31 is suspended from the ceiling wall 16 by a support 32 so as to be located between the test vehicle 1 and the ceiling wall 16, and covers the upper part of the LiDAR device 11. It is desirable that the intermediate ceiling wall 31 has a size sufficient to block at least the optical path from the entire ceiling wall 16 to the LiDAR device 11. The upper surface of this intermediate ceiling wall 31 is covered with a light absorbing material similar to that described above. In order to suppress stray light, a light absorbing material may also be provided on the side surface and lower surface of the intermediate ceiling wall 31.

[0045] In this configuration, even if the laser light is reflected or scattered by the ceiling wall 16, the light will not reach the LiDAR device 11. In other words, the light that is reflected or scattered by the upper part of the side wall 2 or the ceiling wall 16 and attempts to travel toward the LiDAR device 11 is blocked by the intermediate ceiling wall 31.

[0046] In addition, since the upper limit angle of the scanning range of the LiDAR device 11 is generally relatively small, in this second embodiment, the laser light projected by the LiDAR device 11 does not directly strike the intermediate ceiling wall 31.

[0047] Next, Fig. 6 shows a third embodiment in which the ceiling of the examination room is open. In this third embodiment, the laser light reflected by the mirror device 12 and guided toward the ceiling heads directly to the outside. Therefore, the light does not return to the LiDAR device 11. Also, in this third embodiment, no light absorbing material 17 is provided on the upper part of the side wall 2. If the relationship of the above-mentioned formulas (1) to (3) is satisfied, even if the laser light is reflected by the side wall 2, it heads toward the open ceiling and does not affect the LiDAR device 11.

[0048] The ceiling of the testing room may be provided with a retractable ceiling wall that is left open during testing.

[0049] Although one embodiment of the present invention has been described in detail above with reference to the drawings, the present invention is not limited to the above embodiment and various modifications are possible. For example, the arrangement of the LiDAR device 11 in the test vehicle 1 is not limited to the both sides of the roof as in the above embodiment, and may be any arrangement. In addition, the mirror device 12 may be a combination of three or more plane mirrors, or may be a curved mirror.

[0050] In the above first to third embodiments, the laser light reflected by the mirror device 12 is guided toward the ceiling, but in the case of an examination room where the distance to the side wall 2 is sufficiently long, for example, the laser light reflected by the mirror device 12 may be configured to be directed toward the side wall 2. [Explanation of symbols]

[0051] 1...Test vehicle 2...Side wall 5. Test equipment 11…LiDAR device 12...Mirror device 13...First plane mirror 14...Second plane mirror 17...Light absorbing material 21…Frame 31...Middle ceiling wall

Claims

1. A vehicle inspection device for testing the autonomous driving performance of a test vehicle equipped with an optical laser device for obstacle detection in an inspection room surrounded by side walls on at least three sides, one or more test devices disposed on the side of the test vehicle; a mirror covering an upper surface of the test equipment and directing the light emitted from the optical laser device upward; A vehicle inspection device comprising:

2. The mirror has an inner edge extending toward the test vehicle at a height between the optical laser device of the test vehicle and the test equipment, and an outer edge extending toward the side wall at a height at least higher than the optical laser device, and is curved or bent so as to guide the light emitted from the optical laser device toward the ceiling of the inspection room.

2. A vehicle inspection device according to claim 1.

3. 3. The vehicle inspection apparatus according to claim 2, wherein an inner surface of a ceiling of said inspection room is covered with a light absorbing material.

4. 3. A vehicle inspection apparatus according to claim 2, wherein the ceiling of said inspection room is open.

5. 5. A vehicle inspection device according to claim 2, wherein the mirror is configured by combining a plurality of plane mirrors.

6. 6. A vehicle inspection device as described in claim 5, wherein, when viewed in a cross section along the vertical direction on one side of the test vehicle, the mirror is configured by combining two plane mirrors: a first plane mirror arranged horizontally and including the inner edge, and a second plane mirror arranged at an angle and including the outer edge.

7. When the height (Hs+a) of the outer edge is defined as the height (L) of the optical laser device plus a clearance (a), the length (W) of the first plane mirror, the installation height (Hd) of the first plane mirror, the length (M) of the second plane mirror, and the inclination angle (θ0) of the second plane mirror with respect to the vertical plane are expressed as follows: W=L / 2*(1+cos(2*θ0)) Hd=L*(1-sin(2*θ0) / 2) M = L * sin θ0 7. The vehicle inspection device according to claim 6, wherein the following relationship is satisfied:

8. 4. A vehicle inspection device according to claim 3, wherein an intermediate ceiling wall is suspended between the test vehicle and the ceiling to cover the optical laser device above, and an upper surface of the intermediate ceiling wall is covered with a light absorbing material.

9. 9. A vehicle inspection apparatus according to claim 1, wherein the test equipment is a dynamometer connected to an axle of a test vehicle to measure driving force.

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