Radar inspection device

Abstract

To provide a radar inspection device that can reduce the risk of mis-detecting the direction of an optical axis by the floor reflection wave.SOLUTION: A radar inspection device 1 includes a reflector 11, a stand 12, and a shield part 20. The shield part 20 includes a shield plate 21. The shield plate 21 is fixed below a reflector 11 by a fixing part 22 and an arm 23. The shield plate 21 is in a rectangular shape that is long in the direction of reflection of the reflector 11. For example, the length of the shield plate 21 is set to 250 mm to 420 mm. The shield plate 21 is fixed in a position below the reflector 11 such that the front edge protrudes forward by a predetermined distance from an opening surface of the reflector 11.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present disclosure relates to a radar inspection device used for adjusting the optical axis of a radar device. [Background technology]

[0002] Each radar device may have manufacturing errors. Also, errors may occur in the position and attitude at which the radar device is assembled to the vehicle. In the radar device, if the optical axis is not oriented in a pre-designed direction, the position of an object cannot be correctly identified. Therefore, in a vehicle manufacturing factory or the like, after the radar device is assembled to the vehicle, work is performed to adjust the optical axis of the radar device. As disclosed in Patent Documents 1 and 2, the optical axis can be adjusted by installing a reflector for axis adjustment in front of the vehicle and based on the reception intensity of the reflected wave from the reflector. The optical axis may also be called the detection axis or radar axis. The reflector for axis adjustment may also be called a target. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2020-134209 A [Patent Document 2] JP 2005-98897 A Summary of the Invention [Problem to be solved by the invention]

[0004] The reflector may also reflect the search wave reflected by the floor back to the radar device. For convenience, in this disclosure, the search wave reflected by the floor surface and incident on the reflector is referred to as the floor reflected wave. The greater the strength of the floor reflected wave, the more likely the radar device is to erroneously detect the direction of the reflector. As a result, the accuracy of adjusting the optical axis may decrease.

[0005] The present disclosure has been made based on the above-mentioned problems, and one of its objectives is to provide a radar inspection device that can reduce the risk of erroneous detection of the direction in which the optical axis is pointing due to floor reflected waves. [Means for solving the problem]

[0006] One of the radar inspection devices disclosed herein includes a reflector (11) that reflects radio waves, and a shielding portion (20) that is disposed below the reflector and that blocks radio waves traveling from the floor surface toward the reflector.

[0007] According to the above configuration, the floor reflected wave is partially or entirely blocked by the blocking portion. In other words, the amount of floor reflected wave reaching the reflector can be reduced compared to when there is no blocking portion. Therefore, the risk of erroneous detection of the direction of the optical axis due to the floor reflected wave can be reduced.

[0008] In addition, the symbols in parentheses in the claims indicate a correspondence with the specific means described in the embodiments described below as one aspect, and do not limit the technical scope of the present disclosure. [Brief description of the drawings]

[0009] [Figure 1] 1 is a diagram for explaining an overview of a method for inspecting the optical axis of a radar device; [Diagram 2] FIG. 1 is a side view illustrating a schematic configuration of a radar device. [Diagram 3] FIG. 2 is an external perspective view showing a configuration of a reflector. [Figure 4] FIG. 4 is a diagram showing the shape of a shielding plate. [Diagram 5] 11A and 11B are diagrams showing other examples of the shape of the shielding plate. [Figure 6] 11 is a diagram for explaining the position of a shielding plate relative to a reflector. FIG. [Figure 7] FIG. 2 is a diagram showing the path of a floor-reflected wave that may enter a reflector. [Figure 8] 13 is a diagram conceptually illustrating the effect of a shielding plate. FIG. [Figure 9]FIG. 1 is a diagram illustrating a first comparative example. [Figure 10] FIG. 11 is a diagram illustrating a second comparative example. [Figure 11] FIG. 13 is a diagram illustrating a third comparative example. [Figure 12] FIG. 13 is a diagram showing a wave reflected by a shielding plate. [Figure 13] 11 is a cross-sectional view showing a shielding plate having a radio wave absorber provided on its upper surface. [Figure 14] FIG. 13 is a diagram showing a shielding plate whose upper surface has been treated to scatter search waves. [Figure 15] 13A and 13B are diagrams illustrating other examples of the shielding portion. [Figure 16] FIG. 13 is a diagram showing a configuration in which the shielding plate is disposed at an angle. [Figure 17] FIG. 13 shows an expandable shielding plate. [Figure 18] FIG. 13 shows a shielding part having joints for accommodating shielding plates. [Figure 19] FIG. 13 is a diagram showing the state in which the shielding plate is accommodated. [Figure 20] FIG. 13 is a diagram showing a configuration in which a shielding portion is attached to a reflector. [Figure 21] FIG. 13 is a diagram showing an inspection system in which a reflector is disposed a predetermined amount higher than a radar device in a radar inspection device having a shielding portion. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, an embodiment of the present disclosure will be described with reference to the drawings. The present disclosure is not limited to the following embodiments. The configurations disclosed below may be modified in various ways without departing from the scope of the present disclosure. Various modified examples may be appropriately combined and implemented within the scope of no technical contradiction. The present disclosure also includes configurations that are not explicitly shown and are formed by combining multiple modified examples. In the following description, the same reference numerals are used for components having the same functions, and specific descriptions thereof may be omitted. When only a portion of the configuration is mentioned, the description given elsewhere may be applied to the other portions. Some configurations shown in the drawings may be enlarged / reduced for convenience of explanation.

[0011] The configuration of the radar inspection device 1 will be described in detail below with reference to the drawings.

[0012] FIG. 1 is a diagram showing a schematic overall view of a system for inspecting the optical axis of a radar device 9 using a radar inspection device 1. The radar inspection device 1 is a device used when inspecting the direction of the optical axis of a radar device 9 installed in a vehicle 8. The radar device 9 is a radar device that acquires target information by transmitting a search wave toward the outside of the vehicle 8. The search wave may be an electromagnetic wave in the millimeter wave band or a quasi-millimeter wave band. The radar device 9 generates target information by analyzing the reception result of the search wave (hereinafter, reflected wave) that is reflected by a three-dimensional object present within the emission range and returned. The target information may include the position and speed of a three-dimensional object present within the emission range. The position may be expressed by a distance and a direction.

[0013] The optical axis of the radar device 9 corresponds to the center line of the detection range of the radar device 9. In other words, the optical axis may be interpreted as the center of the angle range in which the radar device 9 can transmit a search wave, or the center of the angle range in which the radar device 9 can receive a reflected wave. The optical axis may be referred to as the detection axis or the central axis.

[0014] The radar device 9 may be mounted on the center of the front end of the vehicle 8, the left and right corners, the upper end of the windshield, etc., in order to obtain information about three-dimensional objects mainly existing in the area in front of the vehicle 8. The radar device 9 may be disposed on the back side of the front emblem, the center of the front bumper, or the center of the front grille. In the following, the radar device 9 is described as being mounted at the center of the front end of the vehicle 8, for example, at a position between the left and right headlights. In other embodiments, the radar device 9 may be disposed at the left and right corners of the front bumper. The present disclosure may also be applied to a radar device 9 that forms a detection range behind the vehicle 8. The radar device 9 may be provided in the center of the rear bumper, the left and right corners, the upper end of the rear window, etc. The following description may be appropriately changed depending on the mounting position of the radar device 9.

[0015] As an example, the radar device 9 is mounted in a position where the optical axis coincides with the front direction of the vehicle. That is, when the radar device 9 is mounted in a position as designed, the optical axis of the radar device 9 coincides with the front direction of the vehicle. However, due to an error during assembly and a manufacturing error of the radar device 9, the optical axis of the radar device 9 may deviate from the front direction. The front direction may be interpreted as the direction passing through the center of the vehicle 8 from the rear end to the front end.

[0016] The radar inspection device 1 is a device for measuring the degree of deviation of the optical axis, and is placed at a specified position in front of the vehicle 8. For example, the radar inspection device 1 is placed on the center line of the vehicle 8 (i.e. directly in front). As described below, the radar inspection device 1 includes a reflector 11, which is a module that reflects electromagnetic waves. The radar inspection device 1 is placed in front of the vehicle 8 with the reflector 11 facing the vehicle 8.

[0017] The degree of deviation of the optical axis of the radar device 9 is measured by the radar device 9 actually transmitting and receiving a search wave toward the reflector 11. The degree of deviation of the optical axis of the radar device 9 may be expressed as a difference between the detection direction of the reflector 11 and a predetermined reference direction. The detection direction may be data expressing the direction in which the reflector 11 exists as a vertical angle and a horizontal angle. The vertical angle is the angle in the vertical direction with respect to the optical axis. The horizontal angle is the angle in the horizontal direction with respect to the optical axis. The detection direction may be expressed with the azimuth and the direction in which the optical axis extends as the origin. For example, the horizontal angle may be expressed as an angle to the right of the vehicle as a positive value, and an angle to the left as a negative value. The vertical angle may be expressed as an angle in the upward direction as a positive value, and an angle in the downward direction as a negative value.

[0018] The reference direction is the detection direction of the reflector 11 when there is no misalignment of the optical axis. The reference direction may be interpreted as the correct direction. When the reflector 11 is placed directly in front of the radar device 9, the reference direction may be the origin direction. The origin direction is the direction in which the horizontal angle is 0 and the vertical angle is 0. Of course, when the reflector 11 is intentionally placed at a position shifted from the front of the radar device 9, the reference direction may be shifted from the origin direction. The reference direction may be set in advance using a model that has been confirmed to have no misalignment of the optical axis. In the present disclosure, the task of measuring the degree of misalignment of the optical axis is also referred to as optical axis inspection.

[0019] In the figure, Lt represents the distance from the radar device 9 to the radar inspection device 1 (hereinafter, test distance). The test distance (Lt) may be 1500 mm, 3000 mm, 4000 mm, etc. The optical axis inspection may be performed at multiple test distances (Lt). For example, the optical axis inspection may be performed by shifting the position of the radar device 9 back and forth by 10 mm each time within a range of 3000 mm ± 100 mm. The inspector may identify the degree of deviation of the optical axis based on the measurement results at multiple measurement points. The amount of deviation may be measured with an axis adjustment controller, which will be described later, connected to the radar device 9.

[0020] Incidentally, as shown by the dashed line in FIG. 1, the search wave emitted by the radar device 9 may be reflected by the floor surface and reach the reflector 11. The reflector 11 may also reflect the floor reflected wave toward the radar device 9. The floor reflected wave here refers to the search wave that is reflected by the floor surface and reaches the reflector 11. Such a floor reflected wave is noise in the optical axis inspection. The greater the intensity of the floor reflected wave, the lower the accuracy of the position estimation of the reflector 11 by the radar device 9 may be. In a test environment where the influence of the floor reflected wave is large, the measurement accuracy of the degree of deviation of the axis of the radar device 9 also deteriorates, and accurate axis adjustment may become difficult. The lower the mounting position of the radar device 9 on the vehicle 8, the greater the intensity of the floor reflected wave and the smaller the path difference between the floor reflected wave and the direct wave. When the path difference between the floor reflected wave and the direct wave becomes smaller, it becomes more difficult to separate the direct wave and the reflected wave. As a result, the lower the mounting position of the radar device 9, the more difficult it becomes to obtain accurate results of the optical axis inspection. On the other hand, in recent years, there has been an increase in cases where the radar device 9 is attached to the bumper. Due to the above and other circumstances, there is a demand for an optical axis inspection method capable of reducing the influence of floor reflected waves.

[0021] The radar inspection device 1 of this embodiment has been created based on the above circumstances, and includes a shielding unit 20 for shielding floor reflected waves, as shown in Fig. 2. Specifically, the radar inspection device 1 includes a reflector 11, a stand 12, a reflector fixing unit 13, and the shielding unit 20. The shielding unit 20 includes a shielding plate 21, a fixing unit 22, and an arm 23.

[0022] The reflector 11 is a three-sided corner reflector as shown in Fig. 3. That is, the reflector 11 is a metal body with an opening at the bottom of a triangular pyramid. The reflector 11 may also be called a corner cube or a retroreflector. The dimensions of the reflector 11 may be designed as appropriate. For example, the depth of the reflector 11 and the length of one side of the opening 111 may be designed as appropriate.

[0023] In reflector 11, the three slopes forming the triangular pyramid may be made of a metal such as aluminum. The reflector 11 may be configured so that the inner surface thereof reflects electromagnetic waves. The reflector 11 may be realized using a resin plated with a metal. In other embodiments, the reflector 11 may be a flat plate such as a metal plate. The reflector 11 may also be bowl-shaped.

[0024] The reflector 11 of this embodiment has the opening 111 as described above. The reflector 11 is fixed to the stand 12 with the opening 111 facing the vehicle 8. In this disclosure, the virtual plane formed by the opening 111 is referred to as the opening surface. The opening surface corresponds to the base surface of the triangular pyramid. The opening surface can also be considered as the reflective surface for the entire reflector 11. The reflector 11 is configured to emit the exploration wave that enters through the opening 111 in the opposite direction to the incident direction. In other words, the reflector 11 is configured to be capable of retroreflection.

[0025] In the present disclosure, the direction perpendicular to the opening surface and directed from the inside to the outside of the reflector 11 is referred to as the opening direction. The opening direction is the direction in which the reflector 11 faces. The opening direction corresponds to the reflection direction for the reflector 11. AD in the drawings represents the opening direction (in other words, the reflection direction). The opening direction / reflection direction for the reflector 11 may be interpreted as a resultant vector of the perpendicular vectors of the three reflecting surfaces of the three-hedral corner reflector. Note that, when the reflector 11 is a flat plate member (e.g., a metal plate), the expression "opening direction" below may be read as a direction perpendicular to the plate surface. Also, when the reflector 11 is a flat plate member, the expression "opening surface" may be interpreted as the reflection surface / surface of the flat plate member.

[0026] The stand 12 is a member for fixing the reflector 11 at a predetermined height. The stand 12 corresponds to a support. The stand 12 includes a base 121 and a pole 122. The base 121 is a plate-shaped member. The pole 122 is a rod-shaped member. The pole 122 is vertically erected on the upper surface of the base 121. Here, the vertical includes substantially vertical. The expression vertical may include a state inclined by about 10 degrees. The base 121 and the pole 122 may be integrally formed, or may be configured to be separable. The stand 12 is an optional element and may be omitted. The reflector 11 and the shielding unit 20 described later may be fixed to a wall, a shelf, or the like of the inspection site. In other words, the stand 12 may be a wall or the like. The shape of the stand 12 may be changed as appropriate.

[0027] The reflector fixing part 13 is a member that fixes the reflector 11 to the pole 122. The reflector fixing part 13 supports the reflector 11 so that the opening surface is vertical. The reflector fixing part 13 has a part that is attached to the reflector 11 and a part that is attached to the pole 122. The reflector fixing part 13 may be integrated with the reflector 11. The reflector fixing part 13 may be configured to be removable from the pole 122. Alternatively, the reflector fixing part 13 may be configured to be slidable along the pole 122. The reflector fixing part 13 may be fixed to the pole 122 by a screw. By changing the position of the reflector fixing part 13, the height position of the reflector 11 with respect to the floor surface can be adjusted. The reflector 11 may be disposed at the same height as the radar device 9. In other words, the radar inspection device 1 may be configured so that the reflector 11 and the radar device 9 face each other at the same height.

[0028] The shielding portion 20 is a module for reducing floor reflected waves from reaching the reflector 11. The shielding plate 21 is a plate-shaped member that reflects or absorbs radio waves (mainly exploration waves). For example, the shielding plate 21 may be a metal plate such as aluminum. The shielding plate 21 may be a non-metallic base material with aluminum foil or radio wave blocking film added to the surface. The base material may be any plate-shaped member such as a resin board, a wood board, cardboard, or a plaster board.

[0029] The shielding plate 21 may be rectangular as shown in FIG. 4. FIG. 4 is a top view of the radar inspection device 1. The stand 12 and the like are omitted from FIG. 4. The length of the shielding plate 21 in the front-rear direction, that is, the vertical length (L), may be 320 mm, 360 mm, or 400 mm. In the description of the configuration of the radar inspection device 1, the front may be interpreted as the opening direction. The front-rear direction for the shielding part 20 is a direction parallel to the opening direction. The larger the vertical length (L), the higher the shielding effect. However, the longer the vertical length (L), the higher the manufacturing cost. In addition, the larger the vertical length, the more storage space may be required. For these reasons, the vertical length (L) may be set to 250 mm to 420 mm.

[0030] The shielding plate 21 has a front end 211 and a rear end 212. The front end 211 is the forward-most edge of the shielding plate 21. The rear end 212 is the rear-most edge of the shielding plate 21. The length (L) may be understood as the distance from the rear end 212 to the front end 211.

[0031] The lateral width (W) of the shielding plate 21 may be larger than the width (Wr) of the reflector 11 by a predetermined amount. For example, the lateral width (W) may be set to a value corresponding to Wr + 100 mm. In other embodiments, the lateral width (W) of the shielding plate 21 may be the same as the width (Wr) of the reflector 11. Also, although the shielding effect decreases as compared with the case of W ≧ Wr, it may be set to W < Wr. Even when W < Wr, a part of the floor reflected wave can be shielded. As a result, the influence of the floor reflected wave on the optical axis inspection accuracy can be reduced. The lateral width (W) may be set to 100 mm or more. Note that Wr may be any value. For example, Wr may be 120 mm, 150 mm, 200 mm, etc.

[0032] Note that the shielding plate 21 does not necessarily have to be rectangular. As shown in FIG. 5, the shielding plate 21 may be trapezoidal. In the example shown in FIG. 5, a case is shown in which the shielding plate 21 has a trapezoidal shape where the front end portion 211 is shorter than the rear end portion 212. W1 shown in FIG. 5 indicates the width of the front end portion 211, and W2 indicates the width of the rear end portion 212. The values of W1 and W2 may be appropriately designed. In other embodiments, the width (W1) of the front end portion 211 may be larger than the width (W2) of the rear end portion 212. Additionally, the shielding plate 21 may be triangular or home base-shaped. The home base shape may be understood as a pentagonal shape in which an isosceles triangle having a base side of the same length as one side of a rectangle is connected.

[0033] The fixing portion 22 and the arm 23 are configurations for disposing the shielding plate 21 below the reflector 11. The fixing portion 22 is a member that is assembled to the pole 122 in the shielding portion 20. Similar to the reflector fixing portion 13, the fixing portion 22 may be configured to be removable from the pole 122. Also, the fixing portion 22 may be configured to be slidable along the pole 122. The fixing of the reflector fixing portion 13 to the pole 122 may be realized by screws or the like. The fixing portion 22 may be integrally formed with the arm 23. The fixing portion 22 may be a part of the arm 23.

[0034] The arm 23 is configured to dispose the shielding plate 21 a predetermined distance forward from the pole 122. The arm 23 fixes the shielding plate 21 so that the shielding plate 21 is parallel to the opening direction at a height position where the shielding plate 21 is a predetermined amount (dH) below the lower end 112 of the reflector 11 as shown in FIG. 6. dH is a parameter (hereinafter also referred to as a height offset amount) indicating the distance in the height direction from the lower end 112 to the shielding plate 21. The height offset amount (dH) may be any value such as 10 mm, 15 mm, or 20 mm. dH may be 0. From another perspective, the state in which the shielding plate 21 is parallel to the opening direction may be interpreted as the state in which the shielding plate 21 is parallel to the floor surface or parallel to a plane perpendicular to the pole 122.

[0035] The arm 23 also plays a role in adjusting the position of the shielding plate 21 in the front-rear direction. The rear end 212 of the shielding plate 21 may be located directly below the opening surface of the reflector 11, or may be located a predetermined amount (dX) forward of the opening surface. PA in the figure indicates the position of the opening surface. dX is a parameter (hereinafter also referred to as the rear end offset amount) indicating the position of the rear end 212 in the front-rear direction relative to the opening surface. The rear end offset amount (dX) may be expressed as a positive value when the rear end 212 is located forward of the opening surface. dX may be any value such as 10 mm, 15 mm, or 20 mm. A state where dX=0 corresponds to a state where the rear end 212 is located directly below the opening surface of the reflector 11. dX may be a negative value. A case where dX is negative means a state where the rear end 212 is located rearward of the opening surface of the reflector 11. In the present disclosure, the distance from the opening surface to the front end 211 is also referred to as the protrusion amount (PX).

[0036] The shielding plate 21 is disposed at a position where it blocks at least a part of the propagation path of the floor reflected wave, as shown in Fig. 7. The area shown by hatching in a dot pattern in Fig. 7 indicates the area through which the floor reflected wave that may be incident on the reflector 11 passes (hereinafter, the passing area). The passing area may be geometrically specified based on the height (H11) of the bottom end of the radar device 9, the height (H12) of the radar device 9 itself, the height (H21) of the bottom end 112, the height (H22) of the reflector 11 itself, and the test distance (Lt).

[0037] Ideally, the shielding plate 21 may have a size that completely blocks the floor reflected wave. However, the size of the shielding plate 21 may increase in order to completely block the floor reflected wave. The shielding plate 21 does not have to block all the floor reflected wave. Even if the shielding plate 21 blocks only a part (e.g., half) of the floor reflected wave, the effect of the floor reflected wave on the optical axis inspection can be reduced.

[0038] The shielding unit 20 may be configured so that the shielding plate 21 blocks one-third or more of the propagation path of the reflected wave. The arm 23 may be configured so that the shielding plate 21 is located at a predetermined relative position with respect to the reflector 11. The shielding unit 20 may be configured so that the protrusion amount (PX) is 300 mm or more. For example, the shielding plate 21 and the arm 23 may be configured so that PX=320 mm, dX=10 mm, and dH=10 mm. Of course, the value of each parameter may be changed appropriately. The value of each parameter may be changed by adjusting the dimensions of the shielding plate 21, the shape of the arm 23, the position of the fixing part 22, etc. According to this embodiment, as shown in FIG. 8, a part or all of the floor reflected wave is blocked by the shielding plate 21. Therefore, it is possible to reduce the risk of erroneously detecting the degree of deviation of the optical axis due to the floor reflected wave.

[0039] As a comparative example for suppressing floor reflected waves, as shown in FIG. 9, a configuration in which a partition 7 that absorbs or reflects the exploration wave is placed between the radar inspection device 1 and the radar device 9 (for example, in an intermediate position) is also possible. The partition 7 may have a height of about 100 mm to 200 mm. This comparative example also makes it possible to reduce the amount of floor reflected waves that reach the reflector 11. However, in the comparative example, dust and other debris accumulates near the partition 7. In contrast, the above embodiment has the advantage that debris is less likely to accumulate in the test environment.

[0040] Furthermore, the radar device 9 can be mounted in various positions, not limited to the center of the front end of the vehicle. In the comparative example, in order to accommodate the variety of mounting positions of the radar device 9, it may be necessary to install the partition 7 over a wide area of ​​the floor surface. On the other hand, according to the embodiment, it is possible to accommodate the variety of mounting positions by adjusting the shape / dimensions of the shielding plate 21.

[0041] Furthermore, the vehicle 8 that has completed the optical axis inspection may move forward to another location. At that time, the partition 7 becomes an obstacle for the vehicle 8. Therefore, in the comparative example, the inspector must remove the partition 7 every time the optical axis inspection for one vehicle is completed, which may reduce workability. In contrast, according to the embodiment, a three-dimensional object such as the partition 7 is not placed between the vehicle 8 and the radar inspection device 1. Therefore, the work of removing the three-dimensional object every time the optical axis inspection for one vehicle is completed does not occur. The embodiment has an advantage that the work efficiency for the optical axis inspection is higher than that of the comparative example.

[0042] As another comparative example, as shown in FIG. 10, a scattering mat 7a that scatters the search wave may be placed on the floor instead of the partition 7. For convenience, the inspection method / system shown in FIG. 9 is referred to as the first comparative example, and the inspection method / system shown in FIG. 10 is referred to as the second comparative example. The scattering mat 7a used in the second comparative example may have unevenness so as to scatter (diffusely reflect) the search wave. For example, the scattering mat 7a may have a plurality of protruding portions with a height of about 10 mm to 20 mm. The protruding portions may be metal bodies, or may be resin bodies with paint / sheets that can reflect the search wave added to their surfaces. The base material of the scattering mat 7a may be resin. The scattering mat 7a may be realized using a metal plate with an uneven surface.

[0043] The second comparative example can also reduce the amount of floor reflected waves that reach the reflector 11. However, the second comparative example has a problem that dirt is likely to accumulate on the unevenness of the scattering mat 7a. On the other hand, the scattering mat 7a is lower than the partition 7, so it is less likely to become an obstacle to the movement of the vehicle 8. In the second comparative example, there is no need to remove the scattering mat 7a every time the vehicle 8 is replaced. The second comparative example has an advantage that the work efficiency is higher than that of the first comparative example. In the second comparative example, an absorbing mat that absorbs radio waves may be used instead of the scattering mat 7a. The absorbing mat may be realized by using a resin mixed with a radio wave absorbing material. The radio wave absorbing material may be carbon, graphite, or the like. In the second comparative example, instead of placing the scattering mat 7a on the floor surface, the floor surface itself may be provided with unevenness.

[0044] As yet another comparative example (hereinafter, the third comparative example), an inspection method is assumed in which the reflector 11 is arranged at a position higher than the radar device 9 as shown in FIG. 11. The height difference between the reflector 11 and the radar device 9 may be 100 mm, 200 mm, 300 mm, etc. By arranging the reflector 11 at a position higher than the radar device 9, the difference in the path of the direct wave and the floor reflected wave becomes large, making it easier for the radar device 9 to distinguish between the direct wave and the floor reflected wave. In addition, the power of the unnecessary wave incident on the radar device 9 from the floor surface direction is also reduced. As a result, the influence of the floor reflected wave on the optical axis inspection accuracy can be reduced.

[0045] The first, second, and third comparative examples are all inspection methods / inspection systems newly (uniquely) created by the developers of the present disclosure to improve the optical axis inspection accuracy. These comparative examples are also included in the scope of the present disclosure. In addition, these comparative examples may be combined with the embodiment or the following modified examples. For example, the radar inspection device 1 used in the first, second, or third comparative example may have a shielding portion 20.

[0046] <Modification> When the shielding plate 21 is arranged parallel to the opening direction, the search wave from the radar device 9 may be reflected by the upper surface 213 of the shielding plate 21 and enter the reflector 11 as shown in Fig. 12. Such a reflected wave from the upper surface 213 may also affect the estimation accuracy of the optical axis direction (mainly the horizontal angle accuracy). The optical axis direction is the direction in which the optical axis extends.

[0047] In order to reduce such problems, a radio wave absorber 214 may be added to the upper surface 213 as shown in FIG. 13. The radio wave absorber 214 may be a radio wave absorbing sheet. The radio wave absorbing sheet may be a member formed into a sheet shape by mixing a radio wave absorbing material with rubber or resin. The radio wave absorbing material may be ferrite powder, carbon fiber, or the like. Since the radio wave absorber 214 absorbs the probing wave, it is possible to reduce the risk that the estimation accuracy of the optical axis direction will be deteriorated due to the reflected wave at the upper surface 213. The radio wave absorber 214 may have a structure in which radio wave absorbing elements having a pyramidal or wedge-shaped three-dimensional shape are densely arranged.

[0048] In addition, the upper surface 213 may be provided with projections and recesses as shown in Fig. 14. This structure is also expected to have the effect of scattering the exploration wave. The recesses / projections may be formed continuously in the lateral direction. The recesses or projections may be realized by making cuts in the upper surface 213 in the width direction.

[0049] The shielding unit 20 may include a shielding body 21a having a three-dimensional shape instead of the shielding plate 21. The shielding body 21a may have an inverted L-shaped cross section as shown in FIG. 15. Such a shielding body 21a may be logically / physically divided into a bottom 215 and a wall 216. The bottom 215 is a plate-like member parallel to the opening direction. The bottom 215 may be rectangular like the shielding plate 21. The wall 216 is a plate-like member perpendicular to the opening direction. The wall 216 stands at a right angle from the front end of the bottom 215. The wall 216 may also be rectangular. The height of the wall 216 may be, for example, 400 mm to 0 mm. The length of the bottom 215 in the front-rear direction may be 200 mm to 400 mm. The shielding body 21a has a front surface 2161 perpendicular to the floor surface. The shielding body 21a may be realized by bending a rectangular metal plate at a right angle. From one point of view, the shielding body 21a corresponds to a configuration in which a wall portion 216 is provided at the front end portion 211 of the shielding plate 21. Note that, in another embodiment, the shielding body 21a may be U-shaped in which the wall portions 216 are provided at both the front end and the rear end of the shielding plate 21.

[0050] The shielding body 21a is fixed to the pole 122 so that the upper end of the wall portion 216 is lower than the lower end portion 112. As described above, according to the configuration in which the wall portion 216 is provided at the front end of the shielding plate 21 (bottom portion 215), the wall portion 216 blocks the exploration wave traveling from the radar device 9 to the upper surface 213. This makes it possible to reduce the exploration wave transmitted by the radar device 9 from being incident on the reflector 11 via the upper surface 213. In other words, by providing the wall portion 216, the estimation accuracy of the optical axis direction can be improved.

[0051] The shielding plate 21 may be disposed at an angle to the opening direction as shown in Fig. 16. Specifically, the shielding plate 21 may be fixed to the pole 122 so that the rear end 212 is lower than the front end 211 by a predetermined amount (dZ). dZ is a parameter (hereinafter also referred to as the amount of inclination) indicating the distance in the height direction of the rear end 212 from the front end 211. The amount of inclination (dZ) may be any value, such as 10 mm, 15 mm, or 20 mm.

[0052] The inclination degree of the shielding plate 21 may be defined by an angle. For example, the inclination angle (θ) that the shielding plate 21 should take with respect to the opening direction may be 1°, 2°, 4°, etc. The inclination angle (θ) may be geometrically calculated from the test distance (Lt), the height (H12) of the radar device 9, and the protrusion amount (PX). For example, when the reflector 11 is disposed directly in front of the radar device 9 and H12≈H22, if a=Lt-PX and b=H12, the inclination angle θ may be set with arctan(b / a) as a guide. The horizontal distance from the radar device 9 to the front end 211 of the shielding plate 21 may be substituted for a. The height distance from the upper end of the radar device 9 to the lower end 112 of the reflector may be substituted for b. Approximate values ​​of 50 mm, 100 mm, and 150 mm may be applied to b. Considering the height offset amount (dH), b may be b=H12+dH. The height offset amount (dH) may be interpreted as the distance in the height direction between the front end portion 211 and the lower end portion 112. The above formula shows an example of the way of thinking when determining θ. θ may be designed appropriately.

[0053] For convenience, a configuration of the shielding part 20 in which the shielding plate 21 is tilted so that the rear end 212 is lower than the front end 211 is referred to as an inclined configuration. With the inclined configuration, the search wave is less likely to be reflected by the upper surface 213. Furthermore, with the inclined configuration, the risk that the search wave reflected by the upper surface 213 will be incident on the reflector 11 can be reduced. The above inclined configuration can also improve the estimation accuracy of the optical axis direction. Note that in the inclined configuration, a radio wave absorber 214 may be added to the upper surface of the shielding plate 21. Furthermore, in the inclined configuration, a radio wave absorber 214 may be added to the lower surface of the shielding plate 21.

[0054] The desired tilt angle (θ) is determined by the relative positional relationship between the radar device 9 and the reflector 11. Therefore, the tilt angle (θ) of the shielding plate 21 may be configured to be changeable. For example, as shown in FIG. 18, a rotating part 24 may be provided at the connection point between the arm 23 and the shielding plate 21. The rotating part 24 has a rotation axis parallel to the width direction. The rotating part 24 is configured to adjust the tilt angle (θ).

[0055] Incidentally, since the shielding portion 20 protrudes forward (in the opening / closing direction) beyond the reflector 11, it may take up more storage space than a configuration without the shielding portion 20. From this viewpoint, the shielding plate 21 may be configured to be foldable so as to reduce the length in the reflection direction. The shielding plate 21 may have one or more joints for folding. The joints may be realized using an axis parallel to the width direction. The shielding portion 20 may be configured to be able to change the length in the opening direction using a sliding mechanism such as a slide rail. For example, as shown in FIG. 17, the shielding plate 21 may be separated into a base portion 217 and a drawer portion 218, and the drawer portion 218 may be configured to be able to be drawn in the opening direction by a slide rail. A radio wave absorber may be provided at the front end of the base portion 217 and the drawer portion 218. As described above, the shielding plate 21 may be configured to be able to adjust the length in the opening direction by a folding method, a sliding method, or other method.

[0056] The arm 23 may be configured to be foldable. The arm 23 may include a joint portion 231. The joint portion 231 has a rotation axis parallel to the width direction. The joint portion 231 may be configured to be able to fold the arm 23 straight down. The arm 23 may have a plurality of joints. The shielding portion 20 may be configured to be foldable. This configuration makes it possible to reduce storage space.

[0057] The solid lines in Fig. 19 show a state in which the shielding part 20 is folded in the radar inspection device 1 into which the joint part 231 and the rotating part 24 are introduced. The dashed lines in Fig. 19 show an example of a posture when the radar inspection device 1 is in use. The angle of each joint may be configured to be fixable by a screw or the like.

[0058] Although the above describes an example in which the shielding part 20 is fixed to the pole 122, the method of fixing the shielding part 20 is not limited to this, and the shielding part 20 may be fixed to the reflector 11 as shown in Fig. 20. The arm 23 may be connected to the reflector 11. Alternatively, the arm 23 may be connected to the reflector fixing part 13. The reflector fixing part 13 and the fixing part 22 may be integrated.

[0059] In addition, a plurality of configurations included in the present disclosure may be appropriately combined and implemented. The embodiment and various modified examples may be combined with any of the first, second, and third comparative examples. For example, as shown in FIG. 21, an inclined configuration may be applied to the third comparative example. That is, the radar inspection device 1 may include a reflector 11 arranged at a higher position than the radar device 9 and a shielding plate 21 arranged at an angle. In this case, the shielding plate 21 may be arranged so as not to block the path of the direct wave. For example, the height offset amount (dH) may be set to 40 mm or 60 mm. The shielding plate 21 may be arranged at a position that does not block the direct wave and blocks part or all of the floor reflected wave. The dashed line shown in FIG. 21 indicates the range through which the direct wave passes. Also, the dashed line indicates the range through which the floor reflected wave passes.

[0060] <Optical axis inspection method> The optical axis inspection may be performed using an axis adjustment controller in addition to the radar inspection device 1. The axis adjustment controller may also be called an axis adjustment ECU (Electronic Control Unit). The axis adjustment controller may have a microcomputer including a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), an input / output circuit, and the like.

[0061] The optical axis inspection may be performed in the following steps: (1) installation of the vehicle 8, (2) position adjustment of the reflector 11, (3) position adjustment of the shielding plate 21, (4) connection of the axis adjustment controller, (5) acquisition of transmission and reception results, and (6) acquisition of the peak azimuth. (1) Installation of the vehicle may be moving the vehicle 8 equipped with the radar device 9 to a predetermined position in the work area in a predetermined orientation and stopping the vehicle. (2) Adjustment of the position of the reflector 11 may be arranging the reflector 11 in front of the radar device 9. In this case, the height of the reflector 11 may be set to the same height as the radar device 9. Adjustment of the position of the reflector 11 may include adjusting the height of the reflector 11 in addition to arranging the radar inspection device 1 at a predetermined position. Adjustment of the position of the reflector 11 may also include adjusting the pitch angle of the reflector 11 so that the opening plane of the reflector 11 is perpendicular to the floor. (3) The position adjustment of the shielding plate 21 may be to dispose the shielding plate 21 at a position that does not block the propagation path of the direct wave. The position adjustment of the shielding plate 21 may include adjusting the height of the shielding plate 21 and adjusting the inclination amount (dX) or inclination angle (θ) of the shielding plate 21.

[0062] (4) The axis adjustment controller may be connected by connecting a connector attached to the tip of a cable extending from the axis adjustment controller to an inspection connector provided on the vehicle 8. The inspection connector is connected to the radar device 9. The inspection connector may be provided under the dashboard of the vehicle 8, for example. (5) The transmission and reception results may be acquired by making the radar device 9 transmit and receive a search wave and acquiring the transmission and reception results. The transmission and reception results may be data indicating the reception strength for each direction. The reception strength for each direction may be obtained by performing FFT (Fast Fourier Transform) processing on the beat signal. The beat signal is a signal obtained by mixing the transmission signal and the reception signal in a mixer. (6) The peak direction may be acquired by identifying the peak direction, which is the direction in which the reception strength was the largest, from the transmission and reception results. In the optical axis inspection, the direction in which the radar device 9 detects the reflector 11 is the peak direction. The amount of deviation between the peak direction and the reference direction indicates the degree of deviation of the optical axis. (5) to (6) may be performed continuously and automatically by an examiner performing a predetermined operation on the axis adjustment controller.

[0063] <Additional remarks> The present disclosure also includes the following technical ideas.

[0064] [Technical thought 1] A reflector (11) that reflects radio waves; a shielding portion (20) disposed below the reflector for shielding radio waves traveling from the floor surface to the reflector.

[0065] [Technical thought 2] The reflector has a reflection direction set, The shielding portion includes a shielding plate (21) which is a plate-shaped member that reflects or absorbs radio waves, the shielding plate is parallel to the reflection direction, The radar inspection device according to Technical Idea 1, wherein the shielding plate has a portion that protrudes further in the reflection direction than the reflector.

[0066] [Technical thought 3] The radar inspection device according to Technical Idea 2, wherein a radio wave absorber (214) that absorbs radio waves is provided on an upper surface of the shielding plate.

[0067] [Technical thought 4] The radar inspection device according to Technical Idea 2, wherein the upper surface of the shielding plate is formed with projections and recesses for scattering radio waves.

[0068] [Technical thought 5] The reflector has a reflection direction set, The shielding portion includes a flat shielding plate (21), The shielding plate is a portion protruding in the reflection direction beyond the reflector; A front end (211) which is an end of the shielding plate located closest to the reflection direction; a rear end portion (212) opposite the front end portion, The radar inspection device according to any one of Technical Ideas 1 to 4, wherein the radar inspection device is installed at an angle to the reflection direction so that the rear end is lower than the front end.

[0069] [Technical Thought 6] The reflector has a reflection direction set, The shielding portion includes a flat shielding plate (21), the shielding plate has a portion that protrudes in the reflection direction beyond the reflector, The radar inspection device according to any one of Technical Ideas 1 to 5, wherein the shielding portion is provided with a rotating portion (24) for adjusting the angle of the shielding plate relative to the reflection direction.

[0070] [Technical Thought 7] The radar inspection device according to any one of Technical Ideas 2 to 6, wherein the shielding plate is configured so that its length in the reflection direction can be changed.

[0071] [Technical Thought 8] Further comprising a support (12) for supporting the reflector and the shielding portion, The shielding portion includes an arm (23) for fixing the shielding plate to the support body, The radar inspection device according to any one of Technical Ideas 2 to 7, wherein the arm is configured to be bendable.

[0072] [Technical Thought 9] The reflector has a reflection direction set, The shielding portion is A bottom portion (215) which is a plate-like member capable of reflecting or absorbing radio waves and is disposed parallel to the reflection direction; A wall portion (216) which is a plate-like member capable of reflecting or absorbing radio waves and is provided perpendicular to the bottom portion; The bottom portion has a front end portion which is an end portion located closest to the reflection direction, The wall portion is provided upright upward from the front end portion, The radar inspection device described in Technical Idea 1, wherein the shielding portion is fixed to the reflector or support body so that the upper end of the wall portion is lower than the lower end of the reflector. [Explanation of symbols]

[0073] 1 radar inspection device, 9 radar device, 11 reflector, 12 stand (support), 13 reflector fixing part, 20 shielding part, 21 shielding plate, 22 fixing part, 23 arm, 24 rotating part, 211 front end part, 212 rear end part, 213 top surface, 214 radio wave absorber, 215 bottom part, 216 wall part, 231 joint part

Claims

1. A reflector (11) that reflects radio waves; and a shielding portion (20) disposed below the reflector for shielding radio waves traveling from the floor surface to the reflector.

2. The reflector has a reflection direction set, The shielding portion includes a shielding plate (21) which is a plate-shaped member that reflects or absorbs radio waves, the shielding plate is parallel to the reflection direction, The radar inspection device according to claim 1 , wherein the shielding plate has a portion that protrudes further in the reflection direction than the reflector.

3. 3. The radar inspection device according to claim 2, wherein an electric wave absorber (214) for absorbing electric waves is provided on an upper surface of the shielding plate.

4. The radar inspection device according to claim 2 , wherein a plurality of recesses or protrusions are formed on an upper surface of the shielding plate.

5. The reflector has a reflection direction set, The shielding portion includes a flat shielding plate (21), The shielding plate is a portion protruding in the reflection direction beyond the reflector; A front end portion (211) which is an end portion of the shielding plate located closest to the reflection direction; a rear end portion (212) opposite the front end portion, 2. The radar inspection device according to claim 1, wherein the shielding plate is disposed at an angle to the reflection direction such that the rear end is lower than the front end.

6. The reflector has a reflection direction set, The shielding portion includes a flat shielding plate (21), the shielding plate has a portion that protrudes in the reflection direction beyond the reflector, 2. The radar inspection device according to claim 1, wherein the shielding portion includes a rotating portion for adjusting an angle of the shielding plate with respect to the reflection direction.

7. The radar inspection device according to claim 2 , wherein the shielding plate is configured so that a length in the reflection direction can be changed.

8. A support (12) for supporting the reflector and the shielding portion, The shielding portion includes an arm (23) for fixing the shielding plate to the support, The radar inspection device according to claim 2 , wherein the arm is configured to be bendable.

9. The reflector has a reflection direction set, The shielding portion is A bottom portion (215) which is a plate-like member capable of reflecting or absorbing radio waves and is arranged parallel to the reflection direction; A wall portion (216) which is a plate-like member capable of reflecting or absorbing radio waves and is provided perpendicular to the bottom portion; The bottom portion has a front end portion which is an end portion located closest to the reflection direction, The wall portion is provided upright upward from the front end portion, 2. The radar inspection device according to claim 1, wherein the shielding portion is fixed to the reflector or the support body such that an upper end of the wall portion is lower than a lower end of the reflector.

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