Radar inspection device

Abstract

This radar inspection device (1) includes a reflector (11), a stand (12), and a shielding part (20). The shielding part (20) includes a shielding plate (21). The shielding plate (21) is fixed below the reflector (11) by a fixing part (22) and an arm (23). The shielding plate (21) has a rectangular shape that is long in the reflection direction of the reflector (11). For example, the length of the shielding plate (21) is set to 250-420 mm. The shielding plate (21) is fixed below the reflector (11) so that the front end of the shielding plate protrudes further forward by a predetermined amount than an opening surface of the reflector (11).

Description

Radar Inspection Equipment CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application is based on Patent Application No. 2023-125810 filed in Japan on August 1, 2023, and the contents of the original application are incorporated by reference in their entirety.

[0002] The present disclosure relates to a radar inspection device used for adjusting the optical axis of a radar device.

[0003] Each radar device may have manufacturing errors. Furthermore, errors may occur in the position and orientation of the radar device when it is installed on a vehicle. A radar device cannot correctly identify the position of an object relative to the vehicle unless its optical axis is oriented in a pre-designed direction. Therefore, in a vehicle manufacturing plant, after the radar device is installed on 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 based on the reception intensity of a reflected wave from an axis adjustment reflector installed in front of the vehicle. The optical axis may also be referred to as the detection axis or radar axis. The axis adjustment reflector may also be referred to as a target.

[0004] JP 2020-134209 A JP 2005-98897 A

[0005] 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 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.

[0006] 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 erroneously detecting the direction in which the optical axis is pointing due to floor reflected waves.

[0007] One of the radar inspection devices disclosed herein includes a reflector that reflects radio waves, and a shielding section that is positioned below the reflector and that blocks radio waves traveling from the floor surface toward the reflector.

[0008] 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.

[0009] Note that 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.

[0010] 1 is a diagram for explaining an overview of a method for inspecting the optical axis of a radar device. FIG. 1 is a side view schematically showing the configuration of a radar device. FIG. 2 is an external perspective view showing the configuration of a reflector. FIG. 3 is a diagram showing the shape of a shielding plate. FIG. 4 is a diagram showing other examples of the shape of the shielding plate. FIG. 5 is a diagram for explaining the position of the shielding plate relative to the reflector. FIG. 6 is a diagram showing the path of floor-reflected waves that can be incident on the reflector. FIG. 7 is a diagram conceptually showing the effect of a shielding plate. FIG. 8 is a diagram showing a first comparative example. FIG. 9 is a diagram showing a second comparative example. FIG. 10 is a diagram showing a third comparative example. FIG. 11 is a diagram showing waves reflected by a shielding plate. FIG. 12 is a cross-sectional view showing a shielding plate having a radio wave absorber provided on its upper surface. FIG. 13 is a diagram showing a shielding plate whose upper surface has been treated to scatter exploration waves. FIG. 14 is a diagram showing another example of a shielding part. FIG. 15 is a diagram showing a form in which a shielding plate is arranged at an angle. FIG. 16 is a diagram showing an extendable shielding plate. FIG. 17 is a diagram showing a shielding part having a joint for accommodating the shielding plate. FIG. 18 is a diagram showing a state in which the shielding plate is accommodated. FIG. 19 is a diagram showing a configuration in which a shielding part is attached to a reflector. FIG. 20 is a diagram showing an inspection system in which a reflector is arranged a predetermined amount higher than a radar device in a radar inspection device equipped with a shielding part.

[0011] Hereinafter, embodiments 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 spirit of the present disclosure. Various modified examples may be appropriately combined as long as no technical contradictions arise. The present disclosure also includes configurations that are not explicitly shown but are formed by combining multiple modified examples. In the following description, components having the same function may be assigned the same reference numerals, and specific descriptions thereof may be omitted. When only a portion of a configuration is mentioned, descriptions provided elsewhere may apply to other portions. Some configurations shown in the drawings may be enlarged or reduced for convenience of explanation.

[0012] The configuration of the radar inspection device 1 will be described in detail below with reference to the drawings.

[0013] FIG. 1 is a diagram schematically illustrating an 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 quasi-millimeter wave band. The radar device 9 generates target information by analyzing the reception results of the search wave (hereinafter referred to as the reflected wave) reflected by a three-dimensional object present within the emission range and returning it. 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 distance and direction.

[0014] 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 angular range in which the radar device 9 can transmit a search wave or the center of the angular 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.

[0015] The radar device 9 may be mounted in the center of the front end of the vehicle 8, at the left and right corners, or at the top of the windshield, in order to obtain information about three-dimensional objects present mainly in the area ahead of the vehicle 8. The radar device 9 may be disposed behind the front emblem, in the center of the front bumper, or in the center of the front grille. The following description will be given assuming that the radar device 9 is mounted in the center of the front end of the vehicle 8. The center of the front end may be located midway between the left and right headlights. In other embodiments, the radar device 9 may be disposed in 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 disposed in the center of the rear bumper, at the left and right corners, at the top of the rear window, or the like. The following description may be modified as appropriate depending on the mounting location of the radar device 9.

[0016] As an example, the radar device 9 is mounted in a position where its optical axis coincides with the front direction of the vehicle. That is, when the radar device 9 is mounted in the 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 an error in manufacturing 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 a direction passing through the center of the vehicle 8 and heading from the rear end to the front end of the vehicle 8.

[0017] 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. The radar inspection device 1 is placed on the center line of the vehicle 8 (i.e., directly in front of the vehicle 8). As will be described later, 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.

[0018] The degree of deviation of the optical axis of the radar device 9 is measured by the radar device 9 actually transmitting and receiving search waves toward the reflector 11. The degree of deviation of the optical axis of the radar device 9 may be expressed as the difference between the detected direction of the reflector 11 and a predetermined reference direction. The detected direction may be data expressing the direction in which the reflector 11 exists using 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 detected direction may be expressed using the azimuth and the direction in which the optical axis extends as the origin. For the horizontal angle, an angle to the right of the vehicle may be expressed as a positive value, and an angle to the left may be expressed as a negative value. For the vertical angle, an angle in the upward direction may be expressed as a positive value, and an angle in the downward direction may be expressed as a negative value.

[0019] The reference direction is the detected direction of the reflector 11 when there is no optical axis misalignment. 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 where the horizontal angle is 0 and the vertical angle is 0. Of course, when the reflector 11 is intentionally placed in a position that is offset from the front of the radar device 9, the reference direction may deviate from the origin direction. The reference direction may be set in advance using a model that has been confirmed to have no optical axis misalignment. In the present disclosure, the task of measuring the degree of optical axis misalignment is also referred to as optical axis inspection.

[0020] In the figure, Lt represents the distance from the radar device 9 to the radar inspection device 1 (hereinafter referred to as the 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 increments within a range of 3000 mm ± 100 mm. The inspector may identify the degree of misalignment of the optical axis based on the measurement results at multiple measurement points. The amount of misalignment may be measured when an axis adjustment controller (described later) is connected to the radar device 9.

[0021] As shown by the dashed-dotted line in FIG. 1 , the search wave emitted by the radar device 9 may be reflected by the floor and reach the reflector 11. The reflector 11 may also reflect a floor-reflected wave toward the radar device 9. The floor-reflected wave here refers to a search wave that is reflected by the floor and reaches the reflector 11. Such a floor-reflected wave constitutes noise in the optical axis inspection. The greater the intensity of the floor-reflected wave, the lower the accuracy of the radar device 9's estimation of the position of the reflector 11. In a test environment where the influence of the floor-reflected wave is significant, the accuracy of measuring the degree of axis misalignment of the radar device 9 also deteriorates, making accurate axis adjustment difficult. The lower the radar device 9 is installed 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. The smaller the path difference between the floor-reflected wave and the direct wave, the more difficult it is to separate the direct wave from the reflected wave. As a result, the lower the radar device 9 is installed, the more difficult it is to obtain accurate optical axis inspection results. On the other hand, in recent years, there has been an increasing number of 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 that can reduce the influence of floor reflected waves.

[0022] 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.

[0023] The reflector 11 is a three-sided corner reflector as shown in FIG. 3 . That is, the reflector 11 is a metal body with a triangular pyramid shape and an opening at the bottom. The reflector 11 may also be called a corner cube or a reflective reflector. The dimensions of the reflector 11 may be designed as appropriate. The depth of the reflector 11 and the length of one side of the opening 111 may be designed as appropriate.

[0024] In the reflector 11, the three slopes forming the triangular pyramid may be made of a metal such as aluminum. The reflector 11 may be configured such that the inner surface thereof reflects electromagnetic waves. The reflector 11 may be realized using a resin plated with 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.

[0025] 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 imaginary plane formed by the opening 111 is referred to as the opening surface. The opening surface corresponds to the base of the triangular pyramid. The opening surface can also be considered as a reflective surface for the entire reflector 11. The reflector 11 is configured to emit the probing wave that enters through the opening 111 in the direction opposite to the incident direction. In other words, the reflector 11 is configured to be retroreflective.

[0026] In the present disclosure, the direction perpendicular to the opening surface and extending 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 of the reflector 11. AD in the drawings represents the opening direction (in other words, the reflection direction). The opening direction / reflection direction of the reflector 11 may be interpreted as a resultant vector of the perpendicular vectors of the three reflecting surfaces of the trihedral 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 interpreted as a direction perpendicular to the plate surface. Furthermore, 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.

[0027] 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 erected vertically on the upper surface of the base 121. Here, "vertical" includes "approximately vertical." The expression "vertical" may also include a state inclined by about 10 degrees. The base 121 and the pole 122 may be formed integrally, or may be configured to be separable. Note that the stand 12 is an optional element and may be omitted. The reflector 11 and the shielding unit 20, which will be described later, may be fixed to a wall, shelf, etc. at the inspection site. In other words, the stand 12 may be a wall, etc. The shape of the stand 12 may be changed as appropriate.

[0028] 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 detachable 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 with screws. The height position of the reflector 11 with respect to the floor surface can be adjusted by changing the position of the reflector fixing part 13. The reflector 11 may be disposed at the same height as the radar device 9. That is, 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.

[0029] The shielding unit 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 search waves). The shielding plate 21 may be a metal plate such as aluminum. The shielding plate 21 may also be a non-metallic base material with aluminum foil or radio wave blocking film attached to the surface. The base material may be any plate-shaped member such as a resin board, wood board, cardboard, or gypsum board.

[0030] 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 other components are not shown in FIG. 4. The vertical length (L), which is the length in the front-to-rear direction of the shielding plate 21, may be 320 mm, 360 mm, or 400 mm. In describing the configuration of the radar inspection device 1, the "front" may be interpreted as the opening direction. The front-to-rear direction for the shielding unit 20 is the direction parallel to the opening direction. The greater the vertical length (L), the greater the shielding effect. However, the longer the vertical length (L), the higher the manufacturing cost. Furthermore, the greater the vertical length, the greater the storage space required. For these reasons, the vertical length (L) may be set to 250 mm to 420 mm.

[0031] The shielding plate 21 has a front end 211 and a rear end 212. The front end 211 is the edge located most forward of the shielding plate 21. The rear end 212 is the edge located most rearward of the shielding plate 21. The length (L) may be interpreted as the distance from the rear end 212 to the front end 211.

[0032] The width (W) of the shielding plate 21 may be larger than the width (Wr) of the reflector 11 by a predetermined amount. The width (W) may be set to a value equivalent to Wr + 100 mm. In other embodiments, the width (W) of the shielding plate 21 may be the same as the width (Wr) of the reflector 11. Furthermore, although the shielding effect will be reduced compared to when W≧Wr, it may be set to W<Wr. Even when W<Wr, it is possible to shield a portion of the floor reflected waves. Consequently, it is possible to reduce the influence of the floor reflected waves on the optical axis inspection accuracy. The width (W) may be set to 100 mm or more. Note that Wr may be any value. Wr may be 120 mm, 150 mm, 200 mm, etc.

[0033] The shielding plate 21 does not necessarily have to be rectangular. As shown in FIG. 5, the shielding plate 21 may be trapezoidal. The example shown in FIG. 5 illustrates a case in which the shielding plate 21 has a trapezoidal shape in which the front end 211 is shorter than the rear end 212. W1 and W2 shown in FIG. 5 indicate the width of the front end 211 and the width of the rear end 212, respectively. The values ​​of W1 and W2 may be designed as appropriate. In other embodiments, the width (W1) of the front end 211 may be larger than the width (W2) of the rear end 212. Alternatively, the shielding plate 21 may be triangular or home-base shaped. A home-base shape may be interpreted as a pentagon formed by connecting one side of a rectangle to an isosceles triangle having a base the same length as the side.

[0034] The fixing part 22 and the arm 23 are components for positioning the shielding plate 21 below the reflector 11. The fixing part 22 is a member that is attached to the pole 122 in the shielding part 20. Like the reflector fixing part 13, the fixing part 22 may be configured to be detachable from the pole 122. The fixing part 22 may also be configured to be slidable along the pole 122. The reflector fixing part 13 may be fixed to the pole 122 by a screw or the like. The fixing part 22 may be formed integrally with the arm 23. The fixing part 22 may be part of the arm 23.

[0035] The arm 23 is configured to position the shielding plate 21 a predetermined distance forward from the pole 122. The arm 23 is fixed 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 indicating the distance in the height direction from the lower end 112 to the shielding plate 21 (hereinafter also referred to as a height offset). The height offset (dH) may be any value, such as 10 mm, 15 mm, or 20 mm. dH may also 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 a plane perpendicular to the pole 122.

[0036] The arm 23 also serves to adjust the position of the shielding plate 21 in the front-to-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 distance (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) that indicates the position of the rear end 212 in the front-to-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 also be a negative value. A negative dX means that 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).

[0037] As shown in Fig. 7, 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. In Fig. 7, the area indicated by hatching in a dot pattern indicates the area through which the floor-reflected wave that may be incident on the reflector 11 passes (hereinafter referred to as the passing area). The passing area may be geometrically specified based on the height (H11) of the lower end of the radar device 9, the height (H12) of the radar device 9 itself, the height (H21) of the lower end 112, the height (H22) of the reflector 11 itself, and the test distance (Lt).

[0038] Ideally, the shielding plate 21 may have a size that completely blocks the floor reflected waves. However, the size of the shielding plate 21 may be increased to completely block the floor reflected waves. The shielding plate 21 does not have to block all of the floor reflected waves. Even if the shielding plate 21 blocks only a portion (e.g., half) of the floor reflected waves, the influence of the floor reflected waves on the optical axis inspection can be reduced.

[0039] 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 positioned 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. 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 values ​​of each parameter may be changed as appropriate. The values ​​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 portion 22, etc. According to this embodiment, as shown in FIG. 8 , part or all of the floor reflected wave is blocked by the shielding plate 21. This reduces the risk of erroneous detection of the degree of misalignment of the optical axis due to the floor reflected wave.

[0040] As a comparative example for suppressing floor reflected waves, a configuration is also possible in which a partition 7 that absorbs or reflects the search wave is placed between the radar inspection device 1 and the radar device 9 (for example, in an intermediate position), as shown in FIG. 9 . The partition 7 may have a height of approximately 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 accumulate near the partition 7. In contrast, the above embodiment has the advantage that debris is less likely to accumulate in the test environment.

[0041] Furthermore, the radar device 9 can be mounted in various positions, not just 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.

[0042] Furthermore, after the optical axis inspection is completed, the vehicle 8 can 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 can reduce work efficiency. 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 the advantage of higher work efficiency for optical axis inspection than the comparative example.

[0043] Another comparative example is an inspection method in which a scattering mat 7a that scatters the probe wave is placed on the floor instead of the partition 7, as shown in FIG. 10 . For convenience, the inspection method / inspection system shown in FIG. 9 will be referred to as the first comparative example, and the inspection method / inspection system shown in FIG. 10 will be referred to as the second comparative example. The scattering mat 7a used in the second comparative example may have irregularities to scatter (diffusely reflect) the probe wave. The scattering mat 7a may have multiple protrusions with a height of approximately 10 mm to 20 mm. The protrusions may be metal or may be a resin body with a paint / sheet applied to its surface that can reflect the probe wave. The base material of the scattering mat 7a may be resin. The scattering mat 7a may be realized using a metal plate with an irregular surface.

[0044] The second comparative example can also reduce the amount of floor-reflected waves reaching the reflector 11. However, the second comparative example still has the problem that dust easily accumulates in the unevenness of the scattering mat 7a. On the other hand, the scattering mat 7a is shorter 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 the advantage of higher work efficiency than the first comparative example. Note that 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 made of a resin mixed with a radio wave absorbing material. The radio wave absorbing material may be carbon, graphite, or the like. Furthermore, in the second comparative example, instead of placing the scattering mat 7a on the floor surface, the floor surface itself may be uneven.

[0045] As another comparative example (hereinafter referred to as the third comparative example), an inspection method is assumed in which the reflector 11 is placed at a higher position than the radar device 9, as shown in FIG. 11 . The difference in height between the reflector 11 and the radar device 9 may be 100 mm, 200 mm, 300 mm, or the like. By placing the reflector 11 at a higher position than the radar device 9, the difference in the paths of the direct wave and the floor-reflected wave becomes larger, 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 unwanted 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.

[0046] The first, second, and third comparative examples are all inspection methods / systems newly (originally) created by the developers of the present disclosure to improve the accuracy of optical axis inspection. These comparative examples are also included in the scope of the present disclosure. Furthermore, these comparative examples may be combined with the embodiment or the following modified examples. The radar inspection device 1 used in the first, second, or third comparative example may have a shielding portion 20.

[0047] <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.

[0048] To alleviate 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 sheet-shaped member formed 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. Because the radio wave absorber 214 absorbs the probing waves, it is possible to reduce the risk of the estimation accuracy of the optical axis direction being degraded by the waves reflected by 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.

[0049] The upper surface 213 may also 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 horizontal direction. The recesses or projections may be realized by cutting notches in the upper surface 213 in the width direction.

[0050] 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-to-rear direction may be 200 mm to 400 mm. The shielding body 21a has a front surface 2161 that is perpendicular to the floor surface. The shield 21a may be realized by bending a rectangular metal plate at a right angle. From one perspective, the shield 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 shield 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.

[0051] 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 search wave traveling from the radar device 9 toward the upper surface 213. This reduces the likelihood of the search wave transmitted by the radar device 9 being incident on the reflector 11 via the upper surface 213. In other words, providing the wall portion 216 improves the accuracy of estimating the optical axis direction.

[0052] The shielding plate 21 may be disposed at an angle with respect 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 tilt) that indicates the distance in the height direction of the rear end 212 relative to the front end 211. The amount of tilt (dZ) may be any value, such as 10 mm, 15 mm, or 20 mm.

[0053] The degree of inclination of the shielding plate 21 may be defined by an angle. The inclination angle (θ) of the shielding plate 21 relative 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, if the reflector 11 is disposed directly in front of the radar device 9 and H12≈H22, then, assuming a = Lt - PX and b = H12, the inclination angle θ may be set using 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 vertical distance from the top end of the radar device 9 to the bottom end 112 of the reflector may be substituted for b. Approximate values ​​of 50 mm, 100 mm, or 150 mm may be applied to b. Considering the height offset amount (dH), b may be expressed as 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 how to determine θ. θ may be designed as appropriate.

[0054] For convenience, a configuration of the shielding unit 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 an inclined configuration, the search wave is less likely to be reflected by the upper surface 213. Furthermore, with an inclined configuration, the risk of the search wave reflected by the upper surface 213 being incident on the reflector 11 can be reduced. The above inclined configuration also improves the accuracy of estimating 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. Also, in the inclined configuration, a radio wave absorber 214 may be added to the lower surface of the shielding plate 21.

[0055] 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. 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 allow the tilt angle (θ) to be adjusted.

[0056] 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 perspective, the shielding plate 21 may be configured to be foldable so as to reduce its length in the reflection direction. The shielding plate 21 may have one or more joints for folding. The joints may be realized using axes parallel to the width direction. Furthermore, the shielding portion 20 may be configured so that its length in the opening direction can be changed using a sliding mechanism such as a slide rail. 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 so that it can be drawn in the opening direction using a slide rail. Radio wave absorbers may be provided at the front ends of the base portion 217 and the drawer portion 218. As described above, the shielding plate 21 may be configured so that its length in the opening direction can be adjusted by a folding method, a sliding method, or other method.

[0057] The arm 23 may be configured to be bendable. The arm 23 may include a joint 231. The joint 231 has a rotation axis parallel to the width direction. The joint 231 may be configured to bend the arm 23 straight down. The arm 23 may have multiple joints. The shielding unit 20 may be configured to be foldable. This configuration makes it possible to reduce storage space.

[0058] The solid lines in Fig. 19 indicate a state in which the shielding unit 20 is folded in the radar inspection device 1 into which the joint unit 231 and the rotating unit 24 are installed. The dashed lines in Fig. 19 indicate an example of the posture of the radar inspection device 1 when in use. The angle of each joint may be configured to be fixable with a screw or the like.

[0059] Although the above describes an example in which the shielding unit 20 is fixed to the pole 122, the method of fixing the shielding unit 20 is not limited to this, and the shielding unit 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 unit 13. The reflector fixing unit 13 and the fixing unit 22 may be integrated.

[0060] In addition, multiple configurations included in the present disclosure may be implemented in appropriate combination. The embodiment and various modified examples may be combined with any of the first, second, and third comparative examples. As illustrated 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 positioned higher than the radar device 9 and a shielding plate 21 positioned at an angle. In this case, the shielding plate 21 may be positioned so as not to block the path of the direct wave. The height offset (dH) may be set to 40 mm or 60 mm. The shielding plate 21 may be positioned so as not to block the direct wave but to block some or all of the floor-reflected wave. The dashed line in FIG. 21 indicates the range through which the direct wave passes. The dashed line indicates the range through which the floor-reflected wave passes.

[0061] <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), ROM (Read Only Memory), RAM (Random Access Memory), input / output circuits, etc.

[0062] The optical axis inspection may be performed in the following steps: (1) installing the vehicle 8, (2) adjusting the position of the reflector 11, (3) adjusting the position of the shielding plate 21, (4) connecting the axis adjustment controller, (5) obtaining transmission and reception results, and (6) obtaining the peak azimuth. (1) Installing the vehicle may involve moving the vehicle 8 equipped with the radar device 9 to a predetermined position in the work area in a predetermined orientation and parking it there. (2) Adjusting the position of the reflector 11 may involve placing 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. Adjusting the position of the reflector 11 may include adjusting the height of the reflector 11 in addition to placing the radar inspection device 1 at a predetermined position. Adjusting 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 tilt amount (dX) or tilt angle (θ) of the shielding plate 21.

[0063] (4) The axis adjustment controller may be connected by connecting a connector attached to the end 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, for example, under the dashboard of the vehicle 8. (5) The transmission and reception results may be obtained by having the radar device 9 transmit and receive search waves 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 transmitted signal and the received signal in a mixer. (6) The peak direction may be obtained by identifying the peak direction, which is the direction in which the reception strength was strongest, 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. Steps (5) and (6) may be performed continuously and automatically by the examiner performing a predetermined operation on the axis adjustment controller.

[0064] <Additional Remarks> The present disclosure also includes the following technical ideas.

[0065] [Technical Idea 1] A radar inspection device including: 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 a floor surface toward the reflector.

[0066] [Technical Idea 2] The radar inspection device according to Technical Idea 1, wherein a reflection direction is set for the reflector, the shielding portion includes a shielding plate (21) that is a plate-shaped member that reflects or absorbs radio waves, the shielding plate is parallel to the reflection direction, and the shielding plate has a portion that protrudes further in the reflection direction than the reflector.

[0067] [Technical Concept 3] The radar inspection device according to Technical Concept 2, wherein a radio wave absorber (214) that absorbs radio waves is provided on the upper surface of the shielding plate.

[0068] [Technical Concept 4] The radar inspection device according to Technical Concept 2, wherein a plurality of recesses or protrusions are formed on the upper surface of the shielding plate.

[0069] [Technical Idea 5] A radar inspection device according to any one of Technical Ideas 1 to 4, wherein the reflector has a set reflection direction, the shielding portion includes a flat shielding plate (21), the shielding plate has a portion that protrudes further in the reflection direction than the reflector, a front end (211) that is the end of the shielding plate that is located closest to the reflection direction, and a rear end (212) that is the end opposite to the front end, and the shielding plate is installed at an angle with respect to the reflection direction so that the rear end is lower than the front end.

[0070] [Technical Idea 6] A radar inspection device according to any one of Technical Ideas 1 to 5, wherein a reflection direction is set for the reflector, the shielding portion includes a flat shielding plate (21), the shielding plate has a portion that protrudes further in the reflection direction than the reflector, and the shielding portion is provided with a rotating portion (24) for adjusting the angle of the shielding plate with respect to the reflection direction.

[0071] [Technical Concept 7] The radar inspection device according to any one of Technical Concepts 2 to 6, wherein the shielding plate is configured so that the length in the reflection direction can be changed.

[0072] [Technical Idea 8] The radar inspection device according to any one of Technical Ideas 2 to 7, further comprising a support (12) for supporting the reflector and the shielding portion, the shielding portion comprising an arm (23) for fixing the shielding plate to the support, and the arm being configured to be bendable.

[0073] [Technical Idea 9] A reflection direction is set for the reflector, and the shielding portion comprises: a bottom (215) that is a plate-like member capable of reflecting or absorbing radio waves and is arranged parallel to the reflection direction; and a wall (216) that is a plate-like member capable of reflecting or absorbing radio waves and is arranged perpendicular to the bottom, and the bottom has a front end that is the end located closest to the reflection direction, and the wall is erected upward from the front end, and the shielding portion is fixed to the reflector or a support body so that the upper end of the wall is lower than the lower end of the reflector. This is a radar inspection device according to Technical Idea 1.

Claims

1. A radar inspection device comprising: 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.

2. A radar inspection device as described in claim 1, wherein the reflector has a set reflection direction, 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, and the shielding plate has a portion that protrudes further in the reflection direction than the reflector.

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

5. A radar inspection device as described in claim 1, wherein the reflector has a set reflection direction, the shielding portion includes a flat shielding plate (21), the shielding plate has a portion that protrudes further in the reflection direction than the reflector, a front end (211) which is the end of the shielding plate located furthest toward the reflection direction, and a rear end (212) which is the end opposite to the front end, and the shielding plate is installed at an angle to the reflection direction so that the rear end is lower than the front end.

6. A radar inspection device as described in claim 1, wherein the reflector has a set reflection direction, the shielding portion includes a flat shielding plate (21), the shielding plate has a portion that protrudes in the reflection direction beyond the reflector, and the shielding portion is provided with a rotating portion (24) for adjusting the angle of the shielding plate with respect to the reflection direction.

7. A radar inspection device according to any one of claims 2 to 6, wherein the shielding plate is configured so that its length in the reflection direction can be changed.

8. A radar inspection device as described in any one of claims 2 to 6, further comprising a support (12) for supporting the reflector and the shielding portion, the shielding portion comprising an arm (23) for fixing the shielding plate to the support, and the arm being configured to be bendable.

9. A radar inspection device as described in claim 1, wherein the reflector has a set reflection direction, the shielding portion comprises: a bottom (215) which is a plate-like member capable of reflecting or absorbing radio waves and is arranged parallel to the reflection direction, and a wall (216) which is a plate-like member capable of reflecting or absorbing radio waves and is arranged perpendicular to the bottom, the bottom portion has a front end which is the end located closest to the reflection direction, the wall portion is erected upward from the front end portion, and the shielding portion is fixed to the reflector or a support body so that the upper end of the wall portion is lower than the lower end of the reflector.

Images