JP4450835B2 - Radar reflector - Google Patents

Description

  The present invention relates to a radar reflection device that is mounted on a vehicle traveling ahead and reflects information related to the shape of the vehicle to an in-vehicle radar device mounted on another rear vehicle.

The above-mentioned on-vehicle radar device is a sensor used to monitor the periphery of the vehicle, emits radio waves from the on-vehicle radar device to the periphery of the vehicle, and detects obstacles around the vehicle from the reflected waves. Is possible.
Information that can be detected by the in-vehicle radar device includes a relative distance to a front obstacle, a relative speed, or a position direction of the obstacle.
As an application of the above-mentioned radar for in-vehicle use, an automatic speed control system that realizes auto-cruise control or a vehicle that detects the possibility of a collision with an obstacle and alerts the driver and determines that collision cannot be avoided. There is already known a pre-crash safety system that controls to protect people on the road.

The on-vehicle radar device obtains the position information (angle) of the obstacle from the intensity distribution peak of the radio wave reflected by the obstacle at a certain angle and determines whether the obstacle in front is a car. As a matter of determination, when a plurality of same targets are detected, it is necessary to perform pairing processing for determining whether or not the targets are the same.
In the in-vehicle radar device, the reflected intensity distribution of the radio wave of the front vehicle is not only influenced by the relative position (distance and angle) with the front vehicle, but also becomes unstable due to the shape of the rear part of the front vehicle. For this reason, it is difficult to obtain a uniform reflection intensity distribution on the rear plane of the vehicle, and there is a limit to the pairing process.

Conventional techniques such as those shown in Patent Document 1 to Patent Document 4 have been proposed to deal with such problems.
For example, in Patent Document 1, a rear bumper and a rear combination at the rear of a vehicle are obtained so that a reflected wave having a predetermined intensity can be stably obtained without being greatly affected by the relative position (distance or angle) with the vehicle ahead and the body shape of the vehicle ahead. A lamp or the like provided with a three-surface or two-surface corner reflector to reflect in the incident direction of radio waves is disclosed.
Japanese Patent Application Laid-Open No. 2004-228561 discloses means for integrally mounting a radio wave reflector effective for a 50 to 100 GHz radio wave radiated from an in-vehicle radar device together with an optical reflector.
In Patent Document 3, a radar reflector that reflects radio waves emitted from an in-vehicle radar device is provided in the tread portion of an automobile tire, and it is determined whether the vehicle in front is an automobile, and the traveling state of the preceding vehicle A technique for detecting the above is known.
Patent Document 4 is an example of Patent Document 2, but discloses a technique of disposing a radio wave reflector inside a mall provided around the vehicle.

JP 2000-103283 A Japanese Patent Laid-Open No. 11-248836 JP 2000-326711 A JP-A-8-181535

As described above, in the existing technology, there is a technology of providing a reflector structure that reflects radio waves on the own vehicle. According to these techniques, a certain vehicle width of the forward vehicle can be predicted, and it can be seen that the same target is obtained from the detection signal group in the angular direction of the on-vehicle radar device.
The reflector for reflecting in the direction in which the radio wave enters is composed of two or three metal plates, and they are combined so that they are 90 degrees from each other. The incident wave depends on the number of reflector surfaces. Although it is different, it reflects through two or three reflections.

When detecting the relative distance to the obstacle from the time of the reflected wave that the incident wave is reflected back from the obstacle, such as in-vehicle radar equipment, the larger the reflector opening surface size, the more As a result, variation in the detection distance also increases.
If a large reflector is simply provided, the incident angle to the reflector is different depending on the relative positional relationship between the front vehicle and the rear vehicle, so that the distance variation increases and the distance performance of the radar is deteriorated. In addition, as the distance is shorter, the variation is larger and the distance accuracy is deteriorated.
In systems such as LSF (Low Speed Following) and Full Speed Range ACC (FSRA), which can follow the preceding vehicle at low speeds, distance accuracy, vehicle edge and width Detection accuracy is required.

As described above, when reflectors are provided at both ends of the rear of the vehicle, the variation becomes larger as the distance is shorter, and the distance accuracy is adversely affected. From this point of view, it can be seen that it is effective to detect the central portion of the vehicle in order to improve edge detection and vehicle width detection accuracy.
However, when detecting the central part of the vehicle, there are various things such as a license plate, a truck handle, or a garnish part for decorating the peripheral part at the center in the vehicle width direction of the rear part of a general passenger car, and the body shape is also It depends on the vehicle type. In addition, the body shape is uneven, and it is difficult to obtain a uniform reflected wave intensity distribution as a flat surface. Therefore, the detection level of the in-vehicle radar device varies, and the in-vehicle radar device stabilizes the vehicle ahead. There is a possibility that the target cannot be detected and a target loss or erroneous detection on the detection processing side may be caused. In addition, in the case of a general passenger car, the fact that the area of the metal part that can be reflected is smaller than that of a large vehicle and that the rear windshield occupies about half of the rear area of the vehicle is also one factor. Therefore, there is a problem that the reflecting surface must be effectively provided in a limited space.
In addition, in the pre-crash system, it is desirable to detect the amount of lateral offset between the host vehicle and the preceding vehicle when more advanced control is to be realized, but the reflection part of the preceding vehicle changes depending on the situation. There is a problem that the offset amount cannot be obtained accurately.
As shown in FIG. 1, the present invention is to provide a radar reflection device that improves the above-described problems by providing a reflector structure on various members arranged in the center in the vehicle width direction at the rear of the vehicle. .

A radar reflecting device according to the present invention includes a rear wiper arm for wiping the rear window glass, and a radar reflecting device provided in a rear wiper device disposed at the center in the vehicle width direction at the rear of the vehicle . A transmissive member that transmits radio waves emitted from another rear vehicle, and a reflector portion that is provided inside the transmissive member and reflects the transmitted radio waves toward the other rear vehicle are provided, and the reflector portion is provided as the rear wiper. It is intended to move together with the arm .

According to the radar reflection device of the present invention, the reflector structure that efficiently reflects the radio wave in the direction opposite to the direction in which the radio wave is incident is provided on the rear wiper arm of the rear wiper device that is disposed at the center in the vehicle width direction at the rear of the vehicle. Therefore, even in a limited space, a reflective surface is effectively provided, and the reflected wave intensity distribution at the center in the vehicle width direction at the rear of the vehicle can be obtained uniformly. The level variation can be reduced.
In addition, by providing a reflector structure in the rear wiper arm at the center in the vehicle width direction at the rear of the vehicle, radio waves emitted from the in-vehicle radar device provided in the vehicle traveling behind are almost perpendicular to the opening surface of the reflector. The propagation path of the radio wave incident on and reflected by is substantially the depth of the reflector (shortest path).
Moreover , even with a small number of reflecting surfaces such as the rear part of a general passenger car, the in-vehicle radar device can stably detect the vehicle ahead, and target loss and false detection on the detection processing side can be reduced.
Furthermore, the detection distance data obtained at the center in the vehicle width direction has less variation than the detection distance data obtained by the reflectors provided at both ends of the vehicle, so that the distance accuracy can be improved.

When the position information at both ends of the vehicle and the position information obtained at the center in the vehicle width direction of the present invention are used in combination, it is possible to improve the accuracy of pairing processing, edge detection and vehicle width detection of the on-vehicle radar device. (Low Speed Following), system reliability such as Full Speed Range ACC (FSRA, Full Speed Range ACC) is improved.
Also, in pre-crash systems, etc., the lateral offset amount of the host vehicle and the preceding vehicle can be accurately identified, and the accuracy of the vehicle width estimation is improved, so finer control can be realized and a much safer system can be realized. Can be built. Therefore, it is possible to reduce discomfort and discomfort to the driver and passengers that may occur when the system state transitions.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a rear view of the rear part of the vehicle in which all the embodiments of the present invention are shown. Each embodiment is shown in FIG. 2 and subsequent figures, and the same reference numerals denote the same or corresponding parts in the respective drawings.

Embodiment 1 FIG.
FIG. 2 is a perspective view showing the rear wiper device 1 according to the first embodiment of the present invention.
In FIG. 2, a rear wiper device 1 includes a rear wiper arm 7 constituting a rear wiper device 1 dedicated for an automobile, a rear wiper pivot shaft 8 serving as a rotation axis of the rear wiper arm 7, a rear wiper pivot shaft 8 and a drive. A casing 9 for housing a drive unit (not shown) for controlling the rotation of the shaft, a protective cover 10, a clamping fixture 11, and the like are included.
The rear wiper arm 7 is in contact with the rear window glass surface and is pivotally supported by a rear wiper pivot shaft 8 so as to wipe off water droplets and dirt adhering to the glass surface, and a drive unit (not shown) via the rear wiper pivot shaft 8. Control driven. In addition, the rubber element is provided in the part which touches the glass surface of the rear wiper arm 7, The structure which does not damage a glass surface, for example, the thing made from rubber | gum is used for this site | part.
The casing portion 9 is clamped and fixed to the vehicle body 12 by a clamp fixture 11.

更に、このリフレクタ構造１３と対向する車ボディ１２部分は、凹凸形状部分であっても電波の透過性の良い部材、例えばABS樹脂、アクリル樹脂で構成することで反射強度分布バラツキを抑え、一様な強度分布を得ることができる様になされている。 The rear wiper device 1 is equipped with a reflector structure 13.
In other words, the vehicle-mounted radar device provided in the vehicle traveling behind stably obtains the reflected wave from the center of the rear portion of the front vehicle, so that the vehicle body 12 (or rear window glass) side of the casing portion 9 As shown in FIG. 2, a reflector structure 13 for reflecting radio waves (in the downward direction of the arrow) is provided. This reflector is composed of two to three metal plates, which are combined so that they are at 90 degrees to each other. The reflection characteristic value RCS of the corner reflector is generally calculated by the following equation when the side length L of the reflector and the wavelength λ of the radio wave (a constant value determined by the frequency of the on-vehicle radar device) are used. Therefore, if the side L of the reflector in FIG. 2 is 14 cm, it is possible to obtain a reflection characteristic value of about 14 dBsm at a frequency of 76 GHz and about 12 dBsm at a frequency of 60 GHz. In general passenger cars, it is known that it is about 12 dBsm (about 6 dBsm for a sedan type), but it can be said that it is sufficiently effective in view of these numerical values (for example, see Patent Document 2).

Further, even if the vehicle body 12 portion facing the reflector structure 13 is an uneven portion, the vehicle body 12 portion is made of a member having good radio wave transmission, such as ABS resin or acrylic resin. It is made so that a strong intensity distribution can be obtained.

Therefore, even if there are few reflective surfaces such as a general passenger car, radio waves emitted from the in-vehicle radar device are transmitted through the vehicle body 12 by making the uneven portion of the vehicle body 12 a member having good radio wave transmission. Then, the light is reflected by the reflector structure 13, and the reflected wave faces the direction of the incident wave. Accordingly, it is possible to suppress the reflection intensity distribution variation at the uneven portion at the center of the rear part of the vehicle and obtain a uniform intensity distribution.
As a result, radio waves emitted from the vehicle-mounted radar device of the rear vehicle to the casing unit 9 are reflected to the vehicle-mounted radar device, and the predetermined reflection intensity can be kept stable. Can do.

Embodiment 2. FIG.
FIG. 3 is a cross-sectional view showing a configuration of a rear emblem 2 according to Embodiment 2 of the present invention.
The rear emblem 2 provided at the center in the vehicle width direction of the rear part of the vehicle shown in FIG. 1 is composed of a reflector structure 14 and a plate 15 on its exterior as shown in FIG.
The plate 15 is usually designed with a manufacturer name or a car name, and is formed of a member that transmits radio waves well, such as ABS resin or acrylic resin.
The reflector structure 14 is, for example, a quadrilateral dihedral corner reflector 16 formed of metal as shown in FIG. 4 and having a side a having a length of several tens of wavelengths (3 mm to 6 mm). Alternatively, the triangular three-surface corner reflector 17 is formed of a metal as shown in FIG. 5 and has a length of one side b of several tens of wavelengths (3 mm to 6 mm).

When a single reflector is used, it is necessary to increase the reflector side length L in order to increase the reflection characteristics. However, as the reflector side length L increases, the thickness in the opening direction also increases. Therefore, instead of increasing the side length L with a single reflector, a plurality of reflector side lengths L (wavelength sizes) are arranged, and the reflection characteristics RCS of the reflectors arranged in plurality are improved in total.
That is, for example, the reflector portion 14 of FIG. 3 is a rectangular double-sided corner reflector (FIG. 4) formed of a metal having a side a having a length of about one wavelength (3 mm to 6 mm) as shown in FIG. ) Are arranged in a quadrilateral two-sided corner reflector array 18. Alternatively, as shown in FIG. 7, a triangular three-surface corner reflector array 19 in which one side has a length of about one wavelength (3 mm to 6 mm) and a plurality of triangular three-surface corner reflectors (FIG. 5) made of metal are arranged. By doing so, the thickness can be reduced and the same level of reflection characteristics can be obtained.

Embodiment 3 FIG.
8 and 9 are cross-sectional views showing configurations of the trunk handle 3 and the garnish portion 4 according to Embodiment 3 of the present invention, and are provided at the center in the vehicle width direction of the rear portion of the vehicle as shown in FIG.
8 and 9, a trunk handle 3 of the trunk room provided at the rear of the vehicle is a handle for opening and closing the door of the trunk, and 4 is a garnish provided to facilitate gripping of the handle. A reflector structure 20 is provided inside the garnish portion 4 as shown in FIGS.
In the reflector structure 20 of FIG. 8, the same rectangular two-sided corner reflector 16 as already described in FIG. 4 or a triangular three-sided corner reflector 17 as shown in FIG. 5 is used.
Alternatively, in the reflector structure 20 of FIG. 9, a square two-sided corner reflector array 18 as shown in FIG. 6 or a triangular three-sided corner reflector array 19 as shown in FIG. 7 is used.

Embodiment 4 FIG.
FIG. 10 is a sectional view showing the configuration of the license plate peripheral portion 5 according to the fourth embodiment of the present invention, and is provided at the center in the vehicle width direction of the rear portion of the vehicle as shown in FIG.
In FIG. 10, 21 is a reflector structure, and the reflector 21 and the number plate 22 are integrally formed. At this time, the member of the license plate 22 is a member that transmits radio waves well, such as ABS resin and acrylic resin.
As shown in FIG. 6, the reflector structure 21 has a rectangular double-sided corner in which a plurality of rectangular double-sided corner reflectors (FIG. 4) each having a side a length of about one wavelength (3 mm to 6 mm) and made of metal. A reflector array 18 is assumed. Alternatively, as shown in FIG. 7, a triangular trihedral corner reflector array 19 in which a plurality of triangular trihedral corner reflectors (FIG. 5) formed of metal having one side a having a length of about one wavelength (3 mm to 6 mm) is provided. Thus, the thickness can be reduced, and good reflection characteristics in the incident direction of the radio wave can be obtained.

Embodiment 5 FIG.
11 and 12 are cross-sectional views showing the configuration of the garnish portion 6 of the license plate peripheral portion 5 according to the fifth embodiment of the present invention. As shown in FIG. ing.
11 and 12, the license plate 22 is provided on the outer surface of the garnish portion 6 for decorating the periphery of the license plate, and a reflector structure 23 is provided inside the garnish portion 6. The license plate 22 and the garnish portion 6 are made of members such as ABS resin and acrylic resin that transmit radio waves well to the reflector structure 23.
In the reflector structure 23 of FIG. 11, the same rectangular two-sided corner reflector 16 as already described in FIG. 4 of the second embodiment or the triangular three-sided corner reflector 17 as shown in FIG. 5 is used. Alternatively, in the reflector structure 23 of FIG. 12, a square two-sided corner reflector array 18 as shown in FIG. 6 or a triangular three-sided corner reflector array 19 as shown in FIG. 7 is used.

Embodiment 6 FIG.
FIG. 13 is a partial cross-sectional view of the rear wiper arm 7 of the rear wiper device 1 according to the sixth embodiment of the present invention.
In FIG. 13, the rear wiper arm 7 of the rear wiper device 1 installed at the center in the vehicle width direction at the rear of the vehicle includes a protective cover 24 for the rear wiper arm 7 for improving the exterior and a reflector structure for reflecting radio waves. 25. It is comprised from the rubber element 26 which is a part which touches a glass surface.
The reflector structure 25 is a triangular three-surface corner reflector array 19 (FIG. 7) in which a plurality of triangular three-surface corner reflectors, each of which is formed of a metal having one side b having a length of about one wavelength (3 mm to 6 mm).
According to the rear wiper device 1, the in-vehicle radar device can obtain the reflection intensity of the radio wave with respect to the movement of the rear wiper arm 7 by the reflector structure 25 provided on the rear wiper arm 7.

Further, in the vehicle-mounted radar device for the rear vehicle, the following effects can be obtained by determining the rear wiper device in the sixth embodiment.
That is, when the rear wiper device 1 is driven, the rear wiper arm 7 of the rear wiper device 1 wipes once, while the scanning cycle of the in-vehicle radar device is several ms or less. The time is controlled with a period as long as several seconds. Accordingly, in the on-vehicle radar device mounted on the vehicle traveling behind, the reflector structure portion 25 provided on the rear wiper arm 7 is also moved by the wiping operation of the rear wiper device 1, so that the on-vehicle radar device is By continuously observing the reflection intensity distribution of the vehicle, it is possible to detect the change accompanying the periodic wipe control of the rear wiper device on the in-vehicle radar device side. Therefore, the in-vehicle radar device may be a rear wiper device. I understand.
Even when the rear wiper device 1 is not driven, the reflection strength is increased on the stationary side of the rear wiper arm 7 when combined with reflectors provided at both ends of the rear portion of the vehicle.
Further, if it can be determined whether or not it is a rear wiper device, it can be determined whether or not the vehicle has a rear wiper device at the rear of the vehicle traveling ahead, that is, whether or not there is a rear glass window at the rear of the vehicle.

The wiping operation method of the rear wiper device includes a parallel interlocking type in which two rear wiper arms swing in the same direction, an opposing type in which two rear wiper arms swing in opposite directions, and as shown in FIG. There are various single swing type commonly used in rear window glass, and the installation location varies depending on the vehicle type etc., but in the in-vehicle radar device, a constant reflection intensity is obtained at a location at the rear of the vehicle. Alternatively, the periodic fluctuation of the reflection intensity distribution is very effective as determination information for recognizing the vehicle such as pairing processing.
Further, the left and right center positions of both ends of the front vehicle can be detected from the detection data of the rear wiper device obtained by the on-vehicle radar device and the detection data obtained by providing the reflectors at both ends of the rear of the vehicle. The processing accuracy of pairing processing and vehicle width detection of the radar device can be improved.
The center part of the vehicle can be detected in this way, improving the accuracy of pairing processing, edge detection, and vehicle width detection for in-vehicle radar devices, LSF (Low Speed Following), and Full Speed Range ACC (FSRA, Full Speed Increases the reliability of vehicle detection in systems such as Range ACC.

The reflector structure 25 provided on the rear wiper arm 7 may be a quadrilateral two-sided corner reflector.
In the quadrilateral dihedral corner reflector, the direction of the incident wave must be within the plane formed by the normals of the two surfaces in order to match the directions of the incident wave and the reflected wave. It is also well known that the polarization angle of the reflected wave is changed by twice the rotation angle by rotating the opening surface around the direction of the incident wave.

Embodiment 7 FIG.
In the reflector structure 25 of the radar reflecting apparatus in the seventh embodiment, a quadrilateral two-surface corner reflector 16 as shown in FIG. 4 is used instead of the triangular three-surface corner reflector array 19 in the sixth embodiment in which a plurality of triangular three-surface corner reflectors are arranged. This is the case.
In the case of using this quadrangular double-sided corner reflector 16, the shape of the rear wiper arm 7 is inevitably increased when the reflector side length L is increased in order to increase the reflection characteristic value RCS. Although limited to the diameter of the wiper arm 7, in consideration of this point, a reflector made of metal having a length of 3 mm or more is provided.
When such a rectangular two-sided corner reflector 16 is provided on the rear wiper arm 7 as shown in FIG. 1, when the rear wiper device 1 is wiped and moved in the rain or the like, the rotation angle and the polarization angle of the rear wiper arm 7 Since the reflected intensity is maximized when the reflected waves are directed in the direction in which the radio waves are incident and the in-vehicle radar device continuously observes, the periodic control of the rear wiper arm 7 is possible. As a result, the peak fluctuation of the reflected intensity can be observed, and it can be seen that the apparatus is a rear wiper device.

Embodiment 8 FIG.
In the eighth embodiment of the present invention, a heater is provided inside the rear wiper arm 7. Thus, by providing a temperature-adjustable heater inside the rear wiper arm 7, snow can be melted during snowfall and ice can be melted during freezing, so that the function as a radar reflector can be maintained.

It is explanatory drawing which shows arrangement | positioning of the various members which show each embodiment of this invention. 1 is a perspective view schematically showing the structure of a rear wiper device that is Embodiment 1 of the present invention. FIG. It is a figure which shows schematically the structure of the rear emblem which is Embodiment 2 of this invention. It is a figure which shows the structure of a quadrilateral two-surface corner reflector by the radar reflecting device in this invention. It is a figure which shows the structure of a triangular trihedral corner reflector by the radar reflective apparatus in this invention. It is a figure which shows the structure of a quadrilateral two-plane corner reflector array by the radar reflecting device in this invention. It is a figure which shows the structure of a triangular three-plane corner reflector array by the radar reflector in this invention. It is a figure which shows schematically the structure of the trunk handle periphery which is Embodiment 3 of this invention. It is a figure which shows schematically the structure of the trunk handle periphery which is Embodiment 3 of this invention. It is a figure which shows schematically the structure around the license plate which is Embodiment 4 of this invention. It is a figure which shows schematically the structure around the license plate which is Embodiment 5 of this invention. It is a figure which shows schematically the structure around the license plate which is Embodiment 5 of this invention. It is a figure which shows roughly the structure of the rear wiper arm which is Embodiment 6 of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Rear wiper apparatus 2 Rear emblem 3 Trunk handle 4 Garnish part around trunk handle 5 Number plate part 6 Decoration garnish part around license plate 7 Rear wiper arm 8 Rear wiper pivot shaft 9 Casing part 10 Protective cover 11 Clamping fixture DESCRIPTION OF SYMBOLS 12 Car body 13 Reflector structure of casing part 14 Reflector structure of rear emblem 15 Rear emblem plate 16 Square two-sided corner reflector 17 Triangular three-sided corner reflector 18 Square two-sided corner reflector array 19 Triangular three-sided corner reflector array 20 Reflector around door handle Structure 21 Reflector structure around the license plate 22 Number plate 23 Reflector structure around the license plate 24 Rear Y Amu reflector structure 26 rubber element of the protective cover 25 rear wiper arm.

Claims (7)

In a radar reflector installed in a rear wiper device having a rear wiper arm for wiping the rear window glass and disposed at the center in the vehicle width direction at the rear of the vehicle, radio waves emitted from another rear vehicle to the rear wiper arm A transmissive member that transmits light and a reflector portion that is provided inside the transmissive member and reflects the transmitted radio wave toward the other rear vehicle, and the reflector portion is allowed to co- operate with the rear wiper arm. Radar reflector. 2. The radar reflecting apparatus according to claim 1, wherein a reflector portion that reflects the radio wave toward the rear vehicle is disposed on both sides in the vehicle width direction of the rear portion of the vehicle, separately from the reflector portion . 3. The radar reflector according to claim 1 , wherein the rear wiper arm is provided with a temperature-adjustable heater that melts and melts ice during snowfall and freezing . 2. The radar reflector according to claim 1, wherein the reflector is a triangular three-surface corner reflector made of metal . The radar reflector according to claim 1 , wherein the reflector is a quadrilateral two-sided corner reflector . 2. The radar reflector according to claim 1 , wherein the reflector includes a plurality of triangular trihedral corner reflectors each having a side of 3 mm to 6 mm . 2. The radar reflecting apparatus according to claim 1 , wherein the reflector unit includes a plurality of quadrilateral two-sided corner reflectors each having a side of 3 mm to 6 mm .

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