JP2542065B2 - Vehicle inter-vehicle distance detection device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention relates to a vehicle (vehicle) which detects an inter-vehicle distance between the vehicle and another vehicle (leading vehicle or trailing vehicle). The present invention relates to an inter-vehicle distance detecting device.

(Prior Art) Conventionally, as described in, for example, JP-A-62-54189, signals such as radio waves, laser light, and ultrasonic waves are transmitted forward from a vehicle, and the signals are transmitted from the vehicle. An inter-vehicle that receives a reflected signal reflected back from a preceding vehicle located in front of the vehicle and calculates the inter-vehicle distance between the own vehicle and the preceding vehicle based on a signal round-trip time (delay time) from transmission to reception. A distance detecting device is known.

(Problems to be Solved by the Invention) However, in the inter-vehicle distance detecting device as described above, for example, when the inter-vehicle distance to a preceding vehicle is detected, the visual field (detection range) direction of the detecting device is usually the own vehicle. Since it is set toward the front of the car, there is no problem when driving straight, but when traveling in a curve, the preceding vehicle moves to the right if it is a right curve, to the left if it is a left curve, There is a problem of malfunction in that an object other than the preceding vehicle such as the guardrail is located, and as a result, the inter-vehicle distance is detected by the reflected signal from the object other than the preceding vehicle such as the guardrail.

Such a problem also exists in the case where a signal is transmitted backward from the own vehicle to detect the inter-vehicle distance to the following vehicle located behind the own vehicle.

In view of the above situation, the object of the present invention is to provide a measurement target even when another vehicle moves in the left-right direction with respect to the own vehicle.
The movement, for example, the movement direction or the movement amount is detected, the visual field direction of the inter-vehicle distance detecting means is changed based on the movement, and the other vehicle is tracked, and thus the inter-vehicle distance between the own vehicle and the other vehicle is accurately detected. An object of the present invention is to provide a vehicle-to-vehicle distance detecting device.

(Means for Solving the Problem) In order to achieve the above object, the vehicle-to-vehicle distance detecting means according to the present invention transmits a signal, receives a reflected signal of the transmitted signal, and based on the reflected signal. Distance detection means for detecting the distance between the own vehicle and another vehicle, a light spot position detection means for detecting the position of the light spot, and light emitted from the other vehicle on the light spot position detection means. And a control means for controlling the visual field direction of the inter-vehicle distance detection means based on the light spot position information output from the light spot position detection means.

As the signal, radio waves such as microwaves, light such as laser light, or sound waves such as ultrasonic waves can be used.

The light emitted from the other vehicle may be, for example, reflected light in which the transmitted light is reflected back to another vehicle when the signal for detecting the inter-vehicle distance is light, or When the other vehicle is a preceding vehicle, it may be infrared rays emitted from a high temperature portion of the exhaust pipe portion at the rear of the preceding vehicle.

(Operation) If the light emitted from the other vehicle is converged on the light spot position detecting means by a converging means such as a condensing lens, when the other vehicle moves left and right with respect to the own vehicle, etc. The convergence position (spot position) of the light emitted from the vehicle on the light spot position detecting means changes in accordance with the movement of the other vehicle. Therefore, with the above configuration, the movement of the other vehicle can be detected by the position information of the light spot on the light spot position detecting means, and the inter-vehicle distance detecting means can be detected based on the spot information (moving information of the other vehicle). By changing the visual field direction of the vehicle, it is possible to always direct the visual field of the inter-vehicle distance detecting device to the other vehicle to be measured, and as a result, even if the other vehicle moves with respect to the own vehicle while traveling on a curve, etc. It is possible to always accurately detect the inter-vehicle distance from other vehicles without causing malfunction due to unnecessary reflection signals from other vehicles.

(Examples) Hereinafter, examples of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a block diagram showing an embodiment of an inter-vehicle distance detecting device for a vehicle according to the present invention. In this embodiment, the other vehicle to be measured is a preceding vehicle, and infrared rays emitted from the exhaust pipe of the preceding vehicle are detected as the light emitted from the preceding vehicle for detecting the movement of the preceding vehicle. .

In this embodiment, as shown in the drawing, the following distance detection means 2, a light spot position detection means 4, a convergence means 6, and a control means 8 are provided.
And.

The inter-vehicle distance detecting means 2 transmits a signal, receives the reflected signal which is returned by reflecting the transmitted signal to another vehicle as a measurement target, for example, a preceding vehicle, and based on the received reflected signal, the own vehicle. And a vehicle-to-vehicle distance between the other vehicle and the vehicle-to-vehicle distance is detected.For example, as a method of detecting the vehicle-to-vehicle distance, a pulse signal is transmitted, and a period from transmission of the pulse signal to reception of a reflected signal of the pulse signal is detected. It may be a pulse modulation method that measures the signal round-trip time (delay time) and detects the distance based on it, AM modulation, FM modulation, or even triangulation, for example. good.

FIG. 2 is a block diagram showing an example of the vehicle-to-vehicle distance detecting means 2. The driving circuit 10 drives the semiconductor laser 12 to cause the semiconductor laser 12 to emit a pulsed laser beam, and the laser beam is transmitted by a transmission lens. At the same time as transmitting through 14, the transmitted laser light is reflected by another vehicle and returned and collected by the receiving lens 16, photoelectrically converted by the photodiode 18, and the electric signal is calculated by the calculating means 22. The calculation means 22 calculates the delay time from the time of transmission to the time of reception based on the input of the received signal and the signal transmission information input from the drive circuit 10, and detects the inter-vehicle distance based on it. Is configured.

Returning to FIG. 1, the movement of the preceding vehicle 24 is detected by the light spot position detecting means 4 and the converging means 6 based on the infrared rays 26 emitted from the exhaust pipe 24a portion of the preceding vehicle 24. The converging means 6 is composed of a condensing lens, condenses the infrared light and converges it on the light spot position detecting means 4 to form a light spot on the detecting means 4. The light spot position detecting means 4 comprises a light detecting section 28 on which infrared rays are converged and incident by a condenser lens 6 and a calculating section 30 for obtaining a moving direction and a moving amount of a preceding vehicle based on an output from the light detecting section 28. As the photodetection unit 28, a split photodetection unit is used in which photodetectors 28a and 28b are arranged on both sides of the optical axis of the condenser lens 30, respectively.

The exhaust pipe 24a becomes hot and infrared rays 2
6 is radiated, and the infrared ray 26 is converged by the condenser lens 6 on the photodetection section 28 of the light spot position detection means.
A light spot is formed on the light detecting portion 28.

Now, when the preceding vehicle 24 is at the left side position shown by the broken line in FIG. 1, the infrared rays 26 radiated from the exhaust pipe 24a also converge on the right side photodetector 28a through the optical path shown by the broken line, and thus the light is emitted. The spot is located on the right side photodetector 28a. From this state, when the preceding vehicle 24 moves to the right and is located at the right position shown by the solid line in FIG. 1, the infrared rays 26 emitted from the exhaust pipe 24a also pass through the optical path shown by the solid line and on the left photodetector 28b. , So that the light spot is located on the left photodetector 28b. That is, the spot position of the infrared rays 26 on the light detecting portion 28 moves to the left side when the preceding vehicle moves to the right side. Of course, when the preceding vehicle moves to the left, the light spot position moves to the right. Third
The drawing is a view taken along the line III-III in FIG.
7 illustrates movement of the position of the light spot 32 in the figure.

If the moving direction and the moving amount of the position of the light spot 32 are obtained, then the moving direction and the moving amount of the preceding vehicle 24 can be obtained. The moving direction and the moving amount of the light spot 32 are output from the two photodetectors 28a and 28b (each photodetector 2).
The light quantities S ₁ and S ₂ received by 8a and 28b are calculated by the calculation unit 30, for example, S ₁ −S ₂ or S ₁ / S ₂ .

When the moving direction and the moving amount of the preceding vehicle 24 are detected as described above, the detection information is input to the control means 8, and the control means 8 responds to the detection information by the visual field (detection range of the inter-vehicle distance detection means 2). ) Control the direction of 34. That is, the visual field direction of the inter-vehicle distance detecting means 2 is changed in the same direction as the above-mentioned detected moving direction so as to follow the moving preceding vehicle and to be directed toward the preceding vehicle, and by an amount corresponding to the detected moving amount. Let

By doing so, the reflected signal is always only the signal reflected from the preceding vehicle, and erroneous operation of the inter-vehicle distance detecting means 2 due to an unnecessary reflected signal reflected from something other than the preceding vehicle such as a guardrail is avoided even in a vehicle traveling on a curve. be able to.

When changing the visual field direction of the inter-vehicle distance detecting means 2, it suffices to change the signal transmission direction.
In the inter-vehicle distance detecting means 2 shown in FIG. 2, for example, the optical axis of the transmitting lens 14 may be the lens 14 alone or the lens 14
It is possible to change the emission direction of the laser light by moving and changing the semiconductor laser 12 and the semiconductor laser 12 integrally. Note that the receiving direction may be changed together with the transmitting direction.

FIG. 4 is a diagram showing another embodiment. In the embodiment shown in FIG. 1, the inter-vehicle distance detecting means 2 and the converging means 6 for detecting the movement of the preceding vehicle are provided separately, but in the embodiment shown in FIG. 4, the converging means 6 and the inter-vehicle distance are provided. It also serves as the receiving lens 16 (see FIG. 2) of the distance detecting means. That is, the signal used in the inter-vehicle distance detecting means 2 is light,
For example, in the case of laser light, the receiving lens 16 is used in the detecting means 2 as described above, and the laser light has a shorter wavelength than infrared light. When the same condenser lens is used, the laser light is shorter than infrared light. The focal length becomes shorter. Therefore, as shown in FIG. 4, the receiving lens 16 for the laser light 34 and the infrared rays
One lens is also used as the condenser lens 6 for 26, and the light detecting portion 28 of the light spot position detecting means is positioned exactly on the focus position of the laser light. If you position the photodiode 18 for
As shown in the figure, the infrared rays 26 form a spot on the photodetection unit 28, and the laser light is received by the photodiode 18 through the space between the photodetection bodies 28a and 28b. Can be achieved.

FIG. 5 is a block diagram showing still another embodiment.
In the embodiment shown in FIG. 1, the movement of the preceding vehicle is detected based on the infrared rays emitted from the exhaust pipe of the preceding vehicle, but in the embodiment shown in FIG. It is laser light, and the reflected light of the laser light from the preceding vehicle is used as the light emitted from the preceding vehicle for checking the movement of the preceding vehicle. Then, as shown in FIG. 5, not only the receiving lens 16 of the vehicle distance detecting means and the condensing lens 6 as the converging means can be used, but also the light detecting portion 28 of the light spot position detecting means is used as the vehicle distance detecting means. Can also be used as the receiving photodiode 18, and the device can be further downsized and the cost can be reduced.

The light spot position detecting means in each of the above-mentioned embodiments is of a split type using two separated photodetectors, but of course the present invention is not limited to this split type and one known photodetector is used. It is also possible to use a body type light spot position detecting means.

(Effects of the Invention) As described above, the vehicle-to-vehicle distance detecting device according to the present invention detects the movement of the other vehicle by the light emitted from the other vehicle to be measured, and based on that, the visual field of the vehicle-to-vehicle distance detecting means. The direction is changed so that the visual field direction is always directed toward the other vehicle. Therefore, even when the other vehicle moves with respect to the own vehicle, for example, when the vehicle travels in a curve, other than the other vehicle. It is possible to avoid the generation of unnecessary reflected signal from the, thereby preventing malfunction due to the unnecessary reflected signal,
The inter-vehicle distance between the other vehicle and the own vehicle can always be detected accurately.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of the device according to the present invention, FIG. 2 is a block diagram showing an example of inter-vehicle distance detecting means in FIG. 1, and FIG. 3 is III-III in FIG. 4 and 5 are block diagrams showing another embodiment of the device according to the present invention. 2 ... Inter-vehicle distance detecting means 4 ... Light spot position detecting means 6 ... Converging means, 8 ... Control means

 ─────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-62-145178 (JP, A) JP-A-62-36581 (JP, A) JP-A-61-259186 (JP, A) JP-A-60- 256076 (JP, A)

Claims (1)

(57) [Claims] 1. An inter-vehicle distance detecting means for transmitting a signal, receiving a reflected signal of the transmitted signal, and detecting a distance between the own vehicle and another vehicle based on the reflected signal, and an inter-vehicle distance detecting means. Based on the light spot position detecting means for detecting the position, the converging means for converging the light emitted from the other vehicle on the light spot position detecting means, and the light spot position information output from the light spot position detecting means. And a control means for controlling the visual field direction of the inter-vehicle distance detecting means.