JPH1097698A - Vehicle-to-vehicle distance measuring instrument - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the reliability of a vehicle-to-vehicle distance measuring instrument by preventing the instrument from measuring the distance to an object other than another object to be measured even on a curved road. SOLUTION: A light emitting device 19 provided in the rear section of a preceding vehicle 1 emits a light wave toward a succeeding vehicle 2 as a projected light beam 20. A range finder 3A attached to the front section of the succeeding vehicle 2 is composed of a tracking section 22, a beam directing section 23, and a range finding section 24. The tracking section 22 receives the beam 20 emitted from the light emitting device 19 of the preceding vehicle 1, measures the direction of incidence of the beam 20, and outputs an obtained angle signal 25 to the beam directing section 23. The section 23 emits a range finding beam 5 toward the light emitting device 19 of the preceding vehicle 1 after directing the beam 5 toward the device 19 based on the angle signal 25 and receives the reflected beam of the beam 5 from the preceding vehicle 1. The section 23 outputs the received optical signal to the range finding section 24 and the section 24 obtains the vehicle-to-vehicle distance data 7 between the two vehicles 1 and 2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tracking type inter-vehicle distance measuring apparatus using light waves used for inter-vehicle distance control of a vehicle running in a group.

[0002]

2. Description of the Related Art As conventional inter-vehicle distance measuring devices using light waves, there are mainly a device using a beam switching system and a device using a beam scanning system. Hereinafter, the inter-vehicle distance measuring devices according to the respective methods will be briefly described.

FIGS. 3 and 4 are views showing an inter-vehicle distance measuring apparatus using a beam switching method, FIG. 3 is an overall configuration diagram thereof, and FIG. 4 is a diagram showing a detection range when three distance measuring beams are provided. is there. As shown in FIG. 3, when the rear vehicle 2 measures the inter-vehicle distance from the front vehicle 1, the distance switching unit 4 in the distance measuring device 3 </ b> B attached to the rear vehicle 2 transmits the beam switching unit 4.
The distance measuring beam 5 is projected forward through the optical system 1 and receives reflected light from the vehicle 1 ahead. Then, the distance measuring unit 6 measures the distance to the preceding vehicle 1 based on the respective information of the projection light and the reflected light to obtain the inter-vehicle distance data 7.

In the distance measuring operation, the beam switching unit 4
Switches the ranging beam 5 by a switching signal 8 based on information such as the shape of the traveling path. For example, FIG. 4 shows the detection range of the distance measuring beam 5, and FIG. 4 shows a case where three distance measuring beams 5a, 5b, and 5c are provided. As shown in the figure, the beam switching unit 4 includes a ranging beam 5a,
One of 5b and 5c is selected, and the inter-vehicle distance is measured by the selected ranging beam.

FIGS. 5 and 6 are views showing an inter-vehicle distance measuring apparatus using a beam scanning method. FIG. 5 is a diagram showing the overall configuration thereof, and FIG. 6 is a view showing a detection range of a ranging beam. As shown in FIG. 5, a distance measuring beam 5 is emitted from a distance measuring unit 9 in a distance measuring device 3C of the rear vehicle 2. This ranging beam 5
Is scanned by the beam scanning unit 10 and is irradiated on an object in the search range. Here, FIG. 6 shows the ranging beam 5 and a search range 11 of the ranging beam 5.

Next, the ranging beam 5 scanned by the beam scanning unit 10 is reflected by the vehicle 1 ahead, and the reflected beam is received by the beam scanning unit 10. The received optical signal is output to the distance measuring unit 9. The distance measuring unit 9 obtains distance data 12 to the preceding vehicle 1 based on the received light signal and the generated distance measuring beam 5, that is, information on the projected light and the reflected light. The distance data 12 is output to the determination unit 13.

On the other hand, the vehicle presence range detecting means 14 provided in the distance measuring device 3C detects the presence range of the preceding vehicle 1 by performing, for example, image processing of a white line written on the traveling path, and detects the vehicle presence range information. 15 is output to the determination unit 13. The determination unit 13 determines the distance data 12 and the vehicle presence range information 1
Then, an inter-vehicle distance is calculated on the basis of No. 5 and inter-vehicle distance data 7 is obtained.

[0008]

The above-mentioned conventional inter-vehicle distance measuring apparatus has the following problems. That is, in the case of the beam switching method, the traveling path 16 is curved as shown in FIG. 7, and when the inter-vehicle distance between the rear vehicle 2 and the front vehicle 1 traveling in the same direction is measured, the distance measuring beam 5 is used. By switching by the switching unit 4, the detection range is also switched to each of the ranges 17a, 17b, and 17c. In the case of the figure, switching is performed so that the detection range becomes 17a from the traveling position of the preceding vehicle 1. At this time, the ranging beam 5 is emitted to the object in the detection range 17a. However, since an obstacle on the side of the traveling path enters the detection range 17a of the ranging beam 5, the front vehicle 1 and the obstacle can be distinguished. Can not do. That is, the distance to the obstacle may be measured, and the reliability of the measured distance information is low.

FIG. 8 shows a distance measuring operation in the case of the beam scanning method. As described above, the vehicle existence range detecting means 14 such as image processing of a white line written on the traveling path 16 is used to detect the existence range of the vehicle. If it cannot be obtained, the correct vehicle presence range cannot be obtained. Here, the search range 11
When the ranging beam 5 is emitted within the area, if a reliable image is used, the detection range of the ranging beam 5 is 18a.
The correct inter-vehicle distance can be calculated, but if the image is of poor quality, the detection range may be 18b. In this case, the distance to the obstacle on the side of the traveling road may be output as the inter-vehicle distance, Low reliability.

As described above, in both the beam switching system and the beam scanning system, when a vehicle is tracked, the distance between vehicles in front of and behind the road cannot be accurately and safely determined, so that a collision may occur.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to measure the distance between vehicles even on a curved road without measuring the distance to an object other than the vehicle to be measured. An object of the present invention is to provide a highly reliable inter-vehicle distance measuring device that can measure accurately.

[0012]

According to the present invention, there is provided an inter-vehicle distance measuring apparatus for transmitting a ranging beam from a first vehicle to measure an inter-vehicle distance to a second vehicle.
A light-emitting device attached to the second vehicle and emitting a light wave as a beam toward the first vehicle; a tracking device attached to the first vehicle and measuring a direction in which the light wave from the light-emitting device is incident; A light wave type distance measuring device attached to the first vehicle and directing a narrow distance measuring beam in the direction of the light emitting device based on a measurement result of the tracking device to measure an inter-vehicle distance to the second vehicle; It is characterized by having.

According to the inter-vehicle distance measuring apparatus of the present invention, the following operations and effects are obtained. A light wave is emitted from the light emitting device of the second vehicle as a beam toward the first vehicle. On the other hand, in the first vehicle, the tracking device receives the light wave from the light emitting device and measures the incident direction of the light wave. The measurement result obtained by this tracking device is output to the lightwave type distance measuring device as an angle signal. The light wave type distance measuring device transmits a narrow distance measuring beam in the direction of the light emitting device based on the obtained measurement result to measure the inter-vehicle distance to the second vehicle.

As described above, the tracking device tracks the incident direction of the light wave transmitted from the second vehicle, that is, the light-emitting device of the second vehicle, and emits the ranging beam, thereby more accurately measuring the inter-vehicle distance. Can be performed, and the beam width of the distance measuring beam can be reduced. For this reason, since the measurement target is reliably captured without measuring the distance to an object other than the measurement target vehicle, a highly reliable inter-vehicle distance measurement can be performed.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is an overall configuration diagram showing an inter-vehicle distance measuring apparatus according to an embodiment of the present invention, and shows, as an example, a case where a rear vehicle 2 measures an inter-vehicle distance to a front vehicle 1. In FIG. 1, a light-emitting device 19 is attached to a rear portion of a vehicle 1 in front. The light emitting device 19 emits light toward the rear vehicle 2 using a light wave as a beam (hereinafter, a light beam is referred to as a light projecting beam 20).
).

In order to distinguish the light beam 20 from other natural light or disturbance light, infrared light is used, or the light beam 20 is modulated at an appropriate frequency and filtered at the light receiving side. Only the emitted light, that is, the light projection beam 20 may be extracted.

A distance measuring device 3A is attached to the front portion of the rear vehicle 2. The distance measuring device 3A includes a tracking unit 22, a beam directing unit 23, and a distance measuring unit 24. The tracking unit 22 measures the incident direction of the light projecting beam 20 emitted from the light emitting device 19 of the preceding vehicle 1, and obtains the obtained angle signal 2.
5 is output to the beam directing unit 23. This beam directing part 2
Reference numeral 3 denotes a direction in which the distance measuring beam 5 having a narrow beam width is incident on the projection beam 20 based on the angle signal 25, that is, the forward vehicle 1
In the direction of the light emitting device 19. The beam directing unit 23 receives a light wave reflected on the vehicle 1 ahead. The received optical signal is output to the distance measuring unit 24. The distance measuring unit 24 obtains the inter-vehicle distance data 7 based on the information of each of the incident light and the reflected light.

The operation of the above embodiment will be described with reference to FIGS. As shown in FIG. 1, the front vehicle 1 informs the rear vehicle 2 of the traveling position, so that
Is emitted from the light emitting device 19.

On the other hand, in the rear vehicle 2, the distance measuring device 3A
The tracking unit 22 in the inside points the light receiving beam 21 to receive the light projecting beam 20. The tracking unit 22 measures the incident direction of the light beam 20 by receiving the light beam 20 and outputs an angle signal 25 indicating the incident direction of the light beam 20.
Get. The angle signal 25 is output to the beam directing unit 23.

Next, the beam directing unit 23 outputs the angle signal 2
The direction in which the distance measuring beam 5 is emitted based on the
It is directed in the direction of incidence of 0. Here, the ranging beam 5 generated by the ranging unit 24 is emitted toward the direction determined by the beam directing unit 23, that is, toward the light emitting device 19 of the vehicle 1 ahead.

The emitted distance measuring beam 5 is directed by the beam directing section 23 in the direction of the light emitting device 19 of the preceding vehicle 1, hits the preceding vehicle 1 and is reflected. Beam directing unit 23
Receives the reflected light wave, and outputs the received light signal to the distance measuring unit 24.

Next, the distance measuring unit 24 determines the distance to the rear vehicle 2 based on the information of the optical signal obtained by reflection from the preceding vehicle 1 and the distance measuring beam 5, that is, the information of the incident light and the reflected light. Calculates and outputs the inter-vehicle distance data 7 from the vehicle to the preceding vehicle 1.

FIG. 2 shows the measurement of the inter-vehicle distance on the actual curved road in the above operation. FIG.
In, the front vehicle 1 and the rear vehicle 2 are traveling on the curved traveling path 16 in the same direction. Here, since the light emitting beam 20 emitted from the light emitting device 19 of the front vehicle 1 has a wide beam width, the distance measuring device 3A of the rear vehicle 2
Incident on. Since the distance measuring device 3A directs the distance measuring beam 5 in the incident direction of the light projecting beam 20 from the front vehicle 1 as described above, the distance measuring device 3A accurately hits the front vehicle 1 even with a narrow beam width. In addition, since the beam width is so narrow, the distance to the vehicle 1 ahead can be reliably measured without measuring an obstacle on the side of the traveling road.

In the above-described embodiment, the case where the front vehicle 1 emits the light projecting beam 20 and the distance measuring device 3A of the rear vehicle 2 tracks the light projecting beam 20 and emits the distance measuring beam 5 has been described. Of course, the light emitting device may be attached to the rear vehicle and the distance measuring device may be attached to the front vehicle, and the front vehicle may similarly measure the inter-vehicle distance with the rear vehicle.

[0025]

As described above, according to the present invention, the tracking device tracks the incident direction of the light wave transmitted from the vehicle to be measured, and emits the distance measuring beam in the incident direction. The distance between vehicles can be measured, and the range of the ranging beam can be reduced. Therefore, highly reliable inter-vehicle distance measurement can be performed without measuring the distance to an object other than the measurement target vehicle.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of an inter-vehicle distance measuring device according to an embodiment of the present invention.

FIG. 2 is a view showing the operation of the following distance measuring apparatus in the embodiment.

FIG. 3 is a diagram showing a configuration of a conventional inter-vehicle distance measuring apparatus using a beam switching method.

FIG. 4 is a diagram showing a detection range of a ranging beam in a conventional inter-vehicle distance measuring apparatus using a beam switching method.

FIG. 5 is a diagram showing a configuration of a conventional inter-vehicle distance measuring apparatus using a beam scanning method.

FIG. 6 is a diagram showing a detection range of a ranging beam in a conventional inter-vehicle distance measuring apparatus using a beam scanning method.

FIG. 7 is a diagram showing a distance measuring operation of a conventional inter-vehicle distance measuring apparatus using a beam switching method.

FIG. 8 is a diagram showing a distance measuring operation of a conventional inter-vehicle distance measuring apparatus using a beam scanning method.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 front vehicle 2 rear vehicle 3A distance measuring device 5 distance measuring beam 7 inter-vehicle distance data 16 travel path 19 light emitting device 20 light emitting beam 21 light receiving beam 22 tracking unit 23 beam directing unit 24 distance measuring unit 25 angle signal

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Hiroyuki Mochi 5007 Itozakicho, Mihara City, Hiroshima Prefecture Mitsubishi Heavy Industries, Ltd.Mihara Works Co., Ltd. Inside the factory

Claims (1)

[Claims] 1. An inter-vehicle distance measuring device for transmitting a ranging beam from a first vehicle to measure an inter-vehicle distance to a second vehicle, wherein the inter-vehicle distance measuring device is attached to the second vehicle and directed to the first vehicle. A light emitting device that emits a light wave as a beam, a tracking device attached to the first vehicle, and a tracking device that measures a direction in which the light wave from the light emitting device is incident; and a tracking device attached to the first vehicle, An inter-vehicle distance measuring device, comprising: a light-wave type distance measuring device that directs a narrow distance measuring beam in the direction of the light emitting device based on the measurement result to measure an inter-vehicle distance with the second vehicle.