JPH05273351A - Device for detecting position of preceding vehicle - Google Patents

Abstract

PURPOSE:To eliminate the influence of vibrations so as to easily and inexpensively detect the position of a preceding vehicle by simultaneously transmitting pulsed laser beams from at least three transmitting means installed to the front section of a vehicle so that the laser beams can be reflected by means a reflecting plate installed to the rear section of the preceding vehicle. CONSTITUTION:At least three transmitting means 2a-2c are installed to the front section of a vehicle 100 and made to simultaneously transmits pulsed laser beams from a signal source 1. As a result, some of the pulsed lasers are reflected by a reflecting plate 200 installed to the rear section of a preceding vehicle 101. When, for example, the preceding vehicle 101 is on the front left side, the detecting beam 4c from the left-side means 2c is reflected by the plate 200. The reflected beam 5c is received by means of a receiving means 7c and the corresponding preceding vehicle position displaying means 10c is actuated and informs the driver that the preceding vehicle 101 is on the front left side. In addition, a time difference detecting means 8c detects the time difference from the transmission to the reception and a distance- between-two-vehicles calculating means 9 calculates the distance between the preceding vehicle and its own vehicle from the time difference and speed of the beam 4c, for example, the speed of light and a distance-between-two-vehicles displaying means 11 displays the calculated distance.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a front vehicle position detecting device, and more particularly to a device for detecting a relative left and right position of a front vehicle (hereinafter referred to as a front vehicle) with respect to an own vehicle.

[0002]

2. Description of the Related Art Conventionally, as a device for detecting the left and right positions of a front vehicle relative to a vehicle, there is one disclosed in Japanese Patent Laid-Open No. 58-24876, in which the following three configurations are provided. Proposed.

(1) First, a vehicle having a pair of a front vehicle detection light transmitter using a light emitting diode installed at the focal point of a parabolic mirror and a light receiver for receiving the detection light reflected by the front vehicle is paired with a vehicle. A device provided in the front part to mechanically oscillate the transmitter / receiver within a predetermined angle to scan the front of the own vehicle and detect the left / right position of the front vehicle relative to the own vehicle.

(2) In the vicinity of the focal point of the parabolic mirror of the light transmitter, a plurality of light emitting diodes are installed on a line orthogonal to the light transmitting axis, and in the light receiver, a plurality of light receiving elements are similarly provided behind the light receiving lens. Install it on the line orthogonal to
By sequentially operating these light emitting diodes and light receiving elements in time series, even when the light transmitter / receiver itself is fixed, the front side of the vehicle is scanned in the same manner as the mechanical movement of the light transmitter / receiver as described above. A detection device configured to be able to.

(3) The directivity of the two sets of transmitters / receivers is made into a fan shape so that the respective detection lights are overlapped, the light receiving states of the respective receivers are divided, and the threshold value of the reflected light intensity corresponding to each division is set. A detection device that is set and obtains the same effect as scanning the front of the vehicle by comparing the reflected light intensity actually received with this threshold value.

[0006]

However, in the structure of the device disclosed in Japanese Patent Laid-Open No. 58-24876, the device (1) has a movable part for swinging motion.
Since this movable part is weak against vibration, its operation is affected by the vibration, and in the case of the device (2), a device in which a plurality of light emitting diodes are installed on a line near the focal point of the parabolic mirror is used as a light transmitter. In an apparatus that uses a plurality of light receiving elements arranged in a line behind a light receiving lens as a light receiver, none of the light transmitters and receivers is commercially available and becomes expensive.
Further, in the case of the device (3), there is a problem that its configuration becomes complicated.

Therefore, an object of the present invention is to provide an inexpensive front vehicle position detecting device which is not affected by vibration and has a simple structure.

[0008]

In order to achieve the above object, a front vehicle position detecting device according to the present invention is provided in one signal source 1 and a front portion of a vehicle 100, as shown in FIG. When energized by the signal source 1, each emits a pulse laser at the same time so that any one of the pulse lasers is reflected by at least one reflector 200 provided at the rear of the front vehicle 101. At least three transmitting means 2a to 2c in which the beam angle of the pulse laser is set, and receiving means provided corresponding to each transmitting means 2a to 2c so as to receive the pulse laser reflected by the reflecting plate 200. 7
a to 7c and front vehicle position display means 10a to 10c provided corresponding to the respective receiving means 7a to 7c.

Further, in the present invention, further, time difference detecting means 8a to 8c for calculating a time difference from the time when the signal source 1 is energized to the time when an output signal is generated from any of the receiving means 7a to 7c, and It is possible to include means 9 for calculating the inter-vehicle distance based on the time difference, and means 11 for receiving the output signal from the calculating means 9 and displaying the inter-vehicle distance.

[0010]

In the front vehicle position detecting device according to the present invention shown in FIG. 1, an example in which three transmitting means and three receiving means are provided is shown, and the center, right side and left side of the front part of the own vehicle 100 are shown. 3 sets of transmitting means 2a-2c and receiving means 7a-7
c and are provided. When the reference signal from one signal source 1 is received, the transmitting means 2a to 2c cause the front vehicle 10 to output the detection beams 4a to 4c whose pulse lasers have a constant beam angle.
Send to 1 at the same time. The detection beams 4a to 4c of the pulse lasers are arranged so that at least one reflection plate 200 provided at the rear of the front vehicle 101 reflects any one of the pulse lasers so that the beam angle of each pulse laser ( In the illustrated example, 2.7 °) is set.

At this time, for example, when the front vehicle 101 is on the left front of the own vehicle 100 as shown in the figure, the detection beam 4c from the transmitting means 2c installed on the left side of the own vehicle 100 is reflected by the front vehicle 101. It is reflected by the plate 200. That is, it is well known that the reflector 200, which is usually provided at the rear of the vehicle together with the tail lamp or the brake lamp, reflects the beam of the pulse laser beam along the same path. Therefore, the reflected beam 5c is received by the receiving means 7c. As a result, the front vehicle position display means 10c provided corresponding to the receiving means 7c is activated, and the front vehicle 101
It is possible to inform the driver that the left and right positions of the are on the left front side of the vehicle 100.

Further, in the present invention, the time difference ΔT (see FIG. 2) from the transmission of the detection beam 4c to the reception of the reflected beam 5c is detected by the time difference detecting means 8c, and the inter-vehicle distance calculating means 9 further detects the time difference detecting means 8c. Output and the speed of the detection beam 4c stored in advance (for example, the speed of light v = 3
It is also possible to calculate the inter-vehicle distance (inter-vehicle distance ΔL = ΔT × v) between the own vehicle 100 and the front vehicle 101 from (× 10 ⁸ m / s) and display it on the inter-vehicle distance display means 11.

Further, in the above description, it is assumed that the front vehicle 101 is on the left front side of the own vehicle 100, and the reflector 200 of the front vehicle 101
However, when a plurality of reflectors (for example, both sides of the front vehicle as usual) are provided, the front vehicle position display means 10a ...
10c, or front vehicle position display means 10a and 1
0b, or 10a and 10c actuate front vehicle 1
It goes without saying that it is possible to display whether 01 is in front of the front of the vehicle 100, on the left side or on the right side, or on the left side or on the right side.

[0014]

FIG. 3 shows the configuration of an embodiment of a front vehicle position detecting device according to the present invention. In this embodiment, the transmitting means 2a-2c for detecting beams 4a-4c shown in FIG. A commercially available laser light transmitter is used. And 3a to 3c are transmitting lenses which also constitute transmitting means 2a to 2c and give a beam angle θ to the detection beams 4a to 4c. Further, 5a to 5c are detection beams 4a to 4
c is a reflected beam reflected by the reflection plate 200 (see FIG. 1) of the front vehicle 101, and 6a to 6c are receiving lenses for condensing the reflected beams 5a to 5c, which constitute a receiving means. Reflected beams 5a to 5 condensed by the receiving lenses 6a to 6c
A commercially available laser light receiver can be used for the receivers 7a to 7c as the receiving means for receiving the signal c.

Further, 8a to 8c are time differences ΔTa and ΔT between the transmission of the detection beams 4a to 4c and the reception of the reflected beams 5a to 5c from the outputs of the transmitters 2a to 2c and the receivers 7a to 7c.
b and ΔTc (see FIG. 2), a time difference detecting unit as a time difference detecting unit, and 9 is time difference detecting units 8a, 8b, 8
Based on the output of c and the speed of the detection beam stored in advance, the vehicle 1
It is an inter-vehicle distance calculating unit as an inter-vehicle distance calculating means for calculating an inter-vehicle distance between 00 and the front vehicle 101.

Further, 10 is a front vehicle position display means, and a display section 10 corresponding to each of the time difference detection sections 8a to 8c.
This is a front vehicle position display section including a to 10c, and in this embodiment, it is not provided at the front stage of the detection sections 8a to 8c as shown in FIG. An inter-vehicle distance display unit 11 displays the inter-vehicle distance between the own vehicle 100 and the front vehicle 101 in response to a signal from the inter-vehicle distance calculation unit 9. Here, all of these display units are commercially available, and the front vehicle position display unit 10 is a single LED (light emitting diode),
Further, the inter-vehicle distance display unit 11 may use a 7-segment type LED.

In such an embodiment, the detection beam 4
As shown in FIG. 1, a to 4c are set so as to spread as they go forward by using the transmitting lenses 3a to 3c. As shown in FIG. 1, this is because the inter-vehicle distance on an ordinary road and the interruption distance on an expressway are usually around 50 m, so that it is possible to detect the full running lane width at this distance and to detect more than this. When the beams 4a to 4c are expanded, the beams are too widened to overlap each other and the respective reflected beams 5a to 5c are received by the unsupported beam receivers 7a to 7c (for example, the reflected beam 5a is received by the beam receiver 7b. It is set in this way because it is considered that opportunities will increase.

However, when the front vehicle 101 is located at a position exceeding the inter-vehicle distance of 50 m, the detection beams 4a to 4c are too widened and overlap each other, so that the respective reflection beams 5a to 5c by the reflection plate 200 of the front vehicle 101 do not correspond to each other. Beam receiver 7a-
7c may be received, but in this case, as shown in FIG.
As shown in (4), a threshold value is set for the reflected beams 5a to 5c, and reflected beams lower than this threshold value are prevented from being taken into the receivers 7a to 7c (that is, the beams that have been diffused and have reduced luminous intensity). (The end should not be captured and only the effective detection beam with high luminous intensity should be captured.)
It is possible to avoid incorrect position measurement.

In the above case, the normal traveling lane width is 3.
If the distance is 5 m, the distance from the vehicle 100 to 5
The width at the position of 0 m is ≈1.17 m, which is obtained by dividing the driving lane width of 3.5 m into three equal parts, and the divergence angle of the transmission lenses 3a to 3c at this time is ≈2.7 ° [θ = 2 tan ⁻¹ (1.17 / 50)] Becomes

Then, the reflected beams 5a to 5c are received by the receiving lenses 6a to 6c, respectively, and even if they are pulse lasers, when they are emitted at a predetermined beam angle by the transmitting lenses 3a to 3c, they are reflected. Since the light is reflected by the plate 200 with a slight spread, the transmitting lenses 3a to 3c and the receiving lenses 7a to 7c provided on different optical axes as shown in the drawing can perform different operations of transmitting and receiving. It will be possible.

[0021]

As described above, in the front vehicle position detecting device according to the present invention, at least three transmitting means are provided in the front part of the vehicle, and these transmitting means are provided by a single signal source. When pulsed, the pulse lasers are simultaneously emitted toward the front vehicle, and the beam angles of the respective pulse lasers are set so that any one of them is reflected by at least one reflector provided at the rear of the front vehicle. Since it is set and configured to receive and display the pulsed laser reflected by the reflector, it is not necessary to scan the front of the own vehicle by a mechanical oscillating motion having a movable portion weak against vibration, and Since a commercially available component can be used, an inexpensive device can be realized.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration principle of a front vehicle position detection device according to the present invention.

FIG. 2 is a graph diagram illustrating detection of a time difference between detection beam transmission and reflection beam reception, which is executed in the front vehicle position detection device according to the invention.

FIG. 3 is a configuration diagram of an embodiment of a front vehicle position detecting device according to the present invention.

[Explanation of Codes] 1 signal source 2a to 2c detection beam transmitter 3a to 3c transmission lens 4a to 4c detection beam 5a to 5c reflection beam 6a to 6c reception lens 7a to 7c reflection beam receiver 8a to 8c time difference detection unit 9 inter-vehicle distance Distance calculation unit 10 Front vehicle position display unit 11 Inter-vehicle distance display unit 100 Own vehicle 101 Front vehicle 200 Reflector In the drawings, the same reference numerals indicate the same or corresponding parts.

Claims (2)

[Claims] 1. A signal source and at least one reflection provided at the front of the vehicle, each of which emits a pulsed laser simultaneously when energized by the signal source and which is provided at the rear of the vehicle. At least three transmitting means in which the beam angle of each pulse laser is set so that any one of the pulse lasers is reflected by the plate, and each transmitting means for receiving the pulse laser reflected by the reflecting plate A front vehicle position detecting device, comprising: receiving means provided correspondingly; and front vehicle position displaying means provided corresponding to each receiving means. 2. A time difference detecting means for calculating a time difference from the time when the signal source is energized to a time point when an output signal is generated from one of the receiving means, and an inter-vehicle distance from a preceding vehicle based on the time difference. 2. The front vehicle position detecting device according to claim 1, further comprising: a unit that calculates the distance and a unit that receives the output signal from the calculating unit and displays the inter-vehicle distance.