JP2884122B2 - Collision warning device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is used in a vehicle. The present invention relates to an improvement in a collision alarm device that is installed in an automobile and measures a distance from a preceding vehicle traveling in front of the own vehicle by a light pulse, calculates a collision risk, and sends a collision alarm to a driver's seat.

[0002]

2. Description of the Related Art An optical transmitter for transmitting an optical pulse and an optical receiver for receiving the reflected light are installed at the front of a vehicle, and a distance from a light emitting and receiving timing to an object to be reflected is calculated. Many devices have been known for a long time to calculate the result by substituting the result into a function and to generate an alarm when it is dangerous. Japanese Patent Publication No. 50-34820 is an example of an old known technique, and Japanese Utility Model Laid-Open Publication No. 2-7158 is an example of a relatively new one.

In the technology related to the collision warning device, the technology for suppressing the generation of unnecessary warning has been considerably advanced. In other words, if the warning level of the collision warning device is set to the safety side where the risk of collision is relatively low, warnings are frequently generated and the meaning of warning to the driver is lost, and conversely, the warning level is reduced to dangerous. If it is set to the side, even if you drive after the alarm sounds, you will not be in time. For this reason, a device has been considered in which, while the alarm level is set to the safe side, among the generated alarms, the alarm when the risk of collision is small is suppressed according to the cause.

A device for suppressing such an alarm is disclosed in Japanese Patent Application Laid-Open No. Sho 62-130500.
This technology is intended to suppress the warning when a vehicle equipped with a collision warning device travels on a curved road and responds to reflectors arranged at regular intervals on a guardrail of the road. It is. That is, the effective range in which the light pulse can be generated and the reflected light can be received is set at a relatively small angle in front of the vehicle so as to detect a preceding vehicle traveling several tens to hundreds of tens of meters ahead. Further, the light wavelength is selected so as to effectively respond to the reflector provided at the rear of the preceding vehicle. When such a vehicle is approaching a curve, it will respond to reflectors arranged at regular intervals on the guardrail, and the alarm will continue to sound while traveling on the curve.

[0005]

In the above-mentioned prior art, in order to identify reflectors arranged at regular intervals, the relative speed with respect to the detected object is equal to the speed of the host vehicle.
In other words, it first identifies that the detected object is a stationary object,
It is determined whether or not the detected object, which is the stationary object, appears at regular intervals, and when it appears at regular intervals, it is regarded as a reflector and the warning is suppressed.
However, if such an operation logic is used, an alarm will be issued assuming that if the reflector is damaged or dirty among a large number of arranged reflectors, it will not appear at regular intervals. . The reflectors actually installed on the roadside are not perfect, and are often missing or damaged. Further, the reflectors are not always arranged at regular intervals on the roadside, and the intervals between the reflectors become denser or rougher as the curve of the road becomes sharp. At this time, it is not possible to identify the reflector with the logic of the above-mentioned prior art. For this reason, each time the vehicle passes through a curve, the collision warning device issues a warning. Furthermore, objects other than reflectors installed on the roadside cannot be identified by the above-mentioned conventional technology.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a collision warning device capable of effectively identifying reflectors and other objects disposed on a roadside and suppressing a warning properly.

[0007]

SUMMARY OF THE INVENTION The present invention provides an optical transmitter for emitting pulsed light, an optical receiver for receiving reflected light of the pulsed light, an emission timing of the optical transmitter, and a reception of the reflected light. A distance circuit for calculating a distance to the detected object from the timing, an output circuit for inputting output information of the distance circuit and executing an operation based on a set function to generate an alarm signal; and In a collision alarm device comprising an alarm circuit that optically and / or acoustically generates an alarm, a detection angle region of the detected object is divided into a plurality of regions for at least one of the optical transmitter or the optical receiver, Distance to the detected object in one area
Are continuously approached over time, and the plurality
The distance to the detected object is continuously
If it close is characterized by comprising a prohibiting means for prohibiting the generation of said alarm.

Preferably, the arithmetic circuit includes means for inputting speed information of the host vehicle, and the function is a function having the speed of the host vehicle and the relative speed of the detected object as elements.

[0009]

According to the present invention, the detection angle region is divided into a plurality (A region, B region, C region,...). (A, B, C,... Or C, B, A,
...), and when the distances appear to be continuous, the detected object is an object that crosses a plurality of detection angle areas, which is an object on the roadside of a curved road and is likely to collide. The occurrence of the alarm is suppressed assuming that the property is small.

[0010] Thus, it is possible to correctly distinguish the reflector or other object arranged on the roadside from the collision object.

[0011]

Next, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing the configuration of the embodiment of the present invention.

An embodiment of the present invention comprises an optical transmitter 1 that emits pulsed light, an optical receiver 3 that receives reflected light of the pulsed light from an object 2 to be detected, an emission timing of the optical transmitter 1, A distance circuit 4 for calculating the distance to the detected object 2 from the timing of receiving the reflected light, and an arithmetic circuit for inputting output information of the distance circuit 4 and executing an arithmetic operation based on a set function to generate an alarm signal 5 and an alarm circuit 6 that generates an alarm optically and / or acoustically based on the alarm signal. Further, as a feature of the present invention, an object to be detected for at least one of the optical transmitter 1 and the optical receiver 3 If the detection angle area 2 is divided into three A, B, and C areas, and the distance to the detected object 2 is sequentially and almost continuously detected over time in the A, B, and C areas, the alarm is issued. Prohibition of occurrence Comprising an alarm generation inhibiting circuit 7 as that means.

The arithmetic circuit 5 is provided with a vehicle speed input means 9 for inputting the speed information of the own vehicle from the vehicle speed detecting means 8, and the function has the speed of the own vehicle and the relative speed of the detected object 2 as elements.

FIG. 2 is a diagram showing a schematic configuration of an optical transmitter and an optical receiver in an embodiment of the present invention. The optical transmitter 1 transmits the light emitted by one light emitter 1a to the detected object 2 via the lens 1b, and the reflected light from the detected object 2 in the three areas A, B, and C is an optical receiver. The light is received by three photoreceptors 3b, 3c, and 3d via the three lenses 3a, and is converted into electric signals.

Next, the operation of the embodiment of the present invention configured as described above will be described. FIG. 3 is a flowchart showing a flow of operation of the embodiment of the present invention, FIG. 4 is a diagram showing a state of light projection on a guardrail in the embodiment of the present invention, and FIG. 5 is a diagram showing a relationship between a detection distance and time in the embodiment of the present invention. FIG.

As shown in FIG. 4, when the vehicle 10 approaches a curve, first, pulse light in the detection angle region A from the optical transmitter 1 irradiates the reflector 12, and the reflected light is received by the optical receiver 3. I do. The distance circuit 4 calculates the distance to the reflector 12 from the light emission timing of the optical transmitter 1 and the light reception timing of the reflected light received by the optical receiver 3, and outputs the information to the arithmetic circuit 5.

The arithmetic circuit 5 inputs the information and the vehicle speed detected by the vehicle speed detecting means 8 from the vehicle speed input means 9 and performs an arithmetic operation based on a function set by using the vehicle speed and the relative speed of the reflector 12 as elements. I do.

As the vehicle 10 travels, the detection angle region shifts to the B region with a certain time difference, the pulse light from the optical transmitter 1 irradiates the reflector 12, and the optical receiver 3 receives the reflected light. Thereafter, similarly, the distance to the reflector 12 is calculated by the distance circuit 4, and the calculation based on the vehicle speed and the relative speed of the reflector 12 is performed by the calculation circuit 5.

When the vehicle further travels, the detection angle range becomes C
The area shifts to the area, and the pulse light from the optical transmitter 1 irradiates the reflector 12, and the optical receiver 3 receives the reflected light. In this case as well, the distance to the reflector 12 is calculated by the distance circuit 4, and the calculation based on the vehicle speed and the relative speed of the reflector 12 is performed by the calculation circuit 5.

FIG. 5 shows the relationship between the distance detected in this manner and time. The distance detected in each of the areas A, B, and C appears with a certain time difference caused by the running of the vehicle 10, and the vehicle travels on a curve. During such operation, such an operation is repeated.

The calculation result in each of the detection angle regions A, B, and C is sent to the alarm generation prohibition circuit 7, and the alarm generation prohibition circuit 7 determines whether the distance to the reflector 12 in each of the detection angle regions A, B, and C is equal. It is determined whether or not they appear almost continuously with the passage of time. This is because, as shown in FIG. 5, three curves A, B and C (actually almost straight lines) are within a certain range on a two-dimensional figure having a horizontal axis as a time axis and a vertical axis as a detection distance. The detection is performed by evaluating that the detection has been performed continuously.

A continuous appearance such as A → B → C corresponds to a case where the steering wheel is turned on a curved road, and in this case, an alarm is prohibited. B → C or B →
Also in the case of appearing as A, it can be configured to prohibit the alarm as if the steering wheel was turned. When passing the preceding vehicle, the warning is automatically prohibited corresponding to the case where the steering wheel is turned.

If they do not appear continuously, it is determined that an object having a high possibility of collision is located in front of the vehicle, and a warning signal is sent to the warning circuit 6, and the warning circuit 6 optically and acoustically responds to the warning signal. Generate an alarm.

When the distance to the reflector 12 appears almost continuously as shown in FIG. 5, the detected object is an object that crosses a plurality of detection angle areas, that is, an object on the road side of a curved road (the book). In the case of the embodiment, the reflector 1
2) It is prohibited to generate an alarm from the alarm circuit on the assumption that there is little possibility of collision.

[0025]

As described above, according to the present invention, an object having no possibility of collision, such as a reflector disposed on the roadside, and an object having a possibility of collision are correctly identified and erroneously determined. This has the effect of reducing the occurrence of alarms and reducing the frequency with which the driver is troublesome.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of an embodiment of the present invention.

FIG. 2 is a diagram illustrating a schematic configuration of an optical transmitter and an optical receiver according to an embodiment of the present invention.

FIG. 3 is a flowchart showing an operation flow of the embodiment of the present invention.

FIG. 4 is a diagram showing a state of light projection on a guardrail according to the embodiment of the present invention.

FIG. 5 is a diagram showing a relationship between a detection distance and time in the embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Optical transmitter 1a Light emitter 1b, 3a Lens 2 Object to be detected 3 Optical receiver 3b, 3c, 3d Light receiver 4 Distance circuit 5 Operation circuit 6 Alarm circuit 7 Alarm generation prohibition means 8 Vehicle speed detection means 9 Vehicle speed input means 10 Vehicle 11 Guardrail 12 Reflector

Claims (2)

(57) [Claims] 1. An optical transmitter for emitting pulsed light, an optical receiver for receiving reflected light of the pulsed light, and a light-emitting timing of the optical transmitter and a light-receiving timing of the reflected light to determine an object to be detected. A distance circuit for calculating a distance, an arithmetic circuit for inputting output information of the distance circuit and executing a calculation based on a set function to generate an alarm signal, and an optical and / or acoustic alarm based on the alarm signal in a collision warning device that includes a warning circuit for generating a detection angle region of the detected object is divided into a plurality of areas for at least one of the optical transmitter or the optical receiver, wherein the detected in one area The distance to the object has passed over time
And continuously approached over the plurality of areas.
And a prohibition unit for prohibiting the generation of the warning when the distance to the detected object is continuously approached. 2. The collision alarm according to claim 1, wherein the arithmetic circuit includes means for inputting speed information of the own vehicle, and the function is a function having the speed of the own vehicle and the relative speed of the detected object as elements. apparatus.