JPH05126949A - Reflector detection device - Google Patents

Abstract

PURPOSE:To prevent continuation of ringing of an alarm signal on a curved road by storing the measured distance before a rapid increase is stored when the rapid increase in detection distance is detected and then by prohibiting generation of the alarm signal when the newly measured distance is larger than the distance which is obtained by subtracting a specified value from the measured distance before the rapid increase. CONSTITUTION:When a road shoulder reflector is detected on a curved road, the measured distance changes in a triangular wave. The minimum measured distance Dc before a rapid increase is stored in a memory within a control means. The control means compares the distance which is obtained by subtracting a specified value R from the stored measured distance Dc with the measured distance De before the rapid increase which is measured newly. When the newly detected distance De is longer than the distance which is obtained by subtracting the specified R from the measured distance Dc where the newly measured distance De is stored, generation of the alarm signal is prohibited. Then, when a newly measured distance Dk becomes shorter than the distance which is obtained by subtracting the specified value R from a stored detection distance Di after prohibiting alarm, alarm prohibition is canceled.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for measuring a distance between a vehicle and an object in front of the vehicle and issuing an alarm when the distance becomes smaller than a safe inter-vehicle distance. The present invention relates to a reflector detection device that does not give an alarm when the arrayed reflectors are detected as a front object.

[0002]

2. Description of the Related Art Conventionally, a device for confirming a safe inter-vehicle distance is widely known. This device emits ultrasonic waves and laser light from the front of the car and reflects it on the object in front,
The distance between the vehicle and the object in front is measured from the time from receiving and emitting this reflected light to the reception, and an alarm is issued when this measured distance becomes smaller than the specified safe inter-vehicle distance. Is configured. When a vehicle equipped with such a device approaches a curve while traveling, the reflected light from the roadside reflector is detected, and this roadside reflector gives an alarm because the distance from the vehicle becomes small. The shoulder reflectors are arranged at predetermined intervals on the shoulders on the outside of a road having a sharp curve, and reflect the light from the headlights to inform the driver that the road is a sharp curve.

When a vehicle equipped with the above-mentioned safety inter-vehicle distance confirmation device approaches a sharp curve, the driver operates the steering wheel along the curve to drive the vehicle between the vehicle and the shoulder reflector even if the vehicle is traveling normally. Since the distance is less than the safe inter-vehicle distance, an alarm is issued. This alarm is very annoying because it goes out while driving on a curve. In order to solve such a problem, for example, JP-A-62-62
A collision warning device and the like shown in Japanese Patent Publication No. 130500 has been proposed. However, such a collision warning device also has various problems.

FIG. 4 is a diagram showing a state in which an automobile detects a roadside reflector while traveling on a curve, and FIG. 5 shows a waveform of a detection signal thereof. 1 is a car, 2 is a sharply curved road, 3 is a plurality of shoulder reflectors arranged along the outer shoulder of the road 2 at predetermined intervals, and 4 is a transmitter (not shown) installed in front of the car. ) Is a beam such as a laser beam emitted from.

The reflected light reflected by the road shoulder reflector 3 after receiving the beam 4 is received, and the distance between the automobile 1 and the nearest road shoulder reflector 3 in front is detected from the time from transmission to reception. It As shown by the dotted line in FIG. 4, when the road shoulder reflector 3a detected by the automobile 1 running out of the range of the beam 4, the distance to the next road shoulder reflector 3b is detected. This detection operation is continuously performed as the automobile 1 travels, and a detection distance having a waveform that changes in a sawtooth shape as the automobile travels as shown in FIG. 5A is obtained. This detection distance first starts to decrease from the detection distance a that has changed abruptly, and when it decreases to the closest detection distance b, this shoulder reflector 3 goes out of the beam 4 and the next shoulder reflector 3 detects it. The detection distance increases sharply. Detection distance is safe distance between vehicles Dr
An alarm will be issued if: The alarm sounds periodically each time the roadside reflector 3 is passed, which is very troublesome.

The above collision warning device stores the detected distance a when it is detected, and stores the detected distance a, and subtracts the detected distance a from the automobile 1 to the shoulder reflector 3 from the detected distance a. The difference (a-i) is monitored, and in the range where the value of the difference is smaller than a predetermined set value corresponding to the distance between the shoulder reflectors corresponding to (a-b), it is determined that the detected object is a stopped object. After that, the warning of the collision warning device is prohibited. That is, even if the detection distances a to b are the safe inter-vehicle distance D
Even if the value becomes equal to or less than r, the alarm is not immediately issued, and when the detection distance difference (a-i) is smaller than the set value, it is determined that the detection object in front is a stationary object and the road shoulder reflector 3, and the collision occurs. Since it is not a predicted object, it is not necessary to issue an alarm, and the generation of an alarm is prohibited.

[0007]

However, on an actual road, the degree of the curve is not a constant curvature,
Since the entrance and exit of the curved road are continuous with the straight road, the curve is gentle and the curvature is small. Therefore,
In the conventional device, when setting a predetermined set value according to the distance between the road shoulder reflectors, if this set value is set according to the condition of the entrance of the curved road, the alarm is smoothly prohibited at the center of the curved road. There is also a problem that if the set value is set according to the condition of the central portion of the curved road, the alarm prohibition cannot be smoothly performed at the entrance and exit of the curve.
This problem can be solved by changing the setting value according to the position of the curved road, but in reality it is difficult to do this,
If you try to realize it, it will be very expensive.

[0008]

DISCLOSURE OF THE INVENTION The present invention provides a reflector detection device having means for measuring the distance of a front object, and means for generating an alarm signal when the distance to the object is equal to or less than a predetermined safe inter-vehicle distance. In the device, a storage means for storing the detection distance before the rapid increase when a rapid increase in the detection distance is detected, a distance obtained by subtracting a predetermined value from the stored detection distance, and a newly detected detection distance before the rapid increase. And a prohibition means for prohibiting the generation of the alarm signal when the new detection distance is larger than the distance obtained by subtracting the predetermined value from the stored detection distance. Further, an alarm prohibition canceling means for canceling the alarm prohibition is provided when the new detected distance becomes smaller than a distance obtained by subtracting a predetermined value from the stored detected distance after the alarm prohibition.

[0009]

[Function] Even if the set value is a constant value, the detection distance before the sudden increase measured last time is compared with the detection distance before the rapid increase measured this time, so that the adjacent detection distances are compared with each other. Since the curved road changes gently even if the curvature changes along the way, the change in the state of the curvature of the curve, the detection interval of the roadside reflector, etc. is not so large between the adjacent detection distances. Therefore, even if a constant set value is used, smooth comparison control can be performed on all curved roads having different curvatures.

[0010]

EXAMPLES The details of the present invention will be described below with reference to examples. FIG. 1 is a block circuit diagram showing an embodiment of the present invention. In the figure, 10 is a well-known distance measuring means installed in front of the vehicle, 4 is a launching beam, 11 is control means including a microcomputer, 12 is a safety distance between the vehicle and the distance measuring object, which is a predetermined safety distance. An alarm means for generating an alarm signal according to alarm information output from the control means 11 when the distance becomes equal to or less than a distance, and a traveling detection means 13 for measuring the traveling distance of the automobile. The traveling detection means 13 is
It outputs one pulse each time it travels a unit distance.
The traveling distance of the automobile can be measured by counting the number of pulses.

The control means 11 includes a storage means, such as a RAM memory, which stores the detection distance before the sudden increase when the sudden increase in the detection distance is detected, and a distance obtained by subtracting a predetermined value R from the stored detected distance. The newly detected detection distance before the sudden increase is compared, and if the new detection distance is greater than the distance obtained by subtracting a predetermined value from the stored detection distance, a prohibition means for prohibiting the generation of an alarm signal, a new An alarm prohibition canceling means for canceling the alarm prohibition is included when the detected distance becomes smaller than the stored detected distance less a predetermined value.

FIG. 2 is a diagram showing the relationship between the traveling distance of the automobile and the detected distance measured by the distance measuring means 10. When the vehicle approaches a curve and a shoulder reflector is detected, the detected distance decreases as the vehicle runs, and when the detected distance becomes equal to or less than the safe inter-vehicle distance Dr, an alarm signal is generated. Further, when the automobile travels and the detection distance reaches the point c, the beam detection shifts to the next road shoulder reflector, so that the detection distance rapidly increases and the detection distance reaches the point d. At this time, the detection distance Dc at the point c, which is the minimum detection distance before the sudden increase, is stored in the memory in the control means 11.

The distance of the road shoulder reflector is detected again from the point d, but the alarm is stopped because the detected distance is greater than the safe inter-vehicle distance Dr at this time. When the detected distance decreases as the vehicle runs and becomes less than the safe inter-vehicle distance Dr, an alarm signal is generated again. When the vehicle travels and the detected distance reaches point e, a sudden increase in the detected distance is detected again, and the detected distance De before the sudden increase at this time is similarly stored in the memory. After that, f point, g
The same measurement and detection operation is performed as at the points h, i, j, k.

Here, the detection distance at point e increases sharply,
At the same time that the detection distance De before the sudden increase is stored in the memory,
The prohibition means performs the comparison operation. In this comparison operation, whether or not De is larger than (Dc-R) is compared. This R is a constant value and is set to, for example, 10 m.
This R is determined according to the actual condition of the curved road, but at all positions of the normal curved road, the detected distance before the sudden increase of this time is calculated from the value obtained by subtracting R from the detected distance before the sudden increase of the previous time. The value of is set to be large. In the example of FIG. 2, since there is a relationship of (Dc-R) <De, it is determined that the road shoulder reflector is a normal one, and the ringing alarm is prohibited. That is, the generation of the alarm signal is stopped. As long as the shoulder reflectors are continuously detected, this condition is satisfied and the alarm prohibition continues. When the above relationship disappears, the alarm prohibition is immediately lifted.

On the other hand, when a part of the curved road is very steep and the shoulder reflectors are arranged so as to be abnormally close to each other, the alarm prohibition is released when the above relationship is not established. In the comparison between the point i and the point k in FIG. 2, the relationship (Di-R)> Dk is established, and the alarm inhibition is released and the alarm signal is generated. In addition,
The warning prohibition is similarly released when there is a foreign object on the curved road or when there is a vehicle approaching ahead. This prohibition release may also be performed when the next sharp increase is not detected when the vehicle travels a certain distance larger than the distance at which the next sharp increase due to the shoulder reflector is predicted after detecting the sharp increase in the detected distance. it can.

Since the detection distance before the previous rapid increase and the detection distance before the current rapid increase are compared, an object that is continuously arranged like a road shoulder reflector is used unless there is a sudden change in the road condition. When detected, even if the curvature of the curved road changes midway, it is possible to accurately determine whether or not the warning should be prohibited over the entire curved road. In this embodiment, the comparison judgment was made from the time of the second sharp increase, but the sharp increase of any number of times of three times or more was detected, and the judgment that it was the road shoulder reflector was further confirmed, and then the comparison was made. You may make a decision.

Next, the operation of the embodiment of the present invention will be described with reference to FIG. In step 20, the distance measuring means 10 measures the distance between the vehicle and the object in front, and in step 21, the detected distance is the safe inter-vehicle distance D.
It is determined whether or not r or less. If the front object is a road shoulder reflector, the detection distance will eventually become less than or equal to the safe inter-vehicle distance Dr. Therefore, in step 22, a warning signal of a front object approach is generated. Eventually, when the detected shoulder reflector comes off the beam to detect the next shoulder reflector, the detection distance sharply increases from point c to point d, as shown in FIG. If it is determined in step 23 that the detection distance has increased sharply,
Proceeding to step 24, the minimum detected distance Dc before the rapid increase is stored in the memory.

Next, at step 25, when it is judged that the next detection distance has suddenly increased at point e, it is omitted, but like step 24, the minimum detection distance D before the sudden increase.
While e is stored in the memory, the routine proceeds to step 26, where the minimum detected distance De before the sudden increase detected this time is
It is determined whether or not it is larger than a value obtained by subtracting a predetermined set value R from the stored detection distance Dc before the sudden increase. When this determination is completed, the lowest detected distance stored at the previous rapid increase is cleared. De for (Dc-R)
Is larger, step 26 becomes YES, and the process proceeds to step 27 to prohibit the alarm. Next, at step 28, it is judged whether or not the new detection distance is larger than the stored detection distance before the previous rapid increase minus R,
It is usually large, so return to the first step. After this,
While the detection distance passes through the points f, g, h, i, j in FIG. 2, the same operation as above is performed. While the vehicle is traveling on a curved road with a normal road shoulder reflector, the state of being determined to be YES in step 26 continues, and the warning signal is continuously prohibited.

When a sharp increase in the detection distance is detected at the k point, the relationship of (Di-R)> Dk is established.
In step 26, it is determined that the next roadside reflector is approaching abnormally due to an abnormal sharp curve, and the result is NO. Then, the process proceeds to step 28, where NO and the alarm prohibition is released in step 29. The alarm prohibition cancellation is executed before that. That is, before a new rapid increase is detected in step 25, a new detection distance is stored in the memory in step 28, which is the result of NO in step 25 (D).
Since it is smaller than i-R), step 28 advances to step 29 to release the alarm inhibition so that the alarm signal can be generated. In this embodiment, since the detected distance is smaller than the safe inter-vehicle distance Dr, the alarm signal is immediately issued.

As described above, before the new detected distance before the rapid increase and the distance obtained by subtracting R from the detected distance before the previous rapid increase are determined in step 26, the new detected distance and the previous detected distance before the new rapid increase are determined. The distance obtained by subtracting R from the detection distance before the sudden increase is compared and judged in step 28, and the alarm prohibition is released. As a result, an alarm signal can be generated by a foreign object on the road or an approaching vehicle ahead.

[0021]

As described above, according to the present invention, even if the curvature of the curved road changes in the middle, the shoulder reflector can be accurately detected by the simple structure, and the warning signal is generated by the shoulder reflector. Can be banned. Further, even when the alarm is prohibited, the alarm prohibition can be canceled when the detected distance approaches abnormally. Therefore, while ensuring the safety of driving by the warning signal, there is an excellent effect that the trouble of detecting the shoulder reflectors and continuing to sound the warning signal when traveling on a curve is eliminated.

[Brief description of drawings]

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

FIG. 2 is a diagram showing a relationship between a traveling distance of an automobile and a detection distance measured by distance measuring means.

FIG. 3 is a flowchart showing the processing of the control means showing the operation of the embodiment of the present invention.

FIG. 4 is a diagram showing a manner in which an automobile detects a roadside reflector while traveling on a curve.

FIG. 5 shows a waveform of a detection signal of a shoulder reflector.

[Explanation of symbols]

 1 Car 2 Road 3 Shoulder Reflector 4 Beam 10 Distance Measuring Means 11 Controlling Means 12 Warning Means 13 Running Detection Means

Claims (2)

[Claims] 1. A distance measuring means for measuring a distance from a vehicle to an object ahead, and an alarm means for generating an alarm signal when the distance to the object measured by the distance measuring means is equal to or less than a predetermined safe inter-vehicle distance. In the provided reflector detection device, a storage means for storing the detection distance before the sudden increase at the time when the distance measuring means detects the sudden increase in the detection distance, and a distance obtained by subtracting a predetermined value from the detection distance stored in the storage means. Comparison with the new detection distance before the sudden increase detected by the distance detection means, and if the detection distance detected by the distance detection means is larger than the stored detection distance minus a predetermined value, the alarm signal is prohibited from being generated. A reflector detecting device, comprising: 2. The alarm prohibition canceling means for canceling the alarm prohibition when the detected distance detected by the distance detecting means becomes smaller than a distance obtained by subtracting a predetermined value from the stored detected distance after the alarm is prohibited. A reflector detection device comprising: