JPH05159199A - Device for detecting approach - Google Patents

Abstract

PURPOSE:To provide the device for detecting approach without offending a driver by stopping the, generation of an alarm when a reflector is detected in a curved line. CONSTITUTION:A light emitting means 1 irradiates the laser beam right and left through a scanning means 2 in the travelling direction of the vehicle. A light receiving means 3 receives the reflected light from the reflection body of the laser beam, and the distance to the reflection body is calculated by a time measurement means 4 and a distance measurement means 5 based on the time from the radiation to the reception. An alarm judgement means 6 judges whether or not the distance to the reflection body changes monotonously according to the change of the scanning angle of the electro-magnetic wave, and when changing monotonously, a reflector in the curved line is judged to stop the generation of an alarm.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an approach detecting device for detecting an approach of an object ahead of a vehicle in a traveling direction, and more specifically, when a reflector provided on a roadside belt is detected while traveling on a curved road. Relates to an approach detection device for stopping the generation of an alarm.

[0002]

2. Description of the Related Art An approach detection device of this type sends a laser beam to the front of a vehicle and receives the reflected light of an object of the laser beam, as disclosed in, for example, Japanese Patent Laid-Open No. 62-130500. The distance to the object is calculated from the time from the transmission to the reception, and the alarm is issued when the distance is less than the predetermined distance.

As shown in FIG. 12, for example, such a conventional approach detection apparatus detects a reflector 91 provided on a roadside belt of a curved road when the vehicle travels on the curved road, and detects this. An alarm is issued when the reflector distance is shorter than a predetermined distance.

However, since such a reflector is not an obstacle, it is desirable not to issue an alarm.
Therefore, when the conventional approach detection device detects a reflector provided on such a curved road, the distance to the reflector changes into a sawtooth shape with the passage of time as shown in FIG. When such a change is detected, it is determined that the road is a curved road on which the reflector exists, and the alarm is stopped for a predetermined time. In addition,
Such a situation occurs especially when only a reflector exists on a curved road.

[0005]

The conventional approach detection device, when it detects that the distance information changes in a sawtooth shape with the passage of time as shown in FIG. 13, determines that the reflector is a curved road reflector. , The alarm is stopped for a predetermined time, but it is necessary to monitor for a certain time or more before detecting that the distance information is sawtooth like this, but the alarm is issued during this fixed time. Will be
There is a problem of giving a driver an unpleasant feeling.

The present invention has been made in view of the above,
It is an object of the present invention to provide an approach detection device that stops issuing an alarm when a reflector is detected on a curved road and does not cause a driver discomfort.

[0007]

In order to achieve the above-mentioned object, the approach detection device of the present invention, as shown in FIG. 1, includes an electromagnetic wave emitting means 51 for scanning left and right while emitting an electromagnetic wave in the traveling direction of a vehicle. A distance calculation unit 52 that receives a reflected wave of the electromagnetic wave from the reflector and calculates a distance to the reflector based on the time from the radiation to the reception; and a change in the scanning angle of the electromagnetic wave emission unit. Stopping means 53 for stopping the generation of an alarm when the distance is monotonously changing
The point is to have and.

[0008]

In the approach detection device of the present invention, electromagnetic waves are emitted in the traveling direction of the vehicle while scanning left and right, reflected waves from the reflector of the electromagnetic waves are received, and reflected based on the time from the emission to the reception. The distance to the body is calculated, and the alarm is stopped when the distance to the reflector is monotonously changing with respect to the change in the scanning angle of the electromagnetic wave.

[0009]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 2 is a block diagram showing the structure of an approach detection device according to an embodiment of the present invention. This approach detection device is a light sending means 1 for sending out a laser beam in the traveling direction of the vehicle, and a laser light sent out from the light sending means 1 is scanned so as to be emitted in the left and right directions in front of the vehicle, for example, a polyhedron. Scanning means 2 composed of a mirror or the like, light receiving means 3 for receiving a reflected wave of a reflector of laser light emitted in the vehicle traveling direction via the scanning means 2, and a light reception signal from the light receiving means 3. And a time measuring means 4 for supplying a laser beam sending command signal to the light sending means 1 and measuring the time from the sending of the laser light from the light sending means 1 to the reception of the received light signal. A distance measuring means 5 for receiving a measurement time from the time measuring means 4 and calculating a distance to a reflector based on the measurement time; and a distance measuring means 5 for receiving distance information from the distance measuring means 5. The scanning angle information of the laser beam, that is, the angle information of the direction in which the reflector is present is received from the canning means 2, and it is determined whether or not an alarm is to be issued based on the angle information and the distance information. The warning judging means 6 and the warning means 7 for issuing a warning according to a command from the warning judging means 6.

The distance to the reflector calculated by the distance measuring means 5 can be obtained by multiplying the time to the reflector measured by the time measuring means 4 by the speed of light and dividing the product by 2.

Next, the operation will be described with reference to the flow chart shown in FIG. In this description, a case will be described in which the vehicle travels on a curved road to the right as shown in FIG. 4A and the reflector 91 provided on the roadside zone of the curved road is detected by laser light.

When the approach detecting device shown in FIG. 2 starts operating, the light transmitting means 1 generates a laser beam based on a command from the time measuring means 4, and the laser beam is repeated by the scanning means 2 in the left and right directions in front of the vehicle. Scanning is performed, and the reflected light of the laser light from the reflector is received by the light receiving means 3 (step 110). The time measuring means 4 receives the reception signal from the light receiving means 3, measures the time from the sending of the laser light by the light sending means 1 to the reception thereof, and supplies the measured time to the distance measuring means 5. The distance measuring means 5 calculates the distance R to the reflector based on this time as described above. The warning determining means 6 takes in the distance information R from the distance measuring means 5 and scans the scanning angle from the scanning means 2, that is, the angle information θ obtained by scanning the laser beam in the left and right direction in front of the vehicle.
Are taken in (step 120).

When the warning determining means 6 receives the distance information R from the distance measuring means 5 and the angle information θ from the scanning means 2, whether or not the distance information R monotonically increases as the angle information θ increases. It is determined (step 130).
Note that, as shown in FIG. 4A, when the present approach detection device detects the reflectors 91 provided at predetermined intervals on the roadside belt of the curved road, the relationship between the distance information R and the angle information θ of the reflector. Assuming that the distances and angles from the near side to the respective reflectors are R1, R2, R3, R4 and θ1, θ2, θ3, θ4 as shown in the figure, as shown in FIG. It can be seen that the distance R monotonically increases.

Distance information R1 to R4 measured in this way
And the angle information θ1 to θ4 is information obtained by one scanning by the scanning means 2, the scanning time by the scanning means 2 is, for example, several tens of milliseconds, and the calculation time in the warning determination means 6 required for the determination is, for example. Since it is a few microseconds, the driver feels almost instantly. It should be noted that about 100 to 200 laser beams are emitted in one scanning of the scanning means 2.

Therefore, when it is detected in step 130 that the distance information R monotonically increases corresponding to the angle information θ, it is not reflected from the preceding vehicle or other obstacles but from the reflector on the curved road. Therefore, in such a case, the alarm is not generated and the process returns to the first step 110.

In step 130, if the distance information R does not monotonically increase in correspondence with the angle information θ,
Since it is not a curved road reflector, it is checked whether it is necessary to give an alarm based on a judgment as to whether the distance R to the reflector is within a predetermined distance or not (step 14).
0). For example, when the distance is equal to or more than the predetermined distance and the alarm is not necessary, the process returns to the first step 110. However, when the distance is within the predetermined distance and the alarm is necessary, the warning means 7 is controlled to perform the alarm for the predetermined time. Is generated (step 15)
0).

FIG. 5 (a) shows a case where the preceding vehicle 92 exists ahead of the curved road to the right. However, even when such a preceding vehicle exists, the approach detection device shown in FIG. Can be applied. In the curved road shown in FIG. 5A, the distances R1, R2, R3, R4 to the left and right rear reflectors provided on the left and right tail lamps of the reflector 91 and the preceding vehicle 92 detected by the approach detection device, and the respective reflectors. With respect to the angles θ1, θ2, θ3, and θ4 with respect to, as shown in FIG. 5B, the distances R3 and R4 to the rear reflector of the preceding vehicle are substantially equal (R3≈R4)
As described above, regarding the relationship between the angle information θ and the distance information R, the distance information R does not monotonically increase in response to the increase in the angle information θ, so it is determined that the reflector is not a curved road reflector and is determined to be an alarm target. can do.

FIG. 6 is a flow chart showing the operation of another embodiment of the present invention. In the flowchart of the figure, an alarm is output when a preceding vehicle existing in the same lane as the own vehicle is within a certain distance. By using this processing, unnecessary calculation can be reduced and processing speed can be improved.

In FIG. 6, the vehicle speed is a predetermined speed, for example, 2
It is checked whether or not the speed is 0 km / h or higher, and if the speed is equal to or higher than the predetermined speed, this process is activated (step 210). When the vehicle speed becomes equal to or higher than a predetermined speed and this processing is activated, the scanning means 2 first performs one scanning (step 220), and as a result, the distance information R and the angle information θ obtained as described above are stored in the memory. (Step 230).

In the distance information R and the angle information θ thus obtained, it is checked whether or not the distance information R monotonically increases as the angle information θ increases (step 240). When the distance information R monotonically increases with respect to the angle information θ, it can be determined that the reflector is a curved road, so the alarm generation is stopped and the process returns to the first step 210, but otherwise. Since it is considered that there is a preceding vehicle, the distance information R and the angle information θ are converted from the polar coordinate system to the (x, y) coordinate system (step 250).

FIG. 7 is a diagram showing the relationship between the polar coordinates consisting of the distance information R and the angle information θ and the (x, y) coordinates. The polar coordinates of the distance information R and the angle information θ are as shown in FIG. It is represented by an angle θ from the x-axis and a distance R from the origin, which is expressed by the following equation in (x, y) coordinates.

X = -Rcos θ y = R sin θ Next, as described above, the distance between the points represented by the (x, y) coordinates, that is, the distance between the reflectors such as the reflector and the preceding vehicle is calculated. Calculate (step 260). Figure 8
(A) and (b) show the points P1, P2, P3, etc. of the reflector, the preceding vehicle, etc., which are thus converted into the (x, y) coordinates.
Although represented by P4, the distances P1-P2, P1-P3, P between the points P1-P2, P1-P3, P are represented by the (x, y) coordinates.
1-P4, P2-P3, P2-P4, P3-P4 can be calculated. Note that in FIG. 8B, P3-P
4 is the distance between the rear reflectors of the preceding vehicle.

It is checked whether or not the distance between the points thus calculated is equal to or less than a predetermined distance, for example, 2 m (meter) (step 270). This distance of 2 m is determined from the point that the distance between the rear reflectors of the vehicle is 2 m or less, and if there is 2 m or less, it can be determined as the rear reflector of the preceding vehicle.

In the check in step 270, 2 m
If there is no following vehicle, it is determined that there is no preceding vehicle, and the process returns to step 210. However, if there is 2 meters or less, it is determined that there is a preceding vehicle, and the coordinates of the midpoint between these two points. Is set as the coordinate (xm, ym) of the preceding vehicle (step 280). In FIG. 8, the distance between the points P3 and P4 is 2 m or less, and it is determined that the vehicle is a preceding vehicle.

When the coordinates (xm, ym) of the preceding vehicle are calculated in this way, in order to check whether or not the position of the next preceding vehicle is in the same lane as the own vehicle, The width is D and xm, which is the x component of the coordinates of the preceding vehicle, is -D /
2 and D / 2, that is, -D / 2 <x
Check m <D / 2 (step 290). If it is not within this range, it can be determined that the preceding vehicle is not in the same lane as the host vehicle, and therefore the alarm is not issued and the process returns to the first step 210.

However, when it is within the range, that is, when the preceding vehicle 92 is in the same lane as shown in FIGS. 9 (a) and 9 (b), the routine proceeds to step 300, where the distance to the preceding vehicle is set. R is calculated from the coordinates (xm, ym) based on the equation shown in step 300. Then, it is checked whether or not the calculated distance R to the preceding vehicle is less than or equal to the predetermined distance Ro (step 310). If it is not less than or equal to the predetermined distance, the process returns to step 210. Issues an alarm (step 320).

FIG. 10 is a diagram showing still another embodiment of the present invention. The embodiment shown in the figure uses a multi-beam instead of the scanning scanning means 2 for scanning the laser light from the light transmitting means 1 to the left and right in the embodiment shown in FIG. Remove the moving parts,
It aims to improve reliability.

In FIG. 10, angles θ1, θ2, θ3, θ
Two beams B1, B2, B3, B in the directions of 4, 5
4 and B5 are generated. By using the five beams in this way, the reflectors 91a, 91b, 9 existing in the roadside zone of the curved road as shown in FIG.
1c with beams B1, B3, B5 at angles θ1, θ3, θ5
Can be detected with. The relationship between the detected distance information R and the angle information θ is shown in FIG. 11 (b).

Although the detection of the reflector can be ensured by increasing the number of the multi-beams described above, the detection error can be prevented by setting the beam wider than that of the scanning radar. ..

[0031]

As described above, according to the present invention,
Scans left and right while radiating electromagnetic waves in the traveling direction of the vehicle,
The reflected wave from this electromagnetic wave reflector is received, the distance to the reflector is calculated based on the time from this radiation to reception, and the distance to the reflector changes monotonically with changes in the electromagnetic wave scanning angle. Since the alarm generation is stopped while the vehicle is running, the alarm is not issued to the reflectors on the curved road, and the driver can comfortably travel on the curved road.

[Brief description of drawings]

FIG. 1 is a diagram corresponding to a claim of the present invention.

FIG. 2 is a block diagram showing a configuration of an approach detection device according to an embodiment of the present invention.

FIG. 3 is a flowchart showing the operation of the approach detection device of FIG.

FIG. 4 is an explanatory diagram showing a relationship between a distance and an angle of a reflector on a curved road.

FIG. 5 is an explanatory diagram showing a relationship between a distance and an angle of a reflector when a preceding vehicle is present on a curved road.

FIG. 6 is a flowchart showing the operation of another embodiment of the present invention.

FIG. 7 is an explanatory diagram for converting polar coordinates into (x, y) coordinates.

FIG. 8 is an explanatory view showing positions of a reflector on a curved road and a rear reflector of a preceding vehicle as points.

FIG. 9 is an explanatory diagram for determining whether the preceding vehicle is in the same lane as the own vehicle.

FIG. 10 is an explanatory diagram of still another embodiment of the present invention, showing that multi-beams are used in the embodiment.

11 is an explanatory diagram showing a case where a reflector on a curved road is detected by the multi-beam shown in FIG.

FIG. 12 is a diagram showing a reflector on a curved road.

FIG. 13 is a diagram showing the distance of a reflector detected on a curved road with respect to time.

[Explanation of symbols]

 1 light transmitting means 2 scanning means 3 light receiving means 4 time measuring means 5 distance measuring means 6 warning judging means 7 warning means

Claims (1)

[Claims] 1. An electromagnetic wave radiating means for scanning left and right while radiating an electromagnetic wave in a traveling direction of a vehicle, and a reflected wave of the electromagnetic wave reflected from a reflector, and a reflector based on the time from the radiation to the reception. Distance calculating means for calculating the distance of
An approach detection device comprising: stop means for stopping the generation of an alarm when the distance is monotonously changing with respect to a change in the scanning angle of the electromagnetic wave emitting means.