JPH05342500A - Car to car distance detecting device - Google Patents

Abstract

PURPOSE:To accurately detect the distance between cars by outputting the distance to the preceding car as the distance between cars when the traffic lane of it is the same as the self-vehicle. CONSTITUTION:A distance calculating storage means 5 calculates and stores the distance to a reflection body based on the propagation delay time from the radiation to the reception of the electromagnetic wave by the prescribed sweep angle. A reflector detecting means 7 detects a group of reflectors located at one side of the road from among plural reflection bodies. A traffic lane estimating means 9 estimates the traffic lane by assuming the presence of the traffic lane boundary located at a prescribed distance which is set based on the arrangement of the detected group of reflectors. A vehicle discriminating means 11 discriminates the vehicle located in front of the self-vehicle from the reflection body. A traffic lane judgement means 13 judges whether or not the discriminated front vehicle is on the same traffic lane as the self-vehicle. A distance-between-cars output means 15 outputs the distance to the front vehicle as the distance between cars when the front vehicle is judged to be on the same traffic lane as the self-vehicle.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an inter-vehicle distance detecting device for surely detecting an inter-vehicle distance to a preceding vehicle traveling in the same lane as an own vehicle.

[0002]

2. Description of the Related Art As a conventional inter-vehicle distance detecting device, there is, for example, one disclosed in Japanese Patent Laid-Open No. 55-86000. Such a conventional inter-vehicle distance detecting device uses a radar device that emits an electromagnetic wave, receives a reflected wave of the electromagnetic wave, and measures the inter-vehicle distance to a vehicle in front by the propagation delay time from the emission of the electromagnetic wave to the reception. .. However, in such a conventional inter-vehicle distance detecting device, the output direction of the electromagnetic wave output from the radar device is generally fixed to the traveling direction of the vehicle, so that, for example, when traveling on a curved road, it is detected. It was difficult to determine whether the preceding vehicle is the preceding vehicle traveling in the vehicle lane or the adjacent lane. In order to solve the above problems, for example, as disclosed in Japanese Patent Laid-Open No. 61-23985, an electromagnetic wave output from a radar device is scanned within a predetermined angle range to determine the distance and angle to a reflector. There is also proposed a device that detects each of them and determines the traveling lane of the vehicle ahead from the information.

[0003]

However, such a conventional inter-vehicle distance detecting device has the following problems. That is, in the device disclosed in Japanese Patent Laid-Open No. 61-23985, an electromagnetic wave is radiated in the traveling direction of the vehicle while sweeping a predetermined angle range, the reflected wave of the electromagnetic wave reflected by the reflector is received, and even the reflector is received. The distance and direction (angle) of the
It is configured to determine whether or not the preceding vehicle is a preceding vehicle traveling in the same lane as the own vehicle from the respective sweep angles of the reflectors on both sides of the road among the detected reflectors. ing. However, the discrimination logic in the above conventional example has the following problems. (1) It is designed to judge whether the vehicle ahead is traveling on the right side or the left side of the road. That is, it is assumed that there are only two driving lanes, the own driving lane and the adjacent lane, but there are often three or more driving lanes on an actual road, and in that case, a wrong judgment is made. Will end up. (2) It is assumed that the reflectors are present on both sides of the road, but in reality, the reflectors are often present only on one side of the road (outside the curved road), and in that case, it cannot be determined.
Further, when the vehicle is traveling on a curved road, even if there is a reflector on the inside of the road, it may be outside the sweep angle range of the electromagnetic wave and may not be detected. (3) When the traveling road is a curved road, the angle of the reflector is corrected by the steering angle to determine the traveling lane. However, the correction by the steering angle alone is corrected according to the shape of the curved road. Can not. Since the discrimination logic has a problem as described above, it is not possible to accurately detect the inter-vehicle distance to the preceding vehicle particularly in the curved portion of the road, making it difficult to control the inter-vehicle distance to a safe inter-vehicle distance. There was a problem of becoming.

The present invention has been made in order to solve the problems of the prior art as described above, and accurately determines whether or not the vehicle in front is the preceding vehicle on the lane in which the vehicle is traveling, and thus always correct An object of the present invention is to provide an inter-vehicle distance detecting device capable of detecting an inter-vehicle distance.

[0005]

In order to achieve the above object, the present invention is constructed as described in the claims. FIG. 1 is a claim correspondence diagram showing a configuration of the present invention. In FIG. 1, the radiating means 1 and the receiving means 3 correspond to, for example, the laser radar device 21, the laser light sweep device 31, and the laser light sweep direction detection device 33 in the embodiment of FIG. 2 described later. The distance calculation storage unit 5, the reflector detection unit 7, the lane estimation unit 9, the vehicle identification unit 11, the lane determination unit 13, and the inter-vehicle distance output unit 15 correspond to the signal processing circuit 37 of FIG. It is composed of a microcomputer.

[0006]

In FIG. 1, the radiating means 1 radiates an electromagnetic wave in the traveling direction of the vehicle while sweeping a predetermined angle range. Further, the receiving means 3 receives the reflected wave of the radiated electromagnetic wave reflected by the reflector. Further, the distance calculation storage means 5 is
The distance to the reflector is calculated and stored based on the propagation delay time from the emission of electromagnetic waves to the reception for each predetermined sweep angle. Further, the reflector detection means 7 detects a reflector group installed on one side of the road from among the plurality of reflectors. The reflector is a device that is installed mainly on a curved portion on the road side and reflects the light of the headlight of a vehicle, such as a cat's eye. Also, the lane estimating means 9
Estimates a lane assuming a lane boundary line at a predetermined distance preliminarily estimated based on the above-described array of detected reflector groups. Further, the vehicle identifying means 11 identifies a vehicle existing in front of the own vehicle from among the reflectors. Further, the lane judging means 13 judges whether or not the identified front vehicle is in the same lane as the own vehicle. Further, the inter-vehicle distance output means 15 outputs the distance to the front vehicle as the inter-vehicle distance when the lane determining means 13 determines that the front vehicle is in the same lane as the own vehicle.

As described above, in the present invention, a reflector group (for example, a group of three or more reflectors) installed on one side of the road is detected from among the plurality of reflectors, and then, Lanes are estimated based on an array of reflector groups assuming a predetermined lane boundary line. Since the lane width of an expressway or the like is generally a fixed width based on the standard, if the road edge is detected based on the reflector group, the lane can be assumed with high accuracy.
Further, the vehicle existing in front of the host vehicle is identified from among the reflectors, and it is determined whether or not the preceding vehicle is in the same lane as the host vehicle based on the estimated lane. When it is determined that the preceding vehicle is in the same lane as the own vehicle, the distance to the preceding vehicle is output as the inter-vehicle distance. Therefore, even when the road has three or more lanes, or when the reflector is detected only from one side of the road such as the outside of a curved road, the lane of the preceding vehicle can be accurately determined. Therefore, it is possible to realize a more reliable inter-vehicle distance detecting device.

[0008]

FIG. 2 is a system block diagram of an embodiment of the present invention. In this embodiment, after detecting the inter-vehicle distance to the preceding vehicle, the inter-vehicle distance is compared with a predetermined safe inter-vehicle distance corresponding to the vehicle speed, and the inter-vehicle distance is controlled to maintain the actual inter-vehicle distance at or above the safe inter-vehicle distance. The case where the inter-vehicle distance detection device of the present invention is applied to a distance control device is shown.

First, the configuration will be described. In FIG. 2, a laser radar device 21 includes a light transmitter 23 that outputs laser light,
A light receiver 25 that receives the reflected light of the laser light output from the light transmitter 23 and a distance detection circuit 27 that detects the distance to the reflector by the propagation delay time from the laser light output to the reception of the reflected light. .. The laser light output from the light transmitter 23 is controlled by the laser light sweeping device 31 so as to be swept by a predetermined angle to the left and right around the front direction of the vehicle. This laser light sweeping device 31 uses, for example, a mirror to move the laser light in the left-right direction by, for example, an amplitude ±
The sweep is performed at a frequency of 10 Hz and a frequency of 10 Hz. The sweep angle of the laser beam sweeping device 31 is detected by the laser beam sweeping direction detecting device 33 and supplied to the signal processing circuit 37. As the laser beam sweep direction detection device 33, when a step motor is used as a means for controlling the mirror of the laser beam sweep device 31, for example, a sweep angle is output corresponding to the number of pulses for driving the step motor. And the laser beam sweeping device 3 described above.
For example, when a galvanometer type is used as 1, a device for outputting a control signal for controlling the galvanometer as a signal corresponding to the sweep angle. Further, the signal processing circuit 37 is composed of, for example, a microcomputer, and based on the distance supplied from the distance detection circuit 27 of the laser radar device 21 and the sweep angle supplied from the laser light sweep direction detection device 33. A preceding vehicle traveling in the vehicle lane is detected, and an inter-vehicle distance between the host vehicle and the preceding vehicle is calculated. Up to this portion is the portion of the inter-vehicle distance detecting device. Further, the signal processing circuit 37 compares the inter-vehicle distance with a predetermined safe inter-vehicle distance corresponding to the vehicle speed detected by the vehicle speed sensor 39, and based on the difference between the two, the actuator 4
The throttle 43 is controlled via 1 to control the vehicle speed thereby to maintain the inter-vehicle distance with respect to the preceding vehicle at or above the safe inter-vehicle distance. This part is a part of the inter-vehicle distance control device.

The light transmitter 23 outputs, for example, an elongated elliptical or rectangular laser beam having a vertical spread angle of about 4 degrees and a horizontal spread angle of about 0.3 degrees. Is. FIG. 3 is a cross-sectional view of an example of the light transmitter 23. In FIG. 3, the laser light output from the laser diode 47 is spread by the biconvex lens 49,
After being formed into a beam of about 0.3 degrees, it is output as a laser beam having a divergence angle of about 4 degrees in the vertical direction by the cylindrical concave lens 51. As described above, by making the laser light vertically long and slender elliptical or rectangular, it is possible to reliably illuminate a front object over a wide range even on a slope, and to narrow the beam to the left and right. By doing so, the angle with respect to the reflecting object can be detected with high accuracy. The elongated laser beam as described above is output while being swept left and right around the front of the vehicle via the laser beam sweeping device 31. Of the output laser light, the light receiver 25 receives the laser light reflected by the reflector existing in the front of the vehicle, photoelectrically converts it, and amplifies it, and then supplies it to the distance detection circuit 27.

FIG. 4 is a plan view showing lanes and the like on a road for explaining the principle of the present invention. As shown in FIG. 4, the laser light sweep device 31 outputs the light from the light transmitter 23.
The laser light swept by is swept within the angle range of θM to the left and right of the vehicle with respect to the center line 73 of the host vehicle 61, as indicated by alternate long and short dash lines 77 and 79. The amplitude θM of this sweeping angle is, for example, about 10
It is possible to cover general roads almost by setting the degree. Note that in FIG. 4, the own vehicle 61 is the leftmost traveling lane 65 among the three traveling lanes.
In this example, the front vehicle 63 travels in the central traveling lane 67 and no vehicle is present in the rightmost lane 69. Further, a plurality of reflectors are provided at certain intervals on the roadside strip on the left side of the road, forming a reflector group 71. A median strip exists on the further right side of the rightmost lane 69, but no reflector is provided on the median strip. In this invention, it is possible to distinguish the preceding vehicle without a reflector in the median strip,
A case where there is no such case will be described. Further, generally, what can be detected by the laser radar device is a guardrail supporting a reflector in addition to the front vehicle 63 and the reflector group 71. However, the guardrail has a laser beam reflectance higher than that of the reflector. Since it is relatively low and only short distances can be detected, it is omitted in FIG. Also, on an ordinary highway, the width of the lane is about 3.5 m, and the reflector group 7
The distance between the roadside strip where 1 is provided and the lane 65 is 1.
It is 25 m to 2.5 m.

Next, the principle of determining the preceding vehicle will be described before explaining the operation. First, the means for detecting the reflector group installed on one side of the road will be described. FIG. 5 is a characteristic diagram showing the relationship between the sweep angle of the laser beam with respect to the reflector detected by the laser radar device in FIG. 4 and the obtained detection distance. With respect to the sweep angle of the laser light, the vehicle body center axis 73 (see FIG. 4) of the host vehicle is set to 0 degree, and the left side is set to + and swept to the left and right to the alternate long and short dash lines 77 and 79 (see FIG. 4). Further, of the reflector group 71 installed in the left side road band in FIG. 4, symbols are sequentially attached to the reflectors within the laser radar sweep angle range from the one having the shorter detection distance, and the i-th reflector is Ai. (I = 0 to
N; N is the number that can be detected), the data of Ai is
The sweep angle is θi (the angle between the broken line 81 and the vehicle body central axis 73), and the detection distance is Li. When this is illustrated in terms of sweep angle and distance, it becomes a point Ai in FIG. In the case of the above definition, whether or not the detection signal 71 'of FIG. 5 is a signal indicating the reflector group fixed to the roadside zone can be determined from the following two conditions. (1) The time change rate of the detection distance L is measured, and the value thereof is substantially equal to the speed of the host vehicle obtained from the vehicle speed sensor. Actually, it is necessary to consider the change in the angular direction, but the lateral movement amount of the host vehicle is relatively small with respect to the vertical movement amount, and it does not matter much if ignored. .. (2) In three or more adjacent detection signals, the distances between them are almost equal. Those that satisfy both of the above two conditions are judged to be a reflector group installed in the roadside zone of the road.

Next, the detected signal 7 of the detected reflector group
Assuming a lane boundary at a certain distance from the 1'position,
Means for estimating the lane classification will be described. FIG. 6 is a diagram in which the values in FIG. 5 are converted into a vehicle lateral direction and a longitudinal coordinate system. The point Ai in FIG. 5 indicates the angle θi and the distance Li, and when this is converted into the orthogonal coordinate system in the vehicle lateral direction and the front-rear direction, the point Ai becomes the point Ai in FIG. 6. Here, vehicle front-rear direction coordinates: Xi = Li × cos (θi) Vehicle left-right direction coordinates: Yi = Li × sin (θi) Therefore, the detection signal 7 of the reflector group in FIG.
1'is converted into the point sequence 71 "in Fig. 6. As described above, the width of the lane is generally about 3.5 m, and the distance between the roadside belt and the lane is 1.25 m to 2.5 m. Therefore, the lane boundary line 97 between the lane 65 and the lane 67 in FIG.
It is estimated that there is a distance of about 4.8 to 6 m from 1 ″. Specifically, first, as shown in FIG.
A point Bi is obtained in which Ai is perpendicular to the straight line AiAi-1 and is at a constant distance H1 from the point Ai. The distance H1 may be 5 m, for example. The coordinates of the point Bi at this time are (when i = 2 to N): vehicle front-rear direction coordinates: Xi ′ = Xi + H1 / dAi (Y
i-1-Yi) Vehicle left-right direction coordinates: Yi '= Yi-H1 / dAi (X
i−1−Xi) where dAi = √ {(Xi−1−Xi) ² + (Yi−1
-Yi) ² } (when i = 1) Vehicle longitudinal coordinate: X1 '= X1 + H1 / dA1x
(Y1-Y2) Vehicle left-right direction coordinates: Y1 '= Y1-H1 / dA1x
(X1-X2) However, dA1 = √ {(X1-X2) ² + (Y1-Y
2) ² }. Perform the above calculation for each point in the point sequence 71 ″,
The point sequence 83 is obtained. This point sequence 83 is a point sequence assuming the lane boundary line 97 in FIG. Similarly, the point sequence 85 existing at the distance H2 is obtained from the point sequence 83, and by repeating this, the lane boundary lines are sequentially assumed from the left side. At this time, since the distance H2 is equal to the lane width, it may be set to 3.5 m. Then, the area surrounded by the dot array 71 ″ and the dot array 83 is estimated by the estimated lane 91, the area surrounded by the dot array 83 and the dot array 85 is estimated by the lane 93, and the area surrounded by the dot array 85 and the dot array 87 is estimated. Lane lane 95 (same below) These estimated lanes 91, 9
3, 95 are lanes 65, 67, 6 in FIG. 4, respectively.
Equivalent to 9. As described above, the lane segment can be estimated from the arrangement of the reflector groups. Further, the lane in which the vehicle is traveling is determined from the estimated lane divisions, and the determination may be made by using the lane including the origin in FIG. 6 as the traveling lane of the vehicle. In the case of this example, the estimated lane 91 is the own vehicle traveling lane.

Next, a means for determining the traveling lane of the forward vehicle 63 will be described. The forward vehicle 63 is 6 in FIG.
It is illustrated at 3 '. When this is converted into the orthogonal coordinate system of the vehicle lateral direction and the front-rear direction, it is shown as 63 ″ in FIG. 6. Therefore, it is determined which lane section this forward vehicle 63 ″ is in in FIG. do it. In this example, the vehicle is on the estimated lane 93. Finally, the obtained front vehicle 63
The traveling lane 93 is compared with the traveling lane 91 of the own vehicle, and if the same, the forward vehicle 63 is the preceding vehicle traveling in the own lane, and outputs the inter-vehicle distance, and if different, it is traveling in another lane. Therefore, the inter-vehicle distance is not output.

Further, the examples described in FIGS. 4, 5 and 6 are as follows.
Although the vehicle was traveling straight, if it is a curved road, the preceding vehicle can be discriminated as shown in FIGS. 7 and 8. Note that FIG. 7 is a plan view showing lanes and the like on the road for explaining the principle in the case of a curved road, and corresponds to FIG. 4 in the case of a straight road. Further, FIG. 8 is a diagram in which the values of FIG. 7 are converted into an orthogonal coordinate system in the vehicle lateral direction and the longitudinal direction, and corresponds to FIG. 6 in the case of a straight road. In this example, the front vehicle 63 ″ can be determined to be the preceding vehicle traveling in the own lane 91 ′ from FIG. 8. Further, in the examples so far, from the reflector group existing on the left side belt, Although the case of distinguishing the preceding vehicle was explained, in many cases, on actual roads, a reflector group is installed only on the right side due to a left curve, etc. In that case, by estimating from the right side in order, And the preceding vehicle may be determined.

Next, the operation of this embodiment will be described with reference to the flow charts shown in FIGS. The processing procedure shown in FIGS. 9 and 10 is roughly classified into an angle / distance calculating unit 101 that calculates and stores a detection distance for each sweep angle, and a vehicle and a stationary object from the detected angle and distance information. A vehicle discrimination unit 103, and a reflector group detection unit 105 that detects a reflector group installed on the road from the detected stationary object,
A lane estimation unit 107 that estimates the lane division from the placement of the reflector group to determine the traveling lane of the own vehicle, and a vehicle-to-vehicle distance to the preceding vehicle in the own lane by determining whether the preceding vehicle is in the own lane. And a vehicle-interval distance output unit 111 that outputs the calculated inter-vehicle distance when there is a preceding vehicle. The angle / distance calculator 10
1 and the vehicle discrimination unit 103 are shown in FIG. 9, and the reflector group detection unit 105, lane estimation unit 107, headway distance calculation unit 109, and headway distance output unit 111 are shown in FIG.

Next, the processing procedure will be described in detail. angle·
In the distance calculation unit 101, first, steps 121 and 123.
The processing variables k and j are set to 0. The laser sweep is performed from the angle −θM to θM (deg), and the interval is 2
The laser is output every θM / Kmax (deg), and the output is performed Kmax times per sweep. The variable k is the number of the laser output in this one sweep, and the maximum value is Kmax. In addition, the variable j is the number of times the distance is detected in one sweep. Next, at step 125, the traveling vehicle speed of the host vehicle is read from the vehicle speed sensor 39. Further, steps 127 to 141 are a loop, and this loop is performed for each laser output, and when one sweep is completed, the routine proceeds from step 141 to the next vehicle discrimination unit 103.
In this loop, first, the sweep angle θ is read from the laser light sweep direction detection device 33 (steps 127 and 129),
The detection distance L is read from the distance detection circuit 27 (step 131), and if there is no distance detection, the process proceeds to step 139, but if there is a distance detection, the process proceeds to step 135 (step 133). In steps 135 and 137, the data is loaded into the array D (j) only when the distance is detected. Array D
(J) is an array for storing two data of the angle θ and the distance L, and the obtained angle θ and the distance L are input.
After that, the next sweep angle command value is output (step 13
9) If k is less than or equal to Kmax, the current sweep is not yet finished, and therefore the process returns to step 127. If not, all the data obtained by the current sweep is detected and acquired, and the process proceeds to the next vehicle discrimination unit 103.

In the vehicle discrimination unit 103, first, the detected data number Jmax is stored (step 143) and the variables j, m and n are set to 0 for the loop of steps 149 to 163 (steps 145 and 147). ). The variable j indicates the detected data number, m indicates the data number from the moving vehicle, and n indicates the data number from the stationary object. In this loop, first step 1
At 49, the distance change amount ΔL (j) is calculated for each data D (j). The following formula is used for this. ΔL (j) = Lj (−τ) −Lj However, if the time required for one sweep is τ seconds, Lj (−
τ) is the distance data before τ seconds, and the detected distance from the same object one sweep before is used. The change amount of the detection distance per unit time is compared with the own vehicle speed, and if it is not substantially equal to the own vehicle speed, it can be considered that the object is stopped on the road. Make a distinction. | K1 · ΔL (j) −v | ≦ ε1 where k1 and ε1 are constants. If the above equation is satisfied, the detection data D (j) is regarded as a stationary object, and this data is stored as stationary object data S (n) (step 15).
7, 159). On the other hand, when the above equation is not satisfied, the detected data D (j) is regarded as a vehicle traveling ahead and is stored as the forward vehicle data M (m) (steps 153, 155). After that, j is incremented (step 161) and this processing loop is executed until j reaches Jmax, that is, until the data obtained by the current sweep is completed (step 163). At this time, the numbers of the stationary object data and the forward vehicle data are Mmax and Nm, respectively.
It is stored as ax (step 165) and the process proceeds to the next reflector group detection unit 105.

In the reflector group detecting section 105, first, in step 167, variables n and i are set to 0 for the loop processing of steps 169-181. In this loop, first, n is incremented by 1 in step 169, and then in step 171, the data T (n) = (X (n) of the stopped object data S (n) = (θ, L) is coordinate-transformed. , Y (n)). The conversion formula at this time is as follows. Vehicle front-rear direction coordinates: X (n) = L (n) × cos (θ
(n)) Vehicle left-right coordinate: Y (n) = L (n) × sin (θ
(n)) Further, the distance dT (n) between the adjacent stationary objects is obtained (step 173). The calculation formula for this is as follows. dT (n) = √ {(X (n) -X (n-1)) ² + (Y (n) -Y (n-1)) ² } Roads when the distances between adjacent stops are almost equal Since it is regarded as the upper reflector group, in steps 175 to 179 d
T (n) is compared with the previous data dT (n), and if the difference is less than or equal to a predetermined value ε2, this data is discriminated as reflector group A (i). That is, when | dT (n) −dT (n−1) | ≦ ε2 (step 175), A (i) = T (n) is set (steps 177 and 179). This loop is repeated for the number of stop data T (n), and when the number of stop data is reached (step 181), the lane estimation unit 107 thereafter.
Go to.

The lane estimating unit 107 first estimates the lane boundary line by the above-mentioned method of determining the preceding vehicle (step 1).
83). Further, the lane segment is estimated based on this (step 185), and the lane area including the origin is discriminated to discriminate the own lane (step 187).

Next, the inter-vehicle distance calculation unit 109 executes the processing loop of steps 191 to 199 for the number of forward vehicle data M (m). In this loop, first step 1
In 91, m is incremented by 1, and in step 193, the forward vehicle data M (m) is converted into the data C (m) in Cartesian coordinates.
== (X (m), Y (m)) The conversion formula is as follows. Vehicle front-rear direction coordinates: X (m) = L (m) × cos (θ
(m)) Vehicle left-right coordinate: Y (m) = L (m) × sin (θ
(m)) Then, in step 195, it is determined whether or not C (m) is in the own lane, and if it is in the own lane, the inter-vehicle distance Lm is calculated from the detected distance L (m). As the inter-vehicle distance, it is sufficient to output the closest detection distance from the preceding vehicles existing in the own lane. Therefore, the smallest L (m) should be calculated each time the laser light is swept once. Good. Therefore, L
For m, Lm up to the previous loop is compared with L (m) of this time, and the smaller one is set as the inter-vehicle distance Lm of this time. When the preceding vehicle is not in the own lane, the inter-vehicle distance Lm is left as the value of the previous loop.

Finally, the inter-vehicle distance output unit 111 determines from the result of the inter-vehicle distance calculation unit 109 whether or not there is a preceding vehicle (step 201), and if there is a preceding vehicle, outputs the inter-vehicle distance Lm (step 203). ). Then, the process returns to step 121 of the first angle / distance calculation unit 101.

[0023]

As described above, according to the present invention, of the reflectors for which the information on the angle and the distance can be obtained,
Detecting the reflector group installed on one side of the road, estimating the driving lane division by assuming the lane boundary line at a certain distance from the arrangement of the detected reflector group, and estimating the lane division It is configured to determine which lane the preceding vehicle is in, determine whether the lane is the same as the own vehicle, and output the distance to the preceding vehicle as the inter-vehicle distance if the lane is the same as the own vehicle. As a result, even in the case of a road with three or more lanes, when there is a reflector only on one side of the road (outside the curved road), or when only one of the roads can detect the reflector, The lane of the vehicle can be accurately determined. Therefore, there is an effect that it is possible to accurately detect the inter-vehicle distance. Further, if the present invention is applied to an inter-vehicle distance control device that controls a vehicle speed so as to automatically keep the inter-vehicle distance at a safe inter-vehicle distance, it is possible to perform accurate vehicle speed control, and a more reliable inter-vehicle distance control device. Can be realized.

[Brief description of drawings]

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

FIG. 2 is a block diagram of an inter-vehicle distance control device showing an embodiment of the present invention.

3 is a cross-sectional view showing a specific example of the light transmitter shown in FIG.

FIG. 4 is a plan view showing lanes and the like on a road for explaining the principle of the present invention.

5 is a characteristic diagram showing the relationship between the sweep angle of the laser beam with respect to the reflector in FIG. 4 and the obtained detection distance.

FIG. 6 is a diagram in which the values in FIG. 5 are converted into a vehicle lateral direction and a longitudinal coordinate system.

FIG. 7 is a plan view showing lanes and the like on a road for explaining the principle of a curved road.

FIG. 8 is a diagram in which the values in FIG. 7 are converted into a rectangular coordinate system in the vehicle lateral direction and the longitudinal direction.

FIG. 9 is a part of a flowchart showing an example of the contents of calculation in the present invention.

FIG. 10 is another part of the flowchart showing an example of the operation contents in the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Radiating means 3 ... Receiving means 5 ... Distance calculation storage means 7 ... Reflector detecting means 9 ... Lane estimating means 11 ... Vehicle identifying means 13 ... Lane judging means 15 ... Preceding vehicle distance output means 21 ... Laser radar device 23 ... Sending Optical device 25 ... Light receiving device 27 ... Distance detecting circuit 31 ... Laser light sweeping device 33 ... Laser light sweeping direction detecting device 37 ... Signal processing circuit 39 ... Vehicle speed sensor 41 ... Actuator 43 ... Throttle 47 ... Laser diode 49 ... Biconvex lens 51 ... Concave lens 61 ... Own vehicle 63 ... Forward vehicle 71 ... Reflector group 71 ″ ... Point sequence indicating reflector group in calculation 83, 85 ... Point sequence 91, 93, 95 ... Inferred lane boundary line

Claims (2)

[Claims] 1. A radiation means for radiating an electromagnetic wave in a traveling direction of a vehicle while sweeping a predetermined angle range, a receiving means for receiving a reflected wave of the radiated electromagnetic wave by a reflector, and a predetermined sweep angle. In addition, a distance calculation storage unit that calculates and stores the distance to the reflector based on the propagation delay time from the emission of electromagnetic waves to the reception, and a reflector group installed on one side of the road from among the multiple reflectors. A reflector detecting means for detecting a lane, a lane estimating means for estimating a lane assuming a lane boundary line at a predetermined distance preliminarily based on the above-mentioned array of detected reflector groups, and from within the reflector Vehicle identifying means for identifying a vehicle existing in front of the own vehicle, lane determining means for determining whether or not the identified forward vehicle is in the same lane as the own vehicle, and lane determining means for identifying the vehicle in front. Same as own vehicle An inter-vehicle distance detecting device comprising: an inter-vehicle distance output means for outputting the distance to the preceding vehicle as an inter-vehicle distance when it is determined that the vehicle is present in the lane. 2. The inter-vehicle distance detecting device according to claim 1, wherein the reflector group is composed of three or more reflectors.