JP2001357497A - Rear side vehicle monitoring device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rear side vehicle monitoring device capable of surely detecting a following vehicle with the danger of colliding with a present vehicle from behind and demonstrating a sufficiently highly reliable monitoring function. SOLUTION: The traveling track of the present vehicle is estimated from a car speed and a yaw rate (indicated by a thick solid line), a present vehicle lane is imagined from the traveling track (indicated by a chain line) and the vehicle A traveling on the present vehicle lane is selected from rear side vehicles A and B detected by a laser radar. The vehicle A is considered as the following vehicle with the danger of colliding with the present vehicle from behind and an abnormal approach to the present vehicle is monitored.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rear vehicle monitoring device for monitoring a vehicle traveling behind a host vehicle.

[0002]

[Related Background Art] In recent years, as one of active safety (preventive safety) technologies, a lane in which a vehicle travels is determined based on recognition results of a white line by a CCD camera and a reflector (a delineator) installed on a road shoulder. Along with
2. Description of the Related Art A forward vehicle monitoring device has been put to practical use in which a vehicle traveling in a vehicle lane is specified from a preceding vehicle detected by a laser radar, and the vehicle is regarded as a preceding vehicle and monitored. The determination result of this monitoring device is used, for example, for determining whether or not the inter-vehicle time between the own vehicle and the preceding vehicle (set based on the inter-vehicle distance and the relative speed) is appropriate. When it is determined that the vehicle has approached, the driver is alerted by a warning, or the vehicle is automatically decelerated by engine brake generated by throttle-off or downshift.

[0003] A rear-vehicle monitoring device that applies this type of control to a following vehicle that follows the host vehicle and monitors the following vehicle to prevent a rear-end collision with the host vehicle is being studied. However, the situation of monitoring the following vehicle is different from that of the preceding vehicle in the following points, and it has been difficult to put it to practical use. That is, in this case, the own vehicle lane is determined based on the rear image. However, when the vehicle is running on rainy weather, the white line cannot be recognized due to the splash of the own vehicle, and the reflecting surface of the delineator faces rearward. Therefore, the rear image cannot be captured and cannot be used, so that there is a problem that the determination of the own vehicle lane lacks certainty.

[0004] On the other hand, as a technique for monitoring a following vehicle of this type, for example, a rear vehicle monitoring device described in Japanese Patent Application Laid-Open No. 6-258438 discloses a method of monitoring a vehicle in the past several seconds based on vehicle speed and yaw rate. A method that calculates the travel locus and controls the angle of the laser radar so that the beam contacts the inner peripheral side of the road shape obtained from the travel locus when the own vehicle is traveling on a curved lane. is there.

[0005]

The following vehicle which may collide with the own vehicle is a vehicle running on the own vehicle lane and approaching the own vehicle. Should be detected and monitored. However, the rear vehicle monitoring device described in the above-mentioned publication adjusts the angle of the radar device so that the beam reaches the deepest part of the curved road, so that the following vehicle whose detection tends to be delayed due to the curvature of the curved road is used. Is aimed at early detection, and the purpose is clearly different. Therefore, as a result of converging the beam to the innermost part of the curved road, an important following vehicle to be monitored that is already approaching the own vehicle is out of the detection range and cannot be detected. For the following vehicle, it is not possible to determine whether the vehicle is traveling in the own vehicle lane, in other words, whether there is a possibility of a collision with the own vehicle. It was hard to say that it had reliability.

An object of the present invention is to provide a rear vehicle monitoring device capable of reliably detecting a following vehicle that may collide with the own vehicle and performing a sufficiently reliable monitoring function.

[0007]

In order to achieve the above object, according to the first aspect of the present invention, it is provided at a predetermined position of a vehicle,
A radar device for detecting a vehicle behind, a vehicle speed detecting means for detecting a vehicle speed of the own vehicle, a yaw rate detecting means for detecting a yaw rate of the own vehicle, and a traveling locus estimating means for estimating a traveling locus of the own vehicle from the vehicle speed and the yaw rate. And a succeeding vehicle detecting means for detecting a following vehicle traveling around the traveling locus estimated by the traveling locus estimating means, of the rear vehicles detected by the radar device.

Accordingly, the traveling locus of the own vehicle is estimated by the traveling locus estimating means from the vehicle speed detected by the vehicle speed detecting means and the yaw rate detected by the yaw rate detecting means, and the vehicle is traveling near the running locus. The following vehicle is detected by the following vehicle detecting means. Here, a vehicle that may collide with the own vehicle can be regarded as a succeeding vehicle that travels in the vicinity of the traveling locus of the own vehicle. It will be possible to monitor cars without leakage.

According to the second aspect of the present invention, the following vehicle detecting means virtualizes the traveling lane in which the own vehicle is traveling from the traveling locus estimated by the traveling locus estimating means, and the rear vehicle is located within the virtual traveling lane. Is configured to determine that the vehicle is a following vehicle of the own vehicle when traveling. As described above, since the specific vehicle lane is determined and the subsequent vehicle is determined based on the own vehicle lane, it is possible to accurately determine the following vehicle that may collide with the own vehicle.

Further, according to the third aspect of the present invention, there is provided a lane change detecting means for detecting a change in the traveling lane of the own vehicle, and the traveling trajectory estimating means is provided when the lane change is detected by the lane change detecting means. The system is configured to reset past traveling locus data. Therefore, an erroneous traveling locus estimation based on the past traveling locus data before the lane change is prevented beforehand, and the traveling locus estimation accuracy is improved.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention applied to a rear vehicle monitoring device mounted on a passenger car will be described below.
FIG. 1 is a block diagram illustrating the configuration of the rear vehicle monitoring device according to the embodiment. As shown in this figure, an input / output device (not shown) and a storage device (ROM, RAM, BURAM) provided for storing a control program, a control map, and the like are not provided in the interior of the vehicle.
Etc.), an electronic control unit (ECU) 1 including a central processing unit (CPU), a timer counter, and the like.
In the present embodiment, the ECU 1 functions as a traveling locus estimating unit, a following vehicle detecting unit, and a lane change detecting unit. E
On the input side of the CU 1, a laser radar 2 as a radar device installed at the rear of the vehicle and detecting a rear object, a vehicle speed sensor 3 as a vehicle speed detecting means for detecting the vehicle speed of the vehicle, and a yaw rate generated at the time of turning of the vehicle. A yaw rate sensor 4 as a yaw rate detecting means for detecting, and a navigation system 5 as a lane change detecting means mounted on the vehicle are connected. The output side of the ECU 1 is connected to a warning light 6 and a buzzer 7 provided in a driver's seat, and a hazard lamp 8 provided in a front part and a rear part of the vehicle.

Next, a description will be given of a rear vehicle monitoring process executed by the ECU 1. 2 is a flowchart showing a following vehicle monitoring routine executed by the ECU, FIG. 3 is an explanatory diagram showing a procedure for calculating a traveling locus, and FIG. 4 is an explanatory diagram showing a relationship between the traveling locus and the own vehicle lane. For example, when the driver turns on a switch (not shown) of the rear vehicle monitoring device when traveling on a highway or the like, the ECU 1 executes the routine of FIG. 2 at a predetermined control interval, and first, in step S2, the vehicle speed sensor 3 and the yaw rate sensor Enter the information from 4
In the following step S4, a traveling locus is calculated. In the travel locus calculation process, a position before a predetermined time (for example, 0.1 sec) is estimated using the current vehicle position as the origin, and the travel locus of the own vehicle is obtained by sequentially repeating this process.

The process of estimating the traveling trajectory will be described in detail. As shown in FIG. 3, the current traveling direction of the own vehicle is defined as the X direction, and the direction orthogonal thereto is defined as the Y direction.
When (X0, Y0) is the origin, the own vehicle position δ1 = (X1, Y1) before a predetermined time can be specified from the following equations (1) and (2). X1 = X0−L1 · cos θ1 (1) Y1 = Y0−L1 · sinθ1 (2) where L1 is a moving distance from δ1 to δ0, and is detected by the vehicle speed sensor 3. It is obtained by integrating the vehicle speed.
Θ1 is the yaw angle of the own vehicle that has changed from δ1 to δ0, and is obtained by integrating the yaw rate detected by the yaw rate sensor 4.

Further, assuming that the own vehicle position δ1 is the origin and the traveling direction of the own vehicle at this time is the X direction, and the direction orthogonal thereto is the Y direction, the own vehicle position δ2 = (X2,
Y2) can be specified from the following equations (3) and (4). X2 = X1−L2 · cos θ2 (3) Y2 = Y1−L2 · sinθ2 (4) As described above, L2 is the moving distance from δ2 to δ1, θ2
Is the yaw angle of the own vehicle changed from δ2 to δ1. Therefore, the vehicle position δn = (Xn, Yn) which goes back to an arbitrary time point
Can be specified from the following equations (5) and (6).

Xn = Xn-1−Ln · cos θn (5) Yn = Yn−1−Ln · sinθn (6) where Ln is the moving distance from δn to δn-1 and θn Is
This is the yaw angle of the vehicle that has changed from Δn to Δn-1. Therefore, by repeating the above processing, it is possible to estimate a running locus from an arbitrary time to the present as shown in FIG. 3. In the present embodiment, the running locus exceeds 120 m corresponding to the detection range of the laser radar 2. The travel trajectory is estimated as far back as possible (shown by a thick solid line in FIG. 4). Since the own vehicle position is obtained in the order of δn to δ0 in accordance with the traveling of the own vehicle, in the actual estimation process, when a new own vehicle position is determined at predetermined time intervals, the past own vehicle position is set to the origin of the own vehicle position. The calculation contents of the vehicle position are sequentially updated, and the traveling locus is estimated from the own vehicle position.

In a succeeding step S6, the ECU 1 sets a lane width (for example, 4 m) centered on the traveling locus.
Is divided into right and left, thereby imagining a traveling lane in which the vehicle is traveling (indicated by a dashed line in FIG. 4).
In step S8, it is determined whether or not the vehicle has changed lanes. The lane change determination process is performed based on the position information input from the navigation system 5, and when the position of the own vehicle based on the position information deviates from the virtual traveling lane, it is considered that the lane has been changed. Instead of the position information from the navigation system 5, the lane change is determined based on the information from the turn signal operated by the driver at the time of the lane change, or the front of the own vehicle is imaged by the CCD camera. The lane change may be determined when the vehicle crosses the white line recognized from the image.

If no lane change is performed, N is determined in step S8.
When a determination of O (No) is made, the process proceeds to step S10, and the presence or absence of a following vehicle is determined based on information from the laser radar 2. Here, as shown in FIG.
Since the scan angle of the vehicle is about 12 °, not only the rear vehicle A running in the own vehicle lane but also the rear vehicle B in the adjacent lane is detected, but the ECU 1 sends the vehicle B in the adjacent lane to the own vehicle. Because there is no risk of rear-end collision, the vehicle A is not regarded as a subsequent vehicle, but only the vehicle A in the own vehicle lane where rear-end collision is likely is regarded as a subsequent vehicle, and this subsequent vehicle is monitored as described later.

It is to be noted that the following vehicle is determined to run on the own vehicle lane continuously for a certain period of time (for example, 1 second). It is not considered as a following car as it has no effect on the car. When there is no following vehicle, the ECU 1 proceeds to step S10.
Then, the determination of NO is made and the routine ends. Therefore, in this case, monitoring of the following vehicle is not performed.

On the other hand, if it is determined in step S10 that there is a following vehicle (YES), the process proceeds to step S1.
The process proceeds to 2 to determine whether or not the inter-vehicle time T between the host vehicle and the following vehicle is less than a first threshold value T1, and if the determination is NO, the routine ends. The inter-vehicle time T is a predicted time for the following vehicle to reach the own vehicle, obtained from the inter-vehicle distance and the relative speed between the own vehicle and the following vehicle detected by the laser radar 2. That is, in this case, the notification process is not performed on the assumption that there is no risk of a rear-end collision with the own vehicle although the following vehicle exists.

If the determination in step S12 is YES, the warning light 6 is turned on in step S14 to call the driver's attention, and in the following step S16, the inter-vehicle time T between the own vehicle and the following vehicle is set to the second threshold value. It is determined whether it is less than T2 (<T1), and if NO, the routine ends. Step S1
The driver recognizes the presence of a following vehicle approaching the own vehicle by turning on the warning light 6 of 4, and usually takes measures such as changing lanes or increasing the vehicle speed, but such measures were not taken. In this case, the inter-vehicle time T decreases with a decrease in the inter-vehicle distance or the like, so that the determination in step S16 is YES. In this case, the ECU 1 moves to step S18 to activate the buzzer 7 to increase the alert to the driver, and also turns on the hazard lamp 8 to call attention to the following vehicle.

On the other hand, if the lane change is performed while the traveling locus of the own vehicle is sequentially estimated as described above, the determination in step S8 becomes YES, and the ECU 1 proceeds to step S20 and travels. Reset the trajectory estimation process. Specifically, the data of the own vehicle positions δ0 to δn sequentially calculated to be applied to the estimation processing as described above is reset. That is, the data before the lane change is reset because it becomes an error factor when estimating the traveling locus of the new own vehicle lane, and the correct estimation processing is performed based on the data of the new own vehicle position after the lane change. That is, it is considered to be performed.

As described above, in the rear vehicle monitoring device of the present embodiment, the traveling lane of the own vehicle is imagined based on the traveling trajectory estimated from the vehicle speed and the yaw rate. As in the conventional example in which the vehicle lane is determined by recognizing a white line, the vehicle lane can be reliably determined without being affected by the splash of the vehicle during rainy weather.

Further, based on the viewpoint that a following vehicle running in the own vehicle lane may collide with the own vehicle, the laser radar 2 is used.
The vehicle that is traveling in the own vehicle lane is determined from the rear vehicle detected by the vehicle, and the vehicle is regarded as a following vehicle, and an abnormal approach to the own vehicle is monitored based on the inter-vehicle time T. Therefore, the technique disclosed in Japanese Patent Application Laid-Open No. 6-258438, which merely focuses the beam of the laser radar on the deepest part of the curved road, without paying attention to whether or not the vehicle is traveling on the own vehicle lane. In addition, there is no possibility that a following vehicle that may collide with the own vehicle may be missed. As a result, it is possible to always detect the succeeding vehicle to be monitored accurately and to exhibit an extremely high monitoring function. Therefore, when the following vehicle is approaching abnormally, it is possible to execute the notification and surely prevent the rear-end collision with the own vehicle.

Also, 1 / １ ／ of the lane width around the running locus
2 to determine a specific vehicle lane and determine the presence or absence of a following vehicle based on the vehicle lane. Therefore, it is possible to accurately select a following vehicle that may collide with the vehicle, and to reliably monitor the vehicle. Properties can be further improved. In addition, when the lane change is performed, the data of the own vehicle positions δ0 to δn applied to the traveling locus estimation processing is reset, and the estimation processing is performed based on the new own vehicle position data after the lane change. Has resumed. Therefore, erroneous estimation of the traveling trajectory based on the data before the lane change is prevented beforehand, and the estimation accuracy of the traveling trajectory can be improved. As a result, the following vehicle can be accurately selected based on the traveling trajectory, and the monitoring function can be performed. Can be further improved.

Although the embodiment has been described above, aspects of the present invention are not limited to this embodiment. For example, in the above embodiment, the present invention is embodied in a rear vehicle monitoring device mounted on a passenger car, but the type of the vehicle is not limited. For example, the present invention is applied to a work vehicle that works on a road, a bus, or a shoulder of a highway or a median strip. Is also good. In the above embodiment,
The own vehicle lane was estimated from the running trajectory of the own vehicle. However, when there is no splash of the own vehicle such as when driving in fine weather, the own vehicle is recognized by recognizing a white line from the rear image of the own vehicle captured by the CCD camera. The lane can be determined. Therefore, at normal times, the vehicle lane is determined by using the image of the CDD camera, and when it becomes difficult to recognize the white line of the image due to the splash, the processing method is switched to a processing method of estimating the vehicle lane from the traveling locus. Is also good.

Further, in the above embodiment, the vehicle running in the own vehicle lane is monitored as a following vehicle, but the vehicle to be monitored (the vehicle that may collide) may be in a congested state or in a running state of surrounding vehicles. Since it differs depending on the speed and the like, it is not always necessary to limit the vehicle to the vehicle traveling on the own vehicle lane. Therefore, for example, a vehicle traveling on an adjacent lane in addition to the own vehicle lane is monitored as a following vehicle, or all vehicles behind the vehicle detected by the laser radar 2 are monitored as a following vehicle. You may.

On the other hand, in the above embodiment, a laser radar is used as the radar device. However, the present invention is not limited to this, and a radar device for millimeter waves or the like may be used.

[0028]

As described above, the rear vehicle monitoring device according to the first aspect of the present invention is configured to detect the following vehicle traveling near the traveling locus of the own vehicle. It is possible to reliably detect a following vehicle that is likely to have a risk, and to perform a sufficiently reliable monitoring function.

Further, according to the rear vehicle monitoring device of the second aspect of the present invention, since a specific vehicle lane is determined and a subsequent vehicle is determined, the following vehicle which may collide with the vehicle is accurately detected. , The reliability of the monitoring function can be further improved. Further, according to the rear vehicle monitoring device of the third aspect, when the lane change of the own vehicle is performed, the past traveling locus data is reset, so that an erroneous traveling locus estimation is prevented. The accuracy of estimating the traveling locus can be improved, and the following vehicle can be accurately determined based on the traveling locus, so that the reliability of the monitoring function can be further improved.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration of a rear vehicle monitoring device according to an embodiment.

FIG. 2 is a flowchart illustrating a following vehicle monitoring routine executed by an ECU.

FIG. 3 is an explanatory diagram showing a procedure for calculating a traveling locus.

FIG. 4 is an explanatory diagram showing a relationship between a traveling locus and an own vehicle lane.

[Explanation of symbols]

1 ECU (traveling locus estimating means, following vehicle detecting means, lane change detecting means) 2 laser radar (radar device) 3 vehicle speed sensor (vehicle speed detecting means) 4 yaw rate sensor (yaw rate detecting means) 5 navigation system (lane change detecting means)

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Claims (3)

[Claims] 1. A radar device disposed at a predetermined position of a vehicle and detecting a rear vehicle, a vehicle speed detecting means for detecting a vehicle speed of the own vehicle, a yaw rate detecting means for detecting a yaw rate of the own vehicle, Travel path estimating means for estimating the travel path of the own vehicle from the yaw rate; and a following vehicle traveling around the travel path estimated by the travel path estimation means among the rear vehicles detected by the radar device. A rear vehicle monitoring device, comprising: 2. The method according to claim 1, wherein the following vehicle detection means imagined a traveling lane in which the own vehicle is traveling based on the traveling trajectory estimated by the traveling trajectory estimating means. The rear vehicle monitoring device according to claim 1, wherein the rear vehicle monitoring device is determined to be a following vehicle of the own vehicle. 3. A lane change detecting means for detecting a change in a traveling lane of the own vehicle, wherein the traveling trajectory estimating means detects a past traveling trajectory data when the lane change detecting means detects a lane change. 3. The rear vehicle monitoring device according to claim 1, wherein the rear vehicle monitoring device resets the vehicle speed.