JP2019174320A - Vehicle recognition device - Google Patents

Abstract

To provide a vehicle recognition device which determines whether or not a trailing vehicle approaching the host vehicle is doing a motion to pull ahead of the host vehicle.SOLUTION: The vehicle recognition device includes a tail warning ECU 10. The tail warning ECU 10 creates a left box on the basis of a first reflection point group to a trailing vehicle, and creates a right box on the basis of a second reflection point group to a trailing vehicle. The tail warning ECU 10 determines, on the basis of the left and the right boxes, whether or not a trailing vehicle approaching the host vehicle is doing a motion to pull ahead of the host vehicle.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a vehicle recognition device that recognizes the operation of a vehicle following a host vehicle using a radar sensor.

  2. Description of the Related Art Conventionally, a vehicle recognition device that recognizes the operation of other vehicles around the host vehicle using a plurality of radar sensors provided in the vehicle (host vehicle) is known (see, for example, Non-Patent Document 1). . Such a vehicle recognition device is employed in a vehicle rear warning device and other driving support devices.

  The vehicular rear alarm device detects a three-dimensional object (for example, another vehicle) existing behind the vehicle by a plurality of radar sensors (for example, millimeter wave radar). Further, the vehicle rear warning device is referred to as information (hereinafter, “target information”) such as the relative position of the detected three-dimensional object with respect to the host vehicle and the size (width and length) of the three-dimensional object. ) To get.

  Based on the detected target information of the rear vehicle, the vehicular rear warning device may cause a subsequent vehicle approaching the host vehicle to collide with the host vehicle to the extent that it may collide with the host vehicle. It is identified (determined) whether the vehicle is performing a high-speed straight movement or whether the subsequent vehicle is changing the lane and overtaking the own vehicle (overtaking operation). When it is determined that the following vehicle is moving straight ahead, the vehicle rear warning device issues a warning to the driver of the succeeding vehicle (and / or the driver of the host vehicle).

Shinkazu Yoshikazu, 7 others, “Development of rear side obstacle warning system”, Mazda Technical Bulletin, Mazda Motor Corporation, April 2008, NO26 (2008), p.124-130

  By the way, as is well known, the radar sensor increases the radiation angle θh (angle with respect to the central axis Cs) of the radar wave (for example, millimeter wave), and the target information of the detection target (the relative position of the detection target with respect to the host vehicle). ) Has a characteristic that the detection accuracy is lowered (see FIG. 4). Further, as the detection target becomes closer to the radar sensor, the horizontal width D1 of the area in which the target information of the detection target can be detected and the horizontal width of the area in which the target information of the detection target can be detected with high accuracy. D2 becomes narrow.

  Therefore, when the succeeding vehicle is present at a position close to the own vehicle, the vehicle recognition device can detect the relative lateral position of the succeeding vehicle with respect to the own vehicle based on the target information of the succeeding vehicle (relative position with respect to the subject vehicle to be detected). The movement in the direction (lateral movement of the following vehicle) cannot be detected with high accuracy.

  For this reason, it becomes difficult to accurately determine whether or not a succeeding vehicle approaching the host vehicle is performing an overtaking operation overtaking the host vehicle. For this reason, for example, a system that alerts the following vehicle that may collide with the own vehicle or informs the driver of the own vehicle of the existence of the following vehicle that may collide with the own vehicle by an alarm. If it is installed, there is a possibility that a useless warning will be given to the following vehicle that is about to be overtaken.

  The present invention has been made to address the above-described problems. That is, one of the objects of the present invention is vehicle recognition that can accurately determine whether or not a succeeding vehicle approaching the host vehicle is performing an overtaking operation to avoid the host vehicle and pass the host vehicle. The present invention provides an apparatus (hereinafter also referred to as “recognition apparatus of the present invention”).

The recognition device of the present invention is disposed on the left side of a central axis extending in the front-rear direction of the host vehicle (SV), irradiates a radar wave to an area including at least the left rear of the host vehicle, and a plurality of three-dimensional objects of the radar wave. A left rear side radar sensor (11L) for detecting a first reflection point group (h1g) including the reflection point (h1) of
A second reflection point group (which is disposed on the right side of the central axis, irradiates a radar wave to an area including at least the right rear of the host vehicle, and includes a plurality of reflection points (h2) by the solid object of the radar wave ( h2g) for detecting the right rear side radar sensor (11R);
A subsequent vehicle (RV) that is another vehicle approaching the host vehicle from behind the host vehicle is recognized based on the first reflection point group and the second reflection point group, and the recognized subsequent vehicle is the host vehicle. A vehicle recognition unit (10) for determining whether or not an overtaking operation is performed on
With
The vehicle recognition unit
Each time a predetermined update time elapses, based on the first reflection point group for the recognized subsequent vehicle, a boundary region including the first reflection point group is created as a left bounding box (LH),
Each time the update time elapses, based on the second reflection point group for the recognized subsequent vehicle, a boundary region including the second reflection point group is created as a right bounding box (RH),
A first condition that is satisfied when only one area of the left bounding box and the right bounding box is increased by a threshold increase rate or more compared to a predetermined time before,
The area (Sd) of the overlapping area of the left bounding box and the right bounding box is divided by the area (Sa) of the entire area surrounded by the outline of the area where the left bounding box and the right bounding box are combined. A second condition that is satisfied when a certain superposition rate is reduced by a threshold reduction rate or more compared to the predetermined time; and
A third condition that is established when the superposition ratio is equal to or less than a threshold superposition ratio;
When all of the above are established, it is determined that the recognized subsequent vehicle is performing the overtaking operation (determination of “Yes” in step 1220 in FIG. 12),
Configured as follows.

  As will be described in detail later, when the following vehicle approaching the host vehicle is moving straight, both the first reflection point group and the second reflection point group are reflected only by the front end portion of the subsequent vehicle. Based on waves (see FIG. 7). On the other hand, when the succeeding vehicle approaching the host vehicle is performing the overtaking operation, one of the first reflection point group and the second reflection point group is reflected by the reflected wave reflected only by the front end portion of the subsequent vehicle. The other is based on the reflected waves reflected by both the front end portion of the following vehicle and the side portion of the following vehicle (see FIG. 9).

  Therefore, when the succeeding vehicle approaching the host vehicle is moving straight, the position and size of the left bounding box (LH) and the right bounding box (RH) of the succeeding vehicle created by the vehicle recognition unit are substantially the same. Yes (see FIG. 6B). On the other hand, when the following vehicle starts an overtaking operation, the position and size of the left bounding box (LH) are different from the position and size of the right bounding box (RH) (see FIG. 8B). ). Thus, there is a great difference in the position and size of the left bounding box and the right bounding box depending on whether or not the following vehicle approaching the host vehicle is performing the overtaking operation.

  The recognition apparatus according to the present invention allows a succeeding vehicle approaching the host vehicle to pass over based on “the first condition, the second condition, and the third condition” in consideration of such changes in the left bounding box and the right bounding box. It is determined whether or not an operation is being performed. Thereby, this invention recognition apparatus can determine accurately whether the succeeding vehicle which approached the own vehicle is performing the overtaking operation | movement.

  In the above description, in order to help understanding of the present invention, names and / or symbols used in the embodiment are attached to the configuration of the invention corresponding to the embodiment described later in parentheses. However, each component of the present invention is not limited to the embodiment defined by the names and / or symbols.

FIG. 1 is a schematic configuration diagram of a vehicle rear warning device in which a vehicle recognition device according to an embodiment of the present invention is incorporated. FIG. 2A is a plan view showing a detection range of the rear side radar sensor. FIG. 2B is a plan view of the host vehicle and the bounding box. FIG. 3 is a plan view for explaining proper operation and malfunction of the alarm. FIG. 4 is a schematic diagram showing a distribution of detection accuracy of the detection range of the radar sensor. (A) is a top view for demonstrating the straight-ahead operation | movement of a following vehicle. (B) is a top view for demonstrating the overtaking operation | movement of a following vehicle. (A) is a top view for demonstrating the recognition condition of the succeeding vehicle by a radar sensor when a succeeding vehicle performs straight ahead operation | movement. (B) is a top view for demonstrating the bounding box produced | generated when a succeeding vehicle performs a straight-ahead operation | movement. FIG. 7 is a plan view showing a bounding box for a succeeding vehicle that is performing a straight traveling operation. (A) is a top view for demonstrating the recognition condition of the succeeding vehicle by a radar sensor when a succeeding vehicle performs overtaking operation | movement. (B) is a top view for demonstrating the bounding box produced | generated when a subsequent vehicle performs overtaking operation | movement. FIG. 9 is a plan view showing the bounding box for the succeeding vehicle performing the overtaking operation. (A) And (B) is the schematic for demonstrating the calculation method of a superposition rate. FIG. 11 is a flowchart showing a rear alarm control routine executed by the CPU of the rear alarm ECU. FIG. 12 is a flowchart showing a flag setting routine executed by the CPU of the rear warning ECU.

  Hereinafter, a vehicle recognition device according to an embodiment of the present invention will be described with reference to the drawings. This vehicle recognition device is incorporated in a vehicle rear warning device (hereinafter referred to as “the present embodiment device”). In all the drawings of the embodiment, the same or corresponding parts are denoted by the same reference numerals.

(Constitution)
This implementation apparatus is applied to a vehicle (automobile). A vehicle to which the present embodiment is applied may be referred to as “own vehicle” in order to be distinguished from other vehicles. As shown in FIG. 1, this embodiment includes a rear alarm ECU 10, a meter ECU 20, a vehicle state sensor 30, and a CAN (Control Area Network) 50 to which these are connected. The CAN 50 is connected to ECUs that perform various vehicle controls such as an engine ECU, a brake ECU, and a steering ECU (not shown). However, since they are not directly related to the present embodiment, description thereof is omitted. ing.

  These ECUs (including the rear alarm ECU 10 and the meter ECU 20) are electric control units including a microcomputer as a main part, and are connected to each other via a CAN 50 so as to be able to transmit and receive information. ing. The microcomputer includes a CPU, a ROM, a RAM, a nonvolatile memory, an interface I / F, and the like. The CPU implements various functions by executing instructions (programs, routines) stored in the ROM.

  The rear warning ECU 10 is connected to the left rear side radar sensor 11L and the right rear side radar sensor 11R. As shown in FIG. 2A, the left rear side radar sensor 11L is a left corner portion of the rear bumper of the host vehicle SV, and is disposed on the left side of the central axis extending in the front-rear direction of the host vehicle SV. . The right rear side radar sensor 11R is the right corner portion of the rear bumper of the host vehicle SV, and is disposed on the right side of the center axis extending in the front-rear direction of the host vehicle SV. The left rear side radar sensor 11L and the right rear side radar sensor 11R have the same configuration except that the detection areas are different from each other. Hereinafter, when there is no need to distinguish between the left rear side radar sensor 11L and the right rear side radar sensor 11R, these are simply referred to as “rear side radar sensor 11”.

  The detection area L1 of the three-dimensional object of the left rear side radar sensor 11L is a range that extends by a predetermined angle α in the left-right direction with respect to the central axis CL directed diagonally left rearward from the vehicle body left rear corner portion of the host vehicle SV. . The detection area L1 of the three-dimensional object is a range in which the left rear side radar sensor 11L can acquire target information (described later) of the three-dimensional object. The detection area R1 of the three-dimensional object of the right rear side radar sensor 11R is a range that spreads by a predetermined angle α in the left-right direction with respect to the central axis CR directed diagonally right rearward from the vehicle body right rear corner portion of the host vehicle SV. . The detection area R1 of the three-dimensional object is a range in which the right rear side radar sensor 11R can acquire target information (described later) of the three-dimensional object.

  The detection region L1 of the left rear side radar sensor 11L and the detection region R1 of the right rear side radar sensor 11R overlap (overlap) on the rear side of the host vehicle SV. Therefore, a three-dimensional object (for example, another vehicle) behind the host vehicle SV can be detected by the left and right rear side radar sensors 11. The detection distance of the rear side radar sensor 11 is, for example, several tens of meters.

  The rear side radar sensor 11 includes a radar wave transmission / reception unit and a processing unit. The radar wave transmission / reception unit radiates, for example, millimeter wave band radio waves (hereinafter referred to as “millimeter waves”) to a detection region including at least the rear region of the host vehicle SV. Further, the radar wave transmission / reception unit receives a reflected wave generated by the radiated millimeter wave being reflected by a three-dimensional object part (that is, a reflection point). The rear side radar sensor 11 may be a radar sensor that uses radio waves (radar waves) in a frequency band other than the millimeter wave band.

  The processing unit of the rear side radar sensor 11 reflects the phase difference between the transmitted millimeter wave and the received reflected wave, the attenuation level of the reflected wave, the time from transmission of the millimeter wave to reception of the reflected wave, etc. “Reflection point information” representing the relative position and relative speed of the point to the host vehicle SV is calculated. In general, a plurality of reflection points are obtained from one target.

  The processing unit of the rear side radar sensor 11 is connected so as to be communicable with the rear alarm ECU 10. The processing unit of the rear side radar sensor 11 transmits “radar sensor detection information” including “reflection point information” to the rear alarm ECU 10.

  More specifically, the processing unit of the left rear side radar sensor 11L uses radar sensor detection information detected by the left rear side radar sensor 11L (hereinafter referred to as “left radar sensor detection information”). Send. The processing unit of the right rear side radar sensor 11R transmits radar sensor detection information (hereinafter, referred to as “right radar sensor detection information”) detected by the right rear side radar sensor 11R.

  The rear warning ECU 10 receives “left radar sensor detection information” including “reflection point information” from the processing unit of the left rear side radar sensor 11L. “Right radar sensor detection information” including “reflection point information” is received from the processing unit of the right rear side radar sensor 11R.

  The rear warning ECU 10 groups “a plurality of reflection points” that are highly likely to detect one three-dimensional object based on the received “reflection point information”, and sets the group of reflection points that can be grouped into one object. Recognize as a mark. The rear warning ECU 10 calculates the relative position of the target, the relative speed between the host vehicle SV and the target (target information) based on the reflection point information of the reflection point with respect to the recognized target. Note that the rear alarm ECU 10 acquires these values based on xy coordinates defined in advance. The x-axis is a coordinate axis that extends along the front-rear direction of the host vehicle SV so as to pass through the center position in the vehicle width direction of the front end portion of the host vehicle SV and has the front as a positive value. The y-axis is a coordinate axis that is orthogonal to the x-axis and has the left direction of the host vehicle SV as a positive value. The origin of the x-axis and the origin of the y-axis are the center position in the width direction of the front end portion of the host vehicle SV.

  Further, the rear warning ECU 10 uses the reflection point information included in the left radar sensor detection information (information of a plurality of reflection points) and the reflection point information for one target, and each time the update time elapses, the bounding box (Hereinafter referred to as “left bounding box” or simply “left box”).

For the sake of explanation, it is assumed that the points P1 to P6 in FIG. 2B exist as reflection points specified by the “reflection point information” for one target included in the “left radar sensor detection information”.
The left box (LH) indicates, on the specified xy coordinates, “a reflection point group (points P1 to P6 detected only by the left rear side radar sensor 11L) with respect to the recognized target (for convenience,“ It is also referred to as a “first reflection point group”.) Among the reflection points belonging to “)”, it is a rectangle defined by a straight line passing through the following reflection points.
A straight line parallel to the x axis passing through the leftmost reflection point (point P1 in the example of FIG. 2B) A straight line parallel to the x axis passing through the rightmost reflection point (point P5 in the example of FIG. 2B) A straight line parallel to the y-axis passing through the reflection point located at the foremost end (point P3 in the example of FIG. 2B). Parallel to the y-axis passing through the reflection point located at the most rear end (point P6 in the example of FIG. 2B). Straight line

  Therefore, the left box is a boundary region including “a plurality of reflection points (first reflection point group) included in the left radar sensor detection information” for the target recognized based on the left radar sensor detection information. It is specified by the relative position and size with respect to the SV.

  Similarly, the rear alarm ECU 10 uses the reflection point information included in the right radar sensor detection information (information of a plurality of reflection points) and the reflection point information for one target, every time the update time elapses. Create a bounding box (hereinafter referred to as a “right bounding box” or simply a “right box”).

The right box is also referred to as a “reflection point group detected only by the right rear side radar sensor 11R (for convenience sake, a“ second reflection point group ”) with respect to the recognized target on the specified xy coordinates. .) ”Is a rectangle defined by a straight line passing through the following reflection points.
-A straight line parallel to the x-axis passing through the leftmost reflection point-A straight line parallel to the x-axis passing through the reflection point located at the rightmost end-A straight line parallel to the y-axis passing through the reflection point located at the frontmost end-Most A straight line passing through the reflection point located at the rear end and parallel to the y-axis

  Therefore, the right box is a boundary area including “a plurality of reflection points (second reflection point group) included in the right radar sensor detection information” for the target recognized based on the right radar sensor detection information. It is specified by the relative position and size with respect to the SV.

  The rear warning ECU 10 operates as follows in order to prevent the following vehicle RV traveling behind the host vehicle SV from colliding with the host vehicle SV. The rear alarm ECU 10 detects a succeeding vehicle RV (target) approaching the host vehicle SV from behind the host vehicle SV based on radar sensor detection information received from the rear side radar sensor 11. Further, when the rear alarm ECU 10 determines that the detected subsequent vehicle RV is highly likely to collide with the host vehicle SV and that the subsequent vehicle RV is not performing the overtaking operation, the rear alarm ECU 10 notifies the meter ECU 20 via the CAN 50. Send a command.

  In this example, the rear warning ECU 10 causes the subsequent vehicle RV to collide with the own vehicle SV from the present time based on the relative speed Vr of the subsequent vehicle RV with respect to the own vehicle SV and the inter-vehicle distance Dr between the own vehicle SV and the subsequent vehicle RV. A collision prediction time (TTC: Time To Collision) that is a prediction time required until the calculation is calculated.

  More specifically, the rear alarm ECU 10 calculates the collision prediction time TTC of the following vehicle RV by dividing the inter-vehicle distance Dr by the relative speed Vr (inter-vehicle distance Dr / relative speed Vr). The predicted collision time TTC of the subsequent vehicle RV may be calculated in consideration of, for example, the acceleration / deceleration at which the subsequent vehicle RV approaches the host vehicle SV. The predicted collision time TTC of the subsequent vehicle RV is an index of the possibility that the subsequent vehicle RV will collide with the host vehicle SV. It can be estimated that the smaller the collision prediction time TTC, the higher the possibility that the subsequent vehicle RV will collide with the host vehicle SV.

  The rear warning ECU 10 determines that the predicted collision time TTC of the following vehicle RV is equal to or shorter than the rear warning threshold value TTCref, and the rear vehicle RV is performing a straight traveling operation based on “left box LH and right box RH” as will be described later. When it does, it determines with the possibility that the following vehicle RV collided with the own vehicle SV became high, and transmits a back warning instruction | command to meter ECU20 via CAN50.

  The meter ECU 20 is connected to the left and right hazard lamps 21 and the display 22. The meter ECU 20 includes a lamp drive circuit (not shown). When a rear warning command is received from the rear warning ECU 10 via the CAN 50, the right and left hazard lamps 21 are blinked simultaneously. When the meter ECU 20 receives a rear warning command from the rear warning ECU 10, the meter ECU 20 displays a display screen indicating that the rear warning has been performed on the display 22.

  The vehicle state sensor 30 includes a plurality of types of sensors that detect the state of the host vehicle SV, and is connected to the meter ECU 20. The vehicle state sensor 30 includes a vehicle speed sensor that detects a traveling speed of the host vehicle SV, a wheel speed sensor that detects a wheel speed, a longitudinal acceleration sensor that detects a longitudinal acceleration of the host vehicle SV, and a lateral acceleration of the host vehicle SV. And a yaw rate sensor that detects the yaw rate of the host vehicle SV.

  Sensor information detected by the vehicle state sensor 30 is transmitted to each ECU via the meter ECU 20 and the CAN 50. Note that all or part of the vehicle state sensor 30 may be connected to a specific ECU other than the meter ECU 20. Even in this case, the sensor information is transmitted from the specific ECU to another ECU via the CAN 50.

<Overview of operation>
Even when the following vehicle RV approaches the own vehicle SV (when the predicted collision time TTC of the following vehicle RV is equal to or less than the rear warning threshold value TTCref), the present embodiment apparatus determines that the following vehicle RV approaching the own vehicle SV When an overtaking operation for overtaking the host vehicle SV is performed, an alarm to the following vehicle RV is prohibited. The reason is as described below.

  For example, as shown in the situation S0 of FIG. 3, a situation is considered in which the following vehicle RV traveling in the rear position P0 of the host vehicle SV enters the alarm area A from the rear position P0. The alarm area A is a position at the rear end of the host vehicle SV, a position separated from the rear end of the host vehicle SV by a distance d1 (in the negative x-axis direction), and a distance d2 from the left end of the host vehicle SV (y axis). This is a region surrounded by a position separated in the positive direction) and a position separated from the right end of the host vehicle SV by the distance d2 to the right (y-axis negative direction). The distance d1 is a distance at which the predicted collision time TTC is equal to or less than the rear warning threshold value TTCref, and is a distance obtained by multiplying the magnitude of the relative speed Vr of the following vehicle RV by a constant. In other words, when the subsequent vehicle RV enters the warning area A, the collision prediction time TTC is equal to or less than the rear warning threshold value TTCref. In this case, any one of the following situations S1 and S2 may occur.

  The situation S1 is a situation in which the following vehicle RV enters the warning area A by performing a straight traveling operation from the rear position P0. That is, the situation S1 is a situation in which the following vehicle RV approaches the host vehicle SV while performing a straight traveling operation.

  In the situation S2, the following vehicle RV avoids the host vehicle SV and overtakes the host vehicle SV from the left side of the host vehicle SV. It is the situation that entered the area A. That is, the situation S2 is a situation in which the following vehicle RV approaches the host vehicle SV while performing the left overtaking operation.

  Since the situation S1 is a situation in which there is a high possibility that the subsequent vehicle RV travels straight from the rear position P0 and collides with the own vehicle SV, the present embodiment needs to warn the subsequent vehicle RV. Accordingly, it can be said that the alarm operation performed by the present embodiment apparatus on the following vehicle RV in the situation S1 is an appropriate operation.

  On the other hand, the situation S2 is a situation in which it can be estimated that the driver of the succeeding vehicle RV is aware of the preceding own vehicle SV. Therefore, the situation S2 is a situation where the possibility that the following vehicle RV collides with the own vehicle SV is low. is there. Therefore, even if this implementation apparatus is a case where the following vehicle RV approached into the warning area A, it is not necessary to perform a warning (a warning is unnecessary). In this situation S2, if the present embodiment issues a warning to the following vehicle RV, it can be said that the warning is an alarm that should not be performed.

  Therefore, even if the collision prediction time TTC of the subsequent vehicle RV is equal to or less than the rear warning threshold value TTCref, the present embodiment apparatus determines that the subsequent vehicle RV is performing an overtaking operation. Prohibit alarms.

  Here, as shown in FIG. 4, the rear side radar sensor 11 increases the radar wave radiation angle θh (angle with respect to the central axis Cs), and the target information of the detection target (the detection target of the host vehicle SV). (Relative position) detection accuracy decreases. Furthermore, as the detection target becomes closer to the rear side radar sensor 11, the horizontal width D1 of the region in which the target information of the detection target can be detected and the region in which the target information of the detection target can be detected with high accuracy. The lateral width D2 becomes narrow.

  Accordingly, when the subsequent vehicle RV is present at a position close to the own vehicle SV, the present embodiment apparatus determines that the subsequent vehicle RV is based only on the relative position of the subsequent vehicle RV to the own vehicle SV detected by the rear side radar sensor 11. The movement in the horizontal direction (y-axis direction) cannot be detected with high accuracy. Therefore, whether or not the subsequent vehicle RV approaching the host vehicle SV is performing an overtaking operation based on only the relative position movement of the subsequent vehicle RV detected by the rear side radar sensor 11 in the present embodiment. Is determined, the accuracy of the determination is low.

  Therefore, the inventor of the present application, when the succeeding vehicle RV is performing a straight traveling operation (situation S1), the recognition result of the succeeding vehicle RV by the rear side radar sensor 11 and the succeeding vehicle RV starts an overtaking operation ( Situation S2) The recognition result of the following vehicle RV by the rear side radar sensor 11 was examined. As a result, the inventor of the present application has found that the recognition result feature of the subsequent vehicle RV in the situation S1 is different from the recognition result feature of the subsequent vehicle RV in the situation S2.

<< Difference in the characteristics of the recognition result of the following vehicle >>
(Characteristic of recognition result of situation S1)
First, as shown in FIG. 5A, the rear side radar sensor when the following vehicle RV traveling in the rear position P0 moves straight along the arrow a1 and approaches the host vehicle SV. The feature of the recognition result of 11 following vehicles RV is demonstrated.

  In this case, as shown in FIG. 6A, the rear warning ECU 10 specifies the subsequent vehicle RV based on both the left radar sensor detection information and the right radar sensor detection information, and the target of the subsequent vehicle RV. It is detected that the following vehicle RV has entered the warning area A based on the information.

  Further, as shown in FIG. 6B and FIG. 7, the rear warning ECU 10 uses the above-described method based on the reflection point group h1g composed of a plurality of reflection points h1 detected by the left rear side radar sensor 11L. Accordingly, the left box LH is created. The rear warning ECU 10 creates the right box RH according to the above-described method based on the reflection point group h2g composed of the plurality of reflection points h2 detected by the right rear side radar sensor 11R.

  As can be understood from FIG. 7, the reflection points used to create the left box LH are some of the plurality of reflection points h1 detected based on the reflected wave reflected only by the front end portion of the following vehicle RV. It is. Similarly, the reflection points used for creating the right box RH are some of the plurality of reflection points h2 detected based on the reflected wave reflected only by the front end portion of the following vehicle RV.

  Accordingly, since the position of the reflection point used to create the left box LH and the position of the reflection point used to create the right box RH are substantially the same, the left box LH and the right box RH have their positions. And substantially the same in size. Thus, the recognition result of the following vehicle RV in the situation S1 has a feature that the position and size of the left box LH and the position and size of the right box RH are substantially the same.

(Characteristic of recognition result of situation S2)
Next, as shown in FIG. 5B, characteristics of the recognition result of the succeeding vehicle RV of the rear side radar sensor 11 when the succeeding vehicle RV approaches the host vehicle SV by performing the overtaking operation on the left side. Will be described. In the overtaking operation on the left side of the succeeding vehicle RV, the succeeding vehicle RV traveling at the rear position P0 advances leftward from the rear position P0 as indicated by the arrow b1 (the own vehicle SV is avoided from the own vehicle SV). The vehicle is overtaking the host vehicle SV from the left side of FIG.

  Similar to the situation S1, as shown in FIG. 8A, the rear warning ECU 10 identifies the subsequent vehicle RV based on both the left radar sensor detection information and the right radar sensor detection information, and the subsequent vehicle RV Based on the target information, it is detected that the following vehicle RV has entered the warning area A.

  As shown in FIG. 8B and FIG. 9, the rear warning ECU 10 creates the left box LH based on the reflection point group h1g composed of the plurality of reflection points h1 detected by the left rear side radar sensor 11L. . The rear warning ECU 10 creates the right box RH based on the reflection point group h2g composed of the plurality of reflection points h2 detected by the right rear side radar sensor 11R.

  In this case, as shown in the diagram on the left side of FIG. 9, the reflection point used to create the left box LH is a plurality of reflection points detected based on the reflected wave reflected only by the front end portion of the following vehicle RV. any one of h1.

  On the other hand, as shown in the diagram on the right side of FIG. 9, the reflection point used to create the right box RH is a plurality of reflections detected based on the reflected wave reflected by the front end portion of the following vehicle RV. One of the points h2 and one of the plurality of reflection points h2 detected based on the reflected wave reflected by the right side surface portion of the following vehicle RV. For example, the “reflection point located at the foremost or left end of the reflection points obtained from the right rear side radar sensor 11R” for defining the right box RH is a reflection point from the front end portion of the following vehicle RV. . On the other hand, the “reflection point located at the rearmost or rightmost of the reflection points obtained from the right rear side radar sensor 11R” for defining the right box RH is from the right side surface portion of the following vehicle RV. Reflection point.

  That is, when the subsequent vehicle RV moves to the left side to avoid the host vehicle SV, the traveling direction of the subsequent vehicle RV is an oblique left front direction with respect to the front-rear direction of the host vehicle SV. The side part faces the radar wave. Thus, the radar wave emitted from the right rear side radar sensor 11R is reflected by the right side surface portion of the subsequent vehicle RV in addition to the front end portion of the subsequent vehicle RV. Accordingly, the reflection point group h2g used for creating the right box RH includes the reflection point h2 detected based on the reflected wave reflected not only by the front end portion of the following vehicle RV but also by the right side surface portion of the following vehicle RV. Is included.

  Thereby, the length in the x-axis direction of the bounding box (right box RH) opposite to the left side on which the following vehicle RV moves is detected based on the reflected wave reflected by the right side surface portion of the following vehicle RV. It becomes longer by the point h2. As a result, the position and size of the left box LH and the position and size of the right box RH have a great difference. Furthermore, the area of the bounding box (right box RH) on the opposite side to the left side on which the subsequent vehicle RV moves increases.

  When the subsequent vehicle RV approaches the own vehicle SV by performing a right overtaking operation, the length of the left box LH in the x-axis direction is detected based on the reflected wave reflected by the right side surface portion of the subsequent vehicle RV. It becomes longer by the reflected point. As a result, the position and size of the left box LH and the position and size of the right box RH have a great difference. Furthermore, the area of the bounding box (left box LH) on the opposite side to the right side on which the following vehicle RV moves increases.

  As described above, the recognition result of the situation S2 is that the position and size of the left box LH and the position and size of the right box RH are different and the right side or the left side (hereinafter referred to as “passing side”) This is characterized in that the area of the bounding box on the opposite side to that of () is increased.

  The inventor made further studies on the “characteristics of changes in the left box LH and the right box RH” as described above, and obtained the following knowledge.

<Feature 1>
When the succeeding vehicle RV performs the overtaking operation from the rear position P0, only the area of the bounding box on the opposite side to the overtaking side of the left box LH and the right box RH is the predetermined time (for example, 1 second) before. There is a tendency to increase by at least 10% compared to the time. Therefore, when the area of only one of the left box LH and the right box RH of the following vehicle RV traveling inside the warning area A is increased by 10% or more compared to the predetermined time before. The subsequent vehicle RV is considered to have a high possibility of performing the overtaking operation.

<Feature 2>
The inventor examined the “superimposition ratio” calculated according to the following equation (1).

Overlap ratio (%) = {[area Sd of overlapping region] / [area Sa of entire region]} × 100 (%) (1)

The area Sd of the overlapping region is the area of the overlapping region where the left box LH and the right box RH overlap (regions hatched in FIGS. 10A and 10B).
The area Sa of the entire area is an area of the entire area surrounded by the outline of the area where the left box LH and the right box RH are combined (thick solid lines in FIGS. 10A and 10B).

  As described above, when the following vehicle RV is performing a straight traveling operation, the left box LH and the right box RH substantially coincide with each other. In this case, as shown in FIG. 10A, the superposition rate is about 90%. Since this state does not change as long as the following vehicle RV is moving straight, the superposition ratio is maintained at a value of about 90%.

  On the other hand, when the succeeding vehicle RV performs the overtaking operation, as described above, the area of the bounding box on the opposite side to the overtaking side of the left box LH and the right box RH is the area of the overcoming side bounding box. Bigger than. As a result, as shown in FIG. 10B, the superposition ratio becomes a value of 40% or less.

  On the other hand, even in the succeeding vehicle RV that performs the overtaking operation, the vehicle is often performing a straight-ahead operation before the overtaking operation is started. Therefore, the superposition ratio in that case is about 90% as shown in FIG.

  From the above, the overlapping rate of the succeeding vehicle RV that performs the overtaking operation greatly decreases from a value of about 90% to a value of 40% or less before and after the time when the overtaking operation is started. In other words, the superposition rate at a certain point in time of such a subsequent vehicle RV tends to be reduced by at least 30% compared to the superposition rate at a predetermined time before that time (for example, one second before).

  Therefore, when the overlapping rate of the following vehicle RV traveling in the alarm area A is reduced by 30% or more compared to the overlapping rate before a predetermined time, the following vehicle RV performs an overtaking operation. The possibility is considered high.

<Feature 3>
As already described, the superposition rate of the following vehicle RV performing the overtaking operation is a value of 40% or less, and the superposition rate of the subsequent vehicle RV performing the straight traveling operation is a value of about 90%. Therefore, when the overlapping rate of the subsequent vehicle RV traveling inside the alarm area A is, for example, 50% or less, it is highly likely that the subsequent vehicle RV is performing an overtaking operation.

  Based on the above features 1 to 3, the rear warning ECU 10 performs the overtaking operation of the following vehicle RV traveling inside the warning area A when all of the following conditions 1 to 3 are satisfied. It is determined that there is a high possibility. Hereinafter, the time when the latest “left box LH and right box RH” is acquired when the following vehicle RV is traveling inside the warning area A is referred to as “specific time (or current time)”. A time point a predetermined time (for example, 1 second) before the specific time point is simply referred to as a “past time point”. The rear warning ECU 10 updates the “left box LH and right box RH” each time an update time that is equal to or less than a predetermined time described below (preferably sufficiently shorter than the predetermined time) elapses.

Condition 1: “the area of only one of the left box LH and the right box RH” at a specific time point increases by a threshold increase rate (10% in this example) or more with respect to the area at the past time point. thing. This condition is based on Feature 1 above.
Condition 2: The superposition rate at a specific time point is decreased by a threshold reduction rate (30% in this example) or more with respect to the superposition rate at a past time point. This condition is based on the above feature 2.
Condition 3: The superposition rate at a specific time point is equal to or less than a threshold superposition rate (50% in this example). This condition is based on feature 3 above.

  When all of the above conditions 1 to 3 are satisfied, the rear warning ECU 10 performs the overtaking operation of the following vehicle RV approaching the host vehicle SV (the following vehicle RV traveling inside the warning area A). And the warning to the following vehicle RV is prohibited. In other words, the rear warning ECU 10 does not issue a warning even when the predicted collision time TTC of the subsequent vehicle RV is equal to or shorter than the rear warning threshold value TTCref. On the other hand, when at least one of the above conditions 1 to 3 is not established, the rear warning ECU 10 is the following vehicle RV approaching the own vehicle SV (the following vehicle RV traveling inside the warning area A). Determines that the vehicle is moving straight, and issues a warning to the following vehicle RV. Thereby, this implementation apparatus can make low possibility of performing an unnecessary alarm with respect to the succeeding vehicle RV which is performing the overtaking operation among the succeeding vehicles RV which approached the own vehicle SV.

(Specific operation)
Next, a specific operation of the CPU of the rear warning ECU 10 (hereinafter simply referred to as “CPU”) will be described. When the ignition key switch is in the ON position, the CPU executes the rear alarm control routine and the flag setting routine shown in the flowcharts of FIGS. 11 and 12 each time a predetermined time elapses. .

  At a predetermined timing, the CPU starts processing from step 1100 in FIG. 11 and proceeds to step 1105 to transmit from the rear side radar sensor 11 (left rear side radar sensor 11L and right rear side radar sensor 11R). Radar sensor detection information to be acquired.

  Thereafter, the CPU proceeds to step 1110 to determine whether or not the subsequent vehicle RV is detected (recognized) behind the host vehicle SV based on the radar sensor detection information acquired in step 1105. More specifically, the CPU identifies a target (another vehicle) based on radar sensor detection information, and the position and relative speed of the target at the past time, and the current position and relative speed of the target. And whether or not the target approaches the rear end of the host vehicle SV. When the target approaches the rear end of the host vehicle SV, the CPU recognizes the target as the following vehicle RV.

  If the following vehicle RV is not detected, the CPU makes a “No” determination at step 1110 to proceed to step 1195 to end the present routine tentatively.

  On the other hand, if the subsequent vehicle RV is detected, the CPU makes a “Yes” determination at step 1110 to proceed to step 1115, where the relative speed Vr of the subsequent vehicle RV with respect to the host vehicle SV, the host vehicle SV, A predicted collision time TTC (= Dr / Vr) is calculated based on the inter-vehicle distance Dr with the subsequent vehicle RV.

  Thereafter, the CPU proceeds to step 1120 to determine whether or not the subsequent vehicle RV is traveling in the alarm area A, the position of the subsequent vehicle RV (the x-axis direction position and the y-axis direction position), the relative speed Vr, and the rear The determination is based on the alarm threshold value TTCref. Note that the above-described distance d1 of the alarm area A is a product of Vr and TTCref.

  When the subsequent vehicle RV is not traveling in the alarm area A, the possibility that the subsequent vehicle RV collides with the host vehicle SV is low. In this case, the CPU makes a “No” determination at step 1120 to directly proceed to step 1195 to end the present routine tentatively. Accordingly, no warning is given to the following vehicle RV.

  On the other hand, when the following vehicle RV is traveling in the warning area A, the CPU makes a “Yes” determination at step 1120 to proceed to step 1125, where the value of the overtaking flag F is “0”. It is determined whether or not. Note that the value of the overtaking flag F is set to either “0” or “1” by a flag setting routine described later. The overtaking flag F is set to “1” when it is estimated that the succeeding vehicle RV is performing the overtaking operation, and is set to “0” otherwise. Further, the overtaking flag F is set to “0” in an initialization routine executed by the CPU when the ignition key switch (not shown) of the host vehicle SV is changed from the off position to the on position.

  When the value of the overtaking flag F is “0”, the CPU makes a “Yes” determination at step 1125 to proceed to step 1130, and transmits a rear warning command to the meter ECU 20. Thereby, meter ECU20 blinks hazard lamp 21, and issues a warning to succeeding vehicle RV.

  On the other hand, when the value of the overtaking flag F is not “0” (when it is “1”), the CPU makes a “No” determination at step 1125 to directly proceed to step 1195 to temporarily execute this routine. finish. Therefore, the warning for the following vehicle RV is not performed (the warning for the following vehicle RV is prohibited).

  On the other hand, at a predetermined timing, the CPU starts processing from step 1200 in FIG. 12 and proceeds to step 1205, where the rear side radar sensor 11 (the left rear side radar sensor 11L and the right rear side radar sensor 11R). The radar sensor detection information transmitted from is acquired.

  Thereafter, the CPU proceeds to step 1210 and determines whether or not the subsequent vehicle RV is detected behind the host vehicle SV based on the radar sensor detection information acquired in step 1205 in the same manner as in step 1110.

  If the succeeding vehicle RV is not detected, the CPU makes a “No” determination at step 1210 to proceed to step 1215 to set the value of the overtaking flag F to “0”. Thereafter, the CPU proceeds to step 1295 to end the present routine tentatively.

  On the other hand, if the subsequent vehicle RV is detected, the CPU makes a “Yes” determination at step 1210 to proceed to step 1220 to determine whether or not the subsequent vehicle RV is performing an overtaking operation. Specifically, the CPU generates a left box LH and a right box RH by executing a routine (not shown) every time “an update time shorter than a predetermined time” elapses, and associates the generated time with the generated time. I remember it. In this step 1220, the CPU performs the above operation based on the information on the left box LH and the right box RH at the present time (latest) and the information on the left box LH and the right box RH generated at the past time point (one second ago). It is determined whether or not all of the conditions 1 to 3 are satisfied.

  When all of the conditions 1 to 3 are satisfied, it is highly likely that the following vehicle RV is performing an operation of overtaking the host vehicle SV. Accordingly, in this case, the CPU makes a “Yes” determination at step 1220 to proceed to step 1225 to set the value of the overtaking flag F to “1”.

  In this case, as described above, in the rear warning control routine, the CPU is in the case where the subsequent vehicle RV is traveling in the warning area A (that is, the predicted collision time TTC with the subsequent vehicle RV is the rear warning). Even if the threshold value is TTCref or less), no warning is given to the following vehicle RV. Thereafter, the CPU proceeds to step 1295 to end the present routine tentatively.

  On the other hand, when at least one of the above conditions 1 to 3 is not satisfied, the succeeding vehicle RV is not performing the overtaking operation of overtaking the own vehicle SV (the succeeding vehicle RV is performing the straight traveling operation). High nature.

  Therefore, in this case, the CPU makes a “No” determination at step 1220 to proceed to step 1215 to set the value of the overtaking flag F to “0”. Thereafter, the CPU proceeds to step 1295 to end the present routine tentatively.

(effect)
The present embodiment described above has the following effects. That is, the present embodiment determines whether the following vehicle RV approaching the host vehicle SV is performing a straight-ahead operation or an overtaking operation by determining whether the left rear side radar sensor 11L or the right rear side radar is operating. The determination is based on the difference in the recognition result of the sensor 11R. As a result, the present embodiment can accurately determine whether the following vehicle RV approaching the host vehicle SV is performing a straight-ahead operation or an overtaking operation. As a result, the present embodiment can reduce the possibility of issuing an unnecessary alarm to the following vehicle RV that is approaching the host vehicle SV but is about to pass the host vehicle SV.

  As mentioned above, although embodiment of this invention was described concretely, this invention is not limited to the above-mentioned embodiment, Various modifications based on the technical idea of this invention can be employ | adopted.

  For example, in step 1110 and step 1210, the CPU compares the past traveling locus of the host vehicle SV with the movement locus of the target, and determines that the following vehicle RV exists when both are similar. Also good. Further, in step 1120, the CPU determines whether or not the subsequent vehicle RV has a warning by determining whether or not the predicted collision time TTC is less than or equal to the rear warning threshold value TTCref and the lateral position of the subsequent vehicle RV is within a predetermined range. You may determine whether it exists in an area. Further, the CPU may execute a step of “determining whether or not the subsequent vehicle RV has just entered the continuation area” between step 1210 and step 1220. In this case, the CPU proceeds to step 1220 when the subsequent vehicle RV has just entered the continuation area, and proceeds to step 1215 otherwise.

DESCRIPTION OF SYMBOLS 10 ... Back warning ECU, 11L ... Left rear side radar sensor, 11R ... Right rear side radar sensor, 20 ... Meter ECU, 21 ... Hazard lamp, 22 ... Indicator, 30 ... Vehicle state sensor, LH ... Left box, RH ... Right box, RV ... Subsequent vehicle, SV ... Own vehicle

Claims (1)

A first reflection point that is disposed on the left side of a central axis extending in the front-rear direction of the host vehicle, radiates a radar wave to an area including at least the left rear of the host vehicle, and includes a plurality of reflection points by a three-dimensional object of the radar wave Left rear side radar sensor to detect the group;
A right side that is disposed on the right side of the central axis, irradiates a radar wave to an area including at least the right rear of the host vehicle, and detects a second reflection point group including a plurality of reflection points by the solid object of the radar wave. A rear side radar sensor,
A subsequent vehicle that is another vehicle approaching the host vehicle from the rear of the host vehicle is recognized based on the first reflection point group and the second reflection point group, and the recognized subsequent vehicle overtakes the host vehicle. A vehicle recognition unit that determines whether or not
With
The vehicle recognition unit
Each time a predetermined update time elapses, a boundary region including the first reflection point group is created as a left bounding box based on the first reflection point group for the recognized subsequent vehicle,
Each time the update time elapses, based on the second reflection point group for the recognized subsequent vehicle, a boundary region including the second reflection point group is created as a right bounding box,
A first condition that is satisfied when only one area of the left bounding box and the right bounding box is increased by a threshold increase rate or more compared to a predetermined time before,
The overlap ratio, which is a value obtained by dividing the area of the overlapping region of the left bounding box and the right bounding box by the area of the entire region surrounded by the outline of the region combining the left bounding box and the right bounding box, A second condition that is satisfied when the threshold value reduction rate is reduced by more than a threshold reduction rate compared to a predetermined time; and
A third condition that is established when the superposition ratio is equal to or less than a threshold superposition ratio;
When all of the above are established, it is determined that the recognized subsequent vehicle is performing the overtaking operation.
A vehicle recognition device configured as described above.

Images