JP2000149197A - Vehicle circumference monitoring device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide useful information to a driver all the times by setting a distance threshold based on clearance information in the lateral direction of a vehicle. SOLUTION: A distance threshold Rth being the reference of deciding whether or not other vehicles exist in a dead angle area ED is changed in accordance with clearance Xc in order to detect following vehicles having a dead angle approaching rate being equal to or more than a fixed level which is hard for a driver to visually recognize at an early stage. As for a following vehicle C11 traveling at a position having relatively small clearance Xc1, because decision is made according to whether or not the vehicle C11 exists in the area ED with a small distance threshold Rth1 as reference, it is possible to decide that it exists in the area ED when the dead angle approaching rate becomes equal to or more than a fixed value. As for a following vehicle C12 traveling at a position having relatively large clearance Xc2, since whether or not the vehicle C12 exists in the area ED is judged with a relatively large threshold Rth2 as reference, possible to judge the approaching to the area ED at a relatively early stage.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle periphery monitoring device, and more particularly to a vehicle periphery monitoring device that determines whether or not another vehicle exists in a blind spot area behind a vehicle.

[0002]

2. Description of the Related Art Conventionally, when another vehicle is present in a blind spot area behind a vehicle, an alarm or the like is issued to notify a driver that a vehicle is present behind the vehicle. (For example, Japanese Patent Laid-Open No. 8-241)
49). In this conventional device, a plurality of laser beams are applied to a blind spot area of a driver, which cannot be visually recognized by a rear side mirror on the vehicle side, and reflected light is detected. And a laser beam (pulse beam)
The distance from another vehicle traveling behind the vehicle is measured based on the difference between the irradiation timing and the light reception timing of the vehicle, and an alarm or the like is issued when the distance becomes equal to or less than a predetermined value.

By issuing an alarm in this manner, the driver can know the presence of another vehicle behind the vehicle that cannot be visually recognized by the door mirror. It is possible to reduce the burden of checking the rear.

[0004]

By the way, as shown in FIG. 1, for example, as shown in FIG. By irradiating a laser beam or a radiating radar beam such as a microwave, the distance to another vehicle that has entered the blind spot area Ed is detected,
When the distance becomes equal to or less than a predetermined value (hereinafter, referred to as a distance threshold Rth), another vehicle moves to the blind spot area ED.
The conventional vehicle periphery monitoring device that determines that the vehicle has entered the vehicle and issues an alarm or the like has the following disadvantages.

[0005] When a distance threshold Rth, which is a criterion for issuing an alarm or the like, is set to a relatively large value R1, a vehicle C1 (P1) traveling at a position relatively close to the host vehicle Co in the lateral direction X and a lateral direction are set. It can be determined relatively early that both the vehicle C2 (P1) traveling at a relatively distant position of X and the vehicle C2 (P1) have entered the monitoring area ED. Running vehicle C1 (P1)
Regarding, an alarm is issued even though the driver can almost visually recognize the door mirror. In such a case, the driver feels the alarm troublesome.

On the other hand, if the distance threshold Rth is set to a relatively small value R2, the vehicle C1 (P2) traveling at a position relatively close to the host vehicle Co in the lateral direction X becomes difficult to see through the door mirror. Although it is possible to accurately determine the approach to the blind spot area ED when
Regarding the vehicle C2 (P2) that travels relatively far in the lateral direction X from the host vehicle Co, it is difficult to determine whether the vehicle C2 (P2) has already entered the blind spot area ED.

As described above, the distance to another vehicle traveling behind the vehicle is measured by a radar or the like, and another blind spot area ED in the rear of the vehicle is determined depending on whether the distance is equal to or less than the distance threshold Rth. In a conventional vehicle periphery monitoring device that determines whether or not a vehicle is present, a warning or the like based on the determination result is not necessarily generated by the driver depending on the position of the other vehicle in the lateral direction X. It is not useful information.

In addition, even if another vehicle is present behind the vehicle as described above, unless the driver intends to change lanes to enter the lane where the other vehicle exists. It is not necessary to issue an alarm. in this way,
If the driver does not intend to change lanes, such an alert will not be useful information for the driver. Furthermore, the appropriate angle of the door mirror differs depending on the seating position of the driver. When the angle of the door mirror is changed, the blind spot area behind the vehicle changes. For this reason, when the radar monitoring area is set wide considering the fluctuation range of the angle of the door mirror, even if the vehicle behind enters the monitoring area, depending on the driver's seating position, the rearview mirror may be used. In some cases, the vehicle can be visually recognized. In this case as well, an alarm or the like based on the entry of another vehicle into the monitoring area becomes troublesome for the driver.

Accordingly, an object of the present invention is to provide a vehicle periphery monitoring device which monitors a vehicle traveling in a blind spot area behind the vehicle and provides information to a driver according to the monitoring result. The purpose is to always provide useful information to the driver.

[0010]

In order to solve the above-mentioned problems, the present invention is directed to a predetermined area including a blind spot area of a mirror having a rear peripheral portion of a vehicle as a visible range. Is a monitoring range, the distance to the following vehicle within the monitoring range is measured, and when the measured distance becomes equal to or less than a distance threshold that is a reference value, it is determined that the following vehicle exists in the blind spot area. In the vehicle periphery monitoring device, a clearance information acquisition unit that acquires clearance information corresponding to the distance between the vehicle and the following vehicle in the vehicle lateral direction, and the vehicle in the vehicle lateral direction based on the acquired clearance information. Reference value setting means is provided for setting a distance threshold such that the value decreases as the distance to the following vehicle decreases.

[0011] The blind spot area of the mirror, whose visible area is the rear peripheral portion of the vehicle, becomes farther away from the vehicle as it goes backward from the vehicle (see area ED in FIG. 1). In the vehicle periphery monitoring device as described above, it is determined whether or not the following vehicle exists in the blind spot area using a smaller distance threshold as the distance between the vehicle and the following vehicle in the vehicle lateral direction becomes smaller. Therefore, for a following vehicle having a small distance to the vehicle in the vehicle lateral direction, when the following vehicle approaches the vehicle and more portions enter the blind spot area,
It is determined that the measured distance has become equal to or smaller than the distance threshold at which the value becomes small.

[0012] Further, for a succeeding vehicle having a large distance from the vehicle in the lateral direction of the vehicle, even when the measured distance is relatively large, a state in which many parts have entered the blind spot area is maintained. Therefore, even when the measured distance is relatively large, it is determined that the measured distance has become equal to or less than the relatively large value of the distance threshold when the subsequent vehicle has entered a larger part of the blind spot area.

[0013] Based on the above determination results,
In a state where a relatively large portion of the following vehicle is included in the blind spot area, that is, in a state where it is difficult for the driver to visually recognize the following mirror, it is possible to notify that the following vehicle exists in the blind spot area. Become. In view of the fact that clearance information can be easily acquired, the present invention provides, in the vehicle surroundings monitoring device, the clearance information acquiring means, as described in claim 2, wherein a predetermined point of the vehicle is It has relative speed change obtaining means for obtaining a change in relative speed when a following vehicle approaches, and is configured to use the magnitude of the change in relative speed obtained by the relative speed change obtaining means as clearance information. Can be.

The change in relative speed when the following vehicle approaches a predetermined point of the vehicle depends on the distance between the following vehicle and the vehicle in the lateral direction of the vehicle. Therefore, the change in the relative speed is used as clearance information corresponding to the distance between the following vehicle and the vehicle in the vehicle lateral direction. In the vehicle periphery monitoring device, the distance between the vehicle and the following vehicle to be compared with the distance threshold is measured, and based on the change in the distance, the relative speed and further the change can be obtained.

[0015] The predetermined point of the vehicle can be considered as an installation position of a radar sensor for detecting a reflected wave of the radar wave reflected by the following vehicle when the vehicle behind is monitored by radar. Normally, in a vehicle, the mirror angle for confirming the rear is changed according to the position where the driver sits. From the viewpoint that the following vehicle can be reliably monitored even in the blind spot area that changes when the mirror angle is changed in this manner, the present invention provides the above-described aspect. Each of the vehicle periphery monitoring devices is further configured to include a monitoring range changing unit that changes the monitoring range so as to include the blind spot area of the mirror in the changed viewing range when the viewing range of the mirror is changed. be able to.

Further, from the viewpoint that appropriate information regarding the presence of a following vehicle can be provided to a driver according to the presence or absence of a lane change of the vehicle, the present invention provides a vehicle according to the present invention. In the periphery monitoring device, further, a positional relationship detecting means for detecting a relative positional relationship between the preceding vehicle traveling in the same lane as the vehicle and the vehicle, and a relative position detected by the positional relationship detecting means. A lane change prediction unit that performs a prediction determination as to whether or not the vehicle changes to an adjacent lane based on the relationship; and if it is determined that a subsequent vehicle exists in the blind spot area, the lane change prediction unit An information providing unit that provides different information to the driver according to the determination result can be provided.

In the current running state (speed, acceleration, etc.) of the vehicle, if it is predicted that the vehicle will catch up with the preceding vehicle, the driver usually changes lanes. Whether or not to catch up with the preceding vehicle can be predicted based on the relative positional relationship between the vehicle and the preceding vehicle. When it is determined that the following vehicle is present in the blind spot area, when the prediction determination that the lane change is to be made based on the relative positional relationship with the preceding vehicle is made, Different information is provided to the driver when the prediction is determined not to be made.

In such a vehicle periphery monitoring device, even when a following vehicle exists in the blind spot area, a more urgent warning or the like is issued when the positional relationship with the preceding vehicle changes the lane. The information can be provided to the driver, while in such situations, the driver can simply be informed of the presence of the following vehicle. The relative positional relationship between the vehicle and the preceding vehicle is information on the relative position of the vehicle, and includes a relative position (inter-vehicle distance) itself, a change in relative position (relative speed), and a change in relative speed (relative acceleration). ).

The information provided to the driver when the positional relationship with the preceding vehicle changes the lane includes an alarm sound, an alarm message, and an alarm from the viewpoint of avoiding the driver's lane change driving operation. It is preferable that the information is such that the driver can reliably recognize the lighting of the indicator lamp, the vibration of the seat, and the like. In addition, the information provided to the driver when the positional relationship with the preceding vehicle is not in a situation in which the lane is changed is obstructive to the driver from the viewpoint of minimizing the driver's inconvenience as much as possible. It is preferable that the information does not become unpleasant, harsh, or uncomfortable.

In order to solve the above problems of the present invention, further,
According to the present invention, as described in claim 5, a predetermined area including a blind spot area of a mirror having a rear peripheral portion of the vehicle as a visible range is set as a monitoring range, and a distance to a following vehicle in the monitoring range is measured. When the measured range becomes equal to or less than a distance threshold that is a reference value, in a vehicle periphery monitoring device that determines that a following vehicle is present in the blind spot area, when the visible range of the mirror is changed, the change is performed. It is configured to include a monitoring range changing unit that changes the monitoring range so as to include the blind spot area of the mirror in the later visible range.

In such a vehicle periphery monitoring device, since the blind spot area is changed together with the change in the visible range of the mirror, it is not necessary to predict the change in the visible range of the mirror and set the monitoring area in advance. Still further, in order to solve the above-mentioned problems of the present invention, the present invention provides, as described in claim 6,
A predetermined area including the blind spot area of the mirror having the rear peripheral portion of the vehicle as a visible range is set as a monitoring range, and a distance to a subsequent vehicle within the monitoring range is measured. A vehicle surroundings monitoring device that determines that a following vehicle is present in the blind spot area when the vehicle is in the same lane as the vehicle and detects a relative positional relationship between the preceding vehicle and the vehicle. Detecting means; lane change predicting means for making a prediction determination as to whether or not the vehicle will change to an adjacent lane based on the relative positional relationship detected by the positional relationship detecting means; When it is determined that there is a vehicle, information providing means for providing different information to the driver according to the determination result of the lane change prediction means is provided.

In such a vehicle periphery monitoring device, as described above, whether the vehicle will catch up with the preceding vehicle can be predicted based on the relative positional relationship between the vehicle and the preceding vehicle. Therefore, when it is predicted that a lane change will be made based on such a relative positional relationship, if it is determined that the following vehicle is present in the blind spot area, information that can be reliably recognized is provided to the driver. If it is not predicted that a lane change will be made, if it is determined that the following vehicle is present in the blind spot area, information is provided to the driver so that the driver does not feel as annoying as possible. Different information is provided to the driver.

[0023]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings. In the vehicle periphery monitoring device according to one embodiment of the present invention, the distance to another vehicle traveling behind the vehicle is measured by radar, and the vehicle side is determined based on whether the measured distance is equal to or less than a distance threshold Rth. It is determined whether or not another vehicle exists in the rear blind spot area Ed. And this distance threshold Rth
Is determined, for example, as follows.

The blind spot area Ed of the driver behind the vehicle Co, which cannot be visually recognized by the door mirror, is monitored using a radar. For example, as shown in FIG.
Is defined as the blind spot entry rate αα = B / A. Here, A is the lateral length of the maximum projection surface of the vehicle C1 by the radar beam irradiated to the blind spot area ED, and B is the lateral length of the actual projection surface of the vehicle C1 by the radar beam. . The later the blind spot entry rate α is, the more difficult it is for the driver to visually recognize the door mirror.

The own vehicle Co and the following vehicle C as shown in FIG.
1, the vehicle Co in the vehicle lateral direction X
When the distance Xc (hereinafter, referred to as clearance) between the rear vehicle C1 and the rear vehicle C1 is constant, the blind spot entry rate α increases as the following vehicle C1 approaches the host vehicle Co. The blind spot entry rate α increases as the clearance Xc of the following vehicle C1 increases. Therefore, the blind spot entry rate α that is equal to or more than a certain value (for example, 70% or more) that is difficult for the driver to visually recognize.
In order to detect the following vehicle as early as possible, the distance threshold Rth, which is a reference for determining whether or not another vehicle exists in the blind spot area ED, is changed according to the clearance Xc.

That is, as shown in FIG.
When c is small, the distance threshold Rth is reduced, and when the clearance Xc is large, the distance threshold Rth is increased. By doing this,
For the following vehicle C11 traveling at the position of the relatively small clearance Xc1, the relatively small distance threshold Rth
1 is used as a reference to determine whether or not the vehicle is in the blind spot area ED. Therefore, in a state where the blind spot entry rate α that is relatively easy for the driver to visually recognize with the door mirror is small, the following vehicle C11 enters the blind spot area ED. However, it can be determined that the vehicle is present in the blind spot area ED in a state where the blind spot entry rate α is equal to or more than a certain value. Further, for the following vehicle C12 traveling at the position of the relatively large clearance Xc2,
Since it is determined based on the relatively large distance threshold Rth2 whether or not the vehicle is in the blind spot area ED, it is possible to determine the entry into the blind spot area ED relatively early.

Specifically, as a result of the simulation, for example, as shown in FIG. 4, each distance threshold Rth1
, Rth2, Rth3 (Rth1 <Rth2 <Rth3), the relations Q1, Q2, Q3 between the clearance Xc and the blind spot entry rate α when it is determined that the following vehicle exists in the blind spot area ED are obtained. From such a relationship, the distance threshold according to the clearance Xc can be determined so that the blind spot entry rate α is always maintained at a high value (see the thick line portions in the curves Q1, Q2, and Q3).
For example, the relationship between the clearance Xc and the distance threshold Rth is determined as shown in FIG.

By the way, as shown in FIG.
When the succeeding vehicle C1 is traveling at a constant relative speed Vr in the lane adjacent to the lane in which the vehicle is traveling, the approach speed V (= Vr · cos θ) measured by the radar of the own vehicle Co becomes the following vehicle C1. Changes in accordance with the relative position of the vehicle with the vehicle Co. That is, the approaching speed V1 of the following vehicle C1 (P1) located far (P1) from the host vehicle Co is higher than the approaching speed V2 of the following vehicle C1 (P2) located near (P2) near the host vehicle C0. .

Further, the angle at which the radar sensor of the host vehicle Co desires the following vehicle C1 (hereinafter referred to as the aspect angle) varies depending on the clearance Xc. With the clearance Xc. The relationship between the distance measured by the radar and the approaching speed of the following vehicle is, for example, as shown in FIG.
It changes according to the clearance Xc of the following vehicle.

In a large target such as an automobile, a representative point (reflection representative point) at which a radio wave (eg, a microwave) from a radar is reflected changes depending on an aspect angle. If you look at
Since the aspect angle is limited to a certain range, the change of the reflection representative point at the target vehicle is small. That is, regarding a certain measurement distance range, it can be considered that the distance is measured based on a reflected wave from a certain point of the target vehicle. Therefore, in the characteristics shown in FIG. 7, in a certain measurement distance range (for example, between 4 meters and 5 meters), the change in the approach speed is measured under substantially the same conditions.

From the results shown in FIG. 7, for example, when the measurement distance range is 4 to 5 meters, the relationship between the clearance Xc of the following vehicle C1 and the rate of change of the approach speed is shown in FIG. 8, for example. Become like As described above, the change rate of the approach speed increases as the clearance Xc increases. By obtaining such characteristics for each measurement distance range, the relationship between the clearance Xc and the change rate of the approach speed is widened. It can be obtained over a measurement distance range.

The relationship between the clearance Xc and the rate of change of the approaching speed and the clearance Xc as shown in FIG.
By measuring the rate of change of the approaching speed of the following vehicle using the relationship between the threshold value and the distance threshold Rth, the optimum distance threshold Rth serving as a reference for determining whether or not the following vehicle exists in the blind spot area is determined. Can be specified.

In the vehicle periphery monitoring apparatus according to one embodiment of the present invention, as described above, the optimum distance threshold Rth is obtained by measuring the change rate of the approaching speed of the following vehicle.
Is determined, and whether or not the following vehicle has entered the blind spot area is determined using the distance threshold. Hereinafter, a vehicle periphery monitoring device according to an embodiment of the present invention will be specifically described.

FIG. 9 shows the relationship between a vehicle Co equipped with a vehicle periphery monitoring device and a following vehicle C1 traveling in a lane adjacent to the lane in which the vehicle Co travels. Vehicle Co
Is the FR radar sensor 12 provided near the right side mirror, and the FL is provided near the left side mirror.
Radar sensor 14, RR provided at right rear of vehicle
The radar sensor 16 and the R provided at the rear of the left vehicle body
It has an L radar sensor 18. The FR radar sensor 12 has a monitoring area ED1 including a blind area where the driver cannot visually recognize the door mirror on the right side, and the FL radar sensor 14 has a monitoring area ED2 including a blind area where the driver cannot visually recognize the door mirror on the left side. have. Also, RR
The radar sensor 16 has a monitoring area ED3 that is symmetrical with the monitoring area ED1 of the FR radar sensor 12,
The L radar sensor 18 has a monitoring area ED4 that is symmetrical with the monitoring area ED2 of the FL radar sensor 14.

A front surveillance radar 30 is installed in front of the vehicle Co, and a CCD camera 32 that shoots a white line that is a boundary of a lane is installed on the roof. The CCD camera 32 can be installed near a trunk or near a high-mount stop lamp so as to photograph a white line behind the vehicle. The vehicle periphery monitoring device mounted on the vehicle Co is configured as shown in FIG. In FIG. 10, detection signals from the above-described radar sensors 12, 14, 16, and 18 are sequentially supplied to an analog-to-digital converter 22 via a multiplexer 20, and the respective detection signals are supplied to the control unit 10 as digital signals. Have been.

The vehicle periphery monitoring device includes a mirror position detector 24, a mirror position read / store switch 26, and a seat position sensor 28. The mirror position detector 24 detects the angle of each door mirror. The mirror position read / store switch 26 has an operation switch for reading the angle (position) of each door mirror from a memory in the control unit 10 and an operation switch for storing the angle of each door mirror in the memory. The seed position sensor 28 detects the position of the driver's seat.
A detection signal from the mirror detector 24, an operation signal from the mirror position read / store switch 26, and a detection signal from the seat position sensor 28 are supplied to the control unit 10.

As described above, the detection signal from the forward monitoring radar 30 installed in the vehicle Co and the CCD camera 32
Are also supplied to the control unit 10. The control unit 10 has a non-volatile memory, which stores information on the angle of each door mirror as described above, and the seat position of the driver's seat and the optimum angle of each door mirror as described later. A table indicating the relationship is stored, a table indicating the relationship between the change rate of the approaching speed of the following vehicle C1 and the distance threshold Rth (see FIGS. 5 and 8), and various constants are stored. The control unit 10 performs a vehicle monitoring process, and as a result, outputs a control signal to the sensor beam direction adjusting mechanism 40 for adjusting the beam direction of each laser sensor and an alarm signal to the alarm output device 50.

The above-described vehicle monitoring process is executed in accordance with the procedures shown in FIGS. 11, 14 and 15. First, FIG.
Is an initial setting process for adjusting the monitoring area, that is, the direction of the beam of the radar sensor, according to the angle of the door mirror. Note that the initial installation process shown in FIG. 11 is a process for the radar sensor corresponding to the door mirror on one side. If the radar sensor corresponding to the door mirror on both sides needs to be adjusted, the initial setting process is performed on the radar sensor on both sides. This is executed for each of 12 and 14.

In FIG. 11, when the initialization process is started (S010), it is determined whether or not the operation switch for reading the mirror position in the mirror position read / store switch 26 has been operated (S02).
0). When the driver operates the operation switch to set the door mirror to the previously registered angle, the angle of the door mirror stored in the memory is read out, and the door mirror adjusting mechanism (not shown) is set to the angle. ) Is supplied with a control signal (S030).

After the driver adjusts the angle of the door mirror, it is determined whether or not the operation switch for storing the mirror position in the mirror position read / store switch 26 has been operated (S040). Here, when the driver operates the operation switch, the angle θa (position) of the door mirror detected by the mirror position detector 24 and the seat position La detected by the seat position sensor 28 at that time are stored in the memory. Is performed (S050).

If the mirror position read / store switch 26 is not operated to adjust the door mirror to the registered mirror position or to newly register the position of the door mirror and the seat position, the mirror position is not changed. The reading and adjustment (S030) and the processing of storing the mirror position and the sheet position (S050) are not executed. In the memory of the control unit 10, for example, the relationship Q between the seat position La of the driver's seat and the optimum mirror angle θa as shown in FIG.
Stores a table indicating a. This is because the door mirror is adjusted to an angle (optimum angle) at which the rear optimal range Ao1 (for example, a range of 18 °) can be visually recognized when the viewpoint is at the seat position L as shown in FIG. Has become. In addition, the radar sensors 12 and 14 provided in the vicinity of each door mirror have the monitoring area E so as to include a blind spot area that cannot be visually recognized by the door mirror adjusted to the optimum angle.
The center direction of the beam is adjusted so that D1 and ED3 are formed.

When the angle of the door mirror is adjusted as described above, the angle θa of the door mirror detected by the mirror position detector 24 is obtained. Further, the optimum mirror angle θ (L) corresponding to the current sheet position La detected by the sheet position sensor 28 is obtained from the table described above. Then, a difference Δθm (= θ (L) −θa) between the detected mirror angle θa and the optimum mirror angle θ (L) corresponding to the sheet position La is calculated (S06).
0).

Then, a control signal is supplied to the sensor beam direction adjusting mechanism 40 so that the center direction of the beam of the radar sensor is shifted by the angle difference Δθm (S07).
0). As a result, as shown in FIG. 13, from the center direction Bo1 of the beam of the radar sensor set corresponding to the optimum viewing range A01 of the door mirror, a blind spot area corresponding to the adjusted viewing range Ao2 of the door mirror is included. The center direction Bo2 of the beam of the radar sensor for forming the monitoring area
Is corrected to As described above, since the center direction of the beam of the radar sensor is corrected, it is possible to prevent the visibility range of the door mirror from overlapping with the monitoring area of the radar sensor due to the door mirror angle adjustment.

The initial setting process for adjusting the center direction of the beam of the radar sensor as described above is completed (S08).
0), while the vehicle Co is traveling, the control unit 10
Executes an obstacle (following vehicle) recognition process according to the procedure shown in FIG. Now, it is assumed that the relationship between the vehicle Co equipped with the vehicle periphery monitoring device and the following vehicle C1 is as shown in FIG. In such a situation, the control unit 10 calculates the distance R to the rear vehicle C1 based on the reflected wave from the rear object (rear vehicle C1) detected by the FR radar sensor 12. In this state, as shown in FIG. 14, when the obstacle recognition process is started (S110), a flag Fexist indicating whether or not the following vehicle exists in the blind spot area is initially reset (fex).
ist = 0) (S115).

Then, the measured distance R to the following vehicle C1
Is 10 meters, for example, the approach speed V (R = 10 m) of the following vehicle C1 to the vehicle Co is calculated based on the detection result of the FR radar sensor 12 (S120). The approaching distance of 10 meters is predetermined as a distance within the monitoring area ED1 of the FR radar sensor 12 that can be considered to be sufficiently far from the vehicle Co.
Therefore, this approach speed V (R = 10 m) can be regarded as the relative running speed Vr of the following vehicle C1 (see FIG. 6).

Thereafter, the measured distance R to the following vehicle C1
Are, for example, 7 meters and 5 meters, respectively, the approach speeds V (R = 7 m) and V (R = 5 m) of the following vehicle C1 based on the detection results of the FR radar sensor 12, respectively.
Is calculated. Then, using these approach speeds, the change rate β of the approach speed is calculated in accordance with β = {V (R = 7m) −V (R = 5m)} / V (R = 7m) (S130).

As described above, the change rate β corresponds to the clearance of the following vehicle C1 with respect to the vehicle Co (see FIG. 8). That is, the position of the clearance corresponding to the change rate β of the approach speed is determined by the following vehicle C1.
Is approaching. Next, the distance Ra is calculated according to the following equation (S140). Ra = (R / V) .V (R = 10 m) In the above equation, R is a measured distance, and V is a measured approach speed.

Here, V (R = 10 m) is the approach speed of the following vehicle C1 at a sufficiently long distance as described above, and can be regarded as the relative running speed Vr of the following vehicle C1. The measured approach speed V can be expressed as V = Vr · cos θ as shown in FIG. Therefore, the distance Ra is approximated as Ra と R / cos θ. When the distance Ra is fixed to a constant value Rath,
The point p (R, θ) is a point on the semicircle of the diameter Rath with the FR radar sensor 12 at one end, as shown by the two-dot chain line in FIG. By setting this Rath appropriately, the semicircular area (hereinafter referred to as a detection area) can be set as an area where the blind area of the door mirror and the monitoring area ED1 of the FR radar sensor 12 overlap. This R
ath is set to, for example, 4 meters.

To determine whether or not the following vehicle C1 has entered this detection area, the distance Ra calculated as described above is used.
Is smaller than the reference value Rath (S
150). When the following vehicle C1 traveling in the adjacent lane approaches the vehicle Co, and the distance Ra calculated as described above becomes smaller than the reference value Rath, the following vehicle C1 enters a blind spot area where the driver cannot visually recognize it with the door mirror. Therefore, the following processing is continuously executed.

First, the distance threshold Rth corresponding to the change rate β of the approach speed calculated as described above is read from the table (see FIGS. 5 and 8) stored in the memory of the control unit 10 (S160). This distance threshold Rth (for example, Rth1, Rth2, Rth shown in FIG. 5)
th3), as shown in FIG.
And the following vehicle C1.

Then, it is determined whether or not the distance R to the following vehicle C1 measured by the FR radar sensor 12 is equal to or less than the distance threshold Rth set in this way (S170). This measured distance R is the distance threshold R
If it has not reached th, it is determined that the driver can still see the following vehicle C1 through the door mirror, and the flag Fex
ist is reset (Fexist = 0) (S1
90). Then, the distance Ra is calculated again (S1).
92) In order to determine whether or not the following vehicle C1 has exited the detection area, the calculated distance Ra is set to the reference value Rat.
It is determined whether it is smaller than h (S194).

If the calculated distance Ra is smaller than the reference value Rath, the above process is repeated assuming that the following vehicle C1 still exists in the detection area (S170, S170).
190, S192, S194). In the course of repeating such processing, if it is determined that the measured distance R to the following vehicle C1 is equal to or less than the distance threshold Rth (S17).
0, YES), it is assumed that many portions of the following vehicle C1 are in the blind spot area (the entrance rate α is large. FIGS. 2 to 4).
), The flag Fexist is set (Fexist =
1) (S180). In this state, the distance Ra is calculated (S192), whether or not the distance Ra is smaller than the reference value Rath (S194), and whether or not the measured distance R has reached the distance threshold Rth (S170). The flag Fexist is set based on the determination result (S18).
0) is repeated.

In the course of such processing, the following vehicle C1 leaves the detection area, and the distance Ra becomes equal to the reference value Rath.
If it is determined that the value is larger than the predetermined value (S194, NO), the flag Fexist is reset (S196), and the obstacle recognition process ends (S200). Thereafter, each time a following vehicle in an adjacent lane enters the monitoring area ED1 of the FR radar sensor 12, the control unit 10 executes the above-described obstacle recognition processing.

As described above, while the vehicle Co is traveling, the control unit 10 performs an obstacle recognition process and, for example, performs the operation shown in FIG.
The alarm output process is executed according to the procedure shown in FIG.
In FIG. 15, when the alarm output process is started (S
210), as described above, the measured distance R of the following vehicle C1
Is set or reset depending on whether or not the vehicle has reached the distance threshold Rth, that is, whether or not the following vehicle C1 is traveling in an area where it is difficult to visually recognize the door mirror.
It is determined whether or not ist is set (S22).
0). If the flag Fexist is not set (Fexsist = 0), it is determined that there is no following vehicle in the blind spot area of the door mirror, and this alarm output processing is ended (S260).

On the other hand, when the flag Fexist is set, it is further determined whether or not the direction indicator for changing lanes to the adjacent lane on the FR radar sensor 12 side detecting the following vehicle C1 has been operated. (S222), CC
Based on the white line image of the lane boundary obtained from the D camera 32, it is determined whether or not the vehicle Co has protruded into the adjacent lane on the FR radar line 12 side (S225). Each determination is made as to whether or not the relative positional relationship of (1) has a predetermined condition (S230). Determination of relative positional relationship with the preceding vehicle (S23)
0), the inter-vehicle distance with the preceding vehicle is a predetermined distance Rfr.
It is defined as a predetermined condition to be a criterion that the vehicle speed is smaller than that or the change in the inter-vehicle distance is larger than a predetermined change dRfr. Such a condition is a condition under which it is considered that the vehicle Co approaches the preceding vehicle and the necessity of changing lanes has arisen.

In each of the above determination processes, the turn signal is not operated (NO in S222), and the vehicle Co does not protrude into the adjacent lane (N in S225).
O) and when it is determined that the relative positional relationship with the preceding vehicle does not satisfy the predetermined condition (N in S230)
O), the control unit 10 supplies information for informing the driver of the presence of the following vehicle to the alarm output device 50 based on the state of the flag Fexist. Alarm output device 50
Performs processing such as image display and audio output. In this case, in the image display, for example, a mark that does not cause annoyance to the driver is displayed, and in the audio output, a sound having a frequency that does not cause annoyance is output for a short time.

By the image display and the sound output of the alarm output device 50, the driver can know that the following vehicle exists in the blind spot area of the door mirror on the right side of the vehicle Co. Therefore, the driver can continue the driving operation of the vehicle Co while grasping the situation where the following vehicle is traveling in the adjacent lane. On the other hand, in each of the above determination processes, it is determined that the operation of the direction indicator has been performed (S222).
, YES), it is determined that the vehicle Co has run off the adjacent lane (YES in S225), and it is determined that the relative positional relationship with the vehicle ahead satisfies a predetermined condition (S230).
If one of the above is performed, the control unit 1
0 supplies alarm information to the alarm output device 50. The alarm output device 50 outputs an alarm sound, an alarm display, and an alarm such as vibrating a driver seat. In this case, it is dangerous to change lanes in the presence of a following vehicle, so that the driver can intermittently emit an audible alarm to the driver's ear so that the driver can recognize the lane. The alarm display mark blinks or the driver's seat vibrates intermittently.

By the alarm output process of the alarm device 50, the driver who attempts to change lanes to the adjacent lane can be alerted and the lane changing operation can be discouraged. In the above example, the FR radar sensor 1 is used for the blind spot area of the door mirror on the right side of the vehicle Co.
Although the processing is performed based on the detection information in step 2, similar processing is performed based on the detection information from the FL radar sensor 14 for the following vehicle in the adjacent lane to the left of the vehicle Co. Further, other RR radar sensors 16 and RL
The radar sensor 18 further includes a monitoring area ED
3. Used for monitoring obstacles in ED4.

Further, the FR radar sensor 12 and F
Instead of the L radar sensor 14, for example, as shown in FIG. 16, radar sensors 13 and 15 for monitoring the side rear blind spot area of the vehicle Co can be provided at the rear end of the vehicle Co. In the above example, the clearance between the vehicle Co and the following vehicle C1 is estimated from the change rate β of the approaching speed. However, the present invention is not limited to this, and other sensors such as radar installed on the vehicle Co may be used. It can also be measured directly based on the information. When the clearance is estimated from the change rate β of the approach speed as in the above example, such special sensors are not required, and the cost can be reduced.

In the above example, the processing is performed using each of the FR radar sensors 12 (FL radar sensors 14) and their detection information.
The process at 130 corresponds to the clearance information obtaining means (relative speed change obtaining means), and the distance threshold Rth is determined based on the information obtained in the processing (step S).
The processing at 160 corresponds to the reference value setting means.

The initial setting process shown in FIG. 11 corresponds to the monitoring range changing means. Further, the process of detecting the inter-vehicle distance to the preceding vehicle and a change in the inter-vehicle distance using the forward monitoring radar 30 (part of the process in step S230 shown in FIG. 15) corresponds to the positional relationship detecting means.
1 corresponds to the lane change prediction means.
The alarm output device 50 that operates based on the processing in steps S240 and S250 shown in FIG. 5 corresponds to the information providing unit.

[0062]

As described above, according to the present invention as set forth in claims 1 to 4, a larger portion of the rear vehicle enters the blind spot area of the mirror having the rear peripheral portion of the vehicle as a visible range. Then, when it is difficult for the driver to visually recognize the following vehicle with the mirror, it is determined that the following vehicle exists in the blind spot area.

According to the fifth aspect of the present invention,
Even if the visible range of the mirror is always changed, the monitoring area is always changed to include the blind spot area of the mirror, so that it is not necessary to set a wider monitoring area in consideration of the change in the visible range of the mirror. . Furthermore, according to the present invention as set forth in claim 6, in a situation where it is determined that a following vehicle exists in the blind spot area of the mirror, when the vehicle is predicted to change lanes to an adjacent lane, The information provided is different. Therefore, when a lane change is predicted, a more urgent warning is provided, and otherwise, information that does not cause driver discomfort, harshness, or discomfort is provided. Information can be provided to the driver.

As described above, according to the invention described in each claim, a vehicle traveling in the blind spot area behind the vehicle is monitored, and information is provided to the driver according to the monitoring result. In such a vehicle periphery monitoring device, it is possible to always provide useful information to the driver.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a situation of a following vehicle entering a rear side blind spot area of the vehicle.

FIG. 2 is a diagram illustrating a blind spot entry rate of a following vehicle entering a rear side blind spot area of the vehicle.

FIG. 3 is a diagram showing a general relationship between a clearance of a following vehicle entering a rear side blind spot area of the vehicle and a blind spot entry rate.

FIG. 4 is a diagram showing a specific relationship between a clearance of a following vehicle entering a rear side blind spot area of the vehicle and a blind spot entry rate.

FIG. 5 is a diagram illustrating a relationship between a clearance and a distance threshold.

FIG. 6 is a diagram illustrating a relationship between an approach speed and a relative running speed of a vehicle and a following vehicle.

FIG. 7 is a diagram showing a relationship between a measured distance of a following vehicle and a change in approach speed.

FIG. 8 is a diagram illustrating a relationship between a clearance and an approach speed change rate.

FIG. 9 is a diagram showing a positional relationship between a vehicle equipped with the vehicle periphery monitoring device according to one embodiment of the present invention and a following vehicle traveling in an adjacent lane.

FIG. 10 is a block diagram illustrating a configuration example of a vehicle periphery monitoring device according to an embodiment of the present invention.

FIG. 11 is a flowchart illustrating a procedure of an initial setting process.

FIG. 12 is a diagram showing a relationship between a driver's seat position and an optimum angle of a door mirror.

FIG. 13 is a diagram showing a change in the monitoring area of the radar sensor corresponding to a change in the angle of the door mirror.

FIG. 14 is a flowchart illustrating a procedure of an obstacle recognition process.

FIG. 15 is a flowchart illustrating a procedure of an alarm output process.

FIG. 16 is a diagram showing another installation example of the radar sensor.

[Explanation of symbols]

 Reference Signs List 10 control unit 12 FR radar sensor 14 FL radar sensor 16 RR radar sensor 18 RL radar sensor 20 Multiplexer (MPX) 22 analog-digital converter 24 mirror position detector 26 mirror position read / store switch 28 seat position sensor 30 forward monitoring radar 32 CCD camera 40 Sensor beam direction adjusting mechanism 50 Alarm output device

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (reference) B60R 21/00 626D 626A 628E G01S 17/88 A

Claims (6)

[Claims] A monitoring area is defined as a predetermined area including a blind spot area of a mirror having a visibility area in a rear peripheral portion of a vehicle, and a distance to a subsequent vehicle within the monitoring area is measured, and the measured distance is a reference value. In a vehicle periphery monitoring device configured to determine that a following vehicle is present in the blind spot area when the threshold value or less is obtained, clearance information corresponding to a distance between the vehicle and the following vehicle in the vehicle lateral direction is acquired. A vehicle comprising: clearance information acquisition means; and reference value setting means for setting a distance threshold based on the acquired clearance information, such that the distance threshold value decreases as the distance between the vehicle and the following vehicle in the vehicle lateral direction decreases. Perimeter monitoring device. 2. A vehicle periphery monitoring device according to claim 1, wherein said clearance information acquiring means acquires relative speed change acquiring means for acquiring a change in relative speed when a following vehicle approaches a predetermined point of the vehicle. A vehicle periphery monitoring device having a relative speed change obtained by the relative speed change obtaining means as clearance information. 3. The vehicle periphery monitoring device according to claim 1, further comprising, when the view range of the mirror is changed, changing the monitor range to include the blind spot area of the mirror in the view range after the change. A vehicle periphery monitoring device provided with a monitoring range changing unit that performs monitoring. 4. A vehicle periphery monitoring device according to claim 1, further comprising: a positional relationship detecting means for detecting a relative positional relationship between a preceding vehicle traveling in the same lane as the vehicle and the vehicle. Lane change prediction means for predicting whether or not the vehicle changes to an adjacent lane based on the relative positional relationship detected by the positional relation detection means; and a following vehicle exists in the blind spot area. An information providing unit that provides different information to the driver according to the determination result of the lane change prediction unit when the determination is made. 5. A monitoring area is defined as a predetermined area including a blind spot area of a mirror having a visual recognition area in a rear peripheral portion of the vehicle, and a distance to a following vehicle within the monitoring area is measured, and the measured distance becomes a reference value. In a vehicle periphery monitoring device configured to determine that a following vehicle is present in the blind spot area when the threshold becomes equal to or less than the threshold, when the view range of the mirror is changed, the blind spot area of the mirror in the changed view range is changed. A vehicle surroundings monitoring device comprising a monitoring range changing means for changing a monitoring range so as to include: 6. A monitoring area is defined as a predetermined area including a blind spot area of a mirror having a rear peripheral area of the vehicle as a visible area, and a distance to a following vehicle within the monitoring area is measured, and the measured distance becomes a reference value. When the vehicle is below the threshold, the vehicle surroundings monitoring device is configured to determine that a following vehicle exists in the blind spot area, and determines a relative positional relationship between a preceding vehicle traveling in the same lane as the vehicle and the vehicle. A positional relationship detecting means for detecting, a lane change predicting means for making a prediction determination as to whether or not the vehicle changes to an adjacent lane based on the relative positional relationship detected by the positional relationship detecting means; A vehicle surroundings provided with information providing means for providing different information to the driver according to the determination result by the lane change prediction means when it is determined that a following vehicle exists in the area; Visual apparatus.