JPH085736A - Proximity warning device for vehicle - Google Patents

Abstract

PURPOSE:To suppress erroneous alarms and unnecessary primary alarms (for calling driver's attention) and to prevent the occurrence of am alarming delay when a vehicle excessively approaches a preceding vehicle by providing a means which recognizes a measurement impossible state and another means which recognizes that the distance between the two vehicles remarkably changes and setting alarming distance holding time and alarm suppressing time in accordance with the state. CONSTITUTION:After radar equipment 21 measures the distance L to a preceding vehicle from its own vehicle, an information processing circuit 25 calculates the relative speed Vr between the two vehicles when the distance L can be measured, does not change remarkably, and can be continuously detected by, for example, four values only. Then the circuit 25 calculates the alarming distance D0 which becomes a reference distance for issuing an alarm. The distance D0 is divided into a primary alarming distance D1 for awakening the attention of the driver of its own vehicle and secondary alarming distance D2 for emergency case and a primary alarm is issued when D2<=<D1. When L<D2, a secondary alarm is issued. When the distance L cannot be measured or remarkably changes, the circuit 2 holds the distance D0 immediately before recognition for a fixed period of time and actuates an alarm generator 27 after discriminating the need of issuing an alarm by comparing the distance D0 with a newly measured distance L.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an approach warning device for a vehicle, which detects a distance between a host vehicle and a preceding vehicle and gives an alarm to a driver when the vehicle approaches too much.

[0002]

2. Description of the Related Art As a conventional approach warning device for a vehicle,
“Automotive Technology” Vol.43, No.2,1989, p.
p65-73 ",""Special Issue on Automotive Engineering" 1992-
1993 Technology of the Year, pp32-
57 "and other publications, and
For example, the one described in Japanese Utility Model Laid-Open No. 1-152228 is available. In the above device, an electromagnetic wave (for example, a laser beam) is emitted to the front of the vehicle, a reflected wave of the electromagnetic wave is received, and the distance R to the reflector is detected from the propagation delay time from output to reception. Then, the alarm distance Rs is calculated based on the relative speed detected from the change of the distance R, the alarm distance Rs is compared with the measured distance R, and the actual distance R is calculated.
Is shorter than the warning distance Rs, the driver is warned that it is too close. The above-mentioned warning distance corresponds to the minimum distance that can be safely stopped or avoided with a margin, and if it is less than that, it will be in an excessively close state. The above warning distance Rs is, for example, the following (Equation 1)
Calculated by the formula.

[0003]

[Equation 1]

However, Va: vehicle speed of the own vehicle Td: idle running time α: deceleration d / dt R: relative speed between the own vehicle and the preceding vehicle Note that the idle running time Td is judged to be excessive approach by the driver. This is the time from when the deceleration or braking actually starts to be performed. In addition, if the driver is driving with a safe distance between them in that situation, or if the driver keeps approaching until just before overtaking, etc. Keeps ringing, which hinders comfortable driving, and reduces the driver's attention to the warning due to too much warning, making it impossible to call attention to excessive approach, which is the original purpose of the warning. Will end up. Therefore, in the conventional preceding vehicle approach warning device, a second warning distance R ₀ shorter than the above warning distance Rs is set, and a primary warning is issued when the actual inter-vehicle distance R becomes equal to or less than the warning distance Rs. , The alarm is divided into two stages so that a secondary alarm is generated when the second alarm distance R ₀ or less, and in the first stage, a primary alarm signal for alerting is generated for a certain period of time and then stopped to generate an alarm. The instrument is designed so that it does not continue to ring, and the secondary emergency alarm is continuously generated in the second stage when no further approach is possible.

[0005]

Such a conventional approach warning device for a vehicle calculates a relative speed from distance data between the host vehicle and a predetermined target object, and calculates an alarm distance based on the relative speed and the host vehicle speed. are doing. Therefore, the value of the measured distance is such as when detecting the road surface in the vicinity by the posture change of the distance measuring device according to the movement of the vehicle or when the distance measuring device detects the distance to a structure or the like outside the road. In the case of a drastic change, the alarm distance changes significantly, which may cause an unnecessary false alarm. Further, when the preceding vehicle is out of the measurement field of view of the distance measuring device and the distance measurement cannot be performed, a new relative speed is not calculated until the distance data of the distance measuring device is collected by a predetermined number required for calculation. Therefore, there is a problem that the alarm distance is not set and the alarm is not issued even if an excessively close state occurs due to an interrupting vehicle or the like. Also,
In order to suppress the frequent occurrence of the primary alert for alerting, once the primary alert occurs, a certain time (for example, 10
In some cases (second to 25 seconds), the primary alarm may not be issued. However, if the primary alarm is simply suppressed for a certain period of time, the alarm will be generated again after the above certain period of time, even if the conditions such as the vehicle interval do not change, and the driver feels complicated. There was a problem that the reliability of the alarm might be lowered while holding it.

The present invention has been made in order to solve the problems of the prior art as described above, and an object thereof is to provide an approach warning device for a vehicle without false alarms or alarm delays.

[0007]

In order to achieve the above object, the present invention is constructed as described in the claims. That is, in the invention according to claim 1, it is recognized that the vehicle-to-vehicle distance measuring means mounted on the vehicle for measuring the distance between the own vehicle and the target object and the distance between the vehicle-to-vehicle distance measuring means cannot be measured. The distance between the host vehicle and the target object is determined by the unmeasurable recognition means, the distance change amount recognition means for recognizing that the distance measured by the inter-vehicle distance measurement means changes discontinuously and significantly. And a relative speed calculating means for calculating the relative speed between the own vehicle and the target object from the change in the distance between the own vehicle and the target object when recognizing that it can be measured and does not change significantly discontinuously. A vehicle speed detection means for detecting a vehicle speed, an alarm distance calculation means for calculating an alarm distance based on the vehicle speed and the relative speed, and an unmeasurable recognition means or a distance change recognition means, distance Time measurement means for measuring the elapsed time from the time when it was recognized that the measurement could not be made or the measured distance changed discontinuously and significantly, and while the above elapsed time was within the predetermined time, or Until the warning distance is calculated based on the relative speed calculated in step 1, the warning distance holding means holds the warning distance calculated by the warning distance calculating means, the distance between the own vehicle and the target, and the warning. An alarm generation determination unit that determines whether or not to issue the alarm based on the distance, and an alarm generation unit that issues an alarm according to the determination of the alarm generation determination unit. The above means correspond to, for example, the following parts in the embodiment of FIG. That is,
The inter-vehicle distance measuring means is the radar device 21, the own vehicle speed detecting means is the vehicle speed sensor 23, and the alarm generating means is the alarm generating device 27.
And the relative speed calculation means, the warning distance calculation means, the warning occurrence determination means, the measurement failure recognition means, the distance variation recognition means, the time measurement means, and the warning distance holding means. Equivalent to.

Next, the invention according to claim 2 is, as the alarm distance calculating means, a primary alarm distance corresponding to a primary alarm for alerting and a secondary alarm distance corresponding to a secondary alarm for emergency. And the alarm generation determination means is configured to determine whether to issue the primary alarm or the secondary alarm.

Next, the invention according to claim 3 relates to claim 1
Alternatively, in the approach warning device for a vehicle according to claim 2,
When the unmeasurable recognition means or the distance variation recognition means recognizes that the distance cannot be measured or the measured distance changes discontinuously, the time measurement means measures from the point of time of recognition. During the predetermined time, the inter-vehicle distance measured by the inter-vehicle distance measuring means is compared with the inter-vehicle distance immediately before the recognition, and when the difference is smaller than a predetermined value, the alarm occurrence determination means is notified. An inter-vehicle distance comparison means for transmitting an alarm suppression signal is added, and the alarm occurrence determination means suppresses the generation of the primary alarm when the alarm suppression signal is given after the alarm is issued. It is configured as follows. The above-mentioned inter-vehicle distance comparing means corresponds to, for example, a part of the information processing circuit 25 in the embodiment shown in FIG.

The invention described in claim 4 is the same as claim 3
In the vehicular approach warning device described in (1), the warning occurrence determination means is configured as follows. That is, when the warning distance calculation means newly calculates the primary warning distance and the secondary warning distance, and the inter-vehicle distance that is longer than the new primary warning distance by a predetermined value or more is measured, during the predetermined time period. Even if there is, the alarm suppression signal is configured to be invalid.

Further, the invention described in claim 5 is the same as claim 3
Alternatively, in the approach warning device for a vehicle according to claim 4,
The distance change amount recognizing means is for recognizing that a long distance is discontinuously measured, and the inter-vehicle distance comparing means is measured by the time measuring means from the time when the distance discontinuously changes long. During a predetermined time, the inter-vehicle distance measured by the inter-vehicle distance measuring means is compared with the inter-vehicle distance immediately before the above-mentioned distance changes discontinuously, and if the difference is smaller than a predetermined value, the alarm is issued. An alarm suppression signal is sent to the determination means, and the alarm generation determination means, when the alarm suppression signal is given after the alarm is issued,
It is configured to suppress the generation of the primary alarm.

The invention according to claim 6 is the same as claim 3
Alternatively, in the approach warning device for a vehicle according to claim 4,
The distance change amount recognizing means is for recognizing that a short distance is discontinuously measured, and the inter-vehicle distance comparing means is measured by the time measuring means from a time point when the distance discontinuously changes. During a predetermined time, the inter-vehicle distance measured by the inter-vehicle distance measuring means is compared with the inter-vehicle distance immediately before the above-mentioned distance changes discontinuously, and if the difference is smaller than a predetermined value, the alarm is issued. An alarm suppression signal is sent to the determination means, and the alarm generation determination means, when the alarm suppression signal is given after the alarm is issued,
It is configured to suppress the generation of the primary alarm.

The invention described in claim 7 is the same as claim 3
Alternatively, in the approach warning device for a vehicle according to claim 4,
The distance change amount recognizing means distinguishes between a case where a discontinuously long distance is measured, a case where a discontinuously short distance is measured, and a case where other distances are measured, and Time constant changing means for changing the length of the predetermined time in the time measuring means according to the recognition result is added, and the inter-vehicle distance comparing means, the time from the time when the distance changes discontinuously During the predetermined time measured by the measuring means, the inter-vehicle distance measured by the inter-vehicle distance measuring means is compared with the inter-vehicle distance immediately before the above distance changes discontinuously, and when the difference is smaller than the predetermined value. To send an alarm suppression signal to the alarm occurrence determination means, and the alarm occurrence determination means suppresses the generation of the primary alarm when the alarm suppression signal is given after the alarm is issued. Like One in which the. The time constant changing means corresponds to, for example, a part of the information processing circuit 25 in the embodiment shown in FIG.

[0014]

1 to 3 are functional block diagrams of the present invention. The operation of the present invention will be described below with reference to FIGS. Since the target objects on which the vehicle may collide on the road are equivalent to falling objects, leading vehicles, and stopped vehicles, all target objects will be described as vehicles in the following description. First, FIG. 1 shows claims 1 and 2.
It is a figure which shows the structure corresponding to. In FIG. 1, an inter-vehicle distance measuring means 1 corresponds to, for example, a radar device 21 in an embodiment shown in FIG. 4 described later, and a vehicle speed detecting means 3 is a vehicle speed sensor 2
3, the alarm generation means 11 corresponds to the alarm generation device 27, and the relative speed calculation means 5, the alarm distance calculation means 7, the alarm generation determination means 9, the immeasurable recognition means 13, the inter-vehicle distance change amount recognition means 15, The portions of the time measuring means 16 and the alarm distance holding means 17 correspond to the information processing circuit 25.

In FIG. 1, the inter-vehicle distance measuring means 1 first measures the inter-vehicle distance L between the host vehicle and the preceding vehicle. Next, the unmeasurable recognition means 13 recognizes whether or not the inter-vehicle distance L has been measured. For example, after radar output,
If the reflected wave can be received within a predetermined time (time required for the electromagnetic wave to make a round trip to the limit distance of the radar device, for example, 1 μsec), it is recognized that the measurement has been completed. When the distance can be measured, the inter-vehicle distance change amount recognizing unit 15 recognizes whether or not the inter-vehicle distance has changed discontinuously and greatly from the amount of change between the inter-vehicle distance measured last time and the inter-vehicle distance measured this time. To do. When a predetermined number (the number required for calculation, for example, four) of vehicle distances can be continuously detected without a large discontinuous change in vehicle distance, the relative speed calculation unit 5 detects the vehicle distance L per unit time. The relative speed Vr is calculated from the amount of change.
The measurement data of the inter-vehicle distance measuring means 1 is stored in a memory (not shown) so that it can be used for comparison calculation with subsequent data if necessary. Next, the alarm distance calculation means 7 calculates an alarm distance D ₀ which is a reference for issuing an alarm. Next, the warning occurrence determination means 9 compares the warning distance D ₀ with the inter-vehicle distance L, and outputs an alarm signal when the inter-vehicle distance L is shorter than the warning distance D ₀ . Then, the alarm generating means 11 generates an alarm in response to the alarm signal.

On the other hand, when the inter-vehicle distance L cannot be measured, or when the change amount of the inter-vehicle distance is discontinuously large, time is measured by the time measuring means 16 from the point of recognition thereof. Then, within a predetermined time (for example, about 2 seconds), the warning distance holding unit 17 holds the warning distance D ₀ immediately before the recognition time. Next, the alarm occurrence determination means 9 holds the above until the inter-vehicle distance can be measured again and the predetermined number of distance data are gathered and the alarm distance based on a new relative speed can be set during the above predetermined time. The warning distance and the measured inter-vehicle distance are compared, and the same judgment as above is made to judge whether or not the warning is to be issued. When a predetermined number of inter-vehicle distance data are gathered within the predetermined time and a new warning distance can be set, the judgment is made based on the new warning distance. After the lapse of the predetermined time, the alarm distance held by the alarm distance holding means 17 is erased, and a state of waiting for the generation of a new target object is set.
In addition, when the inter-vehicle distance L cannot be measured,
This is a case where after the electromagnetic wave is emitted from the radar device, no reflection is received within a predetermined time. The predetermined time in this case is, for example, 1 μsec, which corresponds to the time for which light travels 300 m. In the case of a radar device, since it is a round trip time, in the above example, when there is no object within 150 m,
It takes more than 1 μsec from the output to the reception, and measurement becomes impossible. For example, when the preceding vehicle accelerates and the inter-vehicle distance becomes large, or when the preceding vehicle deviates from the measurement field of view of the radar device due to a lane change or the like, measurement becomes impossible. Further, the criterion for determining that the amount of change in the inter-vehicle distance is discontinuously large is, for example, that the discontinuity is discontinuous when the difference between the previous distance data and the current distance data is ± 5 m or more. to decide. For example, the measured values are "... 30m, 29m, 31m, 6
When it changes like “2 m”, it is determined that “31 m, 62 m” is discontinuous. As described above, when the inter-vehicle distance L cannot be measured, there is a possibility that the preceding vehicle has deviated from the measurement visual field of the inter-vehicle distance measuring means 1 due to the lane change of the preceding vehicle, and the change amount of the inter-vehicle distance L. If the value is discontinuously large, it is possible that the target object has changed from the preceding vehicle to a structure outside the road, a road surface, or the like due to a change in the vehicle attitude. In such a case, if the usual alarm distance calculation is performed, there is a possibility that the abnormal value does not match the actual situation. However, in such a case, if the alarm is stopped at all in order to avoid generation of an unnecessary alarm, the alarm is issued even when an alarm is necessary, such as when the inter-vehicle distance L suddenly becomes small due to an interrupting vehicle or the like. It will not occur. Therefore, in the configuration of FIG. 1, the alarm distance immediately before is held for a predetermined time, and the alarm determination is performed based on the value. With this configuration, it is possible to promptly and properly issue an alarm even when the situation suddenly changes. Further, even if the above-mentioned warning distance is maintained within a predetermined time, if a predetermined number of inter-vehicle distance measurement data are available, a normal warning distance calculation is performed, and therefore the inter-vehicle distance with the preceding vehicle is actually calculated. If it changes,
The alarm judgment corresponding to it is performed.

Next, in the invention as set forth in claim 2, the alarm distance calculating means 7 is based on the own vehicle speed Va detected by the own vehicle speed detecting means 3 and the relative speed Vr, and is used as a primary alert signal. An alarm distance D ₁ and an emergency secondary alarm distance D ₂ (however, D ₂ <D ₁ , for details, refer to the mathematical formulas of D ₁ and D _{2 in} the examples described later) are calculated. Next, the alarm occurrence determination means 9 compares the two alarm distances D ₁ and D ₂ with the inter-vehicle distance L. If D ₂ ≦ L <D ₁ , a primary alarm, L <
In the case of D ₂ , the warning signal of the secondary warning is output. Then, the alarm generating means 11 generates a primary alarm or a secondary alarm according to the alarm signal. Since the primary alarm is a light alarm for alerting, it should be an intermittent or intermittent alarm, and the secondary alarm should be a continuous alarm. On the other hand, the distance L
Is not measured or the amount of change in the inter-vehicle distance is discontinuously large, the time is measured by the time measuring means 16 from the time of recognition thereof. Then, within a predetermined time (for example, about 2 seconds), the warning distance holding means 17 holds the warning distances D ₁ and D ₂ immediately before the recognition time. The other parts are the same as those described in claim 1. As described above, the warning is divided into two stages, the primary alert for alerting is temporarily generated in the first stage, and the secondary alert for emergency is continued in the second stage which should not be approached any more. By generating the alarm, it is possible to prevent comfortable driving from being interrupted by the continuation of the alarm sound, and to prevent the alarm from being issued too much to call attention to excessive approach.

Next, FIG. 2 is a diagram showing a configuration corresponding to claims 3 to 6. The configuration of FIG. 2 is obtained by adding an inter-vehicle distance comparison means 18 to the configuration of FIG. First, in claim 3, the inter-vehicle distance comparing means 18 cannot measure the inter-vehicle distance or discontinuously changes greatly, and then the inter-vehicle distance measured within a predetermined time and the inter-vehicle distance cannot be measured or discontinuous. When the difference is small (for example, the difference ≦ 5 m), an alarm suppression signal is sent to the alarm occurrence determination means 9.
Then, the alarm generation determination means 9 suppresses the alarm generation when the alarm suppression signal is given after the alarm generation. In the configuration of claim 1 or claim 2, after the primary alarm is generated,
Once the state becomes unmeasurable or discontinuous,
When the measurement becomes possible immediately and the measured value is close to the previous value, that is, when the state returns to the state continuous with the previous value, the primary alarm is generated again. However, in such a case, it is desirable for the driver to suppress the generation of the primary warning because the relationship with the preceding vehicle has not changed. Therefore, in Claim 3, it is configured as described above. If your own vehicle suddenly approaches the preceding vehicle, or if the newly measured inter-vehicle distance becomes smaller due to an interruption of another vehicle, the difference from the inter-vehicle distance before the discontinuous and drastic change is determined. Since the value becomes larger than the value, the alarm suppression is canceled.

Next, in claim 4, a predetermined number of stable inter-vehicle distance data necessary for calculation are gathered to newly calculate the relative speed, and the primary warning distance and the secondary warning distance are calculated based on the new relative speed. In addition, when it is determined that the latest inter-vehicle distance data is longer than the new primary alarm distance by a predetermined value (for example, about 20 m) or more, the suppression of the alarm generation is canceled within the predetermined time. is there.
As described above, after the distance data once becomes abnormal, new distance data is gathered to calculate the primary warning distance and the secondary warning distance, and the latest inter-vehicle distance data is set to be more than the new primary warning distance. When the value is longer than the value (for example, about 20 m), the preceding vehicle that is following is out of the measurement field of view due to a lane change or the like, and the preceding vehicle that is present in front of the preceding vehicle is newly tracked. Is. In such a case, since it is necessary to watch the inter-vehicle distance for a new preceding vehicle, the alarm suppression is canceled and normal control is performed even within the predetermined time as described above.

Next, in a fifth aspect, the distance change amount recognizing means is configured to recognize that a long distance is discontinuously measured, and in a sixth aspect, the above-mentioned The distance change amount recognition means is configured to recognize that a short distance is discontinuously measured. Then, as described above, when discontinuously measuring a long distance or discontinuously measuring a short distance, a predetermined time measured by the time measuring means from the time when the distance discontinuously changes. During the interval, the inter-vehicle distance measured by the inter-vehicle distance measuring means is compared with the inter-vehicle distance immediately before the above-mentioned distance changes discontinuously, and if the difference is smaller than a predetermined value, the alarm is suppressed. It is configured in. As mentioned above, when measuring a long distance discontinuously,
For example, this is the case when the distance between vehicles is erroneously detected due to reflection from a large, off-road structure such as a destination display board, and when measuring a short distance discontinuously, the vehicle speed decreases. This is a case where the inter-vehicle distance is erroneously detected due to reflection from the road surface in the immediate vicinity of the vehicle due to a change in the vehicle attitude. In such a case, since the previous state is immediately restored, the generation of the primary alarm is suppressed as described above. In addition, it is easy to erroneously measure the above-mentioned distant display board when the inter-vehicle distance measuring means 1 (range-finding radar) is installed in a relatively high portion of the vehicle body, and the road surface is erroneously measured. It is often easy to measure when the inter-vehicle distance measuring means 1 is installed in a low portion of the vehicle body. Therefore, the configuration of either claim 5 or claim 6 may be adopted depending on the installation location of the inter-vehicle distance measuring means 1.

Next, FIG. 3 is a diagram showing a configuration corresponding to claim 7. The configuration of FIG. 3 is obtained by adding the time constant changing means 19 to the configuration of FIG. In the seventh aspect, the distance change amount recognizing means 15 recognizes the case where the long distance is discontinuously measured, the case where the short distance is discontinuously measured, and the case where the other distance is measured. Then, the time constant changing means 19 changes the length of the predetermined time in the time measuring means 16 according to the recognition result. When the discontinuous long distance is measured, the discontinuous short distance is measured, and the other distances are measured, a discontinuous change in inter-vehicle distance is caused by a distant road. This is to determine whether it is due to reflection from an external structure, due to road reflection in the immediate vicinity of the vehicle due to a change in vehicle attitude, or due to other factors. It is configured to change a predetermined time for performing alarm suppression. For example, when a structure outside a distant road is erroneously detected, it takes some time to recover, so the length of the predetermined time in the time measuring means 16 is larger than a standard value (for example, about 2 seconds) ( For example, about 3 to 4 seconds). Further, when the road surface in the vicinity of the vehicle is erroneously detected due to a change in the attitude of the vehicle, the time until the vehicle returns is extremely short, so the length of the predetermined time in the time measuring means 16 is smaller than the standard value (for example, 1 second or less). ). With the above configuration, since precise control can be performed according to the object of erroneous detection, erroneous alarm generation can be reliably suppressed, and alarm delay can be prevented. I can.

As described above, in the present invention, it is necessary to constantly monitor the change status of the distance data with respect to the target object, recognize whether or not the distance data is for the target object on the road surface, and appropriately issue an alarm. Therefore, it is configured so that false alarms and alarm delays do not occur. That is, if the distance to the target object cannot be measured for some reason or if the distance changes discontinuously, the previous alarm distance is maintained so that there is no alarm delay and a single alarm is issued. After that, if the distance data close to the distance data immediately before the drastic change within the predetermined time is measured, it is determined that the situation between the target object and the vehicle has not changed, and the occurrence of the primary alarm is suppressed. By doing so, frequent alarms are eliminated and the reliability of the alarms is secured. In addition, a predetermined time for holding the alarm distance or suppressing the alarm is determined by determining whether the detection error is caused by the reflection of a large structure outside the road such as a destination display board or the latest road surface reflection caused by a change in the vehicle attitude. By making a change, precise control can be performed according to the object of erroneous detection, so that erroneous alarm generation can be surely suppressed and alarm delay can be prevented.

[0023]

FIG. 4 is a block diagram of an embodiment of the present invention. In the present embodiment, the target object on which the host vehicle may collide on the road is equivalent whether it is a falling object or a preceding vehicle or a stopped vehicle, so in the following description,
All targets are described as vehicles. In FIG. 4, the radar device 21 is, for example, a distance measuring device such as a laser radar or a Doppler radar, which transmits a transmission signal to the front of the vehicle and receives a reflection from a preceding vehicle as a reception signal. It has a function of calculating the inter-vehicle distance L based on the difference between the transmission and reception time of the received signal. Further, the vehicle speed sensor 23 is
For example, the speed Va of the host vehicle is measured from the number of rotations of the wheels. Further, the information processing circuit 25 performs various signal processing such as determination of excessive approach to a road obstacle ahead or a preceding vehicle, and is configured by, for example, a computer or the like. Also,
The alarm generation device 27 is a device that receives an alarm signal output when it is determined that an alarm has occurred as a result of information processing by the information processing circuit 25, and issues an alarm. As the alarm generating device 27, for example, a sound alarm by a buzzer, a chime, etc., a voice alarm by recording or synthetic voice, a light alarm by a light emitting device, etc. can be used.

Hereinafter, the information processing circuit 2 will be described with reference to FIG. 5 showing the vehicle running condition and the flowcharts of FIGS.
The process 5 will be described. FIG. 6 is a flowchart corresponding to the functional block diagram of FIG. 1 (corresponding to claim 1). First, as shown in Case 1 of FIG. 5, a flow of processing when the host vehicle M is traveling following the preceding vehicle A will be described. 6, in step 100, the counter variables NGC, NGCT, the relative speed Vr, and the alarm distance D ₀ are cleared, and in step 110, the counter variable C and the measured inter-vehicle distances L _{1 to} L ₄ (L _{1 to} L ₄ are continuous. (4 distance data)
To clear. Next, in step 120, the counter variable C
After counting up, the inter-vehicle distance L is measured by the radar device 21 in step 130. Radar device 21
Outputs inter-vehicle distance data once every 0.1 seconds, for example. Next, in step 140, it is recognized whether or not the inter-vehicle distance can be measured, and if it is measured, it is determined in step 150 whether or not the counter variable C is 1. If the counter variable C is not 1, the measured inter-vehicle distance is discontinuously increased depending on whether or not the difference between the inter-vehicle distance Lc ₋₁ measured last time in step 160 and the inter-vehicle distance L measured this time is larger than L _lim1. Recognize whether it fluctuated. Where L _lim1
Has a maximum relative speed of 180 km / h and is about 5 m, which corresponds to the travel distance in 0.1 seconds. If it is determined that the proper inter-vehicle distance has been measured by the above processing,
In step 170, the inter-vehicle distance L is stored as Lc. Whether or not the counter variable C is 1 is to determine whether or not it is the first measurement after all data of the measured inter-vehicle distance is cleared in step 110. That is, when C = 1, the previous data Lc for determining whether or not the data is discontinuous
_Since there is no _-1 , the calculation in step 160 is skipped.

Next, at step 180, it is judged if four pieces of inter-vehicle distance data necessary for calculating the relative speed have been obtained. In principle, the relative velocity can be calculated if there are two pieces of data, but more accurate data can be obtained as the number of pieces of data increases. However, if the number of data is large, it takes a long time to calculate it. If there are four, sufficiently accurate calculation can be performed. If four pieces are not obtained, the processing of steps 120 to 180 is repeated until four pieces of stable inter-vehicle distance data are obtained, and then step 19 is performed.
When 0, the counter variables NGC and NGCT are reset, and in steps 200 to 215, the relative speed Vr is calculated and the own vehicle speed V is calculated.
A is measured and the alarm distance D ₀ is calculated. The relative speed Vr and the alarm distance D ₀ are calculated by the following (Equation 2) and (Equation 3) equations.

[0026]

[Equation 2]

It should be noted that L _{1 to} L ₄ are inter-vehicle distance data, respectively, and the equation of Vr shown in (Equation 2) averages the time change (relative speed) of four inter-vehicle distance data by the least square method. To do. The denominator “10” indicates the coefficient in the least squares method, and “0.1” indicates the sampling time of 0.1 seconds. Further, the equation of D ₀ shown in the equation (3) is a distance at which the vehicle can be stopped safely when the host vehicle decelerates upon recognizing that the preceding vehicle has applied the sudden braking. It is assumed that the deceleration of the preceding vehicle and the own vehicle are equal. Further, in the above equation (3), α ₀ is the deceleration of the vehicle. This value is a preset setting value, for example, α ₀ = 0.7G. Further, T ₀ is the reaction time of the driver (the delay time from the driver's recognition of the change of the preceding vehicle to the braking operation or the avoidance operation). This value is also a preset setting value, for example, T ₀ = 1.0 second. Next, step 2
At 55, the alarm distance D ₀ is compared with Lc, and if Lc is shorter, an alarm is issued at step 265. That is, Lc <
An alarm is generated at D ₀ . Next, in step 280, the inter-vehicle distances L ₂ → L ₁ , L ₃ → L ₂ , L ₄ are set to the counter variable C = 3.
→ Replace with L ₃ . After that, steps 120 to 2
A new L ₄ is measured by the processing of 80, and the warning distance calculation and the warning occurrence determination are performed from the latest four inter-vehicle distance data including the new L ₄ . The above part is the control when the distance can be normally measured, but in steps 300 to 330, the distance cannot be measured in steps 140 and 160, or the inter-vehicle distance L measured this time is the inter-vehicle distance Lc measured last time. _This is a process of removing the noise data from the inter-vehicle distance data for calculating the relative speed when it is recognized that the change is discontinuous with respect to _-1 . First, in step 300, step 14
At 0 and 160, the number of times the distance measurement is impossible or the discontinuous change in the inter-vehicle distance L is recognized is counted by the counter variable NGC, and it is determined at step 310 whether or not it exceeds NGC _lim . If it does not exceed, the counter variable C is decremented by 1 in step 320, and the process returns to step 120 to measure the following distance. If it exceeds NGC _lim , step 3
The counter variable NGC is cleared at 30 and step 110
In counter variable C, and headway distance L ₁ ~L ₄ Clear, L ₁
Repeat the measurement from. Here, NGC _lim is set to 2 which corresponds to 0.2 seconds. That is, while collecting four inter-vehicle distance data for calculating the relative speed, noise data up to twice is removed, and if there is more noise data, collect distance data from the beginning. become.
Note that the above removal is to calculate an accurate relative speed by using stable inter-vehicle distance data. However, the positional relationship of vehicles changes constantly, so by removing the data up to twice, the maximum is 0.
The relative speed is calculated within 5 seconds. Also, the noise data is removed by the processing of steps 140, 160, 320 of the flow.

However, while the above processing calculates the appropriate warning distance, there is a problem that the warning cannot be issued while the inter-vehicle distance data is being collected. Therefore, in the present embodiment, the alarm distance is maintained for a predetermined period of time so that the alarm can be surely issued when it becomes more dangerous than the situation before the inter-vehicle distance data greatly changes due to an interrupting vehicle or the like. I am configuring. Hereinafter, steps 500 to 530, which are characteristic parts of the present embodiment as described above, will be described. First, in step 500, steps 140, 16
The counter variable NGCT counts the cumulative number of times that the inter-vehicle distance cannot be measured or the discontinuous change in the inter-vehicle distance L is recognized at 0. This is an alarm distance holding counter that accumulates four pieces of inter-vehicle distance data until the relative speed is measured. Next, in step 510, the above counter variable N
It is determined whether or not the count number of GCT exceeds NGCT _lim . If it does not exceed the limit, the processing from step 300 onward is performed. If the inter-vehicle distance Lc is not measured in steps 120 to 180 and the four inter-vehicle distance data for calculating the relative speed are not available, it is determined in step 515 whether the warning distance D ₀ is held. To do. If it is held, the alarm generation determination / alarm generation processing in steps 255 to 265 is performed, and in step 530, the process returns to step 120 without replacing step 280,
Measure the following inter-vehicle distance data. Step 510
If the counter variable NGCT exceeds NGCT _lim , the process returns to step 100 and the counter variables NGC, NG
The CT, the relative speed Vr, and the held alarm distance D ₀ are cleared, and in step 110, the counter variable C and the inter-vehicle distance L ₁
~ Clear L ₄ and repeat measurement from L ₁ . In addition, NG
CT _lim is equivalent to 2.0 seconds, which is considered to be the same in normal follow-up driving such as Case 1, where 2 is unlikely to change.
Set to 0 (0.1 seconds x 20 times).

Next, as in case 2 of FIG. 5, the flow of processing when the preceding vehicle A changes lanes and is no longer in front of the host vehicle M will be described. In this case, it is always recognized in step 140 that the distance could not be measured. Therefore, steps 120 to 140, 500, 51
Rotate 0, 300-320 twice, step 3 for the third time
30 and 110 are counter variables NGC, counter variables C,
Clear the inter-vehicle distance L _{1 to} L ₄ and repeat steps 120 to 1
Processes 40, 500, 510 and 300 to 320 are performed. The following distance unmeasurable number during this period step 500, is counted by the counter variable NGCT, after 2 seconds the process returns to step 100 to cross the NGCT _{li m,} hereinafter the process is repeated. In this embodiment, the radar device has
The data is output every 1 second, and the other processes are processed at a speed sufficiently high for this time. The process during follow-up running is step 530, 2 after warning judgment.
The process moves from 80 to step 120, C = 4, new inter-vehicle distance data is obtained in step 130, and step 14
Processing from 0 to 265 is performed. Here, if the preceding vehicle does not exist due to the lane change, the inter-vehicle distance L cannot be measured in step 130, and steps 140 to 5
Moving to 00, NGCT = 1. N in step 510
Since GCT _lim is 20, which corresponds to 2.0 seconds, the process moves to step 300 and NGC = 1. Step 3
Since the NGC _lim of 10 is 2 corresponding to 0.2 seconds, C = 3 at step 320 and C = 4 at 120, and the distance is measured again. If the inter-vehicle distance L is not obtained here either, in the same manner as above, in steps 500 to 310, NGCT =
2, NGC = 2, 2 turns, 3rd NGCT = 3,
NGC = 3 and steps 310 to 330, 110
Move to processing. Hereinafter, this process continues, and NGCT = 21
Then, step 51 which is 20 corresponding to 2.0 seconds
Since the NGCT _lim of 0 is exceeded, the process moves to step 100.

Next, as in case 3 of FIG. 5, the flow of processing when the preceding vehicle A changes lanes and the host vehicle M follows the preceding preceding vehicle B will be described. In this case, the measured inter-vehicle distance L is once discontinuously increased, and then continuous inter-vehicle distance data is measured.
If the difference between the current inter-vehicle distance data and the previous inter-vehicle distance data is ± 5 m or more, it is determined that the data is discontinuous. For example, if the measurement data is "31 m, 30
m, 29m, 31m, 62m , 63m, 62m, ", the underlined portion is discontinuous data, and the others are continuous and stable data. First, step 16
At 0, a discontinuous change in the inter-vehicle distance L is recognized. In this case, the target A suddenly changes from the stable inter-vehicle distance measurement to the target B.
Since the comparison is made with L ₃ replaced by, the process proceeds to step 500 even if stable data continues thereafter. Then, steps 120 to 160, 500, 510, 300
~ 320 twice, steps 330, 110
With counter variable NGC, counter variable C, inter-vehicle distance L ₁
~ Clear L ₄ . Then, the distance measured next becomes L ₁ , and after processing steps 150, 170, and 180,
Since the warning distance is maintained in step 515, the warning occurrence determination / warning is performed in steps 255 to 265.
In step 530, the process returns to step 120 without replacing step 280, and the next inter-vehicle distance data is measured.

The next measured L ₂ is compared with L ₁ in step 160, and therefore the process proceeds to step 170, and steps 180, 515, 255 to 255 are carried out similarly to L _1.
265 is performed. The same applies to L ₃ measured next. As described above, the warning judgment is performed for the measured inter-vehicle distance data every time based on the held warning distance for a predetermined time after there is a change that cannot be measured or is discontinuous. , If it becomes more dangerous than the situation before the distance between vehicles changed discontinuously,
A warning can be issued reliably. In addition, if the inter-vehicle distance cannot be measured or the inter-vehicle distance changes during these processes, when the cumulative time exceeds 2 seconds, step 10
Returning to 0, all variables are cleared and the process is performed from the beginning, and this process is repeated.

Next, FIG. 7 is a flow chart showing an operation corresponding to claim 2.

First, as shown in Case 1 of FIG. 5, the flow of processing when the host vehicle M is traveling following the preceding vehicle A will be described. The description of the same steps as those in FIG. 6 will be omitted, and only the characteristic parts of this embodiment will be described. 7, in step 102, counter variables NGC, NGCT, relative speed Vr, primary warning distance D
₁ , the secondary alarm distance D ₂ is cleared, and in step 110, the counter variable C and the measured inter-vehicle distances L _{1 to} L ₄ (L _{1 to} L ₄ are _four continuous distance data) are cleared. Next, steps 120 to 1 are performed until four pieces of stable inter-vehicle distance data are obtained.
After repeating the processing of 80, the counter variables NGC and NGCT are reset in step 190, and steps 200-
At 230, the relative speed Vr is calculated, the own vehicle speed Va is measured, and the primary warning distance D ₁ and the secondary warning distance D ₂ are calculated. The relative speed Vr, the primary warning distance D ₁ , the secondary warning distance D ₂
Is calculated by the following equations (4) to (6).

[0034]

[Equation 4]

The above equation (4) is the same as the above equation (2).

D ₁ shown in the equations (5) and (6),
The formula of D ₂ is a distance that can be safely stopped when the own vehicle slows down by recognizing that the preceding vehicle has applied the sudden braking, and the secondary warning distance D ₂ corresponding to the emergency warning is The deceleration is larger than the primary warning distance D ₁ for alerting and the reaction time is short. It is assumed that the deceleration of the preceding vehicle and the own vehicle are equal. Also, the above equation (5),
In equation (6), α ₁ and α ₂ are decelerations of the vehicle,
α ₂ > α ₁ . These values are preset values, for example, α ₁ = 0.5G and α ₂ = 0.8G. Also,
T ₁ and T ₂ are the reaction time of the driver (the delay time from the driver's recognition of the change in the preceding vehicle to the brake operation or avoidance operation), and T ₁ > T ₂ . These values are also preset values, for example, T ₁ = 1.2 seconds and T ₂ = 0.9.
Seconds. As described above, because of the relationship of α ₂ > α ₁ and T ₁ > T ₂ , D ₁ > D ₂ .

Next, in step 240, the secondary warning distance D
₂ and the inter-vehicle distance L measured this time are compared, and if the L measured this time is shorter, a secondary alarm is generated in step 250,
If it is longer, the primary alarm distance D ₁ is compared with L in step 260, and if L is shorter, a primary alarm is generated in step 270. That is, a primary alarm is issued when D ₂ ≤L <D ₁ and a secondary alarm is issued when L <D ₂ . Hereinafter, steps 240 to 270 and steps 500 to 500, which are characteristic parts of the present embodiment as described above, will be described.
530 will be described. First, in step 500, the number of times of accumulating the inability to measure the inter-vehicle distance and the discontinuous change in the inter-vehicle distance L in steps 140 and 160 is counted as a counter variable N.
Count with GCT. This is an alarm distance holding counter that accumulates four pieces of inter-vehicle distance data until the relative speed is measured. Next, at step 510, it is judged if the count number of the counter variable NGCT exceeds NGCT _lim . If not, step 3
The processing after 00 is performed. And steps 120-1
If the inter-vehicle distance Lc is not measured at 80 and the four inter-vehicle distance data for calculating the relative speed are not available, it is determined at step 520 whether the primary warning distance D ₁ is held. If so, step 240-
The alarm generation determination / alarm generation processing of 270 is performed, and in step 530, the process returns to step 120 without replacing step 280, and the next inter-vehicle distance data is measured.
At step 510, the counter variable NGCT is changed to NGCT.
_{If lim} is exceeded, the process returns to step 100 to clear the counter variables NGC, NGCT, the relative speed Vr and the held primary alarm distance D ₁ and secondary alarm distance D ₂ , and in step 110 the counter variable C, the vehicle distance. Clear the distances L _{1 to} L ₄ and repeat the measurement from L ₁ . Note that the NGCT _lim is 20 (0.1 seconds × 2), which is equivalent to 2.0 seconds in which it is considered that there is no significant change in normal follow-up running such as Case 1.
(0 times).

Next, as in case 2 of FIG. 5, when the preceding vehicle A changes lanes and is no longer in front of the host vehicle M, in step 510, the warning distance holding counter NGCT is set. Step 1 if NGCT _lim is exceeded
02, clear alarm distances D ₁ and D ₂ ,
After the warning is judged, the process during the follow-up running is step 5
The process is the same as that of FIG. 6 except that the process proceeds from step 30, 280 to step 120, C = 4, new inter-vehicle distance data is obtained at step 130, and steps 140 to 270 are performed.

Next, as in case 3 of FIG. 5, the flow of processing when the preceding vehicle A changes lanes and the host vehicle M follows the preceding preceding vehicle B will be described. First, in step 160, a discontinuous change in the inter-vehicle distance L is recognized. At step 160, since the comparison is made with L ₃ replaced at step 280, the process moves to step 500 even if stable data continues thereafter. Then, the steps 120 to 160, 500, 510, 300 to 320 are performed twice, and the counter variables NGC, C, and the inter-vehicle distances L _{1 to} L ₄ are cleared at steps 330 and 110 for the third time. Then, the next measured distance becomes L ₁ , and after processing steps 150, 170 and 180, step 5
Since the warning distance is held in step 20, step 240-
The alarm generation judgment / alarm generation of 270 is performed, and step 5
Step 12 without replacing Step 280 with Step 30
Returning to 0, the next inter-vehicle distance data is measured.

[0040] Then L ₂ to be measured, the process to step 170 to become compared with L ₁ is shifted in step 160, also step 180,520,240～ to L ₁
The process of 270 is performed. The same applies to L ₃ measured next. As described above, the warning judgment is performed for the measured inter-vehicle distance data every time based on the held warning distance for a predetermined time after there is a change that cannot be measured or is discontinuous. , If it becomes more dangerous than the situation before the distance between vehicles changed discontinuously,
A warning can be issued reliably. In addition, if the inter-vehicle distance cannot be measured or the inter-vehicle distance changes during these processes, when the cumulative time exceeds 2 seconds, step 10
Returning to step 2, all variables are cleared and the process is performed from the beginning, and this process is repeated.

Next, FIG. 8 shows claims 3 and 4.
3 is a flowchart corresponding to (corresponding to the functional block diagram of FIG. 2). Here, the description of the same processing as that in FIGS. 6 and 7 is omitted, and the characteristic part of the present embodiment will be mainly described. First, in FIG. 8, in order to suppress an unnecessary primary alarm, when a primary alarm or a secondary alarm is issued in steps 250 and 270, the primary alarm suppression flag onf is set to 1 in step 600. Further, four pieces of stable inter-vehicle distance data are collected, and steps 200 to 2 are carried out.
At 30, the relative speed Vr is calculated, the own vehicle speed Va is measured, and the primary warning distance D ₁ and the secondary warning distance D ₂ are calculated, and after the alarm occurrence determination / alarm occurrence is performed, step 6 is performed.
At 50, counter variable C = 3, inter-vehicle distance data L ₂ → L ₁ ,
L ₃ → L ₂ and L ₄ → L ₃ are replaced, and the latest inter-vehicle distance data L ₄ is stored as LL.

First, as in case 1 of FIG. 5, the preceding vehicle
If you are following both cars,
If the distance cannot be measured or if there are discontinuous changes
The flow of processing will be described. In such a case, in a short time
Measure the inter-vehicle distance data with the original preceding vehicle again
However, for the driver, the situation with the preceding vehicle changed
Since it is not, it is annoying that the primary alarm is generated again.
It is desirable that the next alarm be suppressed. Therefore, first
At steps 140 and 160, the distance L between vehicles cannot be measured or is disconnected.
Recognize continuous and significant changes. And step 120-
Rotate 160, 500, 510, 300-320 twice
The counter variable N at steps 330 and 110 for the third time.
GC, counter variable C, inter-vehicle distance L₁~ L_FourClear
It Then, the distance measured next is L₁Next step
After processing 150, 170, 180, step 520
Since the alarm distance is held in step 240
Determine the next alarm occurrence. The secondary alert is an emergency alert
And the inter-vehicle distance Lc is the secondary warning distance D₂Must be smaller
Without an alarm. Distance Lc is D₂In case of above
At step 260, it is determined whether a primary alarm has occurred. Inter-vehicle distance L
c is D₁If less, then in step 610 primary
It is determined whether or not the alarm suppression flag onf is 1. onf
If not 1, an alarm is issued and then step 600
The primary alarm suppression plug onf is set to 1. Ste
If the primary alarm suppression flag onf is 1 at step 610.
In other words, the measured inter-vehicle distance is discontinuous after an alarm is issued.
If it is within the predetermined time after changing to
The last of the inter-vehicle distance data that calculated the warning distance in 620
LL and L ₁And the difference is L_lim2If less than
The primary alarm is suppressed when it is judged that the situation has not changed. Well
L_lim2If it is above, it is judged that the situation has changed and
At 270, a primary alarm is issued. Then, step 53
0, 120-160. In this case step 16
0 for L₁Since the comparison will be with₂Tona
Then, by the same processing, L_FourStable distance between cars
The distance is collected and a new warning distance is calculated. Also, in FIG.
In Case 3, the preceding vehicle A and the preceding vehicle B further ahead of it
If the vehicle-to-vehicle distance is short, the preceding vehicle A is simply the preceding vehicle.
The situation has not changed since it is the same as B.
It is conceivable that the primary alarm should be suppressed.
Yes. Therefore L_lim2It is thought that about 15 m is appropriate.
That is, if the distance between the preceding vehicles A and B is 15 m or more
If so, it is determined that the vehicle has changed to another vehicle.

Next, as in case 3 of FIG. 5, the processing when the preceding vehicle A immediately before is changed from the lane to deviate from the measurement field of view and follows the preceding vehicle B in front of it is to run. Explain the flow. First, while following the preceding vehicle A, the inter-vehicle distance data is stably obtained. However, when the preceding vehicle A becomes the target as a result of the lane change of the preceding vehicle A, the inter-vehicle distance is temporarily changed. Grows larger. In step 160, the previous inter-vehicle distance L ₃ is compared with the inter-vehicle distance L measured this time. Therefore, a difference of 5 m or more occurs temporarily, and the process proceeds to step 500. Then, as in case 1, steps 120-160, 500, 510, 300-32
After turning 0 twice, steps 330, 110-18
The warning generation determination / warning generation processing from 0, 520 to 240 is performed, the process proceeds from step 530 to step 120, and the inter-vehicle distance is similarly collected up to L ₄ . Here, for example, even when the preceding vehicle A has changed lanes and the inter-vehicle distance between the preceding vehicle A and the preceding vehicle B is short and the newly measured difference between L ₁ and LL is less than L _lim2 , the alarm is suppressed. ,
When the inter-vehicle distance becomes shorter due to the approaching vehicle B gradually or the interruption by another vehicle, the next measured L
₂ , the difference between L ₃ and the distance LL of the preceding vehicle A immediately before the lane change becomes larger than L _lim2 , so that the alarm suppression is released and the alarm is reliably issued.

Next, steps 630 to 650 are processing parts corresponding to claim 3. If the measured inter-vehicle distance Lc is larger than the primary warning distance, it is determined in step 630 whether or not a new inter-vehicle distance has been set (that is, C = 4). If C is not 4, the process returns to step 120 and the inter-vehicle distance data is collected until four or more relative speed numerical values are obtained. If C is 4, the inter-vehicle distance L is determined in step 640.
c is compared with the primary warning distance D _1, and if the inter-vehicle distance is more than the primary warning distance by a certain margin L _off or more, it is determined that the situation has completely changed, and even if it is within a predetermined time, step At 650, the primary alarm suppression flag onf is cleared. In this case, L _off of about 20 m is appropriate. This process also has the effect of preventing the primary alarm from hunting and being generated when the vehicle is following and traveling with the inter-vehicle distance of around D ₁ .

Next, FIG. 9 is a flowchart of the process corresponding to claim 4, and FIG. 10 is a flowchart of the process corresponding to claim 5. In addition, in FIG. 9 and FIG.
The description of the same parts as those in claims 2 and 3 will be omitted, and the description will focus on the characteristic parts of this embodiment. In the embodiment of FIG. 9, when the measured inter-vehicle distance L changes discontinuously with respect to the previously detected inter-vehicle distance in step 160, only in the case where the changed direction is more than L _lim3 in step 700, the predetermined time is _exceeded. The counter variable NGCT is counted up. In the embodiment of FIG.
When the value is 0 and is close to L _lim4 or less, the predetermined time counter variable NGCT is incremented. this is,
Since the condition of incorrect measurement of the inter-vehicle distance is specified by the direction of the change, the property that the measured inter-vehicle distance returns to the vicinity of the distance before the change is almost constant if there is no change in the situation is used. When the direction and magnitude of the change of the above condition meet the condition, and the inter-vehicle distance returns to the vicinity of the inter-vehicle distance before the change within a predetermined time, the alarm suppression is performed. In this case, the NGCT _{lim of} FIG. 9 and FIG.
The value of is set to a value according to each state. For example, the value of NGCT _lim in FIG. 9 is about 3 to 4 seconds, and the value of NGCT _lim in FIG.
The value of CT _lim should be about 1 second or less.

As shown in FIG. 9, the case where the long distance is measured discontinuously means, for example, that the inter-vehicle distance is erroneously detected due to the reflection from a large structure outside the road such as a destination display board. In this case, the case where the short distance is discontinuously measured as shown in FIG. 10 means that the inter-vehicle distance is erroneously detected due to the reflection from the road surface in the immediate vicinity of the vehicle due to the vehicle attitude change due to the vehicle deceleration or the like. This is the case. In such a case, since the previous state is immediately restored, the generation of the primary alarm is suppressed as described above. In addition, it is easy to erroneously measure the above-mentioned distant display board when the inter-vehicle distance measuring means 1 (range-finding radar) is installed in a relatively high portion of the vehicle body, and the road surface is erroneously measured. It is often easy to measure when the inter-vehicle distance measuring means 1 is installed in a low portion of the vehicle body. Therefore, either the configuration shown in FIG. 9 or the configuration shown in FIG. 10 may be adopted depending on the installation location of the inter-vehicle distance measuring means 1.

11 and 12 are flowcharts corresponding to the functional block diagram of FIG. 3 (corresponding to claim 6), and FIG. 12 shows the contents of step 720 of FIG.
As explained earlier, if the distance between vehicles changes discontinuously and greatly, it is highly possible that the distance to an off-road object such as a far display board is being measured, and the distance between vehicles is accurate. It will take some time to return so as to measure. On the other hand, if the distance changes discontinuously and significantly, it is highly possible that the distance to the nearest road surface is being measured due to the posture change of the vehicle, and it will take time to recover so that the accurate distance between vehicles is measured. The time is extremely short. Therefore, when a large inter-vehicle distance change is recognized discontinuously in step 160, the measured inter-vehicle distance L is determined in step 800 as shown in FIG.
_Is greater than L _{lim3, and} if it is greater than L _lim3, the maximum value NGCT _lim of the predetermined time counter variable is set to C ₁ in step 810. Further, in step 820, it is determined whether or not it is less than L _{lim4, and} if it is less than L _lim4 , in step 830, the maximum value NGC of the predetermined time counter variable is determined.
Set T _lim to C ₂ . If neither, step 1
If the inter-vehicle distance cannot be measured at 40, step 7
At 30 and 840, NGCT _lim is set to C ₀ . For the above reason, it is appropriate that C ₁ is about 3 to 4 seconds, C ₂ is 1 second or less, and the standard value C ₀ is about 2 seconds as described above.

[0048]

As described above, in the present invention, since the warning distance is maintained for a predetermined time, the inter-vehicle distance cannot be measured or the measured inter-vehicle distance is discontinuous for some reason. Even if it changes drastically, it is possible to issue an alarm without delay in the case of excessive proximity. Further, even if the inter-vehicle distance cannot be measured or the inter-vehicle distance changes discontinuously within a predetermined time, unnecessary primary alarms are suppressed if the relative situation with the preceding vehicle has not changed significantly. In addition, when the relative situation with the preceding vehicle changes and the vehicle is approaching excessively, such as a sudden interruption vehicle, the alarm suppression can be canceled and the alarm can be issued even within the predetermined time. it can. Furthermore, it is determined whether the inter-vehicle distance is erroneously detected due to the reflection of a structure outside the road or the road surface is erroneously detected due to a change in the vehicle attitude, and the alarm distance holding time or the predetermined alarm suppression time is set according to the situation. As a result, it is possible to obtain many effects such as suppressing both the unnecessary primary alarm and the reliable primary alarm in the case of excessive proximity.

[Brief description of drawings]

FIG. 1 is a functional block diagram corresponding to claim 1 and claim 2 of the present invention.

FIG. 2 is a functional block diagram corresponding to claims 3 to 6 of the present invention.

FIG. 3 is a functional block diagram corresponding to claim 7 of the present invention.

FIG. 4 is a block diagram showing the configuration of an embodiment of the present invention.

FIG. 5 is a diagram showing a follow-up traveling situation of a preceding vehicle in the present invention.

FIG. 6 is a flowchart showing an example of arithmetic processing corresponding to claim 1 of the present invention.

FIG. 7 is a flowchart showing an example of arithmetic processing corresponding to claim 2 of the present invention.

FIG. 8 is a flowchart showing an example of arithmetic processing corresponding to claims 3 and 4 of the present invention.

FIG. 9 is a flowchart showing an example of arithmetic processing corresponding to claim 5 of the present invention.

FIG. 10 is a flowchart showing an embodiment of arithmetic processing corresponding to claim 6 of the present invention.

FIG. 11 is a flowchart showing an example of arithmetic processing corresponding to claim 7 of the present invention.

FIG. 12 is a flowchart showing details of a part of FIG. 11.

[Explanation of symbols]

1 ... Inter-vehicle distance measuring means 16 ... Time measuring means 3 ... Own vehicle speed detecting means 17 ... Warning distance holding means 5 ... Relative speed calculating means 18 ... Inter-vehicle distance comparing means 7 ... Warning distance calculating means 19 ... Time constant changing means 9 ... Warning Generation determination means 21 ... Radar device 11 ... Warning generation means 23 ... Vehicle speed sensor 13 ... Unmeasurable recognition means 25 ... Information processing circuit 15 ... Inter-vehicle distance change amount recognition means 27 ... Warning generation device

Claims (7)

[Claims] 1. An inter-vehicle distance measuring means mounted on a vehicle for measuring a distance between a host vehicle and a target object; and an unmeasurable recognizing means for recognizing that the distance between the inter-vehicle distance measuring means cannot be measured. The distance change amount recognition means for recognizing that the distance measured by the inter-vehicle distance measuring means discontinuously greatly changes, and the above two recognition means enable the distance between the own vehicle and the target object to be measured and discontinuously. When it is recognized that the target vehicle speed has not changed significantly, relative speed calculation means for calculating the relative speed between the own vehicle and the target object from the change in the distance between the own vehicle and the target object, and the own vehicle speed are detected. The distance could not be measured by the own vehicle speed detecting means, the warning distance calculating means for calculating the warning distance based on the own vehicle speed and the relative speed, and the unmeasurable recognition means or the distance change amount recognition means. , Is a time measuring means for measuring the elapsed time from the time when it is recognized that the measured distance has changed discontinuously and drastically, and while the above elapsed time is within a predetermined time, or a newly calculated relative speed. Until the warning distance based on the warning distance is calculated, the warning distance holding means for holding the warning distance calculated by the warning distance calculating means, and the warning based on the distance between the own vehicle and the target and the warning distance. An approach warning device for a vehicle, comprising: an alarm generation determination means for determining whether or not to issue the alarm; and an alarm generation means for generating an alarm according to the determination of the alarm generation determination means. 2. The approach warning device for a vehicle according to claim 1, wherein the warning distance calculation means is a primary warning distance corresponding to a primary warning for alerting and a secondary warning corresponding to a secondary warning for emergency. An approach warning device for a vehicle, wherein: a warning distance is calculated, and the warning occurrence determination means determines whether to issue the primary alarm or the secondary alarm. 3. The approach warning device for a vehicle according to claim 1 or 2, wherein the distance measurement cannot be made by the unmeasurable recognition means or the distance variation recognition means, or the measured distance is discontinuous. When a significant change is recognized, the inter-vehicle distance measured by the inter-vehicle distance measuring means and the inter-vehicle distance immediately before the recognition are displayed for a predetermined time measured by the time measuring means from the time of the recognition. If the difference is smaller than a predetermined value, an inter-vehicle distance comparison means for sending an alarm suppression signal to the alarm occurrence determination means is provided, and the alarm occurrence determination means, after the alarm is issued, suppresses the alarm. An approach warning device for a vehicle, which is configured to suppress generation of a primary warning when a signal is given. 4. The approach warning device for a vehicle according to claim 3, wherein in the warning occurrence determination means, the warning distance calculation means newly calculates the primary warning distance and the secondary warning distance, and the new primary warning distance is calculated. When the inter-vehicle distance that is longer than the alarm distance by a predetermined value or more is measured, it is configured such that the alarm suppression signal is invalidated even during the predetermined time period. Proximity warning device. 5. The vehicle approach warning device according to claim 3 or 4, wherein the distance change amount recognition means recognizes that a long distance is discontinuously measured. The comparing means, between the time when the distance changes discontinuously long and the predetermined time measured by the time measuring means, immediately before the inter-vehicle distance measured by the inter-vehicle distance measuring means and the above-mentioned distance change discontinuously. Compared with the following distance,
When the difference is smaller than a predetermined value, an alarm suppression signal is sent to the alarm occurrence determination means, and the alarm occurrence determination means is provided when the alarm suppression signal is given after the alarm is issued. Is configured to suppress the generation of a primary alarm, and is a vehicle proximity alarm device characterized by the above. 6. The approach warning device for a vehicle according to claim 3 or 4, wherein the distance change amount recognizing means recognizes that a short distance is discontinuously measured. The comparison means, between the time when the distance discontinuously changes shortly and the predetermined time measured by the time measuring means, immediately before the inter-vehicle distance measured by the inter-vehicle distance measuring means and the above distance discontinuously change. Compared with the following distance,
When the difference is smaller than a predetermined value, an alarm suppression signal is sent to the alarm occurrence determination means, and the alarm occurrence determination means is provided when the alarm suppression signal is given after the alarm is issued. Is configured to suppress the generation of a primary alarm, and is a vehicle proximity alarm device characterized by the above. 7. The approach warning device for a vehicle according to claim 3 or 4, wherein the distance change amount recognizing means measures a long distance discontinuously and a discontinuously short distance. The case is distinguished from the case where a distance other than that is measured, and is recognized, and a time constant changing unit that changes the length of the predetermined time in the time measuring unit according to the recognition result is provided, The distance comparison means, between the time when the distance discontinuously changes and the predetermined time measured by the time measuring means, immediately before the inter-vehicle distance measured by the inter-vehicle distance measuring means and the above-mentioned distance discontinuously change. When the difference is smaller than a predetermined value, an alarm suppression signal is sent to the alarm generation determination means, and the alarm generation determination means outputs the alarm after the alarm is generated. Suppression An approach warning device for a vehicle, which is configured to suppress generation of a primary warning when a signal is given.