JP2002358600A - Following distance alarm device and its method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To restrict an alarm from being raised unnecessarily in a following distance alarm device, which urges a driver to perform an evading operation by raising the alarm when a vehicle approaches a preceding vehicle, etc., too much during traveling. SOLUTION: In the following distance alarm device, a danger state is reported to the driver by at least one of an alarm sound and lamp lighting in response to the distance when the vehicle approaches too much an alarm object in a present lane through the use of a measurement sensor which detects the distance from the alarm object being the preceding vehicle or an obstacle, a relative speed and a direction angle. Alarm is restricted even within an alarm raising distance based on a present vehicle speed when it is correspond to an alarm restriction condition which is decided by the existence of a brake operation in the self-vehicle or the relative speed with the alarm object.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an inter-vehicle distance alarm device and a method for issuing an alarm when a driver approaches a vehicle ahead or an obstacle such as an obstacle while traveling, and prompts a driver to avoid the vehicle.

[0002]

2. Description of the Related Art An inter-vehicle distance warning device is disclosed in
As described in Japanese Patent Application Publication No. 66496, the distance from a vehicle ahead or a warning target which is an obstacle is detected by some distance measuring sensor, and an alarm sound is generated or a warning lamp is turned on when the vehicle approaches too far. This is a device that alerts the driver to the warning. Further, there is a type using a laser radar as a distance measuring sensor.

However, in the device described in Japanese Patent Application Laid-Open No. 11-66496, a warning is issued when the vehicle approaches a vehicle ahead or an obstacle, which is an obstacle, and meets the conditions for issuing a warning. In addition to giving a sense of incongruity to the driver, the driver may become accustomed to it, and even if the warning sounds in a situation where a warning is really needed, the driver may not be aware of the warning.

To solve this problem, Japanese Patent No. 3113 is disclosed.
Japanese Patent Application Publication No. 702 discloses that, for example, during a period in which the driver of the own vehicle is performing a deceleration operation and a predetermined period thereafter, the issuance of an alarm is stopped.

[0005]

However, the one disclosed in Japanese Patent No. 3113702 does not stop setting a predetermined condition based on the speed of the own vehicle and issuing an alarm.

When a warning is issued by approaching a vehicle ahead or an obstacle, which is an obstacle, the danger is higher when the speed of the vehicle is high than when the speed of the vehicle is low.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and an object of the present invention is to reduce the speed of an own vehicle even when the distance between the host vehicle and an alarm target, which is an obstacle, is within an alarm generation area. It is an object of the present invention to provide an inter-vehicle distance alarm device and a method thereof that can provide a driver with appropriate and effective attention by setting some conditions based on the conditions to suppress the generation of an alarm.

[0008]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention uses a measurement sensor capable of detecting a distance, a relative speed and an azimuth angle with respect to a preceding vehicle or an alarming object which is an obstacle. When the vehicle is too close to the warning object, the inter-vehicle distance warning device notifies the driver of the danger condition by at least one of a warning sound and lamp lighting according to the distance. When an alarm suppression condition determined by the presence or absence of a vehicle brake operation or the relative speed with respect to the alarm target is met, the alarm can be set to be suppressed even within the alarm generation distance. .

In other words, the inter-vehicle distance warning device is set so as not to generate a warning under certain conditions, even if the distance between the vehicle in front or a warning object, which is an obstacle, is within the warning generation distance. Therefore, the number of times of alarm generation can be suppressed, and an alarm can be sounded in a situation where an alarm is really needed. As a result, it is possible to provide an inter-vehicle distance warning device and a method thereof that can appropriately and effectively call attention to a driver.

Preferably, the vehicle speed may be divided into a plurality of regions, and different alarm suppression conditions may be set in each region.

[0011] Preferably, the alarm suppression condition is set to a plurality of alarm stages according to the degree of danger. Then, when the alarm stage is switched from a higher-order alarm to a lower-order alarm, the alarm suppression condition may be changed according to the elapsed time after the switching.

Further, preferably, when the alarm target is a stationary object, it is possible to set so as to inhibit the alarm for the stationary object separately from the alarm suppression condition. Then, even when the alarm for the stationary object is set to be suppressed, the lower limit speed of the vehicle speed at which the alarm is forcibly activated may be set, or the alarm for the stationary object may be set to be suppressed. Even if you do
An alarm may be generated when the distance becomes equal to or less than the fixed inter-vehicle distance.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to an embodiment shown in the drawings.

FIG. 1 illustrates an inter-vehicle distance warning device 1 which is a system to which the present invention is applied. Here, a millimeter-wave radar is used as a measurement sensor, and the vehicle
1 shows a configuration of an inter-vehicle distance alarm device that emits a millimeter wave radar signal from an antenna unit 4 toward the vehicle and issues an alarm when the own vehicle 2 approaches the preceding vehicle 3 too much.

In FIG. 1, reference numerals 5, 10 to 15 designate the functions of an arithmetic unit constituting the center of the alarm device 1. Further, the reflected wave is received by the antenna unit 4 of the millimeter wave radar, and the measurement 5 of the following distance, the relative speed and the azimuth angle with the preceding vehicle 3 is executed.

Here, the case where the millimeter wave radar is used as the measurement sensor is exemplified, but a laser radar may be used. The present invention can be applied to any device that can determine the inter-vehicle distance, relative speed, and azimuth angle between the own vehicle 2 and the preceding vehicle 3 by measurement or calculation.

In FIG. 1, the preceding vehicle 3 is described as a warning target, but a stopped vehicle, a roadside sign, or an obstacle such as a viaduct may be used as a warning target.

Further, the angular velocity 7 is measured by an angular velocity sensor 6 provided in the vehicle 2, and the measured angular velocity 7
Is used to estimate the curvature R of the traveling road. As a result, even if the preceding vehicle is measured at the adjacent lane position while traveling on a curve, for example, the preceding vehicle position is corrected using the estimated radius of curvature R, and as a result, the vehicle is determined to be in the own lane. And so on.

Based on these determinations, an alarm determination 14 is made using the alarm determination algorithm 13, the vehicle speed signal, and the brake signal 26. An alarm instruction 15 is generated based on the alarm judgment, and an alarm signal 16 is issued to generate, emit, and / or display an alarm sound on the driver display 17.

Here, whether the target is a moving object or a stationary object can be determined by comparing the detected relative speed with the target and the vehicle speed based on the vehicle speed signal.

FIG. 2 shows an example of the driver display 17 which is an alarm display. The driver display 17 has a liquid crystal display 32, lamps such as a vehicle detection lamp 33, an alarm generation lamp 34, and a stationary object detection lamp 3.
5. Buttons: power button 31, volume button 3
6, a switching button 37, an adjustment button 38, a selection button 39, and the like.

An example of the operation of the driver display 17 will now be described. When the vehicle detection lamp 33 detects the preceding vehicle traveling forward, the vehicle detection lamp 33 is turned on regardless of the traveling lane. When the liquid crystal display unit 32 detects a preceding vehicle traveling in the own lane in the own lane, the liquid crystal display unit 32 displays the inter-vehicle distance.

On the other hand, the warning lamp 34 is
In other words, depending on the distance between the vehicle and the preceding vehicle to be alerted,
The warning lamp lights up in three stages. Here, the respective alarm stages are referred to as primary, secondary, and tertiary alarms, and the tertiary alarm is the case where the inter-vehicle distance is the shortest and therefore the degree of danger is large.

The volume button 36 is a button for adjusting the volume of the alarm sound or the operation confirmation sound in a stepwise manner. The adjustment button 38 is used to adjust the inter-vehicle distance at which an alarm is generated in a plurality of steps, and by adjusting the inter-vehicle distance, the alarm timing for the inter-vehicle distance is adjusted. The selection button 39 is used to switch the display content of the liquid crystal display unit 32 to, for example, a relative speed with respect to a preceding vehicle.

The switching button 37 switches on / off of the stationary object alarm. Here, the stationary object refers to a stationary vehicle or an obstacle in front, and has a relative speed whose sign is opposite to that of the own vehicle speed. When the stationary object alarm is on, if a stationary object is detected in the alarm area on the own lane, the stationary object detection lamp 35 is turned on.

Next, an alarm generation algorithm in the present apparatus will be described. FIG. 3 shows a basic alarm curve, in which the vertical axis indicates the distance at the time of alarm generation and the horizontal axis indicates the relative speed with respect to the preceding vehicle. Then, an alarm is generated when the measured relative speed to the preceding vehicle and the distance between the vehicles become equal to or smaller than the alarm curve.

Here, the relative speed between the own vehicle and the preceding vehicle is compared, and the speed is divided into the following five regions according to the magnitude. In other words, it is classified into the area of approaching vehicle, following vehicle, separating vehicle, stationary object (stopped vehicle or obstacle) and oncoming vehicle. Then, an alarm is generated (or no alarm is issued) at different alarm timings in the respective areas.

[0028] be defined form using alarm curve equation some parameters (the relative speed between the host vehicle speed as shown in FIG. 3 v _h and the preceding vehicle velocity v _f (v _f -v _h), etc.) By using the adjustment button 37, the distance can be changed to a distance or near distance warning inter-vehicle distance. By setting different adjustment parameters for each of the above-mentioned alarm stages that change in the three stages, the alarm inter-vehicle distance can be changed as shown in FIG. Further, by pressing the adjustment button 38, these setting parameters change the whole, and the warning inter-vehicle distance can be set to a long distance or a short distance as a whole.

These warning logics are incorporated in the inter-vehicle distance warning device 1 and are realized by the arithmetic unit functions 14 and 15. Basically, the occurrence of an alarm is determined by whether or not the vehicle enters an alarm area defined by an alarm curve.
However, continuing to sound constantly even in the alarm area not only gives the driver a sense of incongruity, but also causes the driver to get used to it. May become unaware. For this reason, it is necessary to suppress alarms under certain conditions, reduce the number of alarms, and generate alarms only when really necessary.

Next, the alarm suppression condition will be described with reference to FIGS.

FIG. 5 shows an example in which the vehicle speed is divided into a plurality of regions and different alarm suppression conditions are set in each region. In FIG. 5, the vehicle speed is set in a low speed range (v _h <
V ₀ ) and a high-speed range (v _h > V ₀ ) are shown, and the condition for suppressing the alarm is switched between the condition of suppressing and not the condition depending on the relative speed of the brake and the preceding vehicle.

[0032] shows the difference of suppressing conditions relative to the brake Roh turned on and off in the vehicle speed V ₀ and less than greater than or equal _to V _0. That is, when the relative speed is less than 0, that is, in the approaching state, the alarm suppression by the brake operation when the tertiary alarm occurs is changed between a low speed (v _h <V ₀ ) and a high speed (v _h ≧ V ₀ ). I have.
Under low-speed conditions below the vehicle speed V _0, alarm suppression is performed by brakes to prevent an alarm from sounding too much. However, under high-speed conditions above the vehicle speed V ₀ , it is assumed that there is a high danger and braking is not suppressed.

FIG. 6 shows a flowchart of the tertiary alarm suppression operation. In the following flow charts, only the part related to the suppression condition of the embodiment is extracted and shown in the entire alarm operation flow, and the part having no relation is omitted.

First, in step 101, detection of a preceding vehicle and detection of vehicle information (vehicle speed, yaw rate, etc.) by a millimeter wave radar are performed. If it is determined that there is a preceding vehicle on the own lane and the vehicle is approaching, the process proceeds to step 102, where it is determined whether the vehicle is at the third warning distance. If it is determined that the vehicle is at the tertiary warning distance, the routine proceeds to step 103, where the current vehicle speed v _h is compared with the set vehicle speed V ₀ . If vehicle speed V
If it is ₀ or more, the routine proceeds to step 106, where the tertiary alarm is turned on. On the other hand, if the vehicle speed is equal to or less than V ₀ , step 10
The routine goes to 4 where the brake ON / OFF determination is made. if,
If the brake is on, the routine proceeds to step 105 where the tertiary alarm is turned off. On the other hand, if the brake is off, a tertiary warning is output.

FIG. 7 is a diagram showing a case where an alarm is generated when an alarm stage is switched from a high-order alarm to a low-order alarm as a condition of alarm suppression.
An example is shown in which the suppression condition is changed in accordance with the elapsed time after switching. In FIG. 7, as a condition of the alarm suppression, for a low-order alarm with a low degree of danger, the alarm is suppressed for a certain period of time immediately after entering the alarm region. The case where an alarm is generated is shown.

That is, a timing chart is shown in the case where the vehicle moves to the secondary warning area after the tertiary warning is generated and the secondary warning is generated after the elapse of Ts seconds. This is also to eliminate the driver's familiarity due to the sounding of the secondary alarm.

FIG. 8 shows a flowchart of the secondary alarm suppressing operation.

First, in step 201, detection of a preceding vehicle and detection of vehicle information (vehicle speed, yaw rate, etc.) by the millimeter wave radar are performed. If it is determined that there is a preceding vehicle on the own lane and the vehicle is approaching, the process proceeds to step 202, where it is determined whether the vehicle is within the tertiary warning distance. If it is determined that the distance is within the tertiary warning distance, the routine proceeds to step 203, where tertiary warning processing is performed. If it is determined that the vehicle is not at the tertiary warning distance, the routine proceeds to step 204, where it is determined whether the vehicle is at the secondary warning distance. 2
If it is determined that the vehicle is at the next warning distance, the process proceeds to step 205, where the elapsed time from the end of the previous tertiary warning is calculated.
If the elapsed time exceeds Ts seconds, step 2
Move to 07 and turn on the secondary alarm. On the other hand, if the time is equal to or shorter than Ts seconds, the process proceeds to step 206 and the secondary alarm is kept off.

FIG. 9 shows a case where the lower limit speed of the vehicle speed at which the stationary object alarm is forcibly activated is set under the alarm suppression condition. That is, in the same figure, since the stationary object alarm is set to OFF in the initial state, the switching button 3
As long as 7 is not operated, no alarm is issued for a stationary object even if the distance becomes shorter than the alarm generation distance. However, in a situation where the traveling speed is high, such as on an expressway, it is desirable to activate the stationary object warning regardless of the driver's operation to alert the driver. Therefore, in FIG. 9, the own vehicle speed v _h is determined, and the stationary object alarm is forcibly turned ON at a certain vehicle speed V _S or higher.
The case where it is set so that it becomes is shown. First, in step 301, detection of a preceding vehicle and detection of vehicle information (vehicle speed, yaw rate, etc.) by the millimeter wave radar are performed. If it is determined that there is a preceding vehicle on the own lane and the vehicle is approaching, the process proceeds to step 302 to check whether the stationary object warning is off. When the stationary object warning is determined to be off-state, the sequence proceeds to step 303, to compare the vehicle speed v _h and the set vehicle speed V _S. If the own vehicle speed exceeds the set vehicle speed V _S , the process proceeds to step 305, where the vehicle shifts to a stationary object alarm compulsory ON state. In this case, if the stationary object target exists and is in the alarm area, the stationary object alarm is generated even if the switch button for setting the stationary object alarm off is set.

FIG. 10 is a flowchart showing a case where an alarm is generated when the distance between the vehicles becomes equal to or less than a predetermined distance, regardless of whether the stationary object alarm is on or off. The initial off of the stationary object alarm is based on the current sensor's ability to recognize and distinguish between objects that should be alerted, such as stopped vehicles on their own lane, and objects that should not be alerted, such as roadside signs and viaducts, from a long distance. It is set to prevent false alarm increase. However, if the distance becomes a certain distance or less, it becomes easy to determine whether the vehicle is a stopped vehicle or a roadside object on the own lane. Therefore, an alarm is generated when the distance becomes equal to or less than the set distance Ds.

First, in step 401, detection of a preceding vehicle and detection of vehicle information (vehicle speed, yaw rate, etc.) by a millimeter wave radar are performed. If it is determined that there is a preceding vehicle on the own lane and the vehicle is approaching, the process proceeds to step 402, where it is determined whether the stationary object alarm is off. If the stationary object alarm is ON, the process proceeds to step 405, and an alarm is generated for a target at a first to third order alarm distance for a stationary object (step 406).

On the other hand, if the stationary object alarm is off, the routine proceeds to step 403, where the inter-vehicle distance d and the set distance Ds are compared in magnitude. If d <Ds, a stationary object alarm is generated (step 407).

[0043]

As described above, according to the present invention, even when the inter-vehicle distance between the host vehicle and the preceding vehicle satisfies the alarm condition, the alarm condition is set so that the alarm is not frequently generated. From this, it is possible to provide an inter-vehicle distance alarm device and a method thereof that can suppress the number of times of alarm generation and appropriately and effectively call attention to a driver.

[Brief description of the drawings]

FIG. 1 is a diagram showing an inter-vehicle distance warning device 1 which is a system to which the present invention is applied.

FIG. 2 is a diagram showing an example of a driver display 17 which is an alarm display.

FIG. 3 is a diagram showing an alarm curve.

FIG. 4 is a diagram for explaining changing a warning inter-vehicle distance;

FIG. 5 is a diagram showing an example of a case where different alarm suppression conditions are set in each region of the vehicle speed.

FIG. 6 is a flowchart of a tertiary alarm suppression operation.

FIG. 7 is a diagram illustrating an example of a case where an alarm generation / suppression condition is changed according to an elapsed time.

FIG. 8 is a flowchart of a secondary alarm suppression operation.

FIG. 9 is a diagram showing a case where a lower limit speed of the vehicle speed at which a stationary object alarm is forcibly activated is set.

FIG. 10 is a flowchart in a case where an alarm is issued when the distance becomes equal to or less than a certain inter-vehicle distance.

[Explanation of symbols]

1 ... inter-vehicle distance warning system, 2 ... own car, 3 ... preceding car, 4
... Antenna unit, 5 ... Vehicle distance / relative speed / angle measurement, 6 ... Angular speed sensor, 7 ... Angular speed, 10 ... Lane judgment
11: preceding vehicle judgment, 12: stationary object judgment, 13: alarm judgment algorithm, 14: alarm judgment, 15: alarm instruction, 17
…… Driver display, 26… Vehicle speed signal / brake signal.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI theme coat ゛ (Reference) B60R 21/00 B60R 21/00 626D 626F G08B 21/00 G08B 21/00 H (72) Inventor Kazuhiko Hanawa Ibaraki Hitachi, Ltd.Automotive Equipment Group, Hitachi Ltd., Hitachi, Ltd. Automotive Equipment Group (7220) Fumihiko Okai, Hitachi, Ltd., Hitachi, Ltd., Hitachi, Ltd.Automotive Equipment Group 2520, Hitachi, Ltd.Automotive Equipment Group (72) Inventor, Kikuo Suzuki, Kanagawa, Japan 3-25-1 Tonomachi, Kawasaki-ku, Kawasaki-ku, Japan Isuzu Motor Co., Ltd. (72) Inventor Tatsuya Yamada 8 Tsurana, Fujisawa-shi, Kanagawa Isuzu Motors, Inc. F-term (reference) 5C086 AA52 BA22 CA25 CB27 DA01 DA08 5H180 AA01 CC12 LL01 LL04 LL07 LL08

Claims (8)

[Claims] 1. A sensor for detecting the distance, relative speed, and azimuth angle of a warning object, which is a preceding vehicle or an obstacle, when the object is too close to the warning object in its own lane. The inter-vehicle distance warning device notifies the driver of the danger state by at least one of a warning sound and a lamp lighting, according to the speed of the own vehicle. An inter-vehicle distance alarm device characterized in that, when an alarm suppression condition determined by a speed is met, a setting can be made so as to inhibit an alarm even within an alarm generation distance. 2. The inter-vehicle distance alarm device according to claim 1, wherein the own vehicle speed is divided into a plurality of regions, and different alarm suppression conditions are set in each region. 3. The inter-vehicle distance warning device according to claim 1, wherein a plurality of warning stages are set for the warning suppression condition in accordance with a degree of danger. 4. The inter-vehicle vehicle according to claim 3, wherein when the alarm stage is switched from a higher-order alarm to a lower-order alarm, the alarm suppression condition is changed according to an elapsed time after the switching. Distance alarm device. 5. The inter-vehicle distance according to claim 1, wherein when the object to be alerted is a stationary object, an alarm for a stationary object can be set to be suppressed separately from the alarm suppression condition. Alarm device. 6. The inter-vehicle distance according to claim 5, wherein even when the warning for the stationary object is set to be suppressed, the lower limit speed of the vehicle speed at which the warning is forcibly activated is set. Alarm device. 7. An inter-vehicle distance alarm device according to claim 5, wherein an alarm is issued when the distance becomes less than a predetermined inter-vehicle distance, even when the alarm for the stationary object is set to be suppressed. 8. A method for detecting a distance, a relative speed, and an azimuth angle of a warning object, which is a preceding vehicle or an obstacle, using a measurement sensor capable of detecting the distance, when the warning object in the own lane is approached too much. In accordance with the vehicle distance warning method for notifying the driver of the danger condition by at least one of a warning sound and a lamp lighting, the presence or absence of a brake operation of the own vehicle based on the own vehicle speed, or the relative to the warning object An inter-vehicle distance warning method comprising: when a warning suppression condition determined by a speed is met, the warning is suppressed even within the warning generation distance, and an alarm is issued when the condition is not met.