JP4221166B2 - Inter-vehicle distance alarm device and method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an inter-vehicle distance alarm device and a method thereof that issue an alarm and prompt a driver to perform an avoidance operation when the vehicle approaches a vehicle ahead or an alarm target object that is an obstacle during traveling.
[0002]
[Prior art]
The inter-vehicle distance alarm device, for example, as described in Japanese Patent Application Laid-Open No. 11-66496, has detected that the distance from the preceding vehicle or an alarm target object that is an obstacle is detected by some distance measuring sensor and is too close. It is a device that sometimes alerts the driver by generating an alarm sound or turning on an alarm lamp. In addition, there is one using a laser radar as a distance measuring sensor.
[0003]
However, in the device described in Japanese Patent Application Laid-Open No. 11-66496, an alarm is issued when the vehicle approaches an alarm target object that is a front vehicle or an obstacle and meets the conditions for issuing an alarm. Not only will it give you a sense of incongruity, but it will also cause you to get used to, and even if the alarm sounds in a situation that really requires an alarm, the driver may become unaware of the alarm.
[0004]
In order to solve this problem, Japanese Patent No. 3113702 discloses that, for example, a warning is stopped during a period when the driver of the own vehicle performs a deceleration operation and a predetermined period thereafter. .
[0005]
[Problems to be solved by the invention]
However, the one described in Japanese Patent No. 3113702 does not stop issuing a warning by setting a predetermined condition based on the speed of the host vehicle.
[0006]
When approaching the preceding vehicle or an alarm target object that is an obstacle and issuing an alarm, the risk is higher when the speed of the vehicle is higher than when the speed of the host vehicle is low.
[0007]
The present invention has been made in view of the above points, and the object of the present invention is to determine the number of vehicles based on the speed of the vehicle even when the distance between the vehicle in front of the vehicle or the obstacle and the distance between the vehicle and the vehicle is in the alarm generation region. It is an object of the present invention to provide an inter-vehicle distance alarm device and method that can appropriately and effectively alert a driver by setting such a condition to suppress the generation of an alarm.
[0008]
[Means for Solving the Problems]
In order to achieve the above object, in the present invention, a measurement sensor capable of detecting the distance, relative speed, and azimuth angle with the preceding vehicle or an obstacle alarm object is used to approach the alarm object in its own lane. In the inter-vehicle distance alarm device that informs the driver of the dangerous state by at least one of an alarm sound or lamp lighting when the distance is excessive, the presence or absence of a brake operation of the own vehicle based on the own vehicle speed, or the above When the alarm suppression condition determined by the relative speed with the alarm target is met, the alarm can be set to be suppressed even within the alarm generation distance.
[0009]
In other words, the inter-vehicle distance alarm device can be set so as not to generate an alarm under certain conditions, even if the distance to the preceding vehicle or an alarm target object that is an obstacle is within the alarm generation distance. The number of alarms can be suppressed and the alarm can be sounded in situations where an alarm is really necessary. As a result, it is possible to provide an inter-vehicle distance warning device and method that can appropriately and effectively alert the driver.
[0010]
Preferably, the vehicle speed may be divided into a plurality of areas, and different alarm suppression conditions may be set in each area.
[0011]
Preferably, a plurality of alarm stages corresponding to the degree of danger are set as the alarm suppression condition. 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 an elapsed time after the switching.
[0012]
Further, preferably, when the alarm object is a stationary object, a setting may be made so as to suppress an alarm for the stationary object separately from the alarm suppression condition. And even when it is set to suppress the alarm for the stationary object, it may be possible to set the lower limit speed of the own vehicle speed for forcibly operating the alarm, or it is set to suppress the alarm for the stationary object. Even in such a case, an alarm may be generated when the distance is less than a certain distance.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of the present invention will be described based on examples shown in the drawings.
[0014]
FIG. 1 illustrates an inter-vehicle distance warning device 1 which is an application target system of the present invention. Here, a millimeter wave radar is used as a measurement sensor, a millimeter wave radar signal is emitted from the antenna unit 4 from the own vehicle 2 to the preceding vehicle 3, and an alarm is issued when the own vehicle 2 is too close to the preceding vehicle 3. The structure of the inter-vehicle distance warning device which is made to emit is shown.
[0015]
In FIG. 1, reference numerals 5, 10 to 15 constitute the function of the 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 measurement 5 of the inter-vehicle distance, relative speed and azimuth angle with the preceding vehicle 3 is executed.
[0016]
Here, a case where a millimeter wave radar is used as the measurement sensor is illustrated, but a laser radar may be used. The present invention can be applied to this device as long as the distance, relative speed, and azimuth angle between the host vehicle 2 and the preceding vehicle 3 can be obtained by measurement or calculation.
[0017]
In FIG. 1, the preceding vehicle 3 is described as an alarm target, but a stopped vehicle, a roadside sign, or an obstacle such as a viaduct can be used as the alarm target.
[0018]
Further, the angular velocity sensor 6 provided in the host vehicle 2 measures the angular velocity 7, and the curvature R of the traveling road is estimated from the measured angular velocity 7. Thereby, for example, even when the preceding vehicle is measured at the adjacent lane position during curve driving, the preceding vehicle position is corrected using the estimated radius of curvature R, and as a result, it is determined that the vehicle is in the own lane. It becomes possible.
[0019]
Based on these determinations, an alarm determination 14 is performed using the alarm determination algorithm 13, the vehicle speed signal, and the brake signal 26. Based on the alarm judgment, an alarm instruction 15 is generated, an alarm signal 16 is generated, and an alarm sound is generated, lit and / or displayed on the driver display 17.
[0020]
Here, the determination of whether the target is a moving object or a stationary object can be made by comparing the detected relative speed with the target and the vehicle speed based on the vehicle speed signal.
[0021]
FIG. 2 shows an example of the driver display 17 that is an alarm display. The driver display 17 includes a liquid crystal display 32, a vehicle detection lamp 33 as a lamp, an alarm generation lamp 34, a stationary object detection lamp 35, and a power button 31, a volume button 36, a switching button 37, an adjustment button 38 as buttons. And a selection button 39 and the like.
[0022]
An example of the operation of the driver display 17 will be described next. The vehicle detection lamp 33 is turned on regardless of the travel lane when a preceding vehicle traveling ahead is detected. Further, 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.
[0023]
On the other hand, the alarm generation lamp 34 is lit in three stages according to the distance between the vehicle in the own lane, that is, the preceding vehicle to be alarmed. Here, each alarm stage is referred to as a primary alarm, a secondary alarm, and a tertiary alarm, and the tertiary alarm is the case where the distance between the vehicles is the shortest and therefore the degree of danger is large.
[0024]
The volume button 36 is a button for adjusting the volume of an alarm sound or an operation confirmation sound in stages. The adjustment button 38 adjusts the inter-vehicle distance at which an alarm is generated in a plurality of stages. By adjusting this, 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, the relative speed with the preceding vehicle.
[0025]
The switch button 37 switches on / off of the stationary object alarm. Here, the stationary object refers to a stopped vehicle or a front obstacle, and has a relative speed whose sign is opposite to the own vehicle speed. When the stationary object alarm is ON, the stationary object detection lamp 35 is turned on when a stationary object is detected in the alarm area on the own lane.
[0026]
Next, an alarm generation algorithm in this apparatus will be described. FIG. 3 shows a basic warning curve, in which the vertical axis indicates the distance at the time of alarm occurrence and the horizontal axis indicates the relative speed with the preceding vehicle. Then, an alarm is generated when the measured relative speed and the inter-vehicle distance are below the alarm curve.
[0027]
Here, the relative speed between the own vehicle speed and the preceding vehicle is compared and divided into the following five areas according to the magnitude. That is,
(1) Approaching vehicle (2) Separation following vehicle (3) Separation vehicle (4) Stationary object (stopped vehicle or obstacle)
(5) Classified as oncoming vehicles. Then, alarms are generated (or not alarmed) at different alarm timings in the respective areas.
[0028]
The warning curve calculation formula can be defined by using several parameters (such as the relative speed (v _f −v _h ) of the own vehicle speed v _h and the preceding vehicle speed v _f as shown in FIG. 3). The button 37 can change the distance between the far and near warning inter-vehicle distances. With respect to each of the warning stages that change in the above-described three stages, it is possible to change the warning inter-vehicle distance as shown in FIG. 4 by setting different adjustment parameters. Further, by pressing the adjustment button 38, these setting parameters are changed as a whole, and the distance between the warning vehicles can be set as far or near as a whole.
[0029]
These alarm logics are built in the inter-vehicle distance alarm device 1 and are realized in the arithmetic unit functions 14 and 15. Basically, the occurrence of an alarm is determined by whether or not it has entered a warning area determined by an alarm curve. However, even if it is in the alarm area, it will not only give the driver a sense of incongruity, but it will also result in getting used to the driver, and the driver will be dangerous even if the alarm sounds in a situation that really requires an alarm. May become unconscious. For this reason, it is necessary to suppress alarms under certain conditions to reduce the number of alarms and to generate alarms only when necessary.
[0030]
Next, alarm suppression conditions will be described with reference to FIGS.
[0031]
FIG. 5 shows an example in which the own vehicle speed is divided into a plurality of areas and different alarm suppression conditions are set in each area. In FIG. 5, the host vehicle speed is divided into two regions, a low speed region (v _h <V ₀ ) and a high speed region (v _h > V ₀ ), and the alarm suppression condition is suppressed by the relative speed between the brake and the preceding vehicle.・ It shows the case of switching the condition of not.
[0032]
It shows the difference in the restraint condition with respect to the brake Roh on and off at 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 third alarm is generated is changed between the low speed (v _h <V ₀ ) and the high speed (v _h ≧ V ₀ ). Yes. In the low speed condition below the vehicle speed V ₀ , the alarm is suppressed by the brake in order to prevent the alarm from sounding excessively. However, in the high speed condition at the vehicle speed V ₀ or higher, the danger is high and the brake is not suppressed even if the brake is applied.
[0033]
FIG. 6 shows a flowchart of the tertiary alarm suppression operation. In the subsequent flowcharts, only the portion related to the suppression condition of the embodiment is extracted and shown in the entire alarm operation flow, and the unrelated portions are omitted.
[0034]
First, in step 101, preceding vehicle detection and vehicle information (vehicle speed, yaw rate, etc.) are detected by millimeter wave radar. If it is determined that there is a preceding vehicle on the own lane and that the vehicle is approaching, the process proceeds to step 102 where it is determined whether the vehicle is within the tertiary warning distance. If it is determined that the distance is the tertiary warning distance, the process proceeds to step 103, and the current vehicle speed v _h is compared with the set vehicle speed V ₀ . If the vehicle speed is equal to or higher than V ₀ , the process proceeds to step 106 where the tertiary alarm is turned on. On the other hand, if the vehicle speed is equal to or lower than V ₀ , the routine proceeds to step 104 where a brake on / off determination is made. If the brake is on, the routine proceeds to step 105 and the tertiary alarm is turned off. On the other hand, if the brake is off, a tertiary alarm is output.
[0035]
FIG. 7 shows an example of a case where the alarm suppression condition is changed according to the elapsed time after the alarm generation / suppression condition is changed when the alarm stage is switched from a higher order alarm to a lower order alarm. ing. In FIG. 7, as a condition for 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 area. The case where an alarm is generated is shown.
[0036]
That is, the timing diagram in the case where the secondary alarm is generated after the vehicle has moved to the secondary alarm area after Ts seconds have elapsed after the tertiary alarm is generated is shown. This is also to eliminate the driver's habituation due to excessive secondary alarms.
[0037]
FIG. 8 shows a flowchart of the secondary alarm suppression operation.
[0038]
First, in step 201, preceding vehicle detection and vehicle information (vehicle speed, yaw rate, etc.) are detected by millimeter wave radar. If it is determined that there is a preceding vehicle on the own lane and the vehicle is in the approaching state, 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 the tertiary alarm distance, the process proceeds to step 203 to perform the tertiary alarm process. If it is determined that the distance is not within the tertiary alarm distance, the process proceeds to step 204 to determine whether the distance is in the secondary alarm distance. If it is determined that the distance is in the secondary alarm distance, the process proceeds to step 205, and the elapsed time from the end of the previous tertiary alarm is calculated. If the elapsed time exceeds Ts seconds, the process proceeds to step 207 and the secondary alarm is turned on. 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.
[0039]
FIG. 9 shows a case where the lower limit speed of the own vehicle speed for forcibly operating the stationary object alarm is set under the alarm suppression condition. That is, in the figure, since the stationary object alarm is set to OFF in the initial state, the stationary object is not alarmed even if the distance is less than the alarm generation distance unless the switch button 37 is operated. However, in situations where the traveling speed is high, such as on an expressway, it is desirable to raise a stationary object alarm to alert the driver regardless of the driver's operation. Therefore, FIG. 9 shows a case where the host vehicle speed v _h is determined and the stationary object alarm is forcibly set to ON at a certain vehicle speed V _S or higher. First, in step 301, preceding vehicle detection and vehicle information (vehicle speed, yaw rate, etc.) are detected by millimeter wave radar. 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 alarm is off. If it is determined that the stationary object warning is in the off state, the process proceeds to step 303, where the own vehicle speed v _h is compared with the set vehicle speed V _S. If the host vehicle speed exceeds the set vehicle speed V _S , the process proceeds to step 305, and the stationary object alarm is forced on. In this case, if a stationary object target exists and is in the alarm area, a stationary object alarm is generated even if the switch button is set to turn off the stationary object alarm.
[0040]
FIG. 10 shows a flowchart for generating an alarm when the distance between the vehicles is below a certain distance regardless of whether the stationary object alarm is on or off. The initial off of stationary object warning is based on the current sensor ability, and recognizes objects that should originally be alarmed, such as stopped vehicles on the own lane, and objects that should not be alarmed, such as roadside signs and viaducts, from a distance. It is set to prevent false alarms from increasing. However, if the distance is less than a certain distance, it is easy to determine whether the vehicle is a stop vehicle on the own lane or a roadside object. Therefore, an alarm is generated when the distance becomes less than the set distance Ds.
[0041]
First, in step 401, detection of a preceding vehicle and detection of vehicle information (vehicle speed, yaw rate, etc.) by 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 to determine 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 the target at the primary to tertiary alarm distance for the stationary object (step 406).
[0042]
On the other hand, if the stationary object alarm is off, the process proceeds to step 403, where the inter-vehicle distance d is compared with the set distance Ds. If d <Ds, a stationary object alarm is generated (step 407).
[0043]
【The invention's effect】
As described above, in the present invention, even when the distance between the host vehicle and the preceding vehicle satisfies the alarm condition, the suppression condition is provided so that the alarm is not frequently generated. Therefore, it is possible to provide an inter-vehicle distance alarm device and method that can suppress the number of alarms and promptly and effectively alert the driver.
[Brief description of the drawings]
FIG. 1 is a diagram showing an inter-vehicle distance alarm 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 that is an alarm display.
FIG. 3 is a diagram showing an alarm curve.
FIG. 4 is a diagram for explaining changing an alarm inter-vehicle distance.
FIG. 5 is a diagram showing an example when different alarm suppression conditions are set in each area of the host vehicle speed.
FIG. 6 is a flowchart of a tertiary alarm suppression operation.
FIG. 7 is a diagram illustrating an example of changing an alarm generation / suppression condition according to an elapsed time.
FIG. 8 is a flowchart of a secondary alarm suppression operation.
FIG. 9 is a diagram illustrating a case where a lower limit speed of the own vehicle speed for forcibly operating a stationary object alarm is set.
FIG. 10 is a flowchart in the case of generating an alarm when the distance between vehicles becomes equal to or less than a certain distance.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Inter-vehicle distance warning system, 2 ... Own vehicle, 3 ... Preceding vehicle, 4 ... Antenna unit, 5 ... Inter-vehicle distance / relative speed / angle measurement, 6 ... Angular velocity sensor, 7 ... Angular velocity, 10 ... Lane judgment, 11 ... Preceding Car judgment, 12 ... stationary object judgment, 13 ... warning judgment algorithm, 14 ... warning judgment, 15 ... warning instruction, 17 ... driver display, 26 ... vehicle speed signal / brake signal.

Claims (7)

Using a measuring sensor that can detect the distance, relative speed, and azimuth angle with the preceding vehicle or an alarm target that is an obstacle, depending on the distance and relative speed when the alarm target in the lane is too close Informing the driver according to the alarm level set in stages according to the degree of danger by at least one of alarm sound or lamp lighting ,
When the predetermined alarm suppression condition set for each alarm stage is met, the alarm is set to be suppressed even within the alarm generation distance, and at least as the alarm suppression condition, the distance is short and the degree of danger is large. An inter-vehicle distance alarm device that is set as a condition when the host vehicle speed is equal to or lower than a predetermined level and a brake operation of the host vehicle is performed at a predetermined or higher alarm level . The inter-vehicle distance alarm device according to claim 1, wherein the own vehicle speed is divided into a plurality of areas, and different alarm suppression conditions are set in each area. When the alarm stage is switched from a higher order alarm to a lower order alarm, the alarm suppression condition is set so as not to output the lower order alarm while the elapsed time after the switching is a predetermined time or less. Item 1. The inter-vehicle distance alarm device according to Item 1 . The inter-vehicle distance alarm device according to claim 1 , wherein when the alarm object is a stationary object, a setting is made so as to suppress an alarm for the stationary object separately from the alarm suppression condition. The inter-vehicle distance alarm device according to claim 4, wherein a lower limit speed of the own vehicle speed that forcibly activates the alarm is set even when the alarm for the stationary object is set to be suppressed. The inter-vehicle distance alarm device according to claim 4, wherein even when the alarm for the stationary object is set to be suppressed, an alarm is generated when the distance is less than a certain inter-vehicle distance. Using a measuring sensor that can detect the distance, relative speed, and azimuth angle with the preceding vehicle or an alarm target that is an obstacle, depending on the distance and relative speed when the alarm target in the lane is too close Informing the driver according to the alarm level set in stages according to the degree of danger by at least one of alarm sound or lamp lighting ,
When the predetermined alarm suppression condition set for each alarm stage is met, the alarm is set to be suppressed even within the alarm generation distance, and at least as the alarm suppression condition, the distance is short and the degree of danger is large. An inter-vehicle distance warning method that is set as a condition when the host vehicle speed is equal to or lower than a predetermined level and a brake operation of the host vehicle is performed in a higher-order alarm stage than a predetermined level .

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