JPH07302399A - Alarm device for distance between vehicles - Google Patents

Abstract

PURPOSE:To improve the comfortableness of driving and the safety of traveling by avoiding the generation of an excess alarm to a driver. CONSTITUTION:When the distance from one's own vehicle (A) up to a front object is shorter than a prescribed distance determined in accordance with the speed of the vehicle (A) detected by a vehicle speed detecting means 101 after stopping the generation of an alarm by an alarm stopping means 111, a speed reducing operation detecting means 109 detects operation for reducing the speed of the vehicle (A), and when the relation between the front object and the vehicle (A) is in a prescribed state, an alarm generation control means 113 allows an alarming means 107 to generate an alarm.

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 that gives an alarm when the inter-vehicle distance from the host vehicle to the front is not the inter-vehicle distance required for safe driving by measuring the inter-vehicle distance with a radar device of an automobile. Regarding the alarm device.

[0002]

2. Description of the Related Art A conventional vehicle-to-vehicle distance warning device detects a vehicle-to-vehicle distance to a vehicle ahead by a distance detecting means such as a pulse laser light system, and further calculates a warning vehicle-to-vehicle distance according to a predetermined calculation method. The distance is compared with the actual inter-vehicle distance detected by the distance detecting means. From this comparison, when the actual inter-vehicle distance is shorter than the warning inter-vehicle distance, that is, when the so-called warning condition is satisfied, the inter-vehicle distance warning device provides the driver with a sufficient inter-vehicle distance for safe driving by means such as voice. A warning indicating that the vehicle is not maintained is issued, and, for example, an alarm sound is emitted to maintain the vehicle distance required for safe driving.

Further, as a conventional inter-vehicle distance warning device,
It is disclosed in Japanese Utility Model Publication No. 2-43746. According to Japanese Utility Model Application Laid-Open No. 2-43746, driving is performed when a driver performs a deceleration operation such as releasing an accelerator pedal (hereinafter, referred to as accelerator off) after a so-called alarm condition is satisfied and an alarm is issued. It is assumed that the person recognizes the approach to the vehicle ahead and stops the warning, thereby preventing an excessive warning.

[0004]

However, according to Japanese Utility Model Laid-Open No. 2-43746, after the warning is stopped by the accelerator being turned off by the driver, for example, the own vehicle is traveling with the accelerator off. In some cases, a vehicle ahead may perform a braking operation, and the inter-vehicle distance may be rapidly reduced, and a so-called alarm condition may be satisfied. Also,
According to Japanese Utility Model Laid-Open No. 2-43746, when the vehicle is traveling on a long downhill or the like with the accelerator off, the driver may gradually approach the vehicle ahead without being aware of it and the alarm condition may be satisfied. is there. In this case, actual Kaihei 2-43746
Since it is difficult to issue an inter-vehicle distance warning at an appropriate timing in the gazette, there has been a request for improvement from the past.

The present invention has been made in view of such conventional problems, and an object thereof is to avoid excessive warning to the driver to improve the driving comfort and to improve the driving comfort after the warning is stopped. When the distance from the vehicle to the target in front is shorter than the predetermined distance determined according to the vehicle speed of the host vehicle, an alarm is generated again to improve driving comfort and driving safety. It is to provide a distance warning device.

[0006]

In order to achieve the above object, as shown in the claim correspondence diagram of FIG. 1, the first invention according to claim 1 is a vehicle speed detecting means 101 for detecting the vehicle speed of the host vehicle. The distance detection means 103 for detecting the distance from the host vehicle to the front target object, the distance from the host vehicle to the front target object detected by the distance detection means 103, and the host vehicle detected by the vehicle speed detection means 101. The comparing means 105 for comparing a predetermined distance determined according to the vehicle speed, and the distance from the own vehicle to the front target object by the comparing means 105 according to the vehicle speed of the own vehicle detected by the vehicle speed detecting means 101. An alarm means 107 for issuing an alarm when the distance is shorter than a predetermined distance, and a distance from the own vehicle to a front target object by the comparing means 105 is the vehicle speed detecting means 101.
And a deceleration operation detecting means 109 for detecting whether or not an operation for decelerating the own vehicle is performed when the distance is shorter than a predetermined distance determined according to the vehicle speed of the own vehicle detected by the deceleration operation detecting means 109. In an inter-vehicle distance warning device comprising an alarm stop means 111 for stopping the alarm by the alarm means 107 when an operation of decelerating the own vehicle is detected, after the alarm is stopped by the alarm stop means 111, the front Warning control means 11 for giving a warning by the warning means when the target and the own vehicle are in a predetermined situation.
The point is to have 3 and.

According to a second aspect of the present invention, a relative speed difference for calculating a relative speed difference between the own vehicle and a front target from the amount of change in the distance detected by the distance detecting means 103 within a unit time. The alarm control means 1 is provided with a computing means.
The case where the front target and the own vehicle in 13 are in a predetermined situation is summarized in that the relative speed difference calculated by the relative speed difference calculating means 115 is a predetermined value or more.

According to a third aspect of the present invention, a relative speed difference for calculating a relative speed difference between the host vehicle and a front target from the amount of change in the distance detected by the distance detecting means 103 within a unit time. When the target in front of the alarm control means 113 and the own vehicle are in a predetermined state, the change in the relative speed difference calculated by the relative speed difference calculation means 115 within a unit time is provided. The relative acceleration between the host vehicle and the front target is calculated from the amount, and when the relative acceleration is equal to or more than a predetermined value, and the distance detected by the distance detecting means 103 is equal to or more than the distance at which the alarm means 107 gives an alarm. The main point is.

According to a fourth aspect of the present invention, a relative speed difference for calculating a relative speed difference between the host vehicle and a front target from the amount of change in the distance detected by the distance detecting means 103 within a unit time. When the target object in front of the alarm control means 113 and the host vehicle are in a predetermined state, the alarm stop means 107 stops the alarm, and the deceleration operation detection means 109 detects deceleration. The time measured by the time measuring means 117 for measuring the time from the time is a predetermined time or more, and the relative speed difference calculating means 11
The gist is that the relative speed difference calculated by 5 is equal to or greater than a predetermined value.

[0010]

According to the first aspect of the present invention, the distance from the vehicle to the front target is detected by the deceleration operation detecting means 109 according to the vehicle speed of the vehicle detected by the vehicle speed detecting means 101. When the distance is shorter than the predetermined distance, the operation of decelerating the host vehicle is deceleration operation detecting means 109.
When the alarm is detected by the alarm stop means 111, the alarm by the alarm means 107 is stopped. After the alarm is stopped, if the target object ahead of the own vehicle is in a predetermined state, the alarm control means 113 issues an alarm again, so that an excessive alarm to the driver is avoided and driving comfort is improved. If the distance from the vehicle to the front target is shorter than the predetermined distance determined according to the vehicle speed of the vehicle after the warning is stopped, the alarm is reissued to improve driving comfort and driving. The safety of can be improved.

According to a second aspect of the invention, from the amount of change in the distance detected by the distance detecting means 103 within a unit time,
The relative speed difference calculation means 115 for calculating the relative speed difference between the own vehicle and the front target object is provided, and the relative speed difference is obtained when the front target object of the alarm control means 113 and the own vehicle are in a predetermined situation. This is a case where the relative speed difference calculated by the calculation means 115 is equal to or greater than a predetermined value, and the proximity state between the host vehicle and the target in front of the vehicle is confirmed from the relative speed difference, and an appropriate warning is given to ensure comfort and driving. The safety can be improved.

According to a third aspect of the invention, from the amount of change in the distance detected by the distance detecting means 103 within a unit time,
A relative speed difference calculating means for calculating a relative speed difference between the own vehicle and the front target, and the relative speed difference when the target in front of the alarm control means 113 and the own vehicle are in a predetermined situation. The relative acceleration with respect to the front target is calculated from the amount of change in the value of the relative speed difference calculated by the calculating means 115 within a unit time, and when the relative acceleration is equal to or more than a predetermined value, the distance detecting means 103 This is the case where the value of the detected distance is equal to or greater than the warning inter-vehicle distance at which the warning by the warning means 107 is issued, and the proximity state between the own vehicle and the target in front is confirmed, and the warning is appropriately given and the comfort of driving and Driving safety can be improved.

A fourth aspect of the present invention is based on the change amount of the distance detected by the distance detecting means 103 within a unit time,
The alarm control means 113 is provided with a relative speed difference calculating means for calculating a relative speed difference between the own vehicle and the front target, and the alarm stopping means 111 is used when the front target of the alarm control means 113 and the own vehicle are in a predetermined situation. After the alarm is stopped by the
The time measured by the time measuring means 117 for measuring the time from the detection of the deceleration operation by 9 is a predetermined time or more, and the relative speed difference calculated by the relative speed difference calculating means 115 is a predetermined value or more. Therefore, the proximity state between the host vehicle and the target in front of the vehicle can be confirmed, and an appropriate warning can be given to improve driving comfort and driving safety.

[0014]

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

FIG. 2 is a block diagram showing an embodiment of the inter-vehicle distance warning device of the present invention.

The inter-vehicle distance warning device includes an inter-vehicle distance sensor 1, a vehicle speed sensor 3, an engine idle determination switch 5,
A CPU 7, a memory unit 9 and an alarm buzzer 11 are provided. The inter-vehicle distance sensor 1 detects the inter-vehicle distance from the host vehicle to the preceding vehicle (preceding vehicle). As an example, there is a laser light or ultrasonic pulse transmission type distance sensor that has been often used in the past, but the present invention is not limited to this, and a passive triangulation type distance sensor or the like may be used as long as it detects a distance. Good. The vehicle speed sensor 3 detects the speed of the host vehicle. The engine idle determination switch 5 determines whether the engine is idling.

The CPU 7 includes an inter-vehicle distance calculating section 13, a relative speed difference calculating section 15, a relative acceleration calculating section 17, and a judging section 1.
9. An alarm ON / OFF determination unit 21 and a timer 23 are provided. The inter-vehicle distance calculation unit 13 calculates the inter-vehicle distance based on the signal input from the inter-vehicle distance sensor 1. The relative speed difference calculation unit 15 calculates the relative speed difference from the amount of change in the inter-vehicle distance value calculated by the inter-vehicle distance calculation unit 13 within a unit time. The relative acceleration calculator 17 calculates the relative acceleration from the amount of change in the relative speed difference calculated by the relative speed difference calculator 15 within a unit time. The determination unit 19 determines that the inter-vehicle distance to the preceding vehicle (preceding vehicle) is shorter than the predetermined distance determined according to the vehicle speed of the host vehicle based on the current inter-vehicle distance value, the relative speed difference, the vehicle speed value of the host vehicle, and the like. Or not. Here, the predetermined distance is an inter-vehicle distance to a vehicle in front, which is necessary for the own vehicle to safely travel during the current traveling. Further, the determination unit 19 compares the current inter-vehicle distance with the warning inter-vehicle distance calculated from the current vehicle speed and relative speed difference to determine whether the inter-vehicle distance with the vehicle in front is appropriate. Make a decision. The alarm ON / OFF determination unit 21 is based on the determination result of the determination unit 19, the signal from the engine idle determination switch 5, and the calculation results of the inter-vehicle distance calculation unit 13, the relative speed difference calculation unit 15, and the relative acceleration calculation unit 17. , It is determined whether or not the alarm is issued from the alarm buzzer 11. The timer 23 measures the elapsed time from the start of detection of the idle state of the engine idle determination switch 5 after the occurrence of the inter-vehicle distance warning. The memory unit 9 stores distance data, a warning flag (not shown), a warning prohibition flag (not shown), and the like. The alarm buzzer 11 issues an alarm based on the determination by the alarm ON / OFF determination unit 21 of the CPU 7.

The relative acceleration calculator 15 in the first and third embodiments shown below and the timer 23 in the first and second embodiments will not be included as elements in the device configuration. I do not care.

Next, the operation of the first embodiment will be described with reference to the flow charts of FIGS. 3 and 4.

First, when the power is turned on, the CPU 7 resets the warning flag to 0 as an initial operation (S1) and also resets the warning prohibition flag to 0 (S2).
Subsequently, the detection of the inter-vehicle distance is started, but in the present embodiment, the inter-vehicle distance sensor 1 of the pulse laser transmission system is used to detect the inter-vehicle distance. From the light emitter (not shown), a predetermined distance (δt: 1 m, for example)
A laser beam having a predetermined pulse width (for example, 50 nsec) is transmitted in sec. When a vehicle or the like exists ahead, the pulsed laser light is reflected and received by a light receiver (not shown) in the inter-vehicle distance sensor 1. After receiving the light, CPU7
The inter-vehicle distance calculating unit 13 measures the time from the emission of the laser beam to the reception of the laser beam, calculates the inter-vehicle distance Dp from that time to the preceding vehicle (S3), and the relative speed difference calculating unit 1
5 and the determination unit 19. The sent data of the inter-vehicle distance Dp is stored in the memory unit 9 (S4). The relative speed difference calculation unit 17 uses the following measured inter-vehicle distance data (D (t)), the previous measured data (D (t-? T): stored in S4), and the pulse emission interval value (? T) to detect the preceding vehicle. The relative speed difference Vr ((D (t-δt) -D (t)) / δt) between the two is calculated (S5). Here, if Vr is a positive value, it means approaching the vehicle ahead, and if it is negative, it means leaving. In the inter-vehicle distance warning device according to the present invention, Vr is, for example, 1 km / h or less (S
In the case of 6), the alarm is suppressed even if the alarm condition is satisfied, that is, the alarm sound from the alarm buzzer 11 is not emitted (S7).

Next, when the speed of the host vehicle is detected by the vehicle speed sensor 3 (S8), the determination unit 19 determines the warning inter-vehicle distance Da based on the relative speed difference Vr and the value of the host vehicle speed according to a predetermined arithmetic expression. Is calculated (S9). FIG. 5 shows an example of the relationship between the warning inter-vehicle distance and the speed of the host vehicle at a typical relative speed difference. If the current inter-vehicle distance Dp is longer than the warning inter-vehicle distance Da, the determination unit 19 determines that the vehicle is traveling at an appropriate inter-vehicle distance and returns to step S1 (S10). On the other hand, when the inter-vehicle distance Dp is shorter than the warning inter-vehicle distance Da, the determining unit 19 determines that the appropriate vehicle distance is not held, and proceeds to the next step. Hereinafter, examples will be described through typical traveling situations.

First, the case where the alarm area is entered with the accelerator pedal depressed (hereinafter referred to as the idle switch-off state) will be described. In step S11, the idle switch state is checked. In this case, since the accelerator pedal is off, the step is performed.
In step 12, the alarm prohibition flag is set to 0 again, and then the process proceeds to step S13. In this state, the warning prohibition flag is 0, so the process proceeds to step S14 by the determination in S13. The alarm flag is 0 when the alarm area is first entered, and therefore the process proceeds to step S15.
In the present embodiment, as shown in FIG. 6, the condition of the alarm issuance includes a condition for the value of the approaching relative speed difference, and even if the warning condition is satisfied, the approaching relative speed difference of 4 km / h.
A hysteresis is provided so that the alarm is enabled only when the above conditions are met, and the alarm is disabled when the speed is 1 km / h or less thereafter. If the approaching relative speed difference is 4 km / h or more in step S15, the alarm is enabled. In step S17, the idle switch is off, so the process proceeds to step S18 to set the alarm flag to 1 and generate an alarm (S19). ).

On the other hand, if the approaching relative speed difference is less than 4 km / h in step S15, the warning flag is set to 0.
It is held as it is (S20) and the alarm is not issued (S22). Once the alarm is issued, step S
Returning to step 3, the same routine as above is followed. In the subsequent routine, the alarm flag is set to 1, so step S14
To step S16, the approaching relative speed difference is 1 km /
The alarm is continued until it becomes equal to or less than h (while the idle switch is off: S17 → S18 → S19). After that, this flow is repeated. When the driver releases the accelerator pedal (idle switch is turned on) after the alarm is issued for the first time, this device stops the alarm (S22), sets the alarm flag to 0 (S20), and sets the alarm prohibit flag to 1
(S21) Next, the operation after the accelerator pedal is released after the alarm is issued will be described. When the accelerator pedal is released,
The alarm is prohibited in step S22, and the process returns to step S3 (at this time, the alarm prohibition flag is 1 (S21)). After that, the flow before step S13 is as described above. In step S13, since it is determined that the warning prohibition flag is 1, the process proceeds to step S23. In this embodiment, when the approaching relative speed difference becomes 7 Km / h or more again after the alarm is prohibited by turning off the accelerator, the process proceeds to steps S18 and S19, and even if the accelerator pedal is released, The alarm is generated again as shown in 7, and then the process returns to step S3 and the same flow as described above is followed. If the approaching relative speed difference is less than 7 km / h, the process returns from step S23 to S3, and the alarm prohibition state is continued.

After the warning is issued again, the warning is continued until the approaching relative speed difference becomes 1 Km / h or less (determined in step S6). Approaching relative speed difference is 1km /
When h or less, the process moves from step S6 to S7, the alarm is stopped, and the process returns to step S1.

When the accelerator pedal is released and the idle switch is on, the alarm prohibition flag is 1, but if the driver depresses the accelerator pedal again in this state, step S11 To S1
2, the alarm prohibition flag is reset to 0, and thereafter, the normal flow when the idle switch is off (S13 → S14) is proceeded to, and the same operation as described above is performed.

Next, FIGS. 8 and 9 for the second embodiment.
This will be described with reference to the flowchart of.

Hereinafter, the same operation will be performed with respect to the steps having the same numbers as in the first embodiment.

First, when the power is turned on, the CPU 7 resets the alarm flag to 0 as an initial operation (S1) and also resets the alarm prohibition flag to 0 (S2).

A laser beam having a predetermined pulse width is emitted from a light emitter (not shown) at a predetermined interval (δt).
When a vehicle or the like exists ahead, the pulsed laser light is reflected and received by a light receiver (not shown) in the inter-vehicle distance sensor 1. After the reception, the inter-vehicle distance calculation unit 13 of the CPU 7 measures the delay time from the emission of the laser light to the reception of the laser light, calculates the inter-vehicle distance Dp from that time to the preceding vehicle (S3), and calculates the relative speed difference. It is sent to the unit 15 and the determination unit 19. The sent data of the inter-vehicle distance Dp is stored in the memory unit 9 (S4). Relative speed difference calculation unit 17
Then, from the inter-vehicle distance data (D (t)) measured this time, the previous measurement data (D (t-δt): stored in S4) and the pulse emission interval value (δt), The relative speed difference Vr ((D (t-δt) -D (t)) / δt) is calculated (S
5).

Here, if Vr is a positive value, it means approaching the vehicle ahead, and if it is negative, it means leaving. In the inter-vehicle distance alarm device according to the present invention, when Vr is, for example, 1 km / h or less (S6), the alarm is suppressed even if the alarm condition is satisfied, that is, the alarm buzzer 11 does not sound the alarm sound. (S7).

Next, when the speed of the host vehicle is detected by the vehicle speed sensor 3 (S8), the determination unit 19 determines the warning inter-vehicle distance Da from the relative speed difference Vr and the value of the host vehicle speed according to a predetermined arithmetic expression. Is calculated (S9). FIG. 5 shows an example of the relationship between the warning inter-vehicle distance and the speed of the host vehicle at a typical relative speed difference. If the current inter-vehicle distance Dp is longer than the warning inter-vehicle distance Da, the determination unit 19 determines that the vehicle is traveling at an appropriate inter-vehicle distance and returns to step S1 (S10). On the other hand, if the inter-vehicle distance Dp is shorter than the warning inter-vehicle distance Da,
It is determined that the appropriate vehicle distance is not held, and the process proceeds to the next step. Hereinafter, examples will be described through typical traveling situations.

First, the case where the alarm area is entered with the accelerator pedal depressed (hereinafter referred to as the idle switch-off state) will be described. In step S11, the idle switch state is checked. In this case, since the accelerator pedal is off, the step is performed.
In step 12, the alarm prohibition flag is set to 0 again, and then the process proceeds to step S13. In this state, the warning prohibition flag is 0, so the process proceeds to step S14 by the determination in S13. The alarm flag is 0 when the alarm area is first entered, and therefore the process proceeds to step S15.
In this embodiment as well, as in the first embodiment, as shown in FIG. 6, even if the approaching relative speed is close to the alarm generation condition, as in the first embodiment, as shown in FIG. Incorporating a condition for the value of the approaching relative speed difference into the condition, even if the warning condition is satisfied, the alarm shall be enabled only when the approaching relative speed difference becomes 4 Km / h or more, and then 1 Km / h.
Hysteresis is provided so that an alarm cannot be issued when the value becomes h or less. If the approaching relative speed difference is 4 km / h or more in step S15, the alarm is enabled and S1
In 7, the idle switch is off, so the process proceeds to step S18, the alarm flag is set to 1 and an alarm is generated (S19).

On the other hand, if the approaching relative speed difference is less than 4 km / h in step S15, the warning flag is set to 0.
It is held as it is (S20) and the alarm is not issued (S22). Once the alarm is issued, step S
Returning to step 3, the same routine as above is followed. In the subsequent routine, the alarm flag is set to 1, so step S14
To step S16, the approaching relative speed difference is 1 km /
The alarm is continued until it becomes equal to or less than h (while the idle switch is off: S17 → S18 → S19). After that, this flow is repeated. When the driver returns the accelerator pedal (idle switch is turned on) after the alarm is issued for the first time, this device stops the alarm (S22), sets the alarm flag to 0 (S20), and sets the alarm prohibit flag to 1
(S21) Next, the operation after the accelerator pedal is released will be described following the warning generation. When the accelerator pedal is released, the alarm is prohibited in step S22, and step S3
(The alarm prohibition flag is set to 1 (S21) at this time). After that, the flow before step S13 is as described above. In step S13, since it is determined that the warning prohibition flag is 1, the process proceeds to step S24. Upon proceeding to step S24, the relative acceleration calculation unit 17 determines the relative acceleration (dVr), which is the amount of change in the approaching relative velocity within a unit time.
/ Dt) is calculated. If the relative acceleration is equal to or greater than zero by the calculation, the vehicle further continues to approach the vehicle ahead, so the process proceeds to step 18 according to the determination in step 25, the alarm flag is set to 1 and the alarm is issued again ( S19), and thereafter, the process returns to step S3, and the same flow as described above is followed. On the other hand, in step S25,
When it is determined that the relative acceleration is negative, the process proceeds to step S26, and the relative approach movement distance (Vr ² / (2 | dVr / dt) until the approach relative speed difference becomes zero.
|)) And the current inter-vehicle distance Dp are compared. As a result of the comparison, when the relative approaching travel distance is longer than the inter-vehicle distance Dp, the approaching relative speed difference is small, but the distance from the host vehicle to the target ahead is set to a predetermined value determined according to the vehicle speed of the host vehicle. Since it may be shorter than the distance, step S1
In step 8, the alarm flag is changed to 1, an alarm is generated again, and the process returns to step S3 (S19).

After the alarm is issued again, the alarm is continued until the approaching relative speed difference becomes 1 Km / h or less (determined in step S6). Approaching relative speed difference is 1km /
When h or less, the process moves from step S6 to S7, the alarm is stopped, and the process returns to step S1. Step S26
In the above, when the relative approach movement distance is shorter than the inter-vehicle distance Dp, the approach relative speed does not become shorter than the predetermined distance set according to the vehicle speed of the own vehicle from the own vehicle to the target ahead. Since the difference becomes zero, the alarm is not generated again, the process directly returns to step S3, and the same flow as described above is repeated thereafter.

When the accelerator pedal is returned and the idle switch is turned on, the alarm prohibition flag is 1, but if the driver depresses the accelerator pedal again in this state, step S11 To S1
2, the alarm prohibition flag is reset to 0, and then the normal flow when the idle switch is turned off (S13 → S14) is performed, and the same operation as described above is performed.

Further, the operation of the third embodiment will be described with reference to the flow charts of FIGS. Below, the first
The same operation is performed for the steps having the same numbers as those in the embodiment.

First, when the power is turned on, the CPU 7 resets the warning flag to 0 as an initial operation (S1) and also resets the warning prohibition flag to 0 (S2).
A laser beam having a predetermined pulse width is emitted from a light emitting device (not shown) at a predetermined interval (δt). When a vehicle or the like exists ahead, the pulsed laser light is reflected and received by a light receiver (not shown) in the inter-vehicle distance sensor 1. After receiving the light, the inter-vehicle distance calculation unit 13 of the CPU 7
Measure the time from sending the laser light to receiving it,
The inter-vehicle distance Dp to the vehicle ahead from that time is calculated (S3) and sent to the relative speed difference calculation unit 15 and the determination unit 19. The sent distance data is stored in the memory unit 9 (S
4). In the relative speed difference calculation unit 17, the inter-vehicle distance data measured this time (D (t)) and the previous measurement data (D (t-δt): S4
From the pulse emission interval value (δt) and the relative speed difference Vr ((D (t-δt) -D (t)) from the vehicle ahead.
/ Δt) is calculated (S5). Here, if Vr is a positive value, it means approaching the vehicle ahead, and if it is negative, it means leaving.
In the inter-vehicle distance warning device of the present invention, Vr is, for example,
When it is 1 km / h or less (S6), the alarm is suppressed even if the alarm condition is satisfied, that is, the alarm sound from the alarm buzzer 11 is not emitted (S7).

Next, when the speed of the host vehicle is detected by the vehicle speed sensor 3 (S8), the determination unit 19 determines the warning inter-vehicle distance Da based on the relative speed difference Vr and the value of the host vehicle speed according to a predetermined arithmetic expression. Is calculated (S9). FIG. 5 shows an example of the relationship between the warning inter-vehicle distance and the speed of the host vehicle at a typical relative speed difference. If the current inter-vehicle distance Dp is longer than the warning inter-vehicle distance Da, the determination unit 19 determines that the vehicle is traveling at an appropriate inter-vehicle distance, and returns to step S1 (S10). On the other hand, if the inter-vehicle distance Dp is shorter than the warning inter-vehicle distance Da,
It is determined that the appropriate vehicle distance is not held, and the process proceeds to the next step. Hereinafter, examples will be described through typical traveling situations.

First, the case where the alarm area is entered with the accelerator pedal depressed (hereinafter referred to as the idle switch-off state) will be described. In step S11, the idle switch state is checked. In this case, since the accelerator pedal is off, the step is performed.
In step 12, the alarm prohibition flag is set to 0 again, and then the process proceeds to step S13. In this state, the warning prohibition flag is 0, so the process proceeds to step S14 by the determination in S13. The alarm flag is 0 when the alarm area is first entered, and therefore the process proceeds to step S15.

In this embodiment as well, as in the first and second embodiments, as shown in FIG. 6, the condition of the approaching relative speed difference is included in the condition of the alarm generation, and the alarm condition is satisfied. Even if the approaching relative speed difference becomes 4 km / h or more, the alarm should be enabled for the first time, and then 1 km / m.
Hysteresis is provided so that an alarm cannot be issued when the value becomes h or less. If the approaching relative speed difference is 4 km / h or more in step S15, the alarm is enabled and S1
In 7, the idle switch is off, so the process proceeds to step S18, the alarm flag is set to 1 and an alarm is generated (S19).

On the other hand, if the approaching relative speed difference is less than 4 km / h in step S15, the warning flag is set to 0.
It is held as it is (S20) and the alarm is not issued (S22). Once the alarm is issued, step S
Returning to step 3, the same routine as above is followed. In the subsequent routine, the alarm flag is set to 1, so step S14
To step S16, the approaching relative speed difference is 1 km /
The alarm is continued until it becomes equal to or less than h (while the idle switch is off: S17 → S18 → S19). After that, this flow is repeated. When the driver releases the accelerator pedal (idle switch is turned on) after the alarm is issued for the first time, this device stops the alarm (S22), sets the alarm flag to 0 (S20), and sets the alarm prohibit flag to 1
(S21).

Next, the operation after the accelerator pedal is released after the alarm is issued will be described. When the accelerator pedal is returned, the alarm is prohibited in step S22, and the process returns to step S3 (at this time, the alarm prohibition flag is 1 (S2
1)). After that, the flow before step S13 is
As described above. In step S13, since it is determined that the alarm prohibition flag is 1, the process proceeds to step S29.
When the process proceeds to step 29, the timer 23 of the CPU 7 measures the time (τ) after the idle switch is turned on. If the time τ is less than 4.3 seconds, for example, according to the determination in step S30, the process directly returns to step S3,
If it is 4.3 seconds or more, the process proceeds to step S31. Here, the time of 4.3 seconds corresponds to an engine braking state (idling state: deceleration 0.196 m) which is assumed in advance.
/ S ² ) is the time required for the approaching relative speed difference to decelerate from 4 Km / h (alarm start relative speed difference in normal flow: FIG. 6) to 1 Km / h (alarm stop relative speed difference). The present embodiment is characterized in that the alarm is restarted unless the relative speed difference is decelerated to 1 km / h or less in 4.3 seconds. In step S31, it is determined whether or not the current approaching relative speed difference exceeds 1 km / h. If it is 1 Km / h or less, the alarm is not restarted and the process returns to step S3. 1K
If it exceeds m / h, the process proceeds to step S18, the alarm flag is set to 1, the alarm is generated again (S19), and the process returns to step S3. After the warning is issued again, the warning is continued until the approaching relative speed difference becomes 1 km / h or less (determined in step S6). When the approaching relative speed difference becomes 1 km / h or less, steps S6 to S6 are performed.
7, the alarm is stopped and the process returns to step S1.

When the accelerator pedal is returned and the idle switch is on, the alarm prohibition flag is 1, but if the driver depresses the accelerator pedal again in this state, step S11 To S1
2, the alarm prohibition flag is reset to 0, and then the normal flow when the idle switch is turned off (S13 → S14) is performed, and the same operation as described above is performed.

With this, it is possible to timely issue an alarm indicating that the inter-vehicle distance is inadequate without giving the driver annoyance due to an excessive number of alarms, and even when the accelerator is off after the alarm has been stopped. When the vehicle approaches the vehicle, the alarm can be restarted.

[0045]

As described above, according to the first aspect of the present invention, after the generation of the alarm is stopped, when the own vehicle and the preceding vehicle are in a predetermined situation, the alarm control means issues the alarm again from the alarm means. As a result, the driver's comfort is improved by avoiding excessive warning to the driver, and the distance from the vehicle to the front target is shorter than the predetermined distance determined according to the vehicle speed of the vehicle after the warning is stopped. In this case, it is possible to improve driving comfort and driving safety by re-issuing the alarm.

A second aspect of the invention is provided with a relative speed calculating means for calculating a relative speed difference between the own vehicle and the front target from the amount of change in the detected distance within a unit time, and the relative speed calculation means is provided between the own vehicle and the front target. When the relative speed difference is greater than a predetermined value, an alarm is issued by the alarm means, so the relative speed difference confirms the proximity of the host vehicle and the target in front, and the alarm is re-issued appropriately to ensure comfortable driving. And driving safety can be improved.

A third aspect of the invention is provided with a relative speed calculating means for calculating a relative speed difference between the own vehicle and the front target from the amount of change in the detected distance per unit time, If the relative acceleration of the vehicle is equal to or greater than a predetermined value and the inter-vehicle distance is equal to or greater than the inter-vehicle distance for which an alarm is issued, an alarm is issued by the alarm means, so that the proximity state of the host vehicle and the front target can be accurately grasped. Thus, it is possible to improve the comfort of driving and the safety of driving by appropriately issuing the alarm again.

A fourth invention is provided with a relative speed calculating means for calculating a relative speed difference between the own vehicle and the front target from the amount of change in the detected distance per unit time, and after the alarm is stopped, the relative speed is calculated. When the time from the detection of the deceleration operation detection means is a predetermined time or more and the relative speed difference is a predetermined value or more, the warning means issues an alarm, so the proximity state of the host vehicle and the target in front Can be more accurately grasped, the alarm can be properly regenerated, and driving comfort and driving safety can be improved.

[Brief description of drawings]

FIG. 1 is a diagram corresponding to a claim of the present invention.

FIG. 2 is a block diagram showing an embodiment of an inter-vehicle distance warning device according to the present invention.

FIG. 3 is a flowchart showing the operation of the present invention.

FIG. 4 is a flowchart showing the operation of the present invention.

FIG. 5 is a diagram showing the relationship between the warning inter-vehicle distance and the speed of the own vehicle in the relative speed difference.

FIG. 6 is a diagram showing a relationship between a relative speed difference and an alarm condition.

FIG. 7 is a diagram showing a relationship between a relative speed difference and an alarm condition.

FIG. 8 is a flowchart showing the operation of the present invention.

FIG. 9 is a flowchart showing the operation of the present invention.

FIG. 10 is a flowchart showing the operation of the present invention.

FIG. 11 is a flowchart showing the operation of the present invention.

[Explanation of symbols]

 1 inter-vehicle distance sensor 3 vehicle speed sensor 5 engine idle determination switch 7 CPU 11 alarm buzzer 13 inter-vehicle distance calculation unit 15 relative speed difference calculation unit 17 relative acceleration calculation unit 19 danger determination unit 23 timer 101 vehicle speed detection unit 103 distance detection unit 105 comparison unit 107 Warning Means 109 Deceleration Operation Detecting Means 111 Alarm Stopping Means 113 Alarm Control Means 115 Relative Speed Difference Calculating Means 117 Time Measuring Means

Claims (4)

[Claims] 1. A vehicle speed detecting means for detecting a vehicle speed of the own vehicle, a distance detecting means for detecting a distance from the own vehicle to a front target, and a distance from the own vehicle to the front target detected by the distance detecting means. Comparing means for comparing the distance and a predetermined distance determined according to the vehicle speed of the own vehicle detected by the vehicle speed detecting means, and the distance from the own vehicle to the front target object by the comparing means by the vehicle speed detecting means. Warning means for giving an alarm when the distance is shorter than a predetermined distance determined according to the detected vehicle speed of the vehicle; and the distance from the vehicle to the front target detected by the comparison means by the vehicle speed detection means. Deceleration operation detection means for detecting whether or not an operation for decelerating the own vehicle is performed when the distance is shorter than a predetermined distance determined according to the vehicle speed of the vehicle; An inter-vehicle distance warning device comprising: an alarm stop means for stopping an alarm by the alarm means when a speeding operation is detected; and, after the alarm is stopped by the alarm stop means, the front target and the own vehicle. And a warning control means for giving a warning by the warning means in a predetermined situation. 2. A relative speed difference calculating means for calculating a relative speed difference between the own vehicle and a front target from the amount of change in the distance detected by the distance detecting means in a unit time,
The inter-vehicle distance according to claim 1, wherein the relative speed difference calculated by the relative speed difference calculating means is a predetermined value or more when the front target and the own vehicle in the alarm control means are in a predetermined situation. Distance alarm device. 3. A relative speed difference calculating means for calculating a relative speed difference between the own vehicle and a front target from the amount of change in the distance detected by the distance detecting means in a unit time,
When the target object in front of the alarm control means and the host vehicle are in a predetermined situation, the difference between the host vehicle and the target object in front of the relative speed difference calculated by the relative speed difference calculating means in the unit time is calculated. The relative acceleration is calculated, and when the relative acceleration is equal to or greater than a predetermined value, and the distance detected by the distance detection means is equal to or greater than the distance at which the alarm means issues an alarm. Inter-vehicle distance warning device. 4. A relative speed difference calculating means for calculating a relative speed difference between the own vehicle and a front target from the amount of change in the distance detected by the distance detecting means in a unit time,
When the target in front of the alarm control means and the own vehicle are in a predetermined situation, after the alarm is stopped by the alarm stop means, a time measuring means for measuring the time from the time of detecting deceleration by the deceleration operation detecting means. 2. The inter-vehicle distance warning device according to claim 1, wherein the time measured by the above is a predetermined time or more, and the relative speed difference calculated by the relative speed difference calculating means is a predetermined value or more.