JP2545868Y2 - Rear-end collision prevention device - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rear-end collision prevention device which measures the distance and speed between a preceding vehicle and a host vehicle and issues an alarm when there is a risk of rear-end collision.

[0002]

2. Description of the Related Art FIG. 3 is a block diagram showing a configuration example of a conventional rear-end collision prevention device. In the figure, 1 is an inter-vehicle distance measuring unit, 2
Denotes a vehicle speed measuring unit, 3 denotes a safe inter-vehicle distance calculating unit, 4 denotes a danger determining unit, and 5 denotes an alarm generating unit.

The inter-vehicle distance measuring unit 1 is constituted by, for example, a pulse laser radar device, measures the inter-vehicle distance between the preceding vehicle and the own vehicle, and outputs the signal to the safe inter-vehicle distance calculating unit 3 as a signal S1. FIG. 4 is a diagram for explaining the principle of measuring the distance between vehicles when a pulse laser radar device is used. In this case, the pulse laser radar device PRL mounted in front of the own vehicle C1 emits a pulse laser beam as indicated by OPL in FIG. 4B toward the preceding vehicle C2, and this emitted laser beam OPL The light OPR reflected by a reflector (reflex reflector) RFL attached to the rear of the car C2 is detected by a photodetector provided in the pulse laser radar device PRL, and the time Δ from the emission of laser light to the detection of reflected light is detected.
The distance is measured by measuring t and calculating the distance based on the following equation. R = (C · Δt) / 2 (1) where R indicates the distance between vehicles and C indicates the speed of light.

The host vehicle speed measuring unit 2 is constituted by a speedometer, measures the rotational speed of the wheels of the host vehicle, and outputs an electric signal S2 indicating the host vehicle speed V1 to the safe inter-vehicle distance calculating unit 3.

[0005] The safe inter-vehicle distance calculating section 3 is constituted by, for example, a microcomputer or the like.
From the own vehicle C1 and the preceding vehicle C2 from the vehicle, calculate the rate of change of the inter-vehicle distance based on the time-series inter-vehicle distance data, calculate the relative speed, and obtain the obtained relative speed and the relative speed from the own vehicle speed measurement unit 2. The speed V2 of the preceding vehicle C2 is calculated based on the traveling speed data V1 of the own vehicle C1, and the own vehicle speed V1 and the preceding vehicle speed V2,
In addition, the safe inter-vehicle distance S from the pre-set idle time
R is calculated and output to the danger determining unit 4 as a signal S3.

FIG. 5 is a diagram for explaining the concept of the safe inter-vehicle distance. FIG. 5A shows a state in which the own vehicle C1 is traveling at a speed V1 and the preceding vehicle C2 is traveling at a speed V2. FIG.
The state where the driver notices danger from the state of (a) and applies the brake to stop the own vehicle C1 is shown. The distance D traveled by the vehicle C1 from when the driver notices the danger to when the driver stops applying the brake is calculated as the following formula (2). It can be expressed as the sum of P and the distance Q traveled from when the brake is applied to when the vehicle C1 stops. D = P + Q (2)

If the distance from the preceding vehicle C2 is maintained at zero or more in the section D, collision between the own vehicle C1 and the preceding vehicle C2 can be avoided. In detecting danger from the inter-vehicle distance R between the own vehicle C1 and the preceding vehicle C2, if the collision of the preceding vehicle C2 is most likely to occur, the own vehicle C1 is used.
This is when the driver of the preceding vehicle C2 applies a brake and the preceding vehicle C2 decelerates at the same time when the driver senses danger. Under this condition, the deceleration of the own vehicle C1 and the preceding vehicle C2
By setting the deceleration of the vehicle and the idling time, the safe inter-vehicle distance can be calculated from the own vehicle speed V1 and the preceding vehicle speed V2.

The danger determining unit 4 is composed of, for example, a microcomputer, and compares the safe inter-vehicle distance SR obtained by the safe inter-vehicle distance calculation unit 3 with the measured inter-vehicle distance R. If the distance is equal to or less than the inter-vehicle distance SR, the determination signal S4 is output to the alarm generator 5, and the alarm generator 5 is operated.

The alarm generator 5 is composed of, for example, a buzzer, a chime, a lamp, etc.
It is notified that the inter-vehicle distance R between the vehicle and the preceding vehicle C2 is less than or equal to the safe inter-vehicle distance SR with respect to the traveling speed, and there is a danger of a rear-end collision.

The operation of the above configuration will be described with reference to the flowchart of FIG. First, the own vehicle speed V1 is measured by the own vehicle speed measuring unit 2 of the own vehicle C1 (S1),
The measured own vehicle speed V1 is input to the safe inter-vehicle distance calculation unit 3. Further, a laser pulse light is emitted from the pulse laser radar device as the inter-vehicle distance measuring unit 1 mounted on the own vehicle C1 toward the preceding vehicle C2, and the light reflected by the reflector attached to the preceding vehicle C2 is emitted. The inter-vehicle distance R between the own vehicle C1 and the preceding vehicle C2 is detected by the pulse laser radar device (S2), and is input to the safe inter-vehicle distance calculation unit 3 as the measured inter-vehicle distance.

The safety inter-vehicle distance calculation unit 3 first calculates the conversion rate of the inter-vehicle distance based on the time-series inter-vehicle distance data between the own vehicle C1 and the preceding vehicle C2 from the inter-vehicle distance measurement unit 1, and calculates the relative speed. Is required (S3). Next, the speed V2 of the preceding vehicle is determined based on the obtained relative speed and the traveling speed data V1 of the own vehicle C1 from the own vehicle speed measuring unit 2 (S
4). Then, the obtained own vehicle speed V1 and the preceding vehicle speed V2 are obtained.
The safe inter-vehicle distance SR is calculated from the pre-set idle running time (S5) and output to the danger determination unit 4.

The danger determining unit 4 includes a safe inter-vehicle distance calculating unit 3
Is compared with the measured inter-vehicle distance R to determine whether or not the current inter-vehicle distance is dangerous (S6). If the measured inter-vehicle distance R is larger than the safe inter-vehicle distance SR, it is determined that the vehicle is safe and the process returns to step S1.

On the other hand, if the measured following distance R is equal to or less than the safe following distance SR, it is determined to be dangerous, and a signal S4 is output to the alarm generator 5 to issue an alarm.
As a result, the alarm generation unit 5 informs the driver of the vehicle C1.
The inter-vehicle distance R between the vehicle and the preceding vehicle C2 is less than or equal to the safe inter-vehicle distance SR with respect to the traveling speed, and it is notified that there is a danger of rear-end collision (S7). After that, the driver who receives the warning releases the accelerator, applies the brake again, decelerates, and proceeds to step S
An alarm is issued until it is determined to be safe at 6.

[0014]

In the rear-end collision prevention device, as can be seen from the above equation (2), the idle distance P, that is, the idle time TP has a great influence on the safe inter-vehicle distance. The idle running time Tp is, for example, the time when the driver recognizes the warning when the alarm is issued, determines that it is dangerous, and applies the brakes until the brakes come into effect. It greatly depends on the braking reaction time. The braking reaction time varies greatly depending on individual differences such as the driver's age and experience.

In the above-described conventional collision prevention apparatus, the safe inter-vehicle distance is calculated with the free running time as a fixed value. Therefore, in order to ensure safety, the free running time must be set according to the driver who has a slow response. However, it is not an appropriate value for a fast-responding driver, and an excessive warning is issued for a fast-responding driver, which has disadvantages such as discomfort and discomfort.

The present invention has been made in view of the above circumstances, and a purpose thereof is to provide a rear-end collision prevention device which can issue an alarm according to a driver's individual difference and does not give the driver any discomfort or discomfort. Is to provide.

[0017]

In order to achieve the above object, according to the present invention, an inter-vehicle distance measuring unit for measuring an inter-vehicle distance between the own vehicle and a preceding vehicle, and an own vehicle speed measuring unit for measuring a speed of the own vehicle. And a measurement result of the inter-vehicle distance measuring unit and the own vehicle speed measuring unit, and a safe inter-vehicle distance calculating unit that calculates a safe inter-vehicle distance based on the idle time, and the calculated safe inter-vehicle distance and the measured inter-vehicle distance. A danger determining unit that determines that there is danger when the measured inter-vehicle distance is equal to or less than the safe inter-vehicle distance and outputs a determination signal, an alarm generation unit that receives the determination signal and issues an alarm, and a speed braking unit of the own vehicle. A detection unit that detects that the operation has been performed; an idle running time measurement unit that measures the time from when an alarm is issued in response to the determination signal and the detection signal of the detection unit to when a braking operation is started; Time data obtained from the travel time measurement unit Reset the empty run time Zui, and a sky run time setting unit updates the empty run time for calculating the safe inter-vehicle distance calculating section by the set value.

[0018]

According to the present invention, the own vehicle speed is measured by the own vehicle speed measuring unit, and the measured own vehicle speed is inputted to the safe inter-vehicle distance calculating unit. The inter-vehicle distance between the host vehicle and the preceding vehicle is calculated by the inter-vehicle distance measurement unit mounted on the own vehicle, and is input to the safe inter-vehicle distance calculation unit as the measured inter-vehicle distance. In the safety inter-vehicle distance calculation unit, the safety inter-vehicle distance is calculated from the input measured inter-vehicle distance and the own vehicle speed, and the idle running time,
Output to the danger determination unit. The danger determination unit compares the safe inter-vehicle distance obtained by the safe inter-vehicle distance calculation unit with the measured inter-vehicle distance, and when the measured inter-vehicle distance is equal to or less than the safe inter-vehicle distance, it is determined to be dangerous and a determination signal is issued. It is output to the generation unit and the idle running time measurement unit. Thus, the warning generation unit informs the driver that there is a risk of a rear-end collision when the inter-vehicle distance between the host vehicle and the preceding vehicle is equal to or less than the safe inter-vehicle distance with respect to the traveling speed. Further, the idle running time measuring unit recognizes that an alarm has been issued by the input of the determination signal. At this time, the detection unit determines whether or not the driver who has received the warning has actuated the speed braking unit in consideration of danger, and if it is determined that the driver has been activated, the detection unit notifies the idle running time measurement unit. Output a detection signal.

The idle running time measuring unit measures the time from when an alarm is issued from the alarm generating unit to when the driver operates the speed braking means in response to the input judgment signal and detection signal. The result is output to the idle running time setting section. In the idle running time setting unit, the optimal idle running time is reset from a plurality of idle running time data obtained in the past by the idle running time measuring unit, and is output to the safe inter-vehicle distance calculating unit. Thereby, the idle time data for calculation of the safe inter-vehicle distance calculation unit is updated with the reset optimal idle time data. The next safe inter-vehicle distance calculation in the safe inter-vehicle distance calculation unit is performed based on the optimum idle running time provided by the idle running time setting unit and according to the physical condition of the driver and the response speed to the warning.

[0020]

FIG. 1 is a block diagram showing an embodiment of a rear-end collision prevention device according to the present invention. The same components as those in FIG. 3 showing a conventional example are denoted by the same reference numerals. That is, 1 is an inter-vehicle distance measurement unit, 2 is a vehicle speed measurement unit, 3a is a safe inter-vehicle distance calculation unit, 4 is a danger determination unit, 5 is an alarm generation unit, 6 is a brake detection unit, and 7 is an idle running time measurement unit. , 8 indicate idle running time setting units.

The safe inter-vehicle distance calculating section 3a is constituted by, for example, a microcomputer or the like, and converts the inter-vehicle distance conversion rate based on the time-series inter-vehicle distance data between the own vehicle C1 and the preceding vehicle C2 from the inter-vehicle distance measuring section 1. Is calculated to calculate the relative speed, and based on the obtained relative speed and the running speed data V1 of the own vehicle from the own vehicle speed measuring unit 2, the speed V2 of the preceding vehicle is calculated.
Is calculated based on the own vehicle speed V1, the preceding vehicle speed V2, and the optimum idle running time PT updated as needed by the idle running time setting unit 8, and the danger determining unit 4 is used as the signal S3a. Output to

The brake detecting section 6 detects that the brake is applied, and notifies the idle running time measuring section 7. Specifically, for example, when the brake is a pedal type, when the brake pedal is depressed, a detection signal S6 is generated and output to the idle running time measuring unit 7.

The idle running time measuring unit 7 is included in, for example, a signal processing device including a microcomputer as in the safe inter-vehicle distance calculating unit 3a and the danger determining unit 4, and the like.
In response to the output judgment signal S4 of the danger judgment unit 4 and the output detection signal S6 of the brake detection unit 6, the idle running time from when the alarm is issued from the alarm generation unit 5 to when the driver applies the brake is measured. To the idle running time setting unit 8.

The idle running time setting unit 8 resets the optimum idle running time PT from one or a plurality of idle running time data obtained in the past by the idle running time measuring unit 7 and outputs a safe inter-vehicle distance calculating unit as a signal S8. 3a, and updates the calculation idle running time with the reset value. As a method of setting the free running time PT, for example, a method of taking an average value of the free running time data and setting it as a set value, a method of obtaining a regression coefficient of the free running time data, and performing prediction are adopted.

Next, the operation of the above configuration will be described with reference to the flowchart of FIG. First, the own vehicle speed V1 is measured by the own vehicle speed measuring unit 2 of the own vehicle C1 (ST1),
The measured own vehicle speed V1 is input to the safe inter-vehicle distance calculation unit 3a. Further, a laser pulse light is emitted from the pulse laser radar device as the inter-vehicle distance measuring unit 1 mounted on the own vehicle C1 toward the preceding vehicle C2, and the light reflected by the reflector attached to the preceding vehicle C2 is emitted. The inter-vehicle distance R between the own vehicle C1 and the preceding vehicle C2 is detected by the laser radar device (ST2), and is input to the safe inter-vehicle distance calculation unit 3a as measured inter-vehicle distance data.

The safety inter-vehicle distance calculation unit 3a first calculates the conversion rate of the inter-vehicle distance based on the time-series inter-vehicle distance data between the own vehicle C1 and the preceding vehicle C2 from the inter-vehicle distance measurement unit 1, and calculates the relative speed. Is required (ST3). Next, the speed V2 of the preceding vehicle C2 is obtained based on the obtained relative speed and the traveling speed data V1 of the own vehicle C1 from the own vehicle speed measuring unit 2 (ST4). Then, the safe inter-vehicle distance SR is calculated from the obtained own vehicle speed V1, the preceding vehicle speed V2, and the idling time data (ST5), and is output to the danger determining unit 4 as a signal S3a.

The danger determination unit 4 includes a safe inter-vehicle distance calculation unit 3
The safety inter-vehicle distance SR obtained in step a is compared with the measured inter-vehicle distance R, and it is determined whether or not the current inter-vehicle distance is dangerous (ST6). If the measured inter-vehicle distance R is larger than the safe inter-vehicle distance SR, it is determined that the vehicle is safe and the process returns to step S1.

On the other hand, when the measured following distance R is equal to or less than the safe following distance SR, it is determined to be dangerous, and a signal S4 is output to the alarm generator 5 to issue an alarm.
As a result, the alarm generation unit 5 informs the driver of the vehicle C1.
It is informed that the inter-vehicle distance R between the vehicle and the preceding vehicle C2 is less than or equal to the safe inter-vehicle distance SR with respect to the traveling speed and there is a danger of a rear-end collision (ST7).

The output determination signal S4 of the danger determination unit 4 is also input to the idle running time measurement unit 7. As a result, the idle running time measuring section 7 recognizes that an alarm has been issued. At this time, the brake detection unit 6 determines whether the driver who has received the warning senses danger, releases the accelerator, and applies the brake (ST8). In step ST8,
When it is determined that the brake is applied, a detection signal S6 is output from the brake detection unit 6 to the idle running time measurement unit 7.

The idle running time measuring unit 7 receives the output judgment signal S4 of the danger judging unit 4 and the output detection signal S6 of the brake detecting unit 6, and after the alarm is issued from the alarm generating unit 5, the driver applies the brake. Is measured (ST9), and the result is output to the idle running time setting section 8 as a signal S7.

The idle running time setting section 8 includes an idle running time measuring section 7
The optimum idle running time PT is reset from a plurality of idle running time data obtained in the past (ST10), and is output as a signal S8 to the safe inter-vehicle distance calculating section 3a to output the free running time data of the safe inter-vehicle distance calculating section 3a. Is updated with the input idle running time data, and the operation returns to the operation of step ST1. And
The next calculation of the safe inter-vehicle distance by the safe inter-vehicle distance calculation unit 3a is performed based on the free running time PT given by the free running time setting unit 8 according to the physical condition of the driver and the response speed to the warning.

As described above, according to this embodiment,
The time from when the warning is issued in the idle running time measuring section 7 to when the driver applies the brake is obtained, and based on the time data, the idle running time setting section 8 sets and updates the optimal idle running time, and sets the optimal running time. Since the safe inter-vehicle distance is calculated using the idle running time, a safe inter-vehicle distance according to the driver can be obtained. Therefore, an alarm can be issued according to the individual difference of the driver, and the driver does not feel uncomfortable or uncomfortable.

[0033]

[Effects of the Invention] As described above, according to the present invention,
An alarm can be issued according to the individual differences of the drivers,
A rear-end collision prevention device that does not cause discomfort or discomfort to the driver can be realized.

[Brief description of the drawings]

FIG. 1 is a block diagram showing one embodiment of a rear-end collision prevention device according to the present invention.

FIG. 2 is a flowchart illustrating an operation according to the present invention.

FIG. 3 is a block diagram of a conventional rear-end collision prevention device.

FIG. 4 is a diagram for explaining the principle of measuring the distance between vehicles.

FIG. 5 is a diagram for explaining the concept of a safe inter-vehicle distance.

FIG. 6 is a flowchart for explaining the operation of the apparatus in FIG. 3;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Inter-vehicle distance measuring unit 2 ... Own vehicle speed measuring unit 3a ... Safe inter-vehicle distance calculating unit 4 ... Danger determining unit 5 ... Warning generating unit 6 ... Brake detecting unit 7 ... Free running time measuring unit 8 ... Free running time setting unit

Claims (1)

(57) [Scope of request for utility model registration] An inter-vehicle distance measuring unit for measuring an inter-vehicle distance between the own vehicle and a preceding vehicle; an own vehicle speed measuring unit for measuring a speed of the own vehicle; and a measurement of the inter-vehicle distance measuring unit and the own vehicle speed measuring unit. result,
And a safe inter-vehicle distance calculation unit that calculates the safe inter-vehicle distance based on the idle running time, and compares the calculated safe inter-vehicle distance with the measured inter-vehicle distance. A danger determination unit that determines and outputs a determination signal; an alarm generation unit that receives the determination signal and issues an alarm; a detection unit that detects that a speed braking unit of the own vehicle is activated; and the determination signal and the detection unit An idle running time measuring unit that measures the time from when an alarm is issued in response to the detection signal to when the braking operation is started, and an idle running time based on the time data obtained from the idle running time measuring unit. An idle running time setting unit that resets and updates the idle running time for calculation of the safe inter-vehicle distance calculating unit based on the set value.