JPH06201830A - Device for controlling alarm on vihicular distance - Google Patents

Abstract

PURPOSE:To generate an alarm rapidly and to prevent collision to a forward vehicle in a dangerous situation when another vehicle interrupts and the vehicle distance changes abruptly. CONSTITUTION:An ECU 1 detects the driving speed of its own vehicle and detects the distance between a forward vehicle and its own vehicle at each certain timing by the use of a vehicle distance detector 5. When the difference between the last vehicle distance and the current vehicle distance exceeds a certain distance and the vehicle distance is shorter than the interrupt alarm distance which is obtaned previously for the driving vehicle speed according to the detection results, an alarm is generated by a buzzer 6 to inform of danger.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an inter-vehicle distance alarm control device for issuing an alarm when the inter-vehicle distance from a front vehicle is equal to or shorter than a predetermined alarm distance.

[0002]

2. Description of the Related Art An inter-vehicle distance alarm control device is a device which issues an alarm when the inter-vehicle distance from a preceding vehicle is equal to or less than a predetermined warning distance corresponding to a traveling vehicle speed. In order to measure the inter-vehicle distance, for example, a so-called laser radar is used which measures the inter-vehicle distance by irradiating the front with a laser beam or the like and measuring the arrival time of the reflected light from the preceding vehicle. The warning distance is predetermined according to the relative speed between the own vehicle and the preceding vehicle and the traveling vehicle speed of the own vehicle. The alarm is also configured to stop when the driver steps on the brake pedal. As an invention disclosing such a prior art, Japanese Patent Laid-Open No. 57-19685 is cited.

[0003]

In the prior art as described above, in order to determine whether the inter-vehicle distance is equal to or shorter than the warning distance,
In addition to the traveling speed of the host vehicle, the relative speed between the host vehicle and the preceding vehicle must be calculated. Generally, a certain required time is required to calculate the relative speed. Therefore, in a dangerous situation where another vehicle interrupts between the host vehicle and the preceding vehicle, causing a rapid change in the inter-vehicle distance, it is necessary to quickly issue an alarm, but the relative speed is calculated. It takes time to delay the alarm. In particular, in such an interrupt state, the value of the relative speed is not stable, so that the calculation of the relative speed is often delayed. As a result, the risk of a rear-end collision with the vehicle in front also increases. A prior art of an alarm device for notifying that the inter-vehicle distance becomes equal to or less than the alarm distance due to interruption of another vehicle without calculating the relative speed is disclosed in Japanese Patent Laid-Open No. 61-246688. In this prior art, it is unclear how to judge interruption of another vehicle.

An object of the present invention is to promptly generate an alarm even in a dangerous state where the calculation of the relative speed is delayed such that another vehicle interrupts between the own vehicle and the preceding vehicle and the inter-vehicle distance changes rapidly. An object of the present invention is to provide an inter-vehicle distance warning control device capable of preventing a rear-end collision with a vehicle in front.

[0005]

SUMMARY OF THE INVENTION According to the present invention, an inter-vehicle distance is alarmed by comparing the inter-vehicle distance with a front vehicle with an alarm distance determined based on the relative speed between the own vehicle and the front vehicle and the traveling speed of the own vehicle. In the inter-vehicle distance warning control device that controls to generate an alarm when the distance is less than or equal to a distance, a detecting unit that detects a sudden change state in which a change in inter-vehicle distance becomes a predetermined value or more within a predetermined time,
In response to the output from the detection means, when the inter-vehicle distance suddenly changes, the inter-vehicle distance warning control device including a control means for controlling to issue an alarm if the inter-vehicle distance is a predetermined value or less. is there.

[0006]

According to the present invention, the inter-vehicle distance warning control device includes:
Detecting means and control means are included. The detection means detects a sudden change state in which a change in the inter-vehicle distance from the preceding vehicle becomes a predetermined value or more within a predetermined time, such as when an interruption occurs in another vehicle. The control means responds to the output from the detection means, and when the inter-vehicle distance with the preceding vehicle suddenly changes due to an interruption of another vehicle, controls so as to issue an alarm if the inter-vehicle distance is equal to or less than a predetermined value. In response to a dangerous situation in which another vehicle interrupts between the host vehicle and the preceding vehicle and the distance between the vehicles changes rapidly, the distance between the host vehicle and the preceding vehicle is calculated without calculating the relative speed between the host vehicle and the preceding vehicle. Since the detection and control are performed based only on the distance, it is possible to quickly issue an alarm and notify the danger without delay.

[0007]

1 is a block diagram showing the electrical construction of an embodiment of the present invention. Inter-vehicle distance warning control device (EC
A vehicle speed detector 2 detects the traveling speed of the host vehicle. The inter-vehicle distance detector 5 detects the inter-vehicle distance from the preceding vehicle based on the distance signal 4 transmitted from the distance sensor 3 attached to the vehicle to measure the inter-vehicle distance.
Based on these detection results, when it is determined that the actual inter-vehicle distance becomes shorter than the warning distance previously obtained corresponding to the traveling vehicle speed and it is dangerous, the buzzer 6 issues a warning to notify the danger. The vehicle speed detector 2 is provided with, for example, a magnet piece that rotates in association with the rotation of a propeller shaft or a speedometer cable, and changes in the magnetic field due to the rotation of the magnet piece are provided at a fixed position such as a reed switch or a magnetic resistance element. It is realized by detecting with. Also,
The inter-vehicle distance detector 5 is realized by, for example, a so-called laser radar that irradiates a laser beam forward and obtains the distance based on the arrival time of the light reflected by the preceding vehicle.
Further, the relative speed is obtained from the change rate of the inter-vehicle distance. The value of the relative speed when the vehicle approaches the front vehicle is positive, and the value when the vehicle is separated from the front vehicle is negative. The alarm distance AR is obtained in advance as shown in FIG. 2 based on the traveling vehicle speed and the relative speed, and the graph shown in FIG. 2 is stored in the memory 7 in the ECU 1 as a map.

In normal control, the results detected by the vehicle speed detector 2 and the inter-vehicle distance detector 5 are input to the processing circuit 9 realized by a microcomputer or the like via the input interface 8. The processing circuit 9 calculates the relative speed from the change rate of the inter-vehicle distance detected by the inter-vehicle distance detector 5. From the calculated relative speed and the traveling vehicle speed of the host vehicle, the alarm distance AR is calculated using the map of FIG. 2 stored in the memory 7. The warning distance AR is compared with the inter-vehicle distance, and when the inter-vehicle distance is less than or equal to the warning distance AR, a warning signal is output through the output interface 10 and the buzzer 6 issues a warning. The alarm is stopped when the driver can step on the brake pedal to maintain a safe inter-vehicle distance. The braking operation is realized by turning on the brake switch 11 when the driver steps on the brake pedal. It should be noted that when another vehicle interrupts and the following conditions are met, it is possible to determine whether the inter-vehicle distance is less than or equal to the warning distance and issue a warning, without calculating the relative speed. is there. With the inter-vehicle distance detector 5, for example, 50
The inter-vehicle distance is detected every msec. The first condition is the last time,
That is, the change in the inter-vehicle distance before 50 msec and the current inter-vehicle distance is a constant distance, for example, 5 m or more.
The second condition is that the inter-vehicle distance is equal to or shorter than the interrupt warning distance ARV when the first condition is satisfied. Here, the interruption warning distance ARV is an advance warning for the traveling vehicle speed of the own vehicle with the inter-vehicle distance that determines whether or not an alarm is issued when another vehicle interrupts and the inter-vehicle distance changes suddenly. It is something to set. Interruption alarm distance A
The RV is calculated based on the traveling vehicle speed of the own vehicle from the map shown in FIG. This map is stored in the memory 7 in the ECU 1.

FIG. 4 is a flow chart for explaining the alarm control operation of the embodiment of the present invention. This flowchart shows the control operation every 50 msec. Step n
When 1 is the initialization process, the alarm time counter CA at interrupt
The RV count number is set to the maximum value. The interrupt time alarm time counter CARV is used to count the unit of time and count the time when the alarm is issued when the interrupt condition is satisfied. In step n2,
The inter-vehicle distance detector 5 detects the inter-vehicle distance from the preceding vehicle. In step n3, the vehicle speed detector 2 calculates the traveling vehicle speed VS. In step n4, the count number of the interruption warning time counter CARV, which is timed for each unit time, is incremented, that is, increased. Immediately after the initialization process, the count number of the alarm time counter CARV during interruption is set to the maximum value, and therefore the process directly proceeds to step n5. In step n5, it is determined whether or not the time corresponding to the count number of the alarm time counter at interrupt CARV is within 1 second.
When it is determined that the time is one second or longer, the process proceeds to step n6, and the inter-vehicle distance L _{i-1 at the} previous time, that is, 50 msec before is reached.
It is determined whether or not the difference L _i−1 −L _i between the current vehicle-to-vehicle distance L _i and the current vehicle-to-vehicle distance L _i is a fixed distance, for example, 5 m or more. If it is determined that the distance is 5 m or more, it is considered that the inter-vehicle distance has changed abruptly due to an interruption of another vehicle, so the process proceeds to step n7, and the traveling vehicle speed of the own vehicle is calculated from the map shown in FIG. Check the interrupt warning distance ARV. In step n8,
It is determined whether or not the inter-vehicle distance L _i this time is less than or equal to the interrupt warning distance ARV. If it is determined that the distance is equal to or shorter than the interruption warning distance ARV, it is considered that another vehicle is interrupted and it is in a dangerous state. Therefore, in step n9, the count number of the interruption warning time counter CARV is set to 0, and then the step An alarm is generated by the buzzer 6 at n10. When it is determined in step n6 that the difference L _i-1 −L _i between the previous vehicle _-to- vehicle distance L _i-1 and the current vehicle _-to- vehicle distance L _i is less than 5 m, or in step n8, the current vehicle-to-vehicle distance L _{If i} is determined to be longer than the interrupt warning distance ARV, the routine proceeds to step n11 to calculate the relative speed in accordance with normal control. In step n12, the warning distance AR is operated from the map shown in FIG. 2 based on the obtained relative speed and the traveling vehicle speed of the own vehicle. In step n13, it is determined whether or not the inter-vehicle distance L _i this time is less than or equal to the warning distance AR. When it is determined that the distance is equal to or shorter than the warning distance AR, the inter-vehicle distance is short and it is in a dangerous state.
Then, the alarm is generated by the buzzer 6. Inter-vehicle distance L _i
Is determined to be longer than the warning distance AR, the inter-vehicle distance is appropriate, and the warning is stopped in step n14.
When the above control operation is completed, the operation is returned to step n2 and the same operation is repeated. When it is determined in step n5 that the time corresponding to the count number of the alarm time counter during interrupt CARV is within 1 second,
The process proceeds to step n10 and the alarm generation is continued. Thus, in this embodiment, when the interrupt condition is satisfied, the alarm is generated for at least 1 second. Therefore, in response to a dangerous situation in which the inter-vehicle distance is interrupted and the inter-vehicle distance suddenly changes, an operation different from the normal control operation is performed, and the alarm can be promptly issued without calculating the relative speed. it can.

[0010]

As described above, according to the present invention, in a dangerous state in which another vehicle interrupts between the own vehicle and the preceding vehicle and the inter-vehicle distance changes rapidly, the relative distance between the own vehicle and the preceding vehicle is large. Since the judgment is based only on the distance to the preceding vehicle without calculating the speed, it is possible to quickly issue an alarm even if the calculation of the relative speed is delayed, and to notify the driver of the danger without delay. .

[Brief description of drawings]

FIG. 1 is a block diagram showing an electrical configuration of an embodiment of the present invention.

FIG. 2 is a graph showing a relationship between a traveling vehicle speed VS and a relative speed and an alarm distance AR according to an embodiment of the present invention.

FIG. 3 is a graph showing a relationship between a traveling vehicle speed VS and an interruption warning distance ARV according to an embodiment of the present invention.

FIG. 4 is a flowchart illustrating an alarm control operation according to an embodiment of the present invention.

[Explanation of symbols]

 1 ECU 2 Vehicle speed detector 3 Distance sensor 4 Distance signal 5 Distance detector 6 Buzzer 7 Memory 8 Input interface 9 Processing circuit 10 Output interface 11 Brake switch

Claims (1)

[Claims] 1. An inter-vehicle distance with a preceding vehicle is compared with an alarm distance determined based on a relative speed between the own vehicle and the preceding vehicle and a traveling speed of the own vehicle, and an alarm is issued when the inter-vehicle distance is less than or equal to the alarm distance. In the inter-vehicle distance warning control device that controls as described above, when the inter-vehicle distance changes suddenly in response to the output from the detection means and the detection means that detects a sudden change state in which the change in inter-vehicle distance exceeds a certain value within a predetermined time An inter-vehicle distance warning control device, comprising: a control unit that controls to issue an alarm if the inter-vehicle distance is equal to or less than a predetermined value.