JPH03176800A - Alarming device for short distance between vehicles - Google Patents

Abstract

PURPOSE:To prevent the generation of misalarm due to noise waves from vehicles other than the forward traveling vehicle and to maintain safety driving by automaticaly or manually switching the level of an inter-vehicle distance limit threshold in accordance with the traveling speeds of vehicles. CONSTITUTION:A radio wave received by a radar antenna 2 is received by a receiving circuit 41 in a radar equipment 4, and when the value of a threshold circuit 42 is less than a previously determined threshold, the receiving signal is invalidated. When the value is more than the threshold, the receiving signal is sent to a program control circuit 7 through an input interface 6. A traveling speed is always outputted from a speed detecting circuit 9 to a threshold switching means 43, which receives the output and automatically sets up the threshold to 2' when the vehicle is traveling at a comparatively low speed like the traveling on a general road. At the time of traveling at a comparatively high speed like the traveling on an express-highway, the threshold level is switched to the level shown by 1'. Thus, the generation of misalarm due to noise generated at low speed traveling is prevented, and at high speed traveling, safety traveling is secured prior to others and a state capable of easily generating an alarm is secured.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an inter-vehicle distance warning device that notifies a limit value of the distance between a running vehicle and a metal object immediately in front of the vehicle.

The present invention is used to prevent false alarms due to noise in inter-vehicle distance alarms.

〔overview〕

The present invention provides an inter-vehicle distance warning device that detects the distance between a moving vehicle and a metal object in front of it, and sends out an alarm when the inter-vehicle distance limit corresponding to the traveling speed is exceeded. By disabling the signal and switching the set threshold value between multiple values, it is possible to prevent false warnings due to noise in the following distance warning.

[Conventional technology]

Conventionally, this type of technology was disclosed in Japanese Patent Application Laid-Open No. 57-172849.
As disclosed in , when the distance to the obstacle detected by the ultrasonic pulse becomes less than a predetermined distance, the distance detected from the propagation time of the ultrasonic pulse, the predetermined distance, and the detected distance are calculated. A device that sets the inter-vehicle distance as the smaller of the distance calculated by
No. 8-81840 discloses a device that matches the direction detected by a distance sensor with the steering direction and changes it in accordance with the changing angle of the steered wheels.

[Problem to be solved by the invention]

However, with the above-mentioned conventional technology, there remains the problem that it is not possible to completely distinguish between signals from a vehicle traveling ahead and noise from other surroundings.

The present invention is intended to solve such problems, and an object of the present invention is to provide a device that can remove noise from sources other than the vehicle immediately in front.

[Means to solve the problem]

The present invention provides a radar that detects the distance to a metal object immediately in front of a vehicle as an electrical signal, a speed detection circuit that detects the running speed of the vehicle as an electrical signal, and a radar that detects the distance to a metal object in front of the vehicle as an electrical signal, and A memory circuit in which an inter-vehicle distance limit threshold value is stored in advance, a distance detected by the radar and a traveling speed detected by the speed detection circuit are taken in as input information, and this input information and the threshold value cause the distance to reach a dangerous level. In an inter-vehicle distance warning device equipped with a program control circuit that calculates a short distance and sends out an alarm,
The radar receiving circuit is characterized in that it includes a threshold circuit that invalidates a received signal having a level below a certain threshold, and means for switching the set threshold of the threshold circuit to a plurality of values.

The switching means can be switched automatically according to the speed detected by the speed detection circuit, or can be switched by the driver's operation.

[Effect]

Electrical signals detected by the radar device that are at a level below a certain threshold are disabled, and if the vehicle is traveling at a low speed below a predetermined speed, control is performed by switching to a higher level limit threshold. If the vehicle is traveling at a high speed higher than the specified speed, control is performed by switching to a lower level limit threshold.

With this control, when the noise component in the shaded area shown in Fig. 4(a) is included in the detection radar pulse waveform shown in Fig. 4(a), if the threshold level is set to The time difference A is detected and a false alarm is issued, but by switching the threshold level to ■, the correct time difference B is detected and the occurrence of a false alarm can be prevented.

Furthermore, since the limit threshold value is changed according to the vehicle speed, it is possible to reduce false alarms on general roads and to maintain safety by controlling the system so that warnings are more likely to occur on expressways.

〔Example〕

Next, embodiments of the present invention will be described based on the drawings.

FIG. 1 is a diagram showing a running state of a vehicle equipped with a device according to an embodiment of the present invention.

A radar antenna 2 is installed on the roof of the driver's seat of the vehicle 1, and this radar antenna 2 emits radio waves toward another vehicle 3, which is a metal object, that is traveling in front of the vehicle 1, and connects the vehicles 1 and 3. The distance between vehicles is detected as an electrical signal.

FIG. 2 is a block diagram showing the configuration of an embodiment of the present invention.

The embodiment of the present invention includes a radar device 4 that detects the distance to a metal object immediately in front of the vehicle as an electrical signal, a speed detection circuit 9 that detects the traveling speed of the vehicle as an electrical signal, and a microcomputer 5. The microcomputer 5 includes a memory circuit 11 in which a safe inter-vehicle distance limit threshold value corresponding to the traveling speed of the vehicle is stored in advance, and a distance detected by the radar device 4 and a traveling distance detected by the speed detection circuit 9. It is equipped with a program control circuit 7 that receives the speed as input information, calculates based on this input information and the threshold value that the distance is dangerously short, and sends out a warning, and furthermore, the receiver circuit 41 of the radar device 4 is provided with a program control circuit 7 that calculates that the distance is dangerously short based on this input information and the threshold value, and sends out an alarm. The present invention includes a threshold circuit 42 that invalidates a received signal having a level of , and a threshold switching means 43 that switches the set threshold of the threshold circuit 42 for a plurality of values.

The threshold value switching means 43 includes means for automatically switching according to the speed detected by the speed detection circuit 9 and means for switching according to the driver's operation.

The electrical signal detected from the radar antenna 2 is input to the receiving circuit 41 of the radar device 4, and the threshold circuit 42 of this receiving circuit 4I invalidates the received signal with a level below a certain value. The threshold value switching means 43 switches the threshold level within a predetermined range according to the vehicle speed based on the output of It is directed to an input interface 6 of the computer 5.

The input interface 6 converts this electrical signal into a predetermined information signal level and sends it to the program control circuit 7.

The speed detection circuit 9 detects the traveling speed of the vehicle 1 as an electric signal from a rotating shaft of a transmission (not shown). The electrical signal detected from this speed detection circuit 9 is input to the program control circuit 7 via the input interface 10 of the microcomputer 5. As shown in FIG. 3, a memory circuit 11 connected to the program control circuit 7 stores in advance the safety level and risk level of the running state of the vehicle according to the length of the inter-vehicle distance with respect to the running speed of the vehicle. .

The program control circuit 7 compares and calculates the inter-vehicle distance detected by the radar antenna 2 and the traveling speed detected by the speed detection circuit 9 with the safety degree and danger degree of the traveling state stored in the storage circuit 11, When it is calculated that the driving condition is dangerous, a danger signal is sent to the timer 14 via the output interface 13.

A power supply 15 is connected to the timer 14, and a pilot lamp 17, a warning buzzer 18 which is a sounder, a control input of a solenoid valve 19, and a fourth needle solenoid 22 of a tachograph 21 are connected to its output. This timer 14 and solenoid valve 19
A manual switch 20 is provided between the two.

This manual switch 20 is arranged at the same position as other switches on the driver's seat.

Further, the electric η9 valve 19 opens when a control input is given from the timer 14, and causes compressed air in the air tank 23 to flow into the brake chamber 25 provided in each wheel of the vehicle 1.
to slow down. In addition to the fourth needle solenoid 22, the tachograph 21 also includes a first needle drive device 26 that records the widely known travel speed, and a second needle drive device 27 that records the travel distance.
, and a third hand drive 28 for recording driver changes.

Next, the operation of the apparatus according to the embodiment of the present invention configured as described above will be described.
Let me explain in detail.

The radio waves received by the radar antenna 2 are received by the receiving circuit 41 in the radar device 4, and the threshold circuit 42 receives the radio waves from the predetermined threshold 1.
One received word at the level immediately below is invalidated, and those above it are transmitted to the program control circuit 7 via the input interface 6.

Further, the speed detection circuit 9 constantly outputs the traveling speed to the threshold value switching means 43, and the threshold value switching means 43 receives this output and uses the output to drive at a relatively low speed like when driving on a general road. When the vehicle is running, the threshold level is automatically set to the level (■) shown in FIG. 4, and when the vehicle is traveling at a relatively high speed, such as when driving on an expressway, the threshold level is switched to the level (■) in the figure.

This prevents false alarms due to noise when driving at low speeds, and controls the system to give priority to driving safety at high speeds, making it easier to issue warnings. In this way, the threshold value is automatically changed according to the state of the vehicle speed, and when the inter-vehicle distance becomes dangerous, the program control circuit 7 sends a danger signal to the timer 14 via the output interface 13. This switching can also be performed by the driver's operation.

Under such control, when the vehicle 1 is traveling at the traveling speed v1 shown at point P in FIG. Since it is in the zone, the program control circuit 7 sends a danger signal to the timer 14. At the same time as this danger signal is input, the timer 14 turns on the pilot lamp 17 to inform the driver that the following distance is insufficient and there is a danger.

Additionally, the timer 14 sets a warning buzzer 18 if the driver ignores the lighting of the pilot lamp 170 and continues driving in the danger zone even after one second has elapsed from this point.
A current is applied to the device to emit a buzzer sound.

Furthermore, the timer 14 is activated when the driver continues to drive in the danger zone, ignoring the illumination of the pilot lamp 17 and the sound of the warning buzzer 18 even after 2 seconds have passed since the input of the danger signal. When the manual switch 20 is turned on, a control signal is given to the solenoid valve 19 to close the air tank 2.
3 of compressed air flows into the brake chambers 25 of each wheel, and the vehicle 1 is forcibly braked. Note that when the driver determines that forced braking is unnecessary, he/she may turn off the manual switch 20.

As a result, when the vehicle 1 shifts to the safe zone running state where the vehicle distance is L2 at the running speed v2 shown at point Q in FIG. 3, the danger signal from the program control circuit 7 stops.

At this point, the pilot lamp 17 goes out and the alarm buzzer goes off.
The buzzer 18 stops, and the electromagnetic valve 19 closes, and the compressed air in the brake chamber 25 is discharged to the atmosphere, and the braking action is no longer performed.

When this danger signal is being sent, the tachograph 21
A current is applied to the fourth needle solenoid 22 of the vehicle, which is recorded on a recording paper (not shown) to promote safe operation management after driving.

Note that the start points of the alarm buzzer and the electromagnetic valve described in the above example are not limited to 1 second and 2 seconds after the occurrence of the danger signal, respectively, but can be set to times other than the above-mentioned times by changing the timer settings.

Also, in the above example, when the danger signal is sent to the timer,
Although the example has been shown in which four alarms, the pilot lamp, the alarm buzzer solenoid valve, and the tachograph, operate, any three or less of these four alarms may be used.

Further, in the above example, an example of a warning buzzer is shown as a sounder, but the sounder is not limited to a buzzer, and may be a chime or other sounder.

Further, in the above example, compressed air is flowed into the brake chamber as an example of forced deceleration, but deceleration can also be achieved by forcibly reducing the amount of fuel supplied.

〔Effect of the invention〕

As explained above, according to the present invention, by automatically or manually switching the level of the inter-vehicle distance limit threshold according to the traveling speed of the vehicle, false alarms caused by noise radio waves from sources other than the vehicle traveling in front can be prevented. There is an effect that can be done.

[Brief explanation of drawings]

FIG. 1 is a diagram showing a running state of a vehicle equipped with a device according to an embodiment of the present invention. FIG. 2 is a block diagram showing the configuration of an apparatus according to an embodiment of the present invention. FIG. 3 is a diagram showing the degree of safety and degree of danger of the inter-vehicle distance with respect to the traveling speed stored in the storage device of the embodiment of the present invention. FIG. 4 is a diagram illustrating the influence of noise components of received radio waves. DESCRIPTION OF SYMBOLS 1... Vehicle, 2... Radar antenna, 3... Other vehicle, 4... Radar device, 5... Microcomputer, 6.10... Input interface, 7... Program control Circuit, 9...Speed detection circuit, 11...
Memory circuit, 13... Output ink face, 14...
Timer, 15...Power supply, 17...Pilot lamp, 18...Alarm buzzer, 19...Solenoid valve, 20...
- Manual switch, 21... Tachograph, 22... Fourth needle renoid, 23... Air tank, 25... Brake chamber, 26... First needle drive device, 27...
・Second needle drive device, 28...Third needle drive device, 41・
. . . Receiving circuit, 42 . . . Threshold circuit, 43 . . . Threshold switching means.

Claims (1)

[Claims] 1. A radar that detects the distance to a metal object immediately in front of a vehicle as an electrical signal, a speed detection circuit that detects the running speed of the vehicle as an electrical signal, and a radar that detects the distance to a metal object immediately in front of the vehicle as an electrical signal, and a speed detection circuit that detects the running speed of the vehicle as an electrical signal. The distance detected by the radar and the traveling speed detected by the speed detection circuit are inputted into a memory circuit in which a safe inter-vehicle distance limit threshold value is stored in advance, and the distance is calculated based on this input information and the threshold value. In the following distance warning device, the following distance warning device is provided with a program control circuit that calculates whether the distance is dangerously short and sends out a warning, wherein the radar receiving circuit includes a threshold circuit that disables a received signal at a level below a certain threshold; An inter-vehicle distance warning device characterized by comprising means for switching the set threshold value of the threshold value circuit between a plurality of values. 2. The inter-vehicle distance warning device according to claim 1, wherein the switching means includes means for automatically switching according to the speed detected by the speed detection circuit. 3. The inter-vehicle distance warning system according to claim 1, wherein the switching means includes means for switching by a driver's operation.