JPH08315276A - Device for detecting vehicle approaching from the rear - Google Patents

Abstract

PURPOSE: To detect a vehicle or a person approaching even when there are many obstacles by providing a vehicle-side transmission equipment which outputs a signal of the frequency band of a long wave or, intermediate wave by radio, a portable transmission and reception equipment, and a vehicle-side reception equipment which outputs an alarm signal. CONSTITUTION: The vehicle-side trarsmission equipment 3 is equipped with a transmitter 8 which outputs a modulated signal L of specific frequency in the frequency band of the long wave or intermediate wave. The vehicle-side reception equipment 4 is equipped with a receiver 10 which receives the detection signal D from the portable transmission and reception equipment 6 through a directional antenna 9 installed so as to have directivity toward behind a truck 1. This receiver 10 outputs the alarm signal A to a main body device 5 when the level of the detection signal D received through the antenna 9 exceeds a specified threshold value D0. Then, the control board 11 of the main body device 5 supplies the output timing of the modulated signal L periodically to the transmission equipment 3 and outputs the alarm signal A to an alarm 12 when the detection signal D is inputted to the reception equipment 4 in a corresponding specified timing, thereby outputting an alarm.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an approach detecting device at the rear of a vehicle for detecting whether or not a person is present near the rear of a vehicle such as an automobile. The present invention relates to those suitable for use in places where detection is difficult.

[0002]

2. Description of the Related Art As a conventional vehicle rear approach detecting device, as disclosed in, for example, Japanese Patent Laid-Open No. 57-55242,
2. Description of the Related Art There is known a device that irradiates an ultrasonic wave from the rear of a vehicle, detects the presence of a vehicle or other obstacle nearby by the reflected wave, and outputs an alarm. However, such a device has the following problems in the field of use of the present invention. In a place such as a construction site where there are many obstacles such as embankments and construction materials, the approach detection state due to various obstacles frequently occurs, and it is not useful for preventing the most injured accident that should be avoided. The number of ultrasonic detectors that have been put into practical use is 5
Although detection of short distances within m is the main focus, approach detection at a distance of more than 5 m is necessary for reliable prevention of personal injury. The ultrasonic detecting device is not suitable for use in a place such as a construction site where tainting of a vehicle is unavoidable, because a significant deterioration in function is recognized when dirt such as mud adheres to the sensor part. When ultrasonic waves hit flexible objects such as clothes,
The level of the absorbed and reflected signal is significantly reduced, and it is not possible to accurately detect the approach of a person.

On the other hand, for example, Japanese Patent Laid-Open No. 63-1455.
As disclosed in Japanese Patent Publication No. 95, a device is known in which a transmitter provided in a vehicle sends a signal including ultrasonic waves, light, or electromagnetic waves, and a receiver carried by a person receives the signal and outputs an alarm. ing. In such a device, since the target of detection is limited to the person who carries the receiver, it is effective in preventing personal injury, but when ultrasonic waves or light is used as a signal, the above problems cannot be solved at all, Moreover, even if the human body is located between the vehicle and the portable receiver,
It is not practical because the receiver must always be carried toward the vehicle. On the other hand, when electromagnetic waves are used as signals, there is a problem that the approach distance cannot be accurately detected by the conventionally known distance detection method using electromagnetic waves. That is, as a conventional distance detection method using electromagnetic waves, for example, Japanese Patent Laid-Open No.
The one described in Japanese Patent Laid-Open No. 2-205497 is known, but in this method, weak radio waves in the ultra-high frequency band are used to try to identify the distance between the transmitter and the receiver by the reaching distance. However, depending on the conditions such as obstacles existing between the two, an error of the detection distance of 10 m unit occurs. Moreover, according to the method disclosed in Japanese Patent Laid-Open No. 63-145595, the alarm is output only on the receiver side, and it is not possible to call the attention of the vehicle driver.

[0004]

SUMMARY OF THE INVENTION Therefore, the object of the present invention is to reliably detect the approach of a vehicle and a person even in a place where there are many obstacles such as a construction site, and to the rear of the vehicle driver. The point is whether a device that can reliably prevent a personal injury will be obtained by outputting an approach warning. And 20m to solve such a problem
There is a need for a means capable of accurately detecting a distance within a relatively short range within.

[0005]

SUMMARY OF THE INVENTION The present invention is a vehicle rear approach detection apparatus for detecting whether or not a person is present near the rear of a vehicle, which is attached to the vehicle and has a long wave or medium wave at a predetermined output level. A vehicle-side transmitter that wirelessly outputs a signal in the frequency band of a wave and a person who is a target of approach detection are carried by the vehicle-side transmitter in an inductive coupling relationship to receive the signal. If the signal is equal to or higher than a predetermined level, the portable transceiver that wirelessly outputs a detection signal having a frequency different from the signal and an antenna that is attached to the vehicle and has directivity toward the rear of the vehicle receive the detection signal, and the received signal is received. If the detection signal is equal to or higher than a predetermined level, a vehicle-side receiving device that outputs an alarm signal to an actuating device such as an alarm is provided to solve the above problems.

If the vehicle-side transmitter and the vehicle-side receiver are activated when the vehicle is moving backward, the approach can be detected only when the vehicle is moving backward and the unnecessary warning signal is issued. There is no output.

The vehicle-side transmitter and the vehicle-side receiver operate by using a battery installed in the vehicle as a power source, and if serial data is transmitted and received between them via a power line, wiring on the vehicle side is performed. Can be simplified.

Further, the portable transmitter / receiver can activate an alarm device attached thereto when the signal from the vehicle-side transmitter is at a predetermined level or higher to output an alarm to a person approaching the vehicle.

[0009]

The signal wirelessly output from the vehicle-side transmitting device is received by the portable transmitting / receiving device that is inductively coupled to the transmitting device, and the signals are exchanged mainly between them by an induction electric field or an electrostatic field. This signal is in the long-wave or medium-wave frequency band (30 KHz to 3 MHz) and its wavelength (10
It shows a sharp attenuation (attenuation in inverse proportion to the square or cube of the distance) at a relatively short distance of about 20 m, which is much shorter than 0 m or more). Therefore, even if various obstacles are present on the way and are affected by signal reflection, etc., they do not become large enough to affect the rapid attenuation, and the level of the signal (field strength ) To confirm the degree of attenuation, the distance from the vehicle-side transmitter can be detected with a small error, and the approach between the two can be reliably detected.

Further, since the signal in the frequency band of long wave or medium wave is used, even if there are obstacles such as working machines, materials, and embankment at the construction site, there is no problem with the wavelength. Since it is small, it can be reliably received by the detection-side transmitting / receiving device without being blocked by the obstacles.

Then, the approach of the vehicle and the person detected in this way can be notified to the vehicle-side receiving device, and an alarm can be output on the vehicle side. Moreover, since this detection signal is received with directivity toward the rear of the vehicle, it is possible to output an alarm only for approaching to the rear, which is a blind spot for the vehicle driver.

[0012]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is an explanatory view showing the arrangement of the embodiment, and shows an example in which the present invention is carried out so that an accident does not occur between a truck 1 coming in and going out and workers 2A to 2D working on the site at a construction site. ing. In a truck 1 as a vehicle, a transmitter 3 is attached to the ceiling of a driver's cab, a receiver 4 is attached to a rear bumper, and a transmitter 5 and a main unit 5 connected to the receiver 4 are attached to the driver's cab. ing. On the other hand, the transmitter / receiver 6 is carried by the worker 2 who is the object of approach detection.

FIG. 2 is a block diagram showing the configuration of the embodiment. The vehicle-side transmitter 3 includes a transmitter 8 that outputs a modulated signal L of a predetermined frequency (for example, 150 KHz) in a long-wave or medium-wave frequency band (preferably 500 KHz or less) via the loop antenna 7. . The loop antenna 7 is installed so that the loop is horizontal with respect to the track 1, and forms a magnetic field orthogonal to the loop in the front, rear, left, and right directions. The loop antenna 7 has a conductor with a diameter of 20 to 30.
It is composed of 1 to 3 turns in a circle of cm, and the frequency used for this is in the long wave or medium wave frequency band, for example, 1
If the frequency is 50 KHz, the wavelength becomes 2000 m, and since the antenna 7 is much smaller than the wavelength, the electromagnetic wave radiation inherent to the antenna is hardly recognized. Therefore,
A magnetic field for proximity detection can be formed without irradiating unnecessary electromagnetic waves to the outside.

The modulated signal L is preferably 500 KHz or less. This type of system needs to be easily usable by anyone without requiring a special license, and for this purpose, it is necessary to avoid high-frequency, high-power electromagnetic radiation that is regulated by the Radio Law. On the other hand, the attenuation of the magnetic field induced by the loop antenna 7 is being detected for the approach detection, and if the detection distance is widened, a certain high antenna output is required. As a result of investigating and testing from such a need, if a relatively low frequency signal of 500 KHz or less is used, even if the output is relatively increased, it is not regulated by the Radio Law, and even if it is separated from the antenna 7 by 10 m or more, the signal is surely obtained. It turned out to be detectable.

The vehicle-side receiving device 4 comprises a receiver 10 which receives a detection signal D from the portable transmitting / receiving device 6 via a directional antenna 9 installed so as to have a directivity toward the rear of the truck 1. ing. Although various antennas are already known as the directional antenna 9, the widely used Yagi antenna or the like has a wide two-dimensional shape and protrudes to the rear of the track 1.
A cylindrical slot antenna in which a slot parallel to the axial direction is opened in a metal cylinder of 8 or less is used. As a result, the directional antenna can be made up of a thin metal pipe, so that it can be easily attached to a bumper or the like. As the detection signal D, in order to make the directional antenna 9 as compact as possible, a signal having a predetermined frequency (for example, 300 MHz) selected from a frequency band (30 MHz to 3 GHz) of an ultra-short wave or an ultra-short wave having a short wavelength is used. Receiver 10
Then, if the detection signal D received via the antenna 9 has a level exceeding a predetermined threshold value D0, the main unit 5
The alarm signal A is output to.

The main unit 5 comprises a control board 11 and an alarm device 1.
2 is provided. The control board 11 has a microcomputer, and periodically outputs the output timing of the modulation signal L to the transmitting device 3, and when the detection signal D is input to the receiving device 4 at a predetermined timing in response to this, outputs to the alarm device 12. An alarm signal A is output and an alarm is output. The alarm device 12 includes an audio output unit that outputs an alarm sound and a display unit that blinks an alarm lamp, and outputs an alarm both visually and visually.

The portable transmitter / receiver 6 detects the approach based on the receiver 13 that receives the modulated signal L from the transmitter 3, the transmitter 14 that outputs the detection signal D, and the signal L received by the receiver 13. The controller 16 provides the detection signal D output from the transmitter 14 and the alarm output from the connected alarm device 15. The receiver 13 includes a bar antenna 17 formed of a ferrite core coil, and detects the magnetic field generated by the loop antenna 7 of the transmitter 3. On the other hand, the transmitter 14 uses a loop antenna 18 having a pattern printed on a printed circuit board and outputs the above-mentioned electromagnetic wave of relatively high frequency (for example, 300 MHz) as the detection signal D.

FIG. 3 is an explanatory view showing a wiring example of the embodiment apparatus in the track 1. The transmitting device 3, the receiving device 4, and the main body device 5 provided on the truck 1 side are all provided with a battery 19 and a power supply line 20 provided on the truck 1.
Is connected through and is getting power. Further, the receiving device 4 and the main body device 5 are arranged apart from each other on the front and rear sides of the track 1, but serial data is transmitted and received between them via the power supply line 20, and it is necessary to connect them again with a signal line. Wiring is easy without

Reference numeral 21 is a cigarette lighter socket provided on the side of the truck 1 for connecting the main body device 5 and the power supply line 20. Reference numeral 22 is a back lamp of the truck 1, 23 is a lighting switch of the back lamp 22, the receiving device 4 is connected in parallel with the back lamp 22, and when the truck 1 enters the back gear, the lighting switch 23 causes the receiving device 4 of the back lamp 22. At the same time, it becomes energized.

FIG. 4 shows the control board 11 in the main unit 5.
5 is a flowchart illustrating a main part program of FIG. The operation of the embodiment will be described below with reference to this figure.

When the truck 1 is put in the back gear for the backward movement, the main body apparatus 5 is notified that the receiving apparatus 4 is energized and the backward movement is started. When receiving the notification from the receiving device 4 (1), the main body device 5 sends a signal L to the transmitting device 3.
The transmission command of is output (2).

Upon receiving the transmission command in step (2), the transmitter 3 outputs the modulated signal L from the loop antenna 7. Here, the output level of the signal L to be transmitted is set to two levels of high and low (L1 and L2), and the signal is output at the high level L1 during the first transmission immediately after the gear is put in the back gear, and the next low level. The output level is alternately raised and lowered such as outputting at L2. This output level L1 ・ L2
Is set according to the distance to be detected, and in this embodiment, if there is a response of the detection signal D to the level L1, the approach is within 10 m, and if there is a response to the level L2, the approach is within 5 m. The level is set so that you can judge that.

The control board 11 confirms whether or not the detection signal D is received by the receiving device 4 within the predetermined time T after the output of the transmission command in step (2) (3) (4). Here, if the receiving device 4 does not receive the detection signal D exceeding the threshold value D0, it is determined that there is no approaching person behind the track 1, and such a determination is performed a predetermined number N (for example, twice).
However, if the alarm device 12 is outputting an alarm, the alarm output is stopped (6) and the process returns to step (1).

When the detection signal D exceeding the threshold value D0 is received in the steps (3) and (4), it is first confirmed whether the output level of the transmitter 3 is L1 or L2 (7), and each level is checked. Confirm that the detection of the number of times has continued for the predetermined number of times N (8) (1
0), if it is recognized as continuous, the alarm 12 outputs the alarms A1 and A2 according to the output levels L1 and L2 (9) (1
1). Alarms A1 and A2 can be changed by changing the tone and pattern of voice output and the blinking pattern of the alarm lamp.
It reports the existence of an approaching person at the stage.

FIG. 5 is a flow chart for explaining a main program of the controller 16 in the portable transmitter / receiver 6.

The receiver 13 is constantly in a state of receiving the signal L from the transmitting device 3, and when the level (electric field strength) of the received signal exceeds a predetermined threshold value D1 (21), the track It judges that it is approaching within the predetermined distance to 1,
The detection signal D is output from the transmitter 14 (22). If the output of the detection signal D is continuously performed a plurality of times within a constant time T1 that is slightly longer than the transmission cycle of the signal L (23), the transceiver device 6
Is judged to be within the alarm range and the alarm device 15 outputs an alarm (24). In step (21), if the signal L of the predetermined level or more is not received and this state continues for the predetermined time T1 or more (25), it is determined that the alarm range is not approached, and the alarm device is issued. If 15 is outputting an alarm, this is stopped (26).

The signal L from the transmitter 3 is alternately output at two output levels L1 and L2, each of which has a characteristic as shown in FIG. The receiver 13 detects the signal L of any output level by comparing it with the common threshold value D1 without distinguishing it. However, the transmitting / receiving device 6 can issue an alarm in response to the lower output level L2 by issuing an alarm on the condition that the transmission / reception device 6 continues a plurality of times within a constant time T1 which is slightly longer than the transmission period of the signal L. . That is, since both of the output levels L1 and L2 are in the detection state, an alarm is output in response to being in the closer approach range according to the output level L2, and the work of carrying the transmitter / receiver device 6 is carried out. Frequent alarms are output to those who do not interfere with work.

The actual operation of the embodiment having the above construction will be described with reference to the example of FIG. 1. When the truck 1 moves backward, the transmitter 3 alternately transmits the signals L1 and L2, and the signal L1 is transmitted. The detection signals D are output from the four transceivers 6 carried by the workers 2A to 2D to the signal L2.
On the other hand, the detection signal D is output from the two transceivers 6 of the workers 2A and 2D. In the receiving device 4, the worker 2A, who is in the receiving range of the directional antenna 9 among these detection signals,
The signal from 2B is received and the alarm signal A is output. Here, since the worker 2A is within the detection range of the signal L2, the alarm A2 is output from the alarm device 12 and the worker 2A near the truck 1 -Alarm is also output from the transmitter / receiver 6 of 2B. If the worker 2A withdraws from the rear of the truck 1 by the alarm output from the transmitter / receiver 6, it is assumed that the worker 2B is now in the detection range of the signal L1 and the alarm device 12
Switches to the output of alarm A1.

As described above, according to this embodiment, it is possible to accurately detect the presence of an operator behind the truck 1 and notify the driver of the truck, and not only to the rear of the truck 1 but also to the near side. An alarm can be output to the worker who is present from the transceiver 6 to notify the approach, and an accident can be reliably prevented. In addition, the driver of truck 1 has alarm A
The degree of approach of the worker to the rear can be known from 1 · A2, and if the retreat speed is controlled accordingly, the work can be carried out safely and efficiently.

[0030]

As is apparent from the above description, compared to the conventionally known ultrasonic type proximity detecting device, it is possible to detect the proximity at a distance exceeding 5 m which is the range required for preventing personal injury, and The distance from the vehicle-side transmitter to the surrounding people can be detected without causing a large error like the distance detection using the electromagnetic waves in the above, and it is possible to reliably detect the approach of the two and output an alarm signal, thus preventing personal injury. You can make a great contribution. Further, it is possible to notify the vehicle-side receiving device of the detected approach of the vehicle and the person, and to give an alarm signal to the vehicle side, and by promoting deceleration or stopping on the vehicle side, more reliable accident prevention can be performed. Become. Moreover, since the approach detection signal is received with a directivity toward the rear of the vehicle, the warning signal can be output only for the approach to the rear, which is a blind spot for the vehicle driver, and an unnecessary warning is issued. There is no need to worry about diminishing attention.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing a usage state of an embodiment.

FIG. 2 is a block diagram showing a configuration of an example.

FIG. 3 is an explanatory diagram showing a wiring example of the embodiment apparatus in the track 1.

FIG. 4 is a flowchart illustrating a main program of a control board 11 in the main body device 5.

5 is a flowchart illustrating a main program of a controller 16 in the mobile transceiver device 6. FIG.

[Explanation of symbols]

 1 Vehicle Truck 2A to 2D Workers to be Detected 3 Vehicle-Side Transmitter 4 Vehicle-Side Receiver 5 Main Unit 6 Portable Transmitter / Receiver 7 Loop Antenna 9 Directional Antenna 11 Control Board 12 Alarm Device 19 Vehicle Battery 20 Power Line

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Shoichi Takeda 1825, Amamiya, Sarahaku, Nagano Prefecture, inside MK Seiko Co., Ltd. ) Inventor Masahiko Hayashibe 1825 Amamiya, Sarahaku, Nagano Prefecture, MK Seiko Co., Ltd. (72) Inventor, Isamu Yoshizawa 1825, Amamiya, Sarahaku, Nagano Prefecture

Claims (4)

[Claims] 1. A vehicle rear approach detection apparatus for detecting whether or not a person is present near the rear of a vehicle, which is attached to the vehicle and wirelessly transmits a signal in a long wave or medium wave frequency band at a predetermined output level. When the vehicle-side transmitter that outputs the signal is received by the person who is the object of approach detection and has an inductive coupling relationship with the vehicle-side transmitter, and the received signal is equal to or higher than a predetermined level. A portable transceiver that wirelessly outputs a detection signal having a frequency different from the signal, and an antenna that is attached to the vehicle and has directivity toward the rear of the vehicle receive the detection signal, and the received detection signal must be at a predetermined level or higher. A vehicle rear approach detection device, comprising: a vehicle-side receiving device that outputs an alarm signal to an operating device such as an alarm device. 2. The vehicle rear approach detection device according to claim 1, wherein the vehicle side transmitter and the vehicle side receiver are activated when the vehicle moves backward. 3. The vehicle rear approach detection device according to claim 1, wherein the vehicle-side transmitter and the vehicle-side receiver are
A vehicle rear approach detection device, which operates using a battery mounted on a vehicle as a power source and exchanges serial data between the two via a power line. 4. The vehicle rear approach detection device according to claim 1, wherein the portable transmitter / receiver device activates an attached alarm device when a signal from the vehicle-side transmitter device is equal to or higher than a predetermined level. Rear approach detection device.