JP2001021641A - Active distance measuring system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an active distance measuring system by which a distance can be measured quickly and accurately by, instead of a distance measurement by a conventional reflection system receiving only two kinds of different propagating mediums for distance measurement in a preceding object. SOLUTION: In this active distance measuring system which measures the separation distance between two movable objects, a transmitter 2 is mounted on a vehicle 1 to be distance-measured. An optical transmitter which transmits light 6, an ultrasonic transmitter which transmits ultrasonic waves 7 whose propagation speed is slower than that of the light 6 and a transmission control part are provided at the transmitter 2. On the other hand, a receiving and distance-between-vehicles measuring device 11 is mounted on a distance measuring vehicle 10. An optical receiver and an ultrasonic receiver are provided at the receiving and distance-between-vehicles measuring device 11. On the basis of the difference between the receiving time of the light 6 by the optical receiver and the receiving time of the ultrasonic waves 7 by the ultrasonic receiver the separation distance between the vehicle 1 to be distance-measured and the distance measuring vehicle is measured quickly and accurately.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an active distance measuring system for measuring the distance between two moving bodies moving in the same direction, particularly, the distance between vehicles.

[0002]

2. Description of the Related Art Conventionally, in order to measure the distance between two vehicles, for example, as shown in FIG. The distance 101 between the two vehicles is measured by measuring the time required for the reflected wave from the preceding vehicle B to reach the vehicle A.
Was to be measured.

That is, the distance 1 is measured from the time until the ultrasonic wave 101 is emitted and the reflected wave is detected (hereinafter, referred to as a reflection method).

[0004]

However, in the above-described conventional distance measuring system, the ultrasonic wave 101 emitted from the vehicle A propagates in the air and is strongly attenuated when reflected from the vehicle B. There is a problem that it is difficult to accurately measure a distance.

Another problem is that when there are a plurality of preceding vehicles in addition to the vehicle B, the vehicle whose distance has been measured cannot be specified.

The present invention eliminates the above-mentioned problems, and replaces the conventional reflection-based distance measurement with the preceding object.
It is an object of the present invention to provide an active distance measuring system capable of quick and accurate distance measurement by only receiving two different propagation media for distance measurement.

[0007]

Means for Solving the Problems [1] In an active distance measuring system for measuring a distance between two movable objects, a first distance measuring propagation medium mounted on a subsequent first object is transmitted. Means for transmitting a second distance-measuring propagation medium having a slower propagation speed than the first distance-measuring propagation medium mounted on the first object; Means for receiving the first distance-measuring propagation medium, and a second distance-measuring propagation medium having a lower propagation speed than the first distance-measuring propagation medium mounted on the second object. Means for receiving, the second object and the second object based on a difference between a reception time of the first distance measurement propagation medium and a reception time of the second distance measurement propagation medium in the second object. And means for measuring the distance between the objects.

[2] In the active distance measuring system according to the above [1], the first distance measuring propagation medium is light, and the second distance measuring propagation medium is an ultrasonic wave.

[3] In the active distance measuring system according to the above [1], the first distance measuring propagation medium is a radio wave, and the second distance measuring propagation medium is an ultrasonic wave.

[4] In the active distance measuring system according to the above [1], the object is a vehicle.

[5] In the active distance measuring system according to the above [1], the object is a moving object conveyed on a conveying belt.

[0012]

Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 1 is a schematic diagram of an active distance measuring system showing a first embodiment of the present invention, and FIG. 2 is a block diagram of the active distance measuring system.

In these drawings, reference numeral 1 denotes a vehicle to be measured, and the transmitting device 2 is mounted on the vehicle 1 to be measured. The transmitting device 2 includes an optical transmitter 3, an ultrasonic transmitter 4, and a transmission controller 5, and is configured to simultaneously emit light 6 and ultrasonic wave 7, which are two different types of propagation media for distance measurement. Have been. The speed of light is approximately 3 × 10 ⁸ m / sec, and the ultrasonic wave has a frequency (frequency) above the audible range, ie, 2000
It is a sound wave of 0 Hz or more.

On the other hand, the distance measuring vehicle 10 receives the light 6 and the ultrasonic wave 7 which are the two types of propagation mediums for distance measurement emitted from the vehicle 1 to be measured and receives and measures the distance between the vehicles. The device 11 is mounted. This reception / inter-vehicle distance measuring device 11
Is equipped with an optical receiver 12, an ultrasonic receiver 13, and a reception / vehicle distance calculation unit 14, and the reception / vehicle distance calculation unit 14 calculates the arrival time of the light 6 and the ultrasonic wave 7, and furthermore, The distance between the to-be-measured vehicle 1 and the to-be-measured vehicle 10 is measured based on the arrival time difference between the light 6 and the ultrasonic wave 7. That is, active distance measurement between movable vehicles can be performed.

With this configuration, according to the first embodiment, the light 6 and the ultrasonic wave 7, which are two types of propagation media for distance measurement, emitted from the vehicle 1 to be measured, are transmitted to the vehicle 10 by distance measurement. The distance between the two vehicles can be measured only by the reception and the inter-vehicle distance measuring device 11 receiving the difference between the arrival times of the light 6 and the ultrasonic waves 7.

Therefore, as compared with the conventional reflection method, attenuation of light and ultrasonic waves at the time of reflection can be eliminated, and quick and accurate measurement of the distance between vehicles can be performed.

In the above embodiment, the inter-vehicle distance between the two vehicles is described. However, it is needless to say that the inter-vehicle distance between the two vehicles can be measured even when one of the vehicles is stopped. .

If one or both of light and ultrasonic waves are modulated and an ID is entered, the vehicle 1 to be measured can be specified.

FIG. 3 is a schematic diagram of an active distance measuring system showing a second embodiment of the present invention, and FIG. 4 is a block diagram of the active distance measuring system.

In these figures, reference numeral 1 denotes a vehicle to be measured, and the transmitting device 2 is mounted on the vehicle 1 to be measured. The transmitting device 2 is equipped with a radio transmitter 21, an ultrasonic transmitter 4, and a transmission controller 22, and is configured so that two different types of propagation media for distance measurement, a radio wave 23 and an ultrasonic wave 7, are simultaneously emitted. Have been.

On the other hand, the ranging vehicle 10 receives the radio waves 23 and the ultrasonic waves 7 which are two types of propagation mediums for ranging emitted from the ranging vehicle 1, and measures the distance between the vehicles. The measuring device 11 is mounted. The reception / inter-vehicle distance measurement device 11 includes a radio wave receiver 24, an ultrasonic receiver 13,
The inter-vehicle distance calculation unit 14 is mounted, and the arrival time of the radio wave 23 and the ultrasonic wave 7 is obtained. Further, based on the arrival time difference between the radio wave 23 and the ultrasonic wave 7, the distance measurement vehicle 1 and the distance measurement vehicle are measured. The distance between the vehicles 10 is measured. That is,
Active ranging between movable vehicles can be performed.

With this configuration, according to the second embodiment, the radio waves 23 and the ultrasonic waves 7, which are two types of propagation media for distance measurement, radiated from the vehicle 1 to be measured are transmitted by the distance measurement vehicle 10. The distance between the two vehicles can be measured only by receiving and determining the arrival time difference between the radio wave 23 and the ultrasonic wave 7.

Therefore, compared with the conventional reflection system, attenuation of radio waves and ultrasonic waves at the time of reflection can be eliminated, and
Quick and accurate measurement of the following distance can be performed.

FIG. 5 is a schematic diagram of an active distance measuring system according to a third embodiment of the present invention.

In this embodiment, the belt conveyor 3
The distance between the succeeding first product 31 conveyed at 0 and the preceding second product 41 is measured. In that case,
A transmitting device 32 that emits two types of distance measuring propagation media, light 6 and ultrasonic wave 7 or radio wave 23 and ultrasonic wave 7, which are emitted to the subsequent first product 31, is attached, and the preceding second The product 41 receives the light 6 and the ultrasonic wave 7 or the radio wave 23 and the ultrasonic wave 7 and mounts a reception / inter-vehicle distance calculation device 42 having a reception / inter-vehicle distance calculation unit for calculating an inter-vehicle distance. I have.

Accordingly, the distance between the first product 31 and the preceding second product 41 is monitored, and when the preceding second product 41 stops, the distance becomes shorter and an alarm is issued. Or when there is a risk of collision, automatic control such as stopping the belt conveyor 30 can be performed.

If one or both of radio waves and ultrasonic waves are modulated and an ID is entered, the subsequent first product 31 can be specified.

It is desirable to use directional light, radio waves, and ultrasonic waves as the propagation medium for distance measurement in the above embodiment. In particular, when a transmitting device and a receiving and inter-vehicle distance measuring device are mounted on a single vehicle or product, the distance measuring propagation medium is provided with directivity to prevent interference between the two.

Further, the present invention is not limited to the above embodiments, but various modifications are possible based on the spirit of the present invention, and these are not excluded from the scope of the present invention.

[0031]

As described above in detail, according to the present invention, since the reflection method is not employed unlike the prior art, there is no attenuation at the time of reflection of the distance measuring propagation medium, so that it is quick and accurate. It is possible to measure the distance between any two objects.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of an active distance measuring system according to a first embodiment of the present invention.

FIG. 2 is an active ranging system block diagram showing a first embodiment of the present invention.

FIG. 3 is a schematic diagram of an active distance measuring system according to a second embodiment of the present invention.

FIG. 4 is an active ranging system block diagram showing a second embodiment of the present invention.

FIG. 5 is a schematic diagram of an active distance measuring system according to a third embodiment of the present invention.

FIG. 6 is a schematic diagram of a conventional active distance measuring system.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Vehicle to be measured 2, 32 Transmitting device 3 Optical transmitter 4 Ultrasonic transmitter 5, 22 Transmission control unit 6 Light 7 Ultrasonic 10 Distance measuring vehicle 11, 42 Receiving / inter-vehicle distance measuring device 12 Optical receiver 13 Ultrasonic Receiver 14 Receiving / inter-vehicle distance calculation unit 21 Radio wave transmitter 23 Radio wave 24 Radio wave receiver 30 Belt conveyor 31 First product 41 Second product

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Claims (5)

[Claims] 1. An active distance measuring system for measuring a separation distance between two movable objects, comprising: (a) means for transmitting a first distance measuring propagation medium mounted on a subsequent first object; (B) means for transmitting a second distance-measuring propagation medium having a slower propagation speed than the first distance-measuring propagation medium mounted on the first object; and (c) a preceding second object. Means for receiving the first distance-measuring propagation medium mounted on
(D) means for receiving a second distance-measuring propagation medium having a slower propagation speed than the first distance-measuring propagation medium mounted on the second object; and (e) in the second object. The first
Means for measuring the distance between the second object and the first object based on the difference between the reception time of the distance measurement propagation medium and the reception time of the second distance measurement propagation medium. An active distance measuring system, characterized in that: 2. The active distance measuring system according to claim 1, wherein said first distance measuring propagation medium is light, and said second distance measuring propagation medium is an ultrasonic wave. Distance measuring system. 3. The active distance measuring system according to claim 1, wherein said first distance measuring propagation medium is a radio wave, and said second distance measuring propagation medium is an ultrasonic wave. Distance measuring system. 4. The active ranging system according to claim 1, wherein said object is a vehicle. 5. The active distance measuring system according to claim 1, wherein the object is a moving object conveyed on a conveying belt.