KR930002977B1 - Vehicle-passing information detecting apparatus with using optical fiber sensor - Google Patents

Abstract

The device using optical fiber, detects and checks various data on the number of passing cars, running speed, type and weight of a car without interrupting noise rapidly and correctly. The device comprises a detecting section (2) for sensing parameters of vehicle by compressing of steel plate (26) buried under road; light source section (4) for projecting optical power controlled by APC circuit (12) to the section (2); light detecting section (6) for receiving modulated signal transmitted from optical fiber (24) for changing wheel weight to electric signal via upper face of the plate (26).

Description

Vehicle Information Discrimination Device Using Optical Fiber Sensor

1 is a block diagram showing an example of the configuration of the apparatus of the present invention.

2 is a cross-sectional structure diagram illustrating a state in which the present invention is installed on the ground of the road.

3 is a schematic view showing in-plane arrangement of the present invention in a plan view.

4 are diagrams illustrating a case in which vehicle data detected by the apparatus of the present invention is represented by a pulse.

* Explanation of symbols for main parts of the drawings

2: optical fiber detection unit 4: light source unit

6 light detector 8 pulse generator

10: reading processing unit

12: A.P.C (Automatic Power Control) circuit part.

The present invention is to use the optical information sensor of the vehicle using the optical fiber sensor, in particular, using the optical fiber (Optical Fiber) that acts as a sensor to detect and grasp various data regarding the number of passes, speed, weight of the vehicle, shape The present invention relates to a vehicle information discrimination apparatus using an optical fiber sensor.

Existing traffic measuring devices employ a magnetic coil sensor on the roof, and only detect some information such as the quantity and speed of the car, and not detect the weight or type of the car. There is a drawback of not doing it, and because the principle is the magnetic field disturbance method, it is very vulnerable to external disturbances such as engine noise, electric noise, and electric wave disturbance. There is a disadvantage that is greatly affected, it is also a problem that some of the data detection of the vehicle is a lot of trouble.

The present invention was developed after a long research in order to completely solve the above problems, and employs an optical fiber sensor for sensing various vehicle information.

Most optical fiber sensors are modulated by light intensity, but there are external modulations in which optical fibers are used as a tool for transporting light from or to the sensors, or internal modulations that detect changes in transmission characteristics in the optical fibers themselves.

An optical fiber sensor based on internal modulation modulates a parameter under measurement as light is transmitted to the optical fiber. This type of sensor is called an internal modulation sensor.

One of the internal modulation sensors is a microbend loss sensor. Microbands are small optical fiber transverse strains. In optical fiber sensors, microbands are generated by intentional mechanical deformation, and such microbending modulates the light intensity of the receiver by causing radiation from the optical fiber.

In the present invention, by using a high-sensitivity, compact, and strong optical fiber sensor of this principle, the phase is not influenced by noise from external disturbance in the prior art, and exactly the parameters of the vehicle to be detected, that is, the number of cars and It aims to provide a comprehensive understanding of overload vehicles and types of vehicles that are the main causes of road damage as well as speed.

The present invention is a means for achieving the above object, and is embedded in the passage of the vehicle protected by an elastic body installed in the support, the optical fiber sensing unit for sensing the parameters of the vehicle to be detected by the pressure of the upper steel sheet pressure action; And a light source unit that receives optical power stably controlled by an APC (Automatic Power Control) circuit to the optical fiber sensing unit, and an optical fiber that is deformed by the pressure of a wheel to be sensed passing through the pressing steel plate. A light source detector for receiving a modulated signal, a pulse generator for amplifying information data of the detected vehicle detected by the light source detector to generate a pulse-shaped signal, a speed of the vehicle to be detected by pulses generated from the pulse generator, It consists of a reading processing unit that comprehensively grasps the number and the weight and shape of the product.

The above objects and other features and advantages will be more clearly understood by the accompanying drawings and examples. However, the present invention is by no means limited by the following examples and drawings. 1 is a block diagram of the apparatus of the present invention, wherein reference numeral 2 is an optical fiber sensing unit for sensing a vehicle to be detected by the pressure of a wheel. (4) is a light source unit for injecting light into the optical fiber sensing unit (2), (6) a light detecting unit for detecting a modulated signal passing through the optical fiber sensing unit (2) deformed by the pressure of the wheel, (8) A pulse generator for amplifying the information data detected by the photodetector 6 to generate a pulse-like signal, 10 is a speed of the vehicle to be detected by the amplitude, interval, etc. of the pulse generated in the pulse generator 8; It is a reading processing unit that comprehensively reads the quantity, weight, shape, etc.

2 and 3 illustrate a structure in which the optical fiber sensing unit 2 is embedded in the vehicle traffic road R, and the optical fiber sensing unit 2 is located in the middle of the vehicle traffic road R. It is buried in the shape of a child (figure 3).

In addition, as shown in FIG. 2, the optical fiber sensing column 2 has a "U" shape in cross section and is embedded in the ground, and an elastic body 22 installed inside the support 20. ) And an optical fiber 24 disposed in a protected state, and a pressing steel plate 26 mounted horizontally with the road R surface in contact with the upper surface of the elastic body 22. The elastic body 22 is for preventing the damage of the optical fiber 24 at a heavy weight. In addition, the pressing steel plate 26 serves to transmit the weight of the vehicle to the optical fiber 24.

In FIG. 3, the distance d between the optical fibers 24 of the optical fiber sensing unit 2 provided in the road R is arranged such that the distance between the wheels is smaller than that of the nearest car. desirable. This is to detect more detailed information about the vehicle.

In the light source unit 4, a light emitting diode (LED) and a semiconductor laser are used as a light source. This is because the size is small and stable. However, since there is a disadvantage in that the optical power is sensitively changed depending on the temperature, an APC (Automatic Power Control) circuit portion 12 is connected to the light source portion 4, and the light source portion 4 causes the APC circuit portion. The light controlled at (12) is always stably incident on the optical fiber detection unit (2).

In the drawings, reference numerals 23 and 25 denote transmissive lenses, and reference numeral 27 denotes a center separator.

In such a configuration, the light passing through the optical fiber 24 of the optical fiber sensing unit 2 is perfectly symmetrical, and in the same optical fiber 24 waveguide, the doramode moves along the waveguide axis. However, when the optical fiber 24 of the optical fiber sensing unit 2 is deformed by an external pressure (pressure caused by a wheel) and is not uniform, a mode coupling is caused between the optical fiber modes, especially the waveguide mode is an optical fiber. (24) Representation of attenuation of light guided by coupling into a radiation mode, not limited to itself. This light attenuation is increased in proportion to the external pressure action, the signal of the modulated light is detected by the light detection unit 6 connected to the optical fiber detection unit (2).

Based on this principle, it is assumed that a truck (not shown) having three axles passes through the upper surface of the pressing plate 26 of the optical fiber sensing unit 2 of the present invention as shown in FIGS. 2 to 3. In this case, the pressing steel plate 26 is moved to the two-dot chain line position in FIG. 2 while compressing the elastic body 22 positioned to be immediately abutted by the weight of the car. At this time, the optical fiber 24 that is protected and disposed between the elastic bodies 22 is also deformed by the external pressure of the vehicle weight, and is always at the guam fiber 24 side of the optical fiber sensing unit 2 by the light source unit 4. The incident light is modulated by the deformation of the optical fiber 24, and the signal of the modulated light is detected by the photodetector 6. After passing through the vehicle, the steel sheet 26 is returned to its original state by the restoring force of the elastic body 22. The data of the vehicle detected by the photodetector 6 is amplified by pulses as shown in FIG. 4 by the pulse generator 8 connected to the detector 6.

FIG. 4a shows a truck having three axles mounted with the front, middle and rear wheels passing through the optical fiber 24 located at the “A” and “B” points of the optical fiber sensing unit 2 of FIG. Figure 4 shows an example of converting a light-modulated signal detected at a time into a pulse and appearing in one place. FIGS. 4b and c show an example in which the pulses obtained in the same manner as described above are separated from each other in FIG. It is.

By providing the data (pulse), the read processing unit 10 employing the CPU processes and informs the total information about the vehicle to be detected.

In FIG. 4A, the speed of the vehicle to be detected can be measured at the interval l between the pulse and the weight by the pulse width h. For example, if it is faster than the reference speed, the pulse interval (l) becomes relatively narrow, and in the case of a vehicle loaded with a lot of load, the pulse amplitude (h) is higher than the reference amplitude value. have.

The number of pulses can be measured by the number of pulses in Figs. 4B and C, and the distance l 'between the front wheel and the middle wheel and the distance l "between the middle wheel and the rear wheel can be measured. This makes it possible to discriminate the form of the car, that is, a small passenger car, a large bus or a truck.

In the above, the pulse generator 8 and the discrimination processor 10 will not be described separately in this description.

As described above, the present invention makes it possible to grasp the overload vehicle and the type of the car, which has not been known in the past, because the optical fiber is adopted in the vehicle information discrimination system, and also has a low impact on any electrical noise, other materials, and the like. It is an invention having the feature of allowing the vehicle information to be detected quickly and accurately without being received.

Claims (1)

The optical fiber sensing unit is embedded in the vehicle traffic road in a protected state between the elastic bodies 22 installed on the support 20, and detects the parameters of the vehicle to be detected by the pressure plate 26 acting on the upper portion of the elastic body 22 ( 2) and the light source unit 4 which stably injects optical power controlled by the APC circuit unit 12 into the optical fiber sensing unit 2 at any time, and avoids it via the upper surface of the pressing steel plate 26. By providing the data detected from the light source detecting unit 6 which receives the modulated signal output through the optical fiber 24 which is transformed by the wheel pressure of the sensing vehicle, the speed, quantity, weight and shape of the vehicle to be detected can be determined. Vehicle information discrimination device using optical fiber sensor.

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