阅读说明：本技术 一种光纤光栅车辆动态称重传感器、装置及方法 (Fiber grating vehicle dynamic weighing sensor, device and method ) 是由 于淼 程立耀 崔洪亮 王忠民 罗政纯 杨先进 杨先勇 吴崇坚 郑志丰 于 2020-05-09 设计创作，主要内容包括：本发明提供了一种光纤光栅车辆动态称重传感器、装置及方法,包括：上方开口的壳体,和与壳体的上方开口连接的应变片；壳体内壁设置有若干个悬臂梁,悬臂梁的一端与壳体内壁连接,悬臂梁的另一端为自由端；应变片的顶面的中心设有凸起,底面的中心与传动杆的一端连接,传动杆的另一端与悬臂梁的自由端接触；悬臂梁与光纤光栅连接。还提供了一种光纤光栅车辆动态称重装置,包括：基座,所述基座上安装若干个动态称重传感器,所述称重传感器的顶部与称重板配合连接；解决了光纤称重传感结构的重心偏移问题,可对传感器组进行单个称重传感器的更换,方便后期维护。(The invention provides a fiber grating vehicle dynamic weighing sensor, a device and a method, comprising the following steps: the upper opening of the shell is connected with the strain gauge; the inner wall of the shell is provided with a plurality of cantilever beams, one ends of the cantilever beams are connected with the inner wall of the shell, and the other ends of the cantilever beams are free ends; the center of the top surface of the strain gauge is provided with a bulge, the center of the bottom surface is connected with one end of the transmission rod, and the other end of the transmission rod is contacted with the free end of the cantilever beam; the cantilever beam is connected with the fiber grating. Still provide a fiber grating vehicle dynamic weighing device, include: the weighing system comprises a base, a weighing plate and a plurality of weighing sensors, wherein the base is provided with a plurality of dynamic weighing sensors, and the tops of the weighing sensors are connected with the weighing plate in a matching way; the problem of the focus skew of optic fibre sensing structure of weighing is solved, can carry out single weighing sensor's change to the sensor group, make things convenient for later maintenance.)

1. A fiber grating vehicle dynamic weighing sensor, comprising: the upper opening of the shell is connected with the strain gauge; the inner wall of the shell is provided with a plurality of cantilever beams, one ends of the cantilever beams are connected with the inner wall of the shell, the other ends of the cantilever beams are free ends, and the middle sections of the cantilever beams are connected with the fiber bragg grating; the center of the top surface of the strain gauge is provided with a bulge, the center of the bottom surface of the strain gauge is connected with one end of the transmission rod, and the other end of the transmission rod is contacted with the free end of each cantilever beam.

2. The dynamic load cell of claim 1, wherein the inner wall of the housing is connected to one end of a plurality of first and second cantilevered beams, the free end of the first cantilevered beam contacting the actuator rod; the free end of the second cantilever beam is connected with the heavy block; the first cantilever beam is connected with the first fiber bragg grating, and the second cantilever beam is connected with the second fiber bragg grating.

3. The dynamic load cell of claim 1, wherein said protrusion has a curved surface in the shape of a circular arc.

4. The dynamic load cell of claim 1, wherein said cantilever beam is an equilateral trapezoidal beam, and said fiber grating is adhered to a surface of the cantilever beam in an axial direction.

5. The dynamic load cell of claim 1, wherein the housing is further coupled to a temperature-compensated fiber grating, the temperature-compensated fiber grating being coupled to the first fiber grating in an unstressed state via an optical fiber.

6. A fiber grating vehicle dynamic weighing device, comprising: a base, wherein a plurality of dynamic weighing sensors as claimed in any one of claims 1 to 5 are mounted on the base, and the tops of the weighing sensors are connected with a weighing plate in a matching way; the base comprises a plurality of sensor mounting holes, and a set distance is reserved between the two sensor mounting holes; and the center of the lower surface of the weighing plate is provided with a groove structure matched with the bulge of the stress sheet.

7. The dynamic weighing apparatus of claim 6, further comprising a fiber grating demodulator, the fiber grating of each weighing sensor being connected to the fiber grating demodulator via an optical fiber; the sensor mounting hole is used for mounting dynamic weighing sensors, a through hole used for placing an optical fiber jumper is further formed in the bottom of the sensor mounting hole, and the optical fiber jumper connects the weighing sensors to achieve light path communication.

8. The dynamic weighing apparatus of claim 6, wherein the junction of the load cell and the base is sealed by a gasket seal.

9. A fiber grating vehicle dynamic weighing method, wherein the vehicle weighing is performed by using the dynamic weighing apparatus according to any one of claims 6 to 8, and the steps comprise:

measuring the drift amount of the reflection wavelength of each fiber grating in real time through a fiber grating demodulator, and calculating to obtain the weight value and the vibration data measured by each weighing sensor;

and carrying out whole vehicle analysis on the measured weight value and the vibration data, and obtaining the wheel weight, the axle weight, the whole vehicle weight, the vehicle width, the axle number, the axle distance, the total axle length, the running speed and the gravity center position of the dynamic vehicle.

10. The dynamic vehicle weighing method of claim 6, wherein the relationship between the shift of the reflection center wavelength of the first stressed fiber grating axially attached to the surface of the first cantilever beam and the weight applied at the supporting point of the center of gravity is expressed as:

wherein λ is_BIs Λ and n_effFunction of n_effFor effective refraction of laser light propagating in optical fibreRatio, Λ, is the period of the Bragg grating_e＝n_eff ²[P₂-μ(P₁+P₂)][ 2 ] represents the effective elasto-optic coefficient of the FBG material, where P₁And P₂Is the elasto-optic coefficient of the FBG material; μ is the poisson's ratio of the FBG material; r is₀The radius of the end face of the transmission rod; the FBG material is a strain sheet material; h is the thickness of the membrane; e is the elastic modulus of the strain gauge; b₁、b₂L and d are the width of the upper bottom, the width of the lower bottom, the length and the thickness of the first cantilever beam respectively; c is a constant related to the ratio of the widths of the upper and lower bottoms of the first cantilever; z is the wheelbase; m is the weight acting at the center of gravity support point; g is the gravitational acceleration of the earth.

Technical Field

The invention belongs to the technical field of photoelectron measuring devices, and particularly relates to a dynamic weighing device and a dynamic weighing method for a fiber bragg grating vehicle, which are mainly applied to places with high safety requirements like urban roads, viaducts, high-speed intersections and the like.

Background

With the development of national economy, the rise and prosperity of logistics industry and the prosperity of passenger transportation industry, highway transportation occupies an important position in various transportation industries, and the public is concerned with property and life safety. Especially, the overload behaviors such as overweight and overtaking of the road seriously affect the service life of the road and the safety of vehicles and passengers. At present, the automobile load standard is an important basis for carrying out design and bearing capacity detection and evaluation of a highway bridge, and the automobile load condition on the actual highway bridge is greatly different from the current standard, so that various diseases of the bridge are caused quite frequently. Therefore, the work of supervising road overload has been the focus of the transportation industry. As for overload monitoring, static monitoring and dynamic monitoring are adopted, and static monitoring requires vehicle deceleration or even parking for weighing, so that static monitoring is not favorable for traffic smoothness and supervision means concealment, and dynamic monitoring is the most popular monitoring technology at present.

Dynamic weighing systems are capable of weighing a moving vehicle without the vehicle being measured stopping during the measurement. The dynamic weighing system plays an important role in road paving, bridge design and monitoring and traffic management. The dynamic weighing system can also improve the static weighing efficiency, reduce vehicles against regulations and provide accurate statistical data such as road flow for traffic managers.

For a piezoceramic dynamic weighing sensor, the inherent properties of the piezoelectric material, such as hysteresis effects, creep effects and temperature sensitivity, greatly limit its application. Due to these disadvantages, the zero drift of the sensor may occur randomly and cannot be completely removed. Therefore, this method cannot achieve high accuracy and requires frequent calibration. In the last two decades, with the development of optical information technology, the price of optical information products is gradually reduced, and the optical fiber sensing technology is also greatly developed. Compared with the traditional dynamic measurement technology based on the electrical quantity, the optical fiber sensor has the advantages of high sensitivity, electromagnetic interference resistance, corrosion resistance, light weight, low power consumption and the like.

Currently, fiber grating dynamic weighing systems such as fiber grating high-speed dynamic automobile dynamic weighing methods, fiber grating rack dynamic weighing sensors, portable fiber dynamic weighing systems, and fiber grating sensing technology-based dynamic weighing systems perform dynamic vehicle weight measurements by adhering a fiber grating string to a stress plate; such as an intensity demodulation type fiber chirped grating weighing sensor, performs dynamic vehicle weight measurement via a cantilever beam.

At present, a fiber bragg grating dynamic weighing system, such as an automobile dynamic weighing method (CN201410091018) based on fiber bragg grating high-speed dynamics, a rack dynamic weighing sensor (CN201721192342) based on fiber bragg grating, has a problem that measurement errors are caused by gravity center shift, that is, the measured dependent variable is different due to the deviation of the gravity point and the position of the measured fiber bragg grating, so that measurement errors are caused; for example, a portable optical fiber dynamic weighing system (CN201410654078), an intensity demodulation type optical fiber chirped grating weighing sensor (CN200910097187) and a dynamic weighing system (201620564898.X) based on an optical fiber grating sensing technology have the problems of poor sealing performance and the problem that a sensing structure and a sensing grating are easily corroded by a severe environment. More importantly, the existing fiber grating weighing sensors lack the function of replaceable maintenance, under the common conditions, a bending beam is large and heavy, a sensor probe must be embedded into gravel, concrete or soil or pavement (asphalt or concrete), if one part of a fiber grating string has a problem, the whole sensor can only be used as a waste, and a large amount of manpower and material resources are needed to replace and install the sensor; at present, the fiber bragg grating weighing sensors lack the function of vehicle identification and need to be assisted by other technical means (such as induction coils and infrared induction); all of these drawbacks will limit the application of dynamic weighing systems.

Disclosure of Invention

In order to solve the technical problem, the invention well realizes the sealing of the fiber grating dynamic vehicle weight sensor, and completely separates the internal sensing structure of the sensor from the outside. Meanwhile, the traditional stress plate is divided into independent small blocks according to the fiber bragg grating, and gravity center supporting points are added, so that the gravity center deviation problem of the traditional sensor is solved. In addition, the fiber grating weighing sensors are connected through the base, so that the fiber grating weighing sensors can be replaced, and the maintainability of a weighing system is greatly facilitated. The invention also adds a high-sensitivity fiber grating acceleration sensor, and realizes the recognition function of the whole vehicle.

The method can measure the wheel weight, axle weight, vehicle width, axle number, axle distance, total axle length, arrival time and running speed of the dynamic vehicle, and realize the type identification and the real-time weight monitoring of the dynamic vehicle.

In a first aspect, the present invention provides a fiber grating vehicle dynamic weighing sensor, comprising: the upper opening of the shell is connected with the strain gauge; the inner wall of the shell is provided with a plurality of cantilever beams, one ends of the cantilever beams are connected with the inner wall of the shell, the other ends of the cantilever beams are free ends, and the middle sections of the cantilever beams are connected with the fiber bragg grating; the center of the top surface of the strain gauge is provided with a bulge, the center of the bottom surface of the strain gauge is connected with one end of the transmission rod, and the other end of the transmission rod is contacted with the free end of each cantilever beam.

In a second aspect, the present invention further provides a fiber grating vehicle dynamic weighing apparatus, including: the dynamic weighing sensor comprises a base, wherein a plurality of dynamic weighing sensors according to the first aspect are mounted on the base, and the tops of the weighing sensors are connected with a weighing plate in a matching manner; the base comprises a plurality of sensor mounting holes, and a set distance is reserved between the two sensor mounting holes; and the center of the lower surface of the weighing plate is provided with a groove structure matched with the bulge of the stress sheet.

In a third aspect, the present invention provides a fiber grating vehicle dynamic weighing method, in which a dynamic weighing apparatus according to the above embodiment is used for weighing a vehicle, and the steps include:

measuring the drift amount of the reflection wavelength of each fiber grating in real time through a fiber grating demodulator, and calculating to obtain the weight value and the vibration data measured by each weighing sensor;

and carrying out whole vehicle analysis on the measured data, and obtaining the wheel weight, axle weight, whole vehicle weight, vehicle width, axle number, axle distance, total axle length, driving speed and gravity center position of the dynamic vehicle.

Compared with the prior art, the invention has the following beneficial effects:

1. according to the invention, through the structural arrangement of the shell, the strain gauge, the cantilever beam and the fiber bragg grating, the center of the top surface of the strain gauge is provided with the bulge to form a gravity supporting point, and on the premise of realizing better sealing and isolation of the sensor, the problem of gravity center offset of the optical fiber weighing sensing structure is solved.

2. According to the invention, through the structural arrangement of the shell, the strain gauge, the cantilever beam and the fiber bragg grating, the traditional stress plate is divided into independent strain gauges according to the fiber bragg grating to form independent small blocks, so that the dynamic weighing sensor is independent and replaceable, the replacement of a single weighing sensor can be carried out on a sensor group on the premise of not needing a large amount of manpower and material resources, and the later maintenance is facilitated.

3. The vibration sensing structure formed by the second cantilever beam, the heavy block and the second fiber bragg grating is additionally arranged in the weighing sensor and used for measuring the vibration acceleration, the whole vehicle identification of the dynamic vehicle is realized on the premise of ensuring the all-fiber sensing, and the number and the position of the vibration structure can be randomly adjusted according to the requirement.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of this application, illustrate embodiments of the application and, together with the description, serve to explain the application and are not intended to limit the application.

FIG. 1 is a top view of a base of the dynamic weighing apparatus of the present invention;

FIG. 2 is a cross-sectional view of a front view of a base of the dynamic weighing apparatus;

FIG. 3 is a top view of a load cell of the dynamic weighing apparatus;

FIG. 4 is a cross-sectional view of a first elevation view of a load cell of the dynamic weighing apparatus;

FIG. 5 is a schematic diagram of a cantilever beam structure sensing configuration of a load cell of the dynamic weighing apparatus;

FIG. 6 is a cross-sectional view of a front view of a second load cell of the dynamic weighing apparatus;

FIG. 7 is a cross-sectional view of a front view of the dynamic weighing apparatus;

FIG. 8 is a cross-sectional view of the dynamic weighing apparatus with the addition of a cover plate in a rear elevation view;

FIG. 9 is a top view of the dynamic weighing apparatus with the addition of a cover plate;

FIG. 10 is a schematic view of the installation of the dynamic weighing apparatus and method;

comprises a base 1; 2. a sensor mounting hole; 3. fixing the counter bore; 4. a sensor attachment hole; 5. an optical cable joint; 6. an optical cable; 7. a center of gravity support point; 8. a strain gauge; 9. a sensor housing; 10. a sensor fixing hole; 11. an optical fiber jumper; 12. a transmission rod; 13. a first cantilever beam; 14. a first stress fiber grating; 15. temperature compensation fiber grating; 16. an optical fiber; 17. a second cantilever beam; 18. a second stress fiber grating; 19. A weight block; 20. sealing gaskets; 21. a weighing plate; 22. fiber grating demodulator.

The specific implementation mode is as follows:

the invention is further described with reference to the following figures and examples.

It should be noted that the following detailed description is exemplary and is intended to provide further explanation of the disclosure. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs.

It is noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of example embodiments according to the present application. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, and it should be understood that when the terms "comprises" and/or "comprising" are used in this specification, they specify the presence of stated features, steps, operations, devices, components, and/or combinations thereof, unless the context clearly indicates otherwise.