Bridge bolt loosening convenient detection device combined with unmanned aerial vehicle and detection method

Abstract

The application relates to a bridge bolt loosening convenient detection device and detection method combined with a UAV, a loosening indication device is installed on a screw rod between a nut of a detected bolt and a steel truss bridge component; the loosening indication device comprises a first conductive sheet, a pressure ring and a second conductive sheet which are sequentially and gaplessly stacked in a direction from the nut to the connected steel truss bridge component; the first conductive sheet, the pressure ring, the second conductive sheet and a diode bulb form a current path; when the detected bolt is detected, the steel truss bridge component is knocked; if the detected bolt is loosened, the first conductive sheet and the second conductive sheet in the loosening indication device installed on the detected bolt collide with the pressure ring, the pressure ring generates a positive pressure electric effect and discharges, the current path is electrified, and the diode bulb emits light. The application can conveniently, efficiently, at low cost and with high accuracy detect bolt loosening in a steel truss bridge.

Description

TECHNICAL FIELD

[0001] The application relates to a bridge bolt loosening convenient detection device and method combined with a drone and belongs to the technical field of bridge safety detection. BACKGROUND

[0002] Steel structures are widely used in civil engineering structures due to their high strength, light weight, good plasticity, high reliability, high degree of installation mechanization, fast construction speed, various connection methods, green energy saving and other advantages. Steel structure bridges are the main form of long-span bridges. In the 1930s, the first self-designed and built steel bridge in China, Qiantang River Bridge, was opened to traffic, marking the beginning of the curtain of self-construction of steel structure bridges in China. At present, the construction of highway and railway steel structure bridges in China has reached the world leading level, and a large number of steel structure bridges with world influence have been built and put into use in various parts of China. Steel truss bridges have the advantages of large rigidity and convenient component transportation, and are widely used in long-span railway bridges, highway bridges and highway-railway combined bridges.

[0003] Steel truss bridges generally adopt welding or bolt connection to connect components. Compared with welding, bolt connection has the advantages of high bearing capacity, low cost, convenient construction and detachability, and is more widely used in steel truss bridges. However, under the coupling influence of wind-induced vibration, automobile vibration, train vibration, temperature action and other factors, bolts are prone to loosen and fail, and even fall off. On the one hand, bolt loosening failure will lead to a decrease in the bearing capacity of the node, threatening the safe use of the whole bridge; on the other hand, bolt falling off may hit high-speed trains or cars, causing serious traffic accidents. Therefore, accurate detection of bolt loosening is an important work to ensure the safety of steel truss bridge structure and traffic safety.

[0004] At present, the detection of bolt loosening mainly includes experience judgment method and sensor detection method. The experience judgment method relies on technical personnel to reach the scene and detect the bolts through visual inspection or torque wrench. The sensor detection method relies on sensors and detection equipment to detect the impedance, sound wave and other parameters of the bolts before and after loosening, and to distinguish the bolt loosening condition by comparison. Both methods need personnel or sensors to approach the bolts for individual detection. Since the number of bolts in large steel truss bridges is huge and most of them are located at high places that are difficult to reach, the detection signal is also easily disturbed by noise. Therefore, the practicability and reliability of the two methods are difficult to meet the convenient and reliable requirements of steel truss bridge bolt loosening detection, and a steel truss bridge bolt detection technology that does not need to reach the bolt position and has high efficiency, good reliability and low cost is urgently needed. SUMMARY

[0005] The application provides a bridge bolt loosening convenient detection device combined with a UAV and a detection method.

[0006] The application solves the technical problems by adopting the technical solutions:

[0007] A bridge bolt loosening convenient detection device combined with a UAV, the screw rod of each detected bolt is arranged on the connected steel truss bridge component, the detected bolt is fastened through a nut, and a loosening indication device is arranged on the screw rod between the nut and the steel truss bridge component.

[0008] The loosening indication device comprises a first conductive sheet, a pressure ring and a second conductive sheet which are sequentially and gaplessly arranged on the screw rod from the nut to the connected steel truss bridge component, the first conductive sheet is connected with the second conductive sheet through a first conductive wire and a second conductive wire, and the first conductive sheet, the pressure ring and the second conductive sheet form a current path with a diode bulb.

[0009] When the detected bolt is detected, the steel truss bridge component is knocked, if the detected bolt is loose, the first conductive sheet and the second conductive sheet of the loosening indication device arranged on the detected bolt collide with the pressure ring, the pressure ring generates a positive pressure electric effect and discharges, the current path is electrified, and the diode bulb emits light.

[0010] As a further preferred embodiment of the application, a gasket is arranged between the first conductive sheet and the nut.

[0011] As a further preferred embodiment of the application, the pressure ring is made of piezoelectric ceramic material.

[0012] As a further preferred embodiment of the application, the first conductive sheet and the second conductive sheet are made of the same material as the detected bolt.

[0013] As a further preferred embodiment of the application, the first conductive sheet, the second conductive sheet and the pressure ring are all circular ring structures, and the inner diameter and the outer diameter of the first conductive sheet, the second conductive sheet and the pressure ring are all the same.

[0014] The inner diameter of the first conductive sheet, the second conductive sheet and the pressure ring is greater than the nominal diameter of the detected bolt.

[0015] As a further preferred embodiment of the application, an insulating coating is wrapped on the surface of the overall structure of the loosening indication device.

[0016] The detection method using the bridge bolt loosening convenient detection device combined with a UAV comprises the following steps:

[0017] Step S1: knock the steel truss bridge member of the detected bolt connection to make the steel truss bridge member and the detected bolt vibrate;

[0018] Step S2: start the unmanned aerial vehicle to collect images of the area of the detected bolt;

[0019] Step S3: pre-process the collected images by using OpenCV software;

[0020] Step S4: identify the pre-processed images by using a fast region convolutional neural network to determine whether the diode bulb of the detected bolt loosening indicating device emits light;

[0021] Step S5: if the diode bulb is identified to emit light, it is determined that the detected bolt is loose, and if the diode bulb is identified not to emit light, it is determined that the detected bolt is not loose.

[0022] Through the above technical scheme, compared with the prior art, the present application has the following beneficial effects:

[0023] 1. The bridge bolt loosening convenient detection device combined with the unmanned aerial vehicle provided by the present application fully considers the fact that the number of bolts of a large steel truss bridge is large and most of them are installed in a high place that is difficult to reach, adopts a loosening indicating device based on the piezoelectric effect, has a simple structure, is low in cost, and has good long-term reliability;

[0024] 2. The bridge bolt loosening convenient detection device combined with the unmanned aerial vehicle provided by the present application uses the unmanned aerial vehicle to shoot images of whether the diode bulb of the loosening indicating device emits light to detect bolt loosening, without the need for detection personnel to reach the position of the detected bolt, and is simple and easy to operate and has strong practicality;

[0025] 3. The detection method of the bridge bolt loosening convenient detection device combined with the unmanned aerial vehicle provided by the present application uses a fast region convolutional neural network to one-time discriminate whether the loosening indicating device of all bolts in the image range emits light, realizes all detection of the loosening condition of the bolt group at one time, has good precision and high efficiency;

[0026] 4. The bridge bolt loosening convenient detection device combined with the unmanned aerial vehicle provided by the present application, the first conductive sheet and the second conductive sheet of the loosening indicating device are made of the same material as the detected bolt, and the loosening indicating device is installed between the nut of the original bolt structure and the steel truss bridge member, and does not affect the stress state of the steel truss bridge member and the bolt. BRIEF DESCRIPTION OF DRAWINGS

[0027] The present application will be further described below in combination with the drawings and examples.

[0028] Figure 1 is the overall structure schematic diagram of the loosening indicating device in the preferred embodiment provided by the present application;

[0029] Figure 2 is a schematic diagram of the current path of the loosening indication device in the preferred embodiment provided by the present application;

[0030] Figure 3 is a schematic diagram of the pressure ring structure of the loosening indication device in the preferred embodiment provided by the present application;

[0031] Figure 4 is a schematic diagram of the structure of the first conductive sheet and the second conductive sheet of the loosening indication device in the preferred embodiment provided by the present application;

[0032] Figure 5 is a schematic diagram of the installation of the loosening indication device in the preferred embodiment provided by the present application on the bolt to be detected;

[0033] Figure 6 is a front view of the loosening indication device in the preferred embodiment provided by the present application;

[0034] Figure 7 is Figure 1 A-A sectional view of the loosening indication device in the preferred embodiment provided by the present application;

[0035] Figure 8 is Figure 7 B-B sectional view of the loosening indication device in the preferred embodiment provided by the present application;

[0036] Figure 9 is Figure 7 C-C sectional view of the loosening indication device in the preferred embodiment provided by the present application.

[0037] In the figure: 1 is a pressure ring, 2 is a first conductive sheet, 3 is a second conductive sheet, 4 is a first conductive wire, 5 is a second conductive wire, 6 is a diode bulb, 7 is a gasket, 8 is a nut, 9 is a screw rod, 10 is a steel truss bridge member, and 11 is an insulating coating. Embodiment

[0038] The present application will now be further described in detail with reference to the accompanying drawings. In the description of the present application, it should be understood that the terms "left side", "right side", "upper part", "lower part", and the like indicate the orientation or positional relationship shown in the drawings, and are only used for the purpose of facilitating the description of the present application and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and "first", "second", and the like do not represent the importance of the parts, and therefore cannot be understood as limiting the present application. The specific dimensions used in the present embodiment are only used to illustrate the technical solutions and do not limit the protection scope of the present application.

[0039] As set forth in the background, the number of bolts of large steel truss bridge is very large, which can reach tens of thousands, and most of the bolts are set at high places, so the detection personnel cannot easily reach. In the current technology, there is also a design that the bolt and the related detection component form a current path, when the bolt is loose, the current path cannot form current to cause the warning light to go out, however, such design has two disadvantages for the large bolt group, first, it is difficult to provide power for thousands of bolts, second, it is difficult to identify the off state of the bolt loosening.

[0040] Figure 1 The core structure in the detection device provided by the application is a loosening indication device, which uses a superior intelligent material, piezoelectric ceramic material, as a pressure ring 1. Under the action of continuously changing mechanical pressure (when the bolt is in a loosening state), the positive and negative charge centers in the pressure ring appear relative displacement and polarization, resulting in the appearance of bound charges with opposite signs on the surfaces at both ends of the material, generating a positive piezoelectric effect, i.e. discharge. At this time, the current path in the loosening indication device is connected, the warning light emits light, and the loosening of the bolt at this position is displayed.

[0041] The loosening indication device is installed on the steel truss bridge member 10, and the overall structure is as shown in Figures 5-6 Each bolt to be detected is provided with a screw rod 9 arranged on the connected steel truss bridge member, and the bolt to be detected is fastened by a nut 8. The loosening indication device is installed on the screw rod between the nut and the steel truss bridge member. The application attempts to use the structure of the bolt to be detected and the steel truss bridge member itself, and slightly modify the detection part to realize the detection of bolt loosening.

[0042] Hereinafter, the specific structure of the loosening indication device will be further described. The loosening indication device includes a first conductive sheet 2, a pressure ring, and a second conductive sheet 3, which are sequentially and gaplessly stacked from the nut to the connected steel truss bridge member. A gasket 7 is arranged between the first conductive sheet and the nut. The first conductive sheet is connected to the second conductive sheet through a first conductive wire 4 and a second conductive wire 5, respectively, and the first conductive sheet, the pressure ring, the second conductive sheet, and the diode bulb form a current path as shown in Figure 2 When the bolt to be detected is detected, the steel truss bridge member is knocked, and if the bolt to be detected is loose, the first conductive sheet, the second conductive sheet, and the pressure ring of the loosening indication device installed on the bolt to be detected collide, the pressure ring generates a positive piezoelectric effect and discharges, the current path is electrified, and the diode bulb emits light.

[0043] The bolt looseness is indicated by the light emitted by the diode bulb, which utilizes the piezoelectric effect. If the detected bolt is tightened, the gasket, the looseness indicating device and the steel truss bridge member are in close contact, so even if the steel truss bridge member vibrates, the gasket, the looseness indicating device and the steel truss bridge member move synchronously without colliding with each other, and the pressure ring is subjected to a constant pressure, so the piezoelectric effect (the pressure ring generates an electric charge) does not occur in the pressure ring, and the entire current path is not connected to be powered on, so the diode bulb is always in an off state. When the detected bolt is loose, the gasket, the looseness indicating device and the steel truss bridge member cannot move synchronously, and mutual collision occurs, i.e. the first conductive sheet, the second conductive sheet and the pressure ring collide with each other multiple times, the pressure ring is subjected to a changing pressure, so the piezoelectric effect (the pressure ring generates an electric charge) occurs in the pressure ring, and the current flows to the diode bulb through the first conductive sheet, the second conductive sheet, the first conductive wire and the second conductive wire, causing the diode bulb to emit light.

[0044] In the above description, it is obvious that the pressure ring is the core of the core, so to realize the piezoelectric effect, the pressure ring needs to be made of piezoelectric ceramic material, which is a superior intelligent material. At the same time, in order not to affect the stress state of the steel truss bridge member and the bolt, the first conductive sheet and the second conductive sheet are made of the same material as the detected bolt. Figure 3 and Figure 4 As shown in the drawings, the first conductive sheet, the second conductive sheet and the pressure ring are all circular ring structures, and the inner diameter and the outer diameter of the first conductive sheet, the second conductive sheet and the pressure ring are all the same. The inner diameter of the first conductive sheet, the second conductive sheet and the pressure ring is slightly larger than the nominal diameter of the detected bolt.

[0045] Figures 7-9 As shown in the drawings, an insulating coating 11 is wrapped on the overall structure surface of the looseness indicating device, which is to ensure that the electric charge generated by the pressure ring does not flow to the gasket, the screw rod, the nut and the steel truss bridge member of the detected bolt.

[0046] In this application, in addition to designing the looseness indicating device, the characteristics of the structure itself are maximally utilized to detect the looseness of the detected bolt. In view of the actual installation status of the large steel truss bridge bolt, it is also a major project to check whether the diode bulb emits light or not. Therefore, this application adopts a drone, which can complete long-distance image shooting through a wireless radio control device and a self-provided program control device. After collecting relevant images, artificial intelligence algorithms can be used to identify various information in the images with high precision and high efficiency.

[0047] Therefore, the application also provides a detection method for the bridge bolt looseness convenient detection device combined with a drone, which specifically includes the following steps:

[0048] Step S1: knock the steel truss bridge member of the detected bolt connection to make the steel truss bridge member and the detected bolt vibrate;

[0049] Step S2: start the unmanned aerial vehicle to collect images of the area of the detected bolt;

[0050] Step S3: use OpenCV software to pre-process the collected images;

[0051] Step S4: use the fast region convolutional neural network to identify the pre-processed images to determine whether the diode bulb of the detected bolt loosening indicating device emits light;

[0052] Step S5: if the diode bulb is identified to emit light, it is determined that the detected bolt is loose, and if the diode bulb is identified not to emit light, it is determined that the detected bolt is not loose.

[0053] The piezoelectric ceramic material, unmanned aerial vehicle technology and image recognition technology are combined in the application, which is a feasible way to realize the bolt loosening detection of the steel truss bridge. Meanwhile, the bolt loosening detection of the steel truss bridge is realized conveniently, efficiently, at low cost and accurately.

[0054] Those skilled in the art can understand that, unless otherwise defined, all terms (including 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 should also be understood that terms such as those defined in a general dictionary should be understood to have meanings consistent with those in the context of the prior art, and should not be interpreted in an idealized or overly formal sense unless otherwise defined.

[0055] The meaning of "and / or" described in the application includes both individual existence and simultaneous existence.

[0056] The meaning of "connection" described in the application can be direct connection between components or indirect connection between components through other components.

[0057] Based on the above ideal embodiments according to the application, the above description, relevant personnel can make various changes and modifications without deviating from the technical idea of the application. The technical scope of the application is not limited to the contents of the specification, and the technical scope must be determined according to the scope of the claims.

Claims

1. A convenient bridge bolt loosening detection device combined with a drone, wherein the thread (9) of each bolt to be detected passes through the connected steel truss bridge component (10), and the bolt to be detected is tightened by a nut (8), characterized in that: A loosening indication device is installed on the screw rod (9) between the nut (8) and the steel truss bridge member (10); The loosening indication device comprises a first conductive sheet (2), a pressure ring (1) and a second conductive sheet (3) sleeved on the screw rod (9), and the first conductive sheet (2), the pressure ring (1) and the second conductive sheet (3) are sequentially and gaplessly stacked from the nut (8) to the connected steel truss bridge member (10); the first conductive sheet (2) is connected to the second conductive sheet (3) through the first conductive wire (4) and the second conductive wire (5) through the second conductive wire (5) at the same time. Diode bulb (6), that is, the first conductive sheet (2), the pressure ring (1), the second conductive sheet (3) and the diode bulb (6) form a current path; The pressure ring (1) is made of piezoelectric ceramic material; the first conductive sheet (2) and the second conductive sheet (3) are made of the same material as the detected bolt; the first conductive sheet (2), the second conductive sheet (3) and the pressure ring (1) are all circular ring structures, and the inner diameter and the outer diameter of the first conductive sheet (2), the second conductive sheet (3) and the pressure ring (1) are the same; the inner diameter of the first conductive sheet (2), the second conductive sheet (3) and the pressure ring (1) is slightly larger than the nominal diameter of the detected bolt; When the detected bolt is detected, knock the steel truss bridge member (10), if the detected bolt is loose, under the action of the constantly changing mechanical pressure, the positive and negative charge centers in the pressure ring appear relative displacement and polarization, the first conductive sheet (2), the second conductive sheet (3) and the pressure ring (1) in the loosening indication device installed on the detected bolt collide, the pressure ring (1) generates positive piezoelectric effect and discharges, the current path is electrified, and the diode bulb (6) emits light; The image of whether the diode bulb in the loosening indication device emits light is photographed by the unmanned aerial vehicle, and whether the loosening indication device of all bolts in the image range emits light is determined at one time by using the fast regional convolutional neural network.

2. The bridge bolt loosening convenient detection device combined with the unmanned aerial vehicle according to claim 1, characterized in that: A gasket (7) is arranged between the first conductive sheet (2) and the nut (8).

3. The bridge bolt loosening convenient detection device combined with the unmanned aerial vehicle according to claim 1, characterized in that: An insulating coating (11) is wrapped on the surface of the overall structure of the loosening indication device.

4. The method for detecting the loosening of the bridge bolt by using the device for detecting the loosening of the bridge bolt of the unmanned aerial vehicle according to claim 3, characterized in that: Specifically comprising the following steps: Step S1: knock the steel truss bridge member (10) connected with the detected bolt to make the steel truss bridge member (10) and the detected bolt vibrate; Step S2: start the unmanned aerial vehicle to collect images of the region of the detected bolt; Step S3: use OpenCV software to preprocess the collected images; Step S4: use the fast regional convolutional neural network to identify the preprocessed images to determine whether the diode bulb (6) of the loosening indication device of the detected bolt emits light; Step S5: if the diode bulb (6) is identified to emit light, it is determined that the detected bolt is loose, and if the diode bulb (6) is identified not to emit light, it is determined that the detected bolt is not loose.

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