In-plane dynamic displacement measurement device for stay cable based on machine vision

Abstract

The utility model discloses a kind of in-plane dynamic displacement measuring devices of cable-stayed cable method based on machine vision, comprising: cable clamp, it is installed on cable-stayed cable;Rigid measuring plate, its upper surface has measurement target mark, and the plane of the rigid measuring plate is perpendicular to the axis of the cable clamp;Lower diagonal bracing, fixed on bridge deck, and its axis is parallel to the plane of the rigid measuring plate;Video equipment, fixedly connected in the upper end portion of the lower diagonal bracing, the measurement target mark on the upper surface of the rigid measuring plate is located in the visual field position of the video equipment.The utility model device is high in economy, strong in applicability and high in displacement measurement precision.

Description

Technical Field

[0001] This utility model relates to the field of equipment technology for long-span bridges. More specifically, this utility model relates to a machine vision-based in-plane dynamic displacement measurement device for cable-stayed bridges. Background Technology

[0002] As a long-span bridge structure, the stay cables of a cable-stayed bridge are key components that bear loads and transmit forces. Under external excitations such as wind loads and traffic loads, stay cables are prone to lateral vibrations, and their vibration displacement in the normal plane directly reflects the stress state and vibration characteristics. Currently, external dampers are not ideal in suppressing out-of-plane vibrations of stay cables, mainly because of inaccurate understanding of the direction, magnitude, and time-domain characteristics of the vibration displacement. Therefore, accurately obtaining the displacement values ​​and their variation patterns in the normal plane of stay cables has significant theoretical guidance and engineering value for the design of external vibration control devices (especially out-of-plane vibration control devices).

[0003] However, existing technologies for measuring and analyzing in-plane displacements using the cable-stayed bridge method still have the following shortcomings:

[0004] (1) Limitations of wire sensors: Wire sensors can only measure vibration displacement in a fixed direction, while the direction of vibration displacement of cable stays is directly related to the form of external loads (such as wind, traffic loads, etc.) and may exist in any direction in the normal plane. In addition, wire sensors are easily damaged in complex environments and have low reliability.

[0005] (2) Shortcomings of satellite systems: There is a significant angle between the vibration direction in the cable plane and the vertical direction. Measurement methods based on satellite systems (such as Beidou and GPS) require conversion devices, have insufficient vertical accuracy, and are expensive, which is not conducive to large-scale promotion and use.

[0006] (3) Deficiencies of image processing technology: Extracting displacement information by taking images of cable vibration and combining them with edge line image processing algorithms requires a wide field of view and fixed video equipment, resulting in poor environmental adaptability. Furthermore, the image processing technology is complex and has low accuracy.

[0007] (4) Accelerometer error problem: When an accelerometer is installed on the cable-stayed bridge and the displacement is obtained by integration, the selection of boundary conditions can easily introduce large errors, affecting the accuracy of the measurement results.

[0008] The aforementioned shortcomings limit in-depth research on the vibration characteristics of cable stays and also restrict the effectiveness of existing damping devices. Utility Model Content

[0009] The purpose of this invention is to provide a machine vision-based in-plane dynamic displacement measurement device for cable-stayed bridges, which is highly economical, widely applicable, and provides high displacement measurement accuracy. The obtained data will be directly applied to the study of cable-stayed bridge vibration characteristics and the design optimization of external vibration damping devices, significantly improving vibration reduction effects and effectively suppressing harmful vibrations.

[0010] The technical solution adopted by this utility model to solve this technical problem is: a machine vision-based in-plane dynamic displacement measurement device for cable-stayed bridges, comprising:

[0011] Cable clamps are installed on stay cables;

[0012] A rigid measuring plate with measuring target markings on its upper surface, and the plane of the rigid measuring plate is perpendicular to the axis of the cable clamp;

[0013] The lower diagonal brace is fixed to the bridge deck, and its axis is parallel to the plane of the rigid measuring plate;

[0014] The video device is fixedly connected to the upper end of the lower inclined strut, and the measurement target mark on the upper surface of the rigid measuring plate is located in the field of view of the video device.

[0015] As a further embodiment of this utility model, it also includes a solar panel and its matching battery. The solar panel is fixedly installed on the upper surface of the lower inclined support rod, and the matching battery is fixedly installed on the lower surface of the lower inclined support rod for supplying power to the video equipment.

[0016] As a further embodiment of this utility model, the measuring target mark on the upper surface of the rigid measuring plate is placed in the center of the video device's field of view.

[0017] As a further aspect of this invention, the video device is an edge computing device with built-in hardware and software capable of real-time processing of target images.

[0018] As a further embodiment of this utility model, the video device is connected to a wireless router via a network cable, and the wireless router is used to remotely transmit and upload the image data processed by the video device to a cloud acquisition system for storage, analysis and display.

[0019] As a further embodiment of this utility model, the rigid measuring plate is fixed to the cable clamp by welding or bolting.

[0020] This utility model has at least the following beneficial effects:

[0021] 1. High measurement accuracy: By using video equipment to capture the motion trajectory of the target mark on the rigid measuring plate at close range in high definition, the vibration law of the cable under load can be directly reflected. It can accurately obtain the direction, magnitude and variation law of vibration displacement, and can also conveniently obtain parameters such as cable vibration frequency, overcoming the problem of low accuracy of existing measurement methods.

[0022] 2. Economical and practical: Compared with the high cost of satellite system measurement methods and equipment, this patent uses common video equipment, cable clamps, diagonal braces and other conventional components, which is less expensive and conducive to large-scale promotion and use.

[0023] 3. Facilitating the design optimization of external dampers: The obtained cable vibration displacement data can be directly applied to the design optimization of external vibration reduction devices, significantly improving the vibration reduction effect and effectively suppressing harmful vibrations.

[0024] 4. Wide range of applications: This patent is not only applicable to cable stays, but also to vibration control of flexible suspenders and rigid suspenders in bridge engineering and other fields, thus expanding its application scope.

[0025] 5. Strong environmental adaptability: Utilizing solar panel power reduces reliance on external power sources, making it suitable for complex environments such as the field. Furthermore, the device has a simple structure, is not dependent on specific environmental conditions, and avoids the problems of existing image processing technologies requiring a wide field of view and fixed video equipment, resulting in poor environmental adaptability.

[0026] Other advantages, objectives and features of this invention will be partly apparent from the following description, and partly understood by those skilled in the art through study and practice of this invention. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the in-plane dynamic displacement measurement device based on machine vision using the cable-stayed bridge method of this utility model.

[0028] Among them, 1-top surface of main beam, 2-stayed cable, 3-cable clamp, 4-measuring target mark, 5-rigid measuring plate, 6-video equipment, 7-bracket, 8-solar panel and its matching battery, 9-wireless router, 10-lower diagonal brace, 11-diagonal brace leg. Detailed Implementation

[0029] The present invention will now be described in detail and completely with reference to the accompanying drawings. Those skilled in the art will be able to implement the present invention based on these descriptions. Before describing the present invention with reference to the accompanying drawings, it should be particularly noted that the technical solutions and features provided in the various parts of the present invention, including the following description, can be combined with each other without conflict.

[0030] Furthermore, the embodiments of the present invention described below are generally only a part of the embodiments of the present invention, and not all of the embodiments. Therefore, all other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort should fall within the protection scope of the present invention.

[0031] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments. The specific implementation process is as follows:

[0032] like Figure 1 As shown, this utility model provides a machine vision-based device for measuring the dynamic displacement of a cable-stayed bridge in a two-plane configuration, comprising:

[0033] Cable clamp 3, installed on the stay cable 2, can be made of stainless steel, a common material on the market. This material is sturdy and durable, meeting the usage requirements. Cable clamp 3 is installed on the stay cable 2 using bolts for secure fastening, ensuring a stable connection. Common stay cables 2 have a diameter of 50-200 mm, corresponding to a cable clamp 3 inner diameter of 55-205 mm.

[0034] The rigid measuring plate 5 fits tightly with the cable clamp 3, and its upper surface has measurement target markings 4. The measuring plate can be made of aluminum alloy, which is lightweight and has high strength. Its plane is perpendicular to the axis of the cable clamp 3, and it can be fixed to the cable clamp 3 by welding or bolting during installation. The thickness of the rigid measuring plate 5 can be selected from 5 to 10 mm to ensure sufficient rigidity during measurement.

[0035] The lower diagonal brace 10 is fixed to the top surface 1 of the main beam and serves as the support structure for the device. A diagonal brace leg 11 can be installed on one side to improve the stability of the lower diagonal brace 10. The lower diagonal brace 10 can be made of carbon steel, whose strength meets the support requirements. Its axis is parallel to the plane of the rigid measuring plate 5. During installation, it can be installed by pre-embedding connectors on the bridge deck and then fixing the lower diagonal brace 10 to the connectors. The length of the lower diagonal brace 10 can be determined based on the distance from the bridge deck to the stay cable 2.

[0036] Video device 6, fixedly connected to the upper end of the lower inclined support rod 10 via bracket 7, is used to capture images of the measurement target mark 4. A commercially available high-definition industrial camera can be selected as video device 6, offering high image clarity. The measurement target mark 4 on the upper surface of the rigid measuring plate 5 is located within the field of view of video device 6. To ensure measurement accuracy, the measurement target mark 4 can be positioned in the center of the field of view of video device 6. Similar devices are commonly installed in industrial monitoring fields, such as visual inspection equipment on production lines. The frame rate of video device 6 can be set to 30~60 frames per second to meet measurement requirements.

[0037] Based on the aforementioned measuring device, the solar panel and its matching battery 8 power the video equipment 6. The solar panel can be a monocrystalline silicon solar panel, which has high conversion efficiency. The solar panel is fixedly installed on the upper surface of the lower inclined support 10, and the installation method can be a bracket fixation, ensuring that the solar panel can fully receive sunlight. The matching battery can be a lead-acid battery, which is low in cost and has stable performance, and is fixedly installed on the lower surface of the lower inclined support 10.

[0038] This technical solution may also include the following technical details to better achieve the technical effect: the measurement target mark 4 on the upper surface of the rigid measuring plate 5 is positioned in the center of the field of view of the video device 6. The measurement target mark 4 can be made of high-contrast reflective stickers to ensure clear identification when the video device 6 is recording. To ensure that the measurement target mark 4 is always in the center of the field of view of the video device 6, the positional relationship between the video device 6 and the rigid measuring plate 5 needs to be precisely adjusted during installation. The lower diagonal support rod 10 and the rigid measuring plate 5 can be fixed first, and then the installation angle and position of the video device 6 can be adjusted to make the measurement target mark 4 located in the center of the field of view.

[0039] This technical solution may also include the following technical details to better achieve the technical effect: the video device 6 is an edge computing device with built-in hardware and software that can process target images in real time.

[0040] This technical solution may also include the following technical details to better achieve the technical effect: the video device 6 is connected to the wireless router 9 via a network cable, and the wireless router 9 is used to remotely transmit and upload the image data processed by the video device 6 to the cloud acquisition system for storage, analysis and display.

[0041] This technical solution may also include the following technical details to better achieve the technical effect: the rigid measuring plate 5 is fixed to the cable clamp 3 by welding or bolt connection.

[0042] The measurement method of the in-plane dynamic displacement measurement device of cable-stayed bridge 2 based on machine vision: When cable-stayed bridge 2 vibrates, the rigid measuring plate 5 perpendicular to its axis moves accordingly. The video device 6 directly records the movement trajectory of the measuring target on the upper surface of the rigid measuring plate 5 at close range and in high definition. This movement trajectory directly reflects the vibration law of cable-stayed bridge 2 under load, such as the direction, magnitude and change law of vibration displacement. Furthermore, parameters such as the vibration frequency of the cable can be easily obtained.

[0043] Although the embodiments of this utility model have been disclosed above, they are not limited to the applications listed in the specification and embodiments. They can be applied to various fields suitable for this utility model. For those skilled in the art, other modifications can be easily made. Therefore, without departing from the general concept defined by the claims and their equivalents, this utility model is not limited to the specific details and embodiments shown and described herein.

Claims

1. A machine vision-based in-plane dynamic displacement measurement device using a cable-stayed bridge method, characterized in that, include: Cable clamps are installed on stay cables; A rigid measuring plate with measuring target markings on its upper surface, and the plane of the rigid measuring plate is perpendicular to the axis of the cable clamp; The lower diagonal brace is fixed to the bridge deck, and its axis is parallel to the plane of the rigid measuring plate; The video device is fixedly connected to the upper end of the lower inclined strut, and the measurement target mark on the upper surface of the rigid measuring plate is located in the field of view of the video device.

2. The in-plane dynamic displacement measurement device based on machine vision for cable-stayed bridges as described in claim 1, characterized in that, It also includes a solar panel and its matching battery. The solar panel is fixedly installed on the upper surface of the lower inclined support rod, and the matching battery is fixedly installed on the lower surface of the lower inclined support rod, for powering the video equipment.

3. The in-plane dynamic displacement measurement device based on machine vision for cable-stayed bridges as described in claim 1, characterized in that, The measurement target mark on the upper surface of the rigid measuring plate is placed in the center of the video device's field of view.

4. The in-plane dynamic displacement measurement device based on machine vision for cable-stayed bridges as described in claim 1, characterized in that, The video device is an edge computing device with built-in hardware and software capable of real-time processing of target images.

5. The in-plane dynamic displacement measurement device based on machine vision for cable-stayed bridges as described in claim 4, characterized in that, The video device is connected to a wireless router via a network cable. The wireless router is used to remotely transmit and upload the image data processed by the video device to the cloud acquisition system.

6. The in-plane dynamic displacement measurement device based on machine vision for cable-stayed bridges as described in claim 1, characterized in that, The rigid measuring plate is fixed to the cable clamp by welding or bolting.

Images