A spatial cable suspension bridge empty cable linear monitoring system

Abstract

The present invention provides a space cable suspension bridge empty cable linear monitoring system, including: a plurality of data acquisition devices, used to collect target data in the space cable suspension bridge empty cable state; a first empty cable state determination device, used to determine the first empty cable state according to the target data collected by the plurality of data acquisition devices; a second empty cable state simulation device, used to simulate and determine the second empty cable state of the space cable suspension bridge that meets the construction standards; a key point monitoring device, used to monitor the key points of the first empty cable state with reference to the second empty cable state, and output the key point adjustment strategy. This system takes into account the difference in changes of the space cable suspension bridge at different stages, and by simulating the second empty cable state, comparing the first empty cable state with the second empty cable state, determining the key points, and outputting the adjustment strategy, the accuracy and safety of the construction are improved, the construction control process is optimized, and the overall performance and construction quality of the bridge are finally improved.

Description

Technical Field

[0001] The invention belongs to the field of bridge monitoring, and in particular relates to an empty cable linear monitoring system for a space cable surface suspension bridge. Background Art

[0002] Spatial cable-surface suspension bridges are gaining more and more attention in the construction of long-span bridges due to their unique structure and aesthetic design. However, for complex spatial cable-surface structures, there are significant differences between the empty cable state and the completed bridge state in many aspects, and their construction difficulty is higher than that of general bridges. Therefore, an accurate and efficient monitoring system is needed to effectively detect them.

[0003] In the related technology, one method is to use machine vision to inspect the construction site. This method can only monitor construction risks such as cracks on the bridge surface, and cannot deeply monitor the overall construction status and potential risks of the bridge. Another method is to use various sensors to form an intelligent monitoring system. The sensors obtain the current bridge data and compare the current bridge data with the data of the corresponding part of the designed bridge to complete the monitoring. This method is not suitable for monitoring the space cable suspension bridge where there is a large difference between the empty cable state and the completed bridge state. Summary of the invention

[0004] In view of this, an object of the present invention is to provide a system and device for monitoring the line shape of empty cables of a space cable-surface suspension bridge, so as to meet the demand for construction monitoring of the space cable-surface suspension bridge.

[0005] In order to achieve the above object, the present invention provides the following technical solutions:

[0006] The present invention provides a system for monitoring the linear shape of an empty cable of a space cable surface suspension bridge, comprising: a plurality of data acquisition devices for collecting target data when the space cable surface suspension bridge is in an empty cable state; a first empty cable state determining device for determining a first empty cable state according to the target data collected by the plurality of data acquisition devices; a second empty cable state simulation device for simulating and determining a second empty cable state of the space cable surface suspension bridge that meets construction standards; and a key point monitoring device for monitoring each key point of the first empty cable state with reference to the second empty cable state, and outputting a key point adjustment strategy.

[0007] Optionally, multiple data acquisition devices include: a radar scanning device carried by a drone, used to obtain point cloud data of a space cable surface suspension bridge in an empty cable state; the first empty cable state includes the main cable linear shape, and the first empty cable state is determined according to the target data collected by multiple data acquisition devices, including: reconstructing a model of the point cloud data to obtain an empty cable state model of the space cable surface suspension bridge; determining the spatial area of ​​the main cable in the design model of the space cable surface suspension bridge according to the design model of the space cable surface suspension bridge; determining the spatial area of ​​the main cable in the empty cable state model of the space cable surface suspension bridge according to the scaling ratio of the empty cable state model of the space cable surface suspension bridge and the design model of the space cable surface suspension bridge; extracting point cloud data of the main cable in the spatial area of ​​the empty cable state model of the space cable surface suspension bridge as a target point cloud set; determining a target line in the target point cloud set, and performing curve smoothing on the target line to obtain the main cable linear shape.

[0008] Optionally, a distributed temperature sensor is used to obtain the temperature of each span of the suspension bridge; the first empty cable state also includes the transverse bridge coordinates of a preset suspension point in the empty cable state or the transverse inclination angle of the line connecting the upper and lower suspension points of the suspension cable in the empty cable state, and the first empty cable state is determined according to target data collected by multiple data acquisition devices, including: for the transverse bridge coordinates of the preset suspension cable in the empty cable state, according to the temperature of the corresponding span and the influence of the temperature on the length of the main cable, adjusting the original coordinates of the preset suspension cable on the main cable to obtain the target coordinates of the suspension cable, and obtaining the target coordinates of the suspension cable in the empty cable state model of the space cable surface suspension bridge. Mark the marked coordinates to determine the transverse coordinates of the marked points in the empty cable state model of the spatial cable-surface suspension bridge; or, for the lateral inclination angle of the line connecting the upper and lower suspension points of the cable in the empty cable state, adjust the original coordinates of the preset cable on the main cable according to the temperature of the corresponding span and the influence of the temperature on the length of the main cable to obtain the target coordinates of the cable, connect the target coordinates of the cable with the coordinates of the lower anchor point of the original cable in the empty cable state model of the spatial cable-surface suspension bridge to obtain a connecting line, and determine the angle between the connecting line and the horizontal plane as the lateral inclination angle of the line connecting the upper and lower suspension points of the cable in the empty cable state.

[0009] Optionally, the second empty cable state simulation device performs the following steps, including: constructing a spatial cable surface suspension bridge model according to the design drawings of the spatial cable surface suspension bridge using the MIDAS Civil tool; inputting a target temperature control instruction in each span of the spatial cable surface suspension bridge model, and adjusting the length of the main cable in each span of the spatial cable surface suspension bridge model according to the relationship between the temperature and the main cable length, wherein the temperature controlled by the target temperature control instruction is the corresponding temperature obtained by the distributed temperature sensor; using the segmented catenary analysis theory to analyze the adjusted suspension bridge model, and determine the stress-free length of the main cable, the coordinates of the hanging point and the state of the sling, the pre-bias and elevation of the saddle for installing the empty cable; and determining the empty cable line shape of the spatial cable surface suspension bridge at the target temperature according to the stress-free length of the main cable, the coordinates of the hanging point and the state of the sling, the pre-bias and elevation of the saddle for installing the empty cable.

[0010] Optionally, the second empty cable state simulation device performs the following steps, including: marking the target coordinates of the cables in the completed model of the spatial cable surface suspension bridge, and determining the transverse coordinates of the marked points in the completed model of the spatial cable surface suspension bridge; or, connecting the target coordinates of the cables and the coordinates of the lower anchor points of the original cables in the completed model of the spatial cable surface suspension bridge to obtain a connecting line, and determining the angle between the connecting line and the horizontal plane as the lateral inclination angle of the line connecting the upper and lower suspension points of the cables in the completed model of the spatial cable surface suspension bridge.

[0011] Optionally, a target line is determined in the target point cloud set, and a curve smoothing process is performed on the target line to obtain the main cable line shape, including: extracting a target point cloud subset with linear characteristics in the target point cloud set; determining the distribution direction vector of the target point cloud data in the target point cloud subset according to the principal component analysis method; judging whether the distribution direction vector of the target point cloud data satisfies the linear constraint condition, and if so, clustering the target point cloud data according to the clustering algorithm to obtain the main cable line shape, wherein the linear constraint condition is that there are multiple direction vectors whose dot products with the horizontal vector gradually increase and there are multiple direction vectors whose dot products with the horizontal vector gradually decrease.

[0012] Optionally, each key point of the first empty cable state is monitored with reference to the second empty cable state, and a key point adjustment strategy is output, including: calculating the difference between the parameters of each key point in the second empty cable state and the parameters in the first empty cable state to obtain the difference value of each key point; inputting the key point into the knowledge graph, searching for the influencing factors related to the key point; adjusting the parameters of each influencing factor of the spatial cable surface suspension bridge model in the first empty cable state according to the finite element analysis method, until the key point difference value corresponding to each influencing factor is less than a preset threshold; outputting the adjusted influencing factors and the parameters of the influencing factors as the key point adjustment strategy.

[0013] An embodiment of the present invention provides a system for monitoring the linear shape of empty cables of a space cable surface suspension bridge. Compared with comparing a first empty cable state with a completed bridge model, this embodiment takes into account the difference in changes of the space cable surface suspension bridge at different stages, and adopts a second empty cable state simulation device to simulate and determine the second empty cable state of the space cable surface suspension bridge that meets the construction standards. By simulating the empty cable state and comparing the first empty cable state with the second empty cable state, key points are determined, and adjustment strategies are output, thereby improving the accuracy and safety of construction, optimizing the construction control process, and ultimately improving the overall performance and construction quality of the bridge.

[0014] Other advantages, objectives and features of the present invention will be described in the following description and will be apparent to those skilled in the art to some extent, or those skilled in the art may be taught from the practice of the present invention. The objectives and other advantages of the present invention may be realized and obtained through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to make the purpose, technical solution and beneficial effects of the present invention clearer, the present invention provides the following drawings for illustration:

[0016] Figure 1 It is a schematic diagram of the structure of a space cable plane suspension bridge empty cable linear monitoring system in the present invention;

[0017] Figure 2 It is a schematic elevation projection diagram of a space cable-surface suspension bridge in the present invention;

[0018] Figure 3 It is a schematic diagram of plane projection of the space cable-surface suspension bridge in the present invention;

[0019] Figure 4 It is a schematic diagram of the empty cable state of the space cable plane suspension bridge in the present invention. DETAILED DESCRIPTION

[0020] The technical solution of the present invention will be described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0021] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, it can also be the internal connection of two components, it can be a wireless connection, or it can be a wired connection. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0022] In addition, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0023] This embodiment provides a space cable suspension bridge empty cable linear monitoring system, such as Figure 1 As shown, including:

[0024] A plurality of data acquisition devices 101 are used to acquire target data when the space cable-surface suspension bridge is in an empty cable state;

[0025] A first empty cable state determining device 102, configured to determine a first empty cable state based on target data collected by a plurality of data collection devices;

[0026] The second empty cable state simulation device 103 is used to simulate and determine the second empty cable state of the space cable surface suspension bridge that meets the construction standards;

[0027] The key point monitoring device 104 is used to monitor each key point of the first empty cable state with reference to the second empty cable state, and output a key point adjustment strategy.

[0028] For example, a spatial cable-plane suspension bridge is a three-dimensional cable system consisting of main cables, suspenders and stiffening beams, and the main cable line shape is a spatial structure, such as Figure 2 As shown, its projection on the facade is a parabola, such as Figure 3 As shown, its projection on the plane is also a parabola.

[0029] In bridge monitoring, data acquisition equipment is crucial and is used to monitor key parameters of the bridge in real time. The multiple data acquisition devices 101 can be radar scanning devices, temperature sensors, etc. carried by drones. The radar scanning equipment carried by drones can fully scan the space cable surface suspension bridge in the empty cable state. Figure 4 As shown in the figure, the empty cable state of the space cable suspension bridge is the stage during the construction of the suspension bridge, after the main cable is installed in place, but before the suspenders and stiffening beams are installed. The temperature sensor can obtain the temperature at different spans. The span of the space cable suspension bridge can be divided into the middle span and the side span. The middle span refers to the longest span in the suspension bridge, that is, the main span, which is the main span connecting the two bridge towers. The side span refers to the shorter spans on both sides of the main span in the suspension bridge. They connect the bridge towers with the anchors or abutments. The main function of the side span is to transfer the load of the main span to the anchors or abutments and maintain the stability of the entire bridge structure.

[0030] The first empty cable state determination device 102 determines the first empty cable state according to the target data collected by multiple data acquisition devices, wherein the first empty cable state can be the main cable line shape in the empty cable state. According to the three-dimensional point cloud data acquired by the radar scanning device carried by the drone, the main cable line shape in the empty cable state can be determined by: reconstructing the point cloud data model to obtain the empty cable state model of the space cable surface suspension bridge, and then extracting the main cable line shape in the empty cable state model of the space cable surface suspension bridge. The main cable line shape will be affected by thermal expansion and contraction, and the temperature of each span acquired by the temperature sensor can be used for temperature calibration to provide a reference for subsequent analysis. That is, the first empty cable state can be the main cable line shape in the empty cable state at a certain temperature. In addition, the first empty cable state can also be determined according to the target data acquired by different data acquisition devices. For example, when the target data acquired by the target acquisition device is the pier shape data in the empty cable state, the first empty cable state can be the pier shape. This embodiment does not limit the target data and the corresponding first empty cable state, and those skilled in the art can determine it as needed.

[0031] The second empty cable state simulation device 103 is used to simulate and determine the second empty cable state of the space cable suspension bridge that meets the construction standards. The specific process can be to take the completed bridge state as the initial state and dismantle the structure in reverse according to the process that is completely opposite to the actual construction and erection sequence. First, remove the bridge deck pavement, and then remove the stiffening beam sections one by one, and finally only the main cable, saddle, and main tower are left. The equilibrium state of each stage is calculated one by one, and finally the empty cable state of the suspension bridge is obtained, so as to determine the various required parameters in this state, which may include the main cable line shape, bridge pier shape, etc.

[0032] The key point monitoring device 104 is used to monitor the key points of the first empty cable state with reference to the second empty cable state, and output the key point adjustment strategy. The key point can be any position of the suspension bridge, and the monitoring of the key point includes changes in a specific position, such as changes in the shape of the pier, the lateral deviation of the sling, the lateral deflection of the sling, or the changes in the main cable line shape. The key point can be a position of user concern pre-set by the user, or it can be a position where a large difference occurs when comparing the second empty cable state with the first empty cable state. The key point adjustment strategy can be to display the parameter difference of the key point in the first empty cable state and the second empty cable state, and use the second empty cable state as the standard state to prompt the user to adjust the parameter difference.

[0033] An embodiment of the present invention provides a system for monitoring the linear shape of empty cables of a space cable surface suspension bridge. Compared with comparing a first empty cable state with a completed bridge model, this embodiment takes into account the difference in changes of the space cable surface suspension bridge at different stages, and adopts a second empty cable state simulation device to simulate and determine the second empty cable state of the space cable surface suspension bridge that meets the construction standards. By simulating the empty cable state and comparing the first empty cable state with the second empty cable state, key points are determined, and adjustment strategies are output, thereby improving the accuracy and safety of construction, optimizing the construction control process, and ultimately improving the overall performance and construction quality of the bridge.

[0034] As an optional implementation, multiple data acquisition devices include: a radar scanning device carried by a drone, used to obtain point cloud data of the space cable surface suspension bridge in the empty cable state;

[0035] The first empty cable state includes a main cable line shape, and the first empty cable state is determined according to target data collected by multiple data collection devices, including:

[0036] The point cloud data is reconstructed into a model to obtain the empty cable state model of the space cable surface suspension bridge; according to the design model of the space cable surface suspension bridge, the spatial area of ​​the main cable in the design model of the space cable surface suspension bridge is determined; according to the scaling ratio of the empty cable state model of the space cable surface suspension bridge and the design model of the space cable surface suspension bridge, the spatial area of ​​the main cable in the design model of the space cable surface suspension bridge is synchronously scaled to determine the spatial area of ​​the main cable in the empty cable state model of the space cable surface suspension bridge; the spatial area of ​​the main cable in the empty cable state model of the space cable surface suspension bridge is taken as the region of interest, and the point cloud data in the region is extracted; the target line is determined in the target point cloud set; the target line is subjected to curve smoothing to obtain the main cable line shape.

[0037] Exemplarily, the model reconstruction utilizes the point cloud processing and three-dimensional reconstruction technology in the CGAL library to reconstruct the point cloud data and obtain the empty cable state model of the space cable-surface suspension bridge. According to the design model of the space cable-surface suspension bridge, the span of the middle span and the height of the bridge towers on both sides, the highest navigation water level height and the width of the widest position on the side can be obtained. According to the span of the middle span and the height of the bridge towers on both sides, the highest navigation water level height and the width of the widest position on the side, a spatial area is delineated. The spatial area can be a rectangular parallelepiped, and the spatial area is taken as the first spatial area. At the same time, the second spatial area is determined according to each point of the space cable-surface suspension bridge design model that is farthest from the center of the suspension bridge. The second spatial area is a spatial area that just contains the entire space cable-surface suspension bridge design model. The spatial area can also be a rectangular parallelepiped. According to the positional relationship between the first spatial area and the second spatial area, the spatial area occupied by the main cable in the space cable-surface suspension bridge design model can be determined.

[0038] Since the empty cable state model of the space cable plane suspension bridge and the design model of the space cable plane suspension bridge may be models of different scales, the spatial region of the main cable in the design model of the space cable plane suspension bridge can be synchronously scaled according to the scaling ratio of the empty cable state model of the space cable plane suspension bridge and the design model of the space cable plane suspension bridge to determine the spatial region of the main cable in the empty cable state model of the space cable plane suspension bridge. The spatial region of the main cable in the empty cable state model is taken as the region of interest, and the point cloud data in the region is extracted.

[0039] Using clustering algorithms, such as K-means or density-based clustering algorithms, the target lines can be determined in the target point cloud set. The clustering algorithm distinguishes different lines by calculating the distance between the point and the centroid and assigning the point to the nearest centroid. To smooth the curve of the target line, you can use the jet_smooth_point_set function in the CGAL library to obtain the main cable shape. Smoothing helps reduce data noise and improve the accuracy of the line shape.

[0040] An embodiment of the present invention provides a system for monitoring the linear shape of an empty cable of a spatial cable-surface suspension bridge. When performing linear shape extraction, the spatial area of ​​the main cable in the empty cable state model of the spatial cable-surface suspension bridge further reduces the point cloud data that needs to be processed, thereby improving the linear shape extraction efficiency.

[0041] As an optional implementation, a target line is determined in a target point cloud set, and a curve smoothing process is performed on the target line to obtain a main cable line shape, including: extracting a target point cloud subset with linear features from the target point cloud set; determining a distribution direction vector of target point cloud data in the target point cloud subset according to a principal component analysis method; judging whether the distribution direction vector of the target point cloud data satisfies a linear constraint condition, and if so, clustering the target point cloud data according to a clustering algorithm to obtain a main cable line shape, wherein the linear constraint condition is that there are multiple direction vectors whose dot products with a horizontal vector gradually increase, and there are multiple direction vectors whose dot products with a horizontal vector gradually decrease.

[0042] For example, the main distribution direction of the data can be determined by analyzing the target point cloud set using principal component analysis (PCA). PCA finds the direction with the largest data change, i.e., the principal component, by calculating the covariance matrix and eigenvalue decomposition. These principal component direction vectors can represent the main trends of the point cloud data, thereby identifying a subset of point clouds with linear features. The eigenvectors obtained by PCA are the distribution direction vectors of the target point cloud data, which indicate the main directions of the data point distribution.

[0043] The linear constraint condition involves the change of the dot product of the direction vector and the horizontal vector. If there are multiple direction vectors and the dot product of the horizontal vector gradually increases or decreases, this indicates that the distribution of the target point cloud data in space presents a specific linear trend. This trend can be used to determine whether the target point cloud data meets the linear constraint condition. Specifically, the dot product of the direction vector and the horizontal line gradually increases, which means that the angle between the direction vector and the horizontal line is decreasing, that is, the direction vector is getting closer and closer to the horizontal line. Because when the angle between the direction vector and the horizontal line decreases, the value of the cosine function increases, resulting in an increase in the dot product. The dot product of the direction vector and the horizontal line gradually decreases in the same way, so it will not be repeated. The shape change of the main cable is effectively constrained by calculating the dot product of the direction vector and the horizontal line.

[0044] When the distribution direction vector of the target point cloud data satisfies the linear constraint, clustering algorithms (such as DBSCAN, K-Means, etc.) can be applied to cluster the target point cloud data. These algorithms can divide the data into different clusters according to the spatial distribution characteristics of the point cloud data, thereby obtaining the main cable shape. The clustering result will show the main cable shape, that is, the clusters of points with similar directions and positions in the point cloud data.

[0045] An embodiment of the present invention provides a spatial cable-surface suspension bridge empty cable linearity monitoring system. By extracting a target point cloud subset with linear features from a target point cloud set, point cloud data related to the main cable can be quickly located, thereby improving the efficiency and accuracy of data processing. The linear constraint conditions ensure that only point cloud data that meets specific linear features are used for subsequent clustering analysis, thereby enhancing the accuracy and reliability of the results.

[0046] As an optional implementation, a space cable plane suspension bridge empty cable linear monitoring system includes: a distributed temperature sensor for obtaining the temperature of each span of the suspension bridge;

[0047] The first empty cable state also includes the transverse bridge coordinates of a preset suspension point in the empty cable state or the transverse inclination angle of a line connecting the upper and lower suspension points of the sling in the empty cable state. The first empty cable state is determined according to target data collected by multiple data collection devices, including:

[0048] For the transverse coordinates of the preset slings in the empty cable state, according to the temperature of the corresponding span and the influence of the temperature on the length of the main cable, the original coordinates of the preset slings on the main cable are adjusted to obtain the target coordinates of the slings, and the target coordinates of the slings in the empty cable state model of the spatial cable plane suspension bridge are marked to determine the transverse coordinates of the marked points in the empty cable state model of the spatial cable plane suspension bridge; or,

[0049] For the lateral inclination angle of the line connecting the upper and lower hanging points of the cable in the empty cable state, the original coordinates of the preset cable on the main cable are adjusted according to the temperature of the corresponding span and the influence of the temperature on the length of the main cable to obtain the target coordinates of the cable, and the target coordinates of the cable are connected with the coordinates of the lower anchor point of the original cable to obtain the connecting line, and the angle between the connecting line and the horizontal plane is determined as the lateral inclination angle of the line connecting the upper and lower hanging points of the cable in the empty cable state.

[0050] Exemplarily, in this embodiment, the influence of the current temperature on the coordinates of the slings arranged on the main cable is considered. Specifically, the formula (linear expansion formula) for the influence of temperature change on the length of the main cable is as follows:

[0051] ;

[0052] in, is the change in the length of the main cable, is the original length of the main cable, is the linear expansion coefficient of the main cable material, It is the temperature change.

[0053] After obtaining the target coordinates of the sling, mark the target coordinates of the sling in the empty cable state model of the space cable plane suspension bridge to determine the transverse coordinates of the marked points in the empty cable state model of the space cable plane suspension bridge. The above process is to monitor the temperature monitoring data of each temperature monitoring point on the reference cable, and send the temperature monitoring data of each temperature monitoring point to the computer unit, the computer unit obtains the temperature monitoring data of each temperature monitoring point for judgment and processing, obtains the average temperature change of each temperature monitoring point, and calculates the target coordinates of the sling according to the average temperature change of each span.

[0054] According to the temperature of the corresponding span and the effect of temperature on the length of the main cable, adjust the original coordinates of the preset sling on the main cable to obtain the target coordinates of the sling. Connect the target coordinates of the sling with the coordinates of the anchor point of the original sling to obtain a connecting line. Determine the angle between the connecting line and the horizontal plane as the lateral inclination of the line connecting the upper and lower suspension points of the sling in the empty cable state.

[0055] As an optional implementation manner, the second empty cable state simulation device performs the following steps, including:

[0056] Mark the target coordinates of the cables of the adjusted completed model of the space cable-surface suspension bridge, and determine the transverse coordinates of the marked points in the adjusted completed model of the space cable-surface suspension bridge; or,

[0057] In the adjusted spatial cable-surface suspension bridge model, the target coordinates of the cable and the coordinates of the lower anchor point of the original cable are connected to obtain a connecting line, and the angle between the connecting line and the horizontal plane is determined as the lateral inclination angle of the line connecting the upper and lower suspension points of the cable in the spatial cable-surface suspension bridge model.

[0058] Exemplarily, due to the empty cable state and completed bridge state of the space cable surface suspension bridge, the main cable line shape will undergo significant changes. In this embodiment, by determining the target coordinates of the suspension cables in the adjusted completed bridge model of the space cable surface suspension bridge, and obtaining the transverse bridge coordinates of the marking points, combined with the transverse bridge coordinates of the marking points in the empty cable state model of the space cable surface suspension bridge in the above embodiment, the lateral deviation of the cables in the two bridge states can be obtained. When the lateral deviation exceeds the allowable range, it means that there is a large construction error at present, and the construction content and the current bridge need to be adjusted.

[0059] Similarly, the target coordinates of the cable and the coordinates of the lower anchor point of the original cable can be connected in the adjusted spatial cable-surface suspension bridge model to obtain a connecting line, and the angle between the connecting line and the horizontal plane can be determined as the lateral inclination angle of the line connecting the upper and lower suspension points of the cable in the spatial cable-surface suspension bridge model. Combined with the lateral inclination angle of the line connecting the upper and lower suspension points of the cable in the empty cable state in the above-mentioned embodiment, the lateral deviation angle of the cable in the two bridge states can be obtained. By comparing whether the lateral deviation angle exceeds the allowable range, it is determined whether the current construction has a large error or whether the current construction content needs to be adjusted.

[0060] An embodiment of the present invention provides a system for monitoring the linear shape of an empty cable of a space cable plane suspension bridge, which takes into account the influence of temperature on the length of the main cable, so that the influence of temperature is unified in the empty cable state model of the space cable plane suspension bridge and in the completed bridge model of the space cable plane suspension bridge, thereby reducing the error of the lateral deviation angle of the cable under the two bridge states or the lateral deviation of the cable under the two bridge states, and improving the accuracy.

[0061] As an optional implementation manner, the second empty cable state simulation device performs the following steps, including:

[0062] According to the design drawings of the spatial cable-surface suspension bridge, the MIDAS Civil tool was used to construct the completed bridge model of the spatial cable-surface suspension bridge.

[0063] Input the target temperature control command in each span of the spatial cable-surface suspension bridge model, and adjust the length of the main cable in each span of the spatial cable-surface suspension bridge model according to the relationship between the temperature and the main cable length. The temperature controlled by the target temperature control command is the corresponding temperature obtained by the distributed temperature sensor.

[0064] The segmented catenary analysis theory is used to analyze the adjusted spatial cable-surface suspension bridge model to determine the stress-free length of the main cable, the coordinates of the suspension points and the state of the suspension cables, and the pre-deflection and elevation of the cable saddle for the installation of the empty cable.

[0065] According to the stress-free length of the main cable, the coordinates of the suspension points and the state of the suspension cables, the pre-deflection and elevation of the saddle for installing the empty cable, the linear shape of the empty cable of the spatial cable surface suspension bridge is determined at the target temperature.

[0066] For example, using the MIDAS Civil tool, first define the material and cross-sectional property values ​​of the main cables, bridge towers, beams, stiffening beams, diaphragms, etc. Then, click the "Suspension Bridge Modeling Assistant" in the Structure-Suspension Bridge button, enter relevant information, and use the Modeling Assistant function to generate a preliminary model.

[0067] In the bridge model, each span inputs the target temperature control instructions, which are based on the corresponding temperature obtained by the distributed temperature sensor. According to the relationship between temperature and main cable length, the length of the main cable in each span is adjusted. The linear expansion formula can be used to calculate the length change, see the formula for the effect of temperature change on the main cable length in the previous embodiment.

[0068] The segmented catenary analysis theory is used to analyze the adjusted suspension bridge model. The segmented catenary analysis theory assumes that the geometric shape of the main cable of each span is a segmented catenary, which is consistent with the actual situation. Specifically, it is first assumed that the flexible cable can only be subjected to tension, not compression or bending; the stress-strain of the flexible cable conforms to Hooke's law; the calculation of the tensile stiffness of the main cable (flexible cable) before and after force is based on the cross-sectional area of ​​the main cable before deformation; in the same cable segment, the cable only bears a vertical uniformly distributed load along the cable length before deformation, and the concentrated load can only act on the two ends of the cable segment (the nodes between adjacent cable segments). Then the main cable is divided into several segments, and the relationship between the linear shape and internal force of each cable segment can be expressed by the following equation:

[0069] ;

[0070] ;

[0071] ;

[0072] ;

[0073] in, and is the starting coordinate of any segment, The two end points of the cable segment Span, which is the length adjusted by the temperature-dependent linear expansion formula, is the height difference, is the stress-free length of the cable segment, is the cable tension at the left end of the cable segment, , , represents the horizontal component of force at the left end, represents the horizontal component of force at the right end, represents the vertical component of the left end, represents the vertical component of the right end, is the tension of the cable segment at the right end, E is the elastic modulus, A is the cross-sectional area, It represents the self-weight uniformly distributed load of the main cable in the stress-free state. The above formula is calculated by numerical iteration method to obtain the solution that meets the elevation requirements of the end and middle points of the main cable, so as to obtain the main cable line shape.

[0074] The embodiment of the present invention provides a system for monitoring the linear shape of an empty cable of a space cable suspension bridge. The temperature data obtained by the distributed temperature sensor can be used to adjust the length of the main cable in the completed bridge model of the space cable suspension bridge in real time. This real-time temperature control can ensure the precise adjustment of the length of the main cable to adapt to the impact of temperature changes. And according to the parameters such as the stress-free length of the main cable, the coordinates of the suspension point and the state of the sling, the pre-bias and elevation of the empty cable installation saddle, the linear shape of the empty cable of the space cable suspension bridge at the target temperature can be determined, which helps to improve the accuracy and efficiency of the construction and reduce errors and rework during the construction process.

[0075] As an optional implementation, each key point of the first empty cable state is monitored with reference to the second empty cable state, and a key point adjustment strategy is output, including: calculating the difference between the parameters of each key point in the second empty cable state and the parameters in the first empty cable state to obtain the difference value of each key point; inputting the key point into the knowledge graph to search for the influencing factors related to the key point; adjusting the parameters of each influencing factor of the spatial cable surface suspension bridge model in the first empty cable state according to the finite element analysis method until the key point difference value corresponding to each influencing factor is less than a preset threshold; outputting the adjusted influencing factors and the parameters of the influencing factors as the key point adjustment strategy.

[0076] Exemplarily, the difference between the parameters of each key point in the second empty cable state and the parameters in the first empty cable state is calculated to obtain the difference value of each key point, wherein the key point can be the main cable or the preset sling, and the parameter of the key point can be the main cable line shape, the transverse bridge coordinate of the preset sling, or the transverse inclination of the line connecting the upper and lower suspension points of the sling. The change of the parameters in the two states is calculated as the difference value of the key point.

[0077] The knowledge graph can store and process a large amount of structured data. Through the graph, relevant data can be quickly queried and associated. The knowledge graph is pre-stored in the key point monitoring device. Its construction process includes: first, the text or structured data related to the space cable-surface suspension bridge is obtained from the Internet public data set or academic literature, and the data is cleaned. Then, natural language processing technology, such as named entity recognition (NER), is used to extract key entities (such as bridge components, environmental factors, etc.) and relationships (such as geometric relationships, mechanical connections, etc.) from the collected data. Then, a domain ontology is constructed to define the shared concepts, entities and relationships between them in the bridge field. Ontology construction is the core component of the knowledge graph, and formal languages ​​(such as OWL) can be used for standardized representation and storage. According to the ontology structure, the extracted entities and relationships are stored in the graph database in the form of triples. By entering the key points into the knowledge graph, the influencing factors related to the key points can be searched.

[0078] In the ANSYS analysis software, the parameters corresponding to the influencing factors related to the key points are adjusted so that the spatial cable-surface suspension bridge model in the first empty-cable state in the ANSYS analysis software continuously approaches the spatial cable-surface suspension bridge in the second empty-cable state, until the key point difference values ​​corresponding to the various influencing factors are less than a preset threshold value, which may be 5%. This embodiment does not limit the size of the preset threshold value, and those skilled in the art may determine it according to actual needs; the adjusted influencing factors and the parameters of the influencing factors are output as key point adjustment strategies.

[0079] An embodiment of the present invention provides a spatial cable-surface suspension bridge empty cable linear monitoring system, which applies knowledge graphs and finite element analysis methods to determine the fundamental cause of the difference between the parameters of key points in the second empty cable state and the parameters in the first empty cable state, and gives users specific prompts. Users no longer need to analyze the reasons based on the difference values, thereby improving the intelligence of the system.

[0080] Finally, it should be noted that the above preferred embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail through the above preferred embodiments, those skilled in the art should understand that various changes can be made in form and details without departing from the scope defined by the claims of the present invention.

Claims

1. A linear monitoring system for empty cables of a space cable-surface suspension bridge, characterized in that: include: Multiple data acquisition devices are used to collect target data when the space cable suspension bridge is in the empty cable state; A first empty cable state determining device is used to determine a first empty cable state according to target data collected by a plurality of data collection devices, wherein the first empty cable state includes first empty cable state parameters, wherein the first empty cable state parameters include the main cable line shape in the empty cable state, or the first empty cable state parameters include the main cable line shape in the empty cable state and the transverse bridge coordinates of a preset suspension point in the empty cable state, or the first empty cable state parameters include the main cable line shape in the empty cable state and the transverse inclination angle of a line connecting the upper and lower suspension points of the sling in the empty cable state; A second empty cable state simulation device is used to simulate and determine a second empty cable state of a space cable surface suspension bridge that meets construction standards. The second empty cable state is the empty cable state of the space cable surface suspension bridge obtained by dismantling the structure in reverse according to a process that is completely opposite to the actual construction and erection sequence, taking the completed bridge state as the initial state. The second empty cable state includes second empty cable state parameters. The second empty cable state parameters include the main cable line shape of the simulated space cable surface suspension bridge in the empty cable state, or the second empty cable state parameters include the main cable line shape of the simulated space cable surface suspension bridge in the empty cable state and the transverse bridge coordinates of the marked points in the completed model of the space cable surface suspension bridge, or the second empty cable state parameters include the main cable line shape of the simulated space cable surface suspension bridge in the empty cable state and the transverse inclination angle of the line connecting the upper and lower suspension points of the sling in the completed model of the space cable surface suspension bridge; The key point monitoring device is used to monitor each key point of the first empty cable state with reference to the second empty cable state, and output a key point adjustment strategy.

2. A linear monitoring system for empty cables of a space cable-surface suspension bridge according to claim 1, characterized in that: Multiple data acquisition devices, including: The radar scanning equipment carried by the drone is used to obtain point cloud data of the space cable suspension bridge in the empty cable state; The first empty cable state parameter includes the main cable line shape, and the first empty cable state is determined according to target data collected by multiple data collection devices, including: The point cloud data is reconstructed to obtain the empty cable state model of the space cable-surface suspension bridge; According to the design model of the spatial cable-surface suspension bridge, the spatial area of ​​the main cable in the design model of the spatial cable-surface suspension bridge is determined; According to the scaling ratio of the empty cable state model of the space cable plane suspension bridge and the design model of the space cable plane suspension bridge, the spatial area of ​​the main cable in the empty cable state model of the space cable plane suspension bridge is determined; Extract the point cloud data of the main cable in the space region of the empty cable state model of the space cable plane suspension bridge as the target point cloud set; The target line is determined in the target point cloud set, and the target line is subjected to curve smoothing to obtain the main cable shape.

3. A linear monitoring system for empty cables of a space cable-surface suspension bridge according to claim 2, characterized in that: include: Distributed temperature sensors are used to obtain the temperature of each span of the suspension bridge; The first empty cable state parameter also includes the transverse bridge coordinates of a preset suspension point in the empty cable state or the transverse inclination angle of the line connecting the upper and lower suspension points of the sling in the empty cable state. The first empty cable state is determined according to target data collected by multiple data acquisition devices, including: For the transverse coordinates of the preset slings in the empty cable state, according to the temperature of the corresponding span and the influence of the temperature on the length of the main cable, the original coordinates of the preset slings on the main cable are adjusted to obtain the target coordinates of the slings, and the target coordinates of the slings in the empty cable state model of the spatial cable plane suspension bridge are marked to determine the transverse coordinates of the marked points in the empty cable state model of the spatial cable plane suspension bridge; or, According to the lateral inclination angle of the line connecting the upper and lower hanging points of the cable in the empty cable state, the original coordinates of the preset cable on the main cable are adjusted according to the temperature of the corresponding span and the influence of temperature on the length of the main cable to obtain the target coordinates of the cable. The target coordinates of the cable and the coordinates of the lower anchor point of the original cable are connected in the empty cable state model of the spatial cable surface suspension bridge to obtain the connecting line, and the angle between the connecting line and the horizontal plane is determined as the lateral inclination angle of the line connecting the upper and lower hanging points of the cable in the empty cable state.

4. A linear monitoring system for empty cables of a space cable-surface suspension bridge according to claim 3, characterized in that: The second empty cable state simulation device performs the following steps, including: According to the design drawings of the spatial cable-surface suspension bridge, the MIDAS Civil tool was used to construct the completed bridge model of the spatial cable-surface suspension bridge. Input the target temperature control command in each span of the spatial cable-surface suspension bridge model, and adjust the length of the main cable in each span of the spatial cable-surface suspension bridge model according to the relationship between the temperature and the main cable length. The temperature controlled by the target temperature control command is the corresponding temperature obtained by the distributed temperature sensor. The segmented catenary analysis theory is used to analyze the adjusted suspension bridge model to determine the stress-free length of the main cable, the coordinates of the suspension points and the state of the suspension cables, and the pre-deflection and elevation of the cable saddle for the installation of the empty cable. According to the stress-free length of the main cable, the coordinates of the suspension points and the state of the suspension cables, the pre-deflection and elevation of the saddle for installing the empty cable, the linear shape of the empty cable of the spatial cable surface suspension bridge is determined at the target temperature.

5. The linear monitoring system for empty cables of a space cable-surface suspension bridge according to claim 4 is characterized in that: The second empty cable state simulation device performs the following steps, including: Mark the target coordinates of the suspension cables in the completed model of the spatial cable-surface suspension bridge, and determine the transverse coordinates of the marked points in the completed model of the spatial cable-surface suspension bridge; or, In the completed model of the spatial cable-surface suspension bridge, the target coordinates of the cable and the coordinates of the lower anchor point of the original cable are connected to obtain a connecting line, and the angle between the connecting line and the horizontal plane is determined as the lateral inclination angle of the line connecting the upper and lower suspension points of the cable in the completed model of the spatial cable-surface suspension bridge.

6. The linear monitoring system for empty cables of a space cable-surface suspension bridge according to claim 2 is characterized in that: Determine the target line in the target point cloud set, perform curve smoothing on the target line, and obtain the main cable shape, including: Extracting a target point cloud subset having linear features from the target point cloud set; Determine the distribution direction vector of the target point cloud data in the target point cloud subset according to the principal component analysis method; It is determined whether the distribution direction vector of the target point cloud data satisfies the linear constraint condition. If it does, the target point cloud data is clustered according to the clustering algorithm to obtain the main cable linear shape, where the linear constraint condition is that there are multiple direction vectors whose dot products with the horizontal vector gradually increase and there are multiple direction vectors whose dot products with the horizontal vector gradually decrease.

7. A linear monitoring system for empty cables of a space cable-surface suspension bridge according to any one of claims 1 to 6, characterized in that: Monitor each key point of the first empty cable state with reference to the second empty cable state, and output key point adjustment strategies, including: Calculate the difference between the parameters of each key point in the second empty-cable state and the parameters in the first empty-cable state to obtain the difference value of each key point; Input the key points into the knowledge graph and search for the influencing factors related to the key points; According to the finite element analysis method, the parameters of various influencing factors of the spatial cable-surface suspension bridge model in the first empty-cable state are adjusted until the difference value of the key points corresponding to each influencing factor is less than a preset threshold; The adjusted influencing factors and their parameters are output as key point adjustment strategies.

Images