CN116363640A - Cable force identification method, equipment and storage medium based on three-dimensional point cloud - Google Patents
Cable force identification method, equipment and storage medium based on three-dimensional point cloud Download PDFInfo
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Abstract
The invention relates to the technical field of point cloud data processing, in particular to a three-dimensional point cloud-based inhaul cable force identification method, equipment and storage medium. According to the invention, firstly, dimension reduction preprocessing is carried out on three-dimensional point cloud data for representing positions of points on a inhaul cable, so as to obtain two-dimensional data of the positions of the points. And then calculating the horizontal span and the elevation difference between any two points according to the two-dimensional data of the positions of the points. And finally, calculating the external tension between any two points on the inhaul cable according to the horizontal span, the elevation difference, the two-dimensional data of the positions of each point and the gravity of the inhaul cable. According to the analysis, the external tension force received by each point on the inhaul cable is directly calculated through the three-dimensional point cloud data, and the three-dimensional point cloud data is acquired without an instrument arranged on the inhaul cable, so that the difficulty in measuring the tension force of the inhaul cable is reduced.
Description
Technical Field
The invention relates to the technical field of point cloud data processing, in particular to a three-dimensional point cloud-based inhaul cable force identification method, equipment and storage medium.
Background
The existing cable force testing method of the cable-stayed bridge mainly comprises a hydraulic meter method, a cable elongation measuring method, a pressure sensor method, a magnetic flux method, a vibration frequency method and the like. The hydraulic meter method and the cable elongation measuring method are generally only used for measuring the cable force in the tensioning construction process of the cable, and cannot measure the tensioned cable. The pressure sensor method has the advantages that the price of the pressure sensor is high, the pressure sensor has large self weight, the pressure sensor needs to be embedded in advance in the construction stage, and the output result has offset, so that the application of the method in cable force detection and long-term monitoring is limited. The magnetic flux method needs to measure the characteristics of the inhaul cable material in advance and place a small electromagnetic sensor in the inhaul cable, so that the inhaul cable material can be used for measuring the cable force of a bridge in the construction process. The accuracy of the test results of the vibration frequency method is very dependent on the experience of the tester and is affected by the length of the cable, the constraints at both ends, the bending stiffness and sagging of the cable, and other external factors. From the above analysis, in the prior art, when measuring the cable force of the cable (the external tension applied to the cable), the measuring instrument needs to be placed on the cable to measure the tension applied to the cable, so as to improve the measuring difficulty.
In summary, the existing inhaul cable force measuring method improves the measuring difficulty.
Accordingly, there is a need for improvement and advancement in the art.
Disclosure of Invention
In order to solve the technical problems, the invention provides a three-dimensional point cloud-based inhaul cable force identification method, equipment and a storage medium, which solve the problem that the existing inhaul cable force measurement method improves the measurement difficulty.
In order to achieve the above purpose, the present invention adopts the following technical scheme:
in a first aspect, the present invention provides a method for identifying a cable force of a cable based on a three-dimensional point cloud, including:
preprocessing three-dimensional point cloud data of a guy cable to obtain two-dimensional data of the guy cable, wherein the three-dimensional point cloud data are used for representing three-dimensional coordinate information of each point on the guy cable;
according to the two-dimensional data of the inhaul cable, the horizontal span of the inhaul cable in the horizontal direction and the elevation difference of the inhaul cable in the vertical direction are obtained;
and obtaining the tension value of the inhaul cable according to the horizontal span, the elevation difference, the gravity of the inhaul cable and the two-dimensional data of the inhaul cable.
In one implementation manner, the preprocessing is performed on the three-dimensional point cloud data of the inhaul cable to obtain two-dimensional data of the inhaul cable, where the three-dimensional point cloud data is used for representing three-dimensional coordinate information of each point on the inhaul cable, and the preprocessing includes:
determining the projection of one end part of the inhaul cable on the horizontal plane where the other end part is positioned, and marking the projection as a projection point;
establishing a plane equation of the inhaul cable according to the coordinates of the two end parts and the coordinates of the projection points;
projecting the three-dimensional point cloud data of the inhaul cable to a plane in which the plane equation is located, so as to obtain preselected two-dimensional data of the inhaul cable;
constructing a fitting curve of the inhaul cable according to the preselected two-dimensional data;
and selecting the two-dimensional data positioned on the fitting curve from the preselected two-dimensional data to obtain the final two-dimensional data of the inhaul cable.
In one implementation manner, the obtaining, according to the two-dimensional data of the cable, a horizontal span of the cable in a horizontal direction and an elevation difference of the cable in a vertical direction includes:
determining two-dimensional data of each point on the inhaul cable in the two-dimensional data of the inhaul cable, wherein the two-dimensional data of each point is used for representing coordinates of each point in a two-dimensional coordinate system;
and determining the horizontal span and the elevation difference between any two points on the inhaul cable according to the two-dimensional data of each point on the inhaul cable.
In one implementation, the gravity of the cable is the dead weight of the cable in unit length, and the pulling force value of the cable is obtained according to the horizontal span, the elevation difference, the gravity of the cable and the two-dimensional data of the cable, including:
obtaining a first angle according to the ratio of the product of the gravity of the inhaul cable and the horizontal span to the constructed tension parameter;
determining a ratio of the elevation difference to the horizontal span, and recording the ratio as a first ratio;
determining the ratio of the product of the first angle and the first ratio to the hyperbolic sine function of the first angle, and recording the ratio as a second ratio;
obtaining a second angle according to the inverted hyperbolic sine function of the second ratio and the first angle;
constructing a cable model related to the tension parameter according to the second angle, the first angle, the horizontal span between any two points on the cable, the gravity of the cable and the coordinates of any two points on the cable;
and obtaining a tension value between any two points on the inhaul cable by solving the tension parameter in the inhaul cable model.
In one implementation, the tension parameter is a horizontal split tension parameter, and constructing a cable model related to the tension parameter according to the second angle, the first angle, the horizontal span between any two points on the cable, the gravity of the cable, and the coordinates of any two points on the cable includes:
determining the ratio of the product of the first angle and the abscissa of any two points on the inhaul cable to the horizontal span, and recording the ratio as a third ratio;
and constructing a cable model related to the tension parameter according to the hyperbolic cosine function of the second angle, the hyperbolic cosine function of the third ratio, the second angle, the ratio of the tension parameter to the gravity and the ordinate of any two points on the cable.
In one implementation manner, the tension value is a tension value in a horizontal direction, and the tension value between any two points on the inhaul cable is obtained by solving the tension parameter in the inhaul cable model, and then the method further comprises:
determining a negative value of an anti-hyperbolic sine function of the difference between the third ratio and the second angle, and recording the negative value as a tangent value;
obtaining the inclination angle of a straight line formed by any two points on the inhaul cable relative to the horizontal direction according to the arc tangent function of the tangent value;
and obtaining the tension value between any two points on the inhaul cable along the tangential direction of the inhaul cable according to the tension value in the horizontal direction and the inclination angle.
In one implementation manner, the obtaining the tension value between any two points on the inhaul cable along the tangential direction of the inhaul cable according to the tension value in the horizontal direction and the inclination angle includes:
establishing a regression model of two-dimensional data of any two points on the inhaul cable with respect to tension parameters in the horizontal direction;
inputting a tension set value corresponding to the tension parameter into the regression model;
performing first-order Taylor expansion on the regression model input with the tension set value to obtain a first-order Taylor expansion;
obtaining a final tension value of the inhaul cable in the horizontal direction according to the first-order Taylor expansion;
correcting the inclination angle according to the final tension value;
and obtaining a final tension value between any two points on the inhaul cable along the tangential direction of the inhaul cable according to the corrected inclination angle.
In one implementation, the method further comprises:
taking a point corresponding to the final two-dimensional data of the inhaul cable as a control point;
creating a three-dimensional curve of the inhaul cable according to the control points;
performing offset in a set direction on the three-dimensional curve to obtain the three-dimensional curve after a plurality of offsets;
and constructing a BIM model of the inhaul cable according to the three-dimensional curves after the deviations.
In a second aspect, an embodiment of the present invention further provides a terminal device, where the terminal device includes a memory, a processor, and a three-dimensional point cloud-based cable force identification program stored in the memory and capable of running on the processor, and when the processor executes the three-dimensional point cloud-based cable force identification program, the steps of the three-dimensional point cloud-based cable force identification method are implemented.
In a third aspect, an embodiment of the present invention further provides a computer readable storage medium, where a three-dimensional point cloud-based cable force identification program is stored on the computer readable storage medium, and when the three-dimensional point cloud-based cable force identification program is executed by a processor, the steps of the three-dimensional point cloud-based cable force identification method are implemented.
The beneficial effects are that: according to the invention, firstly, dimension reduction preprocessing is carried out on three-dimensional point cloud data for representing positions of points on a inhaul cable, so as to obtain two-dimensional data of the positions of the points. And then calculating the horizontal span and the elevation difference between any two points according to the two-dimensional data of the positions of the points. And finally, calculating the external tension between any two points on the inhaul cable according to the horizontal span, the elevation difference, the two-dimensional data of the positions of each point and the gravity of the inhaul cable. According to the analysis, the external tension force received by each point on the inhaul cable is directly calculated through the three-dimensional point cloud data, and the three-dimensional point cloud data is acquired without an instrument arranged on the inhaul cable, so that the difficulty in measuring the tension force of the inhaul cable is reduced.
Drawings
FIG. 1 is an overall flow chart of the present invention;
FIG. 2 is a flow chart of a point cloud normalization process in an embodiment of the present invention;
FIG. 3 is a schematic view of a cable in a three-dimensional coordinate system according to an embodiment of the present invention;
FIG. 4 is a schematic diagram of a cable in a two-dimensional coordinate system according to an embodiment of the present invention;
FIG. 5 is a flow chart of a digital twinning technique in an embodiment of the invention;
fig. 6 is a schematic block diagram of an internal structure of a terminal device according to an embodiment of the present invention.
Detailed Description
The technical scheme of the invention is clearly and completely described below with reference to the examples and the drawings. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
The research shows that the current cable-stayed bridge cable force testing method mainly comprises a hydraulic meter method, a cable elongation measuring method, a pressure sensor method, a magnetic flux method, a vibration frequency method and the like. The hydraulic meter method and the cable elongation measuring method are generally only used for measuring the cable force in the tensioning construction process of the cable, and cannot measure the tensioned cable. The pressure sensor method has the advantages that the price of the pressure sensor is high, the pressure sensor has large self weight, the pressure sensor needs to be embedded in advance in the construction stage, and the output result has offset, so that the application of the method in cable force detection and long-term monitoring is limited. The magnetic flux method needs to measure the characteristics of the inhaul cable material in advance and place a small electromagnetic sensor in the inhaul cable, so that the inhaul cable material can be used for measuring the cable force of a bridge in the construction process. The accuracy of the test results of the vibration frequency method is very dependent on the experience of the tester and is affected by the length of the cable, the constraints at both ends, the bending stiffness and sagging of the cable, and other external factors. From the above analysis, in the prior art, when measuring the cable force of the cable (the external tension applied to the cable), the measuring instrument needs to be placed on the cable to measure the tension applied to the cable, so as to improve the measuring difficulty.
In order to solve the technical problems, the invention provides a three-dimensional point cloud-based inhaul cable force identification method, equipment and a storage medium, which solve the problem that the existing inhaul cable force measurement method improves the measurement difficulty. When the method is implemented, firstly, preprocessing is carried out on three-dimensional point cloud data of the inhaul cable to obtain two-dimensional data of the inhaul cable; then, according to the two-dimensional data of the inhaul cable, the horizontal span of the inhaul cable in the horizontal direction and the elevation difference of the inhaul cable in the vertical direction are obtained; and finally, obtaining the tension value of the inhaul cable according to the horizontal span, the elevation difference, the gravity of the inhaul cable and the two-dimensional data of the inhaul cable. The invention can reduce the measuring difficulty of measuring the tension of the inhaul cable.
For example, three-dimensional coordinates (a 1, b1, c 1) and three-dimensional coordinates (a 2, b2, c 2) of any two points on the inhaul cable are collected, the three-dimensional coordinates of the two points are converted into two-dimensional coordinates (a 11, b 11) and (a 22, b 22), then horizontal spans and elevation differences between the two points are calculated according to the two-dimensional coordinates of the two points, and finally the horizontal spans, the elevation differences, the gravity of the inhaul cable and the two-dimensional coordinates of the two points are substituted into a model formed by the pulling force and the coordinates of each point, so that the pulling force between the two points can be calculated.
Exemplary method
The guy cable force identification method based on the three-dimensional point cloud can be applied to terminal equipment, and the terminal equipment can be a terminal product with a calculation function, such as a computer and the like. In this embodiment, as shown in fig. 1, the method for identifying the cable force of the inhaul cable based on the three-dimensional point cloud specifically includes the following steps:
s100, preprocessing three-dimensional point cloud data of the inhaul cable to obtain two-dimensional data of the inhaul cable, wherein the three-dimensional point cloud data are used for representing three-dimensional coordinate information of each point on the inhaul cable.
And acquiring point cloud data of the inhaul cable by adopting a RIEGL_VZ-400i ground three-dimensional laser scanner of the middle-measurement Rayleigh and matched point cloud data processing software RISCAN-PRO to obtain three-dimensional point cloud data of the embodiment, wherein the three-dimensional point cloud data represents three-dimensional coordinates of all points on the inhaul cable.
The preprocessing in this embodiment is the normalization processing shown in fig. 2, where the normalization processing includes collection, registration, splicing, output, and the like of point clouds, the point cloud data after the normalization processing is exported to a ply format, and sparse outliers and obvious measurement noise in the point clouds are filtered by using a statistical filter in an open3D open source tool library of Python. And converting the three-dimensional point cloud data (the ply format) after the standardization processing into two-dimensional data.
In one embodiment, step S100 includes steps S101 to S105 as follows:
s101, determining the projection of one end part of the inhaul cable on the horizontal plane where the other end part is located, and marking the projection as a projection point.
As shown in fig. 3, the curve OA is a section of the cable, the point O is one end of the cable, the point a is the other end, and the horizontal plane where the end a is located is the lower bottom surface of the cube. The projection of the end O on the lower bottom surface of the cube is B.
S102, establishing a plane equation of the inhaul cable according to the coordinates of the two end parts and the coordinates of the projection points.
The three-dimensional coordinates (x O ,y O ,z O ) Three-dimensional coordinates of point a (x a ,y a ,z a ) Three-dimensional coordinates of point B (x b ,y b ,z b ) Substituting the parameters into the formula (1) to calculate the parameters A, B, C, D of the plane equation so as to establish the plane equation of the inhaul cable OA.
Ax+By+Cz+D＝0 (1)
And S103, projecting the three-dimensional point cloud data of the inhaul cable to a plane where the plane equation is located, and obtaining preselected two-dimensional data of the inhaul cable.
Projecting the three-dimensional point cloud to the plane by using setModelCoefficients method in the PCL open source tool library of python to obtain a two-dimensional data point set { x ] of the actually measured cable shape after dimension reduction j ，y j Will { x } j ，y j The pre-selected two-dimensional data of the cable is noted.
S104, constructing a fitting curve of the inhaul cable according to the preselected two-dimensional data.
The preselected two-dimensional data { x } is then obtained by the optimize. Leastq method in the scipy library in Python j ，y j Fitting a smooth curve.
S105, selecting the two-dimensional data on the fitting curve from the preselected two-dimensional data to obtain the final two-dimensional data of the inhaul cable.
For example, the preselected two-dimensional data has { x } 1 ,y 1 }、{x 2 ,y 2 }、{x 3 ,y 3 }、{x 4 ,y 4 }、{x 5 ,y 5 Of which only { x } 1 ,y 1 }、{x 3 ,y 3 }、{x 5 ,y 5 Located on the fitted curve, { x }, then 1 ,y 1 }、{x 3 ,y 3 }、{x 5 ,y 5 The coordinates of these three points are the final two-dimensional data.
And S200, obtaining the horizontal span of the inhaul cable in the horizontal direction and the elevation difference in the vertical direction according to the two-dimensional data of the inhaul cable.
The two-dimensional data of the cable may be the preselected two-dimensional data in step S103 or the final two-dimensional data in step S105. The horizontal span l between any two points on the inhaul cable is the difference between the horizontal coordinates of the two points, and the elevation difference h is the difference between the vertical coordinates of the two points.
S300, obtaining the tension value of the inhaul cable according to the horizontal span l, the elevation difference h, the gravity q (gravity on unit length) of the inhaul cable and the two-dimensional data of the inhaul cable.
The calculation of the tension value H is based on the formula (2), and the component force H of the external tension T on the two points on the inhaul cable in the x-axis direction can be calculated by combining the horizontal span l and the elevation difference H between any two points on the inhaul cable, the gravity q of the inhaul cable and the two-dimensional data of the two points with the formula (2).
Where x is the abscissa of a line segment formed by any two points on the cable (the abscissa of the line segment is the two
The difference between the abscissas of the points), y is the ordinate of a line segment formed by any two points on the cable (the ordinate of the line segment is the difference between the abscissas of the two points).
For example, taking fig. 4 as an example, if one of any two points on the cable is the cable end O and the other is P, x is the abscissa of the line segment OP and y is the ordinate of the line segment OP.
In one embodiment, step S300 includes steps S301 to S307 as follows:
s301, obtaining a first angle beta according to the ratio of the product of the gravity q of the inhaul cable and the horizontal span l to the constructed tension parameter H.
The force direction of the tension parameter H is parallel to the abscissa.
S302, determining the ratio of the elevation difference h to the horizontal span l, and recording the ratio as a first ratio h/l.
S303, determining the ratio of the product beta (h/l) of the first angle beta and the first ratio h/l to the hyperbolic sine function sinh (beta) of the first angle beta, and recording as a second ratio
S304, an anti-hyperbolic sine function according to the second ratio
And obtaining a second angle theta with the first angle beta.
S305, determining the ratio of the product beta x of the first angle beta and the abscissa of any two points on the inhaul cable to the horizontal span l, and marking the ratio as a third ratio
S306, a hyperbolic cosine function according to the second angle and the third ratio
The second angle θ, the ratio of the tension parameter H to the gravity q ∈>
And constructing a inhaul cable model related to the tension parameter by using the ordinate y of any two points on the inhaul cable:
s307, obtaining a tension value between any two points on the inhaul cable by solving the tension parameter in the inhaul cable model.
Substituting beta in the formula (3) into the formula (4) to obtain a deformation formula, substituting beta in the formula (3) and the deformation formula into the formula (5), wherein X and y are the abscissas and ordinates of a line segment formed by any two points on the inhaul cable (which can be calculated according to the acquired three-dimensional point cloud data), l and H are the abscissas and ordinates of the line segment, q is a constant, and therefore only unknown H is left, and the force H (the direction of force applied to the inhaul cable by the line segment between any two points on the inhaul cable along the X-axis direction) of the external force applied to the inhaul cable can be calculated according to the acquired three-dimensional point cloud data of any two points on the inhaul cable.
In one embodiment, after the external tension H applied to a certain section of the stay cable is calculated, the included angle alpha between the section of the stay cable and the X axis is combined x The resultant force T (the resultant force is along the tangential direction of the cable) of the cable can be calculated, and the Taylor formula is used for calculating alpha x And T is corrected. In this embodiment, calculating the resultant force T includes the following steps S401 to S408:
s401, determining the third ratio
Negative value of the inverse hyperbolic sine function of the difference from the second angle θ
Recorded as tangent value- & lt- & gt>
S402, according to the arctangent function of the tangent value
Obtaining the inclination angle alpha of the straight line formed by any two points on the inhaul cable relative to the horizontal direction x ：
tan -1 As an arctangent function, arctan may also be used to represent an arctangent function.
S403, establishing a regression model of two-dimensional data of any two points on the inhaul cable with respect to the tension H parameter in the horizontal direction.
y＝f(x，H)+ε (7)
(x, y) is the coordinates of a line segment formed between any two points on the cable, and f (x, H) is a nonlinear regression model, which means that the point set { x) j ，y j And inputting an initial value H0 into the model, wherein the difference between y and yi in the point set calculated according to the catenary equation in the formula (5) is represented by epsilon, and epsilon is the error of the regression model, namely the residual error generated by the measured point set on the catenary equation.
S404, inputting a tension set value corresponding to the tension parameter into the regression model.
S405, performing first-order Taylor expansion on the regression model input with the tension set value to obtain a first-order Taylor expansion.
S406, obtaining a final tension value of the inhaul cable in the horizontal direction according to the first-order Taylor expansion.
Initial value H of cable force input H according to experience or design (0) Equation (7) is set at H (0) Taylor expansion is carried out at the position, and only the 1 st order expansion is taken, namely
And then calculating the sum of squares of residual errors generated by the actual measurement point set on the catenary equation, and S (H):
substituting the formula (9) into the formula (8) to obtain any initial value H (0) Corresponding sum of squares of residuals S (H 0 )：
Wherein, the liquid crystal display device comprises a liquid crystal display device,
the optimal estimated value of the horizontal tension H of the inhaul cable is such that the sum of squares S (H 0 ) Minimizing. Deriving formula (10) from H and making it equal to 0 to obtain a sum of squares of residual errors S (H 0 ) An estimated value H of H reaching the minimum (1) I.e.
Will H (1) As an initial value H (0) Substituting the final estimated value H into the formula (12) again for iteration until convergence, and obtaining the final estimated value H'.
S407, correcting the inclination angle alpha according to the final tension value H x ′。
Substituting the formula (3) into the formula (6) to obtain the inclination angle alpha x Is a modified formula of (a):
substituting the final estimated value H' into equation (13) to obtain the corrected inclination angle alpha x ′：
Can calculate and obtain any position on the rope shapeTension T of pull cable of x x 。
S408, according to the inclination angle alpha 'after correction' x And obtaining a final tension value T' between any two points on the inhaul cable along the tangential direction of the inhaul cable.
Inclination angle alpha 'after correction' x Substituted into formula (15)
T＝H/cos(α x ) (15)
Wherein T is the tension value in the tangential direction of the inhaul cable before correction, and alpha 'is calculated' x Substituting formula (15) to obtain a final tension value T':
T′＝H/cos(α′ x ) (16)
in one embodiment, after the three-dimensional point cloud data is collected, as shown in fig. 5, a digital twin entity of the guy cable is built by using the three-dimensional point cloud data, and the specific process is as follows:
and outputting the Python filtered point cloud data into an Excel file, reading the point cloud data by using a Dynamo data.Import Excel method, and displaying the point cloud through display coordinate point nodes (Point. ByCoordinates) in a function library.
Using the Pointcloud Select Points By Local Sample method in node package Sastrogi provided by Dynamo authorities, points of several fitting curves are extracted in Active View as control points.
Three-dimensional curves were created by control points using the nurbs Curve. ByPoints method.
The Model element node picks up the baseline, identifies the wire, and shifts the wire up and down by a certain amount (cable radius) to create a number of curves.
And combining the curves into a group of line data through List.Create, and generating a guy cable entity model through solid.ByL-oft.
The method of the node package Springs (Springs.family. ByGetry) is utilized to endow the model with materials, select family categories, set attribute properties such as family names and the like. The node can automatically call a texture library and a family library in the Revit software.
The model is synchronously imported into the Revit and stored as a standard format, and the interpretation can be edited for the second time through an editing family command in the Revit software, and can also be imported into corresponding application software for use.
In summary, the invention firstly carries out dimension reduction pretreatment on three-dimensional point cloud data for representing positions of each point on the inhaul cable to obtain two-dimensional data of the positions of each point. And then calculating the horizontal span and the elevation difference between any two points according to the two-dimensional data of the positions of the points. And finally, calculating the external tension between any two points on the inhaul cable according to the horizontal span, the elevation difference, the two-dimensional data of the positions of each point and the gravity of the inhaul cable. According to the analysis, the external tension force received by each point on the inhaul cable is directly calculated through the three-dimensional point cloud data, and the three-dimensional point cloud data is acquired without an instrument arranged on the inhaul cable, so that the difficulty in measuring the tension force of the inhaul cable is reduced.
In addition, the invention uses the ground three-dimensional laser scanner to accurately scan and data standardized processing the stay cable, and uses python to extract geometric features and calculate cable force, thus realizing a non-invasive cable force measurement, being used as parallel supplement of the current cable force measurement method, reducing inaccuracy caused by single cable force measurement means, and providing reliable parameters for the current cable force calculation practical formulas by high-precision geometric data obtained by laser scanning, such as space sag, dip angle, cable length and the like of the stay cable.
Revit is used as building information management software, a large amount of structural information can be collected, the group libraries established by the existing technology for the stay cables of Revit are fewer, and most of the existing technology is a linear group library, so that the space state and the true linearity of the stay cables are not considered. According to the invention, point cloud data is imported by using dynamo visual programming technology, a curved surface solid model of the inhaul cable is established and exported to a family library in Revit, so that related personnel can conveniently establish the inhaul cable solid model in a real form and provide reference for later inhaul cable overhaul and maintenance.
Based on the above embodiment, the present invention also provides a terminal device, and a functional block diagram thereof may be shown in fig. 6. The terminal equipment comprises a processor, a memory, a network interface, a display screen and a temperature sensor which are connected through a system bus. Wherein the processor of the terminal device is adapted to provide computing and control capabilities. The memory of the terminal device comprises a nonvolatile storage medium and an internal memory. The non-volatile storage medium stores an operating system and a computer program. The internal memory provides an environment for the operation of the operating system and computer programs in the non-volatile storage media. The network interface of the terminal device is used for communicating with an external terminal through a network connection. The computer program, when executed by the processor, implements a three-dimensional point cloud-based guy cable force identification method. The display screen of the terminal equipment can be a liquid crystal display screen or an electronic ink display screen, and the temperature sensor of the terminal equipment is preset in the terminal equipment and is used for detecting the running temperature of the internal equipment.
It will be appreciated by those skilled in the art that the functional block diagram shown in fig. 6 is merely a block diagram of some of the structures associated with the present inventive arrangements and is not limiting of the terminal device to which the present inventive arrangements are applied, and that a particular terminal device may include more or less components than those shown, or may combine some of the components, or may have a different arrangement of components.
In one embodiment, a terminal device is provided, the terminal device includes a memory, a processor, and a three-dimensional point cloud-based cable force identification program stored in the memory and capable of running on the processor, where when the processor executes the three-dimensional point cloud-based cable force identification program, the following operation instructions are implemented:
preprocessing three-dimensional point cloud data of a guy cable to obtain two-dimensional data of the guy cable, wherein the three-dimensional point cloud data are used for representing three-dimensional coordinate information of each point on the guy cable;
according to the two-dimensional data of the inhaul cable, the horizontal span of the inhaul cable in the horizontal direction and the elevation difference of the inhaul cable in the vertical direction are obtained;
and obtaining the tension value of the inhaul cable according to the horizontal span, the elevation difference, the gravity of the inhaul cable and the two-dimensional data of the inhaul cable.
Those skilled in the art will appreciate that implementing all or part of the above described methods may be accomplished by way of a computer program stored on a non-transitory computer readable storage medium, which when executed, may comprise the steps of the embodiments of the methods described above. Any reference to memory, storage, database, or other medium used in embodiments provided herein may include non-volatile and/or volatile memory. The nonvolatile memory can include Read Only Memory (ROM), programmable ROM (PROM), electrically Programmable ROM (EPROM), electrically Erasable Programmable ROM (EEPROM), or flash memory. Volatile memory can include Random Access Memory (RAM) or external cache memory. By way of illustration and not limitation, RAM is available in a variety of forms such as Static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), double Data Rate SDRAM (DDRSDRAM), enhanced SDRAM (ESDRAM), synchronous Link DRAM (SLDRAM), memory bus direct RAM (RDRAM), direct memory bus dynamic RAM (DRDRAM), and memory bus dynamic RAM (RDRAM), among others.
Finally, it should be noted that: the above embodiments are only for illustrating the technical solution of the present invention, and are not limiting; although the invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical scheme described in the foregoing embodiments can be modified or some technical features thereof can be replaced by equivalents; such modifications and substitutions do not depart from the spirit and scope of the technical solutions of the embodiments of the present invention.
Claims (10)
1. The inhaul cable force identification method based on the three-dimensional point cloud is characterized by comprising the following steps of:
preprocessing three-dimensional point cloud data of a guy cable to obtain two-dimensional data of the guy cable, wherein the three-dimensional point cloud data are used for representing three-dimensional coordinate information of each point on the guy cable;
according to the two-dimensional data of the inhaul cable, the horizontal span of the inhaul cable in the horizontal direction and the elevation difference of the inhaul cable in the vertical direction are obtained;
and obtaining the tension value of the inhaul cable according to the horizontal span, the elevation difference, the gravity of the inhaul cable and the two-dimensional data of the inhaul cable.
2. The method for recognizing cable force based on three-dimensional point cloud as recited in claim 1, wherein preprocessing three-dimensional point cloud data of the cable to obtain two-dimensional data of the cable, the three-dimensional point cloud data being used for representing three-dimensional coordinate information of each point on the cable, comprises:
determining the projection of one end part of the inhaul cable on the horizontal plane where the other end part is positioned, and marking the projection as a projection point;
establishing a plane equation of the inhaul cable according to the coordinates of the two end parts and the coordinates of the projection points;
projecting the three-dimensional point cloud data of the inhaul cable to a plane in which the plane equation is located, so as to obtain preselected two-dimensional data of the inhaul cable;
constructing a fitting curve of the inhaul cable according to the preselected two-dimensional data;
and selecting the two-dimensional data positioned on the fitting curve from the preselected two-dimensional data to obtain the final two-dimensional data of the inhaul cable.
3. The method for identifying cable force of a cable based on three-dimensional point cloud as recited in claim 1, wherein the obtaining the horizontal span of the cable in the horizontal direction and the elevation difference in the vertical direction according to the two-dimensional data of the cable comprises:
determining two-dimensional data of each point on the inhaul cable in the two-dimensional data of the inhaul cable, wherein the two-dimensional data of each point is used for representing coordinates of each point in a two-dimensional coordinate system;
and determining the horizontal span and the elevation difference between any two points on the inhaul cable according to the two-dimensional data of each point on the inhaul cable.
4. The method for recognizing cable force of a cable based on a three-dimensional point cloud as recited in claim 1, wherein the gravity of the cable is the dead weight of the cable per unit length, and the obtaining the tension value of the cable according to the horizontal span, the elevation difference, the gravity of the cable and the two-dimensional data of the cable includes:
obtaining a first angle according to the ratio of the product of the gravity of the inhaul cable and the horizontal span to the constructed tension parameter;
determining a ratio of the elevation difference to the horizontal span, and recording the ratio as a first ratio;
determining the ratio of the product of the first angle and the first ratio to the hyperbolic sine function of the first angle, and recording the ratio as a second ratio;
obtaining a second angle according to the inverted hyperbolic sine function of the second ratio and the first angle;
constructing a cable model related to the tension parameter according to the second angle, the first angle, the horizontal span between any two points on the cable, the gravity of the cable and the coordinates of any two points on the cable;
and obtaining a tension value between any two points on the inhaul cable by solving the tension parameter in the inhaul cable model.
5. The method for recognizing cable force based on three-dimensional point cloud as recited in claim 4, wherein the tension parameter is a horizontal split tension parameter, and constructing a cable model with respect to the tension parameter based on the second angle, the first angle, the horizontal span between any two points on the cable, the gravity of the cable, and coordinates of any two points on the cable comprises:
determining the ratio of the product of the first angle and the abscissa of any two points on the inhaul cable to the horizontal span, and recording the ratio as a third ratio;
and constructing a cable model related to the tension parameter according to the hyperbolic cosine function of the second angle, the hyperbolic cosine function of the third ratio, the second angle, the ratio of the tension parameter to the gravity and the ordinate of any two points on the cable.
6. The method for identifying cable force based on three-dimensional point cloud as recited in claim 5, wherein the tension value is a tension value in a horizontal direction, and the method further comprises the steps of:
determining a negative value of an anti-hyperbolic sine function of the difference between the third ratio and the second angle, and recording the negative value as a tangent value;
obtaining the inclination angle of a straight line formed by any two points on the inhaul cable relative to the horizontal direction according to the arc tangent function of the tangent value;
and obtaining the tension value between any two points on the inhaul cable along the tangential direction of the inhaul cable according to the tension value in the horizontal direction and the inclination angle.
7. The method for identifying cable force of a cable based on three-dimensional point cloud as recited in claim 6, wherein the obtaining the tension value between any two points on the cable along the tangential direction of the cable according to the tension value in the horizontal direction and the inclination angle comprises:
establishing a regression model of two-dimensional data of any two points on the inhaul cable with respect to tension parameters in the horizontal direction;
inputting a tension set value corresponding to the tension parameter into the regression model;
performing first-order Taylor expansion on the regression model input with the tension set value to obtain a first-order Taylor expansion;
obtaining a final tension value of the inhaul cable in the horizontal direction according to the first-order Taylor expansion;
correcting the inclination angle according to the final tension value;
and obtaining a final tension value between any two points on the inhaul cable along the tangential direction of the inhaul cable according to the corrected inclination angle.
8. The three-dimensional point cloud-based guy cable force identification method of claim 2, further comprising:
taking a point corresponding to the final two-dimensional data of the inhaul cable as a control point;
creating a three-dimensional curve of the inhaul cable according to the control points;
performing offset in a set direction on the three-dimensional curve to obtain the three-dimensional curve after a plurality of offsets;
and constructing a BIM model of the inhaul cable according to the three-dimensional curves after the deviations.
9. A terminal device, characterized in that the terminal device comprises a memory, a processor and a three-dimensional point cloud based cable force identification program stored in the memory and operable on the processor, wherein the processor implements the steps of the three-dimensional point cloud based cable force identification method according to any one of claims 1-8 when executing the three-dimensional point cloud based cable force identification program.
10. A computer-readable storage medium, wherein a three-dimensional point cloud-based cable force identification program is stored on the computer-readable storage medium, and when the three-dimensional point cloud-based cable force identification program is executed by a processor, the steps of the three-dimensional point cloud-based cable force identification method according to any one of claims 1 to 8 are implemented.
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| CN112081285A (en) * | 2020-08-17 | 2020-12-15 | 北京市建筑工程研究院有限责任公司 | Method for determining length of prestressed stay cable of cable structure |
| CN113483932A (en) * | 2021-05-31 | 2021-10-08 | 周银 | System and method for testing accurate stay cable force based on cable shape measurement |
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- 2023-03-02 CN CN202310234836.7A patent/CN116363640A/en active Pending
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| CN112081285A (en) * | 2020-08-17 | 2020-12-15 | 北京市建筑工程研究院有限责任公司 | Method for determining length of prestressed stay cable of cable structure |
| CN113483932A (en) * | 2021-05-31 | 2021-10-08 | 周银 | System and method for testing accurate stay cable force based on cable shape measurement |
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