A method for testing the cable force of stay cables of cable-stayed bridges based on airborne millimeter-wave radar

Abstract

The present invention relates to the technical field of structural monitoring, and particularly to a method for testing the cable force of stay cables of a cable-stayed bridge based on an airborne millimeter-wave radar, including: Step S1, detecting the vibration response and the acceleration response, and recording the spatial position coordinates; Step S2, converting the vibration response into a response spectrum, converting the acceleration response into a displacement vibration spectrum, and calculating the vibration displacement spectrum; Step S3, determining the stay cable vibration spectrum of the stay cable; Step S4, judging whether the vibration condition of the stay cable is qualified according to the vibration amplitude in the stay cable vibration spectrum; Step S5, calculating the cable force of the stay cable; in the present invention, the data analysis module determines the vibration condition of the stay cable according to the difference between the response spectrum and the vibration displacement spectrum, eliminates the influence of the vibration of the unmanned aerial vehicle itself on the measured vibration response of the stay cable, improves the analysis accuracy of the vibration condition of the stay cable, and improves the calculation efficiency of the vibration response of the stay cable.

Description

Technical Field

[0001] The present invention relates to the technical field of structural monitoring, and particularly relates to a method for testing the cable force of stay cables of a cable-stayed bridge based on an airborne millimeter-wave radar. Background Technique

[0002] The stay cables of a cable-stayed bridge are important components of the cable-stayed bridge structure, undertaking the load transfer and support functions of the bridge. The cable force of a stay cable refers to the magnitude of the tensile force received by the stay cable. The following will introduce the cable force of the stay cables of a cable-stayed bridge according to the search results. The prior art uses a ground-based radar to collect the deformation data of the stay cables and analyzes the deformation data to determine the cable force of the stay cables, realizing the simultaneous monitoring of the cable forces of multiple stay cables. However, the data collection time of the ground-based radar is long, and the calculation efficiency of the cable force is low.

[0003] Chinese Patent Application No.: CN202210705941.X discloses a method for synchronously monitoring the cable force of stay cables of a cable-stayed bridge based on a ground-based radar. The invention proposes a method for synchronously monitoring the cable force of stay cables of a cable-stayed bridge based on a ground-based radar, including the following steps: Step S1, using a ground-based radar to synchronously collect the deformation data of multiple stay cables of a cable-stayed bridge, positioning and distinguishing the bridge stay cables through signal-to-noise ratio, distance, and angle data, obtaining the vibration response information of each stay cable, and converting the stay cable time history in the information; Step S2, preprocessing the stay cable data using variational mode decomposition (VMD) and band-pass filtering; Step S3, using the variational mode decomposition algorithm optimized by the salp swarm algorithm to decompose the deformation data preprocessed in Step S2 to obtain the modal vibration signals of each order; Step S4, determining the modal components, obtaining the instantaneous frequency through Hilbert transform, and estimating the cable force of each stay cable in combination with the frequency method; The invention can monitor the cable force borne by the stay cables of a cable-stayed bridge in a non-contact manner and can also monitor the cable forces of multiple stay cables simultaneously. It can be seen that the method for synchronously monitoring the cable force of stay cables of a cable-stayed bridge based on a ground-based radar has the following problems: Using a ground-based radar for data collection, the long data collection time leads to low calculation efficiency of the cable force. Summary of the Invention

[0004] Therefore, the present invention provides a method for testing the cable force of stay cables of a cable-stayed bridge based on an airborne millimeter-wave radar to overcome the problem in the prior art that using a ground-based radar for data collection results in low calculation efficiency of the cable force due to the long data collection time.

[0005] To achieve the above object, the present invention provides a method for testing the cable force of stay cables of a cable-stayed bridge based on an airborne millimeter-wave radar. The method includes:

[0006] Step S1, the unmanned aerial vehicle (UAV) flies to a designated position and hovers, and the airborne millimeter-wave radar aims at the stay cable area for reflection point confirmation, and the distance between the radar and the stay cable, as well as the number of stay cables and the specific stay cable numbers, are confirmed through the reflected wave.

[0007] Step S2: The UAV maintains a fixed-point hover and establishes monitoring signal connections for each stay cable.

[0008] Step S3: Use the on-board millimeter-wave radar to monitor the displacement vibration spectrum of each stay cable, and use a three-axis acceleration sensor to detect the radar acceleration response of the on-board millimeter-wave radar in each direction, so as to record the vibration response of the on-board millimeter-wave radar itself during the test according to the radar acceleration response.

[0009] Step S4: The data analysis module performs FFT transformation on the vibration response of the on-board millimeter-wave radar itself to obtain the acceleration spectrum, and calculates the displacement spectrum of the on-board millimeter-wave radar itself according to the acceleration spectrum.

[0010] Step S5: The data analysis module determines the stay cable vibration spectrum according to the difference between the stay cable displacement vibration spectrum and the displacement spectrum.

[0011] Step S6: The data analysis module determines whether the vibration condition of the stay cable is qualified according to the vibration amplitude in the stay cable vibration spectrum, and when it is determined that the vibration condition of the stay cable is unqualified, it makes a secondary determination on whether the vibration condition of the stay cable is qualified according to the theoretical value of the stay cable force, or determines the reason why the vibration condition of the stay cable is unqualified according to the vibration amplitude.

[0012] Step S7: When the data analysis module determines that the vibration condition of the stay cable is qualified, it calculates the stay cable force.

[0013] The preliminary determination method for the data analysis module to determine whether the vibration condition of the stay cable is qualified according to the vibration amplitude measured by the on-board millimeter-wave radar for a single stay cable, where:

[0014] The first preliminary determination method is that the data analysis module determines that the vibration condition of a single stay cable is qualified and calculates the stay cable force of this stay cable; the first preliminary determination method satisfies that the vibration amplitude is less than or equal to the first preset vibration amplitude in the data analysis module.

[0015] The second preliminary determination method is that the data analysis module preliminarily determines that the vibration condition of the stay cable is unqualified and makes a secondary determination on whether the vibration condition of the stay cable is qualified according to the inclination angle of the stay cable; the second preliminary determination method satisfies that the vibration amplitude is greater than the first preset vibration amplitude and less than or equal to the second preset vibration amplitude in the data analysis module.

[0016] The third preliminary determination method is that the data analysis module determines that the vibration condition of the stay cable is unqualified and determines the reason for its unqualified according to the vibration amplitude; the third preliminary determination method satisfies that the vibration amplitude is greater than the second preset vibration amplitude.

[0017] The data analysis module determines whether the vibration condition of the stay cable is qualified according to the inclination angle of the stay cable relative to the ground in the second determination method, where:

[0018] The first determination method is that the data analysis module determines that the vibration condition of the stay cable is qualified, and adjusts the first preset vibration amplitude to a corresponding value according to the inclination angle; the first determination method satisfies that the inclination angle is greater than or equal to the preset inclination angle in the data analysis module;

[0019] The second determination method is that the data analysis module determines that the vibration condition of the stay cable is unqualified, and determines the reason for its unqualified according to the vibration amplitude; the second determination method satisfies that the inclination angle is less than the preset inclination angle;

[0020] The data analysis module records the difference between the vibration amplitude and the second preset vibration amplitude as a secondary difference under the second preset condition, and determines the determination method for the reason that the vibration condition of the stay cable is unqualified according to the secondary difference, where:

[0021] The first reason determination method is that the data analysis module determines that the reason for the unqualified vibration condition of the stay cable is that the elimination processing of the vibration response to the airborne millimeter-wave radar is unqualified; the first reason determination method satisfies that the secondary difference is greater than or equal to the first preset secondary difference in the data analysis module;

[0022] The second reason determination method is that the data analysis module determines that the reason for the unqualified vibration condition of the stay cable is that the detection position is unqualified; the second reason determination method satisfies that the secondary difference is less than the first preset secondary difference and greater than or equal to the second preset secondary difference in the data analysis module;

[0023] The third reason determination method is that the data analysis module determines that the reason for the unqualified vibration condition of the stay cable is external environmental interference; the third reason determination method satisfies that the secondary difference is less than the second preset secondary difference;

[0024] The second preset condition is that the data analysis module determines the reason for the unqualified vibration condition of the stay cable according to the vibration amplitude.

[0025] Furthermore, when the data analysis module determines to adjust the first preset vibration amplitude to a corresponding value according to the inclination angle, it has several correction methods for the first preset vibration amplitude based on the inclination angle, and the correction amplitudes of each correction method for the first preset vibration amplitude are all different;

[0026] The data analysis module records the difference between the tilt angle and the preset tilt angle as the first-level difference in the first determination method, and determines the correction method for the first preset vibration amplitude according to the first-level difference, where:

[0027] The first correction method is that the data analysis module selects the first correction coefficient α1 to correct the first preset vibration amplitude D to the corresponding value, and sets the corrected first preset vibration amplitude D' = α1×D0, where D0 is the initial first preset vibration amplitude before correction; the first correction method satisfies that the first-level difference is less than or equal to the preset first-level difference in the data analysis module;

[0028] The second correction method is that the data analysis module selects the second correction coefficient α2 to correct the first preset vibration amplitude D to the corresponding value, and sets the corrected first preset vibration amplitude D' = α2×D0; the second correction method satisfies that the first-level difference is greater than the preset first-level difference.

[0029] Further, when the data analysis module completes the adjustment of the first preset vibration amplitude, it determines whether the vibration condition of the stay cable is qualified according to the corrected first preset vibration amplitude, and determines the reason for its unqualified according to the vibration amplitude when the vibration condition of the stay cable is determined to be unqualified.

[0030] Further, when the reason for the data analysis module to determine that the vibration condition of the stay cable is unqualified is that the elimination process of the vibration response of the airborne millimeter-wave radar is unqualified, it sets several adjustment methods for the gain of the signal amplifier of the vibration sensor according to the average value of the wind speed measured by the anemometer during the detection period, and the adjustment range of the gain for each adjustment method is different;

[0031] The data analysis module determines the adjustment method for the gain of the signal amplifier of the vibration sensor according to the average value of the wind speed measured by the anemometer during the detection period in the first cause determination method, where:

[0032] The first adjustment method is that the data analysis module selects the first adjustment coefficient β1 to adjust the gain M of the signal amplifier to the corresponding value, and sets the adjusted gain M' = β1×M0, where M0 is the initial gain before adjustment; the first adjustment method satisfies that the average value is less than or equal to the preset average value in the data analysis module;

[0033] The second adjustment method is that the data analysis module selects the second adjustment coefficient β2 to adjust the gain M of the signal amplifier to the corresponding value, and sets the adjusted gain M' = β2×M0; the second adjustment method satisfies that the average value is greater than the preset average value.

[0034] Further, when the data analysis module determines that the reason for the unqualified vibration condition of the stay cable is the unqualified detection position, it has several correction methods for the coordinates in the detection process of the airborne millimeter-wave radar based on the secondary difference, and the correction amplitudes of each correction method for the coordinates are different;

[0035] Under the second reason determination method, the data analysis module records the ratio of the secondary difference to the first preset secondary difference as the first-level ratio, and determines the coordinate correction method for the detection process of the airborne millimeter-wave radar according to the first-level ratio, where:

[0036] The first position correction method is that the data analysis module selects the first position correction coefficient γ1 to correct the coordinate D of the airborne millimeter-wave radar to the corresponding value, and sets the corrected coordinate D' = γ1 × D0, where D0 is the initial coordinate before correction; the first position correction method satisfies that the first-level ratio is less than or equal to the preset first-level ratio in the data analysis module;

[0037] The second position correction method is that the data analysis module selects the second position correction coefficient γ2 to correct the coordinate D of the airborne millimeter-wave radar to the corresponding value, and sets the corrected coordinate D' = γ2 × D0; the second position correction method satisfies that the first-level ratio is greater than the preset first-level ratio.

[0038] Further, when the airborne millimeter-wave radar determines that the reason for the unqualified vibration condition of the stay cable is external environmental interference, it continues to monitor the vibration condition of the stay cable, determines whether the vibration condition of the stay cable is qualified according to the average vibration frequency of the stay cable within the preset time, and issues an alarm signal when it determines that the vibration condition of the stay cable is unqualified;

[0039] Under the third reason determination method, the airborne millimeter-wave radar continues to monitor the vibration condition of the stay cable, and the evaluation method for determining whether the vibration condition of the stay cable is qualified according to the average vibration frequency of the stay cable within the preset time, where:

[0040] The first evaluation method is that the data analysis module determines that the vibration condition of the stay cable is qualified; the first evaluation method satisfies that the average vibration frequency is less than or equal to the preset average vibration frequency in the data analysis module;

[0041] The second evaluation method is that the data analysis module determines that the vibration condition of the stay cable is unqualified and issues an alarm signal; the second evaluation method satisfies that the average vibration frequency is greater than the preset average vibration frequency.

[0042] Further, the acceleration sensor is installed in a vibration isolation manner.

[0043] Compared with the prior art, the beneficial effects of the present invention are as follows. In the present invention, the data analysis module determines the vibration condition of the stay cable according to the difference between the response spectrum and the vibration displacement spectrum, eliminates the influence of the vibration of the UAV itself on the measured vibration response of the stay cable, improves the analysis accuracy of the vibration condition of the stay cable, and improves the calculation efficiency of the vibration response of the stay cable.

[0044] Further, in the present invention, the vibration condition of the stay cable is determined to be qualified according to the vibration amplitude of the stay cable. The inclination angle of the stay cable will affect the vibration amplitude of the stay cable. When the vibration amplitude of the stay cable is large, the data analysis module makes a secondary determination on whether the vibration condition of the stay cable is qualified according to the inclination angle of the stay cable relative to the ground, and increases the first preset vibration amplitude when the inclination angle is large, avoiding misjudgment caused by the influence of the inclination angle of the stay cable, improving the control accuracy of the vibration condition of the stay cable, and improving the calculation efficiency of the vibration parameters of the stay cable.

[0045] Further, in the present invention, the data analysis module determines the reason for the unqualified vibration condition of the stay cable according to the difference between the vibration amplitude of the stay cable and the second preset vibration amplitude, and determines that the elimination of the vibration response of the airborne millimeter-wave radar is unqualified when the difference is large, and adjusts the gain of the signal amplifier to the corresponding value, improving the signal output amplitude and the analysis accuracy of the vibration condition of the stay cable.

[0046] Further, in the present invention, when the secondary difference is between the first preset secondary difference and the second preset secondary difference, the data analysis module determines that the reason for the unqualified vibration condition of the stay cable is that the position of the stay cable detected by the UAV is unqualified. The middle part of the stay cable has a larger vibration amplitude relative to other positions. Therefore, this position is selected to represent the vibration amplitude of the stay cable, and the position in the UAV detection process is adjusted to the corresponding value according to the secondary difference, further improving the control accuracy of the detection process.

[0047] Further, in the present invention, the acceleration sensor is installed in a vibration isolation manner, reducing the extra noise signal and reducing the interference of environmental factors on the calculation of the vibration response of the stay cable. Description of the Drawings

[0048] Figure 1 It is a flowchart of a method for testing the cable force of a stay cable of a cable-stayed bridge based on an airborne millimeter-wave radar;

[0049] Figure 2 It is a flowchart for preliminarily determining whether the vibration condition of the stay cable is qualified;

[0050] Figure 3 It is a flowchart for secondary determination of whether the vibration condition of the stay cable is qualified;

[0051] Figure 4Flowchart for determining the reasons for unqualified vibration conditions of stay cables. Detailed implementation manners

[0052] To make the objectives and advantages of the present invention more clear and understandable, the present invention will be further described below in conjunction with embodiments; it should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0053] It should be noted that the data in this embodiment are all obtained through comprehensive analysis and evaluation of the historical data in the 6 months before this determination by the system described in the present invention and the corresponding historical determination results. The system described in the present invention determines the values of various preset parameter standards for this determination based on the comprehensive evaluation values of 42,383 retrieval results detected cumulatively in the previous three months before this detection. Those skilled in the art can understand that the determination method of the system described in the present invention for a single above-mentioned parameter can be to select the value with the highest proportion according to the data distribution as the preset standard parameter, use weighted summation to take the obtained value as the preset standard parameter, substitute each historical data into a specific formula and take the value obtained by using this formula as the preset standard parameter or other selection methods, as long as it satisfies that the system described in the present invention can clearly define different specific situations in a single determination process through the obtained values.

[0054] The preferred implementation manners of the present invention will be described below with reference to the accompanying drawings. Those skilled in the art should understand that these implementation manners are only used to explain the technical principles of the present invention and do not limit the protection scope of the present invention.

[0055] It should be noted that in the description of the present invention, the terms indicating directions or positional relationships such as "upper", "lower", "left", "right", "inner", "outer", etc. are based on the directions or positional relationships shown in the drawings. This is only for convenience of description and does not indicate or imply that the device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation of the present invention.

[0056] In addition, it should also be noted that in the description of the present invention, unless otherwise clearly specified and limited, the terms "installation", "connection", "connection" 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 directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two elements. For those skilled in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.

[0057] Please refer to Figure 1 as shown, which is a flowchart of a method for testing the cable force of stay cables of a cable-stayed bridge based on an airborne millimeter-wave radar.

[0058] Step S1: The drone flies to a specified position and hovers. The on-board millimeter-wave radar aims at the stay cable area to confirm the reflection points, and the distance between the radar and the stay cables, as well as the number of stay cables and the specific cable numbers, are confirmed through the reflected waves.

[0059] Step S2: The drone maintains a fixed-point hover and establishes monitoring signal connections for each stay cable.

[0060] Step S3: The on-board millimeter-wave radar is used to monitor the displacement vibration spectrum of each stay cable, and a three-axis acceleration sensor is used to detect the radar acceleration response of the on-board millimeter-wave radar in each direction, so as to record the vibration response of the on-board millimeter-wave radar itself during the test according to the radar acceleration response.

[0061] Step S4: The data analysis module performs FFT transformation on the vibration response of the on-board millimeter-wave radar itself to obtain the acceleration spectrum, and calculates the displacement spectrum of the on-board millimeter-wave radar itself according to the acceleration spectrum.

[0062] Step S5: The data analysis module determines the stay cable vibration spectrum according to the difference between the stay cable displacement vibration spectrum and the displacement spectrum.

[0063] Step S6: The data analysis module determines whether the vibration condition of the stay cable is qualified according to the vibration amplitude in the stay cable vibration spectrum, and when it is determined that the vibration condition of the stay cable is unqualified, it makes a secondary determination on whether the vibration condition of the stay cable is qualified according to the theoretical value of the stay cable force, or determines the reason for the unqualified vibration condition of the stay cable according to the vibration amplitude.

[0064] Step S7: When it is determined that the vibration condition of the stay cable is qualified, the data analysis module calculates the stay cable force.

[0065] In the present invention, the data analysis module determines the vibration condition of the stay cable according to the difference between the response spectrum and the vibration displacement spectrum, eliminates the influence of the vibration of the drone itself on the measured vibration response of the stay cable, improves the analysis accuracy of the vibration condition of the stay cable, and improves the calculation efficiency of the vibration response of the stay cable.

[0066] In the present invention, the drone flies to a specified position and hovers, and uses the on-board millimeter-wave radar to confirm the reflection points in the stay cable area. A reflected wave will be generated between each stay cable and the radar. The distance between the radar and the stay cable can be confirmed through the reflected wave. At the same time, the number of stay cables and the specific cable numbers can be confirmed by using the distance. The vibration response obtained by the on-board millimeter-wave radar using the reflected wave includes the stay cable vibration response and the vibration response of the drone itself.

[0067] Please refer to Figure 2 as shown, which is a flowchart for preliminarily determining whether the vibration condition of the stay cable is qualified.

[0068] In the embodiment of the present invention, the vibration frequency spectrum of the stay cable is the response frequency spectrum minus the vibration displacement frequency spectrum.

[0069] In the present invention, the vibration condition of the stay cable is determined according to the vibration amplitude of the stay cable. The inclination angle of the stay cable will affect the vibration amplitude of the stay cable. When the vibration amplitude of the stay cable is large, the data analysis module makes a secondary determination on whether the vibration condition of the stay cable is qualified according to the inclination angle of the stay cable relative to the ground, and increases the first preset vibration amplitude when the inclination angle is large, avoiding misjudgment caused by the influence of the inclination angle of the stay cable, improving the control accuracy of the vibration condition of the stay cable, and improving the calculation efficiency of the vibration parameters of the stay cable.

[0070] Specifically, the data analysis module makes a preliminary determination on whether the vibration condition of the stay cable is qualified according to the vibration amplitude of a single stay cable measured by the airborne millimeter-wave radar, where:

[0071] The first preliminary determination method is that the data analysis module determines that the vibration condition of a single stay cable is qualified and calculates the cable force of the stay cable; the first preliminary determination method satisfies that the vibration amplitude is less than or equal to the first preset vibration amplitude in the data analysis module;

[0072] The second preliminary determination method is that the data analysis module preliminarily determines that the vibration condition of the stay cable is unqualified and makes a secondary determination on whether the vibration condition of the stay cable is qualified according to the inclination angle of the stay cable; the second preliminary determination method satisfies that the vibration amplitude is greater than the first preset vibration amplitude and less than or equal to the second preset vibration amplitude in the data analysis module;

[0073] The third preliminary determination method is that the data analysis module determines that the vibration condition of the stay cable is unqualified and determines the reason for its unqualified according to the vibration amplitude; the third preliminary determination method satisfies that the vibration amplitude is greater than the second preset vibration amplitude.

[0074] In the embodiment of the present invention, the first preset vibration amplitude is 10 mm, the second preset vibration amplitude is 15 mm, and the first preset vibration amplitude is less than the second preset vibration amplitude.

[0075] Please refer to Figure 3 as shown, which is a flowchart for making a secondary determination on whether the vibration condition of the stay cable is qualified.

[0076] Specifically, the data analysis module makes a secondary determination on whether the vibration condition of the stay cable is qualified according to the inclination angle of the stay cable relative to the ground in the second determination method, where:

[0077] The first determination method is that the data analysis module determines that the vibration condition of the stay cable is qualified, and adjusts the first preset vibration amplitude to the corresponding value according to the inclination angle; the first determination method satisfies that the inclination angle is greater than or equal to the preset inclination angle in the data analysis module;

[0078] The second determination method is that the data analysis module determines that the vibration condition of the stay cable is unqualified, and determines the reason for its unqualified according to the vibration amplitude; the second determination method satisfies that the inclination angle is less than the preset inclination angle.

[0079] In the embodiment of the present invention, for a bridge with a main span of 150 - 300 meters, the preset inclination angle is 32 degrees.

[0080] Specifically, in the first determination method, the data analysis module records the difference between the inclination angle and the preset inclination angle as the first - level difference, and determines the correction method for the first preset vibration amplitude according to the first - level difference, where:

[0081] The first correction method is that the data analysis module selects the first correction coefficient α1 to correct the first preset vibration amplitude D to the corresponding value, and sets the corrected first preset vibration amplitude D' = α1×D0, where D0 is the initial first preset vibration amplitude before correction; the first correction method satisfies that the first - level difference is less than or equal to the preset first - level difference in the data analysis module;

[0082] The second correction method is that the data analysis module selects the second correction coefficient α2 to correct the first preset vibration amplitude D to the corresponding value, and sets the corrected first preset vibration amplitude D' = α2×D0; the second correction method satisfies that the first - level difference is greater than the preset first - level difference.

[0083] In the embodiment of the present invention, the first correction coefficient α1 is 1.15, the second correction coefficient is 1.2, and the preset first - level difference is 0.5 mm.

[0084] Specifically, the determination method for the data analysis module to determine whether the vibration condition of the stay cable is qualified according to the corrected first preset vibration amplitude under the first preset condition, where:

[0085] The first determination method is that the data analysis module determines that the vibration condition of the stay cable is qualified; the first determination method satisfies that the vibration amplitude of the stay cable is less than or equal to the corrected first preset vibration amplitude;

[0086] The second determination method is that the data analysis module determines that the vibration condition of the stay cable is unqualified, and determines the reason for its unqualified according to the vibration amplitude; the second determination method satisfies that the vibration amplitude of the stay cable is greater than the corrected first preset vibration amplitude;

[0087] The first preset condition is that the data analysis module completes the adjustment for the first preset vibration amplitude.

[0088] Please refer to Figure 4 as shown, which is a flowchart for determining the reasons for the unqualified vibration condition of the stay cable.

[0089] Specifically, under the second preset condition, the data analysis module records the difference between the vibration amplitude and the second preset vibration amplitude as the secondary difference, and determines the method for determining the reasons for the unqualified vibration condition of the stay cable according to the secondary difference, where:

[0090] The first reason determination method is that the data analysis module determines that the reason for the unqualified vibration condition of the stay cable is the unqualified elimination processing of the vibration response of the airborne millimeter-wave radar; the first reason determination method satisfies that the secondary difference is greater than or equal to the first preset secondary difference in the data analysis module;

[0091] The second reason determination method is that the data analysis module determines that the reason for the unqualified vibration condition of the stay cable is the unqualified detection position; the second reason determination method satisfies that the secondary difference is less than the first preset secondary difference and greater than or equal to the second preset secondary difference in the data analysis module;

[0092] The third reason determination method is that the data analysis module determines that the reason for the unqualified vibration condition of the stay cable is external environmental interference; the third reason determination method satisfies that the secondary difference is less than the second preset secondary difference;

[0093] The second preset condition is that the data analysis module determines the reasons for the unqualified vibration condition of the stay cable based on the vibration amplitude.

[0094] In the embodiment of the present invention, the first preset secondary difference is 0.8 mm, and the second preset secondary difference is 0.5 mm.

[0095] In the present invention, the data analysis module determines the reasons for the unqualified vibration condition of the stay cable according to the difference between the vibration amplitude of the stay cable and the second preset vibration amplitude, and determines that the elimination of the vibration response of the airborne millimeter-wave radar is unqualified when the difference is large, and adjusts the gain of the signal amplifier to the corresponding value, improving the signal output amplitude and the analysis accuracy of the vibration condition of the stay cable.

[0096] Specifically, under the first reason determination method, the data analysis module determines the adjustment method for the gain of the signal amplifier of the vibration sensor according to the average value of the wind speed measured by the anemometer during the detection time period, where:

[0097] The first adjustment method is that the data analysis module selects a first adjustment coefficient β1 to adjust the gain M of the signal amplifier to a corresponding value, and sets the adjusted gain M' = β1 × M0, where M0 is the initial gain before adjustment; the first adjustment method satisfies that the average value is less than or equal to the preset average value in the data analysis module;

[0098] The second adjustment method is that the data analysis module selects a second adjustment coefficient β2 to adjust the gain M of the signal amplifier to a corresponding value, and sets the adjusted gain M' = β2 × M0; the second adjustment method satisfies that the average value is greater than the preset average value.

[0099] In the present invention, the first adjustment coefficient is 1.23, the second adjustment coefficient is 1.32, the detection time period is 4h, and the preset average value is 8m / s.

[0100] Specifically, in the second cause determination method, the data analysis module records the ratio of the secondary difference to the first preset secondary difference as a primary ratio, and determines the coordinate correction method during the detection process of the airborne millimeter-wave radar according to the primary ratio, where:

[0101] The first position correction method is that the data analysis module selects a first position correction coefficient γ1 to correct the coordinate D of the airborne millimeter-wave radar to a corresponding value, and sets the corrected coordinate D' = γ1 × D0, where D0 is the initial coordinate before correction; the first position correction method satisfies that the primary ratio is less than or equal to the preset primary ratio in the data analysis module;

[0102] The second position correction method is that the data analysis module selects a second position correction coefficient γ2 to correct the coordinate D of the airborne millimeter-wave radar to a corresponding value, and sets the corrected coordinate D' = γ2 × D0; the second position correction method satisfies that the primary ratio is greater than the preset primary ratio.

[0103] In the embodiment of the present invention, the first position correction coefficient is 0.85, the second position correction coefficient is 0.78, and the preset primary ratio is 0.85.

[0104] In the present invention, when the secondary difference of the data analysis module is between the first preset secondary difference and the second preset secondary difference, it is determined that the reason for the unqualified vibration condition of the stay cable is that the position of the stay cable detected by the unmanned aerial vehicle is unqualified. The middle part of the stay cable has a larger vibration amplitude relative to other positions. Therefore, this position is selected to represent the vibration amplitude of the stay cable, and the position during the detection process of the unmanned aerial vehicle is adjusted to a corresponding value according to the secondary difference, further improving the control accuracy of the detection process.

[0105] Specifically, the airborne millimeter-wave radar continues to monitor the vibration condition of the stay cable under the third cause determination method, and determines whether the vibration condition of the stay cable is qualified according to the average vibration frequency of the stay cable within a preset time. Specifically:

[0106] The first evaluation method is that the data analysis module determines that the vibration condition of the stay cable is qualified; the first evaluation method satisfies that the average vibration frequency is less than or equal to the preset average vibration frequency in the data analysis module;

[0107] The second evaluation method is that the data analysis module determines that the vibration condition of the stay cable is unqualified and issues an alarm signal; the second evaluation method satisfies that the average vibration frequency is greater than the preset average vibration frequency.

[0108] In the embodiment of the present invention, the preset vibration frequency is 10 Hz.

[0109] Specifically, the acceleration sensor is installed in a vibration isolation manner.

[0110] In the present invention, the acceleration sensor is installed in a vibration isolation manner, reducing extra noise signals and reducing the interference of environmental factors on the calculation of the vibration response of the stay cable.

[0111] So far, the technical solution of the present invention has been described in conjunction with the preferred embodiments shown in the drawings. However, it is easy for those skilled in the art to understand that the protection scope of the present invention is obviously not limited to these specific embodiments. Without departing from the principle of the present invention, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will fall within the protection scope of the present invention.

[0112] The above are only the preferred embodiments of the present invention and are not used to limit the present invention; for those skilled in the art, the present invention can have various changes and modifications. Any modification, equivalent substitution, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for testing the cable force of a cable-stayed bridge based on airborne millimeter-wave radar, characterized in that: include: Step S1, the UAV flies to a designated position and hovers, and the airborne millimeter wave radar is aimed at the inclined cable area to confirm the reflection point, and the distance between the radar and the inclined cable, as well as the number of inclined cables and specific cable numbers are confirmed through the reflected wave; Step S2: The UAV maintains a fixed-point hover and establishes a monitoring signal connection for each stay cable; Step S3, using the airborne millimeter-wave radar to monitor the cable displacement vibration spectrum of each cable, using a three-axis acceleration sensor to detect the radar acceleration response of the airborne millimeter-wave radar itself in each direction, so as to record the vibration response of the airborne millimeter-wave radar itself during the test according to the radar acceleration response; Step S4: the data analysis module performs FFT transformation on the vibration response of the airborne millimeter-wave radar itself to obtain an acceleration spectrum, and calculates the displacement spectrum of the airborne millimeter-wave radar itself according to the acceleration spectrum; Step S5: the data analysis module determines the vibration spectrum of the inclined cable according to the difference between the displacement vibration spectrum of the inclined cable and the displacement spectrum; Step S6: The data analysis module determines whether the vibration condition of the cable is qualified according to the vibration amplitude in the vibration spectrum of the cable, and performs a secondary determination on whether the vibration condition of the cable is qualified according to the cable force theoretical value of the cable when the vibration condition of the cable is determined to be unqualified, or determines the reason why the vibration condition of the cable is unqualified according to the vibration amplitude: Step S7, the data analysis module calculates the cable force of the inclined cable when determining that the vibration condition of the inclined cable is qualified; The data analysis module determines whether the vibration condition of the cable is qualified according to the vibration amplitude of the single cable measured by the airborne millimeter wave radar, wherein: The first preliminary determination method is that the data analysis module determines that the vibration condition of a single cable is qualified and calculates the cable force of the cable; the first preliminary determination method satisfies that the vibration amplitude is less than or equal to the first preset vibration amplitude in the data analysis module; The second preliminary determination method is that the data analysis module preliminarily determines that the vibration condition of the inclined cable is unqualified, and performs a secondary determination on whether the vibration condition of the inclined cable is qualified according to the inclination angle of the inclined cable; the second preliminary determination method satisfies that the vibration amplitude is greater than the first preset vibration amplitude and is less than or equal to the second preset vibration amplitude in the data analysis module; The third preliminary determination method is that the data analysis module determines that the vibration condition of the cable is unqualified, and determines the reason for the unqualified condition according to the vibration amplitude; the third preliminary determination method satisfies that the vibration amplitude is greater than the second preset vibration amplitude; The data analysis module determines whether the vibration condition of the cable is qualified according to the inclination angle of the cable relative to the ground under the second determination mode, wherein: The first determination method is that the data analysis module determines that the vibration condition of the inclined cable is qualified, and adjusts the first preset vibration amplitude to a corresponding value according to the inclination angle; the first determination method satisfies that the inclination angle is greater than or equal to the preset inclination angle in the data analysis module; The second determination method is that the data analysis module determines that the vibration condition of the inclined cable is unqualified, and determines the reason for the unqualified condition according to the vibration amplitude; the second determination method satisfies that the inclination angle is less than the preset inclination angle; The data analysis module records the difference between the vibration amplitude and the second preset vibration amplitude under the second preset condition as a secondary difference, and determines a method for determining the cause of the unqualified vibration condition of the inclined cable according to the secondary difference, wherein: The first cause determination method is that the data analysis module determines that the reason why the vibration condition of the inclined cable is unqualified is that the elimination process of the vibration response of the airborne millimeter-wave radar is unqualified; the first cause determination method satisfies that the secondary difference is greater than or equal to the first preset secondary difference in the data analysis module; The second cause determination method is that the data analysis module determines that the reason why the vibration condition of the inclined cable is unqualified is that the detection position is unqualified; the second cause determination method satisfies that the secondary difference is less than the first preset secondary difference and is greater than or equal to the second preset secondary difference in the data analysis module; The third cause determination method is that the data analysis module determines that the reason why the vibration condition of the inclined cable is unqualified is external environmental interference; the third cause determination method satisfies that the secondary difference is less than the second preset secondary difference; The second preset condition is the reason why the data analysis module determines that the vibration condition of the inclined cable is unqualified according to the vibration amplitude.

2. The method for testing the cable force of a cable-stayed bridge based on airborne millimeter-wave radar according to claim 1 is characterized in that: When the data analysis module determines to adjust the first preset vibration amplitude to a corresponding value according to the tilt angle, a plurality of correction methods for the first preset vibration amplitude are provided based on the tilt angle, and the correction amplitudes of the first preset vibration amplitude in each correction method are different; The data analysis module records the difference between the tilt angle and the preset tilt angle as a primary difference under the first determination mode, and determines a correction mode for the first preset vibration amplitude according to the primary difference, wherein: The first correction method is that the data analysis module selects the first correction coefficient α1 to correct the first preset vibration amplitude D to a corresponding value, and sets the corrected first preset vibration amplitude D'=α1×D0, where D0 is the initial first preset vibration amplitude before correction; the first correction method satisfies that the first-level difference is less than or equal to the preset first-level difference in the data analysis module; The second correction method is that the data analysis module selects the second correction coefficient α2 to correct the first preset vibration amplitude D to a corresponding value, and sets the corrected first preset vibration amplitude D'=α2×D0; the second correction method satisfies that the first-level difference is greater than the preset first-level difference.

3. The method for testing the cable force of a cable-stayed bridge based on airborne millimeter-wave radar according to claim 1 is characterized in that: When the data analysis module completes the adjustment for the first preset vibration amplitude, it determines whether the vibration condition of the inclined cable is qualified according to the corrected first preset vibration amplitude, and when it is determined that the vibration condition of the inclined cable is unqualified, it determines the reason for its unqualified according to the vibration amplitude.

4. The method for testing the cable force of a cable-stayed bridge based on airborne millimeter-wave radar according to claim 1 is characterized in that: When the data analysis module determines that the reason why the vibration condition of the inclined cable is unqualified is that the elimination process of the vibration response of the airborne millimeter-wave radar is unqualified, a plurality of adjustment modes for the gain of the signal amplifier of the vibration sensor are provided according to the average value of the wind speed within the detection time period measured by the anemometer, and the adjustment range of the gain in each adjustment mode is different; The data analysis module determines the adjustment method of the gain of the signal amplifier for the vibration sensor according to the average value of the wind speed within the detection time period measured by the anemometer in the first cause determination method, wherein: The first adjustment method is that the data analysis module selects the first adjustment coefficient β1 to adjust the gain M of the signal amplifier to a corresponding value, and sets the adjusted gain M'=β1×M0, where M0 is the initial gain before adjustment; the first adjustment method satisfies that the average value is less than or equal to the preset average value in the data analysis module; The second adjustment method is that the data analysis module selects the second adjustment coefficient β2 to adjust the gain M of the signal amplifier to a corresponding value, and sets the adjusted gain M'=β2×M0; the second adjustment method satisfies that the average value is greater than the preset average value.

5. The method for testing the cable force of a cable-stayed bridge based on airborne millimeter-wave radar according to claim 4 is characterized in that: When the data analysis module determines that the reason why the vibration condition of the inclined cable is unqualified is that the detection position is unqualified, a plurality of correction methods for the coordinates in the detection process of the airborne millimeter-wave radar are provided based on the secondary difference, and the correction amplitude of the coordinates in each correction method is different; The data analysis module records the ratio of the secondary difference to the first preset secondary difference as a primary ratio under the second cause determination mode, and determines the coordinate correction mode for the airborne millimeter wave radar detection process according to the primary ratio, wherein: The first position correction method is that the data analysis module selects the first position correction coefficient γ1 to correct the coordinate D of the airborne millimeter-wave radar to the corresponding value, and sets the corrected coordinate D'=γ1×D0, where D0 is the initial coordinate before correction; the first position correction method satisfies that the first-level ratio is less than or equal to the preset first-level ratio in the data analysis module; The second position correction method is that the data analysis module selects the second position correction coefficient γ2 to correct the coordinate D of the airborne millimeter-wave radar to the corresponding value, and sets the corrected coordinate D'=γ2×D0; the second position correction method satisfies that the first-level ratio is greater than the preset first-level ratio.

6. The method for testing the cable force of a cable-stayed bridge based on airborne millimeter-wave radar according to claim 5 is characterized in that: When the airborne millimeter-wave radar determines that the vibration condition of the inclined cable is unqualified due to external environmental interference, the airborne millimeter-wave radar continues to monitor the vibration condition of the inclined cable, determines whether the vibration condition of the inclined cable is qualified according to the average vibration frequency of the inclined cable within a preset time, and issues an alarm signal when the vibration condition of the inclined cable is determined to be unqualified; The airborne millimeter-wave radar continues to monitor the vibration of the cable under the third cause determination mode, and determines whether the vibration of the cable is qualified according to the average vibration frequency of the cable within a preset time, wherein: The first evaluation method is that the data analysis module determines that the vibration condition of the cable is qualified; the first evaluation method satisfies that the average vibration frequency is less than or equal to the preset average vibration frequency in the data analysis module; The second evaluation method is that the data analysis module determines that the vibration condition of the inclined cable is unqualified and issues an alarm signal; the second evaluation method satisfies that the average vibration frequency is greater than the preset average vibration frequency.

7. The method for testing the cable force of a cable-stayed bridge based on airborne millimeter-wave radar according to claim 6 is characterized in that: The acceleration sensor is installed in a vibration isolation manner.

Images