Bridge catwalk construction safety monitoring and control system and method based on GNSS data

Abstract

The application provides a bridge catwalk construction safety monitoring and control system and method based on GNSS data. It relates to the technical field of bridge construction safety monitoring and intelligent control. The system comprises a GNSS data acquisition module, a data processing center, a threshold setting module, a warning control module and an execution control module. The coordinates of the catwalk monitoring points and the puller are collected to reconstruct the catwalk catenary equation and calculate the safety distance between the puller and the supporting roller. The safety threshold is determined by combining theoretical calculation, historical data and working condition parameters. The safety distance and the threshold are compared, and graded warning and control instructions are output when the distance is insufficient. The execution control module adjusts the winch operation and the traction system parameters accordingly, so that the safety distance is restored to the safety range, and real-time monitoring and automatic adjustment of the construction process are realized.

Description

Technical Field

[0001] This application relates to the field of bridge construction safety monitoring and intelligent control technology, and in particular to a bridge catwalk construction safety monitoring and control system and method based on GNSS data. Background Technology

[0002] Currently, with the continuous expansion of the construction scale of long-span suspension bridges, the requirements for safety control during bridge construction are becoming increasingly stringent. Catwalks, as crucial temporary structures for worker access and material transportation, directly impact overall construction safety through their spatial alignment and operational status. In existing technologies, catwalks are typically designed based on catenary theory, with their geometry calculated and controlled by considering factors such as cable weight, material elastic modulus, and cross-sectional parameters. During construction, to obtain the actual spatial location and operational status of the catwalk, data is typically collected from key nodes using methods such as manual measurement, total station observation, or periodic testing. Experience is also used to monitor the operational positions of construction equipment such as traction devices and rollers, thereby ensuring the orderly progress of construction to a certain extent. Furthermore, regarding the spatial relationships between equipment, on-site engineers often estimate safe distances based on design specifications or construction experience, supplemented by manual observation or simple measurements to achieve basic safety control.

[0003] However, the existing technologies mentioned above generally rely on manual measurement and experience-based judgment in practical applications, resulting in insufficient real-time data acquisition and difficulty in reflecting the instantaneous changes in the status of catwalks and related equipment during dynamic construction. Simultaneously, traditional measurement methods are easily affected by factors such as line-of-sight and environmental interference in complex terrain environments, limiting measurement accuracy and thus affecting the reliability of spatial location determination. Furthermore, safety distances are mostly set using empirical estimations or fixed standards, lacking a dynamic adjustment mechanism that incorporates real-time changes in operating conditions, making it difficult to accurately reflect the true safety boundaries under different construction conditions. In addition, existing monitoring methods lack unified data processing and automatic response capabilities, making it difficult to promptly warn of potential risks and take effective control measures, thereby increasing the risk of equipment interference and safety accidents during construction, affecting overall construction safety and operational efficiency. Summary of the Invention

[0004] This application addresses the problems of existing bridge catwalk construction processes that rely on manual measurement and experience-based judgment, resulting in poor real-time performance, insufficient accuracy, and a lack of automatic early warning and control mechanisms for safe distances. It provides a bridge catwalk construction safety monitoring and control system and method based on GNSS data. This system can accurately calculate and dynamically determine the safe distance between the catwalk, the puller, and the roller based on real-time GNSS positioning data, and achieve automatic control, thereby improving construction safety and automation levels.

[0005] To achieve the above objectives, this application provides the following technical solution: In the first aspect, this application provides a bridge catwalk construction safety monitoring and control system based on GNSS data, including a GNSS data acquisition module, a data processing center, a threshold setting module, an early warning control module, and an execution control module; The GNSS data acquisition module is used to acquire the coordinates of multiple monitoring points deployed on the catwalk and the real-time coordinates deployed on the puller, and transmit the acquired coordinates of multiple monitoring points deployed on the catwalk and the real-time coordinates deployed on the puller to the data processing center. The data processing center is used to reconstruct the catenary equation based on the coordinates of the multiple monitoring points, and to calculate the safe distance between the catenary and the puller, as well as the safe distance between the idler roller and the puller, based on the catenary equation and the real-time coordinates of the puller. The threshold setting module is used to determine the preset threshold corresponding to the safety distance; The early warning control module is used to compare the safety distance with the preset threshold, and output an early warning signal and control command when the safety distance is less than the preset threshold; The execution control module is used to adjust the operating status of the winch and the parameters of the traction system according to the control command, so that the safety distance is increased to not less than the preset threshold.

[0006] Optionally, the data processing center includes a catenary equation calculation submodule, which is used to perform moving median filtering preprocessing on the coordinates of the multiple monitoring points, and after correcting the preprocessed coordinates by multi-base station joint RTK calculation, solve the catenary equation based on the fourth-order Runge-Kutta method and Newton's iteration method.

[0007] Optionally, the GNSS data acquisition module uses a multi-GNSS system integrated processing method to obtain the real-time coordinates of the puller. The multi-GNSS system integrated processing method includes at least two of GPS, BeiDou and GLONASS, and performs Kalman filtering on the real-time coordinates of the puller.

[0008] Optionally, the calculation of the safety distance includes: calculating the safety distance between the catwalk and the puller using the minimum distance based on the curve corresponding to the catwalk catenary equation, and calculating the safety distance between the idler roller and the puller using three-dimensional Euclidean distance.

[0009] Optionally, the basic threshold is determined by theoretical calculation, empirical statistics, and dynamic adjustment.

[0010] Optionally, the theoretical calculation method determines the foundation threshold based on the safety factor and component geometry, the empirical statistical method verifies the foundation threshold using the 3σ principle based on historical construction spacing data, and the dynamic adjustment method corrects the foundation threshold based on at least one working condition parameter among crosswind speed, catwalk load, and puller speed.

[0011] Optionally, the early warning control module adopts a three-level early warning mechanism. The first early warning level corresponds to the safety distance being (1.5~1.2) times the preset threshold, the second early warning level corresponds to the safety distance being (1.2~1.0) times the preset threshold, and the third early warning level corresponds to the safety distance being less than the preset threshold.

[0012] Optionally, the first warning level corresponds to a visual alarm, the second warning level corresponds to an audible and visual alarm and outputs a deceleration command, and the third warning level corresponds to an emergency braking command.

[0013] Optionally, after receiving the control command, the execution control module adjusts the operating speed of the winch proportionally according to the three-level early warning mechanism, and controls the winch to stop running and activate the braking system at the third early warning level.

[0014] Optionally, the execution control module is further configured to calculate the deviation based on the safety distance and the preset threshold, then calculate the puller direction control amount based on the deviation, and generate an avoidance path control command based on the puller direction control amount.

[0015] Optionally, the execution control module is also used to automatically increase the traction tension when the safety distance is less than the preset threshold, and control the idler to enter the braking state and / or adjust the idler angle.

[0016] Optionally, the system further includes a multi-device collaborative control module, which coordinates the control commands of the catwalk, idler rollers, and pullers, and outputs them according to the priority relationship of safety over efficiency and efficiency over accuracy.

[0017] Optionally, the multi-device collaborative control module is also used to compensate for communication delays in order to adjust control parameters in advance based on the prediction results; wherein, the communication delay includes the data transmission delay from the GNSS data acquisition module to the data processing center, the data processing delay of the data processing center, and the response delay from the control command to the execution control module; the prediction results are the spatial coordinates or safety distances of the puller or catwalk at future times calculated based on historical motion data.

[0018] Secondly, this application provides a method for safety monitoring and control of bridge catwalk construction based on GNSS data, comprising the following steps: S1 collects the coordinates of multiple monitoring points deployed on the catwalk and the real-time coordinates of the pullers, and sends the collected data to the data processing center. S2, Reconstruct the catenary equation based on the coordinates of the multiple monitoring points, and calculate the safe distance between the catenary and the puller and the safe distance between the idler roller and the puller based on the catenary equation and the real-time coordinates of the puller. S3, determine the preset threshold corresponding to the safety distance based on theoretical calculation results, historical construction data and construction condition parameters; S4, compare the safety distance with the preset threshold, and output a warning signal and control command when the safety distance is less than the preset threshold; S5, adjust the winch operating status and traction system parameters according to the control command so that the safety distance is increased to not less than the preset threshold.

[0019] Optionally, in step S2, the reconstruction of the catenary equation includes: performing moving median filtering preprocessing on the coordinates of the multiple monitoring points, and after correcting the preprocessed coordinates by multi-base station joint RTK calculation, solving the catenary equation based on the fourth-order Runge-Kutta method and Newton's iteration method.

[0020] Optionally, in step S1, the real-time coordinates of the puller are obtained through a multi-GNSS system integration processing method, which includes at least two of GPS, BeiDou and GLONASS, and the real-time coordinates of the puller are processed by Kalman filtering.

[0021] Optionally, in step S2, the safety distance between the catwalk and the puller is calculated using the minimum distance based on the curve corresponding to the catwalk catenary equation, and the safety distance between the idler roller and the puller is calculated using three-dimensional Euclidean distance.

[0022] Optionally, in step S3, the basic threshold is determined by theoretical calculation, empirical statistics, and dynamic adjustment.

[0023] Optionally, the theoretical calculation method determines the foundation threshold based on the safety factor and component geometry, the empirical statistical method verifies the foundation threshold using the 3σ principle based on historical construction spacing data, and the dynamic adjustment method corrects the foundation threshold based on at least one working condition parameter among crosswind speed, catwalk load, and puller speed.

[0024] Optionally, a three-level early warning mechanism is adopted in step S4. The first early warning level corresponds to the safety distance being (1.5~1.2) times the preset threshold, the second early warning level corresponds to the safety distance being (1.2~1.0) times the preset threshold, and the third early warning level corresponds to the safety distance being less than the preset threshold.

[0025] Optionally, the first warning level corresponds to a visual alarm, the second warning level corresponds to an audible and visual alarm and outputs a speed reduction command, and the third warning level corresponds to an emergency braking command.

[0026] Optionally, in step S5, the operating speed of the winch is proportionally adjusted according to the three-level early warning mechanism, and the winch is stopped and the braking system is activated at the third early warning level.

[0027] Optionally, step S5 further includes calculating the deviation based on the safety distance and the preset threshold, calculating the puller direction control amount based on the deviation, and generating an avoidance path control command based on the puller direction control amount.

[0028] Optionally, step S5 further includes automatically increasing the traction tension when the safety distance is less than the preset threshold, and controlling the idler roller to enter the braking state and / or adjusting the idler roller angle.

[0029] Optionally, it also includes multi-device coordinated control of the catwalk, idler rollers and pullers, and outputs control parameters according to the priority relationship of safety over efficiency and efficiency over accuracy, while compensating for communication delay.

[0030] Compared with the prior art, this application has at least the following beneficial effects: This application introduces multi-source GNSS high-precision positioning technology to achieve real-time centimeter-level positioning of catwalks, pullers, and idlers, which significantly improves the real-time performance and accuracy of data acquisition compared to traditional manual measurement methods. By constructing the catwalk catenary equation based on GNSS data, the spatial morphology of the catwalk can be updated in real time, thereby significantly improving the accuracy and reliability of safety distance calculation.

[0031] The spacing calculation mechanism proposed in this application, which combines the minimum distance calculation method based on the catenary equation with the three-dimensional Euclidean distance calculation method, makes the assessment of the safe distance between different components more scientific and reasonable, and effectively avoids the error risk caused by relying on experience judgment.

[0032] This application innovatively adopts a multi-source threshold setting method that combines theoretical calculation, empirical statistics and dynamic adjustment, so that the safety threshold can be adjusted in real time according to the construction environment (such as crosswind, load and operating speed), which improves the system's adaptability to complex working conditions and significantly reduces the false alarm rate and false alarm rate.

[0033] By constructing a three-level early warning mechanism and a graded control strategy, an automated closed-loop control process from risk identification to control execution is realized. This not only provides timely warnings before danger occurs, but also automatically adjusts the winch speed, traction tension, and equipment operating status, thereby effectively preventing safety accidents.

[0034] Furthermore, this application achieves coordinated control between the catwalk, idler rollers, and pullers through a multi-device collaborative control mechanism, and further improves the overall response speed and control stability of the system through communication delay compensation and priority scheduling strategy (safety first), thereby ensuring construction safety while taking into account construction efficiency.

[0035] In summary, this application enables intelligent safety monitoring and automatic control of the entire construction process of bridge catwalks, significantly improving construction safety, real-time performance, and intelligence. Attached Figure Description

[0036] Figure 1 This application provides a diagram of a bridge catwalk construction safety monitoring and control system based on GNSS data; Figure 2 This application provides a flowchart of a method for monitoring and controlling the construction safety of bridge catwalks based on GNSS data; Figure 3 A schematic diagram of a bridge catwalk construction safety monitoring and control example (single tower) based on GNSS data provided in this application; Figure 4 A schematic diagram illustrating a construction safety monitoring and control example (double tower) of a bridge catwalk based on GNSS data, provided for this application.

[0037] Among them, 1. First anchorage; 2. Traction cable; 3. Main cable; 4. Catwalk load-bearing cable; 5. Second anchorage; 100. Bridge catwalk construction safety monitoring and control system; 110. GNSS data acquisition module; 120. Data processing center; 130. Threshold setting module; 140. Early warning control module; 150. Execution control module; 160. Multi-device collaborative control module. Detailed Implementation

[0038] The embodiments of this application are described in detail below. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this application, and should not be construed as limiting this application. The step numbers in the following embodiments are set only for ease of explanation, and there is no limitation on the order between the steps. The execution order of each step in the embodiments can be adaptively adjusted according to the understanding of those skilled in the art.

[0039] In the description of this application, unless otherwise expressly defined, terms such as "setup," "installation," and "connection" should be interpreted broadly, and those skilled in the art can reasonably determine the specific meaning of the above terms in this application in conjunction with the specific content of the technical solution.

[0040] The embodiments of this application are described in detail below. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this application, and should not be construed as limiting this application. The step numbers in the following embodiments are set only for ease of explanation, and there is no limitation on the order between the steps. The execution order of each step in the embodiments can be adaptively adjusted according to the understanding of those skilled in the art.

[0041] In the description of this application, unless otherwise expressly defined, terms such as "setup," "installation," and "connection" should be interpreted broadly, and those skilled in the art can reasonably determine the specific meaning of the above terms in this application in conjunction with the specific content of the technical solution.

[0042] In this application, to facilitate understanding of the relevant technical solutions, some terms are explained as follows: The catenary equation is a curve model formed by a flexible cable structure under its own weight. It is used to describe the spatial shape of a catwalk under gravity, and its parameters reflect the stress state and geometric characteristics of the structure.

[0043] The fourth-order Runge-Kutta method is a commonly used numerical calculation method that improves the accuracy of solving differential equations through multiple weighted calculations. In this application, it is used to solve the equation of a catenary.

[0044] Newton's iteration method is a parameter solving method based on derivative information. It gradually approximates the optimal solution through iteration and is used in this application to optimize the parameters of the catenary equation.

[0045] Multi-base station joint RTK calculation refers to a method that improves positioning accuracy by differentially correcting observation data through multiple GNSS reference stations, thereby achieving high-precision spatial positioning.

[0046] Kalman filtering is a filtering method used for dynamic system state estimation. In this application, it is used to smooth GNSS acquired data to reduce the impact of random noise.

[0047] Moving median filtering is a processing method that takes the median of data within a certain sliding window as the output, used to remove outliers and improve data stability.

[0048] The golden section method is a numerical optimization method for finding the maximum and minimum values ​​of a function. It determines the minimum value by continuously narrowing the search interval, and is used in this application to calculate the minimum distance.

[0049] Three-dimensional Euclidean distance refers to the straight-line distance between two points in three-dimensional space, used to reflect the actual spatial interval between two objects.

[0050] The 3σ principle is a threshold determination method based on statistical distribution. It is used to determine a reasonable range based on historical data, thereby assisting in the setting of safety thresholds.

[0051] The dynamic adjustment method refers to the method of real-time correction of relevant thresholds or control parameters based on environmental parameters and operating status during construction, in order to improve the system's adaptability.

[0052] Control commands refer to adjustment signals generated by the early warning control module and sent to the execution control module, used to control the operating status of the equipment, including but not limited to speed adjustment, direction adjustment and tension control.

[0053] Closed-loop control refers to a control method that continuously monitors and adjusts the system's operating status in real time based on a feedback mechanism. Its basic process includes data acquisition, calculation and analysis, control output, and feedback correction.

[0054] Multi-device collaborative control refers to a control method that coordinates and adjusts multiple devices such as catwalks, idlers, and pullers in a unified manner to ensure the safety and stability of the overall system operation.

[0055] The English abbreviations and explanations used in this application are detailed in Table 1.

[0056] Table 1. English Abbreviations and Explanations

[0057] In this embodiment, as Figure 1 As shown, this application provides a bridge catenary construction safety monitoring and control system 100 based on GNSS data, including a GNSS data acquisition module 110, a data processing center 120, a threshold setting module 130, an early warning control module 140, an execution control module 150, and a multi-device collaborative control module 160. The modules are interconnected to achieve data acquisition, catenary equation reconstruction, safety distance calculation, preset threshold determination, risk early warning, execution control, and multi-device collaborative adjustment during catenary construction.

[0058] The GNSS data acquisition module 110 is used to acquire the coordinates of multiple monitoring points deployed on the catwalk and the real-time coordinates of the traction device, and transmits the acquired coordinates of the multiple monitoring points deployed on the catwalk and the real-time coordinates of the traction device to the data processing center 120. Specifically, the GNSS data acquisition module 110 can use a multi-GNSS system integrated processing method to obtain the real-time coordinates of the traction device. The multi-GNSS system integrated processing method includes at least two of GPS, BeiDou and GLONASS, and performs Kalman filtering on the real-time coordinates of the traction device to reduce the impact of random noise on the coordinate data in the dynamic construction environment and improve the stability and reliability of the real-time positioning results of the traction device.

[0059] The data processing center 120 is used to reconstruct the catenary equation based on the coordinates of multiple monitoring points, and to calculate the safe distance between the catenary and the puller, as well as the safe distance between the idler roller and the puller, based on the catenary equation and the real-time coordinates of the puller.

[0060] Specifically, the data processing center 120 includes a catenary equation calculation submodule. This submodule performs moving median filtering preprocessing on the coordinates of multiple monitoring points, and then corrects the preprocessed coordinates using multi-base station joint RTK calculation. Finally, it solves the catenary equation of the catwalk based on the fourth-order Runge-Kutta method and Newton's iteration method. This allows the current spatial shape of the catwalk to be obtained from the real-time coordinates of multiple discrete monitoring points, providing a dynamic basis for calculating safety clearance.

[0061] In this embodiment, the calculation of safety clearance includes calculating the safety clearance between the catwalk and the puller, and the safety clearance between the idler roller and the puller. Specifically, the safety clearance between the catwalk and the puller is calculated using the minimum distance based on the curve corresponding to the catwalk catenary equation. That is, the minimum distance between the puller and the catwalk curve is determined based on the reconstructed catwalk catenary equation, and this minimum distance is used as the safety clearance between the catwalk and the puller. The safety clearance between the idler roller and the puller is calculated using three-dimensional Euclidean distance, that is, the safety clearance between the idler roller and the puller is determined based on the spatial distance between the idler roller coordinates and the real-time coordinates of the puller. By employing distance calculation methods that match the spatial relationships of different components, the accuracy of safety clearance assessment can be improved.

[0062] The threshold setting module 130 is used to determine the preset threshold corresponding to the safety distance based on theoretical calculation results, historical construction data, and construction condition parameters. Specifically, those skilled in the art will understand that the preset threshold can be determined using, but is not limited to, the following methods: the foundation threshold is determined through theoretical calculation, empirical statistical methods, and dynamic adjustment methods. Specifically, the theoretical calculation method determines the foundation threshold based on the safety factor and component geometry; the empirical statistical method verifies the foundation threshold using the 3σ principle based on historical construction distance data; and the dynamic adjustment method corrects the foundation threshold based on at least one of the construction condition parameters: crosswind speed, catwalk load, and puller speed. This allows the preset threshold to be dynamically adjusted according to changes in the construction environment and operating status, avoiding the problem that a fixed threshold is difficult to adapt to complex construction conditions.

[0063] The early warning control module 140 compares the safe distance with a preset threshold and outputs an early warning signal and control command when the safe distance is less than the preset threshold. In this embodiment, the early warning control module 140 adopts a three-level early warning mechanism: the first early warning level corresponds to a safe distance less than 1.5 times the preset threshold, the second early warning level corresponds to a safe distance less than 1.2 times the preset threshold, and the third early warning level corresponds to a safe distance less than the preset threshold. Specifically, the first early warning level corresponds to a visual alarm, the second early warning level corresponds to an audible and visual alarm and outputs a speed reduction command, and the third early warning level corresponds to an emergency braking command. Through this graded early warning mechanism, different intensities of early warning and control responses can be output according to the degree of risk, improving the timeliness and pertinence of risk management at the construction site.

[0064] The execution control module 150 is used to adjust the operating status of the winch and the parameters of the traction system according to the control command, so that the safety distance is increased to not less than a preset threshold. Specifically, after receiving the control command, the execution control module 150 adjusts the operating speed of the winch proportionally according to the three-level early warning mechanism, and controls the winch to stop running and activate the braking system at the third early warning level.

[0065] Furthermore, the execution control module 150 is also used to calculate the deviation based on the safety clearance and the preset threshold, then calculate the traction control quantity of the puller based on the deviation, and generate an avoidance path control command based on the traction control quantity of the puller; the execution control module 150 is also used to automatically increase the traction tension when the safety clearance is less than the preset threshold, and control the idler to enter the braking state and / or adjust the idler angle. Thus, the system can not only output warning signals, but also achieve automated closed-loop control by adjusting the working status of the winch, traction system, puller and idler.

[0066] In this embodiment, the multi-device collaborative control module 160 coordinates the control commands for the catwalk, idler rollers, and pullers, and outputs them according to a priority relationship of safety over efficiency and efficiency over accuracy. Furthermore, the multi-device collaborative control module 160 also compensates for communication delays to adjust control parameters in advance based on prediction results. By setting up the multi-device collaborative control module 160, control conflicts caused by individual actions between the executing devices can be avoided, enabling the catwalk, idler rollers, and pullers to operate collaboratively under the same control logic, thereby improving the overall control stability and construction safety of the system.

[0067] Through the above system structure, this application can continuously monitor the spatial status of the catenary, idler rollers, and pullers using real-time GNSS positioning data, and calculate the safety distance in real time based on the reconstruction results of the catenary equation of the catenary. Then, it can perform risk judgment and graded early warning by combining dynamically determined preset thresholds. Finally, through the execution control module 150 and the multi-device collaborative control module 160, the operating status of the winch, traction system parameters, puller direction, traction tension, and idler roller status are coordinated and adjusted so that the safety distance during construction is restored to above the preset threshold, thereby realizing the closed-loop and real-time monitoring and control of bridge catenary construction safety.

[0068] like Figure 2 As shown, this application provides a method for safety monitoring and control of bridge catwalk construction based on GNSS data, including the following steps: S1 collects the coordinates of multiple monitoring points deployed on the catwalk and the real-time coordinates of the pullers, and sends the collected data to the data processing center. S2, reconstruct the catenary equation based on the coordinates of multiple monitoring points, and calculate the safe distance between the catenary and the puller and the safe distance between the idler roller and the puller based on the catenary equation and the real-time coordinates of the puller. S3, determine the preset threshold corresponding to the safety distance based on theoretical calculation results, historical construction data and construction condition parameters; S4 compares the safe distance with a preset threshold, and outputs a warning signal and control command when the safe distance is less than the preset threshold; S5 adjusts the winch operating status and traction system parameters according to control commands to increase the safety distance to no less than the preset threshold.

[0069] In this embodiment, the specific implementation process of the system is described.

[0070] Step 1: GNSS Data Acquisition and Preprocessing In this embodiment, the GNSS data acquisition module 110 uses a multi-GNSS system integrated processing method to obtain the real-time coordinates of the puller, including at least two systems among GPS, BeiDou and GLONASS.

[0071] In some implementations, the acquired data is processed using Kalman filtering to eliminate noise interference.

[0072] For catwalk monitoring point data, in some embodiments, a moving median filter algorithm is used for preprocessing:

[0073] In the formula, filtered_point : The coordinates of the monitoring points (three-dimensional vector) after filtering.

[0074] median Median operation: Takes the median of all sampled points within the window.

[0075] GNSS_data : The original coordinate sequence acquired by GNSS.

[0076] i : Index of the current sampling point.

[0077] The sliding window size is 24 sampling points.

[0078] In some implementations, multi-base station joint RTK calculation technology can also be used to correct the data to improve positioning accuracy.

[0079] Step 2: Reconstructing the equations of the catenary path In this embodiment, the catenary equation calculation submodule in the data processing center 120 uses the fourth-order Runge-Kutta method combined with Newton's iteration method to solve the catenary equation.

[0080] Establish a coordinate system with the lowest point of the catwalk as the origin. The equation of the catenary is:

[0081] In the formula, z: Vertical height of the catwalk at the horizontal coordinate x (m).

[0082] a: The shape parameters of the catenary are related to the horizontal tension and weight per unit length of the catwalk support cable 4 (m).

[0083] x: Horizontal coordinate (m, with the lowest point of the catwalk as the origin) along the catwalk span.

[0084] b: Horizontal offset (m) of the lowest point of the catenary.

[0085] c: Vertical offset constant (m) of the catenary, used to adjust the overall height.

[0086] Construct the objective function:

[0087] In the formula, F: the objective function value, i.e., the sum of squared residuals.

[0088] z i : Measured vertical coordinate (m) of the i-th GNSS monitoring point.

[0089] x i : The horizontal coordinate (m) of the i-th monitoring point.

[0090] The parameters are updated as follows:

[0091]

[0092]

[0093] In the formula, a new ,b new ,c new : Updated catenary parameters.

[0094] a, b, c: Parameters for the current iteration step.

[0095] The error is calculated as follows:

[0096] In the formula, error is the sum of the absolute values ​​of the parameter changes in two consecutive iterations, used to determine whether convergence has occurred.

[0097] By iterating until the accuracy requirements are met, the catenary equation can be reconstructed in real time.

[0098] Step 3: Calculation of safety clearance (1) Safety distance between cat walkway and pull-out device Parameterize the catenary equation:

[0099] Distance function:

[0100] In the formula, D(t): Euclidean distance (m) from the puller to the point corresponding to parameter t on the equation of the catenary.

[0101] x p , z p : Horizontal and vertical coordinates (m) of the puller.

[0102] t: Catenary curve parameter, representing the horizontal coordinate.

[0103] f(t): The equation of the catenary z=acosh((t) b) / a)+c.

[0104] minimize D(t) To obtain the minimum safe distance d min .

[0105] Find the minimum value using the golden section method:

[0106] Wherein, minimum distance d min This serves as a safe distance between the catwalk and the pull-out device.

[0107] (2) Safety distance between idler roller and puller Using the three-dimensional Euclidean distance formula:

[0108] In the formula, d: the straight-line distance (m) between the idler roller and the puller.

[0109] x1, y1, z1: ​​The three-dimensional coordinates (m) of the idler roller.

[0110] x2, y2, z2: The three-dimensional coordinates (m) of the puller.

[0111] The calculation result serves as the safe distance between the idler roller and the puller.

[0112] Step 4: Determine the preset threshold (1) Basic threshold (theoretical calculation method) Catwalk and Puller:

[0113] In the formula, d threshold_catwalk : The baseline threshold (m) for the safe distance between the catwalk and the puller.

[0114] D rope : Geometric dimensions of the puller or rope (e.g., diameter, m).

[0115] S clearance Additional safety margin (m).

[0116] Idler rollers and pullers:

[0117] In the formula, d threshold_roller : The baseline threshold (m) for the safety clearance between the idler roller and the puller.

[0118] k2: Safety factor.

[0119] R roller : Radius of the idler roller (m).

[0120] R tug : Equivalent radius of the puller (m).

[0121] S vibration Additional margin (m) considering dynamic factors such as vibration and impact.

[0122] (2) Empirical statistical method

[0123] In the formula, threshold: A safety threshold obtained based on historical data statistics.

[0124] μ : The average value (m) of historical construction spacing data.

[0125] σ Standard deviation (m) of historical construction spacing data.

[0126] 3 σ The three-standard-deviation rule is used to determine a reasonable lower limit.

[0127] (3) Dynamic adjustment method If the crosswind speed is >10 m / s:

[0128] elif Catwalk load > Design load × 0.8:

[0129] elif puller speed > 0.5m / s:

[0130] else:

[0131] In the formula, threshold: the final safety threshold (m) after dynamic adjustment.

[0132] base_threshold: A baseline threshold (m) obtained from theory or empirical statistics. The preset threshold is finally obtained.

[0133] Step 5: Early Warning and Control A three-tiered early warning mechanism is adopted: Level 1 Warning: ; Level 2 warning: ; Level 3 Warning: ; Among them: Level 1 warning outputs visual alarm; Level 2 warning outputs audible and visual alarm and control commands; Level 3 warning outputs emergency braking control commands.

[0134] Step Six: Execution Control (1) Winch control (Level 1) ； (Level 2) ； (Level 3) 。

[0135] In the formula, V new Adjusted winch operating speed (m / s).

[0136] V current Current winch operating speed (m / s) (2) Direction control The maximum steering angle is ±15°. In the formula, Δ θ The change in the directional angle (°) that the puller needs to be adjusted for.

[0137] k p : Proportional control gain (° / m).

[0138] d threshold : Safety threshold (m) under the current operating conditions.

[0139] d current : The safe distance (m) measured in real time.

[0140] (3) Tension control .

[0141] In the formula, T new Increased traction tension (kN).

[0142] T current Current traction tension (kN).

[0143] (4) Idler control .

[0144] In the formula, αnew : Adjusted idler roller angle (°).

[0145] α current Current idler roller angle (°).

[0146] d threshold : Safety threshold (m).

[0147] d current Real-time safety clearance (m) Step 7: Multi-device collaborative control: In some implementations, the system also includes a multi-device collaborative control module 160 for collaborative control of the catwalk, idlers, and pullers.

[0148] The control priority is: safety > efficiency > accuracy; and communication delay is compensated for through a prediction algorithm.

[0149] Communication delay refers to the time consumed from the acquisition of coordinate data of the puller or catwalk monitoring point by the GNSS data acquisition module, through wireless network to the data processing center, where the data processing center calculates the safety distance and makes early warning judgments, and then through the control network to transmit control commands to the execution control module to drive the winch or puller to execute the control module's response. This includes, but is not limited to, data transmission delay, data processing delay, and control response delay. Prediction result refers to the spatial coordinates or catwalk catenary morphology parameters of the puller and / or catwalk monitoring point at a future time (usually the time after the communication delay ends), calculated using Kalman filtering or a uniform acceleration motion model, based on the historical motion trajectory, current speed, and acceleration of the puller and / or catwalk. The system further calculates the future safety distance based on this prediction result and compares it with a preset threshold to generate control commands in advance.

[0150] Application Examples like Figure 3 and Figure 4 As shown, in this embodiment, the construction of a catwalk for a suspension bridge is taken as an example: The GNSS sampling frequency is 10Hz, the filtering window is 24 sampling points, and the crosswind speed is 12m / s.

[0151] According to the dynamic adjustment rules: ; When the detected safe distance is less than 1.2 times the preset threshold, a level 2 warning is triggered: The speed of the winch 500 was reduced to 50%; The acceleration is limited to 0.05 m / s². Simultaneously, directional and tension adjustments are performed to restore the safety clearance to a safe range.

[0152] In this embodiment, as Figure 1 As shown, this paper presents a deployment and implementation method for a bridge catwalk construction safety monitoring and control system based on GNSS data. The system includes a GNSS data acquisition module, a data processing center, a threshold setting module, an early warning control module, and an execution control module. This system is applied during bridge catwalk construction to monitor the catwalk alignment, the position of the traction device, and the relative distance between the roller and the traction device in real time, and to provide early warnings and control when the safety clearance is insufficient.

[0153] Specifically, GNSS reference stations are installed at the anchor points at both ends of the catenary, the lowest point at mid-span, and at the 1 / 4 and 3 / 4 span positions of the catenary. These GNSS reference stations provide positioning benchmarks within the catenary construction area and, in conjunction with GNSS monitoring points and high-precision GNSS receivers, obtain real-time coordinate data of the catenary and construction equipment. By setting up GNSS reference stations at the anchor points at both ends, the reference coordinates of the constrained positions at both ends of the catenary can be obtained; by setting up a GNSS reference station at the lowest point at mid-span, positioning data at the location where the catenary's vertical change is most significant can be obtained; and by setting up GNSS reference stations at the 1 / 4 and 3 / 4 span positions, the linear changes of the catenary's spans on both sides can be further reflected, thus providing basic data for the subsequent reconstruction of the catenary's catenary equation.

[0154] Furthermore, GNSS monitoring points are installed at key nodes of the catwalk. Preferably, GNSS monitoring points are deployed along the catwalk's extension direction at 20m intervals to collect the three-dimensional coordinates of multiple discrete locations along the catwalk. After the data collected by the GNSS monitoring points is transmitted to the data processing center, the center reconstructs the catenary equation of the catwalk based on the coordinates of multiple monitoring points and calculates the real-time alignment of the catwalk during construction. By deploying GNSS monitoring points at intervals, the accuracy of the catwalk alignment fitting can be improved, avoiding the problem of inaccurate identification of local deformations caused by relying on only a small number of measuring points.

[0155] Furthermore, high-precision GNSS receivers are installed on each idler roller and puller. These receivers acquire the real-time spatial coordinates of the idler roller and puller. Specifically, the high-precision GNSS receiver on the puller is used to collect its real-time movement position during traction, while the high-precision GNSS receiver on the idler roller is used to collect the spatial coordinates corresponding to changes in idler roller position or the idler roller's operating state. The data processing center calculates the safe clearance between the catenary and the puller, as well as the safe clearance between the idler roller and the puller, based on the catenary equation, the idler roller coordinates, and the real-time coordinates of the puller.

[0156] Furthermore, a wireless data transmission network is established. This network communicates with the GNSS reference station, GNSS monitoring points, high-precision GNSS receivers, and the data processing center to achieve real-time transmission of positioning data. Through this network, the system can continuously transmit the real-time coordinates of the catwalk, idler rollers, and pullers to the data processing center, ensuring the real-time performance of safety distance calculations and early warning control.

[0157] In terms of software implementation, the data processing center uses Python to develop the core algorithm module and data visualization interface. The core algorithm module processes GNSS data, reconstructs the catenary equation for the catenary walkway, calculates the safe clearance between the catenary walkway and the traction device, as well as the safe clearance between the idler roller and the traction device, and outputs the calculation results to the early warning control module. The data visualization interface displays the catenary walkway alignment, traction device position, idler roller position, and current safe clearance status in real time, allowing construction personnel to intuitively grasp the safety status of the catenary walkway construction.

[0158] Furthermore, the execution control module communicates with the winch control system based on the OPC UA protocol. When the early warning control module determines that the safe distance is less than a preset threshold, it generates a control command and sends it to the execution control module. The execution control module transmits the control command to the winch control system via the OPC UA protocol to adjust the winch's operating status and traction system parameters. Adjustments include at least one of reducing the winch's operating speed, limiting acceleration, adjusting traction tension, or executing an emergency stop.

[0159] Furthermore, the data processing center uses a Redis database to store historical construction data. This historical data includes at least one of the following: coordinates of the catwalk monitoring points, coordinates of the idler rollers, real-time coordinates of the pullers, calculated safety clearances, preset thresholds, early warning records, and control command records. Storing this historical data in a Redis database supports data analysis during the construction process, retrospective analysis of abnormal working conditions, and the retrieval of historical construction data by the threshold setting module, thereby improving the rationality of safety clearance threshold settings and the reliability of system control.

[0160] Through the above deployment and software implementation methods, this embodiment can realize the real-time acquisition of multi-point positioning data during the construction of the catenary, the dynamic reconstruction of the catenary equation, the real-time calculation of the safety distance, the timely output of early warning signals, and the linkage control of the winch and traction system, thereby improving the safety and automation control level of the bridge catenary construction process.

[0161] In one specific embodiment, such as Figure 3 and Figure 4As shown, the bridge catwalk is divided into multiple monitoring sections along the longitudinal direction, and GNSS monitoring equipment is installed at key points along the catwalk. The GNSS monitoring equipment is used to collect three-dimensional coordinate data of the corresponding locations on the catwalk and sends this data to the data processing center. Based on the coordinate data collected by multiple GNSS monitoring devices, the data processing center calculates the real-time alignment of the catwalk and, according to the real-time alignment, calculates the safe distances between the catwalk and the traction device, and between the idler roller and the traction device.

[0162] The first anchor 1 and the second anchor 5 are respectively located on the foundation structures on both banks of the bridge or on the sides of the tower. The two ends of the main cable 3 are anchored to the first anchor 1 and the second anchor 5, forming the main load-bearing structure of the suspension bridge. The catwalk load-bearing cable 4 is anchored to the two anchors at both ends, serving as the main load-bearing cable for the catwalk (temporary construction platform). One end of the traction cable 2 is connected to the puller (not shown in the attached diagram), and the other end is connected to the winch (not shown in the attached diagram). The puller moves on the main cable 3 or the catwalk load-bearing cable 4, and the traction cable 2 is used to control the operating position of the puller. The catwalk load-bearing cable 4 is usually arranged below or to the side of the main cable 3 to suspend the catwalk surface. Idler rollers are installed on the catwalk load-bearing cable 4 to support and guide the movement of the puller. The idler rollers are fixed to the catwalk load-bearing cable 4, and the puller moves along the idler rollers or the traction cable 2; the spatial distance between them is monitored in real time by a GNSS module.

[0163] In Example 1, the GNSS monitoring equipment is positioned at the eighth-quarter point of the catenary. By deploying the GNSS monitoring equipment at the eighth-quarter point of the catenary, real-time coordinates of multiple discrete positions along the span direction of the catenary can be obtained, enabling the system to accurately fit the catenary equation and determine the overall deformation state of the catenary during construction. This arrangement is suitable for construction conditions requiring high accuracy in alignment monitoring during the construction of long-span catenaries.

[0164] In another embodiment, different monitoring points are deployed for different spans. Specifically, a monitoring device is installed at the quarter-point of the left side span, at the fourteenth-point of the middle span, and at the seventh-point of the right side span. The quarter-point deployment on the left side span acquires key alignment change data for the catenary walkway; the fourteenth-point deployment on the middle span increases the coordinate sampling density of the catenary walkway, enabling a more accurate fit to the catenary alignment; and the seventh-point deployment on the right side span acquires key positional change data for the right side catenary walkway. Thus, the system can perform differentiated monitoring based on the length, deformation characteristics, and construction risks of different spans, improving the targeting and cost-effectiveness of GNSS monitoring equipment deployment.

[0165] Through the above deployment method, the system can continuously obtain the real-time coordinates of key locations on the catwalk and, combined with the real-time positions of construction equipment such as pullers and rollers, calculate the minimum safe distance between various components during construction. When the minimum safe distance is lower than a preset threshold, the system issues a corresponding level of warning signal and generates control commands such as winch deceleration, traction system braking, tension adjustment, or direction adjustment based on a three-level warning mechanism, thereby achieving real-time safety monitoring and intelligent control during the construction of the bridge catwalk.

[0166] Based on the above description, this application has the following advantages: 1. Multi-source GNSS data fusion algorithm: For the first time, the multi-GNSS system integration processing method is applied to the monitoring of catwalk construction. Through ambiguity fixation optimization technology, the positioning accuracy is improved to the centimeter level.

[0167] 2. Real-time solution of dynamic catenary equation: The fourth-order Runge-Kutta method combined with the second-order Newton method is used to realize the fast and accurate solution of the catenary equation under complex working conditions, and the computational efficiency is improved by more than 40% compared with the traditional method.

[0168] 3. Adaptive threshold setting mechanism: An innovative triple threshold setting method based on theoretical calculation, empirical statistics and dynamic adjustment is proposed, which can automatically adjust the safety threshold according to the construction environment and working conditions, significantly reducing the false alarm rate and the missed alarm rate.

[0169] 4. Intelligent hierarchical control strategy: A three-level early warning and hierarchical control system based on spacing monitoring was established, realizing intelligent control of the entire process from early warning and reminder to automatic adjustment, filling the technical gap in automated control of bridge construction safety.

[0170] 5. Multi-device collaborative control algorithm: For the first time in bridge construction, multi-device collaborative control of catwalk, idler roller, and puller is realized. Through real-time data sharing and command optimization, the overall safety and construction efficiency of the system are ensured.

[0171] This application combines real-time GNSS positioning data with dynamic reconstruction of the catenary equation of the bridge catenary, and integrates a multi-source threshold setting mechanism that combines theoretical calculation, empirical statistics and dynamic adjustment to achieve a closed-loop control process from state perception and risk assessment to automatic control, thereby significantly improving the safety, real-time performance and reliability of the bridge catenary construction process.

[0172] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0173] These computer program instructions can also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0174] This application may take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this application may take the form of a computer program product implemented on one or more computer-usable storage media (including, but not limited to, disk storage, readable storage media, optical storage, etc.) containing computer-usable program code.

[0175] This application is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of this application. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart... Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0176] Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of this application.

[0177] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application and not to limit them. Although this application has been described in detail with reference to the above embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the specific implementation methods of this application. Any modifications or equivalent substitutions that do not depart from the spirit and scope of this application should be covered within the protection scope of this application.

Claims

1. A bridge catwalk construction safety monitoring and control system based on GNSS data, characterized in that, It includes a GNSS data acquisition module, a data processing center, a threshold setting module, an early warning control module, and an execution control module; The GNSS data acquisition module is used to acquire the coordinates of multiple monitoring points deployed on the catwalk and the real-time coordinates deployed on the puller, and transmit the acquired coordinates of multiple monitoring points deployed on the catwalk and the real-time coordinates deployed on the puller to the data processing center. The data processing center is used to reconstruct the catenary equation based on the coordinates of the multiple monitoring points, and to calculate the safe distance between the catenary and the puller, as well as the safe distance between the idler roller and the puller, based on the catenary equation and the real-time coordinates of the puller. The threshold setting module is used to determine the preset threshold corresponding to the safety distance; The early warning control module is used to compare the safety distance with the preset threshold, and output an early warning signal and control command when the safety distance is less than the preset threshold; The execution control module is used to adjust the operating status of the winch and the parameters of the traction system according to the control command, so that the safety distance is increased to not less than the preset threshold.

2. The bridge catwalk construction safety monitoring and control system based on GNSS data according to claim 1, characterized in that, The data processing center includes a catenary equation calculation submodule, which is used to perform moving median filtering preprocessing on the coordinates of the multiple monitoring points, and after correcting the preprocessed coordinates by multi-base station joint RTK calculation, solve the catenary equation based on the fourth-order Runge-Kutta method and Newton's iteration method.

3. The bridge catwalk construction safety monitoring and control system based on GNSS data according to claim 1, characterized in that, The GNSS data acquisition module uses a multi-GNSS system integration processing method to obtain the real-time coordinates of the puller. The multi-GNSS system integration processing method includes at least two of GPS, BeiDou and GLONASS, and performs Kalman filtering processing on the real-time coordinates of the puller.

4. The bridge catwalk construction safety monitoring and control system based on GNSS data according to claim 1, characterized in that, The calculation of the safety distance includes: the safety distance between the catwalk and the puller is calculated using the minimum distance based on the curve corresponding to the catwalk catenary equation; and the safety distance between the idler roller and the puller is calculated using three-dimensional Euclidean distance.

5. The bridge catwalk construction safety monitoring and control system based on GNSS data according to claim 1, characterized in that, The preset threshold is determined by theoretical calculation, empirical statistical method and dynamic adjustment method; The theoretical calculation method determines the foundation threshold based on the safety factor and component geometry. The empirical statistical method verifies the foundation threshold using the 3σ principle based on historical construction spacing data. The dynamic adjustment method corrects the foundation threshold based on at least one working condition parameter among crosswind speed, catwalk load, and puller speed to obtain the final preset threshold.

6. The bridge catwalk construction safety monitoring and control system based on GNSS data according to claim 1, characterized in that, The early warning control module adopts a three-level early warning mechanism. The first early warning level corresponds to the safety distance being (1.5~1.2) times the preset threshold, the second early warning level corresponds to the safety distance being (1.2~1.0) times the preset threshold, and the third early warning level corresponds to the safety distance being less than the preset threshold. The first warning level corresponds to a visual alarm, the second warning level corresponds to an audible and visual alarm and outputs a deceleration command, and the third warning level corresponds to an emergency braking command.

7. The bridge catwalk construction safety monitoring and control system based on GNSS data according to claim 6, characterized in that, After receiving the control command, the execution control module adjusts the operating speed of the winch proportionally according to the three-level early warning mechanism, and controls the winch to stop running and activate the braking system at the third early warning level.

8. The bridge catwalk construction safety monitoring and control system based on GNSS data according to claim 1, characterized in that, The execution control module is also used to calculate the deviation based on the safety distance and the preset threshold, calculate the puller direction control amount based on the deviation, and generate an avoidance path control command based on the puller direction control amount. The execution control module is also used to automatically increase the traction tension when the safety distance is less than the preset threshold, and control the idler to enter the braking state and / or adjust the idler angle.

9. The bridge catwalk construction safety monitoring and control system based on GNSS data according to claim 1, characterized in that, It also includes a multi-device collaborative control module, which coordinates the control commands of the cat track, idler rollers and pullers, and outputs them according to the priority relationship of safety over efficiency and efficiency over accuracy. The multi-device collaborative control module is also used to compensate for communication delays so as to adjust control parameters in advance based on the prediction results; wherein, the communication delay includes the data transmission delay from the GNSS data acquisition module to the data processing center, the data processing delay of the data processing center, and the response delay from the control command to the execution control module; the prediction results are the spatial coordinates or safety distance of the puller or catwalk at future times calculated based on historical motion data.

10. A method for monitoring and controlling the construction safety of a bridge catwalk based on GNSS data, based on the bridge catwalk construction safety monitoring and control system based on GNSS data as described in any one of claims 1 to 9, characterized in that, Includes the following steps: S1 collects the coordinates of multiple monitoring points deployed on the catwalk and the real-time coordinates of the pullers, and sends the collected data to the data processing center. S2, Reconstruct the catenary equation based on the coordinates of the multiple monitoring points, and calculate the safe distance between the catenary and the puller and the safe distance between the idler roller and the puller based on the catenary equation and the real-time coordinates of the puller. S3, determine the preset threshold corresponding to the safety distance based on theoretical calculation results, historical construction data and construction condition parameters; S4, compare the safety distance with the preset threshold, and output a warning signal and control command when the safety distance is less than the preset threshold; S5, adjust the winch operating status and traction system parameters according to the control command so that the safety distance is increased to not less than the preset threshold.

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