A measurement system, method and device for multi-point synchronous measurement of bridge vibration

Abstract

The application discloses a kind of measurement system, method and equipment for measuring bridge vibration by multipoint synchronous measurement, it is related to bridge monitoring field, measurement system includes: EtherCAT master station and multiple EtherCAT slave stations;Multiple EtherCAT slave stations are connected, and first EtherCAT slave station is connected with EtherCAT master station;Each EtherCAT slave station is connected with one vibration sensor, and vibration sensor is used to measure the vibration data of bridge at each EtherCAT slave station measuring point;EtherCAT master station synchronizes the clock of EtherCAT slave station by the synchronization mechanism of EtherCAT protocol, controls the vibration data of EtherCAT slave station synchronous measurement, and vibration data is transmitted to EtherCAT master station by Ethernet with the data format of EtherCAT protocol;EtherCAT master station is used for the vibration of bridge at each EtherCAT slave station measuring point, analyzes the propagation of bridge vibration wave between adjacent measuring points, to monitor the current state of bridge;The current state includes normal state and damage state.The application can analyze the propagation characteristics of vibration wave between each measuring point, and monitor the current state of bridge.

Description

Technical Field

[0001] This invention relates to the field of bridge monitoring, and in particular to a measurement system, method and equipment for multi-point synchronous measurement of bridge vibration. Background Technology

[0002] Modern bridges are crucial nodes on main roads and play a vital role in the national economy. The safety of long-span bridges is receiving increasing attention. Economic development has spurred the development of transportation, leading to ever-increasing transport volumes, traffic density, and vehicle loads.

[0003] Over the long term, bridges suffer structural damage and functional degradation due to environmental erosion, material aging, increased traffic volume, and the increase in heavy and overweight vehicles crossing the bridge.

[0004] Several existing bridges suffer from significant problems. First, their initial design standards were low, and after a period of development, their load-bearing capacity no longer meets the needs of modern transportation. Second, their structures are outdated, aging, and damaged, affecting their original design capabilities and jeopardizing their operation. Bridges are generally expensive to build and have long service lives. The combined effects of environmental erosion, material aging, long-term load effects, fatigue effects, and sudden change effects lead to accumulated structural damage and weakened resistance. All of these factors hinder the development of transportation and pose significant challenges to the current operation, maintenance, and management of bridges.

[0005] Monitoring, diagnosis, damage assessment, and safety early warning of bridge performance have become essential requirements for bridge construction. Factors contributing to bridge vibration include vehicle engine vibration, uneven road surfaces, pedestrian loads, wind loads, and earthquakes. Increased vehicle numbers, load capacities, and speeds all contribute to increased bridge vibration. For long-span and super-span bridges, vehicle vibration and other dynamic loads have become crucial factors in bridge design, construction, management, maintenance, and repair.

[0006] Bridge vibration monitoring utilizes vibration sensors to measure and analyze the bridge's dynamic characteristics, forced vibration response, and dynamic load characteristics. Structural dynamic characteristics include natural frequencies, damping characteristics, and vibration patterns. Forced vibration response includes amplitude, dynamic stress, and acceleration. Dynamic load characteristics include the magnitude, direction, frequency, and application pattern of the forces causing structural vibration.

[0007] Current methods for bridge vibration testing include the following:

[0008] 1. Single-point wired measurement: Single-point measurement for a single target point. Or, measurement for multiple target points, one by one.

[0009] 2. Asynchronous wired measurement at multiple points within a small area: Asynchronous measurement of vibration at multiple points within a small area (within tens of meters).

[0010] However, for wired measurements and small-range, multi-point asynchronous finite measurements, the solution is complex and wiring is troublesome if you want to measure a long-distance bridge.

[0011] 3. Large-area, multi-point asynchronous wireless measurement: Vibration is measured at multiple points over a large area wirelessly. This primarily uses polling or interrupt methods to transmit measurement data wirelessly, saving on wiring. However, the multi-point measurement method is asynchronous; while it can measure multiple points, it cannot analyze the propagation characteristics of vibration waves between each measurement point (mainly adjacent points). Summary of the Invention

[0012] The purpose of this invention is to provide a measurement system, method, and device for multi-point synchronous measurement of bridge vibration, so as to solve the problem of not being able to analyze the propagation characteristics of vibration waves between various measurement points.

[0013] To achieve the above objectives, the present invention provides the following solution:

[0014] A measurement system for multi-point synchronous measurement of bridge vibration includes: an EtherCAT master station and multiple EtherCAT slave stations;

[0015] Multiple EtherCAT slave stations are connected to each other, and the first EtherCAT slave station is connected to the EtherCAT master station; each EtherCAT slave station is connected to a vibration sensor, which is used to measure the vibration data of the bridge at each EtherCAT slave station measurement point;

[0016] The EtherCAT master station synchronizes the clocks of the EtherCAT slave stations through the EtherCAT protocol's synchronization mechanism, controls the EtherCAT slave stations to synchronously measure the vibration data, and transmits the vibration data back to the EtherCAT master station via Ethernet in the EtherCAT protocol data format. The EtherCAT master station is used to monitor the bridge's vibration at each measurement point of the EtherCAT slave station, analyze the propagation of bridge vibration waves between adjacent measurement points, and monitor the bridge's current state, which includes both normal and damaged states.

[0017] Optionally, the EtherCAT slave station specifically includes: a master control chip, an EEPROM storage chip, an LCD / LED module and a button circuit, and a first Ethernet interface, a first network transformer, an EtherCAT control chip, a second network transformer and a second Ethernet interface connected in sequence.

[0018] The main control chip is connected to the EtherCAT control chip, the vibration sensor, the EEPROM storage chip, the LCD / LED module, and the button circuit, respectively.

[0019] The EtherCAT control chip and the main control chip communicate via a parallel I / O interface or an SPI interface; the EtherCAT control chip is used for EtherCAT bus control; the EEPROM storage chip and the EtherCAT control chip communicate via an IIC interface.

[0020] The first Ethernet interface and the second Ethernet interface are RJ45 interfaces used to connect to the EtherCAT master station or an adjacent EtherCAT slave station; the first Ethernet interface is isolated from the EtherCAT control chip through the first network transformer, and the second Ethernet interface is isolated from the EtherCAT control chip through the second network transformer.

[0021] The EEPROM storage chip is used to store the configuration file of the EtherCAT slave station itself;

[0022] In the LCD / LED module, the LCD is used to display the text and graphics of the EtherCAT slave station itself, and the LED is used to display the working status and fault indication of the EtherCAT slave station itself.

[0023] The button circuit is used to set the working mode of the EtherCAT slave station itself.

[0024] A method for simultaneously measuring bridge vibration at multiple points, comprising:

[0025] Configure the basic parameters of the EtherCAT slave station, configure the clock of the EtherCAT slave station based on the EtherCAT protocol, synchronize the clocks of all EtherCAT slave stations and the EtherCAT master station, and write configuration information to the EtherCAT slave station; the basic parameters include manufacturer information and slave station description information; the configuration information includes basic parameters and synchronization clock;

[0026] Based on the configuration information, the temporal characteristics of the bridge vibration data at adjacent measurement points of each EtherCAT slave station are obtained; the temporal characteristics include temporal vibration waveform, spectrum, power spectrum, amplitude, and bridge deck tilt angle.

[0027] The propagation characteristics of bridge vibration waves are determined based on the time-domain characteristics; the propagation characteristics include propagation time, vibration waveform, and spectral waveform.

[0028] The current state of the bridge is determined based on the propagation characteristics; the current state includes both a normal state and a damaged state.

[0029] Optionally, configure the clocks of the EtherCAT slave stations based on the EtherCAT protocol to synchronize the clocks of all EtherCAT slave stations and the EtherCAT master station, specifically including:

[0030] Based on the EtherCAT protocol, the clock of the first EtherCAT slave station with distributed clock function connected to the EtherCAT is used as the reference clock, and the clocks of the remaining EtherCAT slave stations are used as slave clocks.

[0031] Obtain the local clocks of the remaining EtherCAT slaves;

[0032] The initial clock offset is determined based on the reference clock and the local clock;

[0033] The clock drift amount is determined based on the local clock;

[0034] The slave clock is compensated and corrected based on the initial clock offset and the clock drift.

[0035] The master clock of the EtherCAT master station is corrected according to the reference clock.

[0036] Optionally, the master clock of the EtherCAT master station is corrected according to the reference clock, and then the process further includes:

[0037] The EtherCAT master station sends a broadcast command to the EtherCAT slave station to write data frames;

[0038] Based on the write data frame, the EtherCAT slave station writes its local clock into the first receive time port and sends it back to the EtherCAT master station.

[0039] During the backhaul process, the EtherCAT slave station writes its local clock into the second receive time port.

[0040] The EtherCAT master station calculates the local offset time based on the local clock written to the first receiving time port;

[0041] The delay of each EtherCAT slave relative to the reference clock is calculated based on the local clock written to the first receiving time port and the local clock written to the second receiving time port.

[0042] Optionally, determining the current state of the bridge based on the propagation characteristics specifically includes:

[0043] Obtain the propagation characteristics of the bridge under normal conditions;

[0044] By comparing the propagation characteristics of the bridge under normal conditions with the propagation characteristics of the monitored bridge vibration waves, a comparative difference is generated.

[0045] When the difference exceeds a set difference threshold, the current state of the bridge is determined to be a damaged state.

[0046] When the difference in comparison does not exceed the set difference threshold, the current state of the bridge is determined to be normal.

[0047] An electronic device includes a memory and a processor, the memory storing a computer program and the processor running the computer program to enable the electronic device to perform the measurement method for multi-point synchronous measurement of bridge vibration as described above.

[0048] A computer-readable storage medium storing a computer program that, when executed by a processor, implements the measurement method for multi-point synchronous measurement of bridge vibration as described above.

[0049] According to specific embodiments provided by the present invention, the present invention discloses the following technical effects: The present invention provides a measurement system, method and device for multi-point synchronous measurement of bridge vibration, which synchronizes the clock of EtherCAT slave station based on the synchronization mechanism of EtherCAT protocol, controls the EtherCAT slave station to synchronously measure vibration data, determines the vibration status of the bridge at each measurement point of the EtherCAT slave station, and analyzes the propagation of bridge vibration waves between adjacent measurement points to monitor the current state of the bridge. Attached Figure Description

[0050] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0051] Figure 1 A block diagram of the multi-point synchronous measurement system for bridge vibration provided by the present invention;

[0052] Figure 2 This is a block diagram of the EtherCAT slave structure provided by the present invention;

[0053] Figure 3 A flowchart illustrating the multi-point synchronous measurement method for bridge vibration provided by this invention;

[0054] Figure 4This is a schematic diagram of the installation position of the vibration sensor provided by the present invention;

[0055] Figure 5 This is a schematic diagram of the description document provided by the present invention;

[0056] Figure 6 This is a diagram illustrating the time synchronization process.

[0057] Figure 7 This is a schematic diagram showing the specific location of the vibration sensor provided by the present invention. Detailed Implementation

[0058] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0059] The purpose of this invention is to provide a measurement system, method, and device for multi-point synchronous measurement of bridge vibration, which can analyze the propagation characteristics of vibration waves between measurement points and monitor the current state of the bridge.

[0060] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0061] Example 1

[0062] Figure 1 The block diagram of the multi-point synchronous measurement system for bridge vibration provided by the present invention is as follows: Figure 1As shown, a multi-point synchronous measurement system for bridge vibration includes: an EtherCAT master station and multiple EtherCAT slave stations; the multiple EtherCAT slave stations are connected to each other, with the first EtherCAT slave station connected to the EtherCAT master station; each EtherCAT slave station is connected to a vibration sensor, which measures the vibration data of the bridge at each measurement point of the EtherCAT slave station; the EtherCAT master station synchronizes the clocks of the EtherCAT slave stations through the synchronization mechanism of the EtherCAT protocol, controls the EtherCAT slave stations to synchronously measure the vibration data, and transmits the vibration data back to the EtherCAT master station via Ethernet in the EtherCAT protocol data format; the EtherCAT master station is used to monitor the vibration of the bridge at each measurement point of the EtherCAT slave station, analyze the propagation of bridge vibration waves between adjacent measurement points, and monitor the current state of the bridge; the current state includes a normal state and a damaged state.

[0063] In practical applications, the master station uses an EtherCAT master device, and the slave station uses an EtherCAT slave device. The slave station interface uses a single-input, single-output 100M Ethernet interface. The master station and slave station are connected serially via 100M Ethernet. The slave station is connected to the vibration sensor for rapid measurement of vibration data. The vibration sensor can be a single-axis, dual-axis, or triaxial vibration sensor.

[0064] The master station controls the slave stations to synchronously measure vibration data through the synchronization mechanism of the EtherCAT protocol, and transmits the vibration data back to the master station via 100M Ethernet in the EtherCAT protocol data format. The master station calculates and analyzes the vibration data, monitors the vibration of each slave station measurement point, and analyzes the propagation of bridge vibration waves between adjacent measurement points, thereby monitoring the health status of the bridge.

[0065] The main station can be a regular PC or laptop computer with a 100M network port.

[0066] In practical applications, Figure 2 The following is a block diagram of the EtherCAT slave structure provided by the present invention, as follows: Figure 2As shown, the Ethernet interface includes a first Ethernet interface and a second Ethernet interface. The network transformer includes a first network transformer and a second network transformer. The EtherCAT slave station specifically includes: a master control chip, an EEPROM storage chip, an LCD / LED module, and a button circuit, and the first Ethernet interface, the first network transformer, the EtherCAT control chip, the second network transformer, and the second Ethernet interface are connected in sequence. The master control chip is connected to the EtherCAT control chip, the vibration sensor, the EEPROM storage chip, the LCD / LED module, and the button circuit. The EtherCAT control chip communicates with the master control chip via a parallel I / O interface or an SPI interface. The EtherCAT control chip is used for EtherCAT bus control. The EEPROM storage chip communicates with the EtherCAT control chip via an IIC interface. The master control chip is a 32-bit microcontroller, such as an STM32F, and plays a core control role in the device. The EtherCAT control chip is a dedicated chip for EtherCAT slave stations, integrating an Ethernet physical layer, with 2 or 3 Ethernet interfaces and an IIC interface, used in the device to implement EtherCAT bus control.

[0067] The Ethernet interface uses an RJ45 connector, serving as the EtherCAT bus interface. This device connects to other EtherCAT bus devices through this interface. A network transformer isolates the Ethernet interface from the EtherCAT control chip, increasing system reliability.

[0068] The EEPROM uses a 24LC128 chip and is used in the device to store the device's configuration file.

[0069] LCD / LED Module: LCD is used for text and graphic display on the device, while LED is used for system operating status and fault indication.

[0070] The button circuit uses buttons for system input and toggle switches for setting the device's operating mode.

[0071] The EtherCAT control chip and the main control chip communicate with each other via a parallel I / O interface or an SPI interface.

[0072] The EEPROM communicates with the EtherCAT control chip via an IIC interface.

[0073] Example 2

[0074] Figure 3 The flowchart of the multi-point synchronous measurement method for bridge vibration provided by the present invention is as follows: Figure 3As shown, a method for multi-point synchronous measurement of bridge vibration includes:

[0075] Step 301: Configure the basic parameters of the EtherCAT slave station, configure the clock of the EtherCAT slave station based on the EtherCAT protocol, synchronize the clocks of all EtherCAT slave stations and the EtherCAT master station, and write configuration information to the EtherCAT slave station; the basic parameters include manufacturer information and slave station description information; the configuration information includes basic parameters and synchronization clock.

[0076] In practical applications, configuring the clocks of EtherCAT slave stations based on the EtherCAT protocol and synchronizing the clocks of all EtherCAT slave stations and the EtherCAT master station specifically includes: using the clock of the first EtherCAT slave station with distributed clock functionality connected to the EtherCAT as a reference clock, and using the clocks of the remaining EtherCAT slave stations as slave clocks; obtaining the local clocks of the remaining EtherCAT slave stations; determining the initial clock offset based on the reference clock and the local clocks; determining the clock drift based on the local clocks; compensating and correcting the slave clocks based on the initial clock offset and the clock drift; and correcting the master station clock of the EtherCAT master station based on the reference clock.

[0077] Measurement points are typically selected at locations on the bridge deck where stress or deformation is greatest, such as the ends and middle of the bridge deck. Figure 4 This is a schematic diagram of the installation position of the vibration sensor provided by the present invention, as shown below. Figure 4 As shown.

[0078] Further, configure the basic parameters of the slave station:

[0079] The configuration of the slave device is achieved through the slave device description file, which is in XML format. Figure 5 This is a schematic diagram of the description document provided by the present invention. The contents of the document are as follows: Figure 5 As shown, based on the number of slave stations and the type of vibration sensor (single-axis, dual-axis, tri-axis), modify the device identifier, FMMU unit type, number of channels, mapping relationship, SM channel number, size, starting address, process data index, name, type and other parameters in the configuration file to complete the basic parameters of the slave station.

[0080] Further, configure the synchronization clock:

[0081] Configure the slave station's synchronous clock according to the EtherCAT protocol.

[0082] The system measures the actual delay between the slave station control signals and data transmission, automatically records the delay, and uses the delay data to correct and compensate for the clock difference between slave stations, thereby achieving complete synchronization of all slave stations.

[0083] Description of distributed clocks:

[0084] 1. Local Clock. Each distributed slave station generates its own local clock after compensation and synchronization. The distributed clock synchronization mechanism ensures that the local clocks of all slave stations remain consistent. The reference clock corresponds to the local clock.

[0085] 2. Reference Clock and Slave Clock. The EtherCAT protocol specifies that the clock of the first slave station with distributed clock functionality connected to the master station is used as the reference clock, and the clocks of other slave stations are called slave clocks. The reference clock is used to synchronize other slave clocks with the master station clock. The clock of the first slave station will be used as the reference clock.

[0086] 3. Local Clock, Initial Clock Offset, and Clock Drift. Each distributed slave station has a local clock that operates independently, using its local clock signal for timing. The slave station begins operation upon power-up. Each slave station's local clock has a difference (different initial values), so this difference with the reference clock is called the initial clock offset. During operation, due to the differences in the clock sources (crystal oscillators) of each slave station, the local clock also experiences clock drift (similar to the accumulated error in a clock), thus requiring clock drift compensation.

[0087] 4. Transmission delay. Data frames will have a certain delay when transmitted between slave stations, including internal processing delay (although EtherCAT signals are processed in real time by hardware, there is still a nanosecond-level delay) and physical connection delay (signal transmission delay). Therefore, compensation and correction are required to ensure the accuracy of the slave station clock.

[0088] 5. Master Clock. The master clock also has a timing function. During the initialization phase, the master clock sends its time to the reference clock slave (the first distributed slave) according to the system time format.

[0089] During reset, the slave MCU automatically reads the configuration information from the EEPROM.

[0090] In practical applications, after correcting the master clock of the EtherCAT master station according to the reference clock, the process further includes: the EtherCAT master station sending a broadcast command to the EtherCAT slave station to write data frames; based on the write data frames, the EtherCAT slave station writes its local clock into a first receiving time port and sends it back to the EtherCAT master station; during the backhaul process, the EtherCAT slave station writes its local clock into a second receiving time port, and the EtherCAT master station calculates the local offset time based on the local clock written into the first receiving time port; and calculates the delay of each EtherCAT slave station relative to the reference clock based on the local clock written into the first receiving time port and the local clock written into the second receiving time port.

[0091] Furthermore, the approach to configuring the synchronization clock is as follows: first, the master station sends and receives data; second, the time difference between the data and each slave station is calculated; and then the time is adjusted based on the time difference.

[0092] The specific process of distributed clock verification is as follows:

[0093] 1. When the master station sends a broadcast command to write a data frame, the slave station receives the frame (when Port0 receives the first bit of the data preamble), and writes the local clock into the parameter Receive time Port0, which is T1(n), where n is the slave station number, and so on.

[0094] 2. When the data frame is transmitted back (when Port2 receives the first bit of the data preamble), the local clock is written to the parameter Receive time Port1, and recorded as T2(n).

[0095] 3. The master station can calculate the local offset time (master station sending time - slave station recorded Receive time Port0) by reading the slave station's Receive time Port0, and obtain the initial offset time: Toffset = master station clock - local clock. Then, this value is written to the slave station's System Time offset register (remote write command).

[0096] 4. The master station can calculate the delay of each slave station relative to the reference clock (the first distributed clock slave station) based on the values ​​T1(n) and T2(n) of Receive time Port0 and Receive time Port1. The calculation formula is [T2(1)-T1(1)-(T2(n)-T1(n))] / 2. Here, it is assumed that the transmission time is uniform. The master station writes the delay time calculated by the master station into the System time transmission delay parameter in the slave station's register. Refer to Table 1, which is the local parameter table of the distributed clock.

[0097] Table 1

[0098]

[0099] The master station writes the configuration information into the slave station's onboard EEPROM via the IIC bus.

[0100] Figure 6 This diagram illustrates the time synchronization process; the time recording for the slave station is automatically completed by the hardware.

[0101] To quickly compensate for the initial clock deviation, the master station should send many ARMV / FRAM messages in independent data frames after measuring the transmission delay and offset compensation to complete the distributed clock initialization.

[0102] Subsequently, during the periodic operation phase, the reference clock can be read by periodically sending ARMV / FRAM message commands along with the process data, dynamically compensating for clock drift.

[0103] The period for sending clock synchronization data frames must meet the requirement that the slave clock drift is less than the maximum drift specified by the control application.

[0104] Step 302: Based on the configuration information, obtain the time-domain characteristics of the bridge vibration data at adjacent measurement points of each EtherCAT slave station; the time-domain characteristics include time-domain vibration waveform, spectrum, power spectrum, amplitude, and bridge deck tilt angle.

[0105] In practical applications, after the system is configured, the system is run. The main station software analyzes the vibration time and frequency to obtain the time and frequency characteristics of the vibration data of adjacent measurement points, which mainly include: time-domain vibration waveform, spectrum, power spectrum, amplitude, bridge deck tilt angle, etc.

[0106] Main station software – Vibration time-frequency analysis. Vibration measurement, calculation, and analysis.

[0107] (1) Select the slave station number that needs to be displayed and analyzed in real time on the interface. Data from unselected slave stations is saved directly as raw data without calculation or analysis to improve system efficiency.

[0108] (2) Data filtering, mainly using 16th order FIR filtering.

[0109] (3) Display of time-domain vibration waveform.

[0110] (4) Analysis of important parameters of time-domain vibration waveform, mainly including maximum value, minimum value, mean value and standard deviation.

[0111] (5) Frequency domain waveform display, i.e. spectrum and power spectrum display.

[0112] (6) Analysis of important parameters of spectrum and power spectrum, mainly including main frequency and its corresponding amplitude and power (level energy) ratio.

[0113] (7) Bridge deck inclination angle.

[0114] Step 303: Determine the propagation characteristics of the bridge vibration wave based on the time-domain characteristics; the propagation characteristics include propagation time, vibration waveform, and spectral waveform.

[0115] The main station software analyzes the propagation characteristics of bridge vibration waves based on the aforementioned time-frequency characteristics, and obtains the propagation characteristics of bridge vibration waves.

[0116] Main station software – Analysis of the propagation characteristics of bridge vibration waves.

[0117] Figure 7 This is a schematic diagram showing the specific location of the vibration sensor provided by the present invention, as shown below. Figure 7 As shown, assuming the vehicle causes vibration at position 1, the vibration waveform will propagate to positions 2 and 3. Similarly, if the vehicle causes vibration at position 2, the vibration waveform will propagate to positions 1 and 3.

[0118] In this invention, due to the configuration of distributed clocks for the EtherCAT slave stations (i.e., the vibration detectors at positions 1, 2, and 3 in the diagram above), synchronous sampling at positions 1, 2, and 3 is achieved. Therefore, there is a certain time difference between the vibration waveforms at positions 1, 2, and 3. Although the propagation attenuation amplitudes are different, the waveform shapes, frequencies, and power spectra are similar.

[0119] Analysis of key parameters of propagation characteristics.

[0120] (1) The propagation time, such as the time it takes for a vibration wave to propagate from position 1 to position 2. The time is proportional to the distance between position 1 and position 2.

[0121] (2) Correlation coefficient of time-domain vibration waveform. The correlation coefficient is a data in the range of [0 1]. The larger the data, the more similar the two waveforms are, and the better the bridge propagation characteristics are; and vice versa.

[0122] (3) Correlation coefficient of frequency domain waveform. The principle is the same as above.

[0123] Logical relationship: The premise of propagation characteristic analysis is synchronous sampling, and the premise of synchronous sampling is that the distributed clock is configured properly.

[0124] Since positions 1, 2, and 3 may be far apart, other methods cannot achieve this.

[0125] Based on the time-frequency characteristics of vibration data from adjacent measurement points, the propagation characteristics of bridge vibration waves are analyzed.

[0126] Step 304: Determine the current state of the bridge based on the propagation characteristics; the current state includes a normal state and a damaged state.

[0127] In practical applications, step 304 specifically includes: acquiring the propagation characteristics of the bridge under normal conditions; comparing the propagation characteristics of the bridge under normal conditions with the propagation characteristics of the monitored bridge vibration waves to generate a comparison difference; when the comparison difference exceeds a set difference threshold, determining that the current state of the bridge is a damaged state; when the comparison difference does not exceed the set difference threshold, determining that the current state of the bridge is a normal state.

[0128] The health status of the bridge can be determined based on the aforementioned time-frequency characteristics and the propagation characteristics of vibration waves.

[0129] The main approach to judging the health status of a bridge is "comparison," that is, comparing the real-time measurement and analysis results with the measurement and analysis results under normal conditions. If the difference exceeds a certain threshold, an alarm is triggered.

[0130] Typical judgment:

[0131] (1) The Z-axis amplitude of the bridge deck is very large and the X-circumference tilt angle of the bridge deck is very large. This may be due to a decrease in the load-bearing capacity of the bridge deck and the presence of overloaded vehicles on the bridge deck.

[0132] (2) The bridge deck Y-axis vibration is large and the bridge deck Y-axis tilt angle is large. This may be due to a decrease in the load-bearing capacity on one side of the bridge deck and an overloaded vehicle on one side of the bridge deck.

[0133] (3) Under normal circumstances, there are many cars on the bridge deck, and the time-domain vibration waveform and frequency-domain waveform are flat; when there are heavy trucks on the bridge deck, the waveform is steep and has a single peak.

[0134] (4) When there are many cars on the bridge surface, the time-domain vibration waveform and frequency-domain waveform are not flat and the waveform is steep.

[0135] (3) Under normal bridge conditions, the correlation coefficient between the vibration waveform and the frequency spectrum waveform at nearby measurement points is relatively large. Under abnormal bridge conditions, the correlation coefficient between the time-domain vibration waveform and the frequency-domain waveform at nearby measurement points decreases. If vehicle-related issues are ruled out, the problem is likely due to the internal structure of the bridge. Therefore, it is important to use the vibration wave propagation characteristics to make a judgment.

[0136] Example 3

[0137] An electronic device includes a memory and a processor, the memory storing a computer program and the processor running the computer program to enable the electronic device to perform the measurement method for multi-point synchronous measurement of bridge vibration as described above.

[0138] A computer-readable storage medium storing a computer program that, when executed by a processor, implements the measurement method for multi-point synchronous measurement of bridge vibration as described above.

[0139] The present invention has the following advantages:

[0140] (1) Using bus technology, wiring is simple and saves wiring costs.

[0141] If the bridge is short and there are few measurement points, only a small number of vibration sensors need to be installed, then the advantages of using bus technology are not obvious.

[0142] If the bridge is long, such as 5 kilometers or even longer, there will be many measurement points, requiring the installation of many vibration sensors, sometimes as many as dozens or even hundreds of vibration sensors. In this case, the advantages of using bus technology are obvious; otherwise, the wiring will be very complex and messy.

[0143] (2) Using bus technology, only one master station is needed, saving the cost of the master station and making detection convenient.

[0144] With the adoption of bus technology, no matter how many measurement points there are, only one master station is needed, saving master station costs. At the same time, it facilitates detection and centralized management, and technicians do not need to move around, thus improving detection efficiency.

[0145] (3) It adopts EtherCAT bus, which is fast and has a bandwidth of 100M.

[0146] Employing the EtherCAT bus, it boasts high speed and a bandwidth of up to 100 Mbps. On one hand, it allows for simultaneous measurement of data from multiple vibration sensors, facilitating the simultaneous detection of multiple measurement points. On the other hand, it enables the use of high-frequency vibration sensor data acquisition rates, which is beneficial for detecting the high-frequency characteristics of bridge vibrations.

[0147] (4) Using the EtherCAT bus and its clock synchronization technology, data from multiple vibration sensors can be acquired synchronously. (This is the most important and unique advantage.)

[0148] First, configure the EtherCAT synchronization clock. Second, detect the transmission delay between different slave stations. Then, use the transmission delay to correct the synchronization clock.

[0149] After configuration and modification, the EtherCAT slave station can synchronously acquire data from vibration sensors.

[0150] The synchronously acquired data has many important uses, allowing for the analysis of the propagation characteristics of vibration waves on bridges. By comparing this data with the propagation characteristics of vibration waves on bridges under normal conditions, a comprehensive and in-depth analysis of the bridge's health status can be achieved.

[0151] For long-span steel bridges, the propagation characteristics of vibration waves are a very important indicator, and are more effective than single-point vibration measurement data in analyzing the health status of the bridge.

[0152] If the vibration data from the vibration sensor is not collected synchronously, it is impossible to accurately analyze the propagation of vibration waves on the bridge.

[0153] (5) The measurement and analysis software on the main station has flexible functions.

[0154] You can select the measurement points where you want to measure and analyze the data.

[0155] If the selected measurement points are not continuous, vibration data of these measurement points can be collected separately, and vibration analysis can be performed on these measurement points separately.

[0156] If the selected measurement points are continuous, vibration data of these measurement points can be collected synchronously using clock synchronization technology. This allows for vibration analysis of each measurement point individually, as well as analysis of the propagation characteristics of vibration waves between these measurement points.

[0157] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. For the systems disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the descriptions are relatively simple; relevant parts can be referred to the method section.

[0158] This document uses specific examples to illustrate the principles and implementation methods of the present invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of the present invention. Furthermore, those skilled in the art will recognize that, based on the ideas of the present invention, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of the present invention.

Claims

1. A measurement system for multi-point synchronous measurement of bridge vibration, characterized in that, include: EtherCAT master and multiple EtherCAT slaves; Multiple EtherCAT slave stations are connected to each other, and the first EtherCAT slave station is connected to the EtherCAT master station; each EtherCAT slave station is connected to a vibration sensor, which is used to measure the vibration data of the bridge at each EtherCAT slave station measurement point; The EtherCAT master station synchronizes the clocks of the EtherCAT slave stations through the distributed clock synchronization mechanism of the EtherCAT protocol, controls the EtherCAT slave stations to synchronously measure the vibration data, and transmits the vibration data back to the EtherCAT master station via Ethernet in the EtherCAT protocol data format. The EtherCAT master station is used to monitor the vibration of the bridge at each measurement point of the EtherCAT slave station, analyze the propagation of bridge vibration waves between adjacent measurement points, and monitor the current state of the bridge. The current state includes a normal state and a damaged state. Based on the EtherCAT protocol, the clock of the first EtherCAT slave station with distributed clock function connected to the EtherCAT master station is used as the reference clock, and the clocks of the remaining EtherCAT slave stations are used as slave clocks. The master clock and slave clock of the EtherCAT master station are corrected according to the reference clock. The EtherCAT master station sends a broadcast command to the EtherCAT slave station to write data frames; Based on the write data frame, the EtherCAT slave station writes its local clock into the first receive time port and sends it back to the EtherCAT master station. During the backhaul process, the EtherCAT slave station writes its local clock into the second receive time port. The EtherCAT master station calculates the local offset time based on the local clock written to the first receiving time port; The delay of each EtherCAT slave relative to the reference clock is calculated based on the local clock written to the first receiving time port and the local clock written to the second receiving time port. The time-domain characteristics of the bridge vibration data at adjacent measurement points of each EtherCAT slave station are obtained, and the propagation characteristics of the bridge vibration wave are determined based on the time-domain characteristics. The time-domain characteristics include the time-domain vibration waveform, spectrum, power spectrum, amplitude, and bridge deck tilt angle. The propagation characteristics include propagation time, vibration waveform, and spectrum waveform.

2. The measurement system for multi-point synchronous measurement of bridge vibration according to claim 1, characterized in that, The EtherCAT slave station specifically includes: a master control chip, an EEPROM storage chip, an LCD / LED module and a button circuit, and a first Ethernet interface, a first network transformer, an EtherCAT control chip, a second network transformer and a second Ethernet interface connected in sequence. The main control chip is connected to the EtherCAT control chip, the vibration sensor, the EEPROM storage chip, the LCD / LED module, and the button circuit, respectively. The EtherCAT control chip and the main control chip communicate via a parallel I / O interface or an SPI interface; the EtherCAT control chip is used for EtherCAT bus control; the EEPROM storage chip and the EtherCAT control chip communicate via an IIC interface. The first Ethernet interface and the second Ethernet interface are RJ45 interfaces used to connect to the EtherCAT master station or an adjacent EtherCAT slave station; the first Ethernet interface is isolated from the EtherCAT control chip through the first network transformer, and the second Ethernet interface is isolated from the EtherCAT control chip through the second network transformer. The EEPROM storage chip is used to store the configuration file of the EtherCAT slave station itself; In the LCD / LED module, the LCD is used to display the text and graphics of the EtherCAT slave station itself, and the LED is used to display the working status and fault indication of the EtherCAT slave station itself. The button circuit is used to set the working mode of the EtherCAT slave station itself.

3. A method for simultaneously measuring bridge vibration at multiple points, characterized in that, The measurement method is applied to the multi-point synchronous measurement system for bridge vibration as described in any one of claims 1-2, and the measurement method includes: Configure the basic parameters of the EtherCAT slave station, configure the clock of the EtherCAT slave station based on the distributed clock synchronization mechanism of the EtherCAT protocol, synchronize the clocks of all EtherCAT slave stations and the EtherCAT master station, and write configuration information to the EtherCAT slave station; the basic parameters include manufacturer information and slave station description information; the configuration information includes basic parameters and synchronization clock; Based on the configuration information, the time-domain characteristics of the bridge vibration data at adjacent measurement points of each EtherCAT slave station are obtained; the time-domain characteristics include time-domain vibration waveform, spectrum, power spectrum, amplitude, and bridge deck tilt angle. The propagation characteristics of bridge vibration waves are determined based on the time-domain characteristics; the propagation characteristics include propagation time, vibration waveform, and spectral waveform. Determining the current state of the bridge based on the propagation characteristics specifically includes: Obtain the propagation characteristics of the bridge under normal conditions; By comparing the propagation characteristics of the bridge under normal conditions with the propagation characteristics of the monitored bridge vibration waves, a comparative difference is generated. When the difference exceeds a set difference threshold, the current state of the bridge is determined to be a damaged state. When the difference in comparison does not exceed the set difference threshold, the current state of the bridge is determined to be normal; the current state includes both normal state and damaged state.

4. The method for measuring bridge vibration synchronously at multiple points according to claim 3, characterized in that, Configure the clocks of EtherCAT slave stations based on the EtherCAT protocol, and synchronize the clocks of all EtherCAT slave stations and the EtherCAT master station, specifically including: Obtain the local clocks of the remaining EtherCAT slaves; The initial clock offset is determined based on the reference clock and the local clock; The clock drift amount is determined based on the local clock; The slave clock is compensated and corrected based on the initial clock offset and the clock drift.

5. An electronic device, characterized in that, It includes a memory and a processor, the memory being used to store a computer program, and the processor running the computer program to cause the electronic device to perform a measurement method for multi-point synchronous measurement of bridge vibration as described in any one of claims 3-4.

6. A computer-readable storage medium, characterized in that, It stores a computer program, which, when executed by a processor, implements the measurement method for multi-point synchronous measurement of bridge vibration as described in any one of claims 3-4.

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