CN115307666A - Variable frequency acquisition system and method of vibrating wire sensor - Google Patents
Variable frequency acquisition system and method of vibrating wire sensor Download PDFInfo
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- CN115307666A CN115307666A CN202210947081.0A CN202210947081A CN115307666A CN 115307666 A CN115307666 A CN 115307666A CN 202210947081 A CN202210947081 A CN 202210947081A CN 115307666 A CN115307666 A CN 115307666A
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Abstract
The invention relates to a frequency conversion acquisition system and method of a vibrating wire sensor. The invention calculates the smoothness of the vibrating wire sensor data and dynamically adjusts the acquisition interval of the vibrating wire sensor data according to the calculation result to form the vibrating wire sensor frequency conversion acquisition device based on frequency conversion acquisition.
Description
Technical Field
The invention belongs to the technical field of geological engineering detection, and particularly relates to a variable frequency acquisition system and method of a vibrating wire sensor.
Background
In the field of geological engineering detection and information technology, there are many factors inducing natural disasters such as collapse, landslide and dam break, in order to reduce the loss caused by disasters, monitoring and early warning are generally needed, and according to the difference of disaster inducing factors, objects which are monitored conventionally generally have displacement deformation, stress change, pore water pressure and the like. The basic principle of the vibrating string sensor is that a strained metal steel string is used as a resonant sensor of a sensing element, and the variation of the natural vibration frequency of the resonant sensor corresponds to the magnitude of the tensile force, so that strain, pressure, displacement and other sensors can be obtained by pertinently designing a mechanical structure, and the sensors can be widely applied to geological disaster monitoring due to the unique advantages of the sensors, such as strong severe weather resistance, high reliability, low power consumption and the like.
At present, in the field of geological engineering detection and information technology, frequency data output by different vibrating wire sensors correspond to numerical values of different physical quantities, when the vibrating wire sensors are applied to geological disaster monitoring, the frequency data output by the vibrating wire sensors can be directly used for research on geological disaster inducing factors after conversion, research results of the frequency data can be helpful for geological disaster early warning, and therefore data acquisition of the vibrating wire sensors is very important. The traditional method for acquiring data of the vibrating wire sensor is used for acquiring data at fixed time intervals, namely the acquisition method is fixed frequency, and the method has the following defects: 1. the whole data acquisition system always runs at a fixed frequency, and in order to obtain a more detailed geological disaster evolution process, the frequency of data acquisition is adjusted to be the maximum, so that a large amount of redundant data is generated, and the system storage capacity is increased. 2. For a large amount of redundant data generated by a fixed frequency acquisition method in a wireless communication network of a field local area networking, higher requirements are put forward on the transmission rate, the communication bandwidth and the like of a communication terminal, and the power consumption and the cost in the communication process are increased. 3. The excessive redundant data causes that the workload is increased by times when the disaster mechanism analysis is carried out at the later stage, which is not beneficial to carrying out the data analysis quickly and violates the emergency disaster relief principle.
Disclosure of Invention
The present invention aims to solve the above problems and provide a system and a method for frequency conversion acquisition of a vibrating wire sensor.
In order to achieve the purpose, the invention adopts the following technical scheme:
a variable frequency acquisition system for a vibrating wire sensor, comprising: the reading module is respectively connected with the embedded microcontroller and the vibrating wire sensor; the embedded microcontroller is used for driving the reading module to acquire sensing data obtained by the vibrating wire sensor according to the acquisition interval;
wherein; and the embedded microcontroller dynamically adjusts the sensing data acquisition interval according to the smoothness of the acquired sensing data.
Preferably, the smoothness of the collected sensing data is calculated as follows:
s is set as the data of the vibrating wire sensor acquired by the reading module at the current moment, S i For the output of data to the current reading module, i=1, 2, 3 …, if i data are collected in m time range, average change value
Comprises the following steps:
wherein, m is greater than 0,
setting j to be more than or equal to i within n time range, and setting j =1, 2 and 3 …, the average value of the data of the section is
Comprises the following steps:
wherein n is more than or equal to m and more than 0;
using mean change value
And average value
Obtaining smoothness results
Comprises the following steps:
preferably, the reading module provides an excitation signal for the vibrating wire sensor, the vibrating wire sensor outputs a vibration signal according to the excitation signal, the reading module performs analog-to-digital conversion, filtering processing, analysis and calculation and quality evaluation operations according to the vibration signal to obtain frequency data, meanwhile, the temperature sensor connected to the reading module is driven to obtain temperature data, and the reading module transmits the frequency data and the temperature data to the embedded microcontroller.
Preferably, the method further comprises the following steps: and the LoRa module is connected with the embedded microcontroller and is used for uploading the frequency data and the temperature data transmitted by the embedded microcontroller to the designated equipment in the local area network in a wireless communication mode.
Preferably, the embedded microcontroller drives the reading module to normally work and acquire the frequency data and the temperature data through commands.
Preferably, the method further comprises the following steps: temperature sensor, loRa module, electric quantity collection module, SD card, lithium cell group, the reading module with temperature sensor connects, embedded microcontroller is connected with loRa module, electric quantity collection module, SD card.
The invention also provides a variable frequency acquisition method of the vibrating wire sensor, which comprises the following steps:
s1, providing an excitation signal to a vibrating wire sensor by a reading module; the vibrating wire sensor outputs a vibration signal according to the excitation signal to obtain sensing data;
s2, the embedded microcontroller drives a reading module to acquire sensing data obtained by the vibrating wire sensor according to the acquisition interval; wherein; and the embedded microcontroller dynamically adjusts the sensing data acquisition interval according to the smoothness of the acquired sensing data.
Preferably, the smoothness of the collected sensing data is calculated as follows:
s is set as the data of the vibrating wire sensor acquired by the reading module at the current moment, S i For outputting data to the current reading module, i =1, 2, 3 …, i data are collected within m time range, and then average variation value is set
Comprises the following steps:
wherein, m is greater than 0,
setting j to be more than or equal to i within n time range, and setting j =1, 2 and 3 …, the average value of the data of the section is
Comprises the following steps:
wherein n is more than or equal to m and more than 0;
using mean change value
And average value
Obtaining smoothness results
Comprises the following steps:
the invention calculates the smoothness of the vibrating wire sensor data and dynamically adjusts the acquisition interval of the vibrating wire sensor data according to the calculation result to form a vibrating wire sensor variable frequency acquisition system based on variable frequency acquisition.
Drawings
FIG. 1 is a block diagram of the acquisition system of the present invention;
FIG. 2 is a schematic diagram of the operation of the reading module of the present invention;
FIG. 3 is a schematic diagram of the frequency conversion acquisition principle of the present invention;
FIG. 4 is a schematic diagram comparing different acquisition methods of the present invention;
FIG. 5 is a flowchart of the embedded program of the present invention.
Detailed Description
The invention will be further described with reference to the accompanying drawings in which:
example 1:
as shown in fig. 1, the present invention provides a frequency conversion collecting system of a vibrating wire sensor, comprising: the device comprises a vibrating wire sensor, a reading module, a temperature sensor, a LoRa module, an electric quantity acquisition module, an embedded microcontroller, an SD card and a lithium battery pack; the vibrating wire sensor is connected with the reading module, the reading module is connected with the temperature sensor, the embedded microcontroller is connected with the reading module, the LoRa module, the electric quantity acquisition module and the SD card, and the lithium battery pack is used for providing a power supply. When the vibration wire sensor works, the reading module provides excitation for the vibration wire sensor, the vibration wire sensor starts to vibrate forcibly after receiving an excitation signal, the vibration wire sensor starts to vibrate automatically after a short time, and the vibration wire sensor continuously outputs a vibration signal to the outside in the whole process. After the reading module gives an excitation signal to the vibrating wire sensor, the vibrating wire sensor outputs a vibration signal, the reading module performs corresponding analog-to-digital conversion, filtering processing, analysis calculation and quality evaluation operations after acquiring the vibration signal to finally obtain frequency data, and simultaneously drives an external temperature sensor connected to the reading module to obtain temperature data, and the frequency data and the temperature data are transmitted to the embedded microcontroller in a serial port communication mode by the reading module after the acquisition is completed. The power supply of the reading module can be controlled by the embedded microcontroller, and the power supply of the temperature sensor is provided by the reading module. The LoRa module and the embedded microcontroller are communicated in a serial port communication mode, data which needs to be transmitted by the embedded microcontroller can be uploaded to designated equipment in a local area network in a wireless communication mode, and a power supply of the embedded microcontroller can be controlled by the embedded microcontroller. The electric quantity acquisition module is used for acquiring system power supply voltage, can indirectly reflect the electric quantity of the lithium battery pack, and outputs an analog signal. The SD card is used for storing data. The temperature sensor is used for acquiring the ambient temperature. The embedded microcontroller is connected with the reading module, and aims to issue a corresponding command to drive the reading module to normally work, frequency data and temperature data can be acquired through the command, communication between the two modules is carried out in a serial port communication mode, and the embedded microcontroller can control a power supply of the reading module through GPIO. The purpose of the connection of the embedded microcontroller and the LoRa module is to perform data interaction with the central node, such as data uploading and configuration updating operation. The purpose that embedded microcontroller and electric quantity collection module are connected is in obtaining electric quantity information, and the signal access of electric quantity collection module output is to embedded microcontroller's on-chip ADC interface, and embedded microcontroller accessible GPIO controls the power of loRa module. The embedded microcontroller is connected with the SD card for storing sensor data and equipment running logs, and the communication between the SD card and the embedded microcontroller adopts an SPI protocol. A variable frequency acquisition algorithm is burnt in the embedded microcontroller, and the acquisition interval of frequency data can be dynamically adjusted according to the smoothness of the acquired data.
After the system is powered on, the embedded microcontroller performs system initialization, including initialization operations of on-chip resources, system peripherals and the like, and meanwhile, the reading module and the LoRa module can also perform self initialization operations after being powered on and operated under the control of the embedded microcontroller, the initialization of the LoRa module mainly comprises operations of hardware self-checking, on-chip resources and the like, and the initialization of the reading module comprises operations of vibrating wire sensor connection state detection, default parameter configuration and the like. After the system completes initialization under the guidance of the embedded microcontroller, the embedded microcontroller acquires sensing data obtained by the vibrating wire sensor through the command driving reading module according to a preset acquisition interval.
The working flow of the reading module is as shown in fig. 2, and after the reading module obtains a corresponding command through the digital interface, corresponding operation is performed according to the command. After the reading module acquires a data acquisition command, the reading module excites and outputs the vibrating wire sensor, the excitation comprises two types of high-voltage pulse and low-voltage sweep frequency, the vibrating wire sensor receives the excitation and outputs a response signal according to the working principle of the vibrating wire sensor, if high-voltage excitation is adopted, the signal comprises two parts of forced vibration and autonomous vibration, the forced vibration signal reading module is default and can be omitted, analog-to-digital conversion is only carried out on the autonomous vibration signal, namely data acquisition is carried out, after the acquisition is finished, analysis and calculation are carried out on a section of acquired data in the reading module, the analysis and calculation mainly comprises two aspects of frequency calculation and quality evaluation, after the calculation is finished, a frequency calculation result and a quality evaluation result are output to the embedded microcontroller through a digital interface, and meanwhile, the reading module enters an idle state to wait for the next data acquisition command.
In the data acquisition process, a large amount of redundant data can be brought by acquiring the vibrating wire sensor data at equal intervals, and in order to reduce the data redundancy, the data acquisition principle adopted by the invention is shown in fig. 3. After the system is powered on and operated, firstly, the sensor data is collected according to the initialization interval time, smoothness calculation is carried out after a certain amount of data is collected, the data collection interval is dynamically adjusted according to the obtained smoothness calculation result, when the smoothness calculation result exceeds a set threshold value, the system can also carry out data collection according to the minimum interval, and finally, a data set is formed and smoothness calculation is carried out next time according to the data set.
The calculation of smoothness is the core of the whole frequency conversion acquisition algorithm. Assuming that the vibrating wire sensor data acquired by the reading module at the current moment is S, the data output by the reading module at the current moment can be S for the digital signal with the sequence property i Where i =1, 2, 3 …. To know the current data S i Can be represented by the difference between the current data and the previous data, i.e. | S i -S i-1 Where i =1, 2, 3 …, although this method can already describe the fluctuation situation of the data before and after, the response sensitivity is too high and no trend can be seen, so further improvement and optimization are required. The data averaging method can obtain the fluctuation condition of the data and can further see the trend of the data, so that the reading can be aimed atA certain segment of data output by the module is used to obtain the average variation value of the data, wherein m (m) is assumed>0, unit is second) time range, the average change value of the data is obtained
Can be represented by the following formula:
although smoothness can be determined from the average change value by the above formula, the data results obtained in this case show a large difference according to the vibrating wire sensors used, because the units of the vibrating wire sensors of different physical quantities are usually different. In order to be compatible with more vibrating wire sensors and avoid complicated program upgrading operation after the types of the vibrating wire sensors are changed, another section of data is introduced, j data are collected within the time range of n (n is more than or equal to m and more than 0, and the unit is second), and the average value of the section of data is assumed to be more than or equal to i, j =1, 2 and 3 …
Can be represented by the following formula:
mean value of
Mean change value of binding data
Smoothness can be locked to a fixed interval range, so that the average change value of data is utilized
And average value
More reasonable smoothness results can be obtained
Specifically, the formula is shown as follows:
in that
In the calculation formula (2), can be
Is understood as the average change value of data obtained by a sliding interval changed by updating acquired data, and the size of a data set of the average change value is always smaller than that of the data set
Number of data sets owned, therefore
Is in a variation interval greater than 0 and less than 1, and it is also noted here that
The interval (2) can also be varied in a sliding manner, but the size of the data set must be ensured to be larger than
Owned data set size.
After smoothness of the newly acquired data is obtained, different acquisition time intervals can be corresponded according to the smoothness. Dividing the acquisition interval time of the vibrating wire sensor data according to the needs of the vibrating wire sensor data, for example, if 10 acquisition interval grades are needed at present, and the interval time of the minimum acquisition interval is 2 seconds, the value range of the smoothness is
And the smoothness is 0.1, the acquisition interval is 20 seconds/time, the acquisition interval is 18 seconds/time when the smoothness is 0.2, other results are analogized, and the specific interval time range can be adjusted according to the needs of the user.
The smoothness and the change degree of the data have a certain corresponding relation, the greater the smoothness, the greater the change degree of the data, and at the moment, the acquisition density of the data needs to be increased, namely, the acquisition interval is shortened; the smaller the smoothness, the smaller the degree of data change, and the data acquisition density needs to be reduced, i.e. the time interval for data acquisition needs to be increased. The pair of the method for acquiring the vibrating wire sensor data in a frequency conversion manner according to smoothness and the conventional fixed frequency acquisition method is shown in fig. 4, the conventional fixed frequency acquisition method described in fig. 4 (a) needs to work according to a minimum data acquisition interval in order to obtain the geological disaster evolution details, the frequency conversion acquisition method described in fig. 4 (b) can dynamically adjust a time interval according to the change degree of current data, and can set a threshold value, and when the dynamically adjusted time interval is smaller than the threshold value, the minimum data acquisition interval can be directly sampled to work to obtain the geological disaster evolution details. It can also be seen from fig. 4 that the sampling frequency conversion acquisition method has less data volume, further reduces redundant data, reduces the overall operation power consumption of the system, reduces the performance requirements of the wireless communication module, and is advantageous in data acquisition of the vibrating wire sensor.
The embedded program flow of the invention is shown in fig. 5, after the system is powered on, firstly, initialization operation is carried out, initialization operation of on-chip resources, peripheral equipment, smoothness judgment intervals and the like is required to be completed in the initialization process, smoothness calculation and judgment are carried out according to vibration wire sensor data obtained by latest acquisition, if smoothness is abnormal, the time interval of data acquisition is adjusted, if the time interval is too long, timed dormancy is carried out, sensor data acquisition is continued after the time is up, if the time interval does not exceed the dormancy time interval threshold, sensor data acquisition is directly carried out without dormancy, and smoothness abnormity judgment is continued after the acquisition is completed; if the smoothness is not abnormal, judging whether the current data set exceeds the set size, if not, continuing to acquire the sensor data, if so, starting to acquire the electric quantity data, formatting the acquired electric quantity data and the sensor data in the data set together, writing the data into the SD card for backup after formatting is finished, and simultaneously starting the LoRa module to wirelessly transmit the data to a specified device in the local area network, thereby finishing a cycle.
Example 2:
the invention also provides a variable frequency acquisition method of the vibrating wire sensor, which comprises the following steps:
s1, providing an excitation signal to a vibrating wire sensor by a reading module; the vibrating wire sensor outputs a vibration signal according to the excitation signal to obtain sensing data;
s2, the embedded microcontroller drives a reading module to acquire sensing data obtained by the vibrating wire sensor according to the acquisition interval; wherein; and the embedded microcontroller dynamically adjusts the sensing data acquisition interval according to the smoothness of the acquired sensing data.
As an implementation manner of this embodiment, the smoothness of the collected sensing data is calculated as follows:
s is set as the data of the vibrating wire sensor acquired by the reading module at the current moment, S i In order to output data to the current reading module, i =1, 2 and 3 …, i data are collected in m time range, and then average change value is obtained
Comprises the following steps:
wherein, m is greater than 0,
setting j to be more than or equal to i within n time range, and setting j =1, 2 and 3 …, the average value of the data of the section is
Comprises the following steps:
wherein n is more than or equal to m and more than 0;
using mean change value
And average value
Obtaining smoothness results
Comprises the following steps:
the foregoing shows and describes the general principles and features of the present invention, together with the advantages thereof. It will be understood by those skilled in the art that the present invention is not limited to the embodiments described above, which are described in the specification and illustrated only to illustrate the principle of the present invention, but that various changes and modifications may be made therein without departing from the spirit and scope of the present invention, which fall within the scope of the invention as claimed. The scope of the invention is defined by the appended claims and equivalents thereof.
Claims (8)
1. A frequency conversion collection system of vibrating wire sensor, characterized by includes: the reading module is respectively connected with the embedded microcontroller and the vibrating wire sensor; the embedded microcontroller is used for driving the reading module to acquire sensing data obtained by the vibrating wire sensor according to the acquisition interval;
wherein; and the embedded microcontroller dynamically adjusts the sensing data acquisition interval according to the smoothness of the acquired sensing data.
2. The variable frequency acquisition system for vibrating wire sensors according to claim 1 wherein the smoothness of the acquired sensory data is calculated as follows:
s is set as the data of the vibrating wire sensor acquired by the reading module at the current moment, S i For outputting data to the current reading module, i =1, 2, 3 …, i data are collected within m time range, and then average variation value is set
Comprises the following steps:
wherein, m is greater than 0,
setting j to be more than or equal to i within n time range, and setting j =1, 2 and 3 …, the average value of the data of the section is
Comprises the following steps:
wherein n is more than or equal to m and more than 0;
using mean change value
And average value
Obtaining smoothness results
Comprises the following steps:
3. the variable frequency acquisition system of the vibrating wire sensor as claimed in claim 2, wherein the reading module provides an excitation signal to the vibrating wire sensor, the vibrating wire sensor outputs a vibration signal according to the excitation signal, the reading module performs analog-to-digital conversion, filtering processing, analysis and calculation, and quality evaluation operations according to the vibration signal to obtain frequency data, and simultaneously drives the temperature sensor connected to the reading module to obtain temperature data, and the reading module transmits the frequency data and the temperature data to the embedded microcontroller.
4. The variable frequency acquisition system for vibrating wire sensors according to claim 3, further comprising: and the LoRa module is connected with the embedded microcontroller and is used for uploading the frequency data and the temperature data transmitted by the embedded microcontroller to designated equipment in a local area network in a wireless communication mode.
5. The variable frequency acquisition system for vibrating wire sensors according to claim 4 wherein said embedded microcontroller commands the drive reading module to operate properly and acquire said frequency and temperature data.
6. The variable frequency acquisition system for vibrating wire sensors according to claim 5 further comprising: temperature sensor, loRa module, electric quantity collection module, SD card, lithium cell group, the reading module with temperature sensor connects, embedded microcontroller is connected with loRa module, electric quantity collection module, SD card.
7. A frequency conversion acquisition method of a vibrating wire sensor is characterized by comprising the following steps:
s1, providing an excitation signal to a vibrating wire sensor by a reading module; the vibrating wire sensor outputs a vibration signal according to the excitation signal to obtain sensing data;
s2, the embedded microcontroller drives a reading module to acquire sensing data obtained by the vibrating wire sensor according to the acquisition interval; wherein; and the embedded microcontroller dynamically adjusts the sensing data acquisition interval according to the smoothness of the acquired sensing data.
8. A method for variable frequency acquisition of vibrating wire sensors as in claim 7 wherein the smoothness of the acquired sensed data is calculated as follows:
s is set as the data of the vibrating wire sensor acquired by the reading module at the current moment, S i For outputting data to the current reading module, i =1, 2, 3 …, i data are collected within m time range, and then average variation value is set
Comprises the following steps:
wherein, m is greater than 0,
setting j to be more than or equal to i within n time range, and setting j =1, 2 and 3 …, the average value of the data of the section is
Comprises the following steps:
wherein n is more than or equal to m and more than 0;
using mean change value
And average value
To obtain a smooth knotFruit
Comprises the following steps:
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| CN116612572A (en) * | 2023-06-14 | 2023-08-18 | 厦门万安智能有限公司 | Building access control management system |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN116612572A (en) * | 2023-06-14 | 2023-08-18 | 厦门万安智能有限公司 | Building access control management system |
| CN116612572B (en) * | 2023-06-14 | 2024-03-19 | 厦门万安智能有限公司 | Building access control management system |
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