Data averaging algorithm for pretightening force electromagnetic ultrasonic measurement

Abstract

The invention discloses a data averaging algorithm for pretightening force electromagnetic ultrasonic measurement, which comprises the following steps of: (1) converting Nth frame echo data received by an electromagnetic ultrasonic probe (i) into digital signal data D through an amplifier and an analog-to-digital converter (d), representing the digital signal data D as # imgabs0 #, representing the number of data points received by each frame of probe, and representing the number of data points received by each frame of probe; the # imgabs1 # is decomposed into effective echo data # imgabs2 # and random noise # imgabs3 #, and digital signal data # imgabs4 # are obtained; (2) dividing the historical accumulated data A stored in the storage space (a) into two paths of data; according to the data averaging algorithm, only the current frame echo data and the historical accumulated data need to be processed each time, the historical accumulated data received by the electromagnetic ultrasonic probe only needs to be stored once in the storage space, and the average data of electromagnetic ultrasonic measurement can be output after new frame echo data are received each time, so that the calculation amount is greatly reduced, and the calculation efficiency is improved. The data processing speed is improved, the repetition frequency of data output is reduced, the signal-to-noise ratio is higher, and pretightening force measurement is facilitated.

Description

Technical Field

[0001] The invention relates to the technical field of electromagnetic ultrasonic measurement of preload force, and in particular to a data averaging algorithm for electromagnetic ultrasonic measurement of preload force. Background Art

[0002] Bolt preload is the preload along the bolt axis generated between the bolt and the connected part under the action of the tightening torque during the bolt tightening process. For a specific bolt, the magnitude of its preload is related to the tightening torque of the bolt, the friction between the bolt and the nut, and the friction between the nut and the connected part.

[0003] The control of bolt preload can improve the reliability, anti-loosening ability and fatigue strength of bolts, and enhance the tightness and rigidity of connections. In fact, a large number of tests and use experience have proved that higher preload is beneficial to the reliability of connections and the life of the connections, especially for connections with sealing requirements. However, excessive preload, if improperly controlled or accidentally overloaded, will often lead to failure of the connection. Therefore, it is very important to accurately determine the preload of the bolts.

[0004] The preload force measurement requires high precision, and the data accuracy can reach 1ns, that is, the electromagnetic ultrasonic data collected by the analog-to-digital converter (ADC) has an accuracy of 1ns, resulting in a very large amount of data received each time by the electromagnetic ultrasound. If the storage space needs to save the huge amount of electromagnetic ultrasonic raw data received multiple times, the storage space requirements are very high, and it takes longer to process the huge amount of data, increasing the repetition frequency of data output, which will affect the real-time and response speed of the system. In addition, high-capacity storage devices are usually expensive and will increase the overall cost of the system. Summary of the invention

[0005] The problem to be solved by the present invention is to provide a data averaging algorithm for electromagnetic ultrasonic measurement of preload force, which reduces the storage space requirement, reduces the data processing time, reduces the repetition frequency of data output, and improves the real-time performance and response speed of the system.

[0006] In order to solve the above technical problems, the technical solution adopted by the present invention is as follows: A data averaging algorithm for electromagnetic ultrasonic measurement of preload force, characterized by comprising the following steps: Step (1) converts the Nth frame echo data received by the electromagnetic ultrasonic probe (i) into digital signal data D through an amplifier and an analog-to-digital converter (d). The digital signal data D is expressed as , k represents the number of data points received by the probe per frame, and then Decompose into effective echo data and random noise , get digital signal data ; Step (2) The historical accumulated data A stored in the storage space (a) is divided into two data paths: The first data path is to read the historical accumulated data A from the storage space (a), and then pass the historical accumulated data A through the divider (b) through the Nth input to obtain the intermediate data ; The second data path is to directly read the historical accumulated data A from the storage space (a); Step (3) The historical accumulated data A obtained from the second data path and the intermediate data B obtained from the first data path are calculated by the subtractor (c) to obtain the historical data ; Step (4) uses the Nth input to calculate the digital signal data D in step (1) through the divider (k) to obtain the new data ; Step (5) The historical data C in step (3) and the new data K in step (4) are calculated by adder (e) to obtain the average data ; Step (6) outputs the average data E as the measurement result; at the same time, the average data E is saved again to the storage space (a), and the original historical accumulated data A is overwritten, so that the storage space (a) stores the new historical accumulated data A, and the new historical accumulated data A is used to recalculate the average with the next frame echo data according to steps (1) to (5).

[0007] In the above step (2), the divider (b) performs a division operation to calculate the intermediate data B, thereby reducing the complexity of subsequent calculations.

[0008] The above step (3) performs a subtraction operation through a subtractor (c), which reduces the amount of data that needs to be processed each time and improves the calculation speed.

[0009] The above step (4) performs a division operation through the divider (k) to ensure the accuracy of the new data K.

[0010] The above step (5) performs an addition operation through the adder (e) to update the average data in real time, ensuring that the average data E output each time is real-time and accurate.

[0011] In the above step (2), when the system is initialized, the historical accumulated data A in the storage space (a) is 0, that is, A = 0. This is because the system has no historical data when it is initialized, so the data in the storage space (a) is empty or initialized to 0, which can ensure that there is no interference from any historical data when the system starts working.

[0012] Compared with the prior art, the present invention has the following advantages: The data averaging algorithm of the present invention only needs to process the current frame echo data and historical accumulated data each time, and the storage space only needs to save the historical accumulated data received by the electromagnetic ultrasonic probe once, and each time after receiving new frame echo data, the average data of the electromagnetic ultrasonic measurement can be output, which greatly reduces the amount of calculation, significantly improves the data processing speed, reduces the repetition frequency of data output, has a higher signal-to-noise ratio, and is conducive to preload force measurement. In addition, since the storage space requirement is reduced, the present invention can use a smaller capacity storage device to reduce storage costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 It is a schematic diagram of an algorithm flow of an embodiment of the present invention. DETAILED DESCRIPTION

[0014] The present invention is described in detail below with reference to the accompanying drawings and specific embodiments.

[0015] like Figure 1 As shown, the data averaging algorithm for the electromagnetic ultrasonic measurement of the preload force in this embodiment includes the following steps: Step (1) converts the Nth frame echo data received by the electromagnetic ultrasonic probe (i) into digital signal data D through an amplifier and an analog-to-digital converter (d). The digital signal data D is expressed as , k represents the number of data points received by the probe per frame, and then Decompose into effective echo data and random noise , get digital signal data ; Step (2) The historical accumulated data A stored in the storage space (a) is divided into two data paths: The first data path is to read the historical accumulated data A from the storage space (a), and then pass the historical accumulated data A through the divider (b) through the Nth input to obtain the intermediate data ; The second data path is to directly read the historical accumulated data A from the storage space (a); Step (3) The historical accumulated data A obtained from the second data path and the intermediate data B obtained from the first data path are calculated by the subtractor (c) to obtain the historical data ; Step (4) uses the Nth input to calculate the digital signal data D in step (1) through the divider (k) to obtain the new data ; Step (5) The historical data C in step (3) and the new data K in step (4) are calculated by adder (e) to obtain the average data ; Step (6) outputs the average data E as the measurement result; at the same time, the average data E is saved again to the storage space (a), and the original historical accumulated data A is overwritten, so that the storage space (a) stores the new historical accumulated data A, and the new historical accumulated data A is used to recalculate the average with the next frame echo data according to steps (1) to (5).

[0016] In the above step (2), the divider (b) performs a division operation to calculate the intermediate data B, thereby reducing the complexity of subsequent calculations.

[0017] The above step (3) performs a subtraction operation through a subtractor (c), which reduces the amount of data that needs to be processed each time and improves the calculation speed.

[0018] The above step (4) performs a division operation through the divider (k) to ensure the accuracy of the new data K.

[0019] The above step (5) performs an addition operation through the adder (e) to update the average data in real time, ensuring that the average data E output each time is real-time and accurate.

[0020] In step (2), when the system is initialized, the historical accumulated data A in the storage space (a) is 0, that is, A = 0. This is because the system has no historical data when it is initialized, so the data in the storage space (a) is empty or initialized to 0, which can ensure that there is no interference from any historical data when the system starts working.

[0021] In step (3), after the system is initialized, the first frame echo data received by the electromagnetic ultrasonic probe (i) for the first time is converted into digital signal data D through the amplifier and analog-to-digital converter (d) to obtain digital signal data After the system is initialized, when the historical accumulated data A in the storage space (a) is 0 and N=1, the average data in step (6) Therefore, after the first input, that is, when N=1, the valid echo data in the first frame echo data is , and its random noise is .

[0022] In step (3), when the electromagnetic ultrasonic probe (i) receives the second frame echo data for the second time, it is converted into digital signal data D through the amplifier and analog-to-digital converter (d) to obtain digital signal data At this time, the historical accumulated data A in the storage space (a) is the average data stored in the process of receiving the first frame echo data for the first time, that is, , when N=2, the average data in step (6) is Since the valid echo data in the frame echo data is , the echo data of each frame is close to the same, and in general, the effective echo data are basically the same, that is, , the formula for the above average data is simplified to .

[0023] Therefore, after the second input, that is, when N=2, the valid echo data in the second frame echo data is still , and its random noise is .

[0024] In step (3), when the third frame echo data received by the electromagnetic ultrasonic probe (i) for the third time is converted into digital signal data D through the amplifier and analog-to-digital converter (d), the digital signal data D is obtained. At this time, the historical accumulated data A in the storage space (a) is the average data stored in the process of receiving the second frame echo data for the second time, that is, , when N=3, the average data in step (6) is Since the valid echo data in the frame echo data is , the echo data of each frame is close to the same, and in general, the effective echo data are basically the same, that is, , the formula for average data is simplified to Therefore, after the third input, that is, when N=3, the valid echo data in the third frame echo data is still , and its random noise is .

[0025] Of course, N can be 4, 5, ..., 100, ..., and the valid echo data in the Nth frame echo data is still , and its random noise will not be listed and calculated here one by one.

[0026] Assume that the random noise in each frame echo data are independent and identically distributed, with a mean of 0 and a variance of We can calculate the variance of these random noises to compare their magnitudes.

[0027] When N=1, the variance of random noise is .

[0028] When N=2, the variance of random noise is .

[0029] When N=3, the variance of random noise is .

[0030] By comparing these variances, we can see that ,It can be seen that with the increase of N inputs, the variance of random noise gradually decreases, which indicates that the influence of random noise also gradually decreases, which means that with the increase of N, the proportion of effective signals in the average data increases, while the proportion of random noise decreases, thereby improving the signal-to-noise ratio of the data.

[0031] In addition, it should be noted that the names of the various parts of the specific embodiments described in this specification may be different, and any equivalent or simple changes made based on the structure, features and principles described in the patent concept of the present invention are included in the protection scope of the patent of the present invention. The technicians in the technical field of the present invention can make various modifications or supplements to the specific embodiments described or replace them in a similar manner, as long as they do not deviate from the structure of the present invention or exceed the scope defined by the claims, they should all fall within the protection scope of the present invention.

Claims

1. A data averaging algorithm for electromagnetic ultrasonic measurement of preload force, characterized in that The steps include: Step (1) converts the Nth frame echo data received by the electromagnetic ultrasonic probe (i) into digital signal data D through an amplifier and an analog-to-digital converter (d). The digital signal data D is expressed as , k represents the number of data points received by the probe per frame, and then Decompose into effective echo data and random noise , get digital signal data ; Step (2) The historical accumulated data A stored in the storage space (a) is divided into two data paths: The first data path is to read the historical accumulated data A from the storage space (a), and then pass the historical accumulated data A through the divider (b) through the Nth input to obtain the intermediate data ; The second data path is to directly read the historical accumulated data A from the storage space (a); Step (3) The historical accumulated data A obtained from the second data path and the intermediate data B obtained from the first data path are calculated by the subtractor (c) to obtain the historical data ; Step (4) uses the Nth input to calculate the digital signal data D in step (1) through the divider (k) to obtain the new data ; Step (5) The historical data C in step (3) and the new data K in step (4) are calculated by adder (e) to obtain the average data ; Step (6) outputs the average data E as the measurement result; at the same time, the average data E is saved again to the storage space (a), and the original historical accumulated data A is overwritten, so that the storage space (a) stores the new historical accumulated data A, and the new historical accumulated data A is used to recalculate the average with the next frame echo data according to steps (1) to (5).

Images