CN111912903A - A self-powered ultrasonic guided wave rail broken real-time detection system and positioning method - Google Patents

Abstract

The invention discloses a self-powered ultrasonic guided wave broken rail real-time detection system, comprising: an ultrasonic guided wave sending module, an ultrasonic guided wave receiving module, a communication module, a terminal and a self-powered module. The invention solves the problem of the existing ultrasonic guided wave The problem of unstable power supply in the real-time rail break detection system ensures the reliability of the power supply of the railway site monitoring equipment, and further improves the accuracy of rail break location detection. The invention also discloses a method for detecting track breakage. Based on the mechanism of transmitting and receiving at the same end at the same end, the Kasami sequence is first used to encode the transmitted ultrasonic guided wave signal, then the decoding judgment is performed, and finally the decoded signal is obtained. Envelope and calculate the time corresponding to the peak value of the envelope, so as to obtain the specific position of the track break and complete the track break positioning detection. The present invention greatly improves the track break positioning accuracy, thereby improving the reliability and detection accuracy of the ultrasonic guided wave track break detection system. .

Description

A self-powered ultrasonic guided wave rail broken real-time detection system and positioning method

technical field

The invention belongs to the technical field of non-destructive testing, relates to a self-powered ultrasonic guided wave real-time detection system for rail broken, and also relates to a broken rail positioning detection method.

Background technique

With the rapid economic development, the trend of high-speed railway passenger transportation and heavy-duty freight transportation has become more and more obvious. At the same time, high-speed railways have developed rapidly, and seamless long-gauge lines have been widely used. In the railway transportation system, the rails play the role of supporting the train and guiding the wheels to move forward. In order to ensure the safety of train operation, new requirements are put forward for the detection efficiency and detection accuracy of rail damage or fracture state. At present, the existing detection methods mainly include manual inspection, hand-push ultrasonic flaw detection trolley, large-scale rail flaw detection vehicle and track circuit. Except for the track circuit, the rest of the above methods belong to offline detection, but the track circuit is expensive. , high false alarm rate and not suitable for installation in wet road sections. However, in recent years, ultrasonic guided wave technology has been widely used due to its advantages of low detection frequency, long detection distance and large coverage. It is especially suitable for damage or fracture detection of long-distance structures such as pipes and rails. In order to detect rail damage or fracture status online in real time, researchers have developed a real-time detection system for rail breakage based on ultrasonic guided waves. However, the power supply, low signal-to-noise ratio and positioning accuracy of the detection system have become important factors affecting the reliability and detection accuracy of the system. . At present, the power supply of outdoor monitoring equipment on railway sites usually relies on photovoltaic power generation, but the conversion efficiency of solar energy is low and is greatly affected by weather conditions, especially in mountainous areas, the effective lighting time is only a few hours. In order to ensure the stability of the power supply of the system, a larger area of solar panels is required, resulting in a higher cost of the power supply system, which will limit the industrial application of the monitoring system to a certain extent. For the problem of low signal-to-noise ratio, the currently commonly used methods mainly include increasing the transmit power at the transmitting end and performing dispersion compensation at the receiving end. Limited by the excitation voltage peak value of the piezoelectric transducer, the increase in transmit power is also limited. Even if the dispersion is completely eliminated, the ultrasonic guided wave distance resolution still cannot meet the high-precision track break or damage location using the pulse echo method.

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide a self-powered ultrasonic guided wave real-time rail fault detection system, which solves the problem of unstable power supply in the existing ultrasonic guided wave real-time rail fault detection system.

Another object of the present invention is to provide a method for locating and detecting a broken rail, which can accurately measure the propagation time of the ultrasonic guided wave signal and improve the positioning accuracy of the broken rail.

The first technical solution adopted by the present invention is a self-powered ultrasonic guided wave real-time detection system for rail breakage, comprising:

The ultrasonic guided wave sending module is a transmitting node with vibration energy collection function, which is used to transmit ultrasonic guided wave signals;

The ultrasonic guided wave receiving module is a receiving node with vibration energy collection function, which is used to receive ultrasonic guided wave signals;

The communication module is used to send the track break information to the cloud server, and the track break information is judged and processed by the ultrasonic guided wave receiving module;

The terminal, connected to the cloud server, is used to receive track break information;

The self-powered module is used to provide electric power for the ultrasonic guided wave sending module, the ultrasonic guided wave receiving module and the communication module.

The first technical solution of the present invention is also characterized in that,

The ultrasonic guided wave sending module and the ultrasonic guided wave receiving module are alternately arranged with 1km as a detection interval, and the ultrasonic guided wave sending module or the ultrasonic guided wave receiving module located at one end of the alternate arrangement is connected to the communication module.

The ultrasonic guided wave sending module includes a coding excitation circuit and a communication interface circuit a that are connected together, and the communication interface circuit a is respectively connected with a piezoelectric transducer a with a vibration energy collection function, and an NBIOT wireless communication module a with a positioning function. The electrical transducer a is fixed on the track to be detected;

The ultrasonic guided wave receiving module includes a signal processing circuit and a communication interface circuit b that are connected together. The communication interface circuit b is respectively connected with a piezoelectric transducer b with a vibration energy collection function, and an NBIOT wireless communication module b with a positioning function. The electrical transducer b is fixed on the track to be detected.

The communication module includes a communication interface circuit c and an NBIOT communication module connected together, and the communication interface circuit c is connected with the communication interface circuit a or the communication interface circuit b.

The self-supply module includes a wind-solar hybrid power generation module and a rail vibration power generation module. The wind-solar hybrid power generation module and the rail vibration power generation module are all connected to the AC-DC power conversion module, and the AC-DC power conversion module is connected to the communication interface circuit a and the communication interface circuit b respectively. connect.

The second technical solution adopted by the present invention is a method for positioning and detecting a track breakage, which uses the self-powered ultrasonic guided wave track breakage real-time detection system of the first technical solution of the present invention to perform positioning detection, and transmits the same end based on the same end. The receiving mechanism firstly uses the Kasami sequence to encode the transmitted ultrasonic guided wave signal, then decodes and judges the encoded ultrasonic guided wave signal at the receiving node, and finally obtains the envelope of the decoded signal and calculates the corresponding peak value of the envelope. time, so as to obtain the specific location of the track break, which is implemented according to the following steps:

Step 1, using the Kasami sequence to encode the excitation signal to generate a coded ultrasonic guided wave signal, and the transmitting node transmits the coded ultrasonic guided wave signal;

Step 2. Turn on timing to detect the echo signal of the encoded ultrasonic guided wave signal;

Step 3, the receiving node collects the echo signal, and decodes the collected echo signal to obtain the decoded ultrasonic guided wave echo signal;

Step 4, using Hilbert transform to extract the envelope of the decoded ultrasonic guided wave echo signal;

Step 5. Judging the envelope characteristics to obtain the track break information, that is, if the encoded ultrasonic guided wave signal is received within the set time, the track break position is calculated, and the track break position is used as the track break information; otherwise, it is considered that the track break occurs at Blind zone, take the track break occurred in the blind zone as track break information;

Step 6, sending the track-breaking information in step 5 to the cloud server through the communication module;

Step 7: Distributing the track break detection information from the cloud server to each terminal through the Internet for processing, and the track break location detection is completed.

The second technical solution of the present invention is also characterized in that:

Both the piezoelectric transducer a and the piezoelectric transducer b are provided with two resonant frequencies f ₁ and f ₂ , and both satisfy f ₁ >f ₂ , wherein the resonant frequency f ₁ is used for rail damage or fracture detection, The resonance frequency f ₂ is used for orbital vibration energy recovery.

The excitation signal adopts a square wave signal with a frequency of 35kHz and a period of 4;

The number of bits of the Kasami sequence is 63 bits. Based on the BPSK modulation technique, the expression of the coded excitation signal e[k] is:

p[n]表示周期数为N_c＝4的方波信号，n＝k-i，其中，k表示编码激励信号的长度，i表示对所使用的63位Kasami序列进行过采样后的信号长度；N_s表示一个周期方波信号的采样点数；L表示所使用的Kasami序列长度。In formula (10), c[m] represents the oversampled signal of the 63-bit Kasami sequence used,

p[n] represents a square wave signal with a period number of N _c =4, n=ki, where k represents the length of the encoded excitation signal, and i represents the signal length after oversampling the used 63-bit Kasami sequence; N _s represents the number of sampling points of a periodic square wave signal; L represents the length of the Kasami sequence used.

In step 3, the collected echo signals are decoded to obtain the decoded ultrasonic guided wave echo signals. Specifically, the collected echo signals are subjected to Binary Phase Shift Keying, BPSK modulation and demodulation, and the BPSK demodulated signal y _d is calculated. [k],

In formula (11), y[l] represents the collected echo signal, l=i+k; p[n] represents a square wave signal with a period number of N _c =4, n=i;

Calculate the decoded ultrasonic guided wave echo signal t[k],

In formula (12), c[m] represents the 63-bit Kasami sequence used, and m=i.

The calculation of the track break position is as follows:

Assuming that the distance between the transmitting node and the receiving node is L ₁ , when the rail breaks in a certain detection interval, the NBIOT wireless communication modules a, a, and The NBIOT wireless communication module b with the positioning function sends the encoded ultrasonic guided wave signal used for the positioning of the broken track. At the same time, it is assumed that the distance from the receiving node x is the position of the broken track, then the calculation of x is as follows:

In formulas (13) and (14), x is the distance between the receiving node and the track-breaking position, t ₁ is the time difference from the transmission to the reception of the ultrasonic guided wave echo signal by the NBIOT wireless communication module a with positioning function; t ₂ is the time difference of the NBIOT wireless communication module b with positioning function from transmitting to receiving the ultrasonic guided wave echo signal; v _t is the propagation speed of the ultrasonic guided wave in the rail;

If t ₁ <t ₂ , formula (13) is used to calculate the track-breaking position; if t ₁ >t ₂ , formula (14) is used to calculate the track-breaking position.

The beneficial effects of the present invention are:

The present invention is a self-powered ultrasonic guided wave rail breaking real-time detection system, which fully utilizes the characteristics of the ultrasonic guided wave rail breaking detection system, adopts dual-frequency piezoelectric transducers in the detection system to integrate the rail vibration energy collection function, and solves the problem of existing problems. There is the problem of unstable power supply in the ultrasonic guided wave real-time rail break detection system. The three forms of energy in the railway monitoring site are fully utilized: solar energy, wind energy and track vibration, so as to ensure the reliability of the power supply of the railway site monitoring equipment and further improve the rail breakage. Accuracy of location detection.

The present invention is a method for positioning and detecting a broken track. At the same time, the Kasami sequence is used to encode the excitation signal, the ultrasonic guided wave echo signal is decoded and then the envelope is extracted, so that the propagation time of the ultrasonic guided wave signal can be measured more accurately, and the track break is greatly improved. Therefore, the reliability and detection accuracy of the ultrasonic guided wave track break detection system are improved, and the train operation safety is effectively guaranteed.

Description of drawings

FIG. 1 is a structural block diagram of a self-powered ultrasonic guided wave real-time detection system for rail broken according to the present invention.

Fig. 2 is a flow chart of positioning of a self-powered ultrasonic guided wave real-time detection system for rail broken according to the present invention.

In the figure, 1. Ultrasonic guided wave sending module, 2. Ultrasonic guided wave receiving module, 3. Communication module, 4. Terminal, 5. Self-powered module, 6. Piezoelectric transducer a, 7. NBIOT wireless communication module a , 8. Piezoelectric transducer b, 9. NBIOT wireless communication module b.

Detailed ways

The present invention will be described in detail below with reference to specific embodiments.

A self-powered ultrasonic guided wave rail-breaking real-time detection system of the present invention, as shown in Figure 1, includes:

The ultrasonic guided wave sending module 1 is a transmitting node with vibration energy collection function, which is used for transmitting ultrasonic guided wave signals. The ultrasonic guided wave sending module 1 includes a coding excitation circuit and a communication interface circuit a connected together, and the communication interface circuit a is respectively The piezoelectric transducer a6 with vibration energy collection function and the NBIOT wireless communication module a7 with positioning function are connected, the piezoelectric transducer a6 is fixed on the track to be detected, and the piezoelectric transducer a6 is provided with two resonance frequencies f ₁ and f ₂ , and both satisfy f ₁ >f ₂ , wherein the resonance frequency f ₁ is used for rail damage or fracture detection, and the resonance frequency f ₂ is used for rail vibration energy recovery;

The ultrasonic guided wave receiving module 2 is a receiving node with vibration energy collection function, which is used to receive ultrasonic guided wave signals. The ultrasonic guided wave receiving module includes a signal processing circuit and a communication interface circuit b that are connected together, and the communication interface circuit b is connected respectively. There are piezoelectric transducer b8 with vibration energy collection function, NBIOT wireless communication module b9 with positioning function, piezoelectric transducer b8 is fixed on the track to be detected, piezoelectric transducer b8 is provided with two resonance frequencies f ₁ and f ₂ , and both satisfy f ₁ >f ₂ , wherein the resonance frequency f ₁ is used for rail damage or fracture detection, and the resonance frequency f ₂ is used for rail vibration energy recovery;

The communication module 3 is used to send the track break information to the cloud server. The track break information is judged and processed by the ultrasonic guided wave receiving module 2. The communication module 3 includes a communication interface circuit c and an NBIOT communication module that are connected together. The communication interface circuit c Connect with the communication interface circuit a or the communication interface circuit b;

Terminal 4, connected to the cloud server, for receiving track break information;

The self-powered module 5 is used to provide electrical energy for the ultrasonic guided wave sending module 1, the ultrasonic guided wave receiving module 2 and the communication module 3. The self-powered module 5 includes a wind-solar hybrid power generation module, an orbital vibration power generation module, a wind-solar hybrid power generation module, and a rail vibration power generation module. The power generation modules are all connected with the AC-DC power conversion module, and the AC-DC power conversion module is respectively connected with the communication interface circuit a and the communication interface circuit b.

The ultrasonic guided wave sending module 1 and the ultrasonic guided wave receiving module 2 are alternately arranged with 1 km as a detection interval.

The present invention is a method for positioning and detecting a broken track. The self-powered ultrasonic guided wave track breakage real-time detection system of the present invention is used for positioning detection. Based on the mechanism of the same end transmitting and the same end receiving, the Kasami sequence is first used to detect the transmitted ultrasonic guided wave signal. Encoding is performed, and then the encoded ultrasonic guided wave signal is decoded and judged at the receiving node. Finally, the envelope of the decoded signal is obtained and the time corresponding to the envelope peak value is calculated to obtain the specific position of the track break, as shown in Figure 2. , according to the following steps:

Step 1, using the Kasami sequence to encode the excitation signal to generate a coded ultrasonic guided wave signal, and the transmitting node transmits the coded ultrasonic guided wave signal;

The excitation signal adopts a square wave signal with a frequency of 35kHz and a period of 4;

The number of bits of the Kasami sequence is 63 bits. Based on the BPSK modulation technique, the expression of the coded excitation signal e[k] is:

p[n]表示周期数为N_c＝4的方波信号，n＝k-i，其中，k表示编码激励信号的长度，i表示对所使用的63位Kasami序列进行过采样后的信号长度；N_s表示一个周期方波信号的采样点数；L表示所使用的Kasami序列长度。In formula (10), c[m] represents the oversampled signal of the 63-bit Kasami sequence used,

p[n] represents a square wave signal with a period number of N _c =4, n=ki, where k represents the length of the encoded excitation signal, and i represents the signal length after oversampling the used 63-bit Kasami sequence; N _s represents the number of sampling points of a periodic square wave signal; L represents the length of the Kasami sequence used.

Step 2: Start timing to detect the echo signal of the encoded ultrasonic guided wave signal.

Step 3, the receiving node collects the echo signal, and decodes the collected echo signal to obtain the decoded ultrasonic guided wave echo signal;

The decoding process is specifically as follows: Binary Phase Shift Keying is performed on the collected echo signal, BPSK modulation and demodulation is performed, and the BPSK demodulated signal y _d [k] is calculated,

In formula (11), y[l] represents the collected echo signal, l=i+k; p[n] represents a square wave signal with a period number of N _c =4, n=i;

Calculate the decoded ultrasonic guided wave echo signal t[k],

In formula (12), c[m] represents the 63-bit Kasami sequence used, and m=i.

Step 4, using Hilbert transform to extract the envelope of the decoded ultrasonic guided wave echo signal.

Step 5. Judging the envelope characteristics to obtain the track break information, that is, if the encoded ultrasonic guided wave signal is received within the set time, the track break position is calculated, and the track break position is used as the track break information; otherwise, it is considered that the track break occurs at Blind zone, take the track break occurred in the blind zone as track break information;

The calculation of the track break position is as follows:

Assuming that the distance between the transmitting node and the receiving node is L ₁ , when the rail breaks in a certain detection interval, the NBIOT wireless communication modules a7 and The NBIOT wireless communication module b9 with the positioning function sends the encoded ultrasonic guided wave signal used for the positioning of the broken track. At the same time, it is assumed that the distance from the receiving node x is the position of the broken track, then the calculation of x is as follows:

In formulas (13) and (14), x is the distance between the receiving node and the track-breaking position, t ₁ is the time difference from the transmission to the reception of the ultrasonic guided wave echo signal by the NBIOT wireless communication module a7 with positioning function; t ₂ is the time difference of the NBIOT wireless communication module b9 with positioning function from transmitting to receiving the ultrasonic guided wave echo signal; v _t is the propagation speed of the ultrasonic guided wave in the rail;

If t ₁ <t ₂ , formula (13) is used to calculate the track-breaking position; if t ₁ >t ₂ , formula (14) is used to calculate the track-breaking position.

Step 6. Send the track break information in Step 5 to the cloud server through the communication module 3.

Step 7: Distributing the track break detection information from the cloud server to each terminal 4 through the Internet for processing, and the track break location detection is completed.

Claims (10)

1. a self-powered ultrasonic guided wave rail-breaking real-time detection system, is characterized in that, comprising: The ultrasonic guided wave sending module (1) is a transmitting node with vibration energy collection function, and is used for transmitting ultrasonic guided wave signals; The ultrasonic guided wave receiving module (2) is a receiving node with a vibration energy collection function, and is used for receiving ultrasonic guided wave signals; a communication module (3) for sending track break information to the cloud server, where the track break information is determined and processed by the ultrasonic guided wave receiving module (2); A terminal (4), connected to the cloud server, for receiving track-breaking information; The self-powered module (5) is used for providing electric power for the ultrasonic guided wave sending module (1), the ultrasonic guided wave receiving module (2) and the communication module (3). 2. A kind of self-powered ultrasonic guided wave broken rail real-time detection system according to claim 1, is characterized in that, described ultrasonic guided wave sending module (1) and ultrasonic guided wave receiving module (2) take 1km as a The detection intervals are alternately arranged, and the ultrasonic guided wave sending module (1) or the ultrasonic guided wave receiving module (2) located at one end of the alternate arrangement is connected with the communication module (3). 3. a kind of self-powered ultrasonic guided wave broken rail real-time detection system according to claim 1, is characterized in that, described ultrasonic guided wave sending module (1) comprises the coding excitation circuit and the communication interface circuit a that are connected together , the communication interface circuit a is respectively connected with a piezoelectric transducer a (6) with a vibration energy collection function and an NBIOT wireless communication module a (7) with a positioning function, and the piezoelectric transducer a (6) is fixed on the track to be detected; The ultrasonic guided wave receiving module includes a signal processing circuit and a communication interface circuit b that are connected together, and the communication interface circuit b is respectively connected with a piezoelectric transducer b (8) with a vibration energy collection function, an NBIOT wireless with a positioning function. Communication module b(9), the piezoelectric transducer b(8) is fixed on the track to be detected. 4. a kind of self-powered ultrasonic guided wave rail-breaking real-time detection system according to claim 3, is characterized in that, described communication module (3) comprises the communication interface circuit c and NBIOT communication module that are connected together, described The communication interface circuit c is connected to the communication interface circuit a or the communication interface circuit b. 5. A kind of self-powered ultrasonic guided wave rail-breaking real-time detection system according to claim 3, wherein the self-powered energy module (5) comprises a wind-solar hybrid power generation module and an orbital vibration power generation module, and the wind-solar hybrid power generation module The power generation module and the rail vibration power generation module are all connected with an AC-DC power conversion module, and the AC-DC power conversion module is respectively connected with the communication interface circuit a and the communication interface circuit b. 6. A method for positioning and detecting a broken rail, using the self-powered ultrasonic guided wave broken rail real-time detection system as claimed in any one of claims 1-5 to carry out positioning detection, it is characterized in that, based on the same-end transmitting and receiving at the same end. Mechanism, first use the Kasami sequence to encode the transmitted ultrasonic guided wave signal, then decode and judge the encoded ultrasonic guided wave signal at the receiving node, and finally obtain the envelope of the decoded signal and calculate the time corresponding to the envelope peak value, Thereby, the specific position of the broken rail can be obtained, and the specific steps are as follows: Step 1, using the Kasami sequence to encode the excitation signal to generate a coded ultrasonic guided wave signal, and the transmitting node transmits the coded ultrasonic guided wave signal; Step 2. Turn on timing to detect the echo signal of the encoded ultrasonic guided wave signal; Step 3, the receiving node collects the echo signal, and decodes the collected echo signal to obtain the decoded ultrasonic guided wave echo signal; Step 4, using Hilbert transform to extract the envelope of the decoded ultrasonic guided wave echo signal; Step 5. Judging the envelope characteristics to obtain the track break information, that is, if the encoded ultrasonic guided wave signal is received within the set time, the track break position is calculated, and the track break position is used as the track break information; otherwise, it is considered that the track break occurs at Blind zone, take the track break occurred in the blind zone as track break information; Step 6, sending the track-breaking information in step 5 to the cloud server through the communication module (3); Step 7: Distributing the track break detection information from the cloud server to each terminal (4) through the Internet for processing, and the track break location detection is completed. 7. A kind of rail broken positioning detection method according to claim 6, is characterized in that, piezoelectric transducer a (6) and piezoelectric transducer b (8) are provided with two resonance frequencies f ₁ and f ₂ , and both satisfy f ₁ >f ₂ , wherein the resonance frequency f ₁ is used for rail damage or fracture detection, and the resonance frequency f ₂ is used for rail vibration energy recovery. 8. A kind of rail-broken positioning detection method according to claim 6, is characterized in that, described excitation signal adopts the square wave signal whose frequency is 35kHz, and the number of cycles is 4; The number of bits of the Kasami sequence is 63 bits. Based on the BPSK modulation technology, the expression of the coded excitation signal e[k] is:

In formula (10), c[m] represents the oversampled signal of the 63-bit Kasami sequence used,

p[n] represents a square wave signal with a period number of N _c =4, n=ki, where k represents the length of the encoded excitation signal, and i represents the signal length after oversampling the used 63-bit Kasami sequence; N _s represents the number of sampling points of a periodic square wave signal; L represents the length of the Kasami sequence used. 9 . A method for detecting track breakage according to claim 8 , wherein in the step 3, the collected echo signals are decoded, and the decoded ultrasonic guided wave echo signals obtained are specifically: 9 . The echo signal is subjected to BinaryPhase Shift Keying, BPSK modulation and demodulation, and the BPSK demodulated signal y _d [k] is calculated,

In formula (11), y[l] represents the collected echo signal, l=i+k; p[n] represents a square wave signal with a period number of N _c =4, n=i; Calculate the decoded ultrasonic guided wave echo signal t[k],

In formula (12), c[m] represents the 63-bit Kasami sequence used, and m=i. 10. A rail-broken positioning detection method according to claim 6, wherein the calculating the rail-broken position is specifically: Assuming that the distance between the transmitting node and the receiving node is L ₁ , when the rail breaks in a certain detection interval, the NBIOT wireless communication module a ( 7), the NBIOT wireless communication module b(9) with the positioning function sends the encoded ultrasonic guided wave signal used for the positioning of the broken track, and at the same time, it is assumed that the distance from the receiving node x is the position of the broken track, then x is calculated as follows:

In equations (13) and (14), x is the distance between the receiving node and the track-breaking position, and t ₁ is the distance between the NBIOT wireless communication module a (7) with the positioning function from transmitting to receiving the ultrasonic guided wave echo signal. Time difference; t ₂ is the time difference between the NBIOT wireless communication module b(9) with the positioning function from transmitting to receiving the ultrasonic guided wave echo signal; v _t is the propagation speed of the ultrasonic guided wave in the rail; If t ₁ <t ₂ , formula (13) is used to calculate the track-breaking position; if t ₁ >t ₂ , formula (14) is used to calculate the track-breaking position.

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