Ad hoc network acoustic emission acquisition device and system

Abstract

The invention discloses an Ad hoc network acoustic emission acquisition device and system.The acquisition device comprises a preprocessing module, a fault processing module, a feature frame management module, a signal feature processing module and an evaluation and judgment module, the fault processing module is used for processing faults of network connection, the feature frame management module is used for managing feature frames, the signal feature processing module is used for analyzing and calculating a distance reference value, and the evaluation and judgment module is used for judging whether clocks of the acquisition devices are synchronous or not, the fault processing module comprises a network detection unit, a cache management unit and a networking time period management unit, the signal feature processing module comprises a signal decomposition unit, a feature frame analysis unit and a distance analysis unit, and the evaluation and judgment module comprises a distance evaluation coefficient calculation unit, a reference distance calculation unit and a time evaluation unit.

Description

Technical Field

[0001] The invention relates to the technical field of network equipment management, in particular to a self-organizing network acoustic emission collection device and system. Background Art

[0002] Ad hoc network technology allows a group of devices to communicate with each other without fixed infrastructure. This network is usually composed of mobile nodes, each of which can act as both a terminal device and a router. By forming a sound collection array with multiple sound collection devices, the sound information of the same sound source can be collected from different angles or distances, so that more sound source information can be recorded.

[0003] In the sound collection array, each sound collection device terminal needs to be time synchronized in order to align the audio track of the sound source. In the actual application of the sound collection array, due to network fluctuations, individual collection device terminals will be disconnected, and the remaining collection device terminals will re-organize the network according to the routing information. After self-organizing the network, in order to ensure the uniformity of the time dimension of the collected sound source, the clock of the sound collection device terminal in the network needs to be resynchronized. In the prior art, it is usually necessary to find a time server in the network system for re-timing, which requires a long communication link and a more complex network time protocol. The sound collection array is often built independently, and the cost of deploying a time server separately is high. In addition, when collecting sound at high speed, the waiting time for network timing needs to be shortened as much as possible, so the traditional time synchronization solution is difficult to apply. Summary of the invention

[0004] The purpose of the present invention is to provide a self-organizing network acoustic emission collection device and system to solve the problems raised in the prior art.

[0005] To achieve the above-mentioned purpose, the present invention provides the following technical solutions: a self-organizing network acoustic emission collection device, the collection device includes: a preprocessing module, a fault processing module, a feature frame management module, a signal feature processing module and an evaluation and judgment module, wherein the preprocessing module is used to preprocess the historical transmission information of the collection device, the fault processing module is used to process the network connection fault, the feature frame management module is used to manage the feature frame inserted after the cache data, the signal feature processing module is used to analyze the feature frame and the received signal to calculate the distance reference value, and the evaluation and judgment module calculates the reference record and judges whether the clock of the collection device is synchronized.

[0006] Furthermore, the preprocessing module includes: a historical data management unit, a feature management unit and a distance function management unit, wherein the historical data management unit is used to collect historical transmission records of the device, the feature management unit is used to obtain signal characteristics of the transmission signal, and the distance function management unit is used to manage the first distance function and the second distance function.

[0007] Furthermore, the fault handling module includes: a network detection unit, a cache management unit and a networking period management unit, wherein the network detection unit is used to detect the network connection quality between the collection devices, the cache management unit is used to cache the data collected by the collection devices, and the networking period management unit is used to manage the networking period between the collection devices.

[0008] Furthermore, the signal feature processing module includes: a signal decomposition unit, a feature frame parsing unit and a distance analysis unit, wherein the signal decomposition unit is used to decompose the received signal, the feature frame parsing unit is used to obtain information from the feature frame, and the distance analysis unit is used to calculate the first distance reference value and the second distance reference value respectively through the first distance function and the second distance function.

[0009] Furthermore, the evaluation and judgment module includes: a distance evaluation coefficient calculation unit, a reference distance calculation unit and a time evaluation unit, wherein the distance evaluation coefficient calculation unit is used to calculate the distance evaluation coefficient through a coefficient calculation function, the reference distance calculation unit is used to calculate the reference distance, and the time evaluation unit is used to evaluate whether the clock of the acquisition device is synchronized.

[0010] A self-organizing network acoustic emission collection system is used to perform a self-organizing network acoustic emission collection method, the method comprising:

[0011] Obtain historical data of transmission signals of any two identical acquisition terminals, and obtain a first distance function of the attenuation of the effective part of the signal with distance and a second distance function of the increase of the interference part of the signal with distance according to the signal characteristics of the transmitting end signal and the receiving end signal;

[0012] Three identical collection terminals are connected through a self-organizing network protocol. When a network connection failure occurs between a first collection terminal and a second collection terminal, the first collection terminal caches the collected data, and a time period during which the first collection terminal is disconnected from the second collection terminal and the first collection terminal is connected to the third collection terminal is recorded as a networking time period.

[0013] At the end of the networking period, the first acquisition terminal inserts a feature frame containing clock information and signal characteristics of the transmitted signal, and sends the cached data, the feature frame, and the data collected after the networking period to the third acquisition terminal, which caches the received data and records the time from the start of receiving the data to the receipt of the feature frame;

[0014] The third acquisition terminal obtains the signal characteristics of the received signal, extracts the signal characteristics of the transmitted signal from the characteristic frame, obtains the first distance function and the second distance function, and calculates the first distance reference value and the second distance reference value through the characteristic values ​​of the signal characteristics;

[0015] The average value of the signal-to-noise ratio of the received signal is obtained, and the weights of the first distance reference value and the second distance reference value are calculated through a coefficient calculation function. The first distance reference value and the second distance are weighted to obtain a reference distance L. The signal transmission speed is obtained to calculate the transmission time. The time difference between the clock of the first acquisition terminal and the clock of the third acquisition terminal is calculated by combining the time from the start of receiving data to the receipt of the characteristic frame. The time difference is compared with the difference threshold to determine whether the clocks of the first acquisition terminal and the third acquisition terminal are synchronized.

[0016] Further, historical data of signal transmission between two acquisition terminals is obtained, and a signal transmitted in any piece of historical data is used as a target signal;

[0017] The distance from the sending end that sends the target signal to the receiving end that receives the target signal is recorded as the transmission distance, and the signal feature of the target signal at the sending end is recorded as the first target feature;

[0018] Acquire a signal of a target signal at a receiving end, decompose the signal into a first part and a second part, record a signal feature of the first part of the signal at the receiving end as a second target feature, and record a signal feature of the second part of the signal at the receiving end as a third target feature;

[0019] Obtain the characteristic value r1 of the first target feature and the characteristic value m21 of the second target feature, calculate the difference v1, v1=r1-m21, record the difference as the target difference, and form the target difference and the transmission distance d into a first data group (v1, d), obtain the characteristic value m22 of the third target feature, and form the characteristic value of the third target feature and the transmission distance into a second data group (m22, d);

[0020] By adjusting the transmission distance, a plurality of historical data of the signal transmission of the acquisition terminal are obtained, and the first data group and the second data group of all the historical data are respectively collected;

[0021] When the first target feature is a certain characteristic value, the functional relationship between the target difference and the transmission distance is obtained, and the functional relationship is recorded as the first distance function F1(D); the functional relationship between the characteristic value of the third target feature and the transmission distance is obtained, and the functional relationship is recorded as the second distance function F2(D), where F1 and F2 are the functional relationships of the first distance function and the second distance function respectively, and D represents the distance variable;

[0022] A corresponding relationship between the feature value of the first target feature and the first distance function and the second distance function is established.

[0023] Further, three identical collection terminals are connected via a network line type, the three collection terminals are a first collection terminal, a second collection terminal and a third collection terminal in order of connection, and the collection terminals are deployed with a self-organizing network protocol;

[0024] When the first acquisition terminal detects that the network connection with the second acquisition terminal fails, the collected data is cached in the first cache unit of the first acquisition terminal;

[0025] The time period when the first acquisition terminal is disconnected from the second acquisition terminal and the time period when the third acquisition terminal is disconnected from the second acquisition terminal is recorded as the networking period.

[0026] Furthermore, the first acquisition terminal inserts a feature frame at the end of the networking period, the feature frame including the clock information of the first acquisition terminal and the signal characteristics of the transmitted signal, and the first acquisition terminal sends the data cached in the first cache unit, the feature frame and the data collected after the networking period to the third acquisition terminal;

[0027] After receiving the data sent by the first collection terminal, the third collection terminal stores the data in the second cache unit of the third collection terminal, and records the time from the start of receiving the data sent by the first collection terminal to receiving the feature frame as the cache period.

[0028] Further, the data transmission signal sent by the first acquisition terminal and received by the third acquisition terminal during the buffer period is recorded as a received signal, the received signal is decomposed into a first part and a second part, and a signal feature of the first part of the received signal and a signal feature of the second part of the received signal are obtained respectively;

[0029] The first part of the signal is the useful signal to be transmitted, and the second part is the noise signal of the signal. The transmission distance is estimated by calculating the attenuation of the signal with the distance during the transmission process and the increase of the noise signal with the distance;

[0030] The third acquisition terminal obtains the signal feature of the transmission signal of the signal from the feature frame, obtains the signal feature of the transmission end signal that is the same as the signal feature of the transmission signal, and obtains the first distance function F11(D) and the second distance function F21(D) corresponding to the feature value of the signal feature;

[0031] Obtain the characteristic value y1 of the signal characteristic of the transmitted signal and the characteristic value n21 of the signal characteristic of the first part of the received signal, calculate w1, w1=y1-n21, solve the equation w1=F11(D) to obtain the first distance reference value h1, obtain the characteristic value n22 of the signal characteristic of the second part of the received signal, solve the equation n22=F21(D) to obtain the second distance reference value h2.

[0032] Furthermore, the average value of the signal-to-noise ratio of the received signal is obtained and recorded as SNR, and the function G is calculated by the coefficient, The calculation result of the function is recorded as the distance evaluation coefficient α, where k and c represent different parameters respectively;

[0033] Usually, the recommended value of SNR in data transmission network is above 20dB, that is, the power of effective signal is more than 100 times of the power of noise signal. Therefore, the transmission distance prediction value calculated based on effective signal and noise signal is not uniform in accuracy. The larger the signal-to-noise ratio, the larger the proportion of the first part of the signal.

[0034] Therefore, by collecting the signal-to-noise ratio, the distance data calculated by the two methods are balanced using the coefficient calculation function, so that the calculated reference distance is more accurate;

[0035] Calculate the reference distance L, L = α × h1 + β × h2, where β = 1-α;

[0036] Set the signal transmission speed value cv and calculate the transmission time t tran , t tran =L / cv;

[0037] A difference threshold p is set, and T3-T1=δ is calculated. When |δ|>p, the clock of the first acquisition terminal is not synchronized with the clock of the third acquisition terminal.

[0038] Compared with the prior art, the present invention has the following beneficial effects:

[0039] 1. Perform time calibration with the network terminal that is disconnected and reconnected through the terminal with stable network status, and reduce the dependence on time server timing in the data acquisition network with relatively simple network equipment. At the same time, simplify the timing process, so that the adjacent data acquisition terminals can realize the synchronization function of network rapid recovery.

[0040] 2. Reduce data loss caused by network disconnection and time asynchrony during the timing process, and improve the data integrity of data collection results. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 It is a structural schematic diagram of the self-organizing network acoustic emission collection device of the present invention;

[0042] Figure 2 A schematic diagram of an embodiment of a self-organizing network acoustic emission collection device and system of the present invention;

[0043] Figure 3 It is a schematic diagram of an embodiment of a self-organizing network acoustic emission collection device and system of the present invention. DETAILED DESCRIPTION

[0044] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0045] Example: Figure 1 , Figure 2 and Figure 3 As shown, the present invention provides a technical solution, a self-organizing network acoustic emission collection device;

[0046] The acquisition device includes: a pre-processing module, a fault processing module, a feature frame management module, a signal feature processing module and an evaluation and judgment module;

[0047] The preprocessing module is used to preprocess the historical transmission information of the collection device, wherein the preprocessing module includes: a historical data management unit, a feature management unit and a distance function management unit, wherein the historical data management unit is used to collect the historical transmission records of the collection device, the feature management unit is used to obtain the signal characteristics of the transmission signal, and the distance function management unit is used to manage the first distance function and the second distance function;

[0048] The fault handling module is used to handle the network connection fault, wherein the fault handling module includes: a network detection unit, a cache management unit and a networking period management unit, wherein the network detection unit is used to detect the network connection quality between the collection devices, the cache management unit is used to cache the data collected by the collection device, and the networking period management unit is used to manage the networking period between the collection devices;

[0049] Wherein, the feature frame management module is used to manage the feature frames inserted after the cached data;

[0050] The signal feature processing module is used to analyze the feature frame and the received signal to calculate the distance reference value, wherein the signal feature processing module includes: a signal decomposition unit, a feature frame parsing unit and a distance analysis unit, wherein the signal decomposition unit is used to decompose the received signal, the feature frame parsing unit is used to obtain information from the feature frame, and the distance analysis unit is used to calculate the first distance reference value and the second distance reference value respectively through the first distance function and the second distance function;

[0051] Among them, the evaluation and judgment module calculates the reference record and judges whether the clock of the acquisition device is synchronized. Among them, the evaluation and judgment module includes: a distance evaluation coefficient calculation unit, a reference distance calculation unit and a time evaluation unit. Among them, the distance evaluation coefficient calculation unit is used to calculate the distance evaluation coefficient through the coefficient calculation function, the reference distance calculation unit is used to calculate the reference distance, and the time evaluation unit is used to evaluate whether the clock of the acquisition device is synchronized.

[0052] A self-organizing network acoustic emission collection system is used to perform a self-organizing network acoustic emission collection method, the method comprising:

[0053] Obtain historical data of transmission signals of any two identical acquisition terminals, and obtain a first distance function of the attenuation of the effective part of the signal with distance and a second distance function of the increase of the interference part of the signal with distance according to the signal characteristics of the transmitting end signal and the receiving end signal;

[0054] Among them, historical data of signal transmission between two acquisition terminals is obtained, and a signal transmitted in any piece of historical data is used as a target signal;

[0055] The distance from the sending end that sends the target signal to the receiving end that receives the target signal is recorded as the transmission distance, and the signal feature of the target signal at the sending end is recorded as the first target feature;

[0056] Acquire a signal of a target signal at a receiving end, decompose the signal into a first part and a second part, record a signal feature of the first part of the signal at the receiving end as a second target feature, and record a signal feature of the second part of the signal at the receiving end as a third target feature;

[0057] Obtain the characteristic value r1 of the first target feature and the characteristic value m21 of the second target feature, calculate the difference v1, v1=r1-m21, record the difference as the target difference, and form the target difference and the transmission distance d into a first data group (v1, d), obtain the characteristic value m22 of the third target feature, and form the characteristic value of the third target feature and the transmission distance into a second data group (m22, d);

[0058] By adjusting the transmission distance, a plurality of historical data of the signal transmission of the acquisition terminal are obtained, and the first data group and the second data group of all the historical data are respectively collected;

[0059] When the first target feature is a certain characteristic value, the functional relationship between the target difference and the transmission distance is obtained, and the functional relationship is recorded as the first distance function F1(D); the functional relationship between the characteristic value of the third target feature and the transmission distance is obtained, and the functional relationship is recorded as the second distance function F2(D), where F1 and F2 are the functional relationships of the first distance function and the second distance function respectively, and D represents the distance variable;

[0060] A corresponding relationship between the feature value of the first target feature and the first distance function and the second distance function is established.

[0061] Three identical collection terminals are connected through a self-organizing network protocol. When a network connection failure occurs between a first collection terminal and a second collection terminal, the first collection terminal caches the collected data, and a time period during which the first collection terminal is disconnected from the second collection terminal and the first collection terminal is connected to the third collection terminal is recorded as a networking time period.

[0062] Wherein, three identical collection terminals are connected via a network line type, and the three collection terminals are sequentially a first collection terminal, a second collection terminal, and a third collection terminal according to the connection order, and the collection terminals are deployed with a self-organizing network protocol;

[0063] When the first acquisition terminal detects that the network connection with the second acquisition terminal fails, the collected data is cached in the first cache unit of the first acquisition terminal;

[0064] The time period when the first acquisition terminal is disconnected from the second acquisition terminal and the time period when the third acquisition terminal is disconnected from the second acquisition terminal is recorded as the networking period.

[0065] At the end of the networking period, the first acquisition terminal inserts a feature frame containing clock information and signal characteristics of the transmitted signal, and sends the cached data, the feature frame, and the data collected after the networking period to the third acquisition terminal, which caches the received data and records the time from the start of receiving the data to the receipt of the feature frame;

[0066] In an embodiment, the signal characteristics of the target signal include: transmission power, transmission frequency, center frequency, waveform image characteristics of the time domain signal and waveform image characteristics of the frequency domain signal;

[0067] The first acquisition terminal inserts a characteristic frame at the end of the networking period, the characteristic frame including the clock information of the first acquisition terminal and the signal characteristics of the transmitted signal, and the first acquisition terminal sends the data cached in the first cache unit, the characteristic frame and the data collected after the networking period to the third acquisition terminal;

[0068] After receiving the data sent by the first collection terminal, the third collection terminal stores the data in the second cache unit of the third collection terminal, and records the time from the start of receiving the data sent by the first collection terminal to receiving the feature frame as the cache period.

[0069] The third acquisition terminal obtains the signal characteristics of the received signal, extracts the signal characteristics of the transmitted signal from the characteristic frame, obtains the first distance function and the second distance function, and calculates the first distance reference value and the second distance reference value through the characteristic values ​​of the signal characteristics;

[0070] The data transmission signal sent by the first acquisition terminal and received by the third acquisition terminal during the buffer period is recorded as a received signal, the received signal is decomposed into a first part and a second part, and a signal feature of the first part of the received signal and a signal feature of the second part of the received signal are obtained respectively;

[0071] The third acquisition terminal obtains the signal feature of the transmission signal of the signal from the feature frame, obtains the signal feature of the transmission end signal that is the same as the signal feature of the transmission signal, and obtains the first distance function F11(D) and the second distance function F21(D) corresponding to the feature value of the signal feature;

[0072] Obtain the characteristic value y1 of the signal characteristic of the transmitted signal and the characteristic value n21 of the signal characteristic of the first part of the received signal, calculate w1, w1=y1-n21, solve the equation w1=F11(D) to obtain the first distance reference value h1, obtain the characteristic value n22 of the signal characteristic of the second part of the received signal, solve the equation n22=F21(D) to obtain the second distance reference value h2.

[0073] Obtain the average value of the received signal-to-noise ratio, calculate the weights of the first distance reference value and the second distance reference value through a coefficient calculation function, perform weighted operation on the first distance reference value and the second distance to obtain a reference distance L, obtain the signal transmission speed to calculate the transmission time, combine the time from the start of receiving data to the reception of the characteristic frame, calculate the time difference between the clock of the first acquisition terminal and the clock of the third acquisition terminal, compare the time difference with the difference threshold, and determine whether the clocks of the first acquisition terminal and the third acquisition terminal are synchronized;

[0074] The average value of the signal-to-noise ratio of the received signal is recorded as SNR, and the function G is calculated by the coefficient. The calculation result of the function is recorded as the distance evaluation coefficient α, where k and c represent different parameters respectively;

[0075] In the embodiment, k is 0.2197, and c is 20;

[0076] When SNR = 20 (dB), α is about 0.5, and when SNR = 30 (dB), α is about 0.9. In the actual calculation process, SNR is converted into dB and the value is substituted into the formula for calculation;

[0077] Calculate the reference distance L, L = α × h1 + β × h2, where β = 1-α;

[0078] Set the signal transmission speed value cv and calculate the transmission time t tran , t tran =L / cv;

[0079] A difference threshold p is set, and T3-T1=δ is calculated. When |δ|>p, the clock of the first acquisition terminal is not synchronized with the clock of the third acquisition terminal.

[0080] In one embodiment, the ad hoc network acoustic emission collection terminal includes: a network connection unit, a connection detection unit, a clock management unit, a routing management unit, a time information management unit, a feedback unit, a cache module, a signal analysis module, a distance calculation module and a delay detection module;

[0081] The network connection unit is used to manage the network connection of the acquisition device, wherein the network connection unit includes a signal sending end and a signal receiving end, the signal sending end is used to send signals, and the signal receiving end is used to receive signals;

[0082] The connection detection unit is used to detect whether there is an abnormality in data transmission;

[0083] The clock management unit is used to manage the local clock information of the acquisition device;

[0084] The routing management unit is used for self-organizing networks and managing routing information;

[0085] The time information management unit is used to insert a feature frame between the cached data and the currently transmitted data, wherein the feature frame includes clock information and signal characteristics of the transmitted signal;

[0086] The feedback unit is used to send clock correction information to the signal sending section when the difference between the clock information of the received signal and the local clock information is greater than the difference threshold;

[0087] The cache module is used to save data;

[0088] The cache module includes a first cache unit and a second cache unit. The first cache unit is used to cache data. When the sending end of the acquisition device sends an abnormal signal, the collected data is cached in the first cache unit. The second cache unit is used to cache data. When the acquisition device completes the network connection, the received data is cached in the second cache unit.

[0089] The signal analysis module is used to analyze the received signal and obtain the signal characteristics of the received signal;

[0090] The signal analysis module includes: a signal decomposition unit and a feature extraction unit, wherein the signal decomposition unit is used to obtain a signal and decompose the signal into a first part and a second part, wherein the first part is a valid part of the signal and the second part is a remaining part of the signal after removing the first part, and the feature extraction unit is used to obtain signal features of the first part and the second part of the signal respectively;

[0091] The distance calculation module is used to calculate the reference distance between the sending end and the receiving end through the signal received by the receiving end;

[0092] The distance calculation module includes a first transmission management unit, a second transmission management unit, a signal-to-noise ratio management unit, an evaluation coefficient calculation unit and a reference distance calculation unit, wherein the first transmission management unit is used to calculate the transmission distance of the signal according to the attenuation characteristics of the effective part of the signal, and the transmission distance calculated by the first transmission management unit is recorded as the first distance reference value, the second transmission management unit is used to calculate the transmission distance of the signal according to the characteristics added to the second part of the signal, and the transmission distance calculated by the second transmission management unit is recorded as the second distance reference value, the signal-to-noise ratio management unit is used to obtain the signal-to-noise ratio of the signal, the evaluation coefficient calculation unit is used to calculate the distance evaluation coefficient through the coefficient calculation function, and the reference distance calculation unit is used to calculate the reference distance;

[0093] The delay detection module is used to obtain the reference distance to calculate the transmission time of the received signal, and to obtain the clock information of the received signal and compare it with the local clock information of the acquisition device.

[0094] In the embodiment, three acquisition terminals are included, which are respectively recorded as acquisition terminal A1, acquisition terminal A2 and acquisition terminal A3. In the initial network, acquisition terminal A1, acquisition terminal A2 and acquisition terminal A3 are connected in sequence;

[0095] Q1. When the collection terminal A1 detects network fluctuations at the signal sending end, the locally collected data is cached in the first cache unit;

[0096] Q2, after the collection terminal A1 disconnects the network connection with the collection terminal A2 and establishes the network connection with the collection terminal A3, the collection terminal A1 inserts the feature frame between the buffered information and the current collection information, and sends it to the collection terminal A3 in the order of collection time;

[0097] Q3, the data received by the collection terminal A3 from the collection terminal A1 is stored in the second cache unit of the collection terminal A3, and when the characteristic frame is received, it stops obtaining the connection information with the other end, and obtains the time t when the collection terminal A3 stores the data in the second cache unit buffer ;

[0098] Q4, obtaining a signal from a signal receiving end of the acquisition terminal A3, decomposing the signal into a first part and a second part, and obtaining signal features of the first part and signal features corresponding to the second part;

[0099] Q5. Obtain the signal feature of the transmitted signal of the signal from the feature frame, obtain the first target feature that is the same as the signal feature of the transmitted signal, obtain the corresponding first change rule and second change rule, and respectively calculate the first distance reference value h1 corresponding to the first change rule and the second distance reference value h2 corresponding to the second change rule;

[0100] Q6, obtain the signal-to-noise ratio SNR of the signal at the signal receiving end of the acquisition terminal A3, and calculate the distance evaluation coefficient α through the coefficient calculation function;

[0101] Q7. Calculate the reference distance d, d = α × h1 + β × h2, where β = 1-α;

[0102] Q8. Obtain the signal transmission constant v and calculate the transmission time t tran , t tran =d / v;

[0103] Q9. When the acquisition terminal A3 receives the characteristic frame, it records the clock information T2 of the acquisition terminal A3, obtains the clock information T1 of the acquisition terminal A1 from the characteristic frame, and calculates the comparison time T3, T3 = T2-(t tran +t buffer );

[0104] Q10, obtain the difference threshold p, calculate T3-T1=δ, when |δ|>p, the clock of the acquisition terminal A1 is not synchronized with the clock of the acquisition terminal A3;

[0105] Q11. When δ>0, the clock of the collection terminal A1 is slower than that of the collection terminal A3. When δ<0, the clock of the collection terminal A1 is faster than that of the collection terminal A3. The collection terminal A3 sends clock correction information to the collection terminal A1.

[0106] It will be apparent to those skilled in the art that the invention is not limited to the details of the exemplary embodiments described above and that the invention can be implemented in other specific forms without departing from the spirit or essential features of the invention. Therefore, the embodiments should be considered exemplary and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations falling within the meaning and scope of the equivalent elements of the claims be included in the invention. Any reference numeral in a claim should not be considered as limiting the claim to which it relates.

Claims

1. The self-organizing network acoustic emission collection system is characterized by: The workflow of the system is as follows: Obtain historical data of transmission signals of any two identical acquisition terminals, and obtain a first distance function of the attenuation of the effective part of the signal with distance and a second distance function of the increase of the interference part of the signal with distance according to the signal characteristics of the transmitting end signal and the receiving end signal; Three identical collection terminals are connected through a self-organizing network protocol. When a network connection failure occurs between a first collection terminal and a second collection terminal, the first collection terminal caches the collected data, and a time period during which the first collection terminal is disconnected from the second collection terminal and the first collection terminal is connected to the third collection terminal is recorded as a networking time period. At the end of the networking period, the first acquisition terminal inserts a feature frame containing clock information and signal characteristics of the transmitted signal, and sends the cached data, the feature frame, and the data collected after the networking period to the third acquisition terminal, which caches the received data and records the time from the start of receiving the data to the receipt of the feature frame; The third acquisition terminal obtains the signal characteristics of the received signal, extracts the signal characteristics of the transmitted signal from the characteristic frame, obtains the first distance function and the second distance function, and calculates the first distance reference value and the second distance reference value through the characteristic values ​​of the signal characteristics; The average value of the signal-to-noise ratio of the received signal is obtained, and the weights of the first distance reference value and the second distance reference value are calculated through a coefficient calculation function. The first distance reference value and the second distance are weighted to obtain a reference distance L. The signal transmission speed is obtained to calculate the transmission time. The time difference between the clock of the first acquisition terminal and the clock of the third acquisition terminal is calculated by combining the time from the start of receiving data to the receipt of the characteristic frame. The time difference is compared with the difference threshold to determine whether the clocks of the first acquisition terminal and the third acquisition terminal are synchronized.

2. The ad hoc network acoustic emission collection system according to claim 1, characterized in that: The system executes the following workflow to obtain the first distance function and the second distance function based on the signal characteristics of the transmitting end signal and the receiving end signal: Obtain the historical data of signal transmission between two acquisition terminals, and use the signal transmitted in any piece of historical data as the target signal; The distance from the sending end that sends the target signal to the receiving end that receives the target signal is recorded as the transmission distance, and the signal feature of the target signal at the sending end is recorded as the first target feature; Acquire a signal of a target signal at a receiving end, decompose the signal into a first part and a second part, record a signal feature of the first part of the signal at the receiving end as a second target feature, and record a signal feature of the second part of the signal at the receiving end as a third target feature; Obtain the characteristic value r1 of the first target feature and the characteristic value m21 of the second target feature, calculate the difference v1, v1=r1-m21, record the difference as the target difference, combine the target difference and the transmission distance d into a first data group (v1, d), obtain the characteristic value m22 of the third target feature, and combine the characteristic value of the third target feature and the transmission distance into a second data group (m22, d); By adjusting the transmission distance, a plurality of historical data of the signal transmission of the acquisition terminal are obtained, and the first data group and the second data group of all the historical data are respectively collected; When the first target feature is a certain characteristic value, obtain the functional relationship between the target difference and the transmission distance, and record the functional relationship as the first distance function F1(D); obtain the functional relationship between the characteristic value of the third target feature and the transmission distance, and record the functional relationship as the second distance function F2(D), wherein F1 and F2 are the functional relationships of the first distance function and the second distance function respectively, and D represents the distance variable; A corresponding relationship between the feature value of the first target feature and the first distance function and the second distance function is established.

3. The ad hoc network acoustic emission collection system according to claim 2, characterized in that: The system executes the following workflow to obtain the networking time period: Connect three identical acquisition terminals through a network line type, wherein the three acquisition terminals are a first acquisition terminal, a second acquisition terminal and a third acquisition terminal in order of connection, and the acquisition terminals are deployed with a self-organizing network protocol; When the first acquisition terminal detects that the network connection with the second acquisition terminal fails, the collected data is cached in the first cache unit of the first acquisition terminal; The time period when the first acquisition terminal is disconnected from the second acquisition terminal and the time period when the third acquisition terminal is disconnected from the second acquisition terminal is recorded as the networking period.

4. The ad hoc network acoustic emission collection system according to claim 3, characterized in that: The system executes the management process of feature frames as follows: The first acquisition terminal inserts a feature frame at the end of the networking period, wherein the feature frame includes the clock information of the first acquisition terminal and the signal characteristics of the transmitted signal, and the first acquisition terminal sends the data cached in the first cache unit, the feature frame, and the data collected after the networking period to the third acquisition terminal; After receiving the data sent by the first collection terminal, the third collection terminal stores the data in the second cache unit of the third collection terminal, and records the time from the start of receiving the data sent by the first collection terminal to receiving the feature frame as the cache period.

5. The ad hoc network acoustic emission collection system according to claim 4, characterized in that: The system performs the calculation process of the first distance reference value and the second distance reference value as follows: Recording the data transmission signal sent by the first acquisition terminal and received by the third acquisition terminal during the buffer period as a received signal, decomposing the received signal into a first part and a second part, and acquiring signal characteristics of the first part of the received signal and signal characteristics of the second part of the received signal; The third acquisition terminal obtains the signal feature of the transmission signal of the signal from the feature frame, obtains the signal feature of the transmission end signal that is the same as the signal feature of the transmission signal, and obtains the first distance function F11(D) and the second distance function F21(D) corresponding to the feature value of the signal feature; Obtain the characteristic value y1 of the signal characteristic of the transmitted signal and the characteristic value n21 of the signal characteristic of the first part of the received signal, calculate w1, w1=y1-n21, solve the equation w1=F11(D) to obtain the first distance reference value h1, obtain the characteristic value n22 of the signal characteristic of the second part of the received signal, solve the equation n22=F21(D) to obtain the second distance reference value h2.

6. The ad hoc network acoustic emission collection system according to claim 5, characterized in that: The process of the system executing to determine whether the clocks of the first acquisition terminal and the third acquisition terminal are synchronized is as follows: The average value of the signal-to-noise ratio of the received signal is recorded as SNR, and the function G is calculated by the coefficient. The calculation result of the function is recorded as the distance evaluation coefficient α, where k and c represent different parameters respectively; Calculate the reference distance L, L = α × h1 + β × h2, where β = 1-α; Set the signal transmission speed value cv and calculate the transmission time t tran , t tran =L / cv; A difference threshold p is set, and T3-T1=δ is calculated. When |δ|>p, the clock of the first acquisition terminal is not synchronized with the clock of the third acquisition terminal.

7. A self-organizing network acoustic emission collection device, used to implement the self-organizing network acoustic emission collection system according to any one of claims 1 to 6, characterized in that: The acquisition device includes: a preprocessing module, a fault processing module, a feature frame management module, a signal feature processing module and an evaluation and judgment module, wherein the preprocessing module is used to preprocess the historical transmission information of the acquisition device, the fault processing module is used to handle the network connection fault, the feature frame management module is used to manage the feature frames inserted after the cached data, the signal feature processing module is used to analyze the feature frames and the received signals to calculate the distance reference value, and the evaluation and judgment module calculates the reference record and determines whether the clock of the acquisition device is synchronized.

8. The ad hoc network acoustic emission collection device according to claim 7, characterized in that: The preprocessing module includes: a historical data management unit, a feature management unit and a distance function management unit, wherein the historical data management unit is used to collect historical transmission records of the device, the feature management unit is used to obtain signal characteristics of the transmission signal, and the distance function management unit is used to manage the first distance function and the second distance function; The fault handling module includes: a network detection unit, a cache management unit and a networking period management unit, wherein the network detection unit is used to detect the network connection quality between collection devices, the cache management unit is used to cache the data collected by the collection devices, and the networking period management unit is used to manage the networking period between collection devices.

9. The ad hoc network acoustic emission collection device according to claim 7, characterized in that: The signal feature processing module includes: a signal decomposition unit, a feature frame parsing unit and a distance analysis unit, wherein the signal decomposition unit is used to decompose the received signal, the feature frame parsing unit is used to obtain information from the feature frame, and the distance analysis unit is used to calculate the first distance reference value and the second distance reference value respectively through the first distance function and the second distance function.

10. The ad hoc network acoustic emission collection device according to claim 7, characterized in that: The evaluation and judgment module includes: a distance evaluation coefficient calculation unit, a reference distance calculation unit and a time evaluation unit, wherein the distance evaluation coefficient calculation unit is used to calculate the distance evaluation coefficient through a coefficient calculation function, the reference distance calculation unit is used to calculate the reference distance, and the time evaluation unit is used to evaluate whether the clock of the acquisition device is synchronized.

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