阅读说明：本技术 一种基于随机传感器网络的声发射源定位方法和系统 (Acoustic emission source positioning method and system based on random sensor network ) 是由 周子龙 芮艺超 周静 蔡鑫 程瑞山 董陇军 于 2019-09-29 设计创作，主要内容包括：本发明公开了一种基于随机传感器网络的声发射源定位方法和系统,所述随机传感器网络包括在监测系统中任意位置、不全部共面布置的n个声发射传感器,其中n≥6；将n个声发射传感器的坐标记为(x<Sub>i</Sub>,y<Sub>i</Sub>,z<Sub>i</Sub>),i＝1,2,…,n；记录n个声发射传感器接收到声发射信号的时间,分别记为t<Sub>1</Sub>,t<Sub>2</Sub>,…,t<Sub>n</Sub>；根据给出的定位公式计算声发射源坐标(x,y,z)。本发明能实现较高定位精度和稳定性。(the invention discloses an acoustic emission source positioning method and system based on a random sensor network, wherein the random sensor network comprises n acoustic emission sensors which are not completely arranged in a coplanar manner at any position in a monitoring system, wherein n is more than or equal to 6; the coordinates of the n acoustic emission sensors are recorded as (xi, yi, zi), i is 1,2, …, n; recording the time of the n acoustic emission sensors receiving the acoustic emission signals, and recording the time as t1, t2, … and tn respectively; the acoustic emission source coordinates (x, y, z) are calculated according to a given localization formula. The invention can realize higher positioning precision and stability.)

1. a sound emission source positioning method based on a random sensor network is characterized in that the random sensor network comprises n sound emission sensors which are not completely arranged in a coplanar manner at any position in a monitoring system, wherein n is more than or equal to 6;

The coordinates of the n acoustic emission sensors are recorded as (xi, yi, zi), i is 1,2, …, n;

recording the time of the n acoustic emission sensors receiving the acoustic emission signals, and recording the time as t1, t2, … and tn respectively;

And calculating the coordinates (x, y, z) of the acoustic emission source according to the following formula to realize the positioning of the acoustic emission source:

wherein the content of the first and second substances,

Wherein r1-r 32, a 1-a 5, a 1-a 5, b 1-b 5, c 1-c 5, d 1-d 5, e 1-e 5 and f 1-f 5 are intermediate variables.

2. an acoustic emission source positioning system based on a random sensor network is characterized by comprising a data processing module; the data processing module uses the localization method of claim 1 to calculate the coordinates (x, y, z) of the acoustic emission source based on the coordinates of each acoustic emission sensor in the random sensor network and the time they received the acoustic emission signal, and to achieve localization of the acoustic emission source.

3. A stochastic sensor network based acoustic emission source localization system according to claim 2, further comprising the stochastic sensor network.

Technical Field

the invention relates to an acoustic emission source positioning method and system based on a random sensor network.

background

The acoustic emission positioning technology is widely applied to the research of the cracking and destabilizing mechanism of materials such as rocks, concrete and the like, and a main and basic step of analyzing and researching acoustic emission is to identify the position where damage and damage occur, so that an accurate acoustic emission source positioning method is of great importance. In order to improve the positioning accuracy of the acoustic emission source, researchers have proposed a number of positioning methods for a long time. However, most positioning methods require the wave velocity to be measured in advance, and wave velocity measurement errors are inevitable. Practical application shows that the wave velocity measurement value is greatly influenced by the sensor spacing, and a small change of the sensor spacing can cause a large change of the wave velocity measurement value. In the process of material damage testing, the path of an acoustic emission signal from a source position to a sensor can be changed continuously in the testing process, so that the average wave speed is changed. In addition, in dynamic mining environments such as mining operations, the location of the rock burst is not necessarily in the area where the wave velocity is measured ahead of time, and the average wave velocities at different times are not equal. Therefore, the previously measured wave velocity often has a large deviation from the true wave velocity, and finally, a large error is generated in the positioning result.

for this reason, patent CN102129063A discloses a method for positioning a micro seismic source or an acoustic source, which belongs to an iterative positioning method, and has low operation efficiency and needs to preset an initial value, so that there are cases of iterative divergence and non-convergence. Patent CN102435980A discloses an acoustic emission source or micro seismic source positioning method based on analytic solution, which has high calculation efficiency, but the method is only suitable for the problem of positioning an acoustic emission source with a fixed geometric shape, and a sensor needs to be placed at a specific position. CN102590790A discloses a non-iterative positioning algorithm for jointly solving velocity and target position, which can be used for positioning acoustic emission targets under the condition of unknown propagation velocity and can comprehensively utilize all sensors, but this method needs to solve a cubic equation of a single element about wave velocity in advance, and the positioning result of the acoustic emission source will be seriously affected by the conditions of no solution and multiple solutions of wave velocity.

Therefore, further research is still needed for the problem of locating the acoustic emission source of the random sensor network of the unknown wave velocity system.

disclosure of Invention

The invention aims to solve the technical problem of providing an acoustic emission source positioning method and system based on a random sensor network, aiming at the defects of the prior art, wherein the method is easy to realize and has high positioning precision and calculation efficiency.

the technical scheme provided by the invention is as follows:

an acoustic emission source positioning method based on a random sensor network comprises n acoustic emission sensors which are not completely arranged in a coplanar manner at any position in a monitoring system, wherein n is more than or equal to 6;

The coordinates of the n acoustic emission sensors are recorded as (xi, yi, zi), i is 1,2, …, n;

Recording the time of the n acoustic emission sensors receiving the acoustic emission signals, and recording the time as t1, t2, … and tn respectively;

and calculating the coordinates (x, y, z) of the acoustic emission source according to the following formula to realize the positioning of the acoustic emission source:

wherein the content of the first and second substances,

and r1-r 32, a 1-a 5, a 1-a 5, b 1-b 5, c 1-c 5, d 1-d 5, e 1-e 5 and f 1-f 5 are intermediate variables.

the derivation process of the above formula is as follows, and the positioning flow of the method is shown in fig. 1.

Firstly, establishing a distance time formula of an acoustic emission source:

Where t0 is the trigger time of the acoustic emission source signal, v is the medium wave velocity, and both are unknown quantities.

multiplying both sides of the equation by v, then squaring, yields:

(x-x)+(y-y)+(z-z)＝v(t-t),i＝1,2,…,n

subtracting the equation of which i is 1 from the equation of which i is greater than 1 to obtain an acoustic emission source overdetermined linear equation set of an unknown wave velocity system under the random sensor network:

2(xi-x1) x +2(yi-y1) y +2(zi-z1) z + (ti2-t12) V +2(t1-ti) K ═ Li-L1, wherein V ═ V2, K ═ Vt0, Li ═ xi2+ yi2+ zi2, and L1 ═ x12+ y12+ z 12.

because of the inevitable error in the arrival time data, the left side and the right side of the equation cannot be equal, and certain deviation, also called equation residual, exists. The specific expressions of equation residuals η i and the sum of squares γ of the equation residuals are as follows:

η＝2(x-x)x+2(y-y)y+2(z-z)z+(t-t)V+2(t-t)K+L-L

solving the partial derivatives of the equation residual squared sum gamma to the parameters x, y, z, V and K, and making the partial derivatives equal to 0, a positive definite linear equation system containing the sound emission source coordinates x, y and z and the additional variables V and K can be obtained:

wherein the content of the first and second substances,

and

Solving the equation for the fixed equation set, firstly eliminating the unknown item K, and obtaining an equation set only containing four unknown parameters of x, y, z and V:

wherein the content of the first and second substances,

by subsequent elimination of the unknown term V by elimination, the following system of linear equations can be obtained, containing only the acoustic emission source parameters x, y, z:

Wherein the content of the first and second substances,

finally, the coordinates x, y, z of the acoustic emission source can be obtained by solving the three equations:

the invention also provides an acoustic emission source positioning system based on the random sensor network, which comprises a data processing module; the data processing module uses the localization method of claim 1 to calculate the coordinates (x, y, z) of the acoustic emission source based on the coordinates of each acoustic emission sensor in the random sensor network and the time they received the acoustic emission signal, and to achieve localization of the acoustic emission source.

Further, the acoustic emission source localization system further comprises the stochastic sensor network.

the invention constructs an over-determined linear equation set of the acoustic emission source according to an acoustic emission distance time formula, and a positive-determined equation set can be obtained by solving the partial derivatives of the equation residual sum of squares and making the partial derivatives equal to zero. Then solving the equation for the fixed equation set to obtain the analytic solution of the optimal sound emission source position. The method does not require the wave velocity to be measured in advance. Compared with the existing unknown wave velocity positioning method, the method can comprehensively utilize all sensor information, and ensure the accuracy of the coordinates of the acoustic emission source from the aspect of statistics. In addition, the method does not need any prior solution, and avoids the situations of no solution, multiple solutions and the like.

Has the advantages that:

The invention provides a simple and convenient new method with higher positioning precision and stability for positioning an acoustic emission source, and the method has the following advantages:

(1) The wave velocity is not required to be measured in advance, so that the influence of wave velocity measurement errors is avoided;

(2) the method belongs to an analytic positioning method, and compared with an iterative positioning method, an iteration initial value is not required to be given, so that the problems of iteration unconvergence and low calculation efficiency are avoided;

(3) the positioning can be carried out based on a random sensor network, the installation positions of the sensors only need more than 6 acoustic emission sensors not to be coplanar at the same time, and each acoustic emission sensor does not need to be installed at a specific position;

(4) By introducing the least square principle, the information of all acoustic emission sensors can be comprehensively utilized for analyzing and positioning, so that the positioning precision is improved;

(5) the prior solution of the wave velocity is not needed, and the situations of no solution and multiple solutions are avoided.

drawings

fig. 1 is a schematic diagram of a positioning method in an embodiment of the present invention.

fig. 2 is a schematic diagram of three-dimensional positioning of an acoustic emission source in a sensor arrangement.

Fig. 3 is a schematic diagram of three-dimensional positioning of an acoustic emission source in another sensor arrangement.

Detailed description of the invention

The present invention will be further described in detail with reference to the drawings and specific examples.