阅读说明：本技术 一种基于声阵列的采煤机精确定位系统及其方法 (Accurate positioning system and method for coal mining machine based on acoustic array ) 是由 许静 许杰 张忠宇 赵新旭 杨寅威 王忠宾 吴百公 苏贞 李小虎 于 2020-07-24 设计创作，主要内容包括：本发明公开了一种基于声阵列的采煤机精确定位系统及其方法,包括处于综采工作面环网中的采煤机机载控制器、主动式声发射装置、安装在综采工作面进风侧端头的声音传感器阵列、计算处理装置。其声发射装置主动发出声固定波形与频段的声音信号,其频率尽量避免工作面其他设备发出声音的主要区间。机载控制器隔一段时间给声发射装置一个指令。声音传感器阵列包括3个空间分布的声音传感器,通过盲源分离算法分离出声发射装置发出的信号,根据每个传感器接收到的信号的时间差计算出声发射装置的位置,从而获取采煤机空间位置,实现其精确定位。本发明结构简单,体积小,功耗低,成本低,易于安装布置与维护。(The invention discloses an acoustic array-based accurate positioning system and method for a coal mining machine. The sound emission device actively emits sound signals with fixed waveforms and frequency bands, and the frequency of the sound emission device avoids main intervals in which other devices on a working face make sounds as much as possible. The onboard controller gives an instruction to the acoustic emission device at intervals. The sound sensor array comprises 3 sound sensors distributed in space, signals sent by the sound emission device are separated through a blind source separation algorithm, and the position of the sound emission device is calculated according to the time difference of the signals received by each sensor, so that the space position of the coal mining machine is obtained, and the accurate positioning of the coal mining machine is realized. The invention has the advantages of simple structure, small volume, low power consumption, low cost and easy installation, arrangement and maintenance.)

1. The accurate positioning system of the coal mining machine based on the acoustic array is characterized by comprising a fully-mechanized coal mining face coal mining machine, a coal mining machine onboard controller, an active acoustic emission device, an acoustic sensor array and a calculation processing device, wherein the fully-mechanized coal mining face coal mining machine, the coal mining machine onboard controller, the active acoustic emission device, the acoustic sensor array and the calculation processing device are connected with a ring network of a fully-mechanized coal mining face through communication modules in a mutual communication mode;

the active acoustic emission device is connected with the onboard controller of the coal mining machine and is connected into a fully mechanized coal mining face looped network; the coal mining machine onboard controller is used for giving an instruction to the active acoustic emission device every interval time T and controlling the active acoustic emission device to emit an acoustic signal with a specified waveform;

the sound sensor array comprises 3 sound sensors which are distributed in space; the 3 sound sensors are arranged on the periphery of the computing processing device, and the spatial distribution positions of the sound sensors are not in the same straight line; the sound sensor is used for receiving sound signals emitted by the active sound emitting device and receiving operation sound signals and noise signals of other equipment on the fully mechanized coal mining face;

the device comprises a core processor for data online analysis and calculation, a data memory for data archiving and parameter storage, a synchronous clock circuit for synchronizing clocks of 3 sound sensors, a communication module for communicating with a fully mechanized working face ring network, a signal acquisition module for acquiring and converting signals of the 3 sound sensors, a power supply circuit for power supply, and an intrinsically safe and flameproof shell.

2. The accurate positioning system for the coal mining machine based on the acoustic array is characterized in that the active acoustic emission device is installed on the machine body of the coal mining machine or in an internal explosion-proof cavity of the coal mining machine; when installed on the body of a coal mining machine, the anti-explosion shell and the anti-collision device are correspondingly arranged.

3. The accurate positioning system for the coal mining machine based on the acoustic array as claimed in claim 1, wherein the core processor is a super-miniature calculator based on an SoC platform or an Atom platform.

4. A method for accurately positioning a coal mining machine based on an acoustic array by using the system of any one of claims 1 to 3, wherein the accurate position of the coal mining machine is determined and calculated according to the difference of the time when the waveform of the acoustic signal emitted by the active acoustic emission device reaches 3 acoustic sensors spatially distributed at the periphery of the calculation processing device, and the method comprises the following steps:

step 1, defining a space coordinate system: the coordinate origin is the geometric center point of the calculation processing device, the positive direction of the Z axis is the direction which is vertically upward, the positive direction of the X axis is the direction which faces the coal wall to the right and forms an included angle of 90 degrees with the Z axis, and the positive direction of the Y axis is the direction which is vertical to the XOZ plane and points to the coal wall;

step 2, according to the geometric dimension of the calculation processing device and the spatial arrangement of the 3 sound sensors, the spatial positions of the 3 sound sensors are respectively (x1, y1, z1), (x2, y2, z2), (x3, y3, z 3);

step 3, the active acoustic emission device emits an acoustic signal, a control instruction is emitted by an onboard controller of the coal mining machine, and the acoustic signal needs to avoid frequency intervals of sounds emitted by the coal mining machine of the fully mechanized mining face and other equipment as much as possible; separating a signal waveform emitted by an acoustic active emission device according to the characteristics of an acoustic signal emitted by a fully mechanized mining face coal mining machine and other equipment in the running process and an acoustic signal emitted by the active emission device, which are known in advance, and by combining an acoustic source separation algorithm;

step 4, after the computing and processing device is started, the computing and processing device continuously receives the sound signals of the fully mechanized mining face collected by the 3 sound sensors and carries out analysis and calculation;

step 5, because the 3 sound sensors are distributed in space, the distances from the active sound emission device to each sound sensor are different; according to the 3 channel separation results, the time difference between the starting time point of the signal separated from each channel and the time point of 0 is respectively marked as t1, t2 and t3, the propagation speed of the sound signal is constant c, and the spatial coordinate calculation formula of the active acoustic emission device is as follows:

wherein the content of the first and second substances,

step 6, solving a geometric central point, namely a spatial position (xL, yL, zL) of the active acoustic emission device according to the 3 mutually independent equations in the step 5; finally, the spatial position (xc, yc, zc) of the extraction machine can be determined from the position and geometry of the active acoustic emission device and the geometry of the extraction machine.

5. The method for accurately positioning a coal mining machine based on an acoustic array according to claim 4, characterized in that the avoidance of the frequency interval of the sound emitted by the coal mining machine and other equipment on the fully mechanized mining face in the step 3 can be realized by the following steps: collecting sound signals in the operation process of the fully mechanized mining face in advance, acquiring time-frequency characteristics of the signals by using time-frequency analysis software, and counting frequency interval ranges corresponding to main energy in the signals: f 1-f 2, f 3-f 4 and f 5-f 6 …; and synthesizing an independent sound signal, wherein the frequency of the independent sound signal is far away from the interval, and the independent sound signal is not coupled with the sound source signal of the fully mechanized mining face.

6. The method for accurately positioning the coal mining machine based on the acoustic array according to claim 4, wherein the sound signals emitted by the active acoustic emission device in the step 3 can be periodically executed, and the period length is recommended to be about 3-10 seconds; determining factors for the cycle length include: the length of the fully mechanized coal mining face and the traction speed of the coal mining machine.

7. The method for accurately positioning the coal mining machine based on the acoustic array according to claim 4, characterized in that in the step 3, after the onboard controller of the coal mining machine sends out the control instruction, a signal is sent to the calculation processing device through the ring network of the fully mechanized mining face at the same time, and the calculation processing device starts to work; the computing and processing device initializes the clock of the signal acquisition circuit of the sound sensor of the 3 channels and sets the clock as 0 moment.

8. The method for accurately positioning a coal mining machine based on an acoustic array according to claim 4, wherein the signal sampling frequency of the acoustic sensor and the matched signal acquisition module is at least not less than 2 times of the maximum frequency of an acoustic signal emitted by the active acoustic emission device, so as to ensure the sampling precision and avoid signal aliasing.

Technical Field

The invention belongs to the technical field of accurate positioning of coal mining machines on a coal mine fully mechanized mining face, and relates to an accurate positioning system and method of a coal mining machine based on an acoustic array.

Background

With the development of coal mining technology, the automation and intelligence degree of modern mines are greatly improved, and the progress of coal mining without humanization or with less humanization is promoted. The coal mining machine is one of key devices of a comprehensive mechanical coal mining working face (called a fully mechanized working face for short), and the automation and the intelligent degree of the coal mining machine greatly restrict the coal mining level. The accurate positioning technology of the coal mining machine, namely, the accurate identification of the position of the coal mining machine on the fully mechanized coal mining face at present is a well-recognized technical difficulty and development bottleneck in the coal mining field at home and abroad.

Because the fully mechanized mining face is in the continuous pushing process, the coal mining machine continuously moves along the scraper conveyor, and the environment of the fully mechanized mining face is severe, the traditional positioning method cannot meet the requirement of accurate positioning of the coal mining machine. The shaft encoder positioning method and the inertial navigation positioning method are small in size and easy to install and arrange, but the problem that accumulated errors are difficult to eliminate exists in the using process, and a certain positioning error exists; the infrared positioning method and the laser positioning method need to emit light beams, the precision is higher in a wide space with better illumination conditions, however, the space in the fully mechanized mining face is narrow, the number of devices is large, the working face is not a straight space, and the beam emitting device and the beam receiving device are easily shielded, so that the positioning effect is influenced; the ultrasonic positioning method carries out positioning according to the time difference principle between different receiving devices of a transmitting signal channel, but the ultrasonic transmitting and receiving devices are large in size, high in power consumption and cost and not beneficial to popularization and use.

The Chinese patent application CN201810794991.3 discloses a coal mining machine positioning method based on array type inertia units, wherein four inertia sensing units are arranged above a box body of a coal mining machine, angular acceleration and acceleration data of the coal mining machine are sensed in real time, and positioning of the coal mining machine is realized through a series of algorithms such as denoising, fusion resolving, error correction and the like. Although the method is simple in structure, the problem of accumulated errors inevitably exists in the inertial sensing unit in the actual use process, the positioning accuracy is influenced, and the resolving process in the method is too complex, so that real-time positioning is difficult to realize.

The chinese patent application cn201320089433.x discloses a positioning and monitoring device for a coal mining machine, which is used for realizing position measurement and calculation of the coal mining machine by arranging a monitor device below every three hydraulic supports on a fully mechanized mining face. The method can only obtain the approximate position of the coal mining machine, and the position measurement of the coal mining machine cannot be realized at the blind area position due to the discontinuous arrangement of the monitor.

Disclosure of Invention

The invention aims to overcome the defects of the prior art and provides an accurate positioning system and method of a coal mining machine based on an acoustic array, which are not influenced by the space of a fully mechanized mining face and shielding of other equipment and are not influenced by particles and gases such as dust, gas and the like on the working face; and the positioning results of every two times are mutually independent, the problem of accumulated error does not exist in the positioning process, the power consumption is low, the positioning precision is high, the method is suitable for various geological conditions, and the application range is wide.

In order to solve the above problems, the present invention adopts the following technical solutions.

The invention discloses an accurate positioning system of a coal mining machine based on an acoustic array, which comprises the coal mining machine of a fully mechanized mining face, an onboard controller of the coal mining machine, an active acoustic emission device arranged on the coal mining machine, an acoustic sensor array arranged at the air inlet side end of the fully mechanized mining face and a calculation processing device matched with the acoustic sensor array, wherein the coal mining machine of the fully mechanized mining face is connected with a looped network of the fully mechanized mining face in a mutual communication manner through a communication module;

the active acoustic emission device is connected with the onboard controller of the coal mining machine and is connected into a fully mechanized coal mining face looped network; the coal mining machine onboard controller is used for giving an instruction to the active acoustic emission device every interval time T and controlling the active acoustic emission device to emit an acoustic signal with a specified waveform;

the sound sensor array comprises 3 sound sensors which are distributed in space; the 3 sound sensors are arranged on the periphery of the computing processing device, and the spatial distribution positions of the sound sensors are not in the same straight line; the sound sensor is used for receiving sound signals emitted by the active sound emitting device and receiving operation sound signals and noise signals of other equipment on the fully mechanized coal mining face;

the device comprises a core processor for data online analysis and calculation, a data memory for data archiving and parameter storage, a synchronous clock circuit for synchronizing clocks of 3 sound sensors, a communication module for communicating with a fully mechanized working face ring network, a signal acquisition module for acquiring and converting signals of the 3 sound sensors, a power supply circuit for power supply, and an intrinsically safe and flameproof shell.

Furthermore, the active acoustic emission device is arranged on the body of the coal mining machine or in an explosion-proof cavity inside the coal mining machine; when installed on the body of a coal mining machine, the anti-explosion shell and the anti-collision device are correspondingly arranged.

Preferably, the core processor is a pico-microcomputer based on an SoC platform or an Atom platform.

The invention discloses an accurate positioning method of a coal mining machine based on an acoustic array, which is used for measuring and calculating the accurate position of the coal mining machine according to the difference of the time when the waveform of an acoustic signal emitted by an active acoustic emission device reaches 3 acoustic sensors spatially distributed on the periphery of a calculation processing device, and comprises the following steps:

step 1, defining a space coordinate system: the coordinate origin is the geometric center point of the calculation processing device, the positive direction of the Z axis is the direction which is vertically upward, the positive direction of the X axis is the direction which faces the coal wall to the right and forms an included angle of 90 degrees with the Z axis, and the positive direction of the Y axis is the direction which is vertical to the XOZ plane and points to the coal wall;

step 2, according to the geometric dimension of the calculation processing device and the spatial arrangement of the 3 sound sensors, the spatial positions of the 3 sound sensors are respectively (x1, y1, z1), (x2, y2, z2), (x3, y3, z 3);

step 3, the active acoustic emission device emits an acoustic signal, a control instruction is emitted by an onboard controller of the coal mining machine, and the acoustic signal needs to avoid frequency intervals of sounds emitted by the coal mining machine of the fully mechanized mining face and other equipment as much as possible; separating a signal waveform emitted by an acoustic active emission device according to the characteristics of an acoustic signal emitted by a fully mechanized mining face coal mining machine and other equipment in the running process and an acoustic signal emitted by the active emission device, which are known in advance, and by combining an acoustic source separation algorithm;

step 4, after the computing and processing device is started, the computing and processing device continuously receives the sound signals of the fully mechanized mining face collected by the 3 sound sensors and carries out analysis and calculation;

step 5, because the 3 sound sensors are distributed in space, the distances from the active sound emission device to each sound sensor are different; according to the 3 channel separation results, the time difference between the starting time point of the signal separated from each channel and the time point of 0 is respectively marked as t1, t2 and t3, the propagation speed of the sound signal is constant c, and the spatial coordinate calculation formula of the active acoustic emission device is as follows:

wherein the content of the first and second substances,

step 6, solving a geometric central point, namely a spatial position (xL, yL, zL) of the active acoustic emission device according to the 3 mutually independent equations in the step 5; finally, the spatial position (xc, yc, zc) of the extraction machine can be determined from the position and geometry of the active acoustic emission device and the geometry of the extraction machine.

Further, the frequency interval avoiding the sound emitted by the fully mechanized mining face coal mining machine and other equipment in the step 3 can be realized by the following method: collecting sound signals in the operation process of the fully mechanized mining face in advance, acquiring time-frequency characteristics of the signals by using time-frequency analysis software, and counting frequency interval ranges corresponding to main energy in the signals: f 1-f 2, f 3-f 4 and f 5-f 6 …; and synthesizing an independent sound signal, wherein the frequency of the independent sound signal is far away from the interval, and the independent sound signal is not coupled with the sound source signal of the fully mechanized mining face.

Furthermore, the sound signal emitted by the active sound emission device in the step 3 can be periodically executed, and the suggested value of the period length is about 3-10 seconds; determining factors for the cycle length include: the length of the fully mechanized coal mining face and the traction speed of the coal mining machine.

Further, in step 3, after the onboard controller of the coal mining machine sends out a control instruction, a signal is sent to the calculation processing device through the fully mechanized mining face ring network at the same time, and the calculation processing device starts to work; the computing and processing device initializes the clock of the signal acquisition circuit of the sound sensor of the 3 channels and sets the clock as 0 moment.

Furthermore, the signal sampling frequency of the sound sensor and the matched signal acquisition module is at least not less than 2 times of the maximum frequency of the sound signal emitted by the active sound emission device, so that the sampling precision is ensured, and the signal aliasing is avoided.

Compared with the prior art, the invention has the following beneficial effects and advantages:

(1) the accurate positioning system of the coal mining machine provided by the invention has the advantages of simple structure, small volume of the active acoustic emission device, the acoustic sensor array and the calculation processing device, low power consumption, low cost and easy installation, arrangement and maintenance.

(2) According to the invention, through the appointed sound signals emitted by the active sound emission device arranged on the body of the coal mining machine, the time difference of 3 sound sensors in spatial distribution is different, and the accurate calculation of the spatial position of the coal mining machine is realized.

(3) The accurate positioning method of the coal mining machine based on the acoustic array is not influenced by the space of a fully mechanized mining face and shielding of other equipment, and is not influenced by particles and gases such as dust, gas and the like on the working face. And the positioning results of every two times are mutually independent, the problem of accumulated error does not exist in the positioning process, the power consumption is low, the positioning precision is high, the method is suitable for various geological conditions, and the application range is wide.

(4) The positioning method has the advantages of simple and quick resolving process, easy improvement of the real-time performance of the system and effective reduction of the configuration requirement of the system hardware.

Drawings

FIG. 1 is a system block diagram of one embodiment of the present invention.

Fig. 2 is a schematic diagram of an acoustic sensor array arrangement according to an embodiment of the present invention.

FIG. 3 is a method flow diagram of one embodiment of the present invention.

Detailed Description

The invention discloses an accurate positioning system of a coal mining machine based on an acoustic array, which comprises the coal mining machine of a fully mechanized mining face, an onboard controller of the coal mining machine, an active acoustic emission device arranged on the coal mining machine, an acoustic sensor array arranged at the air inlet side end of the fully mechanized mining face and a calculation processing device matched with the acoustic sensor array, wherein the coal mining machine of the fully mechanized mining face is mutually communicated and connected with a ring network of the fully mechanized mining face through a communication module.

The active acoustic emission device is connected with the onboard controller of the coal mining machine and is connected into a fully mechanized coal mining face looped network; the onboard controller of the coal mining machine is used for giving an instruction to the active acoustic emission device every interval time T and controlling the active acoustic emission device to emit an acoustic signal with a specified waveform. Furthermore, the active acoustic emission device is arranged on the body of the coal mining machine or in an explosion-proof cavity inside the coal mining machine; when installed on the body of a coal mining machine, the anti-explosion shell and the anti-collision device are correspondingly arranged.

The sound sensor array comprises 3 sound sensors which are distributed in space; the 3 sound sensors are arranged on the periphery of the computing processing device, and the spatial distribution positions of the sound sensors are not in the same straight line; the sound sensor is used for receiving sound signals emitted by the active sound emitting device and receiving running sound signals and noise signals of other equipment of the fully mechanized mining face.

The device comprises a core processor for data online analysis and calculation, a data memory for data archiving and parameter storage, a synchronous clock circuit for synchronizing clocks of 3 sound sensors, a communication module for communicating with a fully mechanized working face ring network, a signal acquisition module for acquiring and converting signals of the 3 sound sensors, a power supply circuit for power supply, and an intrinsically safe and flameproof shell. Preferably, the core processor is a pico-microcomputer based on an SoC platform or an Atom platform.

The invention discloses an accurate positioning method of a coal mining machine based on an acoustic array, which is used for measuring and calculating the accurate position of the coal mining machine according to the difference of the time when the waveform of an acoustic signal emitted by an active acoustic emission device reaches 3 acoustic sensors spatially distributed on the periphery of a calculation processing device, and comprises the following steps:

step 1, defining a space coordinate system: the coordinate origin is the geometric center point of the calculation processing device, the positive direction of the Z axis is the direction which is vertically upward, the positive direction of the X axis is the direction which faces the coal wall to the right and forms an included angle of 90 degrees with the Z axis, and the positive direction of the Y axis is the direction which is vertical to the XOZ plane and points to the coal wall;

step 2, according to the geometric dimension of the calculation processing device and the spatial arrangement of the 3 sound sensors, the spatial positions of the 3 sound sensors are respectively (x1, y1, z1), (x2, y2, z2), (x3, y3, z 3);

step 3, the active acoustic emission device emits an acoustic signal, a control instruction is emitted by an onboard controller of the coal mining machine, and the acoustic signal needs to avoid frequency intervals of sounds emitted by the coal mining machine of the fully mechanized mining face and other equipment as much as possible; and separating the signal waveform emitted by the active acoustic emission device by combining an acoustic source separation algorithm according to the characteristics of the acoustic signal emitted by the fully mechanized mining face coal mining machine and other equipment in the running process and the acoustic signal emitted by the active acoustic emission device which are known in advance.

In step 3, the frequency interval avoiding the sound emitted by the fully mechanized mining face coal mining machine and other equipment can be realized by the following method: collecting sound signals in the operation process of the fully mechanized mining face in advance, acquiring time-frequency characteristics of the signals by using time-frequency analysis software, and counting frequency interval ranges corresponding to main energy in the signals: f 1-f 2, f 3-f 4 and f 5-f 6 …; and synthesizing an independent sound signal, wherein the frequency of the independent sound signal is far away from the interval, and the independent sound signal is not coupled with the sound source signal of the fully mechanized mining face. The sound signals emitted by the active sound emission device can be periodically executed, and the suggested value of the period length is about 3-10 seconds; determining factors for the cycle length include: the length of the fully mechanized coal mining face and the traction speed of the coal mining machine. After the onboard controller of the coal mining machine sends a control instruction, a signal is sent to the computing processing device through the fully mechanized mining face looped network at the same time, and the computing processing device starts to work; the computing and processing device initializes the clock of the signal acquisition circuit of the sound sensor of the 3 channels and sets the clock as 0 moment.

Step 4, after the computing and processing device is started, the computing and processing device continuously receives the sound signals of the fully mechanized mining face collected by the 3 sound sensors and carries out analysis and calculation;

step 5, because the 3 sound sensors are distributed in space, the distances from the active sound emission device to each sound sensor are different; according to the 3 channel separation results, the time difference between the starting time point of the signal separated from each channel and the time point of 0 is respectively marked as t1, t2 and t3, the propagation speed of the sound signal is constant c, and the spatial coordinate calculation formula of the active acoustic emission device is as follows:

wherein the content of the first and second substances,

step 6, solving a geometric central point, namely a spatial position (xL, yL, zL) of the active acoustic emission device according to the 3 mutually independent equations in the step 5; finally, the spatial position (xc, yc, zc) of the extraction machine can be determined from the position and geometry of the active acoustic emission device and the geometry of the extraction machine.

Furthermore, the signal sampling frequency of the sound sensor and the matched signal acquisition module is at least not less than 2 times of the maximum frequency of the sound signal emitted by the active sound emission device, so that the sampling precision is ensured, and the signal aliasing is avoided.

The present invention will be described in further detail with reference to the accompanying drawings.

FIG. 1 is a system block diagram of one embodiment of the present invention. As shown in fig. 1. The system comprises a fully mechanized coal mining face coal mining machine, an onboard controller of the fully mechanized coal mining face coal mining machine, an active acoustic emission device arranged on the coal mining machine, an acoustic sensor array arranged at the end head of the air inlet side of the fully mechanized coal mining face, a calculation processing device matched with the acoustic sensor array, and the like.

The active acoustic emission device is arranged on the body of the coal mining machine or in an explosion-proof cavity inside the coal mining machine, and if the active acoustic emission device is arranged on the body of the coal mining machine, the active acoustic emission device is provided with a corresponding explosion-proof shell and a corresponding anti-collision device.

And the active acoustic emission device is connected with the onboard controller of the coal mining machine and is connected into a fully mechanized coal mining face looped network. The onboard controller of the coal mining machine gives an instruction to the active acoustic emission device at a time interval T to control the active acoustic emission device to send out an acoustic signal with a specified waveform.

The value of T can be roughly determined according to factors such as the length of the fully mechanized mining face, the traction speed of the coal mining machine and the like, and the value is generally recommended to be about 3-10 seconds.

Fig. 2 is a schematic diagram of an acoustic sensor array arrangement according to an embodiment of the present invention. As shown in fig. 2, the acoustic sensor array is composed of 3 industrial-grade dustproof microphones distributed spatially, and is configured to receive acoustic signals emitted by the active acoustic emission device, and receive acoustic signals of other devices in the fully mechanized mining face during operation, as well as noise signals. The sound sensors are distributed in space, are not on the same straight line and are arranged beside the calculation processing device.

The device comprises a core processor for data online analysis and calculation, a data memory for data filing and parameter storage, a synchronous clock circuit for synchronizing clocks of 3 sound sensors, a communication module for communicating with a fully mechanized coal face ring network, a signal acquisition module for acquiring and converting 3 sound sensor signals, a power supply circuit for supplying power to the device and an intrinsic safety and explosion-proof shell of the device.

The core processor is a ultramicro calculator based on an SoC platform or an Atom platform. The communication module and the fully mechanized coal mining face ring network can be connected in a wireless mode such as wireless WiFi, wireless MESH and wireless Zigbee, or in a wired mode such as a mining flame-retardant network cable, a shielding twisted pair and a power carrier cable.

The signal sampling frequency of the sound sensor and the matched signal acquisition module is at least 2 times of the maximum frequency of the sound signal emitted by the active sound emission device, so that the sampling precision is ensured, and the signal aliasing is avoided.

The computing processing device is mostly in a low-power-consumption standby state, and only after receiving a running starting signal sent by the onboard controller of the coal mining machine, the computing processing device starts to work so as to reduce the power consumption of the system.

The accurate positioning system of the coal mining machine provided by the invention has the advantages of simple structure, small volume of the active acoustic emission device, the acoustic sensor array and the calculation processing device, low power consumption, low cost and easy installation, arrangement and maintenance.

FIG. 3 is a method flow diagram of one embodiment of the present invention. As shown in fig. 3, the method of this embodiment of the present invention is obtained by using different calculations of the time when the waveform of the sound signal emitted by the active sound emission device reaches 3 spatially distributed sound sensors. The specific implementation steps and processes are as follows:

step 1, defining a space coordinate system: the origin of coordinates is the geometric center point of the calculation processing device, the positive direction of the Z axis is the direction which is vertically upward, the positive direction of the X axis is the direction which faces the coal wall to the right and forms an included angle of 90 degrees with the Z axis, and the positive direction of the Y axis is the direction which is vertical to the XOZ plane and points to the coal wall.

Step 2, according to the geometric dimension of the calculation processing device and the spatial arrangement of the sound sensors, the spatial positions of 3 sound sensors can be obtained, wherein the spatial positions are (x) respectively₁,y₁,z₁)、(x₂,y₂,z₂)、(x₃,y₃,z₃)。

And 3, the active acoustic emission device emits an acoustic signal, the control instruction is emitted by an onboard controller of the coal mining machine, and the acoustic signal avoids frequency intervals of sounds emitted by the coal mining machine of the fully mechanized mining face and other equipment as much as possible.

And 4, after the calculation processing device starts to work, receiving the sound signals of the fully mechanized coal mining face collected by the 3 sound sensors all the time, and analyzing and calculating the sound signals.

And 5, because the 3 sound sensors are distributed in space, the distances from the active sound emission device to each sound sensor are different. According to the separation results of 3 channels, the time difference between the initial time point of the signal separated by each channel and the time point of 0 is respectively marked as t₁，t₂，t₃The propagation speed of the sound signal is constant c. The spatial coordinate calculation formula of the active sound emission device is as follows:

wherein the content of the first and second substances,

step 6, the 3 mutually independent equations can solve the space position (x) of the active acoustic emission device_L,y_L,z_L) And the calculation result is unique. Finally, according to the installation position and the geometric dimension of the active acoustic emission device and the geometric dimension of the coal mining machine, the spatial position (x) of the coal mining machine can be obtained_c,y_c,z_c)。

In step 2, the geometric center points of the sound sensor and the active sound emission device are adopted to represent the spatial position of the equipment, and the position of the active sound emission device is defined as (x)_L,y_L,z_L) And is an unknown solution quantity, as shown in fig. 2.

Avoiding the coal mining machine and other equipment on the fully mechanized mining face in the step 3The frequency interval of the sound can be realized by the following steps: collecting sound signals in the running process of the fully mechanized mining face in advance, acquiring time-frequency characteristics of the signals by using time-frequency analysis software, and counting frequency interval ranges such as f corresponding to main energy in the signals₁～f₂，f₃～f₄，f₅～f₆…, respectively; and synthesizing an independent sound signal, wherein the frequency of the independent sound signal is far away from the interval, and the independent sound signal is not coupled with the sound source signal of the fully mechanized mining face.

In addition, the sound signals emitted by the active sound emitting device in the step 3 can be periodically executed, the period length can be roughly determined according to the length of the fully mechanized mining face, the traction speed of the coal mining machine and other factors, and the value is generally recommended to be about 3-10 seconds.

And simultaneously, after the onboard controller of the coal mining machine sends a control instruction in the step 3, a signal is sent to the computing processing device through the fully mechanized working face ring network, and the computing processing device starts to work (the computing processing device is in a low-power-consumption standby running state at other time). The computing and processing device initializes the clock of the signal acquisition circuit of the sound sensor of the 3 channels and sets the clock as 0 moment.

In step 5, according to the previously known sound signals emitted by the fully mechanized mining face coal mining machine and other equipment in the operation process and the characteristics of the sound signals emitted by the active sound emission device, the signal waveform emitted by the active sound emission device is separated by combining a sound source separation algorithm (such as a principal component analysis method, a spatial clustering method, an information theory algorithm and the like).

In a word, the system comprises a fully mechanized coal mining face coal mining machine and an onboard controller thereof, an active acoustic emission device arranged on the coal mining machine, an acoustic sensor array arranged at the end head of the air inlet side of the fully mechanized coal mining face, a calculation processing device matched with the acoustic sensor array, and the like, and the system achieves the difference of time differences of 3 acoustic sensors in spatial distribution through specified acoustic signals emitted by the active acoustic emission device arranged on the body of the coal mining machine, thereby realizing the accurate calculation of the spatial position of the coal mining machine. The system has the advantages of simple structure, small volume, low power consumption, low cost and easy installation, arrangement and maintenance. In the method, the active sound emitting device actively emits sound signals with fixed waveforms and frequency bands, and the emitted sound frequency avoids the main interval of other equipment on the working surface emitting sound as much as possible. The active acoustic emission device is connected with the onboard controller of the coal mining machine and is connected into a fully mechanized coal mining face looped network. The onboard controller of the coal mining machine gives an instruction to the active acoustic emission device at intervals to control the active acoustic emission device to emit specified sound. The sound sensor array consists of 3 sound sensors distributed in space, signals sent by the sound emission device are separated through a blind source separation algorithm, and the position of the active sound emission device is calculated according to the time difference of the signals received by each sensor, so that the space position of the coal mining machine is obtained, and the accurate positioning of the coal mining machine is realized. The method is not influenced by the space of the fully mechanized mining face and the shielding of other equipment, and is not influenced by particles such as dust, gas and the like on the working face and gas. And the positioning results of every two times are mutually independent, the problem of accumulated error does not exist in the positioning process, the power consumption is low, the positioning precision is high, the method is suitable for various geological conditions, and the application range is wide.