CN112881744A - Train speed and direction measuring device based on train sound and working method thereof - Google Patents
Train speed and direction measuring device based on train sound and working method thereof Download PDFInfo
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01P—MEASURING LINEAR OR ANGULAR SPEED, ACCELERATION, DECELERATION, OR SHOCK; INDICATING PRESENCE, ABSENCE, OR DIRECTION, OF MOVEMENT
- G01P3/00—Measuring linear or angular speed; Measuring differences of linear or angular speeds
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- G—PHYSICS
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- G01P—MEASURING LINEAR OR ANGULAR SPEED, ACCELERATION, DECELERATION, OR SHOCK; INDICATING PRESENCE, ABSENCE, OR DIRECTION, OF MOVEMENT
- G01P13/00—Indicating or recording presence, absence, or direction, of movement
- G01P13/02—Indicating direction only, e.g. by weather vane
Abstract
The invention discloses a train speed and direction measuring device based on train sound, which comprises a first sound sensing module, a second sound sensing module, a first signal regulating module, a second signal regulating module, a first AD sampling module, a second AD sampling module, a DSP module and an interface module, wherein the first sound sensing module, the first signal regulating module, the first AD sampling module, the DSP module and the interface module are sequentially connected in series; the second sound sensing module, the second signal conditioning module, the second AD sampling module, the DSP module and the interface module are sequentially connected in series. The invention can solve the technical problems of large construction amount, long period and high price of the sensor caused by the fact that the existing wired sensor needs to be operated by a buried line construction party, and the technical problems of poor use flexibility and long installation time caused by the fact that the existing radar speed measuring device and the existing laser speed measuring device have higher requirements on installation positions.
Description
Technical Field
The invention belongs to the technical field of railway operation safety, and particularly relates to a train speed and direction measuring device based on train sound and a working method thereof.
Background
Under the rapid development of railway information construction, a train speed and direction measuring device is widely used in a railway alarm system, and is used for judging the distance between a train and constructors and the direction of a coming train and giving an alarm in time so as to prevent railway construction accidents.
The existing train speed measuring device is usually realized by a wired sensor, a radar speed measuring device or a laser speed measuring device, and the train direction measuring device is realized by the combination of a plurality of wired sensors, radar speed measuring devices and laser speed measuring devices.
However, the train distance measuring and speed measuring device has some non-negligible technical problems: firstly, for a wired sensor (such as a magnetic steel sensor), a buried wire construction party is required to be put into operation, the construction quantity is large, the period is long, and the price of the sensor is very expensive; secondly, the radar speed measuring device and the laser speed measuring device can only carry out speed measuring and direction measuring operations under the condition of no obstruction, so that higher requirements are imposed on the installation position, the use flexibility is poor, and the installation process takes long time; thirdly, the radar speed measuring device and the laser speed measuring device have high power consumption and are inconvenient to carry.
Disclosure of Invention
The invention provides a train speed and direction measuring device based on train sound and a working method thereof, aiming at solving the technical problems of large construction amount, long period and high price of a sensor caused by the fact that a traditional wired sensor needs to be put into operation by a buried line construction party, the technical problems of poor use flexibility and long time spent in the installation process caused by high requirements on the installation position of the traditional radar speed measuring device and the traditional laser speed measuring device, and the technical problems of high power consumption and inconvenient carrying of the traditional radar speed measuring device and the traditional laser speed measuring device.
In order to achieve the above object, according to one aspect of the present invention, there is provided a train speed and direction measuring device based on train sound, comprising a first sound sensing module, a second sound sensing module, a first signal conditioning module, a second signal conditioning module, a first AD sampling module, a second AD sampling module, a DSP module, and an interface module, wherein the first sound sensing module, the first signal conditioning module, the first AD sampling module, the DSP module, and the interface module are sequentially connected in series;
the second sound sensing module, the second signal conditioning module, the second AD sampling module, the DSP module and the interface module are sequentially connected in series.
Preferably, in operation, the first sound sensing module and the second sound sensing module are both arranged parallel to a side rail, and the first sound sensing module and the second sound sensing module are both perpendicular to the side rail, the distance d between the first sound sensing module and the second sound sensing module is 10 cm to 30 cm, preferably 20 cm, and the distance L between the first sound sensing module and the second sound sensing module and the side rail is 10m to 50m, preferably 30 m.
Preferably, the first sound sensing module and the second sound sensing module are completely the same and both adopt KY-037 type sound sensors;
the first signal conditioning module and the second signal conditioning module are completely the same and respectively comprise a preceding-stage amplification circuit, a low-pass filter circuit and a subsequent-stage amplification circuit which are sequentially connected in series. The front-stage amplification circuit and the rear-stage amplification circuit both adopt ADA4625-2 type operational amplifiers; the low-pass filter circuit is a 3-order Butterworth low-pass filter consisting of an ADA4625-2 type operational amplifier, and the 3dB cut-off frequency is 10 kHz;
the first AD sampling module and the second AD sampling module are completely the same and adopt AD4680 type sampling chips;
the model of the DSP module is TMS320C203PZ 80;
the interface module comprises a Lora module and an RS232 serial port module which are connected with each other in series.
In general, the above devices contemplated by the present invention can achieve the following advantages compared to the prior art:
1. the invention utilizes the sound of the train transmitted by air to measure the speed and direction of the train, is not shielded by curves, tunnels and the like, has loose installation position, does not need to enter the railway network, only needs to be near the railway, and can save all cost problems entering the railway network to the greatest extent.
2. The railway track laying device has various use modes, can be fixedly installed and is portable to install, the track laying construction is not needed, only the railway track laying device needs to be fixed at the edge of a railway, and the construction time can be saved to the greatest extent.
3. The invention uses the sound sensor to measure the speed and direction of the train, and has low power consumption and low price.
According to another aspect of the present invention, there is provided a method for operating a train speed and direction measuring device based on train sound, comprising the steps of:
(1) the interface module receives a working instruction from a user and starts the DSP module to start working;
(2) the DSP module closes the second AD sampling module, sets a counter s to be 1, and starts a timer T1 and a timer T2 to start working;
(3) the DSP module controls the first AD sampling module to perform single sampling so as to obtain a plurality of voltage values, and calculates the maximum value q of all the voltage valuesmaxAnd minimum value qminAnd the sum of all voltage values Qsum；
(4) The DSP module judges whether q existsmax<a is true, and q ismin<b is true, and Qsum<c is true; if yes, entering the step (5), otherwise, returning to the step (3); wherein a is a first threshold, b is a second threshold, and c is a third threshold;
(5) the DSP module sets a counter i to be 1;
(6) the DSP module controls the first AD sampling module and the second AD sampling module to respectively carry out single sampling so as to respectively obtain the ith sampling result XiAnd Yi；
(7) The DSP module judges whether the timer T1 is overtime, if yes, i is set to i +1, and the step (8) is carried out, otherwise, the judging process of the step (7) is continued;
(8) the DSP module judges whether i is larger than a preset sampling frequency threshold FRA, if so, the step (9) is carried out, otherwise, the step (6) is carried out; wherein FRA ∈ [3, 10 ].
(9) The DSP module is used for sampling all the sampling results XiAnd YiCalculating corresponding average energy values D1 and D2 respectively;
(10) the DSP module controls the first AD sampling module and the second AD sampling module to respectively carry out single sampling so as to respectively obtain an s-th sampling result AsAnd Bs；
(11) The DSP module respectively calculates sampling results AsAnd BsSum of all voltage values of (1) Sum1sAnd Sum2sAnd judging whether Sum1 existssAnd Sum2sIf the train speed and direction measuring signals are all larger than the preset threshold Th, the train approaches the train speed and direction measuring device based on the train sound and the step (12) is carried out, otherwise, no train approaches the train speed and direction measuring device based on the train sound and the step (17) is carried out;
(12) the DSP module samples the result A of the s timesAnd BsRespectively carrying out discrete Fourier transform to respectively obtain transform results CsAnd DsAnd separately applying spectral subtraction to the transformation result CsAnd DsAre processed to obtain results E respectivelysAnd Fs；
(13) The DSP module respectively processes the results E obtained in the step (12)sAnd FsPerforming discrete Fourier transform to obtain transform results PsAnd QsComputing a transformation result PsAnd QsAnd obtaining the argument h corresponding to the minimum value of the correlation functions；
(14) The DSP module obtains the independent variable h according to the step (13)sAcquiring an included angle INC between a connection line between the centers of mass of a microphone of the first sound sensing module and the mass of a microphone of the second sound sensing module and a railsAnd determining the included angle INCsIf the train direction is less than 90 degrees, sending information that the train direction is from the first sound sensing module to the second sound sensing module to the interface module if the train direction is less than 90 degrees, then entering the step (15), otherwise sending information that the train direction is from the second sound sensing module to the first sound sensing module to the interface module, and entering the step (15);
(15) the DSP module obtains the included angle INC according to the step (14)sObtaining the distance D between the perpendicular projection of the centers of the mass center of the microphone of the first sound sensing module and the mass center of the microphone of the second sound sensing module on the rail and the train obtained in the s-th timesAnd judging whether s is larger than 1, if so, entering the step (16), otherwise, returning to the step (10);
(16) the DSP module obtains the distance D according to the s timesAnd the distance D obtained at the s-1 st times-1Calculating the train speed, sending the calculated train speed to an interface module, and setting s to be s + 1;
(17) the interface module judges whether a sleep instruction from a user is received, if so, the process is ended, otherwise, the step (18) is carried out;
(18) the interface module judges whether an environmental noise updating instruction from a user is received, if so, the user finds that a new noise source exists at the position where the system of the invention is located, and returns to the step (2), otherwise, the user does not find that the new noise source exists at the position where the system of the invention is located, and returns to the step (10);
preferably, in the step (3), the sampling rate is F1 ═ 8KHz, and the single sampling time is Int1 ═ 10 ms;
the value range of the first threshold a is equal to 1/10 times to 1/5 times of the sampling upper limit value of the first AD sampling module;
the value range of the second threshold b is equal to 1/20 times to 1/10 times of the sampling upper limit value of the first AD sampling module;
the third threshold c ranges from 1/12 × F1 × Int1 to 1/8 × F1 × Int1 times the sampling upper limit value of the first AD sampling module.
Preferably, the sampling rate in step (6) and step (10) is F2 ═ 20k, and the single sampling time is Int2 ═ 50 ms;
the timeout period of the timer T1 in step (7) is 500 ms.
Preferably, step (9) is performed using the following equation:
in the step (11), the range of the preset threshold Th is equal to 1/6 × F2 × Int2 times to 1/4 × F2 × Int2 times of the sampling upper limit value of the first AD sampling module.
Preferably, the result E in step (12)s＝|Cs|-a1*D1，Fs＝|DsL-a 1 × D2, wherein a1 represents a weight value, and the value ranges from 0.8 to 1.5, preferably 1.2;
in step (14), the included angle INCsINCs＝arccos(c*hs/(F2*d))
Where c represents the speed of sound and d represents the distance between the center of mass of the microphone in the first sound sensing module and the center of mass of the microphone in the second sound sensing module.
Preferably, the distance Ds＝L/tanINCsWherein L represents the distance from the first sound sensing module and the second sound sensing module to the rail on the side closest to the first sound sensing module and the second sound sensing module;
train speed ═ (D)s-Ds-1) and/T, which is expressed in meters/second, wherein T represents the timeout duration of the timer T2, which takes 500 ms.
In general, the above method contemplated by the present invention can achieve the following advantages compared to the prior art:
(1) according to the invention, the steps (1) to (4) are adopted, the DSP module controls the first AD sampling module to carry out single sampling at a lower sampling rate for a shorter time to obtain the maximum value and the minimum value of a plurality of voltage values, so that pulse interference such as car whistling, bird cry and the like can be prevented, the interference can enable the change range of the plurality of voltage values to be larger, but the sum of the voltage values to be smaller, and meanwhile, the time when the environmental sound changes relatively stably can be found by judging the sum of the plurality of voltage values and can be used as the initial time for extracting the background noise. Compared with the method that the DSP module controls the first AD sampling module to directly calculate and judge whether the voltage values are noise or not by sampling for a single time at a large sampling rate for a long time, the method has the advantages of small calculation amount and higher efficiency, and particularly for the road sections with frequent incoming vehicles, the calculation amount can be greatly reduced.
(2) According to the invention, the steps (5) to (9) are adopted, the DSP module controls the first AD sampling module and the second AD sampling module to respectively carry out multiple sampling to obtain two groups of voltage values, and further the average energy values D1 and D2 in the groups are calculated to be used as the background of the environmental noise, so that the calculation accuracy of the train speed when the train approaches is improved.
(3) As the steps (12) to (13) are adopted, the noise reduction processing is respectively carried out on the signals received by the two paths of sound sensing modules through the spectral subtraction method, and then the time delay between the two paths of signals of the cross-correlation function is utilized to improve the accuracy of time delay calculation and further improve the accuracy of speed calculation.
(4) Because the invention adopts the step (14), the included angle INCS between the connecting line between the centers of the mass centers of the microphone of the train and the first sound sensing module and the mass center of the microphone of the second sound sensing module and the rail is obtained by the independent variable hs obtained in the step (13), and the direction of the train is judged by judging the relation between the included angle and 90 degrees, compared with the joint direction finding of a plurality of sensors, the invention greatly reduces the cost, reduces the power consumption of the system and enhances the portability of the system.
(5) Because the invention adopts the steps (14) to (16), the train speed is calculated according to the geometric relationship between the system installation position and the train position by obtaining the distance Ds obtained in the s-th time, the distance Ds-1 obtained in the s-1-th time and the time delay between the two times of the distances Ds and Ds-1, the speed updating real-time performance is high, the calculated amount is small, and the time delay is low.
(6) Because the invention adopts the step (18), the background of the environmental noise is updated by judging whether the interface module receives the environmental noise updating instruction from the user, and the adaptability of the system to the area with larger environmental change is enhanced.
Drawings
Fig. 1 is a schematic block diagram of a train speed and direction measuring device based on train sound according to the present invention.
Fig. 2 is a flow chart of the working method of the train speed and direction measuring device based on the train sound.
Fig. 3 is a schematic view of the installation position of the train speed and direction measuring device based on the train sound.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention. In addition, the technical features involved in the embodiments of the present invention described below may be combined with each other as long as they do not conflict with each other.
As shown in fig. 1, the present invention provides a train speed and direction measuring device based on train sound, which includes a first sound sensing module 1, a second sound sensing module 2, a first signal conditioning module 3, a second signal conditioning module 4, a first Analog-to-Digital (AD) sampling module 5, a second AD sampling module 6, a Digital Signal Processor (DSP) module 7, and an interface module 8.
The first sound sensing module 1, the first signal conditioning module 3, the first AD sampling module 5, the DSP module 7, and the interface module 8 are sequentially connected in series, and the second sound sensing module 2, the second signal conditioning module 4, the second AD sampling module 6, the DSP module 7, and the interface module 8 are sequentially connected in series.
As shown in fig. 3, when the train sound-based train speed and direction measuring device of the present invention needs to be installed near a rail, the first sound sensing module 1 and the second sound sensing module 2 are both disposed parallel to a side rail, and the microphones in the first sound sensing module 1 and the second sound sensing module 2 are both perpendicular to the side rail, the distance d between the centroid of the microphone in the first sound sensing module 1 and the centroid of the microphone in the second sound sensing module 2 is 10 cm to 30 cm, preferably 20 cm, and the distance L between the first sound sensing module 1 and the second sound sensing module 2 and the side rail is 10 to 50m, preferably 30 m.
Specifically, the first acoustic sensing block 1 and the second acoustic sensing block 2 are identical, and both are KY-037 type acoustic sensors.
The first signal conditioning module 3 and the second signal conditioning module 4 are identical and each include a preceding stage amplification circuit, a low-pass filter circuit, and a subsequent stage amplification circuit connected in series in this order.
The front-stage amplification circuit and the rear-stage amplification circuit both adopt ADA4625-2 type operational amplifiers;
the low-pass filter circuit is a 3-order Butterworth low-pass filter consisting of an ADA4625-2 type operational amplifier, and the 3dB cut-off frequency is 10 kHz;
the first AD sampling module 5 and the second AD sampling module 6 are identical, and both adopt AD4680 type sampling chips.
The model adopted by the DSP module 7 is TMS320C203PZ 80;
the interface module 8 comprises a Lora module (which uses E32-433T20DC from hundred million corporation) and an RS232 serial module connected in series with each other;
as shown in fig. 2, the invention also provides a working method of the train speed and direction measuring device based on the train sound, which comprises the following steps:
(1) the interface module receives a working instruction from a user and starts the DSP module to start working;
(2) the DSP module closes the second AD sampling module, sets a counter s to be 1, and starts a timer T1 and a timer T2 to start working;
(3) the DSP module controls the first AD sampling module to perform single sampling (wherein the sampling rate is F1-8 KHz, and the single sampling time is Int 1-10 ms) to obtain a plurality of voltage values, and calculates the maximum value q among all the voltage valuesmaxAnd minimum value qminAnd the sum of all voltage values Qsum；
Specifically, in the present invention, since the sampling rate of the first AD sampling module is F1 ═ 8KHz and the single sampling time is Int1 ═ 10ms, F1 × Int1, that is, 80 voltage data are obtained by a single sampling.
(4) The DSP module judges whether q existsmax<a is true, and q ismin<b is true, and Qsum<c is true; if yes, entering the step (5), otherwise, returning to the step (3); wherein a is a first threshold, b is a second threshold, and c is a third threshold;
specifically, the value range of the first threshold a is equal to 1/10 times to 1/5 times, preferably 1/8 times, of the sampling upper limit value of the first AD sampling module; the value range of the second threshold b is equal to 1/20 times to 1/10 times, preferably 1/8 times of the sampling upper limit value of the first AD sampling module; the value range of the third threshold c is equal to 1/12 × F1 × Int1 times to 1/8 × F1 × Int1 times of the sampling upper limit value of the first AD sampling module, and preferably equal to 1/10 × F1 × Int1 times;
the advantage of above-mentioned step (1) to step (4) lies in, it judges through the maximum value and the minimum value of a plurality of voltage values that carry out single sampling to DSP module control first AD sampling module with less sampling rate, short time to prevent pulse class interference, such as car whistle, the cry of birdie, and the like, this kind of interference can make a plurality of voltage value change range great, but voltage sum is less, simultaneously through judging the sum of a plurality of voltage values, find the moment that environmental sound changes relatively more steadily, and as the inception moment of drawing background noise. Compared with the method that the DSP module controls the first AD sampling module to directly calculate and judge whether the voltage values are noise or not by sampling for a single time at a large sampling rate for a long time, the method has the advantages of small calculation amount and higher efficiency, and particularly for the road sections with frequent incoming vehicles, the calculation amount can be greatly reduced.
(5) The DSP module sets a counter i to be 1;
(6) the DSP module controls the first AD sampling module and the second AD sampling module to respectively carry out single sampling (the sampling rate is set to be F2 ═ 20k, and the single sampling time is set to be Int2 ═ 50ms) so as to respectively obtain the ith sampling result XiAnd Yi(wherein XiAnd YiEach comprising 1000 voltage values);
(7) the DSP module judges whether the timer T1 is overtime, if yes, i is set to i +1, and the step (8) is carried out, otherwise, the judging process of the step (7) is continued;
specifically, the timeout period of the timer T1 set in this step is 500 ms.
(8) The DSP module judges whether i is larger than a preset sampling frequency threshold FRA, if so, the step (9) is carried out, otherwise, the step (6) is carried out;
specifically, the sampling number threshold FRA is a natural number, and FRA ∈ [3, 10 ].
(9) The DSP module is used for sampling all the sampling results XiAnd YiCalculating corresponding average energy values D1 and D2 respectively;
specifically, the following formula is adopted in this step:
the advantage of the foregoing steps (5) to (9) is that the DSP module controls the first AD sampling module and the second AD sampling module to respectively perform multiple sampling to obtain two sets of voltage values, and further calculate the average energy values D1 and D2 in the set, which are used as the background of the environmental noise, so as to improve the calculation accuracy of the train speed when the train approaches.
(10) The DSP module controls the first AD sampling module and the second AD sampling module to respectively carry out single sampling (the sampling rate is set to be F2 ═ 20k, and the single sampling time is set to be Int2 ═ 50ms) so as to respectively obtain the s-th sampling result AsAnd Bs(wherein A issAnd BsEach comprising 1000 voltage values);
(11) the DSP module respectively calculates sampling results AsAnd BsSum of all voltage values of (1) Sum1sAnd Sum2sAnd judging whether Sum1 existssAnd Sum2sIf the train speed and direction measuring signals are all larger than the preset threshold Th, the train approaches the train speed and direction measuring device based on the train sound and the step (12) is carried out, otherwise, no train approaches the train speed and direction measuring device based on the train sound and the step (17) is carried out;
specifically, the value range of the preset threshold Th in this step is equal to 1/6 × F2 × Int2 times to 1/4 × F2 × Int2 times of the sampling upper limit value of the first AD sampling module, and is preferably 1/5 × F2 × Int2 times;
(12) the DSP module samples the result A of the s timesAnd BsRespectively carrying out discrete Fourier transform to respectively obtain transform results CsAnd DsAnd separately applying spectral subtraction to the transformation result CsAnd DsAre processed to obtain results E respectivelysAnd Fs；
Specifically, Es＝|Cs|-a1*D1，Fs＝|Ds|-a1*D2；
Wherein a1 represents a weight value, and the value range thereof is 0.8 to 1.5, preferably 1.2.
(13) The DSP module respectively processes the results E obtained in the step (12)sAnd FsPerforming discrete Fourier transform to obtain transform results PsAnd QsComputing a transformation result PsAnd QsAnd obtaining the argument h corresponding to the minimum value of the correlation functions；
The step (12) and the step (13) have the advantages that the noise reduction processing is respectively carried out on the signals received by the two paths of sound sensing modules through the spectral subtraction method, and then the time delay between the two paths of signals of the cross-correlation function is utilized to improve the accuracy of time delay calculation and further improve the accuracy of speed calculation.
(14) The DSP module obtains the independent variable h according to the step (13)sAcquiring an included angle INC between a connection line between the centers of mass of a microphone of the first sound sensing module and the mass of a microphone of the second sound sensing module and a railsAnd determining the included angle INCsIf the train direction is less than 90 degrees, sending information that the train direction is from the first sound sensing module to the second sound sensing module to the interface module if the train direction is less than 90 degrees, then entering the step (15), otherwise sending information that the train direction is from the second sound sensing module to the first sound sensing module to the interface module, and entering the step (15);
in particular, INCs＝arccos(c*hs/(F2*d))
Wherein c represents the speed of sound and d represents the distance between the center of mass of the microphone in the first sound sensing module and the center of mass of the microphone in the second sound sensing module;
the advantage of the above step (14) is that it is performed by applying the argument h obtained in step (13)s comeAcquiring an included angle INC between a connection line between the centers of mass of a microphone of the first sound sensing module and the mass of a microphone of the second sound sensing module and a railsAnd the direction of the train is judged by judging the relation between the included angle and 90 degrees, so that the cost is greatly reduced, the power consumption of the system is reduced, and the portability of the system is enhanced compared with the method of jointly measuring the direction by using a plurality of sensors.
(15) The DSP module obtains the included angle INC according to the step (14)sObtaining the distance D between the perpendicular projection of the centers of the mass center of the microphone of the first sound sensing module and the mass center of the microphone of the second sound sensing module on the rail and the train obtained in the s-th timesAnd judging whether s is larger than 1, if so, entering the step (16), otherwise, returning to the step (10);
specifically, the distance Ds＝L/tanINCsAnd L represents the distance between the first sound sensing module and the second sound sensing module and the rail on the side closest to the first sound sensing module and the second sound sensing module.
(16) The DSP module obtains the distance D according to the s timesAnd the distance D obtained at the s-1 st times-1Calculating the train speed, sending the calculated train speed to an interface module, and setting s to be s + 1;
specifically, the train speed is (D)s-Ds-1) and/T, which is expressed in meters/second, wherein T represents the timeout duration of the timer T2, which takes 500 ms.
The above steps (14) to (16) are advantageous in that they pass through the s-th obtained distance DsAnd the distance D obtained at the s-1 st times-1And obtaining the distance D twicesAnd Ds-1And the train speed is calculated according to the geometric relation between the system installation position and the train position, the speed updating real-time performance is high, the calculated amount is small, and the delay is low.
(17) The interface module judges whether a sleep instruction from a user is received, if so, the process is ended, otherwise, the step (18) is carried out;
(18) the interface module judges whether an environmental noise updating instruction from a user is received, if so, the user finds that a new noise source exists at the position where the system of the invention is located, and returns to the step (2), otherwise, the user does not find that the new noise source exists at the position where the system of the invention is located, and returns to the step (10);
the advantage of the above step (18) is that it updates the background of the environmental noise by determining whether the interface module receives the environmental noise update instruction from the user, thereby enhancing the adaptability of the system to the area with large environmental change.
It will be understood by those skilled in the art that the foregoing is only a preferred embodiment of the present invention, and is not intended to limit the invention, and that any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the scope of the present invention.
Claims (9)
1. A train speed and direction measuring device based on train sound comprises a first sound sensing module, a second sound sensing module, a first signal adjusting module, a second signal adjusting module, a first AD sampling module, a second AD sampling module, a DSP module and an interface module,
the first sound sensing module, the first signal adjusting module, the first AD sampling module, the DSP module and the interface module are sequentially connected in series;
the second sound sensing module, the second signal conditioning module, the second AD sampling module, the DSP module and the interface module are sequentially connected in series.
2. The train sound-based train speed and direction measuring device according to claim 1, wherein in operation, the first sound sensing module and the second sound sensing module are both disposed parallel to a side rail, and the first sound sensing module and the second sound sensing module are both perpendicular to the side rail, the distance d between the first sound sensing module and the second sound sensing module is 10 cm to 30 cm, preferably 20 cm, and the distance L between the first sound sensing module and the second sound sensing module is 10m to 50m, preferably 30 m.
3. The train sound-based train speed and direction measuring device according to claim 1 or 2,
the first sound sensing module and the second sound sensing module are completely the same and both adopt KY-037 type sound sensors;
the first signal conditioning module and the second signal conditioning module are completely the same and respectively comprise a preceding-stage amplification circuit, a low-pass filter circuit and a subsequent-stage amplification circuit which are sequentially connected in series. The front-stage amplification circuit and the rear-stage amplification circuit both adopt ADA4625-2 type operational amplifiers; the low-pass filter circuit is a 3-order Butterworth low-pass filter consisting of an ADA4625-2 type operational amplifier, and the 3dB cut-off frequency is 10 kHz;
the first AD sampling module and the second AD sampling module are completely the same and adopt AD4680 type sampling chips;
the model of the DSP module is TMS320C203PZ 80;
the interface module comprises a Lora module and an RS232 serial port module which are connected with each other in series.
4. A method for operating a train speed and direction measuring device based on train sound according to any one of claims 1 to 3, comprising the steps of:
(1) the interface module receives a working instruction from a user and starts the DSP module to start working;
(2) the DSP module closes the second AD sampling module, sets a counter s to be 1, and starts a timer T1 and a timer T2 to start working;
(3) the DSP module controls the first AD sampling module to perform single sampling so as to obtain a plurality of voltage values, and calculates the maximum value q of all the voltage valuesmaxAnd minimum value qminAnd the sum of all voltage values Qsum；
(4) The DSP module judges whether q existsmax<a is true, and q ismin<b is true, and Qsum<c is true; such asIf yes, entering the step (5), otherwise, returning to the step (3); wherein a is a first threshold, b is a second threshold, and c is a third threshold;
(5) the DSP module sets a counter i to be 1;
(6) the DSP module controls the first AD sampling module and the second AD sampling module to respectively carry out single sampling so as to respectively obtain the ith sampling result XiAnd Yi；
(7) The DSP module judges whether the timer T1 is overtime, if yes, i is set to i +1, and the step (8) is carried out, otherwise, the judging process of the step (7) is continued;
(8) the DSP module judges whether i is larger than a preset sampling frequency threshold FRA, if so, the step (9) is carried out, otherwise, the step (6) is carried out; wherein FRA ∈ [3, 10 ].
(9) The DSP module is used for sampling all the sampling results XiAnd YiCalculating corresponding average energy values D1 and D2 respectively;
(10) the DSP module controls the first AD sampling module and the second AD sampling module to respectively carry out single sampling so as to respectively obtain an s-th sampling result AsAnd Bs；
(11) The DSP module respectively calculates sampling results AsAnd BsSum of all voltage values of (1) Sum1sAnd Sum2sAnd judging whether Sum1 existssAnd Sum2sIf the train speed and direction measuring signals are all larger than the preset threshold Th, the train approaches the train speed and direction measuring device based on the train sound and the step (12) is carried out, otherwise, no train approaches the train speed and direction measuring device based on the train sound and the step (17) is carried out;
(12) the DSP module samples the result A of the s timesAnd BsRespectively carrying out discrete Fourier transform to respectively obtain transform results CsAnd DsAnd separately applying spectral subtraction to the transformation result CsAnd DsAre processed to obtain results E respectivelysAnd Fs；
(13) The DSP module respectively processes the results E obtained in the step (12)sAnd FsPerforming discrete Fourier transform to obtain transform results PsAnd QsComputing a transformation result PsAnd QsAnd obtaining the argument h corresponding to the minimum value of the correlation functions；
(14) The DSP module obtains the independent variable h according to the step (13)sAcquiring an included angle INC between a connection line between the centers of mass of a microphone of the first sound sensing module and the mass of a microphone of the second sound sensing module and a railsAnd determining the included angle INCsIf the train direction is less than 90 degrees, sending information that the train direction is from the first sound sensing module to the second sound sensing module to the interface module if the train direction is less than 90 degrees, then entering the step (15), otherwise sending information that the train direction is from the second sound sensing module to the first sound sensing module to the interface module, and entering the step (15);
(15) the DSP module obtains the included angle INC according to the step (14)sObtaining the distance D between the perpendicular projection of the centers of the mass center of the microphone of the first sound sensing module and the mass center of the microphone of the second sound sensing module on the rail and the train obtained in the s-th timesAnd judging whether s is larger than 1, if so, entering the step (16), otherwise, returning to the step (10);
(16) the DSP module obtains the distance D according to the s timesAnd the distance D obtained at the s-1 st times-1Calculating the train speed, sending the calculated train speed to an interface module, and setting s to be s + 1;
(17) the interface module judges whether a sleep instruction from a user is received, if so, the process is ended, otherwise, the step (18) is carried out;
(18) and (3) judging whether an environmental noise updating instruction from a user is received or not by the interface module, if so, indicating that a new noise source exists at the position where the system is found by the user, returning to the step (2), otherwise, indicating that the new noise source does not exist at the position where the system is not found by the user, and returning to the step (10).
5. The operating method of the train speed and direction measuring device based on train sound according to claim 4,
in the step (3), the sampling rate is F1-8 KHz, and the single sampling time is Int 1-10 ms;
the value range of the first threshold a is equal to 1/10 times to 1/5 times of the sampling upper limit value of the first AD sampling module;
the value range of the second threshold b is equal to 1/20 times to 1/10 times of the sampling upper limit value of the first AD sampling module;
the third threshold c ranges from 1/12 × F1 × Int1 to 1/8 × F1 × Int1 times the sampling upper limit value of the first AD sampling module.
6. The operating method of the train speed and direction measuring device based on train sound according to claim 5,
the sampling rate in the step (6) and the step (10) is F2 ═ 20k, and the single sampling time is Int2 ═ 50 ms;
the timeout period of the timer T1 in step (7) is 500 ms.
7. The operating method of the train speed and direction measuring device based on train sound according to claim 6,
the step (9) adopts the following formula:
in the step (11), the range of the preset threshold Th is equal to 1/6 × F2 × Int2 times to 1/4 × F2 × Int2 times of the sampling upper limit value of the first AD sampling module.
8. The operating method of the train speed and direction measuring device based on train sound according to claim 7,
result E in step (12)s＝|Cs|-a1*D1，Fs＝|DsL-a 1 × D2, wherein a1 represents a weight value, and the value ranges from 0.8 to 1.5, preferably 1.2;
in step (14), the included angle INCsINCs＝arccos(c*hs/(F2*d))
Where c represents the speed of sound and d represents the distance between the center of mass of the microphone in the first sound sensing module and the center of mass of the microphone in the second sound sensing module.
9. The operating method of a train speed and direction measuring device based on train sound according to claim 8,
distance Ds＝L/tanINCsWherein L represents the distance from the first sound sensing module and the second sound sensing module to the rail on the side closest to the first sound sensing module and the second sound sensing module;
train speed ═ (D)s-Ds-1) and/T, which is expressed in meters/second, wherein T represents the timeout duration of the timer T2, which takes 500 ms.
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