CN107490617B - Weak magnetic nondestructive detection sensor for defects of coal bed gas pipeline and use method - Google Patents
Weak magnetic nondestructive detection sensor for defects of coal bed gas pipeline and use method Download PDFInfo
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Abstract
The invention belongs to the field of magnetic flux leakage nondestructive detection, and provides a weak magnetic nondestructive detection sensor for coal bed gas pipeline defects and a using method thereof. The sensor has a simple structure, the data processing adopts a K nearest neighbor classification algorithm to fuse multi-parameter information, and the sensor has the characteristics of higher resolution, higher accuracy and higher reliability and can be widely applied to the field of pipeline detection.
Description
Technical Field
The invention relates to an intelligent sensor for nondestructive testing of defects of a coal bed gas pipeline, in particular to a weak magnetic nondestructive testing sensor for defects of the coal bed gas pipeline and a using method thereof, and belongs to the field of magnetic leakage nondestructive testing.
Background
Coal bed gas is a clean and high-quality energy and chemical raw material which rises internationally in nearly one and two decades, and is an effective way for relieving the gap of natural gas supply and demand. In order to ensure that the energy of the coal bed gas can be fully utilized, advanced and complete technical equipment is adopted to explore and develop the coal bed gas in a reservoir, and effective measures are adopted to timely solve the problems in pipeline transportation. At present, the methods for detecting pipelines at home and abroad comprise a transmission detection method, a stress strain measurement method, a sound wave/ultrasonic wave reflection method, an ultrasonic guided wave detection method, an optical fiber detection method, a magnetic flux leakage detection method and the like. The method based on magnetic leakage detection develops most rapidly, mainly detects the defects of a ferromagnetic sample by detecting the change of a magnetic leakage field in the ferromagnetic sample, but because the ferromagnetic sample needs to be magnetized, the natural magnetic information reflected by the surface of a part is covered, and the method is not suitable for some high-precision equipment which does not allow magnetization, a new nondestructive detection sensor for the coal bed gas pipeline is urgently needed.
Disclosure of Invention
The invention overcomes the defects of the prior art, and solves the technical problems that: the weak magnetic nondestructive detection sensor for the defects of the coal bed gas pipeline is used for sensing and detecting the magnetic field of the defects of the pipeline on the basis of not magnetizing the pipeline by utilizing a novel sensor based on a tunnel magneto-resistance effect.
In order to solve the technical problems, the invention adopts the technical scheme that: the weak magnetic nondestructive detection sensor for the defects of the coal bed gas pipeline comprises a frame body, wherein 2 walking wheels are respectively arranged on two sides of the frame body, the walking wheels rotate along the inner wall of the coal bed gas pipeline under the drive of a motor to enable the frame body to walk along the inner wall of the coal bed gas pipeline, a first sensor probe array and a second sensor probe array which are identical in structure are respectively fixedly arranged at the front end and the rear end of the frame body, a correlation type infrared head sensor which is positioned on two sides of one walking wheel is fixedly arranged on the frame body, a plurality of light blocking blocks used for blocking light paths of the correlation type infrared head sensor are uniformly arranged on the walking wheels along the circumferential direction, the distance D between the first sensor probe array and the second sensor probe array is L/N, L is the distance for the walking wheels to walk for one circle of the frame body, and N is the number of; the first sensor probe array and the second sensor probe array both comprise a plurality of magnetic field sensor probes symmetrically arranged along the circumferential direction, and when the frame body travels along the inner wall of the coal bed gas pipeline, the circumferences of the magnetic field sensor probes on the first sensor probe array and the second sensor probe array are concentric with the circumference of the cross section of the coal bed gas pipeline; still be provided with signal acquisition circuit on the support body, signal acquisition circuit is including gathering amplifier module, real-time clock module, industrial computer and storage module, the output of magnetic field sensor probe is connected with the industrial computer through gathering amplifier module, correlation formula infrared head sensor's output with the industrial computer is connected, gather amplifier module and be used for enlargiing the back with the signal that magnetic field sensor probe gathered, send for the industrial computer, real-time clock module is used for providing clock signal for the industrial computer, correlation formula infrared head sensor is used for giving the industrial computer outputs periodic trigger signal, the industrial computer is used for the basis the trigger signal of correlation formula infrared head sensor output carries out the data of magnetic field sensor probe and clock signal's collection to with data storage to storage module.
The magnetic field sensor probe is TMR2301 triaxial linear transducer, first sensor probe array and second sensor probe array all include 12 TMR2301 triaxial linear transducer, be provided with 12 blocks of being in the light on the walking wheel.
The weak magnetic nondestructive detection sensor for the defects of the coal bed gas pipeline further comprises a wireless transmitting device arranged on the frame body and a receiver arranged on the ground, the industrial personal computer is provided with safe time, when no low-level signal is transmitted within the safe time, the industrial personal computer outputs a control signal to stop the motor from running, a distress signal is transmitted to the receiver through the wireless transmitting device, and the receiver gives an alarm prompt after receiving the distress signal.
The weak magnetic nondestructive detection sensor for the defects of the coal bed gas pipeline further comprises a pipe brush arranged in front of the frame body, and the pipe brush is used for cleaning the inner wall of the coal bed gas pipeline.
The invention also provides a using method of the weak magnetic nondestructive testing sensor for the defects of the coal bed gas pipeline, which comprises the following steps:
(S1) driving the frame body to walk in the coal bed gas pipeline through a motor, and collecting magnetic field data in the coal bed gas pipeline through two sensor probe arrays arranged at two ends of the frame body;
(S2) N light blocking devices are symmetrically arranged on the travelling wheels, N low-level pulse signals are sent out when the travelling wheels rotate for one circle, an industrial personal computer is triggered to carry out data acquisition for the first time, and the industrial personal computer stores the magnetic field digital signals, the pulse values and the real-time clock signals into a storage module in an array form after processing;
(S3) data of all the sensor probes in each sensor probe array in all directions under the same pulse signal are superposed to obtain a voltage signal of a tangential component X, Y measured by the first sensor probe array under all the pulse signals, wherein the voltage signal is KU1x(m)、KU1y(m) voltage signal KU of normal component Z1z(m) and the voltage signal of the tangential component X, Y measured by the second sensor probe array is KU2x(m)、KU2y(m), voltage signal KU of normal component Z2z(m); wherein m represents a pulse number;
(S4) fitting the magnetic field data set in the same direction by a least square method to obtain a magnetic field data curve equation KU in three directionsx(l)、KUy(l)，KUz(l) (ii) a l represents a coordinate value of the gas formation pipe in the length direction;
(S5) judging the defects of the gas layer pipeline by a multi-parameter information fusion technology: setting the threshold value of the gradient of the tangential component of the magnetic field intensity to be KT1The threshold value of the gradient of the normal component of the magnetic field intensity is KT2Threshold value of standard deviation of integral singular degree value of tangential component data
Normal component data integral singular degree value standard deviation threshold value sigmaT(z) finding a feature vector
And according to the criterion condition:
(1)Hpzero crossing points;
(2)
(3)
(4)
(5)σ(z)≤σT(z)；
judging 5 characteristic values in the characteristic vector T by adopting a K nearest neighbor classification algorithm, and judging that the pipeline has defects when 4 or all characteristic values in the characteristic vector T meet the criterion condition; wherein HpThe normal component is represented as a function of,
denotes the tangential gradient, KzThe normal gradient is represented by the normal gradient,
and expressing the standard deviation of the integral singular degree value of the tangential component data, and expressing the standard deviation of the integral singular degree value of the normal component data by sigma (z).
The step (S4) specifically includes:
determining magnetic field data KU of the first sensor in three directions under the m-th pulse1x(m)、KU1y(m)、KU1z(m) and magnetic field data KU of the second sensor in three directions at the m +1 th pulse2x(m+1)、KU2y(m+1)、KU2zAverage value KU of (m +1)x(m)、KUy(m)、KUz(m) wherein, in the above formula,
fitting the average value of the magnetic field data in three directions by a least square method to obtain a magnetic field data curve equation KU in three directionsx(l)、KUy(l)，KUz(l)。
Said normal component HpTangential gradient
Normal gradient KzIntegral singular degree value standard deviation of tangential component data
And the calculation formulas of the standard deviation sigma (z) of the integral singular degree value of the normal component data are respectively as follows:
Hp＝KUz；
wherein, Δ Hp(x) Representing the difference value of two coordinate values in the direction of the tangential component x axis; Δ Hp(y) the difference between two coordinate values in the y-axis direction of the tangential component, Δ XmRepresenting the difference in horizontal distance, Δ H, between two coordinatesp(z) representing the difference between the two coordinate values of the normal component in the z-axis direction; n represents the number of sampling points, Hp(x)iValue, H, representing the ith sample point in the x-axis direction of the tangential componentp(y)iThe value of the ith sample point in the y-axis direction of the tangential component is represented,
averaging the variance of the sum of the squares of the values in the x-direction and the y-direction for n points on the tangential component, Hp(z)iThe value representing the ith sample point in the z-axis direction of the normal component,
indicating the normal directionComponent n sample points.
Compared with the prior art, the invention has the following beneficial effects:
1. the invention only utilizes the geomagnetic field to detect the leakage magnetic field formed at the defect position of the ferromagnetic sample so as to find the defect, and the pipeline is detected by the front sensor probe array and the rear sensor probe array, thus the invention has simple structure, convenient installation and accurate measurement.
2. The method adopts a least square method to fit the measured data, can eliminate the interference caused by partial clutter, adopts a multi-parameter information fusion method for data processing, namely, fuses multi-parameter information through a K nearest neighbor classification algorithm, has the characteristics of higher resolution, higher accuracy and higher reliability, makes up the defects of missing detection, erroneous judgment and the like of a single criterion, and achieves the aim of accurately judging the defects.
3. The low-frequency transmitting module used by the sensor has the great advantages of low cost, convenience in transmission and high transmission efficiency, and when the sensor breaks down, the position of the device can be accurately judged.
Drawings
FIG. 1 is a front view of a weak magnetic nondestructive testing sensor for detecting defects of a coal bed methane pipeline according to the present invention;
FIG. 2 is a top view of FIG. 1;
FIG. 3 is a right side view of FIG. 1;
fig. 4 is a schematic structural diagram of a signal acquisition circuit according to the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below, and it is obvious that the described embodiments are some embodiments of the present invention, but not all embodiments; all other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
As shown in fig. 1-2, the invention provides a weak magnetic nondestructive detection sensor for detecting defects of a coal bed gas pipeline, which comprises a frame body 1, wherein two sides of the frame body 1 are respectively provided with 2 traveling wheels 2, the traveling wheels 2 are driven by a motor 3 to rotate along the inner wall of the coal bed gas pipeline 4, so that the frame body 1 travels forwards along the inner wall of the coal bed gas pipeline 4, the front end and the rear end of the frame body 1 are respectively and fixedly provided with a first sensor probe array 5 and a second sensor probe array 6 which have the same structure, wherein the frame body 1 is fixedly provided with a correlation infrared head sensor 7 which is positioned at two sides of one of the traveling wheels 2, the traveling wheels are uniformly provided with 12 shafts 8 along the circumferential direction, the shafts 8 can be used for blocking the light path of the correlation infrared head sensor 7, and the distance D between the first sensor probe array 5 and the second sensor probe array 6 is L/12, wherein L is the advancing distance of the frame body when the walking wheels walk for one circle;
as shown in fig. 3, which is a schematic structural diagram of a sensor probe array, the sensor probe array includes 12 magnetic field sensor probes 9 symmetrically arranged along a circumferential direction, and the 12 magnetic field sensor probes can detect magnetic fields at 12 positions of a coal bed methane pipeline along the circumferential direction. When the frame body 1 walks along the inner wall 4 of the coal bed gas pipeline, the circumference where the 12 magnetic field sensor probes are located is concentric with the circumference of the cross section of the coal bed gas pipeline.
In addition, as shown in fig. 4, the frame body 1 is further provided with a signal acquisition circuit, the signal acquisition circuit comprises an acquisition amplification module, a real-time clock module, an industrial personal computer and a storage module, the output end of the magnetic field sensor probe is connected with an industrial personal computer through an acquisition amplification module, the output end of the correlation type infrared head sensor is connected with the industrial personal computer, the acquisition amplification module is used for amplifying the signals acquired by the sensor probe and then sending the amplified signals to the industrial personal computer, the real-time clock module is used for providing clock signals for an industrial personal computer, the correlation type infrared head sensor is used for outputting periodic trigger signals for the industrial personal computer, the industrial personal computer is used for acquiring data and clock signals of the magnetic field sensor probe according to the trigger signal output by the correlation type infrared head sensor and storing the acquired data to the storage module. In addition, the signal acquisition circuit can further comprise a power supply module for supplying power to the circuit.
The light blocking blocks can be uniformly arranged on the travelling wheels according to the requirement, and the light blocking device is not limited to blocking light by using shafts arranged on the travelling wheels to form a trigger signal of the correlation infrared head sensor.
Further, the magnetic field sensor probe is a TMR2301 triaxial linear sensor, and the first sensor probe array and the second sensor probe array each include 12 TMR2301 triaxial linear sensors. The TMR2301 triaxial linear sensor adopts three unique Wheatstone full-bridge structural designs, and each Wheatstone full-bridge provides a differential voltage signal Vin-、Vin+The output has the characteristics of good temperature stability, wide voltage working range and low power consumption, and can realize the detection of weak magnetic fields at the defects; in addition, the main chip of the acquisition amplification module can be LM358, each LM358 can be responsible for the signal acquisition amplification part of two TMR2301 linear sensors, therefore, the acquisition amplification module comprises a plurality of LM358 main chips, the main chips have the advantages of internal frequency compensation, high direct-current voltage gain, wide power supply voltage range, high precision and low power consumption, and the amplified signal KU of each TMR2301 linear sensor can be amplifiedx1、KUy1、KUz1Transmitting the data to an industrial personal computer in real time; the real-time clock module main chip is DS1302, can calculate the second, minute, hour, day, week, month and year before 2100 years, also has the leap year adjusting capability, can read the time through the serial I/O port, and occupies less I/O ports; the power supply module uses a 12V storage battery for power supply, and stable direct-current voltage of +/-5V and +/-3.3V is generated by the DC-DC conversion plate to supply power to each module. The storage module can be a solid state disk WDS120G1G0A120GSSD, has the advantages of high access speed, magnetic field interference resistance, high performance, low power consumption, stability, durability, light weight, shock resistance, safety and low power consumption, acquires magnetic leakage signals once every 3ms, records 80 bytes of data (including three-axis signals, clock signals and pulse values of 12 probes) every time, has the capacity of acquiring data of 1h (1h/3ms) 80 data (26 MByte), and can be used for acquiring 2363h by two sensor probe arrays; the industrial control computer is the core unit of the sensor and is mainly responsible for collecting the magnetic field data digital quantity output by the amplification module and real-time clock moduleAnd clock signals given by the blocks and pulse signals sent by the correlation type infrared head sensor are processed and then stored in the hard disk in an array mode. In addition, the industrial personal computer can also control the motor to operate so as to drive the sensor frame body to move forwards. The pulse value refers to a serial number corresponding to a pulse sent by the correlation infrared head sensor.
Further, as shown in fig. 3, the weak magnetic nondestructive detection sensor for coal bed methane pipeline defects in the embodiment of the present invention further includes a wireless transmitting device disposed on the frame body and a receiver disposed on the ground, the industrial personal computer is provided with a safety time, when no low level signal is transmitted within the safety time, the industrial personal computer outputs a control signal to stop the motor from running, and transmits a distress signal to the receiver through the wireless transmitting device, and the receiver performs an alarm prompt after receiving the distress signal. The wireless transmitting device can be a low-frequency transmitting module, the receiver comprises a low-frequency receiving module, and when the low-frequency transmitting module transmits an ultra-low-frequency signal (20-30Hz), the ground low-frequency receiving module can give out an acousto-optic indication to determine the position of the device.
After the pipeline detection work is finished, data in the storage module needs to be processed to obtain the defect condition of the coal bed gas pipeline, in the embodiment of the invention, the data in the storage module can be transmitted to an upper computer, and the upper computer processes and calculates the data, the embodiment of the invention also provides a using method of the weak magnetic nondestructive detection sensor for the defects of the coal bed gas pipeline, which comprises the following steps:
(S1) driving the frame body to walk in the coal bed gas pipeline through a motor, and collecting magnetic field data in the coal bed gas pipeline through two sensor probe arrays arranged at two ends of the frame body;
(S2) N light blocking devices are symmetrically arranged on the travelling wheels, N low-level pulse signals are sent out when the travelling wheels rotate for one circle, an industrial personal computer is triggered to carry out data acquisition for the first time, and the industrial personal computer stores the magnetic field digital signals, the pulse values and the real-time clock signals into a storage module in an array form after processing; the pulse value refers to a serial number corresponding to a pulse transmitted by the correlation infrared head sensor.
(S3) transmitting each signalData of each sensor probe in the sensor probe array in each direction under the same pulse signal are superposed to obtain a voltage signal of a tangential component X, Y measured by the first sensor probe array under each pulse signal, wherein the voltage signal is KU1x(m)、KU1y(m) voltage signal KU of normal component Z1z(m) and the voltage signal of the tangential component X, Y measured by the second sensor probe array is KU2x(m)、KU2y(m), voltage signal KU of normal component Z2z(m); wherein m represents a pulse number;
(S4) fitting the magnetic field data set in the same direction by a least square method to obtain a magnetic field data curve equation KU in three directionsx(l)、KUy(l)，KUz(l) (ii) a l represents a coordinate value of the gas formation pipe in the length direction; the least square fitting can eliminate the interference caused by partial clutter.
(S5) judging the defects of the gas layer pipeline by a multi-parameter information fusion technology: setting the threshold value of the gradient of the tangential component of the magnetic field intensity to be KT1The threshold value of the gradient of the normal component of the magnetic field intensity is KT2Threshold value of standard deviation of integral singular degree value of tangential component data
Normal component data integral singular degree value standard deviation threshold value sigmaT(z) finding a feature vector
And according to the criterion condition:
(1)Hpzero crossing points;
(2)
(3)
(4)
(5)σ(z)≤σT(z)；
judging 5 characteristic values in the characteristic vector T by adopting a K nearest neighbor classification algorithm, and judging that the pipeline has defects when 4 or all characteristic values in the characteristic vector T meet the criterion condition; wherein HpThe normal component is represented as a function of,
denotes the tangential gradient, KzThe normal gradient is represented by the normal gradient,
and expressing the standard deviation of the integral singular degree value of the tangential component data, and expressing the standard deviation of the integral singular degree value of the normal component data by sigma (z).
The K-nearest neighbor classification algorithm means that if most of K most similar samples (i.e., nearest neighbors in the feature space) in the feature space of a sample belong to a certain class, the sample also belongs to the class. The invention makes up the normal vector H by the methodp(y) zero-crossing or tangent vector Hp(x) The defect judgment method has the defects of missing detection, erroneous judgment and the like of single criteria such as the maximum value and the like, and achieves the aim of accurately judging the defect.
Because the walking wheel that corresponds with correlation formula infrared head sensor goes up the symmetry and is provided with 12 blocks that are in the light, then walk the round in every walking equivalent to the walking wheel, the industrial computer gathers 12 times data, because the distance between first sensor probe array 4 and the second sensor probe array 5 satisfies D equals L/12, L is the walking wheel and walks the round in every walking, the distance that the support body gos forward, then be equivalent to when the mth pulse takes place the position that first sensor probe array was located and when the mth +1 pulse was sent the position that second sensor probe array was located the same, KU promptly1x(m)、KU1y(m)、KU1z(m) and KU2x(m+1)、KU2y(m+1)、KU2zThe (m +1) corresponds to magnetic field data at the same position, and therefore, the step (S4) may further specifically include: determining three directions of the first sensor at the m-th pulseMagnetic field data KU1x(m)、KU1y(m)、KU1z(m) and magnetic field data KU of the second sensor in three directions at the m +1 th pulse2x(m+1)、KU2y(m+1)、KU2zAverage value KU of (m +1)x(m)、KUy(m)、KUz(m) wherein:
then, fitting the average value of the magnetic field data in the three directions by a least square method to obtain a magnetic field data curve equation KU in the three directionsx(l)、KUy(l)，KUz(l) In that respect The measured values of the two sensor probe arrays are averaged and then subjected to least square fitting, so that interference caused by partial clutter can be further eliminated.
Further, the normal component HpTangential gradient
Normal gradient KzIntegral singular degree value standard deviation of tangential component data
And the calculation formulas of the standard deviation sigma (z) of the integral singular degree value of the normal component data are respectively as follows:
Hp＝KUz； (4)
wherein, Δ Hp(x) Representing the difference value of two coordinate values in the tangential component X-axis direction; Δ Hp(y) the difference between two coordinate values in the y-axis direction of the tangential component, Δ XmRepresenting the difference in horizontal distance, Δ H, between two coordinatesp(z) representing the difference between the two coordinate values of the normal component in the z-axis direction; n represents the number of sampling points, Hp(x)iValue, H, representing the ith sample point in the X-axis direction of the tangential componentp(y)iThe value of the ith sample point in the y-axis direction of the tangential component is represented,
averaging the variance of the sum of the squares of the values in the X-direction and the y-direction for n points on the tangential component, Hp(z)iThe value representing the ith sample point in the z-axis direction of the normal component,
representing the average of the n sample points of the normal component.
The parameters of the sensor of the invention are as follows:
sensitivity: 1mV/V/Oe
Hysteresis: 0.01Oe
Operating voltage and current: VCC is more than or equal to-5V and less than or equal to 7V, and I is less than or equal to 20mA
Drifting: less than or equal to 3nT/h
Magnetic field intensity range: 500Oe
Working temperature: -40 ℃ to 125 DEG C
The communication protocol is as follows: a UART.
Finally, it should be noted that: the above embodiments are only used to illustrate the technical solution of the present invention, and not to limit the same; while the invention has been described in detail and with reference to the foregoing embodiments, it will be understood by those skilled in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some or all of the technical features may be equivalently replaced; and the modifications or the substitutions do not make the essence of the corresponding technical solutions depart from the scope of the technical solutions of the embodiments of the present invention.
Claims (7)
1. The weak magnetic nondestructive detection sensor for the defects of the coal bed gas pipeline is characterized by comprising a frame body, two sides of the frame body are respectively provided with 2 travelling wheels, the travelling wheels are driven by a motor to rotate along the inner wall of the coal bed gas pipeline, so that the frame body travels along the inner wall of the coal bed gas pipeline, the front end and the rear end of the frame body are respectively and fixedly provided with a first sensor probe array and a second sensor probe array which have the same structure, the frame body is fixedly provided with a correlation type infrared head sensor positioned on two sides of one of the travelling wheels, a plurality of light blocking blocks used for blocking the light path of the correlation type infrared head sensor are uniformly arranged on the travelling wheel along the circumferential direction, and the distance D between the first sensor probe array and the second sensor probe array is equal to L/N, wherein L is the advancing distance of the travelling wheel for a circle of frame body, and N is the number of the light blocking blocks;
the first sensor probe array and the second sensor probe array both comprise a plurality of magnetic field sensor probes symmetrically arranged along the circumferential direction, and when the frame body travels along the inner wall of the coal bed gas pipeline, the circumferences of the magnetic field sensor probes on the first sensor probe array and the second sensor probe array are concentric with the circumference of the cross section of the coal bed gas pipeline;
still be provided with signal acquisition circuit on the support body, signal acquisition circuit is including gathering amplifier module, real-time clock module, industrial computer and storage module, the output of magnetic field sensor probe is connected with the industrial computer through gathering amplifier module, correlation formula infrared head sensor's output with the industrial computer is connected, gather amplifier module and be used for enlargiing the back with the signal that magnetic field sensor probe gathered, send for the industrial computer, real-time clock module is used for providing clock signal for the industrial computer, correlation formula infrared head sensor is used for giving the industrial computer outputs periodic trigger signal, the industrial computer is used for the basis the trigger signal of correlation formula infrared head sensor output carries out the data of magnetic field sensor probe and clock signal's collection to with data storage to storage module.
2. The weak magnetic nondestructive detection sensor for defects of coal bed gas pipelines according to claim 1, wherein the magnetic field sensor probe is a TMR2301 three-axis linear sensor, the first sensor probe array and the second sensor probe array each comprise 12 TMR2301 three-axis linear sensors, and the traveling wheel is provided with 12 light blocks.
3. The weak magnetic nondestructive detection sensor for the defects of the coal bed gas pipeline is characterized by further comprising a wireless transmitting device arranged on the frame body and a receiver arranged on the ground, wherein the industrial personal computer is provided with safe time, when no low-level signal is transmitted within the safe time, the industrial personal computer outputs a control signal to stop the motor from running, a distress signal is transmitted to the receiver through the wireless transmitting device, and the receiver gives an alarm prompt after receiving the distress signal.
4. The weak magnetic nondestructive detection sensor for the defects of the coal bed gas pipeline is characterized by further comprising a pipe brush arranged in front of the frame body, wherein the pipe brush is used for cleaning the inner wall of the coal bed gas pipeline.
5. The use method of the weak magnetic nondestructive detection sensor for the defects of the coal bed gas pipeline is characterized by comprising the following steps:
(S1) driving the frame body to walk in the coal bed gas pipeline through a motor, and collecting magnetic field data in the coal bed gas pipeline through two sensor probe arrays arranged at two ends of the frame body;
(S2) N light blocking devices are symmetrically arranged on the travelling wheels, N low-level pulse signals are sent out when the travelling wheels rotate for one circle, an industrial personal computer is triggered to carry out data acquisition for the first time, and the industrial personal computer stores the magnetic field digital signals, the pulse values and the real-time clock signals into a storage module in an array form after processing;
(S3) data of all the sensor probes in each sensor probe array in all directions under the same pulse signal are superposed to obtain a voltage signal of a tangential component X, Y measured by the first sensor probe array under all the pulse signals, wherein the voltage signal is KU1x(m)、KU1y(m) voltage signal KU of normal component Z1z(m) and the voltage signal of the tangential component X, Y measured by the second sensor probe array is KU2x(m)、KU2y(m), voltage signal KU of normal component Z2z(m); wherein m represents a pulse number;
(S4) fitting the magnetic field data set in the same direction by a least square method to obtain a magnetic field data curve equation KU in three directionsx(l)、KUy(l)，KUz(l) (ii) a l represents the coordinate value of the gas layer pipeline along the length direction;
(S5) judging the defects of the gas layer pipeline by a multi-parameter information fusion technology: setting the threshold value of the gradient of the tangential component of the magnetic field intensity to be KT1The threshold value of the gradient of the normal component of the magnetic field intensity is KT2Threshold value of standard deviation of integral singular degree value of tangential component data
Normal component data integral singular degree value standard deviation threshold value sigmaT(z) finding a feature vector
And according to the criterion condition:
(1)Hpzero crossing points;
(2)
(3)
(4)
(5)σ(z)≤σT(z)；
judging 5 characteristic values in the characteristic vector T by adopting a K nearest neighbor classification algorithm, and judging that the pipeline has defects when 4 or all characteristic values in the characteristic vector T meet the criterion condition; wherein HpThe normal component is represented as a function of,
denotes the tangential gradient, KzThe normal gradient is represented by the normal gradient,
and expressing the standard deviation of the integral singular degree value of the tangential component data, and expressing the standard deviation of the integral singular degree value of the normal component data by sigma (z).
6. The use method of the weak magnetic nondestructive testing sensor for the defects of the coal bed gas pipeline is characterized in that the step (S4) specifically comprises the following steps:
determining magnetic field data KU of the first sensor in three directions under the m-th pulse1x(m)、KU1y(m)、KU1z(m) and magnetic field data KU of the second sensor in three directions at the m +1 th pulse2x(m+1)、KU2y(m+1)、KU2zAverage value KU of (m +1)x(m)、KUy(m)、KUz(m) wherein, in the above formula,
fitting the average value of the magnetic field data in three directions by a least square method to obtainMagnetic field data curve equation KU in three directionsx(l)、KUy(l)，KUz(l)。
7. The use method of the weak magnetic nondestructive testing sensor for the defects of the coal bed gas pipeline as claimed in claim 5, wherein the normal component H ispTangential gradient
Normal gradient KzIntegral singular degree value standard deviation of tangential component data
And the calculation formulas of the standard deviation sigma (z) of the integral singular degree value of the normal component data are respectively as follows:
Hp＝KUz；
wherein, Δ Hp(x) Representing the difference value of two coordinate values in the direction of the tangential component x axis; Δ Hp(y) the difference between two coordinate values in the y-axis direction of the tangential component, Δ XmRepresenting the difference in horizontal distance, Δ H, between two coordinatesp(z) representing the difference between the two coordinate values of the normal component in the z-axis direction; n represents the number of sampling points, Hp(x)iValue, H, representing the ith sample point in the x-axis direction of the tangential componentp(y)iRepresenting tangential componentsThe value of the ith sample point in the y-axis direction,
averaging the variance of the sum of the squares of the values in the x-direction and the y-direction for n points on the tangential component, Hp(z)iThe value representing the ith sample point in the z-axis direction of the normal component,
representing the average of the n sample points of the normal component.
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| CN114623954A (en) * | 2020-12-10 | 2022-06-14 | 中国石油天然气集团有限公司 | Internal detection device and equipment for detecting stress of oil and gas pipeline |
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