CN111060587B - Magnetic flux leakage detection probe attitude compensation method and device - Google Patents
Magnetic flux leakage detection probe attitude compensation method and device Download PDFInfo
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Abstract
The invention discloses a method and a device for compensating the attitude of a magnetic flux leakage detection probe, wherein the method comprises the following steps: acquiring the tangential distance of two triaxial magnetic field measurement chips in a normal posture; acquiring a magnetic field value under the current probe inclination condition by using two triaxial magnetic field measurement chips; filtering and differentiating two groups of tangential components in the obtained magnetic field values to obtain differential values of two groups of magnetic field measurement signals; marking the characteristics of the differential values respectively to obtain flat data segments with characteristic differential values as constants; respectively recording the middle points of the flat data segments as defect centers, and recording first and second mileage distances corresponding to the defect centers; calculating the current probe attitude inclination angle according to the first and second mileage distances and the tangential distances of the two measurement chips; and (4) performing compensation calculation on the obtained magnetic field value by using the inclination angle to obtain a defect magnetic flux leakage signal under the correct posture of the probe. The method can complete the measurement of the magnetic leakage signal and the real-time compensation of the magnetic leakage signal in the inclined posture under the condition that the posture of the probe is inclined.
Description
Technical Field
The invention relates to the technical field of nondestructive testing, in particular to a method and a device for compensating the attitude of a magnetic flux leakage testing probe.
Background
For nondestructive testing of oil and gas pipelines and petroleum storage tank bottom plates, magnetic flux leakage testing is one of the most common online testing techniques. The magnetic leakage detection is mainly to detect the distribution and the size of a leakage magnetic field at the defect position of a test piece through saturation magnetization of the test piece, and further solve the defect size information. However, in the actual detection process, the magnetic flux leakage detection probe may generate a flutter phenomenon when passing through a flange, a weld joint and the like, and the flutter may cause the posture of the probe to incline; the problem of probe attitude tilt caused by excessive wear of one side of a mechanical shell of the probe can also occur in the detection process. The signals measured by the inclined probe greatly influence the judgment and quantification of the defects, so the posture problem of the probe is always the key and difficult point of the defect detection technology.
In the prior art, the main method for solving the posture problem of the probe is to enable the probe to be tightly attached to the outer wall by optimizing the mechanical design of the probe and adding spring pieces and other means. However, in the actual detection process, due to irresistible reasons such as abrasion, mechanical deviation and the like, the magnetic flux leakage detection probe may have a posture inclination problem at any time, and due to the existence of chatter, the inclination degree of the probe at each defect position may be inconsistent.
Disclosure of Invention
The present invention is directed to solving, at least to some extent, one of the technical problems in the related art.
Therefore, an object of the present invention is to provide an attitude compensation method for a magnetic flux leakage detection probe, which can perform measurement of a magnetic flux leakage signal and real-time compensation of an inclined attitude magnetic flux leakage signal when an attitude of the probe is inclined.
Another object of the present invention is to provide an attitude compensation device for a magnetic flux leakage detection probe.
In order to achieve the above object, an embodiment of the present invention provides a method for compensating an attitude of a magnetic flux leakage detection probe, including:
s1, acquiring the distance of the two triaxial magnetic field measurement chips in the tangential direction under the normal posture;
s2, respectively acquiring magnetic field values under the current probe inclination condition by using the two triaxial magnetic field measurement chips, wherein the magnetic field values comprise a tangential component and a normal component;
s3, filtering two groups of tangential components in the obtained magnetic field values, and differentiating the two groups of filtered tangential components to obtain differential values of two groups of magnetic field measurement signals;
s4, marking the characteristics of the differential values of the two groups of magnetic field measurement signals respectively to obtain flat data segments with constant characteristic differential values;
s5, recording a first mileage distance and a second mileage distance corresponding to the defect center by respectively recording the middle points of the flat data segments as the defect center;
s6, calculating the inclination angle of the current probe attitude according to the first mileage distance, the second mileage distance and the distance of the two magnetic field measurement chips in the normal attitude in the tangential direction;
and S7, performing compensation calculation on the magnetic field value under the current probe inclination condition by using the inclination angle of the current probe attitude to obtain a defect magnetic flux leakage signal under the correct probe attitude.
According to the magnetic flux leakage detection probe attitude compensation method, two groups of three-dimensional magnetic field values under the current inclination angle can be acquired through the two magnetic field measurement chips, the attitude angle of the current probe can be reversely calculated by combining the measured magnetic field values and the fixed distance between the two magnetic field measurement chips, and the magnetic field measured under the condition that the probe is inclined is compensated into the defect magnetic flux leakage signal measured under the correct attitude by utilizing the attitude angle of the current probe. The method can complete the measurement of the magnetic leakage signal and the real-time compensation of the magnetic leakage signal in the inclined posture under the condition that the posture of the probe is inclined.
In addition, the magnetic flux leakage detection probe attitude compensation method according to the above embodiment of the present invention may further have the following additional technical features:
further, in an embodiment of the present invention, the flat data segment whose characteristic differential value is constant includes:
the maximum value and the minimum value of the differential values of the two groups of magnetic field measurement signals and the differential between the maximum value and the minimum value are flat sections with constant or approximate constant.
Further, in an embodiment of the present invention, the magnetic field values under the current probe tilt condition include:
the first triaxial magnetic field measuring chip measures the tangential component B of the magnetic fieldx1cAnd a normal component Bz1cThe tangential component B of the magnetic field measured by the second triaxial magnetic field measuring chipx2cAnd a normal component Bz2c(ii) a Tangential is the direction along the magnetization, denoted by the subscript x; the normal direction is the direction perpendicular to the surface of the test piece and is denoted by the subscript z.
Further, in an embodiment of the present invention, the formula of the tilt angle for calculating the current probe attitude according to the first mileage distance, the second mileage distance and the distance between the two magnetic field measurement chips in the normal attitude in the tangential direction is as follows:
where θ is the angle of inclination of the current probe attitude, l1Is the first mileage distance,/2Is the second mileage distance.
Further, in an embodiment of the present invention, the S7 further includes:
utilizing the inclination angle theta of the current probe attitude to measure the magnetic field value B under the condition that the current probe is inclinedx1c、Bx2c、Bz1cAnd Bz2cPerforming compensation calculation to obtain a defect flux leakage signal under the correct posture of the probe, wherein the defect flux leakage signal comprises a tangential component Bx1、Bx2And a normal component Bz1、Bz2Defect leakage signal B at said correct attitudex1、Bx2、Bz1、Bz2The inclination angle theta of the current probe posture and the magnetic field value B under the condition of probe inclinationx1c、Bx2c、Bz1cAnd Bz2cThe relationship of (1) is:
in order to achieve the above object, an embodiment of another aspect of the present invention provides an attitude compensation apparatus for a magnetic flux leakage detection probe, including: the device comprises two triaxial magnetic field measurement chips, a data processing unit and a data storage unit which are distributed in front and back;
the two triaxial magnetic field measurement chips are positioned above the tested piece and used for acquiring the magnetic field value under the current probe inclination condition;
the data processing unit is respectively connected with the two triaxial magnetic field measurement chips and is used for analyzing and processing the magnetic field value under the current probe inclination condition to obtain a defect magnetic flux leakage signal under a correct posture;
the data storage unit is connected with the data processing unit and used for storing the data of the data processing unit.
The magnetic flux leakage detection probe attitude compensation device comprises two triaxial magnetic field measurement chips, a data processing unit and a data storage unit which are distributed in the front and back direction, a tested piece is magnetized by permanent magnets on two sides of the device, a leakage magnetic field is generated when the tested piece meets defects, two groups of three-dimensional magnetic field values under the current inclination angle can be collected through the two magnetic field measurement chips, and the values are transmitted to the data processing unit and the data storage unit. The data processing unit can reversely calculate the attitude angle of the current probe by combining the measured magnetic field value and the fixed distance between the two magnetic field measurement chips, and compensate the magnetic field measured under the condition that the probe is inclined into a defect magnetic leakage signal measured under the correct attitude by utilizing the attitude angle of the current probe. The probe device in the embodiment has a simple structure, can complete magnetic leakage signal measurement and real-time compensation of the magnetic leakage signal in the inclined posture under the condition that the posture of the probe is inclined, and has a stronger signal-to-noise ratio compared with the traditional magnetic leakage detection probe.
In addition, the magnetic flux leakage detection probe attitude compensation device according to the above-described embodiment of the present invention may further have the following additional technical features:
further, in an embodiment of the present invention, the method further includes: pole shoes or steel brushes, permanent magnets, iron yokes and odometer wheels;
the pole shoes or the steel brushes are positioned on two sides of the two triaxial magnetic field measurement chips, are symmetrically distributed and are used for constraining the magnetic field distribution between the magnetic flux leakage detection probe attitude compensation device and the tested piece;
the permanent magnets comprise a permanent magnet with a downward S pole and a permanent magnet with a downward N pole, are positioned above the pole shoe or the steel brush, are symmetrically distributed on two sides of the two triaxial magnetic field measurement chips and are used for magnetizing the tested piece;
the iron yoke is positioned above the permanent magnet and the two triaxial magnetic field measurement chips and is used for constraining the magnetic field distribution in the magnetic flux leakage detection probe attitude compensation device and reducing a background magnetic field;
the mileage wheel is positioned behind the permanent magnet and used for recording the mileage distance scanned by the magnetic flux leakage detection probe on the tested piece.
Further, in an embodiment of the invention, the data processing unit is specifically configured to,
acquiring magnetic field values under the current probe inclination condition, which are measured by the two triaxial magnetic field measurement chips, wherein the magnetic field values comprise a tangential component and a normal component;
filtering two groups of tangential components in the obtained magnetic field values, and differentiating the two groups of filtered tangential components to obtain differential values of two groups of magnetic field measurement signals;
respectively marking the characteristics of the differential values of the two groups of magnetic field measurement signals to obtain flat data segments with constant characteristic differential values;
recording a first mileage distance and a second mileage distance corresponding to the defect center respectively by recording the middle points of the flat data segments as the defect center;
calculating the inclination angle of the current probe attitude according to the first mileage distance, the second mileage distance and the distance of the two magnetic field measurement chips in the normal attitude in the tangential direction;
and performing compensation calculation on the magnetic field value under the condition that the current probe is inclined by using the inclination angle of the current probe attitude to obtain a defect magnetic flux leakage signal under the correct probe attitude.
Further, in an embodiment of the present invention, the formula of the tilt angle for calculating the current probe attitude according to the first mileage distance, the second mileage distance and the distance between the two magnetic field measurement chips in the normal attitude in the tangential direction is as follows:
where θ is the angle of inclination of the current probe attitude, l1Is the first mileage distance,/2Is the second mileage distance.
Further, in an embodiment of the present invention, the performing compensation calculation on the magnetic field value under the current probe inclination condition by using the inclination angle of the current probe posture to obtain the defect leakage magnetic signal under the correct probe posture includes:
utilizing the inclination angle theta of the current probe attitude to measure the magnetic field value B under the condition that the current probe is inclinedx1c、Bx2c、Bz1cAnd Bz2cPerforming compensation calculation to obtain a defect flux leakage signal under the correct posture of the probe, wherein the defect flux leakage signal comprises a tangential component Bx1、Bx2And a normal component Bz1、Bz2Defect leakage signal B at said correct attitudex1、Bx2、Bz1、Bz2The inclination angle theta of the current probe posture and the magnetic field value B under the condition of probe inclinationx1c、Bx2c、Bz1cAnd Bz2cThe relationship of (1) is:
additional aspects and advantages of the invention will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the invention.
Drawings
The foregoing and/or additional aspects and advantages of the present invention will become apparent and readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings of which:
fig. 1 is a flowchart of a magnetic flux leakage detection probe attitude compensation method according to an embodiment of the present invention;
FIG. 2 is a schematic view of one embodiment of a probe apparatus according to one embodiment of the present invention;
FIG. 3 is a schematic diagram of position parameters of a dual magnetic measurement chip before and after inclination of a probe posture and a tested piece according to an embodiment of the invention;
FIG. 4 is a diagram illustrating the results of a flaw leakage signal with a probe in a correct attitude according to one embodiment of the present invention;
fig. 5 is a block diagram illustrating a configuration of a magnetic flux leakage detection probe attitude compensation apparatus according to an embodiment of the present invention;
reference numerals: 1-a test piece made of ferromagnetic material; 2. 3-pole shoes or steel brushes; 4-permanent magnet with S pole downward; 5-permanent magnet with N pole downward; 6-iron yoke; 7-defect; 8. 9-a three-axis magnetic field measuring chip; 10-a probe device data processing unit; 11-probe device data storage unit; 12-a circuit board; 13-a probe device; 14-mileage wheel.
Detailed Description
Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to the same or similar elements or elements having the same or similar function throughout. The embodiments described below with reference to the drawings are illustrative and intended to be illustrative of the invention and are not to be construed as limiting the invention.
The method and apparatus for compensating the attitude of the magnetic flux leakage detection probe according to the embodiment of the present invention will be described below with reference to the accompanying drawings.
First, an attitude compensation method of a magnetic flux leakage detection probe proposed according to an embodiment of the present invention will be described with reference to the accompanying drawings.
Fig. 1 is a flowchart of a magnetic flux leakage detection probe attitude compensation method according to an embodiment of the present invention.
As shown in fig. 1, the magnetic flux leakage detection probe attitude compensation method includes the following steps:
and step S1, acquiring the distance of the two triaxial magnetic field measurement chips in the normal posture in the tangential direction, wherein the tangential direction is along the magnetization direction.
In the magnetic flux leakage detection probe attitude compensation method of the embodiment of the invention, parameter measurement and compensation calculation are carried out by the magnetic flux leakage detection probe attitude compensation device.
As shown in fig. 2, the magnetic leakage detection probe posture compensation device includes two triaxial magnetic field measurement chips 8 and 9, a distance difference r of the two triaxial magnetic field measurement chips in the tangential direction is determined when the probe device is designed, and the value is kept constant in the detection process, and in consideration of an actual situation, a signal-to-noise ratio of a defect magnetic leakage signal and a lift-off difference caused by the distance difference r under an inclined situation, the chip height difference r in the embodiment of the present invention is selected within a certain range, and the minimum value is the length of the magnetic field measurement chip, generally 3mm, and the maximum value is 20 mm.
And step S2, respectively acquiring magnetic field values under the current probe inclination condition by using the two triaxial magnetic field measurement chips, wherein the magnetic field values comprise a tangential component and a normal component.
The measured magnetic field values for the current probe tilt include: tangential component B of magnetic field measured by triaxial magnetic field measurement chipx1cAnd a normal component Bz1cTangential component B of magnetic field measured by the triaxial magnetic field measuring chip IIx2cAnd a normal component Bz2c(ii) a In an embodiment of the invention, the tangential direction is the direction along the magnetization, the tangential direction being indicated by the subscript x; the normal direction is the direction vertical to the surface of the tested piece, and the normal direction is represented by subscript z; the probe attitude tilt is indicated by subscript c.
And step S3, filtering two groups of tangential components in the obtained magnetic field values, and differentiating the two groups of filtered tangential components to obtain differential values of two groups of magnetic field measurement signals.
Two groups of magnetic field tangential components B obtained by measuring two triaxial magnetic field measurement chips through a data processing unitx1cAnd Bx2cAnd performing filtering processing to filter random noise caused by a circuit and the like.
And performing differential processing on the two groups of magnetic field tangential components subjected to filtering processing through a data processing unit to obtain differential values of the two groups of magnetic field measurement signals.
In step S4, the characteristics of the differential values of the two sets of magnetic field measurement signals are marked to obtain flat data segments with constant characteristic differential values.
And step S5, recording the first mileage distance and the second mileage distance corresponding to the defect center by respectively recording the middle points of the flat data segments as the defect center.
Marking the characteristics of differential values of two groups of magnetic field measurement signals respectively through a data processing unit, such as a flat section with the maximum value, the minimum value and the differential value between the maximum value and the minimum value being constant or approximate constant, marking the midpoint of the flat section as a defect center respectively, and recording the distance l between the mileage corresponding to the flat section and the first mileage1And a second mileage distance l2。
The first mileage distance is the distance between the position of the defect midpoint obtained by calculating the magnetic field signal measured by the first triaxial magnetic field measurement chip and the scanning starting point of the magnetic flux leakage detection probe; the second mileage distance is the distance between the position of the defect midpoint calculated by the magnetic field signal measured by the second triaxial magnetic field measurement chip and the scanning starting point of the magnetic flux leakage detection probe. All the mileage distances are measured by the mileage wheel, and the mileage information of each point is associated with the magnetic field signal by the data processing unit.
And step S6, calculating the inclination angle of the current probe attitude according to the first mileage distance, the second mileage distance and the distance of the two magnetic field measurement chips in the normal attitude in the tangential direction.
The mileage distance l corresponding to the central point of the data segment differentiated into constant by the two obtained magnetic field measurement signals2And l1And two magnetsThe distance r of the field measurement chip in the tangential direction can be used for calculating the inclination angle theta of the current probe attitude by means of the data processing unit. Probe attitude tilt angle theta and midpoint distance l2And l1And the distance r satisfies the following equation:
and step S7, performing compensation calculation on the magnetic field value under the current probe inclination condition by using the inclination angle of the current probe posture to obtain a defect magnetic flux leakage signal under the correct posture of the probe.
By using the obtained inclination angle theta of the current probe, the magnetic field value B measured under the condition that the current probe is inclined can be obtainedx1c、Bx2c、Bz1cAnd Bz2cObtaining a defect leakage magnetic signal under a correct attitude through compensation calculation of the data processing unit, wherein the defect leakage magnetic signal comprises a tangential component Bx1、Bx2And a normal component Bz1、Bz2. Defect flux leakage signal B under correct attitudex1、Bx2、Bz1、Bz2Angle of inclination theta with probe attitude and magnetic field value B in case of probe inclinationx1c、Bx2c、Bz1cAnd Bz2cSatisfying the following equation:
the method provided by the embodiment of the invention can solve the problem that measurement errors are caused by the condition that the posture of the probe is inclined due to mechanical vibration, over compression of a probe bracket, uneven abrasion of a mechanical shell of the probe and the like in the actual detection process.
A solution is performed once for each defect, and the real-time tilt angle value of the probe attitude at the time of detecting the defect can be solved. And converting the magnetic field value measured under the condition that the current probe posture is inclined into a defect magnetic leakage signal under the correct posture.
The magnetic flux leakage detection probe attitude compensation method of the present invention will be described in detail below with reference to a specific embodiment.
Step 1: acquiring the distance r of the two magnetic field measurement chips in the tangential direction under the normal condition.
In the present embodiment, as shown in fig. 2, under normal conditions, the distance r between two hall chips for magnetic field measurement is 12mm, which includes 2 half widths of the hall chips 1.5mm (the magnetic field sensing point of the hall chip used in the embodiment is at the geometric center of the chip, the magnetic chip is 3mm 1mm), 1 width of the data processing unit 7mm (the data processing unit is selected as an STM32L4 single chip microcomputer by sugi corporation, the size is 7mm 1.4mm), and 2 gaps of 1 mm.
Step 2: acquiring a magnetic field value under the condition of current probe inclination by using two triaxial Hall chips, wherein the magnetic field value comprises a tangential component B of a magnetic field measured by the Hall chip Ix1cAnd a normal component Bz1cTangential component B of magnetic field measured by Hall chip twox2cAnd a normal component Bz2c。
The measured magnetic leakage signal is temporarily stored in a data storage unit through a serial communication protocol by a data processing unit STM32L4 singlechip, wherein the data storage unit is W25Q64 series of Huabang company in the embodiment, and the storage space is 64M-bit; in this embodiment, the object to be tested is a steel plate tested piece with a thickness of 12mm and containing a defect with a diameter of 8mm and a depth of 4mm, the tested piece can be an oil and gas pipeline, a rail, a storage tank bottom plate and the like, and the tested piece is magnetized by a permanent magnet with a remanence of 1.39T. The inventive probe was swept across the defect at a fixed angle during testing, the angle being 19.47 °.
And step 3: by means of a data processing unit STM32L4 single chip microcomputer, the tangential components B of the magnetic field obtained by respectively measuring two Hall chipsx1cAnd Bx2cAnd performing filtering processing to filter random noise caused by a circuit and the like.
And 4, step 4: and differentiating the two groups of magnetic field tangential components after filtering by using a data processing unit STM32L4 singlechip to obtain differential values of the two groups of magnetic field measurement signals.
And 5: marking the characteristics of differential values of two groups of magnetic field measurement signals respectively by using a data processing unit STM32L4 singlechip, such as a flat section with a maximum value, a minimum value and a differential value between the maximum value and the minimum value being constant or approximate constant, marking the midpoint of the flat section as a defect center respectively, and recording the mileage distance L corresponding to the flat section2And l1. The mileage distance l obtained in this example269.79mm and l181.17 mm.
Step 6: using the mileage distance l corresponding to the midpoint of the data segment with the obtained two magnetic field signal differential constants2And l1And the distance r of the two magnetic field measurement chips in the tangential direction, and the inclination angle theta of the current probe posture can be calculated by a data processing unit STM32L4 single chip microcomputer, as shown in FIG. 3. Probe attitude tilt angle theta and midpoint distance l2And l1And the distance r satisfies the following equation:
in this embodiment, the current attitude inclination angle calculated by the single chip microcomputer of the data processing unit STM32L4 is 18.50 degrees, actually 19.47 degrees, and the error is less than 1 degree. The embodiment of the invention well solves the problem of solving the real-time inclination angle of the probe attitude in the detection process.
And 7: by using the inclination angle theta of the current probe obtained by the method, the magnetic field value B under the condition that the current probe is inclined can be obtainedx1c、Bx2c、Bz1cAnd Bz2cAnd the defect flux leakage signal under the correct posture is obtained by the compensation calculation of the data processing unit STM32L4 singlechip, and comprises a tangential component Bx1、Bx2And a normal component Bz1、Bz2. Defect flux leakage signal B under correct attitudex1、Bx2、Bz1、Bz2Posture of probeAngle of inclination theta and magnetic field value B in case of probe inclinationx1c、Bx2c、Bz1cAnd Bz2cSatisfying the following equation:
the final result obtained by the method for compensating the posture of the flaw leakage magnetic detection probe adopted in this example is shown in fig. 5, where fig. 4(a) is a tangential component of magnetic induction intensity, and fig. 4(b) is a normal component of magnetic induction intensity. In the figure, the square and circle icons represent the measurement results obtained in the probe attitude, the curve connected by the upper triangle icon represents the compensation calculation results obtained by the method of the present embodiment, and the lower triangle is the measurement value in the correct attitude. Therefore, the method of the embodiment of the invention solves the problem of measuring the magnetic leakage signal under the inclination of the posture of the probe, and the problem of compensating the measured value under the inclination of the posture of the probe to the magnetic field value under the correct posture, and the solution model is simpler, the scientific basis is clearer, the reliability is better, and the calculation speed is high.
According to the magnetic leakage detection probe attitude compensation method provided by the embodiment of the invention, two groups of three-dimensional magnetic field values under the current inclination angle can be acquired through the two magnetic field measurement chips, the attitude angle of the current probe can be reversely calculated by combining the measured magnetic field values and the fixed distance between the two magnetic field measurement chips, and the magnetic field measured under the condition that the probe is inclined is compensated into the defect magnetic leakage signal measured under the correct attitude by utilizing the attitude angle of the current probe. The method can complete the measurement of the magnetic leakage signal and the real-time compensation of the magnetic leakage signal in the inclined posture under the condition that the posture of the probe is inclined.
Next, an attitude compensation device of a magnetic flux leakage detection probe according to an embodiment of the present invention will be described with reference to the drawings.
Fig. 5 is a schematic structural diagram of a magnetic flux leakage detection probe attitude compensation apparatus according to an embodiment of the present invention.
As shown in fig. 5, the magnetic flux leakage detection probe attitude compensation device includes: two triaxial magnetic field measurement chips 8 and 9, a data processing unit 10 and a data storage unit 11 which are distributed in front and back.
The two triaxial magnetic field measurement chips are positioned above a tested piece and used for acquiring a magnetic field value under the current condition that the probe is inclined;
the data processing unit is respectively connected with the two triaxial magnetic field measurement chips and is used for analyzing and processing the magnetic field value under the current probe inclination condition to obtain a defect magnetic flux leakage signal under the correct posture;
the data storage unit is connected with the data processing unit and used for storing the data of the data processing unit.
Further, still include: pole shoes or steel brushes, permanent magnets, iron yokes and odometer wheels;
the pole shoes or the steel brushes are positioned on two sides of the two triaxial magnetic field measurement chips, are symmetrically distributed and are used for restricting the magnetic field distribution between the magnetic flux leakage detection probe attitude compensation device and a tested piece;
the permanent magnets comprise a permanent magnet with a downward S pole and a permanent magnet with a downward N pole, are positioned above the pole shoe or the steel brush, are symmetrically distributed on two sides of the two triaxial magnetic field measurement chips and are used for magnetizing a tested piece;
the iron yoke is positioned above the permanent magnet and the two triaxial magnetic field measurement chips and is used for restricting the magnetic field distribution in the magnetic flux leakage detection probe attitude compensation device and reducing a background magnetic field;
the mileage wheel is positioned behind the permanent magnet and used for recording the distance of the mileage scanned by the magnetic flux leakage detection probe on the tested piece.
Further, the data processing unit is specifically adapted to,
acquiring magnetic field values under the current probe inclination condition measured by two triaxial magnetic field measurement chips, wherein the magnetic field values comprise a tangential component and a normal component;
filtering two groups of tangential components in the obtained magnetic field values, and differentiating the two groups of filtered tangential components to obtain differential values of two groups of magnetic field measurement signals;
respectively marking the characteristics of the differential values of the two groups of magnetic field measurement signals to obtain flat data segments with constant characteristic differential values;
respectively recording the middle points of the flat data segments as defect centers, and recording a first mileage distance and a second mileage distance corresponding to the defect centers;
calculating the inclination angle of the current probe attitude according to the first mileage distance, the second mileage distance and the distance of the two magnetic field measurement chips in the normal attitude in the tangential direction;
and (4) performing compensation calculation on the magnetic field value under the current probe inclination condition by using the inclination angle of the current probe attitude to obtain a defect magnetic flux leakage signal under the correct probe attitude.
Further, the formula of the inclination angle of the current probe attitude is calculated according to the first mileage distance, the second mileage distance and the distance of the two magnetic field measurement chips in the normal attitude in the tangential direction as follows:
where θ is the angle of inclination of the current probe attitude, l1Is the first mileage distance,/2Is the second mileage distance.
Further, the method for calculating the compensation of the magnetic field value under the current probe inclination condition by using the inclination angle of the current probe attitude to obtain the defect magnetic flux leakage signal under the correct probe attitude comprises the following steps:
utilizing the inclination angle theta of the current probe attitude to measure the magnetic field value B under the condition that the current probe is inclinedx1c、Bx2c、Bz1cAnd Bz2cPerforming compensation calculation to obtain a defect leakage magnetic signal under the correct posture of the probe, which comprises a tangential component Bx1、Bx2And a normal component Bz1、Bz2Defect flux leakage signal B at correct attitudex1、Bx2、Bz1、Bz2Inclination angle theta with current probe attitude and magnetic field value B under the condition of probe inclinationx1c、Bx2c、Bz1cAnd Bz2cThe relationship of (1) is:
it should be noted that the above explanation of the embodiment of the magnetic flux leakage detection probe attitude compensation method is also applicable to the apparatus of the embodiment, and is not repeated here.
The magnetic flux leakage detection probe attitude compensation device provided by the embodiment of the invention comprises two triaxial magnetic field measurement chips, a data processing unit and a data storage unit which are distributed in the front and back direction, a tested piece is magnetized by permanent magnets on two sides of the device, a leakage magnetic field is generated when a defect occurs, two groups of three-dimensional magnetic field values under the current inclination angle can be collected through the two magnetic field measurement chips, and the values are transmitted to the data processing unit and the data storage unit. The data processing unit can reversely calculate the attitude angle of the current probe by combining the measured magnetic field value and the fixed distance between the two magnetic field measurement chips, and compensate the magnetic field measured under the condition that the probe is inclined into a defect magnetic leakage signal measured under the correct attitude by utilizing the attitude angle of the current probe. The probe device in the embodiment has a simple structure, can complete magnetic leakage signal measurement and real-time compensation of the magnetic leakage signal in the inclined posture under the condition that the posture of the probe is inclined, and has a stronger signal-to-noise ratio compared with the traditional magnetic leakage detection probe.
Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of the present invention, "a plurality" means at least two, e.g., two, three, etc., unless specifically limited otherwise.
In the description herein, references to the description of the term "one embodiment," "some embodiments," "an example," "a specific example," or "some examples," etc., mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, the schematic representations of the terms used above are not necessarily intended to refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Furthermore, various embodiments or examples and features of different embodiments or examples described in this specification can be combined and combined by one skilled in the art without contradiction.
Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention, and that variations, modifications, substitutions and alterations can be made to the above embodiments by those of ordinary skill in the art within the scope of the present invention.
Claims (9)
1. A magnetic flux leakage detection probe attitude compensation method is characterized by comprising the following steps:
s1, acquiring the distance of the two triaxial magnetic field measurement chips in the tangential direction under the normal posture;
s2, respectively acquiring magnetic field values under the current probe inclination condition by using the two triaxial magnetic field measurement chips, wherein the magnetic field values comprise a tangential component and a normal component;
s3, filtering two groups of tangential components in the obtained magnetic field values, and differentiating the two groups of filtered tangential components to obtain differential values of two groups of magnetic field measurement signals;
s4, marking the characteristics of the differential values of the two groups of magnetic field measurement signals respectively to obtain flat data segments with constant characteristic differential values;
s5, recording a first mileage distance and a second mileage distance corresponding to the defect center by respectively recording the middle points of the flat data segments as the defect center;
s6, calculating the inclination angle of the current probe attitude according to the first mileage distance, the second mileage distance and the distance of the two magnetic field measurement chips in the normal attitude in the tangential direction;
and S7, performing compensation calculation on the magnetic field value under the current probe inclination condition by using the inclination angle of the current probe attitude to obtain a defect magnetic flux leakage signal under the correct probe attitude.
2. The magnetic flux leakage detection probe attitude compensation method according to claim 1, wherein the flat data segment whose characteristic differential value is constant includes:
the maximum value and the minimum value of the differential values of the two groups of magnetic field measurement signals and the differential between the maximum value and the minimum value are flat sections with constant or approximate constant.
3. The magnetic flux leakage detection probe attitude compensation method according to claim 1, wherein the magnetic field values under the current probe tilt condition include:
the first triaxial magnetic field measuring chip measures the tangential component B of the magnetic fieldx1cAnd a normal component Bz1cThe tangential component B of the magnetic field measured by the second triaxial magnetic field measuring chipx2cAnd a normal component Bz2c(ii) a Tangential is the direction along the magnetization, denoted by the subscript x; the normal direction is the direction perpendicular to the surface of the test piece and is denoted by the subscript z.
4. The magnetic flux leakage detection probe attitude compensation method according to claim 1, wherein the formula for calculating the tilt angle of the current probe attitude according to the first distance, the second distance and the distance in the tangential direction between the two magnetic field measurement chips in the normal attitude is as follows:
wherein theta is the current probeAngle of inclination of head attitude,/1Is the first mileage distance,/2For the second distance, r is the distance of the two magnetic field measurement chips in the tangential direction.
5. The magnetic leakage detection probe attitude compensation method according to claim 3, wherein the S7 further includes:
utilizing the inclination angle theta of the current probe attitude to measure the magnetic field value B under the condition that the current probe is inclinedx1c、Bx2c、Bz1cAnd Bz2cPerforming compensation calculation to obtain a defect flux leakage signal under the correct posture of the probe, wherein the defect flux leakage signal comprises a tangential component Bx1、Bx2And a normal component Bz1、Bz2Defect leakage signal B at said correct attitudex1、Bx2、Bz1、Bz2The inclination angle theta of the current probe posture and the magnetic field value B under the condition of probe inclinationx1c、Bx2c、Bz1cAnd Bz2cThe relationship of (1) is:
6. the utility model provides a magnetic leakage detects probe gesture compensation arrangement which characterized in that includes: the device comprises two triaxial magnetic field measurement chips, a data processing unit and a data storage unit which are distributed in front and back;
the two triaxial magnetic field measurement chips are positioned above a tested piece and used for acquiring a magnetic field value under the current probe inclination condition, wherein the magnetic field value comprises a tangential component and a normal component;
the data processing unit is respectively connected with the two triaxial magnetic field measurement chips and is used for analyzing and processing the magnetic field value under the current probe inclination condition to obtain a defect magnetic flux leakage signal under a correct posture;
the data processing unit is specifically used for acquiring the distance of the two triaxial magnetic field measurement chips in the tangential direction under the normal posture;
acquiring the magnetic field values of the current probe under the condition of inclination measured by the two triaxial magnetic field measurement chips;
filtering two groups of tangential components in the obtained magnetic field values, and differentiating the two groups of filtered tangential components to obtain differential values of two groups of magnetic field measurement signals;
respectively marking the characteristics of the differential values of the two groups of magnetic field measurement signals to obtain flat data segments with constant characteristic differential values;
recording a first mileage distance and a second mileage distance corresponding to the defect center respectively by recording the middle points of the flat data segments as the defect center;
calculating the inclination angle of the current probe attitude according to the first mileage distance, the second mileage distance and the distance of the two magnetic field measurement chips in the normal attitude in the tangential direction;
compensating and calculating the magnetic field value under the current probe inclination condition by using the inclination angle of the current probe attitude to obtain a defect magnetic flux leakage signal under the correct probe attitude;
the data storage unit is connected with the data processing unit and used for storing the data of the data processing unit.
7. The magnetic leakage detection probe attitude compensation device according to claim 6, further comprising: pole shoes or steel brushes, permanent magnets, iron yokes and odometer wheels;
the pole shoes or the steel brushes are positioned on two sides of the two triaxial magnetic field measurement chips, are symmetrically distributed and are used for constraining the magnetic field distribution between the magnetic flux leakage detection probe attitude compensation device and the tested piece;
the permanent magnets comprise a permanent magnet with a downward S pole and a permanent magnet with a downward N pole, are positioned above the pole shoe or the steel brush, are symmetrically distributed on two sides of the two triaxial magnetic field measurement chips and are used for magnetizing the tested piece;
the iron yoke is positioned above the permanent magnet and the two triaxial magnetic field measurement chips and is used for constraining the magnetic field distribution in the magnetic flux leakage detection probe attitude compensation device and reducing a background magnetic field;
the mileage wheel is positioned behind the permanent magnet and used for recording the mileage distance scanned by the magnetic flux leakage detection probe on the tested piece.
8. The magnetic flux leakage detection probe attitude compensation apparatus according to claim 6, wherein the formula for calculating the tilt angle of the current probe attitude according to the first distance, the second distance and the distance in the tangential direction between the two magnetic field measurement chips in the normal attitude is as follows:
where θ is the angle of inclination of the current probe attitude, l1Is the first mileage distance,/2For the second distance, r is the distance of the two magnetic field measurement chips in the tangential direction.
9. The magnetic leakage detection probe attitude compensation device according to claim 6, wherein the performing compensation calculation on the magnetic field value under the current probe inclination condition by using the inclination angle of the current probe attitude to obtain the defect magnetic leakage signal under the correct probe attitude comprises:
the magnetic field values under the current probe tilt condition comprise:
the first triaxial magnetic field measuring chip measures the tangential component B of the magnetic fieldx1cAnd a normal component Bz1cThe tangential component B of the magnetic field measured by the second triaxial magnetic field measuring chipx2cAnd a normal component Bz2c(ii) a Tangential is the direction along the magnetization, denoted by the subscript x; the normal direction is the direction vertical to the surface of the tested piece, and the normal direction is represented by subscript z;
utilizing the inclination angle theta of the current probe attitude to measure the magnetic field value B under the condition that the current probe is inclinedx1c、Bx2c、Bz1cAnd Bz2cPerforming compensation calculation to obtain a defect flux leakage signal under the correct posture of the probe, wherein the defect flux leakage signal comprises a tangential component Bx1、Bx2And a normal component Bz1、Bz2Defect leakage signal B at said correct attitudex1、Bx2、Bz1、Bz2The inclination angle theta of the current probe posture and the magnetic field value B under the condition of probe inclinationx1c、Bx2c、Bz1cAnd Bz2cThe relationship of (1) is:
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| CN111983013A (en) * | 2020-08-24 | 2020-11-24 | 中山大学 | Device for automatically detecting magnetic flux leakage of corrosion defects of irradiation region at top of reactor cabin |
| CN113671018B (en) * | 2021-08-10 | 2023-05-09 | 南京航空航天大学 | Filtering method for inhibiting lifting interference of steel rail magnetic flux leakage detection |
| CN114217247A (en) * | 2021-12-08 | 2022-03-22 | 北京森馥科技股份有限公司 | Correction measurement method of isotropic electromagnetic field probe |
| CN114636753A (en) * | 2022-03-09 | 2022-06-17 | 清华大学 | Magnetic flux leakage detection defect rapid quantification method based on background magnetic field balance point |
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