CN116817737A - Method and device for measuring ovality of spheroidal graphite cast iron pipe - Google Patents
Method and device for measuring ovality of spheroidal graphite cast iron pipe Download PDFInfo
- Publication number
- CN116817737A CN116817737A CN202310797237.6A CN202310797237A CN116817737A CN 116817737 A CN116817737 A CN 116817737A CN 202310797237 A CN202310797237 A CN 202310797237A CN 116817737 A CN116817737 A CN 116817737A
- Authority
- CN
- China
- Prior art keywords
- center
- cast iron
- sensor
- iron pipe
- circular ring
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- 229910001141 Ductile iron Inorganic materials 0.000 title claims abstract description 54
- 238000000034 method Methods 0.000 title claims abstract description 16
- 230000000007 visual effect Effects 0.000 claims abstract description 12
- 238000001514 detection method Methods 0.000 claims abstract description 5
- 238000009826 distribution Methods 0.000 claims description 6
- 239000011521 glass Substances 0.000 claims description 5
- 238000000605 extraction Methods 0.000 claims description 2
- 238000005259 measurement Methods 0.000 abstract description 13
- 230000002500 effect on skin Effects 0.000 abstract description 4
- 238000010586 diagram Methods 0.000 description 4
- 238000000691 measurement method Methods 0.000 description 4
- 230000006698 induction Effects 0.000 description 3
- 230000004907 flux Effects 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 230000003287 optical effect Effects 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 1
- 229910010293 ceramic material Inorganic materials 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 230000005284 excitation Effects 0.000 description 1
- 239000004744 fabric Substances 0.000 description 1
- 238000009413 insulation Methods 0.000 description 1
- 238000003754 machining Methods 0.000 description 1
- 238000003908 quality control method Methods 0.000 description 1
- 239000000523 sample Substances 0.000 description 1
Classifications
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E30/00—Energy generation of nuclear origin
- Y02E30/30—Nuclear fission reactors
Abstract
The utility model discloses a method and a device for measuring ellipticity of a ductile cast iron pipe, wherein a visual camera is arranged on a gripper of a mechanical arm, five eddy current sensors are arranged on a circular ring taking the visual camera as a circle center, so that the five sensors are distributed on the circular ring, and then the circular ring of the distributed sensors is moved to coincide with the elliptical center of the ductile cast iron pipe through the mechanical arm, so that an elliptical fitting is convenient for a subsequent establishment coordinate system. The electric vortex sensor calibrates the distance from the electric vortex sensor to the surface of the spheroidal graphite cast iron pipe through skin effect, so that the position coordinates of the five points can be obtained, then an ellipse equation of the spheroidal graphite cast iron pipe can be fitted according to the principle that the five points (any three points are not collinear) can be determined, and the ellipticity of the ellipse is calculated. The utility model is non-contact measurement, has simple structure, simple operation, high detection precision and precision reaching micron level.
Description
Technical Field
The utility model relates to the technical field of sensor measurement, in particular to a method and a device for measuring ovality of a ductile cast iron pipe.
Background
In the field of industrial manufacturing and quality control, accurate measurement and assessment of round tubes is very important. The geometry of a round tube has a critical impact on the performance and function of many applications, particularly in the areas of pipes, bearings, automotive parts, aerospace equipment, and the like. One of the important parameters is the ovality of the tube, which describes the degree of deviation between the tube cross-section and the ideal circle.
Ellipticity refers to the difference between the major and minor axes of a circular tube in a cross section perpendicular to its axis. For an ideal round tube, its ovality should be zero, meaning that its cross section is perfectly circular. However, the cross-section of the tube may be non-circular to some extent due to various factors in the manufacturing process, such as material deformation, machining errors, etc. In the past, conventional measurement methods have relied primarily on touch measurements using touch sensors such as trigger probes or micrometers. However, these methods have some limitations such as slow measurement speed, high dependence on manual operation, and damage to the surface of the round tube. Thus, researchers are increasingly interested in the development of non-contact measurement techniques.
There are a number of background techniques currently available for measuring ovality of a round tube. The following are some common techniques, optical measurements: the tube is scanned and measured using an optical sensor or vision system. This may include using a laser sensor, camera or projector, etc., to calculate ellipticity by analyzing the image or reflection of light to obtain shape data of the tube. Comparison measurement: the round tube to be measured is compared with a known shape (such as an ideal cylinder) for measurement. This may include determining the ovality of the tubular by comparing the tubular to be measured to an ideal shape using a comparison projector or comparison measurement device. Skin effect measurement: and measuring ellipticity of the circular tube by using an eddy current sensor. The eddy current sensor can detect fine changes in the surface of the circular tube by measuring current induction, so that ellipticity is calculated.
In recent years, a noncontact measurement method has been widely used. The eddy current sensor is also a commonly used non-contact measurement technique for measuring ovality of a circular tube based on skin effect. The eddy current sensor can detect fine changes in the surface of the circular tube by measuring current induction, so that ellipticity is calculated. The method does not need to be in direct contact with the surface of the round tube, and has very high measurement precision and real-time performance.
Disclosure of Invention
Aiming at the defects and actual measurement scenes in the prior art, the utility model provides a device and a method for measuring the ellipticity of spheroidal graphite cast iron by using a high-frequency reflection principle of an eddy current sensor.
The technical proposal of the utility model is as follows
And 1, installing n eddy current sensors on the periphery of a gripper of the mechanical arm, wherein n is not less than 5, so that the eddy current sensors are distributed on a circular ring taking the gripper of the mechanical arm as a circle center, simultaneously, the central axes of the eddy current sensors are intersected at the center of the circular ring, installing a vision camera at the center of the gripper of the mechanical arm, positioning the elliptical center of the spheroidal graphite cast iron pipe through a characteristic extraction method, and then moving the mechanical arm so that the intersection point of the central axes of the emission sensors of the eddy current sensors coincides with the elliptical center of the spheroidal graphite cast iron pipe.
And 2, measuring the distance from the center of the front end surface of the transmitting sensor coil of the eddy current sensor to the inner side of the spheroidal graphite cast iron to be measured, calculating the coordinates of the center of the front end surface of the transmitting sensor of each eddy current sensor relative to the ellipse center of the spheroidal graphite cast iron according to the direction of the center axis of the transmitting sensor coil of the eddy current sensor relative to the ellipse center of the spheroidal graphite cast iron and the radius of the circular ring of the distribution sensor, and similarly, calculating the coordinates of the intersection point of the center of the transmitting coil of each eddy current sensor and the inner side of the spheroidal graphite cast iron pipe to be measured relative to the ellipse center. And according to the coordinates of the five intersection points, calculating to obtain an elliptic equation.
And 3, obtaining the lengths of an elliptic short half shaft and a long half shaft through an elliptic equation, subtracting the length of the short half shaft from the length of the long half shaft, and dividing the length by the radius of a standard nodular cast iron pipe to obtain ellipticity.
Method according to claim 1, characterized in that the general equation of the ellipse is calculated from the coordinates of the five points and the ellipticity is derived, in particular the following steps: the coordinates of the five intersection points are (x) 1 ,y 1 )、(x 2 ,y 2 )、(x 3 ,y 3 )、(x 4 ,y 4 )、(x 5 ,y 5 ) The five point coordinates are brought into the general equation Ax for an ellipse 2 +Bxy+Cy 2 +dx+ey+1=0, solving for the value of A, B, C, D, E, F, and then deriving the ellipse center coordinates by the following formula:
finally, according to the obtained A, B, C, D, E, F value and the ellipse center coordinate (x 0 ,y 0 ) The shorter half shaft R is obtained by taking the following formula 1 And long half shaft R 2 Is finally passed throughCalculating ellipticity, wherein R is 0 Is the radius of a standard ductile iron pipe.
The method and the device for detecting the thickness of the ductile cast iron pipe by adopting the method according to any one of claims 1 to 2 are characterized by comprising the following parts of the eddy current sensor, a ring with distributed sensors, the ductile cast iron pipe to be detected, a heat-resistant shell, heat-resistant transparent glass, a visual camera for positioning the center of an ellipse and a mechanical arm for position adjustment.
The electric vortex sensor is arranged in the heat-resistant shell, the central axis of the transmitting coil of the electric vortex sensor faces to the transparent glass of the heat-resistant shell, five heat-resistant shells are arranged on the circular rings distributed by the sensor, and meanwhile, the central axis of the transmitting coil of the electric vortex sensor and the central axis of the circular rings distributed by the sensor are intersected.
The visual camera is arranged at the center of a ring distributed by the sensor to position the elliptical center of the spheroidal graphite cast iron. The mechanical arm for adjusting the position is a circular ring for adjusting the distribution of the sensor so that the center of the circular ring coincides with the elliptical center of the spheroidal graphite cast iron to be measured.
A device for detecting ovality of a ductile iron pipe according to claim 3 wherein the detection range of the eddy current sensor is 1-100 mm, the resolution is 0.1 μm and the linearity is 1%.
The apparatus for detecting ovality of a ductile iron pipe according to claim 4 wherein five eddy current sensors are installed on a circular ring so as to be uniformly distributed on the circular ring, 5 heat-resistant housings are respectively arranged on the circular ring, a central axis of each sensor emitting sensor coil is intersected at the center of the circular ring, and a vision camera is installed at the center of the circular ring, and the apparatus is integrally installed on a robot arm.
The whole measuring part of the electric vortex sensor consists of a transmitting sensor coil, a head part, a heat-resistant shell and a high-frequency cable;
the detection range of the eddy current sensor is 1-100 mm, the resolution is 0.1 mu m, the linearity is 1%, and the system Wen Piao is 0.05%/DEG C.
The heat-resistant shell is made of ceramic materials, and the heat-resistant transparent glass is arranged at the opening end of the heat-resistant shell, so that the heat insulation effect is achieved, and meanwhile, the measuring precision of the sensor is not affected.
The utility model has the beneficial results that:
five eddy current sensors of the same type are uniformly arranged on the circular ring and are marked as an eddy current sensor A, an eddy current sensor B, an eddy current sensor C, an eddy current sensor D and an eddy current sensor E. Meanwhile, a visual camera is arranged on a gripper of the mechanical arm, and the circular ring is arranged around the visual camera, so that the visual camera needs to be ensured to be positioned at the center of the circular ring. After the post-construction measuring platform is built, the calibration of the eddy current sensor is started, and if the calibration has errors, the calibration is carried out again until the eddy current sensor can work normally. And if the calibration has no error, starting to measure the distances between the five sensors and the spheroidal graphite cast iron pipe to be measured, and obtaining five data. And then, five data are brought into a five-point elliptic equation to determine a unique ellipse (any three points are not collinear), so that the length of a minor half axis and a major half axis of the ellipse is obtained, and finally, the ellipticity is calculated. The utility model is non-contact measurement, has simple structure, easy operation, high detection precision and precision up to micron identification.
Drawings
FIG. 1 is a three-dimensional perspective view of an integral measuring device according to the present utility model
FIG. 2 is a schematic diagram of the high frequency reflection type of the eddy current sensor in the present utility model
FIG. 3 is a schematic view of ovality calculation of a ductile iron pipe in the present utility model.
Detailed Description
The following description of the embodiments of the present utility model will be made clearly and completely with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some embodiments of the present utility model, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the utility model without making any inventive effort, are intended to be within the scope of the utility model.
Fig. 1 is a three-dimensional schematic diagram of a device for measuring ovality of a non-contact spheroidal graphite cast iron pipe. The device comprises a platform (1), a sensor distribution circular ring (2), a mechanical arm (3), a vision camera (4) and an eddy current sensor (5), and is characterized in that the platform (1) can control the spheroidal graphite cast iron pipe to be tested to overturn; the sensor distribution circular ring (2) is used for fixing five eddy current sensors; the mechanical arm (3) can adjust the position of the circular ring (2) so that the center of the circular ring coincides with the center of the spheroidal graphite cast iron pipe and the plane of the circular ring is parallel to the section of the spheroidal graphite cast iron pipe; the visual camera (4) is used for positioning the center of the ductile cast iron pipe, so that the mechanical arm can conveniently move the circular ring (2) in the next step to enable the center of the circular ring to coincide with the center of the ductile cast iron pipe; the eddy current sensor (4) is used for measuring the distance from the inner wall of the ductile cast iron pipe to the circular ring (2) in the direction of the central axis of the sensor, coordinates of five points of the ductile cast iron pipe are obtained through the distance and the radius of the circular ring (2) of the known distribution sensor, finally an elliptic equation is obtained, the ellipticity is calculated, and five eddy current sensors with the same type are arranged in the whole device.
FIG. 2 shows a high-frequency reflection schematic diagram of an eddy current sensor, wherein a transmitting sensor coil L is arranged on the inner side of a spheroidal graphite cast iron pipe to be tested 1 When in coil L 1 High frequency>1 MHz) excitation current i 1 Coil L 1 Generates an alternating magnetic flux phi 1 The magnetic field acts on the ductile cast iron pipe, but cannot penetrate the ductile cast iron pipe with a certain thickness due to skin effect, but acts only on a thin layer on the inner surface of the ductile cast iron pipe. Under the action of alternating magnetic field, induction current i 'is generated on the inner surface of the nodular cast iron pipe' 1 I.e. eddy currents. The induced current also produces an alternating magnetic flux phi' 1 And counteracts coil L 1 And the direction of the magnetic field is opposite to the original magnetic field direction of the coil. When the material of the tested object is not transformed, h can be measured 1 Is a value of (2).
Fig. 3 is a schematic diagram of calculation of ellipticity in the patent of the present utility model, and the calculation process will be fully described with reference to fig. 3. After the above steps are completed, a coordinate system is established by observing the side view and then taking the center of the circle as the origin of coordinates. Five eddy current sensors of the same model are distributed on the circular ring, namely an eddy current sensor A, an eddy current sensor B, an eddy current sensor C, an eddy current sensor D and an eddy current sensor E. The distance R from the inner wall of the circular ring of the nodular cast iron pipe to the circular ring can be obtained by the five eddy current sensors 1 、R 2 、R 3 、R 4 、R 5 . Then, the positive and negative angles of the central axis and the x axis of the electric vortex sensor are recorded as theta i Where i=1, 2, 3, 4, 5, finally according to θ i And divide intoThe radius r of the circle of the cloth sensor can be calculated to obtain the coordinate (x 1 ,y 1 ) Taking the sensor a in fig. 3 as an example, the angle of the central axis of the sensor a in fig. 3 is θ 1 Then pass formula x 1 ＝(r+R 1 )cosθ 1 ，y 1 ＝(r+R 1 )sinθ 1 Thereby obtaining the A-point coordinates (x 1 ,y 1 ) And so on to obtain the coordinates of the remaining B, C, D, E points. The five point coordinates are brought into the general equation Ax for an ellipse 2 +Bxy+Cy 2 +dx+ey+1=0, solving for the value of A, B, C, D, E, F, and then deriving the ellipse center coordinates by the following formula:
finally, according to the obtained A, B, C, D, E, F value and the ellipse center coordinate (x 0 ,y 0 ) The shorter half shaft R is obtained by taking the following formula 1 And long half shaft R 2 Is finally passed throughCalculating ellipticity, wherein R is 0 Is the radius of a standard ductile iron pipe.
Claims (5)
1. A method for measuring ovality of a ductile iron pipe, comprising the steps of:
step 1, installing n eddy current sensors on the periphery of a gripper (3) of a mechanical arm, wherein n is not less than 5, the eddy current sensors (5) are distributed on a circular ring (2), meanwhile, the central axes of the eddy current sensors (5) are intersected with the circular ring (2), then, installing a vision camera (4) in the center of the gripper of the mechanical arm, positioning the elliptical center of a nodular cast iron pipe through a characteristic extraction method, and then, moving the mechanical arm so that the central axes of the emission sensors of the eddy current sensors are intersected with the elliptical center of the nodular cast iron pipe;
and 2, measuring the distance from the center of the front end surface of the coil of the transmitting sensor of the electric vortex sensor to the inner side of the spheroidal graphite cast iron to be measured, calculating the coordinates of the center of the front end surface of the transmitting sensor of each electric vortex sensor relative to the ellipse center of the spheroidal graphite cast iron according to the direction of the center axis of the coil of the transmitting sensor of the electric vortex sensor relative to the ellipse center of the spheroidal graphite cast iron, and similarly, calculating the coordinates of the intersection point of the center of the transmitting coil of each electric vortex sensor and the inner side of the spheroidal graphite cast iron pipe to be measured relative to the ellipse center. Obtaining an elliptic equation according to the coordinates of the five intersection points;
and 3, obtaining the lengths of an elliptic short half shaft and a long half shaft through an elliptic equation, subtracting the length of the short half shaft from the length of the long half shaft, and dividing the length by the radius of a standard nodular cast iron pipe to obtain ellipticity.
2. Method according to claim 1, characterized in that the general equation of the ellipse is calculated from the coordinates of the five points and the ellipticity is derived, in particular the following steps:
the coordinates of the five intersection points are (x) 1 ,y 1 )、(x 2 ,y 2 )、(x 3 ,y 3 )、(x 4 ,y 4 )、(x 5 ,y 5 ) The five point coordinates are brought into the general equation Ax for an ellipse 2 +Bxy+Cy 2 +dx+ey+1=0, solving for the value of A, B, C, D, E, F, and then deriving the ellipse center coordinates by the following formula:
based on the solved A, B, C, D, E, F value and the ellipse center coordinates (x 0 ,y 0 ) The shorter half shaft R is obtained by taking the following formula 1 And long half shaft R 2 Is finally passed throughCalculating ellipticity, wherein R is 0 Is the radius of a standard ductile iron pipe;
3. the device for detecting the ovality of the ductile cast iron pipe by adopting the method according to any one of claims 1 to 2 is characterized by comprising the following parts of the eddy current sensor, a ring with distributed sensors, the ductile cast iron pipe to be detected, a heat-resistant shell, heat-resistant transparent glass, a visual camera for positioning the center of the ellipse and a mechanical arm for adjusting the position;
the electric vortex sensor is arranged in the heat-resistant shell, the central axis of the transmitting coil of the electric vortex sensor faces to the transparent glass of the heat-resistant shell, five heat-resistant shells are arranged on the circular rings distributed by the sensor, and the central axis of the transmitting coil of the electric vortex sensor and the central axis of the circular rings distributed by the sensor are intersected;
the visual camera is arranged at the center of a ring distributed by the sensor to position the elliptical center of the spheroidal graphite cast iron. The mechanical arm for adjusting the position is a circular ring for adjusting the distribution of the sensor so that the center of the circular ring coincides with the elliptical center of the spheroidal graphite cast iron to be measured.
4. A device for detecting ovality of a ductile iron pipe according to claim 3 wherein the detection range of the eddy current sensor is 1-100 mm, the resolution is 0.1 μm and the linearity is 1%.
5. The apparatus for detecting ovality of ductile iron pipe according to claim 4 wherein a visual camera is installed on the robot arm grip, a circular ring is installed around the visual camera, five eddy current sensors are installed on the circular ring to be distributed on the circular ring, 5 heat-resistant housings are respectively arranged on the circular ring, and a central axis of each sensor emitting sensor coil is intersected at the center of the circular ring.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202310797237.6A CN116817737A (en) | 2023-07-03 | 2023-07-03 | Method and device for measuring ovality of spheroidal graphite cast iron pipe |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202310797237.6A CN116817737A (en) | 2023-07-03 | 2023-07-03 | Method and device for measuring ovality of spheroidal graphite cast iron pipe |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN116817737A true CN116817737A (en) | 2023-09-29 |
Family
ID=88112349
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202310797237.6A Pending CN116817737A (en) | 2023-07-03 | 2023-07-03 | Method and device for measuring ovality of spheroidal graphite cast iron pipe |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN116817737A (en) |
-
2023
- 2023-07-03 CN CN202310797237.6A patent/CN116817737A/en active Pending
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| WO2022041986A1 (en) | In-place non-contact detection method for shaft workpiece | |
| JP6254535B2 (en) | Device for measuring the internal or external contour of tubular components | |
| CA2718224C (en) | Apparatus, system, and method for measuring thread features on pipe or tube end | |
| US7440089B2 (en) | Method of measuring decentering of lens | |
| TWI396825B (en) | Method of measuring three-dimensional shape | |
| CN1094191C (en) | Method and apparatus for non-contact measuring thickness of non-metal coating on surface of metal matrix | |
| JP4762851B2 (en) | Cross-sectional shape detection method and apparatus | |
| CN116817737A (en) | Method and device for measuring ovality of spheroidal graphite cast iron pipe | |
| CN113446952A (en) | Online non-contact shaft diameter measuring method | |
| CN115451777A (en) | Method for measuring wall thickness of pipe end of steel pipe | |
| JP2010256277A (en) | Method and apparatus for measuring outer shape of workpiece | |
| Miao et al. | A vision measurement method for the gear shaft radial runout with line structured light | |
| JP2746511B2 (en) | Method for measuring orientation flat width of single crystal ingot | |
| CN215932146U (en) | Comprehensive detector for measuring geometric dimension of pressure-bearing equipment | |
| CN112857197B (en) | Rotating electromagnetic field non-ferromagnetic material crack size measurement method | |
| JPH0465610A (en) | Shape measuring instrument for tube body | |
| CN113310439A (en) | Method and system for detecting surface roughness of spherical shell part based on white light confocal sensor | |
| JPH05240621A (en) | Instrument for measuring outer diameter and wall thickness of pipe | |
| JPH06307845A (en) | Roll alignment measuring method | |
| CN116242239B (en) | Method and device for detecting thickness of nodular cast iron pipe | |
| CN115090740B (en) | Measuring method for measuring spinning forming precision of curved surface piece on line | |
| JPH01232203A (en) | Shape measuring instrument for tube body | |
| CN117804357B (en) | Deep hole detection device and detection method based on laser reflection | |
| Song et al. | Research on multi-sensor measurement system and evaluation method for roundness and straightness errors of deep-hole parts | |
| CN114838695B (en) | Aviation conduit bending section measuring method based on multi-camera measuring system |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication |