An ellipticity standard part applied to the measurement of bending deformation quality of a catheter and a measurement method

Abstract

This invention discloses an ellipticity standard component and measurement method for measuring the quality of duct bending deformation. The standard component includes several grooves cut from top to bottom on the surface of a cylindrical body. The cross-sections at the groove locations are elliptical, and the ellipticity of each elliptical cross-section is unequal. Each elliptical cross-section and the groove wall along the central axis constitute several elliptical cylinder standard components. A coordinate measuring machine (CMM) is used to calibrate the standard component: First, coordinate points are collected on the outer cylindrical surface of the standard component, and the central axis is fitted to obtain it. Then, coordinate points are collected on the elliptical cylinder surface of the standard component and projected onto a plane with the central axis as the normal vector, and the geometric parameters of the elliptical cylinder are fitted to obtain it. Finally, the ellipticity corresponding to each elliptical cylinder is calculated, completing the fabrication of the ellipticity standard component. This invention establishes a standard for the detection and evaluation of ellipticity after duct bending deformation and proposes a method for measuring ellipticity using a coordinate measuring machine, which has good versatility and high accuracy.

Description

Technical Field

[0001] This invention relates to the field of aerospace manufacturing, specifically to an ellipticity standard and measurement method for measuring the quality of duct bending deformation. Background Technology

[0002] Due to their excellent physical properties, conduits have been widely used in various critical equipment within aerospace systems. Aerospace conduits are mostly curved conduits, and the bending process involves continuous elasto-plastic deformation, a complex stress process influenced by multiple factors. When the conduit is bent, the outer side is stretched and lengthened, while the inner side is compressed and shortened. Under the combined action of stresses on both the inner and outer sides, the cross-section of the conduit at the bend will be distorted, taking on an elliptical shape. In the manufacturing process, the ellipticity of the cross-section is generally used to measure the degree of distortion. The greater the ellipticity of the cross-section at the bend, the greater the degree of distortion, and the worse the mechanical properties of the conduit, thus seriously affecting the manufacturing quality of the product. The ellipticity of the conduit has become an important indicator for evaluating the quality of its bending deformation.

[0003] Currently, there are many methods for detecting the ellipticity of catheters, including manual inspection methods and visual analysis methods. Among them, visual analysis methods, based on computer vision principles, offer advantages such as non-contact operation, high precision, and high stability, and have become the mainstream development direction for ellipticity detection. However, the performance of this type of method is difficult to evaluate, and there is no unified standard for measurement. Furthermore, due to the unique shape of the curved sections of catheters, general geometric standards are insufficient to characterize ellipticity parameters, let alone evaluate the measurement performance of ellipticity. Therefore, this field urgently needs an ellipticity standard to evaluate the detection capability of catheter bending deformation quality. Summary of the Invention

[0004] To address the shortcomings of existing technologies, the technical problem to be solved by this invention is to provide an ellipticity standard component and measurement method for measuring the quality of duct bending deformation. The standard value of its ellipticity is calibrated using a coordinate measuring machine, thereby solving the problem that existing standard components cannot evaluate the ellipticity measurement capability.

[0005] The technical solution adopted by the present invention to achieve the above objectives is as follows:

[0006] An ellipticity standard component for measuring the bending deformation quality of conduits includes: a cylindrical body; the surface of the cylindrical body has several grooves of unequal width and depth from top to bottom, the cross-section of the grooves on the cylinder is elliptical, and the ellipticity of each elliptical cross-section is unequal; each elliptical cross-section and the groove wall along the central axis form several elliptical cylinders; each elliptical cylinder is coaxial with the cylindrical body; each elliptical cylinder is a standard component with unequal ellipticity.

[0007] The difference between the major and minor axes of the elliptical cross-section at each slot location is not equal.

[0008] The major axes of the elliptical cross sections are equal, while the minor axes are unequal, or the major axes are unequal, while the minor axes are equal.

[0009] The cylindrical body is made of metal.

[0010] The cylindrical body is made of aluminum alloy.

[0011] The surface roughness of the cylindrical body and the elliptical cylinder is less than 3.2 mm.

[0012] The surface of the standard part is deburred and processed.

[0013] The multi-segment elliptical cylinder standard component is used as the object being measured to determine the accuracy of its ellipticity measurement value. If the measurement value exceeds the standard value error range, the ellipticity measurement is determined to be inaccurate.

[0014] A method for measuring the standard ellipticity value of an ellipticity standard component used in measuring the quality of duct bending deformation, wherein the ellipticity of the standard component with varying ellipticity is calculated by collecting coordinates of data points on the surface of the standard component using a coordinate measuring machine, and then calculating the standard value of the ellipticity parameter of the standard component, including the following steps:

[0015] (1) After completing the stylus calibration using a metrology-grade coordinate measuring machine, fix the standard part within the measurement range to ensure that all points on the surface of the standard part can be measured.

[0016] (2) Collect m locations uniformly across the cross-section of the cylindrical body, denoted as p. i (i=1,…,m), the least squares method is used to fit the cylinder, and the direction vector ν of the central axis of the cylinder and a point p on the axis are calculated;

[0017] (3) Collect n position points at equal intervals around the axis at the j-th cross section of the elliptical cylinder, denoted as p. jk (k = 1, ..., n); Set the position point p jk Project the vector onto a plane passing through point p and perpendicular to vector ν, and calculate its projection point p′. jk .

[0018] (4) Based on the acquisition location point p′ jk The three-dimensional coordinates are used to fit the ellipse using the least squares circle method, and the major and minor axes of the j elliptical cylinders are calculated. The major axes are denoted as a. j (j = 1, 2, 3, N), with the minor axis denoted as b. j (j=1,2,3,N). Then, what is the nominal diameter d of the N segments of the elliptical cylinder? j The calculation is as follows:

[0019] d j =(a j +b j ) / 2

[0020] (5) Each elliptical cylinder of the standard part represents a type of conduit ellipticity, whose ellipticity Δ j (j=1,2,3,N) is calculated as follows:

[0021]

[0022] The ellipticity measurement value Δ of the current elliptical cross section j This is the standard value for the j-th ellipticity standard part.

[0023] This multi-segment elliptical cylinder standard is used as the object of measurement to measure its ellipticity and compare it with the standard value to evaluate the accuracy of other methods to see if it is within the error range.

[0024] The present invention has the following beneficial effects and advantages:

[0025] 1. The method of the present invention designs an ellipticity standard for measuring the bending deformation quality of catheters. It adopts a round bar structure, which can better characterize the geometric features of catheters, is applicable to most measurement methods, and has good versatility.

[0026] 2. The method of the present invention designs an ellipticity standard for measuring the bending deformation quality of catheters. It adopts a segmented elliptical cylindrical structure, which can represent different catheter ellipticities and evaluate the measurement performance of different catheter ellipticity detection methods.

[0027] 3. The ellipticity standard part measurement method of the present invention projects the data points on the surface of the elliptical cylinder along the central axis direction into the same plane, and then performs ellipse fitting calculation. This solves the problem that coordinate measuring equipment cannot accurately collect radial section data points of the cylinder, and the ellipticity index has high accuracy and strong standardization. Attached Figure Description

[0028] Figure 1 This is a front view of an ellipticity standard component used for measuring the bending deformation quality of a conduit, as described in this invention.

[0029] Figure 2 This is a top view of an ellipticity standard component used for measuring the bending deformation quality of a conduit, as described in this invention.

[0030] Figure 3 This is a schematic diagram of data acquisition using a coordinate measuring machine in a method for measuring the ellipticity of a standard component used to measure the bending deformation quality of a conduit. Detailed Implementation

[0031] To make the above-mentioned objects, features, and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a thorough understanding of the present invention. However, the present invention can be implemented in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of the invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0032] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.

[0033] like Figures 1-2 As shown, an ellipticity standard component for measuring the bending deformation quality of conduits includes a round bar as the main body of the standard component. The bar is a standard cylinder with several grooves machined on its surface. The cross-sections at the groove locations are elliptical, and the ellipticity of each elliptical cross-section is unequal. Each elliptical cross-section and the groove wall along the central axis form several elliptical cylinders. The difference between the major and minor axes of each elliptical cylinder is different, and they share the same central axis as the round bar. Two cylinders of different diameters are machined on one side of the round bar for fixing or clamping, facilitating measurement. Each elliptical cylinder is a standard component with unequal ellipticity.

[0034] The round bar is made of metal, specifically aluminum alloy, and has a length of 500mm, an outer surface diameter of 65mm, a surface roughness of less than 3.2mm, and all edges are chamfered with an angle of 45° and a right-angle side length of 0.3mm.

[0035] The round bar is machined with four elliptical cylinders, which are evenly spaced along the central axis with a spacing of 19.4 mm. The first elliptical cylinder is 20 mm away from one end face of the round bar along the axial direction. The axial width of each of the four elliptical cylinders is 30 mm, the major axis length of each radial section is 62 mm, and the minor axis lengths of the radial sections are 58 mm, 59 mm, 60 mm, and 61 mm, respectively. The surface roughness is less than 3.2 mm.

[0036] The surface of the ellipticity standard part is deburred and blackened to reduce reflection.

[0037] like Figure 3 As shown, the ellipticity measurement method of an ellipticity standard component used for measuring the quality of duct bending deformation in this invention includes the following steps:

[0038] (1) After completing the stylus calibration using a metrology-grade coordinate measuring machine, fix the standard part within the measurement range to ensure that all points on the surface of the standard part can be measured.

[0039] (2) On the outermost cylindrical surface (largest diameter) of the standard part, collect m location points evenly, denoted as p. i (i=1,…,m), the cylinder is fitted using the least squares method to calculate the direction vector ν of the central axis of the cylinder and a point p on the axis.

[0040] (3) Collect n location points at equal intervals around the axis on the surfaces of the four elliptical cylinders, respectively, and denot them as p. jk (j=1,2,3,4)(k=1,…,n). Position point p jk The projection onto the plane passing through point p and perpendicular to vector ν can be calculated using the following formulas (1)-(2), denoted as p′. jk :

[0041]

[0042]

[0043]

[0044]

[0045] (4) Based on the acquisition location point p j ′ k The three-dimensional coordinates are used to fit an ellipse using the least squares circle method, and the major and minor axes of the four elliptical cylinders are calculated. The major axis is denoted as a. j (j=1,2,3,4), with the minor axis denoted as b. j (j=1,2,3,4). Then, what is the nominal diameter d of the four elliptical cylinder segments? j It can be calculated as:

[0046] d j =(a j +b j ) / 2 (5)

[0047] (5) Each elliptical cylinder of the standard part can represent a type of conduit ellipticity, whose ellipticity Δ j (t=1,2,3,4) can be calculated as:

[0048]

[0049] Here, the ellipticity measurement value of the standard part is the standard value of the ellipticity of that standard part.

[0050] Example:

[0051] An ellipticity standard part is manufactured according to the method of this invention, with the calibration parameters m set to 150 and n set to 50. After manufacturing, the standard part has elliptical cylinders with major axis standard values ​​of 62.0397 mm, 62.0793 mm, 62.0918 mm, and 62.0760 mm, minor axis standard values ​​of 61.0897 mm, 60.0904 mm, 59.1102 mm, and 58.1068 mm, and ellipticity standard values ​​of 1.5431%, 3.256%, 4.92%, and 6.6053%, respectively.

[0052] The ellipticity standard of this invention is a calibration component for evaluating ellipticity measurement equipment or methods. It is used to verify the accuracy of ellipticity measurement equipment or methods and does not actually simulate a bent conduit to scale. When this ellipticity standard is used as the measurement object, and the obtained measurement value conforms to the error range (exceeding this range indicates non-compliance), it can be determined that the conduit testing equipment or method is sufficiently accurate, and the measuring equipment or method can be used to measure the ellipticity of bends with actual bending deformation. In summary, the method of this invention provides an ellipticity standard and ellipticity measurement method applied to the measurement of conduit bending deformation quality, which has good versatility and strong standardization, and can be used to evaluate the ellipticity measurement capability of conduit testing equipment.

Claims

1. An ellipticity standard for measuring the bending deformation quality of conduits, characterized in that, include: A cylindrical body; the surface of the cylindrical body has several grooves of varying widths and depths from top to bottom, the cross-section of the grooves on the cylinder is elliptical, and the ellipticity of each elliptical cross-section is different; each elliptical cross-section and the groove wall along the central axis form several elliptical cylinders; each elliptical cylinder is coaxial with the cylindrical body; each elliptical cylinder is a standard part with unequal ellipticity.

2. The ellipticity standard component for measuring the bending deformation quality of conduits according to claim 1, characterized in that, The difference between the major and minor axes of the elliptical cross-section at each slot location is not equal.

3. An ellipticity standard for measuring the bending deformation quality of a conduit according to claim 1 or 2, characterized in that, The major axes of each of the elliptical cross sections are equal, while the minor axes are unequal, or the major axes are unequal, while the minor axes are equal.

4. The ellipticity standard component for measuring the bending deformation quality of conduits according to claim 1, characterized in that, The cylindrical body is made of metal.

5. The ellipticity standard component for measuring the bending deformation quality of conduits according to claim 4, characterized in that, The cylindrical body is made of aluminum alloy.

6. The ellipticity standard component for measuring the bending deformation quality of conduits according to claim 1, characterized in that, The surface roughness of the cylindrical body and the elliptical cylinder is less than 3.2 mm.

7. The ellipticity standard component for measuring the bending deformation quality of conduits according to claim 1, characterized in that, The surface of the standard part is deburred and processed.

8. The ellipticity standard component for measuring the bending deformation quality of conduits according to claim 1, characterized in that, The aforementioned elliptical cylindrical standard parts are used as the measured object to measure the accuracy of its ellipticity measurement value. If the measurement value exceeds the error range of the standard value, the ellipticity measurement is determined to be inaccurate.

9. The method for measuring the ellipticity standard value of an ellipticity standard component applied to the measurement of duct bending deformation quality according to claim 1, characterized in that, The ellipticity of each of the aforementioned standard parts with unequal ellipticity is determined by collecting the coordinates of data points on the surface of the standard part using a coordinate measuring machine, and calculating the standard value of the ellipticity parameter of the standard part, including the following steps: (1) After completing the stylus calibration using a metrology-grade coordinate measuring machine, fix the standard part within the measurement range to ensure that all points on the surface of the standard part can be measured. (2) Collect m locations uniformly across the cross-section of the cylindrical body, denoted as p. i (i=1,…,m), the least squares method is used to fit the cylinder, and the direction vector ν of the central axis of the cylinder and a point p on the axis are calculated; (3) Collect n position points at equal intervals around the axis at the j-th cross section of the elliptical cylinder, denoted as p. jk (k = 1, ..., n); Set the position point p jk Project the vector onto a plane passing through point p and perpendicular to vector ν, and calculate its projection point p′. jk； (4) Based on the acquisition location point p′ jk The three-dimensional coordinates are used to fit the ellipse using the least squares circle method, and the major and minor axes of the j elliptical cylinders are calculated. The major axes are denoted as a. j (j = 1, 2, 3, N), with the minor axis denoted as b. j (j=1,2,3,N); then, what is the nominal diameter d of the N segments of the elliptical cylinder? j The calculation is as follows: d j =(a j +b j ) / 2 (5) Each elliptical cylinder of the standard part represents a type of conduit ellipticity, whose ellipticity Δ j (j=1,2,3,N) is calculated as follows: The ellipticity measurement value Δ of the current elliptical cross section j This is the standard value for the j-th ellipticity standard part; Multiple segments of this elliptical cylindrical standard part are used as the object of measurement to measure its ellipticity measurement value and compare it with the standard value to evaluate the accuracy of other methods to see if it is within the error range.

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