CN115060153A - Method and device for measuring dynamic radius of precision centrifuge based on strain gauge - Google Patents
Method and device for measuring dynamic radius of precision centrifuge based on strain gauge Download PDFInfo
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- CN115060153A CN115060153A CN202210649935.7A CN202210649935A CN115060153A CN 115060153 A CN115060153 A CN 115060153A CN 202210649935 A CN202210649935 A CN 202210649935A CN 115060153 A CN115060153 A CN 115060153A
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
- G01B7/00—Measuring arrangements characterised by the use of electric or magnetic techniques
- G01B7/12—Measuring arrangements characterised by the use of electric or magnetic techniques for measuring diameters
- G01B7/125—Measuring arrangements characterised by the use of electric or magnetic techniques for measuring diameters of objects while moving
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01P—MEASURING LINEAR OR ANGULAR SPEED, ACCELERATION, DECELERATION, OR SHOCK; INDICATING PRESENCE, ABSENCE, OR DIRECTION, OF MOVEMENT
- G01P21/00—Testing or calibrating of apparatus or devices covered by the preceding groups
- G01P21/02—Testing or calibrating of apparatus or devices covered by the preceding groups of speedometers
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Abstract
The invention relates to a method for measuring the dynamic radius of a precision centrifuge based on a strain gauge, which comprises the following steps: mounting a centrifugal machine table board on a shaft system, and determining that the end surface of one side, close to the shaft system, of a load mounting surface on the centrifugal machine table board is a radius datum plane; sequentially arranging a plurality of strain gauges on a table board of the centrifuge along the radius direction, wherein one end of a first strain gauge farthest from a shaft system is superposed with a radius reference surface; when the centrifuge is static, determining that the tabletop of the centrifuge is an equivalent slender rod with a uniform section along the radial direction; when the centrifuge rotates, the equivalent slender rod is divided into a plurality of micro-segments, and the deformation of any one of the length dr and the micro-segment at the radius r is determined as the strain value of the strain gauge; and determining the dynamic radius of the centrifuge according to the sum of the deformation of each micro-segment. The method and the device for measuring the dynamic radius of the precision centrifuge based on the strain gauge aim to solve the problems of complex system and high cost caused by higher requirements on hardware and software when the micrometer is used for measuring the dynamic radius of the precision centrifuge.
Description
Technical Field
The invention relates to the technical field of precision instrument measurement, in particular to a method and a device for measuring a dynamic radius of a precision centrifuge based on a strain gauge.
Background
The high-precision centrifuge is applied to the calibration and calibration of the accelerometer, and the formula a is omega 2 (r 0 +Δr)cos(α 0 +Δα)cosβ+gsin(α 0 +Δα)+gsinγsin(ωt)±2ωω e rsin θ. The dynamic radius Δ r has a large influence on the output angular velocity, so dynamic radius measurement is an important component of high-precision centrifuges.
In the existing measuring method, dynamic radius is usually measured in real time through a micrometer, and based on different measuring principles, the micrometer can be installed on a stator part of a centrifuge and also can be installed on a rotor part of the centrifuge. However, the stator type micrometer needs to accurately acquire a certain specified outer diameter of the table top of the centrifuge, which puts higher requirements on sampling frequency and acquisition algorithm; the rotor type micrometer needs to be matched with a high-precision measuring rod measuring ring mechanism for use, and provides higher requirements for machining, assembling and checking mechanical parts. In conclusion, the micrometer-based dynamic radius measurement of the precision centrifuge has higher requirements on hardware and software, so that the complexity and the cost of the system are increased.
Therefore, the inventor provides a method and a device for measuring the dynamic radius of a precision centrifuge based on a strain gauge.
Disclosure of Invention
(1) Technical problem to be solved
The embodiment of the invention provides a method and a device for measuring the dynamic radius of a precision centrifuge based on a strain gauge, which solve the technical problems of complex system and high cost caused by higher requirements on hardware and software for measuring the dynamic radius of the precision centrifuge based on a micrometer.
(2) Technical scheme
The invention provides a method for measuring a dynamic radius of a precision centrifuge based on a strain gauge, which comprises the following steps:
mounting a centrifugal machine table board on a shaft system, and determining that the end surface of a load mounting surface on the centrifugal machine table board close to one side of the shaft system is a radius datum plane;
sequentially arranging a plurality of strain gauges on the table board of the centrifuge along the radius direction, wherein one end of a first strain gauge farthest from the shaft system is superposed with the radius reference surface;
when the centrifuge is static, determining that the table top of the centrifuge is an equivalent slender rod with a uniform cross section along the radial direction;
when the centrifuge rotates, dividing the equivalent slender rod into a plurality of micro-segments, and determining the deformation of any micro-segment with the length dr and positioned at the radius r as the strain value of the strain gauge;
and determining the dynamic radius of the centrifuge according to the sum of the deformation of each micro-segment.
Further, set gradually a plurality of foil gauges along the direction of radius on the centrifuge mesa, keep away from the one end of the farthest first foil gauge of shafting with the coincidence of radius reference surface specifically is:
the strain gauges are sequentially arranged and attached to the table top of the centrifuge at set intervals along the radial direction of the scribed line, and one end of the first strain gauge is overlapped with the radius reference plane.
Further, when the centrifuge is at rest, it is determined that the centrifuge table is an equivalent slender rod with a uniform cross section along the radial direction, specifically:
the centrifuge deck is defined along a radial score line as an equivalent elongated bar of length R that changes in length to R' as the centrifuge rotates.
Further, when the centrifuge rotates, the equivalent slender rod is divided into a plurality of micro-segments, and the deformation of the micro-segment with any length dr and at the radius r is determined as the strain value of the strain gauge, specifically:
and dividing the equivalent slender rod into a plurality of micro-segments, wherein when the centrifuge rotates, the deformation of any one long dr and the micro-segment at the radius r is dl, and the strain value is epsilon.
Further, the determining the dynamic radius of the centrifuge according to the sum of the deformations of each micro-segment specifically includes the following steps:
obtaining a function curve of the strain value epsilon and the radius r of the micro-segment by cubic spline interpolation fitting;
integrating the epsilon dr from R to 0 to R to obtain the deformation amount of the static radius R; the deformation is the dynamic radius Δ R.
Further, the distance between two adjacent strain gauges is measured and calibrated through a standard gauge block.
Further, the measurement accuracy of the dynamic radius of the centrifuge is positively correlated with the number of the strain gauges.
Further, the measurement accuracy of the dynamic radius of the centrifuge is inversely related to the dimension of the strain gauge in the radial direction.
The invention provides a strain gage-based dynamic radius measuring device of a precision centrifuge, which comprises a centrifuge table board, a shaft system, a strain gage, a radius reference surface and a load mounting surface, wherein the strain gage is arranged on the centrifuge table board;
the centrifugal machine table board is arranged on the shaft system, the load mounting surface is positioned at the end part of the centrifugal machine table board, and the radius reference surface is the end surface of one side, close to the shaft system, of the load mounting surface;
the plurality of strain gauges are sequentially arranged on the table board of the centrifuge along the radius direction, and one end of the strain gauge which is farthest away from the shaft system is coincided with the radius reference surface.
(3) Advantageous effects
In summary, the dynamic radius is obtained based on physical modeling and numerical analysis by measuring the strain value of each strain gauge on the working radius. The method has the advantages of simple principle, accurate measurement, lower requirement on hardware and software, and capability of effectively reducing the complexity and cost of the system.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings needed to be used in the embodiments of the present invention will be briefly described below, and it is obvious that the drawings described below are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without creative efforts.
FIG. 1 is a schematic flow chart of a method for measuring a dynamic radius of a precision centrifuge based on a strain gauge according to an embodiment of the present invention;
FIG. 2 is an application scenario diagram of a precision centrifuge dynamic radius measurement based on a strain gauge provided in an embodiment of the present invention;
fig. 3 is a partially enlarged schematic view of fig. 2.
In the figure:
1-a table top; 2-shafting; 3-a strain gauge; 4-radius datum plane; 5-load mounting surface; 6-radial scale.
Detailed Description
The embodiments of the present invention will be described in further detail with reference to the drawings and examples. The following detailed description of the embodiments and the accompanying drawings are provided to illustrate the principles of the invention and are not intended to limit the scope of the invention, i.e., the invention is not limited to the embodiments described, but covers any modifications, alterations, and improvements in the parts, components, and connections without departing from the spirit of the invention.
It should be noted that the embodiments and features of the embodiments in the present application may be combined with each other without conflict. The present application will be described in detail below with reference to the embodiments with reference to the attached drawings.
Fig. 1 is a schematic flow chart of a method for measuring a dynamic radius of a precision centrifuge based on a strain gauge according to an embodiment of the present invention, where the method may include the following steps:
s100, mounting a centrifugal machine table board on a shaft system, and determining that the end surface of one side, close to the shaft system, of a load mounting surface on the centrifugal machine table board is a radius datum plane;
s200, sequentially arranging a plurality of strain gauges on a table board of the centrifugal machine along the radius direction, wherein one end of a first strain gauge farthest from a shaft system is superposed with a radius reference surface;
s300, when the centrifuge is static, determining that the table top of the centrifuge is an equivalent slender rod with a uniform cross section along the radial direction;
s400, when the centrifuge rotates, dividing the equivalent slender rod into a plurality of micro-segments, and determining the deformation of any micro-segment with the length dr and the radius r as the strain value of the strain gauge;
and S500, determining the dynamic radius of the centrifuge according to the sum of the deformation of each micro-segment.
In the above embodiment, the centrifuge table top 1 is installed on the shaft system 2, the load installation surface 5 is located at the end of the centrifuge table top 1, and the radius reference surface 4 is the end surface of the load installation surface 5 close to one side of the shaft system 2; when the centrifugal machine is static, the distance between the radius reference surface 4 and the axis of the shaft system 2 is the static radius R of the centrifugal machine; when the centrifugal machine works, the shaft system 2 rotates to drive the table board 1 to rotate, the distance between the radius reference surface 4 and the axis of the shaft system 2 changes into R ', and the dynamic radius delta R is R' -R.
The strain gauges 3 are adhered to the table top 1 of the centrifuge and are uniformly distributed along the radial scribed lines 6, and the number of the strain gauges is N. Two adjacent strain gauges 3 are separated by h, and one end of the first strain gauge 3 coincides with the radius reference surface 4. And recording strain values epsilon of each strain gage 3 when the centrifuge table top 1 rotates at the rated rotation speed omega, wherein epsilon L is the deformation of each strain gage 3 along the radial direction, as shown in FIG. 3, the strain value epsilon is the strain value of the radial scale line 6 of the radius reference surface 4 along the radial direction because the sizes L and D of the strain gages 3 are very small compared with the static radius R and can be ignored.
As an optional implementation manner, in step S200, the multiple strain gauges are sequentially arranged on the tabletop of the centrifuge along the radial direction, and one end of the first strain gauge farthest away from the shaft system coincides with the radius reference surface, specifically:
the plurality of strain gauges are sequentially arranged and attached to the table top of the centrifuge at set intervals along the radial direction scribed line, and one end of the first strain gauge is overlapped with the radius reference plane. Wherein, such a design can further improve the precision of measurement. Theoretically, when the set distance between two adjacent strain gauges tends to zero, the measurement result approaches the true value infinitely.
As an alternative embodiment, in step S300, when the centrifuge is at rest, the centrifuge table is determined to be an equivalent slender rod with a uniform cross section along the radial direction, specifically:
the centrifuge deck is defined along the radial score line as an equivalent elongated bar of length R, which becomes R' in length as the centrifuge rotates.
The static radius R of the centrifuge is measured by inverse algorithm according to "calibration standard of precision centrifuge of linear accelerometer", and is not described herein again.
As an alternative embodiment, in step S400, when the centrifuge rotates, the equivalent elongated rod is divided into a plurality of micro segments, and the deformation of any micro segment with a length dr and located at the radius r is determined as the strain value of the strain gauge, specifically:
the equivalent slender rod is divided into a plurality of micro-segments, when the centrifugal machine rotates, the deformation amount of any one long dr and the micro-segment positioned at the radius r is dl, and the strain value is epsilon.
As an alternative embodiment, in step S500, determining the dynamic radius of the centrifuge according to the sum of the deformations of each micro segment specifically includes the following steps:
s501, obtaining a function curve of the strain value epsilon of the micro-segment and the radius r of the micro-segment through cubic spline interpolation fitting;
s502, integrating the epsilon dr from R to 0 to R to obtain the deformation of the static radius R; the amount of deformation is the dynamic radius Δ R.
Specifically, as shown in fig. 2, the sum of the strain gage 3 farthest from the axis system and the strain of the small segment at the radius R can be regarded as the deformation of the small segment at the radius R, and the sum of the deformations of all the small segments is the deformation of the equivalent elongated rod.
As an alternative embodiment, the distance between two adjacent strain gages 3 is measured and calibrated by a standard gauge block. The smaller the distance between two adjacent strain gauges 3 is, the larger the number of divided micro-segments of the equivalent elongated rod is, and the more accurate the final calculation result is for calculus calculation.
As an alternative embodiment, the measurement accuracy of the dynamic radius of the centrifuge is positively correlated with the number of strain gauges. The more the strain gauges are, the larger the number of the divided micro-segments of the equivalent slender rod is, and the more accurate the final calculation result is for calculus calculation.
As an alternative embodiment, the measurement accuracy of the dynamic radius of the centrifuge is inversely related to the dimension of the strain gauge in the radial direction. The smaller the size of the strain gauge is, the smaller the length of the divided micro-segment of the equivalent elongated rod is, and the more accurate the final calculation result is for calculus calculation.
Fig. 2 is a schematic structural diagram of a precision centrifuge dynamic radius measuring device based on a strain gauge according to an embodiment of the present invention, where the device may include a centrifuge table 1, a shaft system 2, a strain gauge 3, a radius reference surface 4, and a load mounting surface 5;
the centrifugal machine table board 1 is arranged on the shaft system 2, the load mounting surface 5 is positioned at the end part of the centrifugal machine table board 1, and the radius reference surface 4 is the end surface of the load mounting surface 5 close to one side of the shaft system 2;
the plurality of strain gauges 3 are sequentially arranged on the table board 1 of the centrifuge along the radius direction, and one end of the strain gauge 3 farthest from the shaft system 2 coincides with the radius reference surface 4.
It should be clear that the embodiments in this specification are described in a progressive manner, and the same or similar parts in the embodiments are referred to each other, and each embodiment focuses on the differences from the other embodiments. The present invention is not limited to the specific steps and structures described above and shown in the drawings. Also, a detailed description of known process techniques is omitted herein for the sake of brevity.
The above are merely examples of the present application and are not intended to limit the present application. Various modifications and alterations to this application will become apparent to those skilled in the art without departing from the scope of this invention. Any modification, equivalent replacement, improvement or the like made within the spirit and principle of the present application shall be included in the scope of the claims of the present application.
Claims (9)
1. A method for measuring the dynamic radius of a precision centrifuge based on a strain gauge is characterized by comprising the following steps:
mounting a centrifugal machine table board on a shaft system, and determining that the end surface of a load mounting surface on the centrifugal machine table board close to one side of the shaft system is a radius datum plane;
sequentially arranging a plurality of strain gauges on the table board of the centrifuge along the radius direction, wherein one end of a first strain gauge farthest from the shaft system is superposed with the radius reference surface;
when the centrifuge is static, determining that the table top of the centrifuge is an equivalent slender rod with a uniform cross section along the radial direction;
when the centrifuge rotates, dividing the equivalent slender rod into a plurality of micro-segments, and determining the deformation of any micro-segment with the length dr and positioned at the radius r as the strain value of the strain gauge;
and determining the dynamic radius of the centrifuge according to the sum of the deformation of each micro-segment.
2. The method for measuring the dynamic radius of the precision centrifuge based on the strain gauge according to claim 1, wherein the plurality of strain gauges are sequentially arranged on the centrifuge table along a radius direction, and one end of a first strain gauge farthest away from the shaft system coincides with the radius reference plane, specifically:
the strain gauges are sequentially arranged and attached to the table top of the centrifuge at set intervals along the radial direction of the scribed line, and one end of the first strain gauge is overlapped with the radius reference plane.
3. The method for measuring the dynamic radius of the precision centrifuge based on the strain gauge according to claim 1, wherein when the centrifuge is at rest, the centrifuge table is determined to be an equivalent slender rod with a uniform section along the radial direction, specifically:
the centrifuge deck is defined along a radial score line as an equivalent elongated bar of length R that becomes R' in length when the centrifuge is rotated.
4. The method for measuring the dynamic radius of the precision centrifuge based on the strain gauge as claimed in claim 3, wherein the equivalent slender rod is divided into a plurality of tiny segments when the centrifuge rotates, and the deformation of the tiny segment at the radius r and at any length dr is determined as the strain value of the strain gauge, specifically:
and dividing the equivalent slender rod into a plurality of micro-segments, wherein when the centrifuge rotates, the deformation of any one long dr and the micro-segment at the radius r is dl, and the strain value is epsilon.
5. The method for measuring the dynamic radius of the precision centrifuge based on the strain gauge as claimed in claim 4, wherein the step of determining the dynamic radius of the centrifuge according to the sum of the deformation of each micro-segment comprises the following steps:
obtaining a function curve of the strain value epsilon of the micro-segment and the radius r by cubic spline interpolation fitting;
integrating the epsilon dr from R to 0 to R to obtain the deformation amount of the static radius R; the deformation is the dynamic radius Δ R.
6. The method for measuring the dynamic radius of the precision centrifuge based on the strain gauge as claimed in claim 1, wherein the distance between two adjacent strain gauges is measured and calibrated by a standard gauge block.
7. The method for measuring the dynamic radius of the precision centrifuge based on the strain gauge as claimed in claim 1, wherein the measuring precision of the dynamic radius of the centrifuge is positively correlated with the number of the strain gauges.
8. The method of claim 1, wherein the measurement accuracy of the dynamic radius of the centrifuge is inversely related to the dimension of the strain gauge in the radial direction.
9. A precision centrifuge dynamic radius measuring device based on a strain gauge is characterized by comprising a centrifuge table top (1), a shaft system (2), the strain gauge (3), a radius reference surface (4) and a load mounting surface (5);
the centrifugal machine table board (1) is arranged on the shaft system (2), the load mounting surface (5) is positioned at the end part of the centrifugal machine table board (1), and the radius reference surface (4) is an end surface of the load mounting surface (5) close to one side of the shaft system (2);
the plurality of strain gauges (3) are sequentially arranged on the table top (1) of the centrifuge along the radius direction, and one end of the strain gauge farthest from the shaft system (2) is superposed with the radius reference surface (4).
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| Application Number | Priority Date | Filing Date | Title |
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| CN202210649935.7A CN115060153A (en) | 2022-06-10 | 2022-06-10 | Method and device for measuring dynamic radius of precision centrifuge based on strain gauge |
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| Application Number | Priority Date | Filing Date | Title |
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| CN202210649935.7A CN115060153A (en) | 2022-06-10 | 2022-06-10 | Method and device for measuring dynamic radius of precision centrifuge based on strain gauge |
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| CN115060153A true CN115060153A (en) | 2022-09-16 |
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| CN202210649935.7A Pending CN115060153A (en) | 2022-06-10 | 2022-06-10 | Method and device for measuring dynamic radius of precision centrifuge based on strain gauge |
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