A method and device for measuring dynamic radius of a precision centrifuge based on strain gauges

Abstract

The application relates to a strain-gauge-based dynamic radius measurement method of a precision centrifuge, which comprises the following steps: installing a centrifuge table on a shaft system, determining an end face of a load mounting surface on the centrifuge table as a radius reference face, the end face being close to a side of the shaft system; sequentially arranging a plurality of strain gauges on the centrifuge table along a radius direction, and the end of a first strain gauge farthest from the shaft system coincides with the radius reference face; when the centrifuge is static, determining that the centrifuge table is an equivalent slender rod with an equal cross section along a 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 a length dr and located at a radius r as a strain value of the strain gauge; and determining the dynamic radius of the centrifuge according to the sum of the deformations of each micro segment. The purpose of the strain-gauge-based dynamic radius measurement method and device of the precision centrifuge is to solve the problem that the high requirements of hardware and software for the precision centrifuge dynamic radius measurement based on a micrometer lead to a complex system and high cost.

Description

Technical Field

[0001] This invention relates to the field of precision instrument measurement technology, specifically to a method and apparatus for measuring the dynamic radius of a precision centrifuge based on strain gauges. Background Technology

[0002] High-precision centrifuges are used for the calibration and adjustment of accelerometers, according to the formula a = ω 2 (r0+Δr)cos(α0+Δα)cosβ+gsin(α0+Δα)+gsinγsin(ωt)±2ωω e The dynamic radius Δr has a significant impact on the output angular velocity, therefore, dynamic radius measurement is a key component of high-precision centrifuges.

[0003] Existing measurement methods typically use micrometers to measure the dynamic radius in real time. Based on different measurement principles, micrometers can be installed on either the stator or rotor of a centrifuge. However, stator-type micrometers require accurate acquisition of a specific outer diameter of the centrifuge platform, which places high demands on the sampling frequency and acquisition algorithm. Rotor-type micrometers require the use of a high-precision measuring rod and ring mechanism, which places high demands on the machining, assembly, and inspection of mechanical parts. In summary, precision centrifuge dynamic radius measurement using micrometers has high hardware and software requirements, thus increasing system complexity and cost.

[0004] Therefore, the inventors provide a method and apparatus for measuring the dynamic radius of a precision centrifuge based on strain gauges. Summary of the Invention

[0005] (1) Technical problems to be solved

[0006] This invention provides a method and apparatus for measuring the dynamic radius of a precision centrifuge based on strain gauges, which solves the technical problem that measuring the dynamic radius of a precision centrifuge based on a micrometer requires high hardware and software specifications, resulting in a complex system and high cost.

[0007] (2) Technical solution

[0008] The first aspect of the present invention provides a method for measuring the dynamic radius of a precision centrifuge based on strain gauges, comprising the following steps:

[0009] The centrifuge platform is mounted on the shaft system, and the end face of the load mounting surface on the centrifuge platform that is closer to the shaft system is determined as the radius reference surface;

[0010] Multiple strain gauges are arranged sequentially on the centrifuge platform along the radial direction, with one end of the first strain gauge furthest from the axis coinciding with the radial reference plane.

[0011] When the centrifuge is stationary, the centrifuge platform is determined to be an equivalent slender rod with a uniform cross-section along the radial direction;

[0012] When the centrifuge rotates, the equivalent slender rod is divided into multiple small segments, and the deformation of any small segment of length dr located at radius r is determined to be the strain value of the strain gauge.

[0013] The dynamic radius of the centrifuge is determined based on the sum of the deformations of each tiny segment.

[0014] Furthermore, the step of sequentially arranging multiple strain gauges along the radial direction on the centrifuge platform, with the end of the first strain gauge furthest from the axis coinciding with the radial reference plane, specifically involves:

[0015] Multiple strain gauges are arranged sequentially at predetermined intervals along radial lines on the centrifuge platform, with one end of the first strain gauge coinciding with the radius reference plane.

[0016] Furthermore, when the centrifuge is stationary, determining that the centrifuge platform is an equivalent slender rod with a uniform cross-section along the radial direction specifically involves:

[0017] The centrifuge platform is defined by radial markings as an equivalent slender rod of length R. When the centrifuge rotates, the length of the equivalent slender rod becomes R'.

[0018] Furthermore, when the centrifuge rotates, the equivalent slender rod is divided into multiple small segments, and the deformation of any small segment of length dr located at radius r is determined as the strain value of the strain gauge, specifically as follows:

[0019] The equivalent slender rod is divided into multiple small segments. When the centrifuge rotates, the deformation of any small segment of length dr located at radius r is dl, and the strain value is ε.

[0020] Furthermore, determining the dynamic radius of the centrifuge based on the sum of the deformations of each micro-segment specifically includes the following steps:

[0021] By fitting with cubic spline interpolation, the function curve of the strain value ε of the small segment versus its radius r is obtained;

[0022] Integrating εdr from r=0 to r=R yields the deformation of the static radius R; the deformation is the dynamic radius ΔR.

[0023] Furthermore, the spacing between two adjacent strain gauges is measured and calibrated using standard gauge blocks.

[0024] Furthermore, the measurement accuracy of the dynamic radius of the centrifuge is positively correlated with the number of strain gauges.

[0025] Furthermore, the measurement accuracy of the dynamic radius of the centrifuge is inversely correlated with the radial dimension of the strain gauge.

[0026] A second aspect of the present invention provides a precision centrifuge dynamic radius measuring device based on strain gauges, comprising a centrifuge platform, a shaft system, strain gauges, a radius reference surface, and a load mounting surface;

[0027] The centrifuge platform is mounted on the shaft system, the load mounting surface is located at the end of the centrifuge platform, and the radius reference surface is the end face of the load mounting surface near the shaft system.

[0028] Multiple strain gauges are arranged sequentially along the radial direction on the centrifuge platform, with the end of the strain gauge furthest from the axis coinciding with the radial reference plane.

[0029] (3) Beneficial effects

[0030] In summary, this invention obtains the dynamic radius by measuring the strain values ​​of each strain gauge along the working radius, based on physical modeling and numerical analysis. This method is simple in principle, accurate in measurement, and has low requirements for hardware and software, effectively reducing system complexity and cost. Attached Figure Description

[0031] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the embodiments of the present invention will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0032] Figure 1 This is a schematic flowchart of a precision centrifuge dynamic radius measurement method based on strain gauges provided in an embodiment of the present invention;

[0033] Figure 2 This is an application scenario diagram of a precision centrifuge dynamic radius measurement based on strain gauges provided by an embodiment of the present invention;

[0034] Figure 3 yes Figure 2 A magnified view of a portion of the image.

[0035] In the picture:

[0036] 1-Tabletop; 2-Shaft system; 3-Strain gauge; 4-Radial reference surface; 5-Load mounting surface; 6-Radial scale. Detailed Implementation

[0037] The embodiments of the present invention will be further described in detail below with reference to the accompanying drawings and examples. The following detailed description of the embodiments and the accompanying drawings are used to illustrate the principles of the present invention by way of example, but should not be used to limit the scope of the present invention. That is, the present invention is not limited to the described embodiments, and any modifications, substitutions and improvements to the parts, components and connection methods are covered without departing from the spirit of the present invention.

[0038] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. This application will now be described in detail with reference to the accompanying drawings and embodiments.

[0039] Figure 1 This is a flowchart illustrating a method for measuring the dynamic radius of a precision centrifuge based on strain gauges, provided by an embodiment of the present invention. The method may include the following steps:

[0040] S100. Install the centrifuge platform on the shaft system and determine the end face of the load mounting surface on the centrifuge platform that is closest to the shaft system as the radius reference surface.

[0041] S200. Multiple strain gauges are sequentially placed on the centrifuge table along the radial direction, with one end of the first strain gauge furthest from the axis coinciding with the radial reference plane.

[0042] S300. When the centrifuge is stationary, the centrifuge platform is determined to be an equivalent slender rod with a uniform cross-section along the radial direction.

[0043] S400. When the centrifuge rotates, the equivalent slender rod is divided into multiple small segments. The deformation of any small segment of length dr and located at radius r is determined by the strain value of the strain gauge.

[0044] S500. Determine the dynamic radius of the centrifuge based on the sum of the deformations of each micro-segment.

[0045] In the above embodiment, the centrifuge platform 1 is mounted on the shaft system 2, the load mounting surface 5 is located at the end of the centrifuge platform 1, and the radius reference surface 4 is the end face of the load mounting surface 5 near the shaft system 2. When the centrifuge is stationary, the distance between the radius reference surface 4 and the axis of the shaft system 2 is the static radius R of the centrifuge. When the centrifuge is working, the shaft system 2 rotates, which drives the platform 1 to rotate. The distance between the radius reference surface 4 and the axis of the shaft system 2 changes and becomes R'. The dynamic radius ΔR = R' - R.

[0046] Strain gauges 3 are attached to the centrifuge platform 1, evenly arranged along the radial markings 6, with a total of N gauges. Adjacent strain gauges 3 are spaced h apart, and one end of the first strain gauge 3 coincides with the radial reference plane 4. The strain value ε of each strain gauge 3 is recorded when the centrifuge platform 1 rotates at its rated speed ω. εL represents the radial deformation of each strain gauge 3. Figure 3As shown, since the dimensions L and D of strain gauge 3 are very small compared to the static radius R, they can be ignored. Therefore, the strain value ε is the strain value along the radial line 6 of the radius reference plane 4.

[0047] As an optional implementation, in step S200, multiple strain gauges are sequentially arranged on the centrifuge platform along the radial direction, with one end of the first strain gauge furthest from the axis coinciding with the radial reference plane. Specifically:

[0048] Multiple strain gauges are arranged sequentially at predetermined intervals along radial lines on the centrifuge platform, with one end of the first strain gauge coinciding with the radius reference plane. This design further improves measurement accuracy. Theoretically, when the predetermined interval between two adjacent strain gauges approaches zero, the measurement result infinitely approximates the true value.

[0049] As an optional implementation, in step S300, when the centrifuge is stationary, an equivalent slender rod with a uniform cross-section along the radial direction of the centrifuge platform is determined, specifically as follows:

[0050] The centrifuge platform is defined by radial lines as an equivalent slender rod of length R. When the centrifuge rotates, the length of the equivalent slender rod becomes R'.

[0051] The static radius R of the centrifuge is measured using an inverse algorithm according to the "Precision Centrifuge Calibration Specification for Linear Accelerometers", which will not be elaborated here.

[0052] As an optional implementation, in step S400, when the centrifuge rotates, the equivalent slender rod is divided into multiple small segments, and the deformation of any small segment of length dr located at radius r is determined as the strain value of the strain gauge, specifically:

[0053] The equivalent slender rod is divided into multiple small segments. When the centrifuge rotates, the deformation of any small segment of length dr located at radius r is dl, and the strain value is ε.

[0054] As an optional implementation, in step S500, the dynamic radius of the centrifuge is determined based on the sum of the deformations of each micro-segment, specifically including the following steps:

[0055] S501. By fitting cubic spline interpolation, the function curve of the strain value ε of the small segment versus its radius r is obtained.

[0056] S502. Integrate εdr from r=0 to r=R to obtain the deformation of the static radius R; the deformation is the dynamic radius ΔR.

[0057] Specifically, such as Figure 2As shown, the strain of strain gauge 3, which is furthest from the axis, can be regarded as the strain of a small segment at radius R. The deformation can also be regarded as the deformation of a small segment at radius R. The sum of the deformation of all small segments is the deformation of the equivalent slender rod.

[0058] As an optional implementation, the distance between two adjacent strain gauges 3 is measured and calibrated using standard gauge blocks. The smaller the distance between two adjacent strain gauges 3, the greater the number of micro-segments that can be divided into for the equivalent slender rod, resulting in a more accurate final calculation result for calculus.

[0059] As an alternative implementation, the measurement accuracy of the centrifuge's dynamic radius is positively correlated with the number of strain gauges. Specifically, the more strain gauges there are, the greater the number of tiny segments that divide the equivalent slender rod, resulting in more accurate calculus calculations.

[0060] As an alternative implementation, the measurement accuracy of the centrifuge's dynamic radius is inversely correlated with the radial dimension of the strain gauge. Specifically, the smaller the strain gauge size, the shorter the length of the equivalent slender rod's segments, resulting in a more accurate final calculation for calculus.

[0061] Figure 2 This is a schematic diagram of a precision centrifuge dynamic radius measuring device based on strain gauges provided in an embodiment of the present invention. The device may include a centrifuge platform 1, a shaft system 2, a strain gauge 3, a radius reference surface 4, and a load mounting surface 5.

[0062] The centrifuge platform 1 is mounted on the shaft system 2, the load mounting surface 5 is located at the end of the centrifuge platform 1, and the radius reference surface 4 is the end face of the load mounting surface 5 near the shaft system 2.

[0063] Multiple strain gauges 3 are arranged sequentially along the radial direction on the centrifuge platform 1, and the end of the strain gauge 3 farthest from the shaft system 2 coincides with the radial reference plane 4.

[0064] It should be noted that the various embodiments in this specification are described in a progressive manner, and the same or similar parts between the various embodiments can be referred to mutually. Each embodiment focuses on describing the differences from other embodiments. The present invention is not limited to the specific steps and structures described above and shown in the figures. Furthermore, for the sake of brevity, detailed descriptions of known methods and techniques are omitted here.

[0065] The above are merely embodiments of this application and are not intended to limit the scope of this application. Various modifications and variations can be made to this application by those skilled in the art without departing from the scope of the invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principle of this application should be included within the scope of the claims of this application.

Claims

1. A method for measuring the dynamic radius of a precision centrifuge based on strain gauges, characterized in that, The method includes the following steps: The centrifuge platform is mounted on the shaft system, and the end face of the load mounting surface on the centrifuge platform that is closer to the shaft system is determined as the radius reference surface; Multiple strain gauges are arranged sequentially on the centrifuge platform along the radial direction, with one end of the first strain gauge furthest from the axis coinciding with the radial reference plane. When the centrifuge is stationary, the centrifuge platform is determined to be an equivalent slender rod with a uniform cross-section along the radial direction; When the centrifuge rotates, the equivalent slender rod is divided into multiple small segments, and the deformation of any small segment of length dr located at radius r is determined to be the strain value of the strain gauge. The dynamic radius of the centrifuge is determined based on the sum of the deformations of each tiny segment. When the centrifuge is stationary, the centrifuge platform is defined as an equivalent slender rod with a uniform cross-section along the radial direction, specifically as follows: The centrifuge platform is defined by radial markings as an equivalent slender rod of length R. When the centrifuge rotates, the length of the equivalent slender rod becomes R'. When the centrifuge rotates, the equivalent slender rod is divided into multiple small segments. The deformation of any small segment of length dr located at radius r is determined to be the strain value of the strain gauge. Specifically: The equivalent slender rod is divided into multiple small segments. When the centrifuge rotates, the deformation of any small segment of length dr located at radius r is dl, and the strain value is ε. The determination of the dynamic radius of the centrifuge based on the sum of the deformations of each micro-segment specifically includes the following steps: By fitting with cubic spline interpolation, the function curve of the strain value ε of the small segment versus its radius r is obtained; Integrating εdr from r=0 to r=R yields the deformation of the static radius R; the deformation is the dynamic radius ΔR.

2. The method for measuring the dynamic radius of a precision centrifuge based on strain gauges according to claim 1, characterized in that, The step of sequentially arranging multiple strain gauges along the radial direction on the centrifuge platform, with the end of the first strain gauge furthest from the axis coinciding with the radial reference plane, specifically involves: Multiple strain gauges are arranged sequentially at predetermined intervals along radial lines on the centrifuge platform, with one end of the first strain gauge coinciding with the radius reference plane.

3. The method for measuring the dynamic radius of a precision centrifuge based on strain gauges according to claim 1, characterized in that, The spacing between two adjacent strain gauges is measured and calibrated using standard gauge blocks.

4. The method for measuring the dynamic radius of a precision centrifuge based on strain gauges according to claim 1, characterized in that, The accuracy of the measurement of the dynamic radius of the centrifuge is positively correlated with the number of strain gauges.

5. The method for measuring the dynamic radius of a precision centrifuge based on strain gauges according to claim 1, characterized in that, The measurement accuracy of the dynamic radius of the centrifuge is inversely correlated with the radial dimension of the strain gauge.

6. An apparatus for measuring the dynamic radius of a precision centrifuge based on strain gauges as described in any one of claims 1-5, characterized in that, It includes a centrifuge platform (1), a shaft system (2), strain gauges (3), a radius reference surface (4), and a load mounting surface (5); The centrifuge platform (1) is mounted on the shaft system (2), the load mounting surface (5) is located at the end of the centrifuge platform (1), and the radius reference surface (4) is the end face of the load mounting surface (5) near the shaft system (2); Multiple strain gauges (3) are arranged sequentially on the centrifuge platform (1) along the radial direction, and the end of the strain gauge farthest from the shaft system (2) coincides with the radial reference plane (4).

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