Component motion evaluation method and system

Abstract

The invention relates to the technical field of motion evaluation, in particular to a component motion evaluation method and system. The invention provides a component motion evaluation method which is used for evaluating the motion distance of a rotor of a moving component relative to a stator. Firstly, a radiation source and a detector are arranged on the two opposite sides of a moving part rotor, an auxiliary part is arranged on the rotor so that a plurality of imitation bodies can be vertically placed, and after the radiation source is started, all the imitation bodies form projections on the detector; starting the radiation source, observing the motion law of the phantom projection in the mover motion state, calculating the phantom motion amount, and averaging the phantom motion amount as the mover motion amount; and repeatedly measuring a mover motion amount sequence obtained by measurement under the same target motion amount, and calculating a sequence stability index as a component motion evaluation result. The motion precision evaluation method without a laser interferometer is realized, the harsh requirements of the laser interferometer on the environment and the light path are avoided, the operation is simpler and more convenient, and the cost is lower.

Description

Technical Field

[0001] This invention relates to the field of motion assessment technology, and in particular to a method and system for assessing component motion. Background Technology

[0002] As the core component for generating X-rays, the X-ray source tube has extremely wide and crucial applications in numerous fields such as medicine, industrial non-destructive testing, and materials analysis. In the medical field, whether it's X-ray imaging equipment used for disease diagnosis, such as common X-ray machines and CT scanners, or radiotherapy equipment playing a vital role in tumor treatment, the performance of the X-ray source tube directly affects the accuracy of diagnosis and the effectiveness of treatment. In industrial non-destructive testing, X-rays generated by the X-ray source tube are used to detect internal defects in industrial products, ensuring product quality and safety; its applications cover many industries including aerospace, automotive manufacturing, and pipeline transportation. In the field of materials analysis, the interaction between the X-rays generated by the X-ray source tube and materials is utilized to analyze the composition and structure of materials.

[0003] To facilitate sample measurement, existing technologies utilize moving structures such as turntables to move the sample for CT imaging. This places high demands on the precision of these moving components; insufficient precision will severely impact the final imaging accuracy. Current methods for measuring moving components primarily employ laser interferometers. However, laser interferometers have extremely high environmental and optical path requirements, making precision measurement complex and costly. Therefore, there is an urgent need for a convenient method or system for measuring motion precision. Summary of the Invention

[0004] To overcome the shortcomings of the existing technology, such as the complexity and high cost of using laser interferometers for motion measurement, this invention proposes a component motion evaluation method that can evaluate the motion accuracy of a CT system with high precision in any environment.

[0005] The present invention proposes a component motion evaluation method for evaluating the motion distance of the mover of a moving component relative to the stator. First, a radiation source and a detector are set on opposite sides of the mover of the moving component. An auxiliary part is set on the mover to vertically place multiple phantoms. After the radiation source is activated, each phantom forms a projection on the detector. The X-ray source is activated, and the motion law of the phantom projection is observed under the motion state of the mover. The motion amount of the phantom is calculated, and the average value of the motion amount of the phantom is taken as the motion amount of the mover. The motion amount sequence of the mover obtained under the same target motion amount is measured repeatedly, and the sequence stability index is calculated as the motion evaluation result of the component.

[0006] Preferably, when the mover is in linear motion, the method for calculating the motion error of the phantom is as follows: First, calculate the magnification of the projection of each phantom onto the detector when the mover is in its initial position, as well as the distance of each phantom from the X-ray source; The motion controller is instructed to execute motion commands, and then the magnification of the projection of each phantom onto the detector and the distance of each phantom from the X-ray source are calculated. Using the X-ray source as a reference, the average motion distance of each phantom before and after executing the motion command is calculated as the motion quantity of the mover.

[0007] Preferably, the movement distance of the phantom is the difference between the distance from the X-ray source when the phantom stops moving and the distance from the X-ray source when the phantom is in its initial position; The distance between the phantom and the X-ray source is the ratio of the focal distance from the detector to the X-ray source to the magnification of the phantom's projection onto the detector. The magnification factor is the ratio of the product of the pixel diameter and pixel size of the phantom projection to the actual diameter of the phantom.

[0008] Preferably, when the mover rotates on the surface of the stator, the phantom deviates from the rotation axis of the mover, and the radial deviation of the phantom motion is taken as the motion amount of the phantom; the radial deviation of the phantom motion is: the difference between the distance value of the phantom projection center point before and after the mover motion and the distance value of the phantom center from the rotation axis.

[0009] Preferably, the method for collecting the motion of the mover multiple times under the same target motion is as follows: First, set the target motion and the initial position of the mover, drive the mover to execute motion commands, and calculate the motion of each phantom and the motion of the mover; then reset the mover, repeat the previous step, and collect the motion of the mover multiple times.

[0010] Preferably, the method for collecting the motion quantity of the mover multiple times under the same target motion quantity is as follows: First, set the target motion quantity, reset the mover, drive the mover to execute the motion command, and calculate the motion quantity of each phantom and the motion quantity of the mover; then, take the current position of the mover as the initial position, repeatedly execute the motion command, and collect the motion quantity of the mover; repeat the previous step to obtain multiple motion quantities of the mover.

[0011] Preferably, the phantom adopts a spherical structure.

[0012] Preferably, the stability index of the motion quantity sequence is one or more of the sequence standard deviation, variance and range.

[0013] The present invention proposes a component motion evaluation system, which includes an X-ray source, a detector, a memory, and a processor. The memory stores a computer program, and the processor is connected to the memory. The processor is used to execute the computer program to implement the component motion evaluation method.

[0014] The present invention proposes a storage medium storing a computer program, which, when executed, is used to implement the component motion evaluation method.

[0015] The advantages of this invention are: (1) The component motion evaluation method proposed in this invention utilizes a radiation source and a detector to observe the motion law of the phantom projection, transforming the task of evaluating the motion accuracy of the mover into the task of observing the phantom projection state. This invention combines the projection principle and the motion principle to realize a motion accuracy evaluation method that does not require a laser interferometer, avoiding the stringent requirements of the laser interferometer on the environment and optical path, making it simpler to operate and lower in cost.

[0016] (2) This invention transforms the observation of motion stability of the moving part into the observation of the stability of motion quantity repeatedly acquired by the phantom. By repeatedly measuring and calculating the sequence stability index, it is possible to comprehensively evaluate the repeatability and long-term stability of the moving part, which is crucial for applications such as CT imaging. This invention improves the accuracy and anti-interference ability of the measurement by taking the average of multiple phantom projections as the motion quantity of the moving part.

[0017] (3) This invention combines the principles of motion and projection to clearly define the calculation formula for the motion of the phantom. During linear motion, the motion distance is calculated based on the magnification and focal spot distance. The measurement parameters are quantifiable and easy to obtain, reducing the complexity of image processing, improving calculation efficiency, and ensuring the consistency of results. During rotational motion, the radial deviation of the projection center point of the phantom is calculated, which directly reflects the rotational accuracy of the mover and solves the problem of measuring the accuracy of rotational motion.

[0018] (4) In one evaluation method of the present invention, the motion command is repeatedly executed after reset, which simulates the situation of multiple back-and-forth movements of the component in actual application. This can evaluate the return error and repeatability of the moving component, help to discover systematic errors, and improve the comprehensiveness of the evaluation.

[0019] (5) In another evaluation method of the present invention, the motion command is continuously executed with the current position as the initial position, which avoids frequent resets, is closer to the application scenario of continuous motion (such as CT scan), improves measurement efficiency, and can evaluate the stability drift of moving parts during long-term operation.

[0020] (6) The present invention uses a spherical phantom, and the center point of the sphere is easy to identify in X-ray projection, which simplifies the image processing algorithm. The spherical structure is isotropic and is not affected by direction, so the measurement results are more stable and reliable, and the error caused by the shape of the phantom is reduced.

[0021] (7) This invention provides a variety of statistical indicators such as standard deviation, variance, and range, which users can select as needed to comprehensively evaluate the dispersion and extreme deviation of motion sequences; it enhances the flexibility of the method and can intuitively reflect the precision performance of moving parts. Attached Figure Description

[0022] Figure 1 This is a flowchart of a component motion evaluation method proposed in this invention; Figure 2 This is a schematic diagram of a component motion evaluation system proposed in this invention; Figure 3 This is a projection display of a phantom body; Illustration: 1-X-ray source; 2-stator; 3-mover; 4-phantom; 5-detector; 6-auxiliary part. Detailed Implementation

[0023] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0024] Reference Figure 1 , Figure 2 , Figure 3 The present invention provides a component motion evaluation method for evaluating the motion accuracy of a moving part 3 relative to a stator 2, wherein the motion mode includes translational motion or relative rotation, etc.

[0025] The evaluation system includes: a radiation source 1, phantoms 4, a receiving detector 5, and an auxiliary unit 6. The auxiliary unit 6 is mounted on the mover 3 and is used to place multiple vertically arranged phantoms 4, each phantom being a sphere of equal diameter. The radiation source 1 and the receiving detector are located on opposite sides of the moving area of ​​the mover 3.

[0026] After the X-ray source 1 is turned on, light is projected onto the phantom 4. The phantom 4 forms a projection on the detector 5, and the projection is analyzed to quantitatively evaluate the motion accuracy of the mover 3 relative to the stator 2 in the moving parts.

[0027] In specific operation, first adjust the working voltage, current and other parameters of the X-ray source output. Under the condition of keeping the parameters unchanged, by moving the moving part 3, the projection image of the phantom 4 under specific conditions is obtained. By processing the 2D projection image, the motion accuracy value of the moving part 3 can be calculated quickly and efficiently.

[0028] For ease of explanation, the nth phantom from bottom to top will be abbreviated as sphere n.

[0029] Example 1 When the mover moves in a straight line, the 2D projection image is processed as follows: a linear fitting method (such as the least squares method) is used to automatically find the center of the circle and obtain the coordinate information of the center of the circle; since the projection centers of the X-ray source 1, the phantom 4, and the phantom 4 on the detector 5 are on the same straight line, after obtaining the center of the 2D projection image of each phantom 4, the magnification of the phantom 4 at different positions can be calculated. By calculation, the distance of each phantom 4 from the X-ray source 1 can be obtained, thereby obtaining the actual movement distance of the motion system.

[0030] In this embodiment, let the focal distance from detector 5 to X-ray source 1 be denoted as SDD, and let the actual diameter of the nth phantom 4 from bottom to top be denoted as d. 0n Let the pixel diameter and pixel size of the 2D projection of the nth phantom 4, from bottom to top, be denoted as D. fn and S fn Pixel size is the physical size of a single pixel.

[0031] Let the nth phantom from bottom to top be abbreviated as sphere n; 1≤n≤N; N is the number of phantoms.

[0032] The magnification calculated for ball 1 is M1=D f1 ×S f1 / d 01 ; The magnification calculated by sphere 2 is M2=D f2 ×S f2 / d 02 ; ...... The magnification is calculated to be M for ball n. n =D fn ×S fn / d 0n ; The magnification factor mentioned above represents the magnification factor of the phantom projection relative to the actual size of the phantom.

[0033] Assuming that the moving part 3 moves relative to the stator 2, calculate the distance traveled from station 1 to station 2 on the motion trajectory. The calculation process is as follows: First, at workstation 1 and workstation 2 respectively, calculate the magnification M1, M2, ..., M of each phantom 4. n Let M be the magnification factor of sphere 1, sphere 2, ..., sphere n at workstation 1. 11 M 21 ... M n1 Let M be the magnification factor of sphere 1, sphere 2, ..., sphere n at workstation 2. 12 M 22 ... M n2 ; Calculate the horizontal distance from each phantom to X-ray source 1 at workstation 1: The horizontal distance SAD from sphere 1 to ray source 1 11 =SDD / M 11 ; The horizontal distance SAD from sphere 2 to ray source 1 21 =SDD / M 21 ; ...... The horizontal distance SAD from sphere n to ray source 1 n1 =SDD / M n1 ; Calculate the horizontal distance from each phantom to X-ray source 1 at workstation 2: The horizontal distance SAD from sphere 1 to ray source 1 12 =SDD / M 12 ; The horizontal distance SAD from sphere 2 to ray source 1 22 =SDD / M 22 ; ...... The horizontal distance SAD from sphere n to ray source 1 n2 =SDD / M n2 ; Calculate the movement distance of each phantom from station 1 to station 2: The horizontal distance traveled by ball 1 is D1 = SAD 11 -SAD 12 ; The horizontal distance that ball 2 moves is D2 = SAD 21 -SAD 22 ; ......

[0034] The ball n moves horizontally a distance D n =SAD n1 -SAD n2 ; The moving distance D of the moving part, the rotor 3, relative to the stator 2 is = D n / N; where N is the number of phantoms.

[0035] The moving distance D is the amount of motion of the mover in linear motion. In this embodiment, multiple equally spaced workstations are set up in the direction from workstation 1 to workstation 2. By repeating the above steps, multiple amounts of motion D of the mover under the same target motion can be obtained, forming a sequence {D}. m ,1≤m≤M}, where M is the number of tests.

[0036] Example 2 When the mover 3 rotates horizontally, the phantom 4 needs to deviate from the rotation axis of the mover 3.

[0037] Let the center of the projection of the nth phantom 4 (i.e., sphere n) onto detector 5 be (x) in the initial state. 0n ,y 0n The distance from the axis of rotation of the mover 3 is denoted as R. n R n This is the theoretical radius of the circle along the rotation trajectory of sphere n. In practice, for ease of statistics, the phantom is made of spheres of equal diameter, with their centers distributed along the same vertical line; thus, all R... n All are equal, and the distance R from the straight line containing the center of the phantom to the axis of rotation of the mover is equal to R. n =R.

[0038] After the mover 3 is rotated by an angle c, the center of the projection of sphere n onto detector 5 is (x n,c ,y n,c Then sphere n relative to the center (x) 0n ,y 0n radial deviation δ n,c for:

[0039] In this embodiment, the maximum positional deviation δ corresponding to all phantoms 4 is statistically analyzed. max and average position deviation δ avg : ; ; Where N is the number of phantoms 4.

[0040] In this embodiment, starting from the same or different positions, the radial deviation δ is calculated for each rotation angle c. n,c Let the radial deviation obtained from the m-th rotation angle test be denoted as δ. c,m Construct the sequence {δ c,m ,1≤m≤M}, calculate the standard deviation of the sequence to assess the accuracy of the radial deviation statistics.

[0041] The evaluation methods provided in the two embodiments above are verified by specific experiments.

[0042] Three sets of experiments were conducted, and the simplified system diagram is shown below. Figure 1 As shown: In the first experiment (A), the mover moves linearly along direction u on the surface of the stator. In Experiment B of the second group, the mover moves in a straight line along direction v on the surface of the stator; the directions u and v are not parallel. In the third experiment (C), the mover rotates horizontally on the surface of the stator while the axis of rotation is fixed.

[0043] Each experiment was performed 10 times under the same target amount of exercise, and the statistical results are shown in Table 1.

[0044] Table 1: Statistical analysis of the three experimental groups ; In Table 1, Vpp represents the range of 10 calculations. It can be seen that the ranges for Experiments A and B are 0.37% and 0.34% of the average motion value, respectively, while the range for Experiment C is 5.77e-4 of the calculated mean. Combining the range and variance, it can be seen that this invention exhibits good stability in linear motion detection, and further improvements are possible in rotational motion detection.

[0045] As can be seen from the positioning accuracy in Table 1, the positioning accuracy of this invention is extremely high, which can meet the needs of most application scenarios. This experiment proves the reliability of this invention.

[0046] Of course, those skilled in the art will recognize that the present invention is not limited to the details of the exemplary embodiments described above, but also includes the same or similar structures that can be implemented in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered illustrative and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

[0047] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

[0048] The technologies, shapes, and structures not described in detail in this invention are all known technologies.

Claims

1. A method of component motion assessment, characterized by, The application relates to a method for evaluating the movement distance of a mover of a moving component relative to a stator, wherein a radiation source (1) and a detector (5) are arranged on opposite sides of the mover (3) of the moving component, and a plurality of dummy bodies (4) are arranged on the mover (3) to be perpendicular to each other; the radiation source (1) is started, and the dummy bodies (4) form projections on the detector (5); the movement law of the projections of the dummy bodies (4) is observed under the movement state of the mover (3), the movement amount of the dummy bodies (4) is calculated, and the average of the movement amount of the dummy bodies (4) is taken as the movement amount of the mover; the movement amount sequence of the mover under the same target movement amount is repeatedly measured, and the stability index of the sequence is calculated as the component movement evaluation result. When the mover (3) moves linearly, the method for calculating the movement error of the dummy bodies (4) is as follows:

2. The component motion assessment method of claim 1, wherein, First, the magnification of the projections of the dummy bodies (4) on the detector (5) and the distance of the dummy bodies (4) to the radiation source (1) are calculated when the mover (3) is at the initial position; The mover (3) is driven to execute the movement instruction, and then the magnification of the projections of the dummy bodies (4) on the detector (5) and the distance of the dummy bodies (4) to the radiation source (1) are calculated; The average of the movement distances of the dummy bodies (4) before and after the execution of the movement instruction is taken as the movement amount of the mover. The movement distance of the dummy body (4) is the difference between the distance of the dummy body (4) to the radiation source (1) when the movement of the dummy body (4) stops and the distance of the dummy body (4) to the radiation source (1) when the dummy body (4) is at the initial position; 3. The component motion assessment method of claim 1, wherein, The distance of the dummy body (4) to the radiation source (1) is the ratio of the focal spot distance of the detector (5) to the radiation source (1) to the magnification of the projection of the dummy body (4) on the detector (5); The magnification is the ratio of the product of the pixel diameter of the projection of the dummy body (4) and the pixel size to the real diameter of the dummy body (4). When the mover (3) rotates on the surface of the stator (2), the radial deviation of the movement of the dummy body (4) is taken as the movement amount of the dummy body (4) because the dummy body (4) deviates from the rotation axis of the mover; the radial deviation of the movement of the dummy body (4) is the difference between the distance value of the projection center point of the dummy body (4) before and after the movement of the mover (3) and the distance value of the center of the dummy body (4) to the rotation axis.

4. The component motion assessment method of claim 1, wherein, The method for collecting the movement amount of the mover multiple times under the same target movement amount is as follows: first, the target movement amount and the initial position of the mover are set, the mover is driven to execute the movement instruction, and the movement amount of each dummy body (4) and the movement amount of the mover are calculated; then, the mover is reset, the above step is repeated, and the movement amount of the mover is collected multiple times.

5. The component motion assessment method of claim 1, wherein, The method for collecting the movement amount of the mover multiple times under the same target movement amount is as follows: first, the target movement amount is set, the mover is reset, the mover is driven to execute the movement instruction, and the movement amount of each dummy body (4) and the movement amount of the mover are calculated; then, the current position of the mover is taken as the initial position, the movement instruction is repeatedly executed, and the movement amount of the mover is collected; the above step is repeated to obtain multiple movement amounts of the mover.

6. The component motion assessment method of claim 1, wherein, The dummy body (4) adopts a spherical structure.

7. The component movement assessment method of any one of claims 1 to 6, wherein, The stability index of the sequence of the movement amount of the mover adopts one or more of the sequence standard deviation, the sequence variance and the sequence range.

8. The method of assessing component movement according to any one of claims 1 to 6, wherein, The method comprises a radiation source (1), a detector (5), a memory and a processor, the memory stores a computer program, the processor is connected to the memory, and the processor is used for executing the computer program to realize the component movement evaluation method according to any one of claims 1 to 8.

9. A component motion assessment system characterized by, ​ 10. A storage medium, characterized by A computer program is stored, which, when executed, implements the component movement evaluation method according to any one of claims 1 to 8.

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