Method for testing rotation accuracy of antenna mechanism

Abstract

The application discloses a kind of antenna mechanism rotation accuracy test methods, laser tracking test technology is applied to antenna mechanism rotation accuracy test, by calculating the angular deviation α of all adjacent rotation positions ’ i -α i , finally obtain the root mean square value of all the angular deviations, the root mean square value of all the angular deviations is the rotation accuracy of the measured shaft of the antenna mechanism. The application utilizes the high-precision point measurement function of laser tracker, realizes the rapid test of mechanism rotation accuracy through multi-point acquisition, multi-point fitting and comprehensive analysis, avoids the influence of rotation error of turntable, axis parallel adjustment error, artificial collimation error and prism error in traditional autocollimation measurement method, expands the range of test objects, and greatly improves the test efficiency and reliability of antenna mechanism rotation accuracy.

Description

Technical Field

[0001] This invention relates to the field of antenna measurement technology, and in particular to a method for testing the rotational accuracy of an antenna mechanism. Background Technology

[0002] Satellite antennas utilize pointing, tracking, or scanning mechanisms to change antenna pointing, track moving targets, or perform specific beam scanning. These mechanisms typically require a certain level of mechanical precision. This task originates from the rotational precision testing of various terminal antenna mechanisms, and its main objective is to verify whether the mechanical precision of the mechanism meets the requirements.

[0003] The traditional testing method involves mounting the antenna mechanism on a precision indexing turntable. First, using an electronic theodolite for optical collimation, the orientation of a reference point—a cubic mirror—on the moving parts of the mechanism is determined at its initial position, and the theodolite azimuth reading B1 is recorded. Then, the drive motor of the mechanism is started, causing it to rotate through a predetermined theoretical angle A. Next, the precision turntable reverses angle A, and with the electronic theodolite position unchanged, the reference cubic mirror is collimated again, and the theodolite azimuth reading B2 is recorded. The difference between angles B1 and B2 represents the mechanical accuracy of the mechanism. The advantage of this method is its simple and intuitive testing principle. However, its disadvantages include the need for a precision indexing turntable with an accuracy higher than the mechanical accuracy of the mechanism, and the requirement that the measured rotation axis of the mechanism be pre-adjusted to be parallel to the axis of the precision turntable. Furthermore, for large antenna mechanisms, a general precision turntable may not meet the measurement requirements. Additionally, the manual collimation used to determine the reference orientation inevitably introduces significant testing errors. These disadvantages undoubtedly increase the cost, operational difficulty, and reliability of the measurement results.

[0004] Another method is the photoelectric autocollimator detection method, which requires the use of a precision polyhedral prism. It has high requirements for the measurement environment and the accuracy of the prism. The rotation accuracy angle measurement interval is limited by the prism itself, and it is not possible to perform tests at arbitrary angle intervals. Summary of the Invention

[0005] In order to overcome the above-mentioned technical defects, the purpose of this invention is to provide a method for testing the rotational accuracy of an antenna mechanism using laser tracking testing technology.

[0006] This invention discloses a method for testing the rotational accuracy of an antenna mechanism, comprising the following steps:

[0007] The antenna mechanism under test is stably positioned so that the measured axis of the antenna mechanism does not wobble during rotation; a target ball of a preset size is set on the measured axis, and the target ball is adapted to the laser tracker;

[0008] The laser tracker is positioned at a first preset distance from the target ball to ensure that the laser tracker can see the target ball at any position within the rotation measurement angle range Φ of the measured axis.

[0009] Control the measured axis to rotate to the initial position, and obtain the angle reading γ1 of the measured axis at the initial position; lock the laser tracker to the target ball, and use the laser tracker to measure the three-dimensional coordinate value P1(x1,y1,z1) of the center of the target ball.

[0010] Control the measured axis from its initial position along a first rotation direction at a first preset angle. The axis is rotated at intervals, and the angle reading γ of the measured axis at each rotation position is recorded sequentially. i Simultaneously, the laser tracker sequentially acquires the three-dimensional coordinates P of the center of the target ball at each of the rotation positions. i (x i ,y i ,z i ), until the measured shaft rotates to the stop position; the number of rotation positions i ranges from [1, Φ / +1]; The range of rotation of the measured shaft is between the initial position and the stop position;

[0011] Then, along a second rotation direction opposite to the first rotation direction, at the first preset angle... The axis is rotated at intervals until it returns to the initial position, and the angle reading γ of the axis at each rotation position is recorded sequentially. i Sequentially collect the three-dimensional coordinate values ​​P of the center of the target ball at each of the rotation positions. i (x i ,y i ,z i A total of 2Φ / samples were collected during the rotation in both directions. Data for each of the rotational positions;

[0012] The three-dimensional coordinates of the center of the target ball at all the rotation positions are fitted to a circle, and a corresponding circle center P0(x0, y0, z0) is established. The circle center P0 is then compared with the three-dimensional coordinates P of the target ball at each of the rotation positions. i Establish straight lines L respectively 0i ;

[0013] The angle readings γ of the adjacent rotational positions of the measured shaft are respectively obtained. i γ i+1 To calculate the theoretical rotation angle α for each of the adjacent angular positions. i ; through the straight line L of the adjacent rotational positions0i L 0i1 To calculate its actual rotation angle α ’ i ;

[0014] Calculate the angular deviation α of all adjacent rotational positions. ’ i -α i Finally, the root mean square value of all the angle deviations is obtained, and the root mean square value of all the angle deviations is the rotation accuracy of the measured axis of the antenna mechanism.

[0015] Preferably, the laser tracker acquires the three-dimensional coordinates P of the center of the target sphere. i (x i ,y i ,z i The method includes: setting a spatial position stability threshold for the target ball; when the actual position change of the target ball is less than the spatial position stability threshold, the laser tracker automatically samples the target ball; the range of the spatial position stability threshold is 0-0.01mm.

[0016] Preferably, the laser tracker sequentially acquires the three-dimensional coordinate values ​​P of the center of the target ball at each of the rotation positions. i (x i ,y i ,z i This includes: a single laser tracker, in conjunction with a target prism, measuring the three-dimensional coordinates P of the center of the target sphere. i (x i ,y i ,z i ); where the origin of the coordinate system to which the three-dimensional coordinates belong is the center position of the laser tracker: x i =S i ×cos(H zi ) ×cos(V i );y i =S i ×sin(H zi ) ×cos(V i );z i =S i ×cos(V i ); where S i H is the distance H between the target ball and the laser tracker. zi V is the azimuth angle of the target ball measured by the laser tracker. i The pitch angle of the target ball measured by the laser tracker.

[0017] Preferably, fitting the three-dimensional coordinates of the target ball's center at all the rotation positions to a circle includes: the fitting uses the least squares fitting method, wherein the root mean square value of the deviation of all the three-dimensional coordinates from the circle is minimized.

[0018] Preferably, the distance D between the position of the target ball and the rotation center of the measured axis is not less than 200 mm.

[0019] Preferably, the first preset distance is 1.5m-2m.

[0020] Preferably, the preset size of the target ball is 0.5 inches.

[0021] Preferably, the initial position is one of the extreme positions of the rotation range of the measured shaft.

[0022] Preferably, the first preset angle It is 5 degrees or 10 degrees.

[0023] Preferably, the control of the measured axis from the initial position along the first direction and the second direction at a first preset angle The interval rotation includes: the rotation speed of the measured shaft is not higher than 1° / s.

[0024] Compared with existing technologies, the above technical solution has the following advantages:

[0025] Laser tracking testing technology was applied to the rotational accuracy testing of antenna mechanisms. By utilizing the high-precision point measurement function of the laser tracker, multi-point acquisition and comprehensive analysis were used to achieve rapid testing of the rotational accuracy of the mechanism. This avoided the influence of turntable rotation error, axis parallel adjustment error, manual collimation error and prism error in traditional autocollimation measurement methods, expanded the range of test objects, and significantly improved the testing efficiency and reliability of the test results for the rotational accuracy of antenna mechanisms. Attached Figure Description

[0026] Figure 1 The system upon which the antenna mechanism rotation accuracy testing method provided by this invention is based;

[0027] Figure 2 This is a schematic diagram of the fitted circle provided by the present invention. Detailed Implementation

[0028] The advantages of the present invention will be further illustrated below with reference to the accompanying drawings and specific embodiments.

[0029] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numerals in different drawings denote the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this disclosure. Rather, they are merely examples of apparatuses and methods consistent with some aspects of this disclosure as detailed in the appended claims.

[0030] The terminology used in this disclosure is for the purpose of describing particular embodiments only and is not intended to be limiting of the disclosure. The singular forms "a," "the," and "the" as used in this disclosure and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that the term "and / or" as used herein refers to and includes any and all possible combinations of one or more of the associated listed items.

[0031] It should be understood that although the terms first, second, third, etc., may be used in this disclosure to describe various information, such information should not be limited to these terms. These terms are used only to distinguish information of the same type from one another. For example, without departing from the scope of this disclosure, first information may also be referred to as second information, and similarly, second information may also be referred to as first information. Depending on the context, the word "if" as used herein may be interpreted as "when," "when," or "in response to determination."

[0032] In the description of this invention, it should be understood that the terms "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0033] In the description of this invention, unless otherwise specified and limited, it should be noted that the terms "installation", "connection" and "linking" should be interpreted broadly. For example, they can refer to mechanical or electrical connections, or internal connections between two components. They can be direct connections or indirect connections through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms according to the specific circumstances.

[0034] In the following description, the use of suffixes such as "module," "part," or "unit" to denote elements is solely for the purpose of illustrative purposes and has no specific meaning in itself. Therefore, "module" and "part" may be used interchangeably.

[0035] See appendix Figure 1-2 This invention discloses a method for testing the rotational accuracy of an antenna mechanism, utilizing laser tracking testing technology. The method includes operational steps of the testing system and data analysis steps. A preferred embodiment specifically includes the following steps (where S100-S500 are operational steps of the testing system; S600-S800 are data analysis steps):

[0036] S100: Stabilize and prevent the antenna under test mechanism from shaking during rotation of the tested axis; a 0.5-inch target ball base is fixedly attached to the tested axis of the antenna under test, and the target ball is adsorbed onto the base, thus setting the target ball on the tested axis. This target ball is compatible with the laser tracker and can be captured by the laser tracker; the distance D between the position of the target ball and the rotation center of the tested axis is not less than 200 mm.

[0037] S200. Establish a laser tracking test system: This laser tracking test system includes a single laser tracker, a target prism, and a target sphere base, among other target accessories. The laser tracker is positioned 1.5m-2m away from the target sphere on the antenna mechanism under test, ensuring that the laser tracker can see the target sphere at any position within the rotation measurement angle range Φ of the measured axis. In other words, the laser tracker can track the target sphere at any position within the rotation measurement angle range Φ of the measured axis.

[0038] S300: Control the measured axis to rotate to the initial limit position through the controller of the antenna mechanism under test, and obtain the angle reading γ1 of the measured axis at the initial limit position through the controller; lock the laser tracker to the target ball, and use the laser tracker to measure the three-dimensional coordinate value P1(x1,y1,z1) of the center of the target ball;

[0039] S400, the controller controls the measured axis to move from the initial limit position along the first direction at a first preset angle. The axis is rotated at intervals, and the angle reading γ of the measured axis is recorded sequentially at each rotation position by the controller. i Simultaneously, the three-dimensional coordinates P of the target ball's center at each rotation position are sequentially acquired using a laser tracker. i (x i ,y i ,z i ), until the measured axis rotates to another extreme position, the range of i is [1, Φ / +1]; The angular range between the initial limit position and the other limit position is the rotatable range of the measured shaft;

[0040] S500: After the rotation measurement in one direction (along the first direction) is completed, the rotation is then measured in a second direction opposite to the first direction, at a first preset angle. For the first preset angle of interval Rotate the axis until it returns to its initial limit position, and record the angle reading γ of the axis at each rotation position. i 1. Sequentially collect the three-dimensional coordinates P of the center of the target ball at each rotation position. i (x i ,y i ,z i A total of 2Φ / samples were collected during the rotation in both directions. Data for each rotational position;

[0041] S600, the three-dimensional coordinates of the center of the target ball at all rotational positions (all rotational positions in the first direction and all rotational positions in the second direction) (total 2Φ / The target ball is fitted to a circle, and a corresponding center P0(x0, y0, z0) is established. The three-dimensional coordinates P of the target ball at each rotation position are then compared with the center P0. i Establish straight lines L respectively 0i ;

[0042] S700, angular readings γ from adjacent rotational positions of the measured shaft. i γ i+1 To calculate the theoretical rotation angle α of each adjacent angular position. i = ; A straight line L passing through adjacent rotational positions 0i L 0i1 To calculate its actual rotation angle α ’ i ;

[0043] S800, Calculate the angular deviation α between all adjacent rotational positions. ’ i -α i Finally, the root mean square value of all angular deviations is obtained, and the root mean square value of all angular deviations is the rotational accuracy of the measured axis of the antenna mechanism.

[0044] This invention utilizes high-precision point measurement combined with data analysis to complete the test. The test accuracy depends only on the measurement accuracy of the instrument itself, which greatly improves the test efficiency and reliability. Moreover, this method is applicable to various types of institutions.

[0045] Among them, the three-dimensional coordinates P of the center of the target ball at each rotation position are collected sequentially by a laser tracker. i (x i ,y i ,z i The measurement method for ) is as follows:

[0046] A single laser tracker, in conjunction with target accessories such as a target prism and target base, measures the three-dimensional coordinates P of the target sphere's center based on the principle of polar coordinate measurement. i (x i ,y i ,z i ):x i =S i ×cos(H zi ) ×cos(V i );y i =S i ×sin(H zi ) ×cos(V i );z i =S i ×cos(V i ). Among them, S i H is the distance H between the target ball and the laser tracker. zi V is the azimuth angle of the target ball measured by the laser tracker. i This represents the elevation angle of the target sphere measured by the laser tracker. The origin of the coordinate system to which the three-dimensional coordinates belong is the center of the laser tracker.

[0047] In a preferred embodiment, the laser tracker acquires the three-dimensional coordinates of the target ball's center using a stable automatic measurement method. Specifically, a spatial position stability threshold is set for the target ball. When the actual position change of the target ball is less than the spatial position stability threshold, the laser tracker automatically acquires points on the target ball. The preferred range of the spatial position stability threshold is 0-0.01 mm.

[0048] In a preferred embodiment, when fitting the three-dimensional coordinates of the target ball's center at all rotational positions to a circle, the least squares fitting method can be used, which means minimizing the root mean square value of the deviation of all three-dimensional coordinates from the circle.

[0049] A preferred method is to rotate at a first preset angle each time. The angle can be 5 degrees or 10 degrees. Preferably, the rotation speed is no higher than 1° / s.

[0050] In this embodiment, the target ball is preset to be 0.5 inches. Of course, in other embodiments, other sizes of target balls can also be used. The specific size selection depends on the test requirements.

[0051] In this embodiment, the initial position is one of the extreme positions within the rotation range of the measured shaft, which facilitates the positioning of the initial and stop positions. Of course, in other embodiments, other positions can be used, as long as the angle range between the initial and stop positions is within the rotation range of the measured shaft.

[0052] The laser tracker measurement system is a contact measurement system. During measurement, a spherical prism is used to contact the object being measured. The laser tracker measurement method can be operated by only one person, and it is quick to install and easy to operate. It also has a fast measurement speed of 500-1000 points / second. In addition, the laser automatic tracking function automatically aims at the target, resulting in high measurement accuracy.

[0053] The laser tracking test system is used to measure the rotational accuracy of the mechanism. It does not have the turntable rotation error, axis parallel adjustment error and manual collimation error that exist in traditional measurement methods. It depends entirely on the measurement accuracy of the laser tracker itself. At the same time, it is not limited by the turntable capacity for measuring large mechanisms.

[0054] Under normal circumstances, when testing the rotational accuracy of an antenna mechanism, the spatial position measurement accuracy of the laser tracker can reach 0.015mm. When the distance between the target ball and the axis of the measured axis is 500mm, i.e. the rotation radius is 500mm, the laser tracking test system can measure the rotation angle of the antenna mechanism with an accuracy of 0.0015 degrees, which fully meets the measurement requirements of the rotational accuracy of the antenna mechanism.

[0055] It should be noted that the embodiments of the present invention have better implementability and are not intended to limit the present invention in any way. Any person skilled in the art may use the above-disclosed technical content to change or modify it into equivalent effective embodiments. However, any modifications or equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention shall still fall within the scope of the technical solution of the present invention.

Claims

1. A method for testing the rotation accuracy of an antenna mechanism, characterized in that It includes the following steps: The antenna mechanism under test is stably positioned so that the measured axis of the antenna mechanism does not wobble during rotation; a target ball of a preset size is set on the measured axis, and the target ball is adapted to the laser tracker; The laser tracker is positioned at a first preset distance from the target ball to ensure that the laser tracker can see the target ball at any position within the rotation measurement angle range Φ of the measured axis. Control the measured axis to rotate to the initial position, and obtain the angle reading γ1 of the measured axis at the initial position; lock the laser tracker to the target ball, and use the laser tracker to measure the three-dimensional coordinate value P1(x1,y1,z1) of the center of the target ball. Control the measured axis from its initial position along a first rotation direction at a first preset angle. The axis is rotated at intervals, and the angle reading γ of the measured axis at each rotation position is recorded sequentially. i Simultaneously, the laser tracker sequentially acquires the three-dimensional coordinates P of the center of the target ball at each of the rotation positions. i (x i ,y i ,z i ), until the measured shaft rotates to the stop position; the number of rotation positions i ranges from [1, Φ / +1]; The range of rotation of the measured shaft is between the initial position and the stop position; then rotating in a second rotation direction opposite to the first rotation direction by the first preset angle , and recording the angle reading γ of the measured shaft at each rotation position i , and sequentially collecting the three-dimensional coordinate values P of the center of the target ball at each rotation position i (x i ,y i ,z i ); a total of 2Φ / data of the rotation positions are collected during the rotation in the two rotation directions The three-dimensional coordinates of the center of the target ball at all the rotation positions are fitted to a circle, and a corresponding circle center P0(x0, y0, z0) is established. The circle center P0 is then compared with the three-dimensional coordinates P of the target ball at each of the rotation positions. i Establish straight lines L respectively 0i ; The angle readings γ of the adjacent rotational positions of the measured shaft are respectively obtained. i γ i+1 To calculate the theoretical rotation angle α of each adjacent angular position. i ; through the straight line L of the adjacent rotational positions 0i L 0i1 To calculate its actual rotation angle α ’ i ; calculating the angle deviation a of all adjacent rotation positions ’ i - a i , and finally obtaining the root mean square value of all the angle deviations, which is the rotation accuracy of the measured shaft of the antenna mechanism. Wherein, the laser tracker sequentially collects the three-dimensional coordinate values P of the center of the target ball at each rotation position i (x i ,y i ,z i ) includes: A single laser tracker with target ball prism measures the three-dimensional coordinates P of the center of the target ball i (x i ,y i ,z i ); wherein the origin of the coordinate system to which the three-dimensional coordinates belong is the center position of the laser tracker. x i =S i ×cos(H zi ) ×cos(V i ); y i =S i ×sin(H zi ) ×cos(V i ); from i =S i ×cos(V i ); Where, S i H is the distance H between the target ball and the laser tracker. zi V is the azimuth angle of the target ball measured by the laser tracker. i The pitch angle of the target ball measured by the laser tracker.

2. The method of claim 1, wherein , the laser tracker collects the center three-dimensional coordinate value P of the target ball i (x i ,y i ,z i ) includes: A spatial position stability threshold is set for the target ball. When the actual position change of the target ball is less than the spatial position stability threshold, the laser tracker automatically samples points on the target ball. The range of the spatial position stability threshold is 0-0.01 mm.

3. The method of claim 1, wherein The step of fitting the three-dimensional coordinates of the target ball's center at all the rotational positions into a circle includes: The fitting method employs least squares fitting, where the root mean square value of the deviation of all three-dimensional coordinate values ​​from the circumference is minimized.

4. The method of claim 1, wherein The distance D between the position of the target ball and the rotation center of the measured shaft is not less than 200 mm.

5. The method of claim 1, wherein The first preset distance is 1.5m-2m.

6. The method of claim 1, wherein The preset size of the target ball is 0.5 inches.

7. The method of claim 1, wherein The initial position is one of the extreme positions of the rotation range of the measured shaft.

8. The method of claim 1, wherein , the first preset angle is 5 degrees or 10 degrees.

9. The method of claim 1, wherein , controlling the measured shaft to rotate from an initial position along a first rotation direction, a second rotation direction and a third rotation direction by a first preset angle rotating the interval includes: The rotational speed of the measured shaft is no higher than 1° / s.

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