阅读说明：本技术 一种高精度伞状天线型面评价方法 (High-precision umbrella-shaped antenna profile evaluation method ) 是由 王波 马小飞 李欢笑 师甜 陈国辉 华岳 刘婷婷 张成林 于 2019-08-29 设计创作，主要内容包括：一种高精度伞状天线型面评价方法,属于天线技术领域。本发明方法主要分为三步：对高精度伞状天线型面误差进行分配,将型面误差分为设计及制造误差、测量误差、型面展开重复误差和热变形误差；对天线地面误差进行计算评价,分别计算设计及制造误差、型面测量误差、重复展开误差、热变形误差,得到天线最终地面型面精度；对天线在轨型面进行预示,根据地面试验及有限元仿真,对天线在轨型面进行预测。本发明方法是对天线型面精度进行分配计算,得到满足任务指标的天线型面精度,同时,可以指导天线在地面装配调试及在轨型面预测。型面精度是评价天线的重要指标,利用该方法可以对高精度伞状天线型面进行评价,具有重要的应用价值。(A high-precision umbrella-shaped antenna profile evaluation method belongs to the technical field of antennas. The method of the invention is mainly divided into three steps: distributing the profile errors of the high-precision umbrella-shaped antenna, and dividing the profile errors into design and manufacturing errors, measurement errors, profile unfolding repetition errors and thermal deformation errors; calculating and evaluating the ground errors of the antenna, and respectively calculating design and manufacturing errors, profile measurement errors, repeated expansion errors and thermal deformation errors to obtain the final ground profile accuracy of the antenna; and predicting the on-track profile of the antenna according to ground tests and finite element simulation. The method of the invention is to carry out distribution calculation on the antenna profile precision to obtain the antenna profile precision meeting the task index, and can guide the antenna to be assembled and debugged on the ground and the on-track profile prediction. The profile accuracy is an important index for evaluating the antenna, and the method can be used for evaluating the profile of the high-accuracy umbrella-shaped antenna and has important application value.)

1. A high-precision umbrella-shaped antenna profile evaluation method is characterized by comprising the following steps:

determining evaluation elements of the profile of the umbrella-shaped antenna, respectively calculating evaluation values of the evaluation elements, and testing and calculating on the ground before the umbrella-shaped antenna is transmitted into the track to obtain a ground evaluation value of the profile of the umbrella-shaped antenna;

after the umbrella-shaped antenna operates in the track, predicting the thermal deformation error of the umbrella-shaped antenna on the track profile to obtain the on-track thermal deformation error value of the umbrella-shaped antenna profile;

judging whether the ground evaluation value and the on-orbit thermal deformation error value meet the preset index requirement or not; if both the two are satisfied, the profile of the umbrella-shaped antenna is qualified; otherwise, the profile of the umbrella-shaped antenna is unqualified.

2. The method for evaluating the profile of a high-precision umbrella antenna according to claim 1, wherein: the evaluation factors of the umbrella-shaped antenna profile comprise manufacturing errors, measurement errors, profile unfolding repeated errors and thermal deformation errors.

3. The method for evaluating the profile of a high-precision umbrella antenna according to claim 2, wherein: the method for testing the manufacturing error comprises the following steps:

respectively measuring the mesh surface node data of the umbrella-shaped antenna with the upward opening surface and the downward opening surface to obtain zero-gravity profile data caused by the design and manufacture errors of the antenna ground;

and selecting a plurality of points Z-direction coordinates corresponding to the zero-gravity profile data to be compared with the corresponding theoretical profile point Z-direction coordinates to obtain the design and manufacture errors.

4. A high-precision umbrella antenna profile evaluation method according to claim 3, characterized in that: the manufacturing error is

5. The method for evaluating the profile of a high-precision umbrella antenna according to claim 2, wherein: the measurement error is a fixed value determined from the measurement device.

6. The method for evaluating the profile of a high-precision umbrella antenna according to claim 2, wherein: the test method of the profile unfolding repeated error comprises the following steps:

measuring the coordinates of the profile of the antenna in an unloading state with the opening of the umbrella-shaped antenna facing upwards, and comparing the coordinates with the theoretical coordinates of the profile of the antenna to obtain the error of the measured profile;

and (4) carrying out N times of measurement, and calculating the profile unfolding repeated error according to the N times of measurement profile errors.

7. The method for evaluating the profile of a high-precision umbrella antenna according to claim 6, wherein: the profile deployment repetition error is

8. A method as claimed in claim 2The high-precision umbrella-shaped antenna profile evaluation method is characterized by comprising the following steps of: the thermal deformation error is sigma₄＝δ₂-δ₁(ii) a Wherein, delta₁Is the corresponding profile shape of the antenna under the working condition of normal temperature, delta₂The profile shape at the moment is obtained by measuring the profile of the antenna under the environment of a given temperature.

9. The method for evaluating the profile of a high-precision umbrella antenna according to claim 2, wherein: the ground evaluation value is

10. The method for evaluating the profile of a high-precision umbrella antenna according to claim 1, wherein the method for predicting the thermal deformation error of the umbrella antenna on the track profile comprises the following steps:

establishing a thermal deformation simulation model, and correcting the simulation model according to a thermal deformation test carried out on the ground before the umbrella-shaped antenna is transmitted into the track;

performing temperature field analysis on the operation track of the umbrella-shaped antenna to obtain the on-track full-working-condition temperature field distribution of the umbrella-shaped antenna, and selecting the worst on-track working condition as a simulation temperature field for simulation;

obtaining the antenna on-orbit thermal deformation error sigma under the corresponding temperature field according to the simulation result carried out under the worst on-orbit working condition_zgAs an on-track thermal distortion error value.

Technical Field

The invention relates to a high-precision umbrella-shaped antenna profile evaluation method, and belongs to the technical field of antennas.

Background

Due to the continuous progress of the aerospace science and technology, the aerospace activities such as manned aerospace, deep space exploration and the like put forward higher requirements on the satellite-borne antenna reflector, such as larger caliber, high profile precision, high storage ratio, lighter weight and the like. At present, the application of large-scale satellite-borne mesh antennas is more extensive, the profile precision becomes one of important indexes for evaluating the performance of the antennas, but the profile evaluation method of the mesh antennas only considers the design and manufacturing errors on the ground, and no unified evaluation standard is provided for the prediction of measurement errors, repeated expansion errors, thermal deformation errors and on-track profiles.

According to the characteristics of the mesh antenna, if a complete mesh antenna profile evaluation system can be formed, the method has important significance for evaluating the mesh antenna profile. The method combines the mesh theoretical design and the manufacturing error, simultaneously considers the calculation basis of the measurement error, the repeated expansion error, the ground thermal deformation error and the on-track profile error, and forms a set of complete mesh antenna profile evaluation system, not only considers the mesh profile adjustment value during ground production and manufacturing, but also considers the profile error prediction of the antenna in track, and has important guidance function for judging the mesh antenna profile and the on-track operation.

Disclosure of Invention

The technical problem solved by the invention is as follows: the method is characterized in that a complete mesh antenna profile evaluation system is formed by combining mesh theoretical design and manufacturing errors and considering calculation basis of measurement errors, repeated expansion errors, ground thermal deformation errors and on-track profile errors, and the mesh profile adjustment value during ground production and manufacturing is considered, and the profile error prediction during antenna on-track is also considered.

The technical solution of the invention is as follows: a high-precision umbrella-shaped antenna profile evaluation method comprises the following steps:

determining evaluation elements of the profile of the umbrella-shaped antenna, respectively calculating evaluation values of the evaluation elements, and testing and calculating on the ground before the umbrella-shaped antenna is transmitted into the track to obtain a ground evaluation value of the profile of the umbrella-shaped antenna;

after the umbrella-shaped antenna operates in the track, predicting the thermal deformation error of the umbrella-shaped antenna on the track profile to obtain the on-track thermal deformation error value of the umbrella-shaped antenna profile;

judging whether the ground evaluation value and the on-orbit thermal deformation error value meet the preset index requirement or not; if both the two are satisfied, the profile of the umbrella-shaped antenna is qualified; otherwise, the profile of the umbrella-shaped antenna is unqualified.

Further, the umbrella antenna profile evaluation element includes a manufacturing error, a measurement error, a profile deployment repetition error, and a thermal deformation error.

Further, the method for testing the manufacturing error comprises the following steps:

respectively measuring the mesh surface node data of the umbrella-shaped antenna with the upward opening surface and the downward opening surface to obtain zero-gravity profile data caused by the design and manufacture errors of the antenna ground;

and selecting a plurality of points Z-direction coordinates corresponding to the zero-gravity profile data to be compared with the corresponding theoretical profile point Z-direction coordinates to obtain the design and manufacture errors.

Further, the manufacturing error is

Wherein z is_llIs a theoretical profile point Z-direction coordinate, Z_iThe Z-direction coordinates of the points corresponding to the zero gravity profile data are obtained, and n is the number of the Z-direction coordinates of the selected points.

Further, the measurement error is a fixed value determined from the measurement device.

Further, the test method of the profile unfolding repeated error comprises the following steps:

measuring the coordinates of the profile of the antenna in an unloading state with the opening of the umbrella-shaped antenna facing upwards, and comparing the coordinates with the theoretical coordinates of the profile of the antenna to obtain the error of the measured profile;

and (4) carrying out N times of measurement, and calculating the profile unfolding repeated error according to the N times of measurement profile errors.

Further, the profile deployment repetition error is

Wherein N is the number of measurements, x_iFor measuring profile errors, μ is the average of N measured profile errors.

Further, the thermal deformation error is σ₄＝δ₂-δ₁(ii) a Wherein, delta₁Is the corresponding profile shape of the antenna under the working condition of normal temperature, delta₂The profile shape at the moment is obtained by measuring the profile of the antenna under the environment of a given temperature.

Further, the ground evaluation value isWherein σ₁、σ₂、σ₃And σ₄Manufacturing errors, measurement errors, profile development repetition errors and thermal deformation errors, respectively.

Further, the method for predicting the track profile thermal deformation error of the umbrella antenna comprises the following steps:

establishing a thermal deformation simulation model, and correcting the simulation model according to a thermal deformation test carried out on the ground before the umbrella-shaped antenna is transmitted into the track;

performing temperature field analysis on the operation track of the umbrella-shaped antenna to obtain the on-track full-working-condition temperature field distribution of the umbrella-shaped antenna, and selecting the worst on-track working condition as a simulation temperature field for simulation;

obtaining the antenna on-orbit thermal deformation error sigma under the corresponding temperature field according to the simulation result carried out under the worst on-orbit working condition_zgAs an on-track thermal distortion error value.

Compared with the prior art, the invention has the advantages that:

1. according to the characteristics of the mesh antenna, the invention can realize the evaluation of the profile index of the mesh antenna during ground design, manufacture and debugging;

2. the profile evaluation method provided by the invention can predict the profile of the mesh antenna during in-orbit operation, effectively provides the performance index of the mesh antenna during in-orbit operation, and provides a judgment basis for the long-term in-orbit operation performance of the antenna.

Drawings

FIG. 1 is a schematic flow chart of the process steps of the present invention;

FIG. 2 is a schematic diagram of an on-track profile prediction process according to the present invention;

FIG. 3 is a schematic view of the profile of the antenna of the present invention;

fig. 4 is a schematic view of an antenna mesh according to the present invention;

FIG. 5 is a schematic diagram of the Z-direction error in the method of the present invention.

Detailed Description

A high-precision umbrella-shaped antenna profile evaluation method, as shown in figure 1, comprises the following steps.

Determining evaluation elements of the profile of the umbrella-shaped antenna, respectively calculating evaluation values of the evaluation elements, and testing and calculating on the ground before the umbrella-shaped antenna is transmitted into the track to obtain a ground evaluation value of the profile of the umbrella-shaped antenna.

Comprises the following two steps

1. An allocation is made of the antenna profile error.

The evaluation factors of the umbrella-shaped antenna profile comprise manufacturing errors, measurement errors, profile unfolding repeated errors and thermal deformation errors.

(1) Design and manufacturing tolerances

As shown in fig. 3 and 4, when designing the profile of the antenna, the final profile of the mesh antenna is formed by adjusting and iterating manually during the manufacturing process of the antenna through linear approximation errors and inverse pillow errors under the action of tension, the adjustment point cannot be completely positioned at the theoretical position during the adjustment process, errors caused during the adjustment process are finally introduced into the profile errors of the antenna, the errors are manufacturing errors, the antenna is designed and manufactured on the ground, and the two types of errors are antenna design and manufacturing errors.

(2) Measurement error: the profile measurement of the mesh antenna generally adopts a photogrammetry method, the measurement accuracy of the photogrammetry is related to a plurality of factors such as the size of a measured object, the photogrammetry distance, the photogrammetry baseline, the focal length, the pixel size and the like, and the error caused by the measurement is the measurement error.

(3) Profile deployment repeat error: the discrete error between the profile accuracy of the antenna after each expansion is referred to. The umbrella-shaped antenna is a foldable mesh antenna, the unfolding process of the umbrella-shaped antenna is realized by an unfolding mechanism, and due to the existence of factors such as gaps in the unfolding mechanism, the state of the antenna after each unfolding cannot be completely repeated, certain errors exist among the umbrella-shaped antenna and the unfolding mechanism, and the errors become repeated unfolding errors.

(4) Thermal deformation error: when the antenna works on a track, the antenna needs to experience a space high-low temperature alternating environment, the expansion with heat and the contraction with cold of materials under the high-low temperature environment can cause the size of parts and the tension of a cable net to change, finally, the profile of the antenna changes, and the error is a thermal deformation error.

2. And analyzing and calculating the ground error.

(1) As shown in fig. 5, the antenna operates in a gravity-free environment when in orbit, and the profile accuracy in the gravity-free environment is required to be acquired when performing design and manufacturing error evaluation, while the antenna is performed in a gravity environment during ground manufacturing and testing, and in order to eliminate the influence of gravity, the design and manufacturing profile errors in the gravity-free environment are generally acquired by a method of averaging profile data in two states of face-up and face-down. In FIG. 5, the theoretical surface is the theoretical profile, the real surface is the actual profile, and the point of measurement is the measurement point.

The method for testing the manufacturing error comprises the following steps: respectively measuring the mesh surface node data of the umbrella-shaped antenna with the upward opening surface and the downward opening surface to obtain zero-gravity profile data caused by the design and manufacture errors of the antenna ground; and selecting a plurality of points Z-direction coordinates corresponding to the zero-gravity profile data to be compared with the corresponding theoretical profile point Z-direction coordinates to obtain the design and manufacture errors.

The measured data of the network nodes with the antenna opening facing upwards and the antenna opening facing downwards are averaged to obtain a simulated zero-gravity environment to obtain design and manufacturing errors, and the zero-gravity profile calculation method comprises the following steps:

wherein x is_i、y_i、z_iIs an antenna type surface node, x, after eliminating the influence of gravity_u、x_dRepresenting the antenna profile node coordinates measured mouth-side-up and mouth-side-down, respectively. At the moment, the zero gravity profile data is the profile of the antenna ground design and manufacture error, and the corresponding theoretical profile data is

Wherein f is the theoretical profile focal length. In order to obtain the design and manufacture error, the Z-direction coordinate of the point corresponding to the design and manufacture error is compared with the theoretical profile corresponding point, and the design and manufacture error is obtained and calculated as follows:

wherein z is_llManufacturing profile node x for design_i、y_iCorresponding theoretical profile coordinates.

(2) The evaluation of the repeated errors of the spreading of the molded surface is carried out in the state that the opening surface of the antenna faces upwards and unloads, the number of times N of spreading is generally required to be not less than 5, the coordinates of the molded surface of the antenna in each spreading state are measured, the precision of the molded surface measured in each time is obtained, the mean square error of N groups of data is taken, and the repeated errors of the spreading of the molded surface of the antenna are obtained, wherein the calculation method comprises the:

wherein σ₃In order to repeatedly spread the antennas with a precision,n is the number of measurements, x_iMu is the average value of N profile error measurement results for each profile error measurement.

(3) The test method of the profile unfolding repeated error comprises the following steps: measuring the coordinates of the profile of the antenna in an unloading state with the opening of the umbrella-shaped antenna facing upwards, and comparing the coordinates with the theoretical coordinates of the profile of the antenna to obtain the error of the measured profile; and (4) carrying out N times of measurement, and calculating the profile unfolding repeated error according to the N times of measurement profile errors.

Namely, the antenna thermal deformation test reflects the profile thermal deformation condition under the corresponding working condition by testing the variable quantity of the relative profile under different working conditions, and the specific calculation method is as follows:

under the working condition of normal temperature, the shape delta of the corresponding profile of the antenna₁When the antenna is in the environment of a given temperature, profile measurement is carried out on the antenna to obtain the profile shape delta₂Then the profile error of the antenna in a given temperature environment is calculated as follows:

σ₄＝δ₂-δ₁(5)

(4)σ₂for measuring errors, the value is a certain value when the measuring device determines.

In summary, the antenna ground evaluation indexes are as follows:

predicting the thermal deformation error of the umbrella-shaped antenna on the track profile after the umbrella-shaped antenna operates on the track to obtain the on-track thermal deformation error value of the umbrella-shaped antenna profile;

the on-orbit profile prediction process is shown in fig. 2:

establishing a thermal deformation simulation model, and correcting the simulation model according to a thermal deformation test carried out on the ground before the umbrella-shaped antenna is transmitted into the track;

performing temperature field analysis on the operation track of the umbrella-shaped antenna to obtain the on-track full-working-condition temperature field distribution of the umbrella-shaped antenna, and selecting the worst on-track working condition as a simulation temperature field for simulation;

obtaining a corresponding temperature field according to a simulation result carried out under the worst in-orbit working conditionIn-orbit thermal deformation error sigma of lower antenna_zgAs an on-track thermal distortion error value.

Thirdly, judging whether the ground evaluation value and the on-orbit thermal deformation error value meet the preset index requirement or not; if so, the profile of the umbrella-shaped antenna is qualified; if not, the profile of the umbrella-shaped antenna is unqualified.

The invention can be derived into a shape evaluation method of a spatial expandable mesh antenna and a mesh antenna in a similar form.

An embodiment of the present invention.

Selecting a reticular antenna with the focal length f of 6m and the caliber D of 4.5m, and carrying out ground profile evaluation and on-track profile prediction on 18 antenna ribs (shown in figure 3 in the specification).

According to the actually manufactured antenna, the number of main network adjusting points is 2430 nodes, the adjusting points are measured by adopting a photogrammetry method to obtain main network node data with an upward port surface and a downward port surface, and the node data x of the profile with the design and manufacture error is calculated by the formula_i、y_i、z_iAccording to the design and manufacturing error formula

Calculating to obtain sigma₁0.35; adopting selected measuring equipment, the self measuring error is a fixed value, and the error sigma of the measuring equipment adopted this time is₂0.07; when the ground is designed and manufactured, the ground is required to be folded and unfolded for multiple times, so that the unfolding repeated error is required to be calculated, the measurement is carried out for 6 times, the corresponding molded surface is measured after each time of unfolding, and the unfolding repeated error sigma is obtained according to an unfolding repeated error calculation formula₃0.12; the test temperature of the antenna is high temperature 40 ℃ and low temperature-20 ℃, namely profile calculation is carried out on the antenna under the condition that the temperature difference is 60 ℃, and sigma is obtained according to a thermal deformation error calculation formula₄0.27, therefore, the antenna ground evaluation valueMeets the index requirement of not more than 0.5.

According to the working condition of the temperature of the in-orbit, calculating and simulating to obtain the worst working condition of the temperature of the in-orbit, namely 60 ℃ of high temperature and 30 ℃ of low temperature, according to the working condition of the temperature, modeling and simulating the antenna to obtain the deformation of the antenna under the working condition, wherein the deformation is the deformation under the working condition relative to the normal temperature, and according to the deformation, calculating to obtain the predicted profile sigma of the in-orbit_zgThe on-orbit index requirement not greater than 0.6 is met as 0.53.

The calculated ground profile and the on-rail profile predicted value both meet the index requirement.

Those skilled in the art will appreciate that those matters not described in detail in the present specification are well known in the art.