A Modal Test System Suitable for Film Antennas in Vacuum Environment

Abstract

A modal test system suitable for film antennas in a vacuum environment, which consists of a film antenna frame structure, a step excitation device, a DC stabilized power supply and a control circuit, a scanning laser vibrometer, a single-point laser vibrometer, It consists of vacuum environment simulator, data acquisition and analysis system. The film antenna frame structure fixes the film antenna on the outer frame, and introduces different in-plane prestresses into the film antenna by adjusting the force of the bolts. The step excitation device is composed of different types and different numbers of electromagnet exciters, and the adjustable periodic step excitation signal is provided by the DC stabilized power supply and the control circuit, which is used to excite the film antenna to generate the corresponding mode shape. The scanning laser vibrometer and the single-point laser vibrometer are installed outside the vacuum environment simulator, and the emitted laser beam passes through the optical glass observation window on the vacuum environment simulator and finally falls on the film antenna. The data acquisition and analysis system collects and analyzes the return signals of the two laser vibrometers, and finally obtains the modal frequencies and mode shapes of each order of the film antenna.

Description

technical field [0001] The invention relates to a modal test system suitable for thin film antennas in a vacuum environment, which can be used in the modal test of thin film structures in a vacuum environment to obtain the modal frequencies and mode shapes of various orders of thin film structures, and provide products Provide a reliable basis for feature exploration and design improvement. Background technique [0002] Due to the advantages of light weight and small storage volume, the planar film structure has good application prospects in large-scale spacecraft film antennas, solar sails, and sunshades. The modal characteristics of the planar membrane structure directly determine or greatly affect the surface accuracy maintenance and vibration control of the structure, and the correctness of the modal analysis needs to be verified by carrying out ground tests. At present, most of the ground modal tests on planar membrane structures are carried out in the atmospheric envi...

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Problems solved by technology

The acoustic excitation method cannot be used for testing in a vacuum environment. The magnetic excitation method and the MFC patch excitation method need to paste small magnets or MFC piezoelectric patches on the film, which will also introduce a certain additional mass to the film, especially for small films. structure, which will bring errors to the test results

In addition, when using the laser vibrometer to scan and measure the mode of the thin film, foreign researchers have adopted the method of placing the laser vibrometer in a vacuum environment simulator, which puts high requirements on the installation space of the equipment and is not applicable In order to protect the laser vibrometer from the influence of the vacuum environment, it is necessary to make a special protection device, which undoubtedly increases the difficulty of tooling design.

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