Deployment Mechanism Design and Surface Shape Control of Satellite Antenna Reflector

• Main Author: 段生杏
• Other Authors: 呂宗熙
• Format: Others
• Language: zh-TW
• Published: 2011
• Online Access: http://ndltd.ncl.edu.tw/handle/93947476909775590568

碩士 === 國立交通大學 === 機械工程學系 === 99 === For satellite antenna reflectors, this thesis deals with deployment mechanism design and surface shape control. The proposed deployment mechanism is composed of eight identical parallelograms. When a force is applied to the mechanism, the structure can be gradually extended from a folded form to a fully deployment form. Subject to sunlight and sunshade, the reflector surface generates thermal distortion, which will change the original shape of the antenna reflector and thus degrade microwave transmission. Concerning shape control, this study uses PVDF (Polyvinylidene Fluoride) materials of two thicknesses as sensors and actuators. From experiments, it was found that the ideal positions of sensors and actuators are distributed over the upper and lower surfaces on the reflector. The proposed antenna reflector is made of a circular shape polymer film. As actuators, bimorph beams are used. During thermal distortion, the induced strain will make the sensor generate electrical voltage that enters a proportional-integral(PI) or proportional-integral-derivative(PID) controller. Amplified voltage drives the actuators. The actuators generate counteracting moment to control the shape of the reflector. The result shows that had little effect on the control processes. PI and PID control had almost the same effect on the surface compensation. This is because the oven temperature gradually changes and so does the surface deformation.