The Flywheel Body Dynamics Analysis And The Technology Of Vibration Suppression

With the gradual growth and the development of China’s space industry,there are higher and higher requirements on the stability and the accuracy attitude control of the satellite.Our country has just started on the high precision and high stability in the control technology of the satellite,and the technology is not mature.The flywheel is an important component,which affects the satellite’s high stability and high precision,so the flywheel’s high reliability and long life has a great significance in the attitude control of the satellite.In the launch phase,the flywheel system will suffer a very harsh dynamics environment to produce big flexible deformation of the wheel body,like a powerful vibration,shock and overload acceleration,etc.It is very essential to ensure that the harsh dynamics environment doesn’t cause damage to the flywheel in the process.the elastic vibration of the wheel structure may produce a very large resonant amplification when the satellite is in orbit,so the flexible deformation of the wheel body has a certain impact on the high precision and high stability attitude control of the satellite.This thesis researches on the vibration amplification principle and the vibration characteristics of the wheel body.There are two following measures to reduce the vibration: a.the wheel body structure: based on the optimization methods of the structural dynamic characteristics to reduce the whole vibration of the wheel body;b.the vibration suppression component: the resonance amplification control technology based on the dynamical vibration absorber theory and viscoelastic damping principle to make a vibration control on the resonance amplification of the wheel body.To analyze the conditions that the vibration suppression component reduces the vibration of the wheel body,I respectively made modal tests and vibration transmissibility tests on the wheel body,the wheel body and its vibration suppression component,whose final results illustrated the effectiveness of the flywheel resonance amplification control technology.The thesis is divided into five chapters;the main contents are as follows:Chapter 1: Introduction of the research background and significance,the flywheel system overview,and the induction and conclusion on the research situation of the resonance amplification control technology.Chapter 2: The modal calculation and tests on the wheel body.I established the model of the wheel and bearing assembly components,and made model analysis,harmonic analysis,sine and random vibration analysis to research on the vibration amplification principle and vibration characteristics of the wheel body;On the issue of the larger resonance amplification of the wheel body,I proposed an optimization design method on the geometrical parameters from the aspects of the structure design to reduce the whole vibration of the flywheel.The geometry of the wheel body is made up of the wheel spoke consisting of I-shaped cross section and the wheel flange.The goal of the optimization is to minimize acceleration transmissibility defined as the acceleration ratio of the rim output response to the input of base-excitation.The constraint conditions are the moment of inertia of the wheel body,the geometrical parameters,the strength and stiffness and the mass of the flywheel and,etc.Chapter 3: In order to reduce the whole vibration of the flywheel,the vibration suppression component which is designed is based on the dynamical vibration absorber theory and viscoelastic damping principle to make a vibration control on resonance amplification of the wheel body.I established the dynamical model of the vibration suppression component and made modal parameters analysis.Then I established the dynamical model of the wheel body and its vibration suppression component,made modal parameters analysis and harmonic response parameters analysis.Chapter 4: According to the vibration suppression component,I made modal tests on the modal characteristics of the wheel body,the wheel body and its vibration suppression component at the fixed boundary conditions and made analysis on how the different boundary conditions made an influence on the modal results.I made vibration acceleration transmissibility tests defined as the wheel body relative to the base test and analyzed how the vibration suppression component for the gasket with different materials and different boundary conditions affected the vibration of the wheel body,whose final results verified the effectiveness of the dynamical vibration absorber theory and the viscoelastic damping principle.Chapter 5: Make a summary and generalization on the full summary,main innovations and research prospects.