The Design Theory And Method Of Solar Panel Unfolding Mechanism For Space Station

With the development of the space industry,space satellites are expected to complete many complex and arduous space missions.As an important device on satellite,solar cell array can provide necessary electric energy for satellite in orbit.The solar cell array is composed of several solar panels and a number of unfolding mechanisms,and unfolding mechanisms drive the solar panels to expand into a solar cell array.At present,most of the unfolding mechanisms only have the function of expansion,therefore,the locking mechanism to realize the locking of the solar panels is needed.The structure of the unfolding mechanism is complex.Therefore,the research on unfolding mechanism with light mass,small volume,high stiffness and multifunctional has become an important work.As a kind of elastic thin shell member,the tape spring can be automatically expanded by the elastic strain energy gathered during the folded process,and locked by its own stiffness after it is unfolded.Because of special mechanical properties,the tape spring has been widely used in some aerospace deployable structures.In this thesis,the tape spring is applied to the solar panel unfolding mechanism,and the design and analysis of the expansion mechanism are carried out.Based on the present research situation of unfolding mechanism in aerospace field and the application of tape spring,the main contents of this thesis are as follows:Firstly,based on the theory of elastic thin shell and yield theory,the material properties and mechanical properties of tape spring members are studied.The effects of geometric parameters on the forward and reverse bending properties of the tape spring are studied from three aspects including the critical moment,the steady moment and the maximum stress.The effects of geometric parameters on the bending properties of the tape spring are found out successfully.The forward bending and the reverse bending are compared,and the conclusion that the reverse bending performance is obviously better than the forward bending is obtained,which provides an important reference for the design of the unfolding mechanism.Secondly,based on the design princple of quantity and opening direction of tape spring,the design scheme of several unfolding mechanism is obtained.Through the comparative analysis of feasible schemes by finite element method,the best design scheme of simple structure,light weight and energy saving--"face to face" double-tape spring unfolding mechanism is obtained.Thirdly,a torque testing system is designed and built for the "face to face" double-tape spring unfolding mechanism The dynamic measurement of bending moment in the unfolding process of the unfolding mechanism is completed,and the curve of the relationship between bending moment and the unfolding angle is obtained.The experimental results were compared with the finite element analysis results,which proved that the finite element analysis method of the unfolding mechanism mentioned above is correct and effective.Finally,the model of the solar panel is established,and the unfolding process of solar panels driven by the unfolding mechanism is analyzed by using dynamic implicit analysis method.The variation curves of system strain energy and acceleration of the panel with the development time are obtained,and the expansion process of solar panels driven by the unfolding mechanism is verified experimentally.The most dangerous frequency value of the development process is obtained,which laid a foundation for the further design improvement.