Abstract: Due to its characteristics of being thin walled and flexible, the dynamics performance parameters of flat solar sails for deployable thin film structures are rather complex. In order to comprehensively and accurately understand the impact of the large flexible solar sail dynamics on the attitude control performance of new hundred kilogram class low Earth orbit satellites, the ANCF (absolute node coordinate formulation) beam model and ANCF membrane elements are used to construct the primary flexible appendages. A dynamic model of large space deployable structures is established based on the predeformation of the beams. With the established dynamic model, complex space environmental disturbances including solar radiation pressure, aerodynamic drag, gravity gradient torque and geomagnetic torque are comprehensively considered. The CMIF (complex modal indicator function) method is employed to identify the modal parameters of the flat solar sail in orbit. Comparison between the identification results and simulation analysis results show that the CMIF method can effectively identify the loworder natural modes of deployable flat solar sails, laying a theoretical foundation for their engineering implementation.

Key words: thin film structured planar solar wing, ANCF, prestress, CMIF