Dynamic Analysis On The Pointing Behavior Of Antenna With Laminated Compound Material Paraboloidal Reflector

The satellite antenna is an important spacecraft for deep space exploration and communication.Its imaging sharpness and pointing stability are strict required.In a low external resistance space environment,the antenna reflector surface would be excited when it performs large dynamic positioning,pointing and tracking movements.The nonlinear large deformation is extremely difficult to dissipate,and the decrease of the surface accuracy will greatly affect its pointing accuracy and imaging stability.Therefore,it is a great interest to study the dynamic properties of the antenna reflector during dynamic pointing process and to perform vibration control.At this stage,most of the antenna reflectors are laminated composite materials with excellent performance,and their cross-sections are usually parabolic.Therefore,rigid-flexible coupling dynamics modeling considering the non-linear factors for the composite parabolic reflector system will be studied in this paper.This paper focuses on the dynamic modeling of a laminated composite parabolic reflector system that performs large-positioning and pointing motions,and focuses on the influence of nonlinear factors on its system dynamics.Firstly,it expresses its nonlinear geometrical characteristics,and then Reddy's high-order shear deformation theory is employed to derive its nonlinear constitutive relational expression.Further,by using finite element discretization,its kinematics expression is deduced,and Hamilton Variational principle is used to establish the consideration of nonlinear factors.The nonlinear rigid-flexible coupling dynamic equations are derived by considering the effects of laminated composite parabolic reflector undergoing a large-scale positioning motion.According to the presented nonlinear dynamic model and actual conditions,a large-scale motion test bench is built,and laminated/homogeneous composite parabolic reflector model are processed.The dynamic point test analysis is performed on the reflective surface model.Firstly,modal truncation and filtering are performed on the experimental acquisition source data to fit the elastic deformation curve and experimental/theoretical elastic deformation curves of the laminar/homogeneous composite parabolic reflector model.The nonlinear constitutive relation of laminated structures is considered in this modeling.Necessity,the influence of the three nonlinear factors on the imaging/pointing accuracy of the space antenna and their coupling relationship are analyzed and verified in the present modeling.The dynamic example of the laminated composite parabolic reflector model s are analyzed to verify the correctness and rationality of the model in this paper.The laminated parabolic reflector model with different sectional projection functions and different lamination properties is used as the research object,and the nonlinear dynamic model is analyzed for the parabolic projection function and laminar structure parameters of laminated composite parabolic reflectors.The influence of nonlinear geometrical properties and nonlinear constitutive relations is verified on the imaging/pointing accuracy of the space antenna,and further the correctness and adaptability of the dynamic equations are also verified.Finally,the imaging/pointing accuracy of the antenna equipped with laminated composite parabolic reflector in a large dynamic pointing process is concluded by summarizing the effects of the three nonlinear factors and their coupling effects.The theoretical basis and research basis for improving the accuracy of dynamic positioning,pointing and tracking of the paraboloidal antenna reflector are provided.Meanwhile,it can be provided theoretical basis for the dynamic study of the parabolic shells in multi-flexible body frame.