快速机动大型挠性航天器的动力学建模

建立带附加质量大型挠性航天器大角度快速机动时的动力学模型。在柔性体变形场中计及耦合效应,采用假设模态法和拉格朗日原理建立挠性航天器系统的一阶近似动力学模型。在模型中忽略轴向变形,并用低阶主模态表示横向变形得到控制模型。理论分析和数值仿真表明: 挠性航天器在历经大角度快速机动时会产生动力刚化现象,传统的零次近似动力学模型会产生错误的仿真结果;附加质量对两种模型的系统刚度产生截然相反的作用;低阶简化模型能够较好地反映系统的动力学特性,可用于控制器设计。

Dynamic Modeling of Large Flexible Spacecraft Undergoing Fast Maneuvering

This article presents a dynamic model for a large flexible spacecraft with its end mass undergoing a large angle, high speed maneuvering. With consideration of the second order term of the coupling deformation field, a first order approximate dynamic model (FADM) of the flexible spacecraft system is developed by using the assumed mode method and the Lagrangian principle. Furthermore, a lower order simplified first order approximate dynamic model (SFADM) is derived by deleting the items related to axial deformation. Numerical simulation and theoretical analysis show that: the second order term has a significant effect on the dynamic characteristics of the system which can account for the dynamic stiffening of the spacecraft, while the traditional zero order approximate dynamic model (ZADM) presents invalid simulation results; the end mass has a “stiffening” effect on the flexible system in FADM, but a “softening” effect in ZADM; the SFADM describes the dynamic behavior well and can be used in controller design.