带多充液箱及柔性附件航天器刚液柔控非线性耦合动力学研究

Space missions increasing complexity require modern spacecraft to be equipped with multiple liquid filled containers and large flexible appendages to execute trajectory and attitude maneuvers during which the non-linearly coupled dynamics between rigid body dynamics, liquid sloshing, flexible vibration and control system will be encountered. The mathematical models for the spacecraft dynamics coupled with liquid slosh and flexible appendage vibration will be obtained by using the consistent synthesis methods. The modern nonlinear theories and methods will be employed to carry out the quantitative and qualitative research, and conduct the hierarchical and multiple scale analysis of the coupled dynamics for the spacecraft system composed of the rigid body, liquid fuel and flexible appendage and controller. The stability criteria and principles will be established by analyzing the mechanism of the nonlinear phenomena of the coupled dynamic system. This project is proposed to meet the impendent requirements from space engineering applications such as spacecraft attitude stabilization, orbit and attitude maneuvers, suppression of the liquid sloshing and flexible appendage vibration. The paramount tasks are to design the robust controller such that all closed-loop signals are bounded and the spacecraft attitude asymptotically tracks the desired output, and it is guaranteed that both the liquid sloshing and flexible appendage vibration are suppressed. The innovative methods and theories for the modeling of dynamically coupled rigid-flexible-liquid-control system and the control of the un-actuated nonlinear dynamic system, the computational results and integrated simulation software for the coupled multi-body system will provide the basis for the complex spacecraft system design.

现代大型航天器要完成长时间及复杂的飞行任务需要携带多燃料贮箱及大型柔性附件。航天器在轨道及姿态机动和控制过程中会遇到刚体运动、液体晃动、柔性附件振动及控制系统之间的非线性耦合问题。本项目采用理论分析、数值仿真及物理实验相结合的综合协调方法对带多充液箱及柔性附件航天器耦合系统建立数学模型。应用现代非线性理论和方法对耦合动力学系统开展多层次、多尺度的定性与定量分析。对耦合大系统的稳定性及非线性控制器设计进行研究。探讨非线性现象发生的机理并给出稳定性判据及准则。针对航天器的姿态镇定、轨道及姿态机动、液体晃动及柔性附件振动等问题，设计自适应复合控制器，保证闭环信号有界并使航天器姿态渐近跟踪预期输出、同时抑制液体晃动及柔性附件的振动。在刚液柔控耦合系统的建模方法和理论、欠驱动系统非线性动力学与控制的方法和理论、多体耦合系统集成一体化仿真软件开发等方面取得创新成果并为复杂航天器总体设计提供参考依据。

现代大型航天器要完成长时间及复杂的飞行任务需要携带多燃料贮箱及大型柔性附件。航天器在轨道及姿态机动和控制过程中会遇到刚体运动、液体晃动、柔性附件振动及控制系统之间的非线性耦合问题。. 本项目采用理论分析、数值仿真及物理实验相结合的综合协调方法对带多充液箱及柔性附件航天器耦合系统建立数学模型。应用现代非线性理论和方法对耦合动力学系统开展多层次、多尺度的定性与定量分析。推导航天器中充液圆柱贮箱内任意点的牵连运动方程,根据壁面边界条件给出了贮箱内液体牵连晃动势的表达式;利用第二类边界条件下的傅立叶-贝塞尔级数展开法对低重力环境下的弯曲自由液面处的复杂动力学边界条件进行处理,建立以液体相对晃动势的模态坐标和晃动波高的模态坐标为状态向量的液体耦合晃动力学方程,通过积分分别得到了耦合晃动力和耦合晃动力矩的解析式;运用准坐标系下的拉格朗日方程建立以航天器主刚体姿态坐标和轨道坐标为状态向量的刚体耦合运动动力学方程,进一步联立上述耦合方程得到航天器整体系统的刚-液耦合动力学状态方程;最后,编制出适用于带多充液圆柱贮箱航天器内刚-液耦合动力学计算的模块化计算程序,通过计算实例验证所编程序的准确性的同时,研究了携带多充液箱航天器系统贮箱布局、外激励方式对航天器刚-液耦合系统动力学特性的影响。应用运动脉动球模型和上述的航天器姿态反馈控制器以及欧拉-伯努利梁理论，建立了同时包含液体燃料晃动和柔性附件振动的航天器刚-液-柔-控耦合动力学模型。在此基础上，研究了液体晃动和柔性附件振动对主刚体姿态运动的扰动方式、液体燃料和柔性附件之间的动力学耦合行为，以及动力学耦合效应对低韦伯数环境下液体燃料再定位过程的影响。. 本项目在刚液柔控耦合系统的建模方法和理论、欠驱动系统非线性动力学与控制的方法和理论、多体耦合系统集成一体化仿真软件开发等方面取得了创新成果并为复杂航天器总体设计提供参考依据。