多柔体系统动力学建模中部件模态的选择

在多柔体系统动力学模型中，部件模态坐标的引入是导致模型高阶的主要原因．因此，降阶时主要着眼于减小用以表示部件弹性变形的部件模态数．基于部件约束模态建立多柔体系统动力学方程，通过对典型的柔性航天器系统的动力学研究，分析系统模态和部件模态之间的对应关系，利用模态价值分析准则和内平衡降阶准则进行模型降阶，根据得到的降阶系统的阶数，对部件进行模态选择，减小所选用的柔性部件模态数，建立降阶动力学方程．利用MATLAB进行动力学仿真，结果表明，通过部件模态的选择来建立降阶动力学方程是可行的．

Selection of component modes for multi-flexible system

Model reduction is one of the important issues in the dynamics analysis of the multi-flexible system. The model coordinate of the flexible appendages added to the system is the reason that causes the order of the system too high. Therefore, the most important question of the model reduction is the selection of the component modes. According to the typical flexible spacecraft ,based on the component modes, the equation of the multi-flexible system is established. The relation of the component modes and system modes is studied. The number of the appendage modes is selected through the modal cost analysis and inner balanced method to build the reduction system. The result is showed that the above method to build the reduction system is feasible though MATLAB.