摘要

This paper presents a dynamic modeling approach for flexible spacecraft with multiple solar panels and flexible joints. Firstly, the characteristic equation for the flexible spacecraft is derived in terms of the partial differential equations of motion for the solar panels, the ordinary differential equations of motion for the central rigid body, the matching conditions at the joints, and the boundary conditions. The natural frequencies and global mode shapes of the flexible spacecraft are determined, and orthogonality relations of the global mode shapes are established. Then, the global mode shapes and their orthogonality relations are used to truncate the dynamical equation of the flexible spacecraft to a set of ordinary differential equations with multiple-DOF. The validity of the derived model is verified by comparing the natural frequencies obtained from the characteristic equation with those obtained from FEM. For each global mode shape, a translation index and a set of rotation indexes are introduced to describe the interaction between the elastic deformation of the solar arrays and the displacements of the central rigid body. Based on the truncated dynamic model obtained in this paper, dynamical responses of the flexible spacecraft with flexible joints are worked out numerically for the cases of orbit control and attitude control, respectively. The corresponding results of the flexible spacecraft with rigid joints are given to illustrate the effects of flexible joints on the responses of the system. The results show that the joint flexibility has a significant effect on the dynamical responses of the flexible spacecraft, especially, in the case of very small stiffness of the joints.