93-189
On The Dynamics Of The SFU
V. J. Modi* and A. C. Ng**
Abstract
A relatively general Lagrangian formulation for studying the dy-namics of a large class of spacecraft, characterized by interconnected flexible members forming a tree-type topology, i9 presented. Numerical implementation of the governing equations, which are highly nonlinear, nonautonomous, and coupled, are briefly outlined. Versatility of the formulation is demonstrated through dynamical studies of the Japan Space Flyer Unit (SFU). The deployment of the Solar Array Pedal (SAP) in the SFU shows that the spacecraft remains stable under both symmetric and asymmetric deployments. Advantage of the out-of-plane deployment is also illustrated. The retrieval of the SAP is found to be a difficult task. Only the out-of-plane symmetric retrieval is found to be stable; the inplane retrieval induces unsatisfactory librational motion. For the asymmetric retrieval, the spacecraft response is unstable and an active control would be required.
*Professor, Department of Mechanical Engineering, The University of British Columbia, 2324 Main Mall, Vancouver, B.C., Canada V6T 1Z4. Fellow AAS; Fellow AIAA.
**Graduate Research Assistant, Department of Mechanical Engineering, The University of British Columbia.Presently, Research Scientist. Space Systems Directorate, Canadian Space Agency, Suite 2160, 600 de la Gauchetiere West, Montreal, Quebec. Canada H3B 4X7.