AAS 98-175

EFFECT OF NONLINEARITY ON THE DYNAMICS OF SPINNING SPACECRAFT APPENDAGES WITH AN OFFSET

A. K. Misra, M. J. Sadigh - McGill University; G. Tyc - Bristol Aerospace Ltd.; V. J. Modi - University of British Columbia

Abstract

The paper considers a spinning system consisting of a central rigid body and a set of appendages, each of which is connected with an offset from the centre of mass of the rigid body. It is observed that when the quadratic terms involving the small elastic generalized coordinates are neglected in the final equations, which is the common practice, the system behaviour for some spin rates depends strongly on the sign of the offset. On the other hand, if the quadratic terms are retained in the equations of motion, the dynamics of the system does not depend on the sign of the offset. The paper explains why neglecting the quadratic elastic terms leads to incorrect stability prediction.

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