Error-space-oriented tolerance design for a deployable mechanism with multiple clearances

摘要

This paper presents a geometrical alternative to estimate the accuracy of a deployable mechanism equipped on theSynthetic Aperture Radar (SAR) space satellite. The deployable mechanism is simplified into a planar mechanism,and the error space of the outer panel in its deployed state is modeled concerning multiple revolute joint clearancesand link length tolerances. Compared with the existing methods, the advance of the proposed geometrical approachlies in that it gives expressions of the complete error mobility that the outer panel may have. After deducing theexpressions, the final error space is visualized and evaluated numerically with discrete sampling points. Finally,based on the error space and the computed maximum errors, effects of tolerances on accuracy are studied and theoptimal accuracy design of tolerances is obtained. The result reveals that, for the deployable mechanism discussedin this paper, effects of tolerances on the final accuracy can be eliminated without increasing the manufacturing cost.