Relative centers of motion, implicit bars and dead-center positions for planar mechanisms

摘要

This paper characterizes the dead-center positions of a planar mechanism in terms of implicit bars, that can be described in their turn in terms of relative motion centers. Consequently, a graphical procedure for finding motion centers leads to a geometric description for dead-point positions. We give a survey of existing geometric constructions for motion centers, and we illustrate a new technique that makes use of the "Baracs construction".