Persistent rigid-body motions on slant helices

This paper reviews the persistent rigid-body motions and examines the geometric conditions of the persistence of some special frame motions on a slant helix. Unlike the Frenet-Serret motion on general helices, the Frenet-Serret motion on slant helices can be persistent. Moreover, even the adapted frame motion on slant helices can be persistent. This paper begins by explaining one-dimensional rigid-body motions and persistent motions. Then, it continues to present persistent frame motions in terms of their instantaneous twists and axode surfaces. Accordingly, the persistence of any frame motions attached to a curve can be characterized by the pitch of an instantaneous twist. This work investigates different frame motions that are persistent, namely frame motions whose instantaneous twist has a constant. pitch. In particular, by expressing the connection between the pitch of Frenet-Serret motion and the pitch of adapted frame motion, it demonstrates that both the Frenet-Serret motion and the adapted frame motion are persistent on slant helices.