Pentapods With Mobility 2

Abstract

In this paper, we give a full classification of all pentapods with mobility 2, where neither all platform anchor points nor all base anchor points are located on a line. Therefore, this paper solves the famous Borel–Bricard problem for twodimensional motions beside the excluded case of five collinear points with spherical trajectories. But even for this special case, we present three new types as a sideresult. Based on our study of pentapods, we also give a complete list of all nonarchitecturally singular hexapods with twodimensional selfmotions.