Kinematics of an overconstrained 6R linkage with 2-fold rotational symmetry

Abstract

This paper presents an overconstrained 6R linkage which is originated from a metamorphic 8R linkage. The 2-fold rotational symmetry reveals that the overconstrained 6R linkage is a special line-symmetric Bricard loop. The parametric constraints of the overconstrained 6R linkage are investigated in terms of Denavit-Hartenberg convention. This leads to identification of possible variation of parametric constraints for the special line-symmetric Bricard loops. The kinematics of the overconstrained 6R linkage is analyzed and motion parameters of the joint-space are derived. The resultant spherical 4R linkage of the overconstrained 6R linkage is addressed. The results of the joint-space solution are verified with a numerical example.