ECHELON FORM SOLUTION OF DIRECT KINEMATICS FOR THE GENERAL FULLY-PARALLEL SPHERICAL WRIST

This paper presents the echelon form direct position analysis of a cla ss of fully in-parallel actuated mechanisms for the orientation of a r igid body with a fixed point. The mechanisms have a structure which is the most general one for manipulator spherical wrists with three degr ees of freedom and fully-parallel arrangement. The analysis results in a two-equation system in echelon form; the first equation is of 8th o rder and the remaining is linear. As a consequence, when a set of actu ator displacements is given, eight configurations of the mechanism are possible. A numerical example confirms the new theoretical result.