Infinite Torsional Motion Generation of a Spherical Parallel Manipulator with Coaxial Input Axes

One of the distinct features of 3-RRR spherical parallel manipulators with coaxial input axes (coaxial SPM) is the ability to perform infinite torsional motion of the manipulator mobile platform around its normal vectors. This paper presents a novel approach for infinite torsional motion generation of the coaxial SPM based on the author's revised approach for obtaining unique solutions to SPM kinematics and the methodology for numerical computation of the SPM configuration workspace. Numerical results demonstrate the application of the proposed approach for computing infinite torsional motion of a 3D model of a novel coaxial SPM design.