Stiffness Analysis of 6-SPS Parallel Manipulator

The analytical stiffness equations of 6-SPS spatial parallel manipulator were deduced based on the Conservative Congruence Transformation (CCT) stiffness matrix. The stiffness mappings of the 6-SPS manipulator were given to show the change and behavior of the stiffness with external forces acted on the manipulator. The results show that the stiffness of the 6-SPS manipulator is configuration dependent, and proportional to the actuating forces and joint stiffness. The stiffness is correlates not only to the magnitude of external forces but also the direction of the external force acted upon.

Stiffness Analysis of 3-RPR Planar Parallel Mechanism to the Stiffness Control

The analytical stiffness equations of the 3-RPR planar parallel mechanism are derived in this paper based on the Conservative Congruence Transformation (CCT) stiffness matrix proposed in [1-3]. Stiffness maps of the 3-RPR mechanism are plotted in order to show the behaviour of the stiffness with and without external forces. The stiffness characteristics of the mechanism are analyzed and discussed in details. Numerical examples show that the stiffness in x and in y are well balanced, while the stiffness in tends to be lower.