Stiffness Analysis of a Semi-symmetrical Three-Translation Delta-CU Parallel Robot

Abstract

The Delta-CU parallel mechanism is a semi-symmetrical 3-DOF translational parallel mechanism designed by the author based on the topological structure design theory of POC equation. Compared with the Delta mechanism, the structure is more simple, and the kinematics performance is consistent. The stiffness modeling and characteristics of Delta-CU mechanism are studied in this paper. First, the stiffness model of the limb is established by using the virtual spring method, and the equilibrium equation of the limb is given. Then, the differential mapping from the deflection of the virtual joint to the end-effector is obtained by the Screw theory, and the Cartesian stiffness matrix of the mechanism is obtained by the equilibrium equation; Finally, through the Virtual Work based stiffness index, the Delta-CU mechanism under given parameters is analyzed and compared with the Delta mechanism.