Calculating possible local displacement of curve objects using improved screw theory

Various methods to recognize assembly tasks using possible local displacement of objects have been proposed. To calculate this displacement, the screw theory is employed. It is equivalent to the first order Taylor expansion of the displacement. However, such methods can treat polyhedral objects only. Because the screw theory cannot treat curvature information of objects. In this paper, we propose a method to calculate possible local displacement of curve objects using improved screw theory, which is equivalent to the second order Taylor expansion of the displacement, and verify the validity of the proposed method.