Abstract
Parallel wire driven systems have many advantages such as high speed and safety to humans. When the motion of the system is restricted less than 6 D.O.F., mechanical constraints are utilized to fix the unnecessary D.O.F. and the remained freedoms of the system are driven by the parallel wire mechanism. The mechanical constraints should be light for realization of high speed or safety to humans. As the results, the stiffness of the directions made by mechanical constraints decreases and oscillation occurs in many cases. In this paper, we propose a stiffness increase method basing on nonlinear stiffness of the mechanical constraints and the wire drive units. In the proposed method, interference of wire tension with mechanical constraints must be effectively used. In order to obtain an appropriate interference pattern, an algorithm to design wire directions is also proposed. Finally, the effectiveness of the proposed method is demonstrated through several experimental results.
