Study on a Variable Stiffness Mechanism Using Wire Spring

Abstract

In this paper, we propose a variable stiffness mechanism using wire springs. We have proposed such kind of mechanism using nonlinear coil springs. We intend to apply it to continuous passive motion (CPM) machine. It can change the spring characteristic continuously. Its disadvantages are need for wide space and powerful motor to change stiffness. And, it is difficult to design such nonlinear spring. To solve these problems, we propose a mechanism with wire springs. It is easy to obtain the wire spring, because it is material of coil spring. We explain how the design and evaluate it in experiments.