Steering mechanism via tail bias effect for soft toroidal robots

Abstract

The development of mobile robots for confined spaces is increasing and soft toroidal robots have shown considerable potential. However, the existing soft toroidal robots cannot move freely because no steering mechanism has been developed and their mobility is limited by the shape of the robot. In this work, a steering mechanism that can steer while maintaining the soft morphological nature of soft toroidal robots is proposed. To achieve this, different material properties were analyzed and validated. Since a soft toroidal robot using nylon fabric exhibits internal material (tail) bias effect under certain conditions, the robot was modeled based on this bistable state. Based on the modeling, a steering mechanism utilizing the tail bias effect was developed, and it was possible to create a curvature that does not occur in conventional soft toroidal robots and a steering with 1-DOF. Since nylon fabric is used not only in the aerospace application but also in many other soft robots, it is expected that the characterization and modeling in this work will be widely applied in these fields.