Design of deformable-wheeled robot based on origami structure with shape memory alloy coil spring

Abstract

In this research, a novel concept of a deformable wheel robot using the origami structure is proposed. The word, origami, comes from the traditional Japanese art of paper folding. The unique characteristic of origami that realizes three-dimensional structures from two-dimensional materials have long attracted attention from various fields such as design, education and mathematics [1-6]. Among many researches on engineering applications of origami, some suggest that origami structure can be treated as a kinematic system [7-8]. The research in this paper focus on this characteristic - origami structure is a morphing structure, but it is kinematically designable and can be used as mechanical system. The research present how to deal with three major issues in this topic - pattern design, fabrication and actuation - when the deformable wheel mechanism is realized. The pattern design is key design parameter in determining the function of the mechanism. Desired function can be achieved by appropriate design of pattern. Specially designed magic-ball pattern was developed for achieving desired function. Material and fabrication are also important issue. Depending on the material and the fabrication method, the properties of final origami structure are determined. Therefore, to realize desired functionality of final origami structure, appropriate fabrication method should be selected as well as origami pattern need to be designed properly. In this robot, paper coated with Kapton film and pattern by laser machine was used. Third is actuation design. The wheel structure should be rotate and also has limited space. Shape memory alloy coil spring with slip ring was used for this purpose. Integration of solutions of each issues goes to final product of the deformable wheel robot as in figure 1. It shows adoptability with environment that the diameter of the wheel is 70-mm in normal state but by deforming of the wheel, the robot can pass through the 55-mm slit. The result of the research shows the possibility that origami structure can be a mechanical system.