SPIRA: Screw Wheel-Based Mobile Robot for Switching Primitives

In this study, we propose a novel movement mechanism for a mobile robot that combines screw-based and general wheel-based mechanisms via switching. As mobile robots developed, their areas of activity gradually expanded to environments including rough terrain such as granular surfaces. Accordingly, the need for a suitable movement mechanism in an environment in which a general rigid surface and a granular surface are combined has increased. To address the limitations of existing movement mechanisms, we develop a switching mechanism that combines a screw-based wheel mechanism that is optimized for rough terrain with general rigid-surface-based mechanisms that exhibit good driving performance. The two individual mechanisms are configured to be used according to the external environment using a switching mechanism. The validity of the proposed mechanism is verified through experiments conducted in a realistic setting using mobile robots. Experimental results show that granular surfaces that cannot be traversed using conventional wheels can be overcome through screw-based wheels through switching mechanisms. In summary, a switching mechanism combining screw-based wheels and normal wheels is presented as a movement mechanism capable of multi-locomotion not only on rough terrain but also on flat land.