EUROPEAN CONGRESS AND EXHIBITION ON ADVANCED MATERIALS AND PROCESSES - EUROMAT 2021

Soft robots are increasingly used in remote inspection, medicine and other applications with man-machine-interaction as they allow a safe and “natural” interaction between machines and humans. Within the “GrowBot” project, an interdisciplinary consortium of researchers aims for the development of a new generation of plant-inspired growing soft robots, including the construction of innovative robots with thin and flexible backbones. Due to their intrinsically soft materials setup these types of robots often show difficulties in maintaining their intended posture under gravitational and other external loads. Interestingly, the thin-stemmed searcher stems of climbing plants, which often have to span the gap between different supporting host trees face the same problems. Our studies prove that a highly effective solution adopted by such plants is the formation of braid-like structures by intertwining of several individual thin searcher stems. Structural and mechanical analyses of such intertwined searcher braids showed that the flexural stiffness and thereby the potential reach, i.e. the spanable gap, can be markedly increased with significantly reduced material invest compared to a single stem that would be able to span the same distance. We present the structural (increase in axial second moment of area) and mechanical (increase in flexural stiffness / spanable gap) benefits of intertwining for several species of climbing plants, and derive ideas for the development of new plant-inspired robots using inspirations gained from new insights into intertwining mechanics and behavior. Finally we shortly discuss practical applications of the resulting “GrowBots” in various fields of application.