Soft robot concept for autonomous propagation in confined and obstructed environments

This paper describes a soft robot concept which is conceived to propagate autonomously with respect to energy through confined or obstructed environments with a worm-like microactuator array of small size. As introduction, a short review of the various biomechanics of worms is presented that enabled the elaboration of the propagation concept. Discrete movement of the soft robot is achieved by traveling longitudinal deformation waves, so-called peristaltic waves. The movement and the differential anchoring mechanism are bionically inspired. This concept of a soft self-propelled robot is based on an array of fluid filled segments actuated by circumferentially and longitudinally arranged shape memory alloy (SMA) springs. The propagation is dynamically simulated as an array of adjacent fluid-filled hexahedral elements. Viscous interaction of the morphing soft body with its environment resulting in a propulsion force has been theoretically proved with a lubrication model based on thin film theory. Furthermore, a proof of concept of a passive differential anchoring mechanism based on varying properties of soft membranes is presented within this paper.