Design of a soft pneumatic robot inspired to plant roots' growth

Roots are extraordinary diggers because they penetrate the soil adding new material on their tip without moving the already grown part, preventing friction from dissipating too much energy and minimising inertial forces during motion. A robot exploiting this principle can assist operations of search and rescue digging in mud or snow to find people in danger. In this work a soft pneumatic robot inspired to roots' growth is presented. The body of the robot consists of a cylindric plastic membrane folded inside out; one extremity is kept fixed to the base, whereas the other one is folded inside itself. When air is blown from the base, the body of the robot is inflated, and its tip is everted increasing its length. Inside the tip a head is mounted, where the mechanism controlling the direction of growth is placed. On the external surface of the membrane some hooks are mounted, and tensioned wires connects them longitudinally while they are folded before being everted. These wires are cut when they pass next to the head allowing the robot to unfold; since series of hooks are distributed radially on the body of the robot, the direction of growth is controlled by selecting which wires are to be cut. On the head of the robot can be mounted an infrared sensor or a video-camera needed for the specific application.