Soft Eversion Robots in Application of Minimally Invasive Subsurface Drip Irrigation

Abstract

Currently, the installation of underground irrigation water lines entails a capital and labor intensive process that requires significant disruption of top soil. This means that subsurface drip irrigation (SDI) - a system that despite being over 90% water efficient - is severely underutilized, with only 7% of US farmland deploying SDI systems, and even less on residential land. This project intends to incentivize a transition towards subsurface drip irrigation by providing a less invasive and less expensive method for its installation. We combine a worm-like, soft robot (a vine robot) and pneumatic auger drill to create a robot that can dig and grow underground without the need for soil upheaval. The vine robot can be integrated with a water delivery mechanism to irrigate the area efficiently. The presented research project involved designing and constructing this robot, which successfully dug through 3 feet of soil at a depth of 6 inches with a repeatability of 91.1% over ten trials. Critical features of the digging mechanism were also tested in simulation, providing a means by which future design iterations can take place. With this proof of concept, we lay the groundwork for further development to ensure this low-cost, convenient, and less disruptive approach is utilized to transition towards subsurface drip irrigation, helping use water sustainably. Additionally, from an academic perspective, this is the first demonstration of a vine robot that has navigated underground and lays the groundwork for future work utilizing soft robots in this otherwise unfamiliar territory.