Towards a bio-inspired burrowing robot: Influence of the tip shape for soil vertical penetration.

                                
==Abstract==

This research exploits biomimicry to engineer innovative solutions for soil exploration and tunnelling in complex environments where soil burrowing is the main challenge. Drawing inspiration from the effective burrowing mechanisms of earthworms, we focused on the development of a untethered bio-inspired earthworm- like robot that faithfully replicates the morphology and behavior of Lumbricus terrestris. While prior efforts have primarily explored the horizontal soil burrowing using small diameter probes, in this study we focused on the vertical burrowing capability of a 30 mm diameter robot body. We conducted an experimental parametric analysis of multiple robot’s tip shapes, concentrating on dry sand as the singular soil type. We inserted each tip at a constant speed and monitored the vertical force magnitude depending on the penetration depth. Higher aspect ratios showed better performance, reducing the penetration force compared to low ratios. Experiments showed that asymmetric tips, designed to enhance horizontal locomotion, do not compromise their performance in vertical burrowing. Additionally, we investigated soil fluidization through pressurized air, that effectively reduced shear resistance and facilitated tip penetration by up to 27%. These findings provide valuable insights into the forces requirements for penetrating deeper soil layers, and are essential for accurately design burrowing robots

== Full Paper ==
<pdf>Media:Draft_Sanchez Pinedo_15662105856.pdf</pdf>