3D Steering and Localization in Pipes and Burrows using an Externally Steered Soft Growing Robot

TL;DR

This paper presents a novel externally steered soft vine robot capable of navigating complex 3D pipe and burrow environments, with real-time localization and enhanced maneuverability in confined, GPS-denied spaces.

Contribution

Introduction of a simple, externally steerable vine robot design that actively navigates 3D environments and localizes in GPS-denied spaces, improving maneuverability in complex confined environments.

Findings

Successfully navigates pipe networks with radii as small as 2.5 cm

Achieves a maximum steerable angle of 51.7 degrees

Demonstrates real-time 3D localization in natural burrows

Abstract

Navigation and inspection in confined environments, such as tunnels and pipes, pose significant challenges for existing robots due to limitations in maneuverability and adaptability to varying geometries. Vine robots, which are soft growing continuum robots that extend their length through soft material eversion at their tip, offer unique advantages due to their ability to navigate tight spaces, adapt to complex paths, and minimize friction. However, existing vine robot designs struggle with navigation in manmade and natural passageways, with branches and sharp 3D turns. In this letter, we introduce a steerable vine robot specifically designed for pipe and burrow environments. The robot features a simple tubular body and an external tip mount that steers the vine robot in three degrees of freedom by changing the growth direction and, when necessary, bracing against the wall of the pipe or burrow. Our external tip steering approach enables: (1) active branch selection in 3D space with a maximum steerable angle of 51.7{\deg}, (2) navigation of pipe networks with radii as small as 2.5 cm, (3) a compliant tip enabling navigation of sharp turns, and (4) real-time 3D localization in GPS-denied environments using tip-mounted sensors and continuum body odometry. We describe the forward kinematics, characterize steerability, and demonstrate the system in a 3D pipe system as well as a natural animal burrow.