Adaptable cavity exploration: Bioinspired vibration-propelled PufferFace Robot with a morphable body

Robots with adaptive morphology can improve interactions with their environment, allowing adaptive functions without complicated control strategies. Inspired by a pufferfish, this paper introduces PufferFace Robot (PFR), a vibration-propelled soft robot with an adaptive design for exploring cavities using simple locomotion strategies. PFR is particularly useful for inspecting centimeter-scale pipeline systems with varying diameters and shapes, which pose substantial challenges. Although recent soft robots using smart materials offer advantages, difficulties remain in handling different pipe sizes, navigating transitions, and managing fluid flow. PFR's inflatable soft skin is equipped with flexible spikes that create asymmetrical friction under vibrations, propelling the robot forward without feedback control. Its hollow structure allows fluid flow, while a front-mounted camera enhances inspection capabilities. PFR adapts to various pipeline conditions, navigating cavities 1 to 1.5 times its diameter and critical areas such as 90° elbows, T-connectors, and high-curvature sections. In specific scenarios, PFR can generate a propulsive force 20 to 35 times its weight.