Soft, pneumatic robotic prototypes that move through obstacles toward a designated goal and grow into a free-standing structure have been engineered at Stanford University. This robot could serve a range of purposes, particularly in the realms of search and rescue and medical devices.
Navigation through growth instead of locomotion is found in fungal hyphae, developing neurons and trailing plants, and is characterized by extension from the tip of the body. The researchers sought to mimic this property by using a tube of soft material folded inside itself, like an inside-out sock. Growth occurs in one direction when the material at the front of the tube everts, as the tube becomes right-side-out. The material used in the protytypes was a thin, cheap plastic and the robot body everted when pressurized air was pumped into the stationary end. In other versions, fluid could replace the pressurized air.
Movement of the tip occurs without movement of the body. The robotic body lengthens from the tip even if the 
The vinebot is a tube of soft material that grows in one direction. (Image credit: L.A. Cicero)remainder is stuck between rocks or hampered by other environmental barriers.
During tests, the robot grew through an obstacle course and traveled over flypaper, sticky glue and nails and up an ice wall to deliver a sensor, which could potentially sense carbon dioxide produced by trapped survivors. It successfully completed this course even though it was punctured by the nails because the area damaged didn’t continue to move and, as a result, self-sealed by staying on top of the nail.
The robot also lifted a 100-kilogram crate, grew under a door gap that was 10 percent of its diameter and spiraled on itself to form a free-standing structure that then sent out a radio signal. The robot also maneuvered through the space above a dropped ceiling, which showed how it was able to navigate unknown obstacles as a device like this might have to do in walls, under roads or inside pipes. A new method for routing wires in tight spaces was demonstrated as it pulled a cable through its body while growing above the dropped ceiling.
