Growing manipulators through feeding material outside-in: Inversion robots

Abstract

Soft eversion robots have demonstrated significant advantages in navigating within confined spaces with minimal friction, making them promising candidates for various intraluminal applications in medical, industrial, and exploratory domains. While these type of growing robots enable frictionless movement within hollow structures, no existing soft robotic actuation mechanism can grow along the outer surface of an environment without generating friction. A robot with these capabilities could open new possibilities, such as endoscopic vein harvesting for coronary artery bypass graft surgery. This paper introduces a novel growing robotic manipulator based on an outside-in material feeding mechanism - the inversion robot. Unlike conventional eversion robots, which expand by feeding material from the inside out, the inversion robot draws material from the outside to the inside, encapsulating its external environment within an inner sleeve to achieve frictionless movement. We present the design, implementation, and experimental validation of this inversion robot, investigating its growth behavior under varying pressure values and with different diameters, its ability to navigate along defined trajectories, and with a tools mounted to its tip. This inversion robot could enable vein dissection while preserving the surrounding fat layer, making it a promising innovation for minimally invasive vascular surgery and beyond.