A group of researchers led by Dr. Tomoaki Mashino, Associate Prof. of Department of Mechanical Engineering at the Toyohashi University of Technology, and Dr. Fumiya Iida, a reader in robotics of the Department of Engineering at the University of Cambridge, has successfully developed a leech-shaped robot, "LEeCH," which can climb a vertical wall.
LEeCH, Longitudinally Extensible Continuum-robot inspired by Hirudinea, with a flexible body, made of a material used for shower hose, and two suction cups, is capable of elongate and bend its shape without any constraints; just like a leech. Courtesy of its flexible body structure and the suction cups, the robot has successfully climbed a vertical wall and even reached to the other side of the wall. The researchers have published the results of the study in Soft Robotics, an American scientific journal.
There are lots of potential applications for the wall climbing robots, including building inspection and maintenance, and search and rescue tasks at disaster sites. Though climbing straight up vertical walls are relatively easy to accomplish, in reality, the robot may have to navigate over obstacles on the wall such as steps and transition to walls with different directions. The most difficult task is to reach the other side of the wall. A robot capable of climbing up to the top of the wall has to face extreme difficulty in traversing the summit over to the other side.
Inspired by land leeches that are excellent climbers in nature, the team has developed a robot. Usually, the land leeches are found in forests or mountains, and they can move around complex terrain and walls using two suction cups on both ends of bodies and soft extensible bodies. Their bodies are so light and delicate that they are not subject to considerable damage from a fall from height.
The scientists designed a new motion mechanism using a tube structure of show hose to mimic the beneficial properties of leeches, namely, lightweight, flexible, and extensible. The flexible tube with a metal plate with S-shaped profile spirally wound has been used in general households. A gear engages with the helical groove on the surface of the tube. The flexible tube moves back and forth by the rotational motion. The robot has a body composed of three flexible tubes that are connected in parallel. The body can bend or elongate by controlling the length of each flexible tube fed by the gear.
The team is considering the possibility of changing the stiffness of the tube by pouring fluid into the cavity to make the most of the hollow structure of the shower hose. Not only is a robot with a flexible body structure adaptable to the environment, but it is also highly secure against collision. It has potential application to labor in proximity to humans.
