A team of researchers has successfully built a leech-shaped robot, called “LEeCH,” which can climb vertical walls easily.
The research group is part of Dr Tomoaki Mashimo, an Associate Professor of Department of Mechanical Engineering at the Toyohashi University of Technology, and of Dr Fumiya Iida, a reader in robotics of the Department of Engineering at the University of Cambridge.
LEeCH, which stands for longitudinally extensible continuum-robot inspired by Hirudinea, has a flexible body and is composed of a material utilized for shower hose along with a couple of suction cups. Similar to a leech, the robot is capable of elongating and bending its body without any limitations. The suction cups combined with its flexible body structure enable the robot to effectively ascend a vertical wall and also reach the other side of the wall. The results of the study have been reported in an American scientific journal, Soft Robotics on March 27th, 2019.
Many different potential applications are possible with wall-climbing robots, such as search and rescue operations at disaster sites, and building inspection and maintenance. Although it might be relatively easy to climb vertical walls directly, in reality, it is quite different. The robot may need to steer through obstacles on the wall, for example, steps and transition to walls with varied directions. Reaching the other side of the wall is the hardest task. A robot that has the ability to climb up to the top of the wall has to encounter extreme challenges in navigating the summit over to the other side of the wall.
Taking a cue from land leeches, the researchers were able to develop a new, unique robot. Land leeches are known to be remarkable climbers in nature. They are often found in mountains or forests and can move around difficult walls and terrains utilizing a pair of suction cups provided on either end of their soft extensible bodies. The soft and light bodies of the leeches protect them significantly even if they fall from a great height.
The researchers successfully created a novel motion mechanism by utilizing the tube structure of the shower hose to imitate the beneficial characteristics of leeches, such as flexible, lightweight, and extensible. In general households, the flexible tube having a metal plate with S-shaped profile spirally wound has been utilized. The helical groove on the tube surface engages with a gear. The rotational motion causes the flexible tube to move to and fro. The robot has a body made up of three flexible tubes that are linked in parallel. The body can elongate or bend by regulating the length of every flexible tube fed by the gear.
Upward and downward climbing and horizontal transition on a vertical wall were effectively achieved by the robot. By integrating both these transitions, the robot can move freely on a 2D wall surface. Thanks to its flexible body with a huge deformation, the robot is able to move from one side of a vertical wall and reach to the other side. This is the first achievement in the world in creating a flexible and soft robot that has the potential to move freely on a wall.
I came up with the idea in the bathroom of my house. The shower hose went wild as if it had a life when I inadvertently turned on the faucet at maximum. Then an idea occurred to me that if I could manipulate a hose, I might be able to make a robot with dynamic movement of living creature.
Ayato Kanada, Study Lead Author and Doctoral Programs Student, Department of Mechanical Engineering, Toyohashi University of Technology
Kanada is the person in charge of the development.
Leveraging the shower hose’s hollow structure, the researchers are contemplating the possibility of modifying the tube’s stiffness by introducing fluid inside the cavity. A robot that has a flexible body structure is highly protected against collision and also highly adjustable to the environment. It holds a promising application to labor in proximity to human beings.
The study was supported by the Grant-in-Aid for JSPS Research Fellow (No. 17J04776), the UK’s Engineering and Physical Science Research Council (EPSRC) DTP under Award 1476475 and RG92738, and Mathworks Ltd RG90950 378. Ayato Kanada, the paper’s first author, was supported by the Program for Leading Graduate Schools performed by Japan Society for the Promotion of Science of the Ministry of Education, Culture, Sports, Science and Technology.