Shape-Shifting Robot Trunks
Engineers at Colorado State University have built a robot that bends, collapses and stretches like an elephant's trunk, with no joint anywhere along its body. The machine is called TeCoBot, and it is assembled on the principle of tensegrity, in which stiff rods are held in a web of tensioned cables instead of being locked together at hinges. The work is set out in Nature Machine Intelligence, where Mahmud Hasan Saikot and Sydney Spiegel are named as joint first authors.
Associate Professor Jianguo Zhao, of the university's department of mechanical engineering, calls the machines generalists. Rigid modular robots can dock and rearrange themselves, he said, but they cannot flex, which limits the shapes they can form. A tensegrity body does the opposite, curling around an object to lift it or snaking over rough ground.
A gripping claw at each end does the joining. One robot clamps onto another without magnets, and Zhao said magnets can fail as connection points. And the claws let several of the tubelike bodies lock into a loop, a chain or a branch, whichever shape the job needs.
The team has tested the idea outdoors rather than only on a bench. Saikot, a doctoral student, said the hardest part was finding motors small enough for the range of movement, yet strong enough to stay reliable over long runs. The group tried several configurations and took the robots into the field to see how they crossed natural ground.
Two of the machines have already found each other and docked without help. Everything above that still needs a person at the controls. Zhao wants teams in which most of the decisions sit with the robots.
The intended uses are search and rescue, space exploration, and manufacturing support. A body that can squeeze through a gap and then link up with others would be useful in each of them. But the paper reports demonstrations, and a system in service is still ahead.
Saikot's longer term picture is a team of tens, perhaps hundreds, of the machines travelling to a site and then deploying for a specific purpose. He said the team wants to improve how they work together with minimal human supervision. The group also hopes to make them faster.
The lab's own film shows the hardware at work today. One machine picks a grape from a stem, linked robots pull an object from a stream bed, and four crawl as a single board. All of it is remote controlled apart from the docking.
Other authors on the paper are Sudheera Akalanka Kariyawasam, Andrew Stefka, and Josh Chrisler, all at Colorado State. And the next test is whether that deliberate grip can be handed to the robots themselves. The hardware is modular, so a larger team is a question of more units rather than a new design.
TeCoBot is a tensegrity robot with no rigid joints, so its whole body can flex and grip
Two claws let separate units connect into loops, chains and branches without magnets
Two machines have docked autonomously, but the systems are still steered by people
Search and rescue, space exploration and manufacturing support are the intended uses
