Seahorses inspire robotic arm design

U.S. scientists say a sea horse's tail inspired a flexible robotic arm that could have medical, rescue and bomb detection and detonation uses. Engineers at the University of California, San Diego, said the tail of a seahorse, made up of bony, armored plates that slide past each other, can be compressed to about half its size before permanent damage occurs. Researchers reported they focused on the seahorse because they were specifically looking for an animal that was flexible enough to serve as a model for a robotic arm. "The tail is the seahorse's lifeline," because it allows the animal to anchor itself to corals or seaweed and hide from predators, Michael Porter, a doctoral student in materials science, said. "But no one has looked at the seahorse's tail and bones as a source of armor." The researchers took segments from seahorses' tails and compressed them from different angles, discovering they could be compressed by nearly 50 percent without causing damage because the connective tissue between the tail's bony plates and the tail muscles bore most of the load from the displacement. The seahorse's tail is made up of 36 square-like segments, each composed of four L-shaped corner plates that are free to glide or pivot. The researchers said they plan to use 3D printing to create artificial bony plates modeled on those of the seahorse, which would then be equipped with polymers that would act as muscles with the goal of building a robotic arm that would be a unique hybrid between hard and soft robotic devices. "The study of natural materials can lead to the creation of new and unique materials and structures inspired by nature that are stronger, tougher, lighter and more flexible," University of California-San Diego materials science Professor Joanna McKittrick said.