Leaping Lizards! Tail Helps Robot Keep Balance
Feet like geckos, a tail like a lizard... the robots of the future may be veritable chimeras of traits copied from the natural world.
In the latest in animal-inspired robot design, researchers at the University of California, Berkeley, reported on a small, tailed robot they built that showed how lizardsand possibly sharp-clawed, vertical dinosaurs called Velociraptorsused their tails to maintain their balance while jumping. Leaping lizards provide biological inspiration for the next generation of maneuverable search-and-rescue robots, the researchers wrote in their paper, published ahead of print in Nature on Jan. 4. That is, adding tails to rescue bots may help them hop and jump over rough terrain.
The team of biologists and engineers first studied how red-headed Agama lizards used their tails to adjust the pitch of their bodies as they leapt off of the top of a box to reach a vertical wall with a shelter on top. The boxes had either sandpaper on top for good traction, or were covered with slippery cardstock, which gave the lizards a wobblier trajectory in the air. The scientists found that the lizards swung their tails to maintain the pitch they wanted. A downward tail swing helped lower their nose angles, while upward tail swings compensated for nose dives.
The researchers then built an Agama-size robot car that could sense its pitch with a gyroscope and adjust itself in air with an aluminum tail attached to its back end. Compared to tail-less Agama robots, and to tailed robots that held their tails stiff, the adjustable Tailbot had less rotation in flight.
Turning from the future into the deep past, the scientists studied a model of Velociraptor movement and concluded that the dinosaurs may have used their tails for agile leaping, confirming a decades-old theory.