Robot is based on leaping lizards
Biologists and engineers at the University of California, Berkeley, are working on leaping robots based on dinosaurs and lizards.
They've been adding a tail to robot designs with the aim of giving them more stability as they jump. And they've found that it's necessary to actively adjust the angle of the tails to the perfect position if they want them to remain upright.
"We showed for the first time that lizards swing their tail up or down to counteract the rotation of their body, keeping them stable," says team leader Robert J Full.
"Inspiration from lizard tails will likely lead to far more agile search-and-rescue robots, as well as ones having greater capability to more rapidly detect chemical, biological or nuclear hazards."
Agile therapod dinosaurs like velociraptors are believed to have used their tails as stabilizers to prevent forward pitch.
"Muscles willing, the dinosaur could be even more effective with a swing of its tail in controlling body attitude than the lizards," says Full.
The team used high-speed videography and motion capture to record how a red-headed African Agama lizard handled leaps from a platform with different degrees of traction, from slippery to easily-gripped.
They found that, on the slippery surface, the lizards used their tails to avoid spinning out of control.
The team then created Tailbot – a toy car equipped with a tail and small gyroscope to sense body position. In itself, they discovered, the tail didn't keep Tailbot stable - but when body position was sensed and fed back to the tail motor, it was able to stabilize its body in midair.
The actively controlled tail effectively redirected the angular momentum of the body into the tail’s swing, in just the same way as in leaping lizards.
Full and his students are now investigating the role of the tail in controlling pitch, roll and yaw while running.
"Robots are not nearly as agile as animals, so anything that can make a robot more stable is an advancement, which is why this work is so exciting," says Full.