Consider the lizard. The ones that climb ought to be both fast and stable in order to avoid predation and find food. A robot designed to mimic their movements has demonstrated the way the rotation of their legs and the speed of which they move up vertical surfaces helps them climb efficiently.
“Most lizards look nearly the same as other lizards,” says Christofer Clemente at the University of sunlight Coast, Australia. To discover why, Clemente and his team built a robot predicated on a lizard’s body to explore its efficiency. It really is about 24 centimetres long, and its own legs and feet were programmed to mimic the gait of climbing lizards.
They pitted the robot against common house geckos ( Hemidactylus frenatus ) and Australian water dragons ( Intellagama lesueurii ), filming them because they completed a vertical climbing test on a carpeted wall. “We thought, imagine if we’re able to make a lizard take on any condition we wanted and see how it climbed,” says Clemente.
The researchers discovered that the best way for both lizards and robots to improve the distance they climbed was to take a Goldilocks approach – not too fast rather than too slow. When the robot climbed while moving at a lot more than 70 % or significantly less than 40 per cent of its maximum speed, it had a 50 per cent potential for falling. In the sweet spot between those speeds, it always stayed on the wall. The lizards climbed at 60 to 80 % of their maximum running speed to keep their grip.
Read more: Gecko Gripper blasts off to help design space-crawling robots
The robot had 100 % success at staying on the wall when its forelimbs were rotated outwards 20 degrees and its hind limbs 100 degrees. In addition, it held fast to the wall when its limbs were rotated inwards at the same angles.
“It works just as well in the event that you rotate inwards or outwards, but we only see outward rotations in nature,” says Clemente.
They also discovered that the robot could climb the furthest when it combined limb movements with a side-to-side spine motion. But the spine could only flex around 50 degrees before the limbs had to go as well to increase stability. Although it may possibly also move by solely rotating its spine, the most effective movement came from large amounts of limb movement and small spine movements.
Looking at the lizards’ phylogenetic trees showed that ancient terrestrial tetrapod linages, such as for example salamanders, exclusively use rotations within their spine to go, but modern climbing lineages move their limbs to increase their reach more. “Evolution was following same gradient as our robot, moving towards this optimum,” says Clemente.
He says this demonstrates some lizards have found the optimum movements for climbing and that this could help build more advanced climbing machines. “If you want to build better robots, the first place we ought to be looking is nature.”
Journal reference: Proceedings of the Royal Society B , DOI: 10.1098/rspb.2020.2576
Join Wild Wild Life, a free of charge monthly newsletter celebrating the diversity and science of animals, plants and Earth’s other weird and wonderful inhabitants
More on these topics:
- animal behaviour