Effecting a breakthrough in making insect-inspired robots run faster, Swiss researchers, led by an Indian-origin scientist, have found a new way by which six-legged insects increase their walking speed.
Six-legged insects run fastest using a three-legged, or “tripod” gait where they have three legs on the ground at all times — two on one side of their body and one on the other.
Researchers at University of Lausanne and École Polytechnique Fédérale de Lausanne in Switzerland revealed that there was a faster way for six-legged robots to locomote on flat ground, provided they don’t have the adhesive pads used by insects to climb walls and ceilings.
In the findings, published in Nature Communications, the designers of insect-inspired robots broke away with the tripod-gait paradigm and consider “bipod” gait as other possibility of locomotor strategy.
“We wanted to determine why insects use a tripod gait and identify whether it is, indeed, the fastest way for six-legged animals and robots to walk,” said Pavan Ramdya, co-lead and corresponding author of the study.
The scientists carried out a host of computer simulations, tests on robots and experiments on Drosophila melanogaster — the most commonly studied insect in biology.
They found that the common insect tripod gait did emerge when they optimised their insect model to climb vertical surfaces with adhesion on the tips of its legs.
By contrast, simulations of ground-walking without the adhesiveness of insects’ legs revealed that bipod gaits, where only two legs are on the ground at any given time, are faster and more efficient — although in nature no insects actually walk this way.
“Our findings support the idea that insects use a tripod gait to most effectively walk on surfaces in three dimensions and also because their legs have adhesive properties,” said Ramdya.
The researchers then built a six-legged robot capable of employing either the tripod or bipod gait and found that the bipod gait was faster, corroborating the simulation algorithms’ results.
Finally, the experimenters examined flies and it was found that when their claws and adhesive pads were covered, the flies quickly began to use bipod-like leg coordination similar to the one found in robots.