Researchers at Ecole Polytechnique Fédérale De Lausanne (EPFL) and University of Lausanne (UNIL) revealed that there is in fact a faster way for robots to locomote on flat ground, provided they don’t have the adhesive pads used by insects to climb walls and ceilings. This suggests designers of insect-inspired robots should make a break with the tripod-gait paradigm and instead consider other possibilities including a new locomotor strategy denoted as the “bipod” gait. The researchers’ findings are published in Nature Communications.
Researchers at EPFL and UNIL have discovered a faster and more efficient gait, never observed in nature, for six-legged robots walking on flat ground. Bio-inspired gaits — less efficient for robots — are used by real insects since they have adhesive pads to walk in three dimensions.
Credit: EPFL/Alain Herzog
To test the various combinations, the researchers used an evolutionary-like algorithm to optimize the walking speed of a simulated insect model based on Drosophila. Step-by-step, this algorithm sifted through many different possible gaits, eliminating the slowest and shortlisting the fastest.
The findings shed new light on problems for biologists and robotics engineers alike. The researchers found that the common insect tripod gait did emerge when they optimized 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.
Researchers at EPFL and UNIL have discovered a faster and more efficient gait, never observed in nature, for six-legged robots walking on flat ground. Bio-inspired gaits — less efficient for robots — are used by real insects since they have adhesive pads to walk in three dimensions. The results provide novel approaches for roboticists and new information to biologists.
The researchers then built a six-legged robot capable of employing either the tripod or bipod gait. The bipod gait was again demonstrated to be faster, corroborating the simulation algorithms’ results.
Finally, the experimenters examined real insects. To see if leg adhesion might also play a role in the walking coordination of real flies, they put polymer drops on the flies’ legs to cover their claws and adhesive pads – as if the flies were wearing boots – and watched what happened. The flies quickly began to use bipod-like leg coordination similar to the one discovered in the simulation.
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