Nav: Home

Six-legged robots faster than nature-inspired gait

February 17, 2017

When vertebrates run, their legs exhibit minimal contact with the ground. But insects are different. These six-legged creatures 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. The tripod gait has long inspired engineers who design six-legged robots, but is it necessarily the fastest and most efficient way for bio-inspired robots to move on the ground?

Researchers at EPFL and 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.

The scientists carried out a host of computer simulations, tests on robots and experiments on Drosophila melanogaster - the most commonly studied insect in biology. "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.

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.

Adhesive pads

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. "Our findings support the idea that insects use a tripod gait to most effectively walk on surfaces in three dimensions, and because their legs have adhesive properties. This confirms a long-standing biological hypothesis," said Ramdya. "Ground robots should therefore break free from only using the tripod gait".

Polymer boots

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. "This result shows that, unlike most robots, animals can adapt to find new ways of walking under new circumstances," said Robin Thandiackal, a co-lead author of the study. "There is a natural dialogue between robotics and biology: Many robot designers are inspired by nature and biologists can use robots to better understand the behavior of animal species. We believe that our work represents an important contribution to the study of animal and robotic locomotion."
-end-
Source: Climbing favors the tripod gait over alternative faster insect gaits, Nature Communications

Ecole Polytechnique Fédérale de Lausanne

Related Robots Articles:

Tactile sensor gives robots new capabilities
Eight years ago, Ted Adelson's research group at MIT's Computer Science and Artificial Intelligence Laboratory (CSAIL) unveiled a new sensor technology, called GelSight, that uses physical contact with an object to provide a remarkably detailed 3-D map of its surface.
Researchers question if banning of 'killer robots' actually will stop robots from killing
A University at Buffalo research team has published a paper that implies that the rush to ban and demonize autonomous weapons or 'killer robots' may be a temporary solution, but the actual problem is that society is entering into a situation where systems like these have and will become possible.
Soft robots that mimic human muscles
An EPFL team is developing soft, flexible and reconfigurable robots.
Team of robots learns to work together, without colliding
When you have too many robots together, they get so focused on not colliding with each other that they eventually just stop moving.
Social robots -- programmable by everyone
The startup LuxAI was created following a research project at the Interdisciplinary Centre for Security, Reliability and Trust (SnT) of the University of Luxembourg.
On the path toward molecular robots
Scientists at Hokkaido University have developed light-powered molecular motors that repetitively bend and unbend, bringing us closer to molecular robots.
Gentle strength for robots
A soft actuator using electrically controllable membranes could pave the way for machines that are no danger to humans.
Robots get creative to cut through clutter
Clutter is a special challenge for robots, but new Carnegie Mellon University software is helping robots cope, whether they're beating a path across the moon or grabbing a milk jug from the back of the refrigerator.
Humans can empathize with robots
Toyohashi Tech researchers in cooperation with researchers at Kyoto University have presented the first neurophysiological evidence of humans' ability to empathize with a robot in perceived pain.
Giving robots a more nimble grasp
Engineers at MIT have now hit upon a way to impart more dexterity to simple robotic grippers: using the environment as a helping hand.

Related Robots Reading:

Best Science Podcasts 2019

We have hand picked the best science podcasts for 2019. Sit back and enjoy new science podcasts updated daily from your favorite science news services and scientists.
Now Playing: TED Radio Hour

Setbacks
Failure can feel lonely and final. But can we learn from failure, even reframe it, to feel more like a temporary setback? This hour, TED speakers on changing a crushing defeat into a stepping stone. Guests include entrepreneur Leticia Gasca, psychology professor Alison Ledgerwood, astronomer Phil Plait, former professional athlete Charly Haversat, and UPS training manager Jon Bowers.
Now Playing: Science for the People

#524 The Human Network
What does a network of humans look like and how does it work? How does information spread? How do decisions and opinions spread? What gets distorted as it moves through the network and why? This week we dig into the ins and outs of human networks with Matthew Jackson, Professor of Economics at Stanford University and author of the book "The Human Network: How Your Social Position Determines Your Power, Beliefs, and Behaviours".