Beyond biomimicry: Scientists find better-than-nature run style for six-legged robots

Researchers have found a running style for six-legged robots that significantly improves on the traditional nature-inspired method of movement.

The research, conducted by scientists at the École Polytechnique Fédérale de Lausanne (EPFL) and the University of Lausanne (UNIL) in Switzerland, found that as long as the robots are not equipped with insect-like adhesive pads, it is faster for them to move with only two legs on the ground at any given time.

Robotics has in the past few years made heavy use of biomimicry – the practice of mimicking natural systems – resulting in six-legged robots being designed to move like insects. In nature, insects use what is known as a tripod gait, where they have three legs on the ground at a time, so it had been assumed that this was the most efficient way for similarly legged robots to move.

However, by undertaking a series of computer simulations, tests on robots and experiments on Drosophila melanogaster – better known as the common fruit fly – the scientists found that the two-legged approach, which they have dubbed the bipod gait, results in faster and more efficient movement.

The core goal of the research, which is published today in the journal Nature Communications, was to confirm whether the long-held assumption that a tripod gait was best was indeed correct.

“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, study co-lead and corresponding author.

Initially, this involved the use of a simulated insect model based on the common fruit fly and an algorithm designed to mimic different evolutionary stages. This algorithm simulated different potential gaits to create a shortlist of those that it deemed to be the fastest.

This, however, shed light on why insects have a tripod gait – and why it may not be the best option for robots. The simulations showed that the traditional tripod gait works in combination with the adhesive pad found on the ends of insects’ legs to make climbing over vertical surfaces such as rocks easier and quicker.

Robots, however, are typically designed to walk along flat surfaces, and so the benefits of such a gait are lost.

“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”.

Study co-lead authors Robin Thandiackal (left) and Pavan Ramdya with the six-legged robot used in the research. Images courtesy of EPFL/Alain Herzog

To for always corroborate the simulation’s findings, the researchers built a six-legged robot that could move either with a bipod or tripod gait, and which quickly confirmed the research by being faster when moving with just two legs on the ground at once.

However, they went further by confirming that the adhesive pads were in fact playing a role in the insect’s tripod movement.

They did this by equipping the fruit flies with tiny polymer boots that would cover the adhesive pads, and so remove their role in the way the insects moved. The flies’ responses confirms their theory: they began moving with a bipod-like gate rather than their conventional tripod-style movement.

“This result shows that, unlike most robots, animals can adapt to find new ways of walking under new circumstances,” said study co-lead author Robin Thandiackal.

As bizarre as the research sounds, it provides valuable new insights both for roboticists and biologists, and could lead to a new standard in the way that six legged robots are designed to move.

“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,” added Thandiackal. “We believe that our work represents an important contribution to the study of animal and robotic locomotion.”

Researchers discover remains of “Triassic Jaws” who dominated the seas after Earth’s most severe mass extinction event

Researchers have discovered the fossil remains of an unknown large predatory fish called Birgeria: an approximately 1.8-meter-long primitive bony fish with long jaws and sharp teeth that swallowed its prey whole.

Swiss and US researchers led by the Paleontological Institute and Museum of the University of Zurich say the Birgeria dominated the sea that once covered present-day Nevada one million years after the mass extinction.

Its period of dominance began following “the most catastrophic mass extinction on Earth”, which took place about 252 million years ago – at the boundary between the Permian and Triassic geological periods.

Image courtesy of UZH. Featured image courtesy of Nadine Bösch

Up to 90% of the marine species of that time were annihilated, and before the discovery of the Birgeria, palaeontologists had assumed that the first predators at the top of the food chain did not appear until the Middle Triassic epoch about 247 to 235 million years ago.

“The surprising find from Elko County in northeastern Nevada is one of the most completely preserved vertebrate remains from this time period ever discovered in the United States,” emphasises Carlo Romano, lead author of the study.

Although, species of Birgeria existed worldwide. The most recent discovery belongs to a previously unknown species called Birgeria Americana, and is the earliest example of a large-sized Birgeria species, about one and a half times longer than geologically older relatives.

The researchers say the discovery of Birgeria is proof that food chains recovered quicker than previously thought from Earth’s most devastating mass extinction event.

According to earlier studies, marine food chains were shortened after the mass extinction event and recovered only slowly and stepwise.

However, finds such as the newly discovered Birgeria species and the fossils of other vertebrates now show that so-called apex predators (animals at the very top of the food chain) already lived early after the mass extinction.

“The vertebrates from Nevada show that previous interpretations of past biotic crises and associated global changes were too simplistic,” said Romano.

Revolutionary DNA sunscreen gives better protection the longer its worn

Researchers have developed a ground-breaking sunscreen made of DNA that offers significant improvements over conventional versions.

Unlike current sunscreens, which need to be reapplied regularly to remain effective, the DNA sunscreen improves over time, offering greater protection the longer it is exposed to the sun.

In addition, it also keeps the skin hydrated, meaning it could also be beneficial as a treatment for wounds in extreme or adverse environments.

Developed by researchers from Binghamton University, State University of New York, the innovative sunscreen could prove essential as temperatures climb and many are increasingly at risk of conditions caused by excessive UV exposure, such as skin cancer.

“Ultraviolet (UV) light can actually damage DNA, and that’s not good for the skin,” said Guy German, assistant professor of biomedical engineering at Binghamton University.

“We thought, let’s flip it. What happens instead if we actually used DNA as a sacrificial layer? So instead of damaging DNA within the skin, we damage a layer on top of the skin.”

The DNA sunscreen has the potential to become a standard, significantly improving the safety of spending time in the sun

The research, which is published today in the journal Scientific Reports, involved the development of thin crystalline DNA films.

These films are transparent in appearance, but able to absorb UV light; when the researchers exposed the film to UV light, they found that its absorption rate improved, meaning the more UV is was exposed to, the more it absorbed.

“If you translate that, it means to me that if you use this as a topical cream or sunscreen, the longer that you stay out on the beach, the better it gets at being a sunscreen,” said German.

The film will no doubt attract the attention of sunscreen manufacturers, who will likely be keen to commercialise such a promising product. However, the researchers have not said if there is any interest as yet, and if there is any clear timeline to it becoming a commercial product.

 

The film’s properties are not just limited to sun protection, however. The DNA film can also store water at a far greater rate than conventional skin, limiting water evaporation and increasing the skin’s hydration.

As a result, the film is also being explored as a wound covering, as it would allow the wound to be protected from the sun, keep it moist – an important factor for improved healing – and allow the wound to be monitored without needing to remove the dressing.

“Not only do we think this might have applications for sunscreen and moisturizers directly, but if it’s optically transparent and prevents tissue damage from the sun and it’s good at keeping the skin hydrated, we think this might be potentially exploitable as a wound covering for extreme environments,” said German.