?Our materials mimic those of the human muscle, responding quickly to electrical impulses, instead of slowly for mechanisms driven by hydraulics.?
?Dr Adrian Koh, National University of Singapore

If robotics, especially humanoid robotics, is to ever achieve its full potential, contributions from chemistry are absolutely vital. New compounds of plastics and metals in ever-novel combinations and fusings offering lightweight, titanium-strength skeletal systems; strong, elastic muscles; pliant yet resilient skin, as well as compact, powerful batteries are beginning to trickle from materials science and nanotechnology labs. Their impact could well be a quantum leap for robot evolution.

One such breakthrough are polymer muscles. The polymer that mimics human muscles is a recent development by a team of engineers headed by Dr Adrian Koh from the Engineering Science Program and Department of Civil and Environmental Engineering at the National University of Singapore (NUS).

Abundant robot applications and market potential

The team fabricated a novel form of ?robotic? muscle from polymers that are capable of carrying loads eighty times its own weight and stretch to five times its original length?under load! Such a discovery has vast potential for robotics, especially for co-worker robots.

The polymer, when made into artificial muscles, could potentially convert and store energy to power robots, astoundingly, only after recharging for less than a minute.

The team?s feat represents a first in robotics, paving the way, they say, for the building of ?human-like robots with superhuman power and capability.?

Dr Koh?s four-member team has been working on the project since July 2012.

Super, artificial muscles

PHYS.ORG?Robots, no matter how intelligent, are restricted by their muscles which are able to lift loads only half its own weight ? about equivalent to an average human’s strength (though some humans could lift loads up to three times their weight).

Artificial muscles have been known to extend to only three times its original length when similarly stressed. The muscle’s degree of extendibility is a significant factor contributing to the muscle’s efficiency as it means that it could perform a wider range of operations while carrying heavy loads.

Explaining how he and his multidisciplinary team managed to design and create their novel superhuman muscles, Dr Koh said, “Our materials mimic those of the human muscle, responding quickly to electrical impulses, instead of slowly for mechanisms driven by hydraulics. Robots move in a jerky manner because of this mechanism.

Now, imagine artificial muscles which are pliable, extendable and react in a fraction of a second like those of a human. Robots equipped with such muscles will be able to function in a more human-like manner ? and outperform humans in strength.”

In order to achieve this, Dr Koh and his team have used polymers which could be stretched over 10 times their original length. Translated scientifically, this means that these muscles have a strain displacement of 1,000 per cent.

Understanding of the fundamentals

“We put theory to good use. Last year, we calculated theoretically that polymer muscles driven by electrical impulse could potentially have a strain displacement of 1,000 per cent, lifting a load of up to 500 times its own weight. So I asked my students to strive towards this Holy Grail, no matter how impossible it sounded,” he said.

Though they could only achieve a modicum of their target, it is a first in robotics. For his contributions, Dr Koh was awarded the Promising International Researcher Award at the 3rd International Conference on Electromechanically-Active Polymer Transducers and Artificial Muscles in June 2013, held in Zurich, Switzerland.

The Award recognizes young researchers from outside Europe, who have made significant contributions in the field of electromechanically-active polymers, and display promise to successful career in the field.

Polymer muscles

“Our novel muscles are not just strong and responsive. Their movements produce a by-product?energy. As the muscles contract and expand, they are capable of converting mechanical energy into electrical energy.

Due to the nature of this material, it is capable of packing a large amount of energy in a small package. We calculated that if one were to build an electrical generator from these soft materials, a 10kg system is capable of producing the same amount of energy of a 1-ton electrical turbine” Dr Koh said.

This means that the energy generated may lead to the robot being self-powered after a short period of charging ? which is expected to be less than a minute.

Patent filing

Dr Koh said they are still beefing up their muscles. They will also be filing a patent for their successful formula of materials and right degree of electric impulses. And in about three to five years, they expect to be able to come out with a robotic arm, about half the size and weight of a human arm which can wrestle with that of a human being’s?and win.

Powerful artificial muscles need not only be used in robots, said Dr Koh.

“Think of how efficient cranes can get when armed with such muscles,” said Dr Koh.

The research team plans to work further with researchers from Materials Science, Mechanical Engineering, Electrical & Computer Engineering, as well as Bioengineering to create robots and robotic limbs which are more human-like in both functions and appearance.