The future of useful engineering ‘living’ machines?

New soft, mechanical metamaterials can “think” about how forces are applied to it and react through pre-programmed reactions. Credit: Jennifer M. McCann / Elizabeth Flores-Gomez Murray, MRI of Penn

Created, autonomous machines combined with artificial intelligence have long been a major science fiction, often in the role of villains like the Cylons in restarting “Battlestar Galactica,” beings composed of biological and constructed materials. But what if these autonomous soft machines were … useful?

This is the vision of a team of Penn State and U.S. Air Force researchers, highlighted in a recent paper published in Nature Communications. These researchers have produced a soft, mechanical metamaterial that can “think” about how forces are applied to it and respond to programmed reactions. This platform has great potential for a variety of applications, from medical treatments to environmental improvements.

“We have created soft, mechanical metamaterials with flexible, conductive polymer networks that can compute all digital logic computations,” said Ryan Harne, James F. Will, associate professor of career development, Penn State. “Our article reports on how to create decision-making functionality in constructed materials in a way that could support future soft, autonomous engineering systems that are embedded in the basic elements of life forms and are programmed to provide useful services to people. This could include assistance maintain a sustainable and robust infrastructure, control pollutants and pathogens in the air and water, help heal patient wounds and more. “

The processes of human thought are based on logic, notes Harne, which is similar to the logic of logic in mathematics. This approach uses binary inputs to process binary control outputs – using only the “on” and “off” sequences to represent all thoughts and cognitions. The soft materials created by the research team “think” using the reconfiguration of conductive polymer networks. The mechanical force applied to the materials connects and reconnects the network.

Using a low-voltage input to the materials, the research team created a way for the soft material to decide how to react according to the output voltage signal from the reconfigured conductive polymer network.

The type of logic Harne and his team use goes beyond pure mechanical logic, which is a way of using combinations of bistable switches – two steady state switches – to represent the “0” and “1” binary sequence of numbers. They found that when they used pure mechanical logic, the researchers eventually got stuck because certain logical operations could not be constructed.

“You’ve reached a point where you can’t actually process all eight logic gates,” Harne said. “You can process four of them, but you can’t process the last four. We’ve figured out how electrical signals are included along with mechanical signals, which allows us to process all the logic inputs used in modern digital computing.”

The key to the realization of all logic gates was in the combination of electrical polymer mesh with soft, deformable material. The researchers created logical operations by simultaneously reconfiguring the soft material and the electrically conductive network.

This also ensures that the binary output is in the form of electricity, which is required to drive an activation mechanism that forces the material to react to the applied mechanical force. The combination of electrical and mechanical signals allows the machine to move to get out of the way or bounce in a certain direction.

Harne and team want to go beyond one material and design something more complex.

“I have a vision of how scientists and engineers can create a constructed living system that helps society,” Harne said. “All you need to do is connect all the functions of life forms. And when you do, the building blocks of engineering life are available to you.”

While all of this seems like science fiction, Harne believes it has huge potential.

“It’s a bit sci-fi, I have to admit it and I’ll say, I had colleagues who thought I was a bit crazy,” Harne said. “But if we as engineers and scientists understand all the things that make up life, why don’t we try to create engineered living beings who can help people?”

Hierarchical mechanical metamaterials offer more stable configurations

More information:
Charles El Helou et al. Digital logic doors in soft, conductive mechanical metamaterials, Nature Communications (2021). DOI: 10.1038 / s41467-021-21920-y

Provided by Pennsylvania State University

Citation: The future of useful engineering ‘living’ machines? (2021, April 20) retrieved April 20, 2021 from

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