Forskere udvikler nyt materiale, der er i stand til at tænke

Nogen banker din skulder. De organiserede berøringsreceptorer i din hud sender en besked til din hjerne, som behandler informationen og dirigerer dig til at kigge til venstre, i retning af hanen. Nu har forskere fra Penn State og US Air Force udnyttet denne behandling af mekanisk information og integreret den i konstruerede materialer, der "tænker".

Værket udgivet i dag i Nature , hængsler på et nyt, rekonfigurerbart alternativ til integrerede kredsløb. Integrerede kredsløb er typisk sammensat af flere elektroniske komponenter anbragt på et enkelt halvledermateriale, normalt silicium, og de kører alle typer moderne elektronik, inklusive telefoner, biler og robotter. Integrerede kredsløb er videnskabsmænds realisering af informationsbehandling svarende til hjernens rolle i den menneskelige krop. Ifølge hovedforsker Ryan Harne, James F. Will Career Development Associate Professor of Mechanical Engineering ved Penn State, er integrerede kredsløb den kernebestanddel, der er nødvendig for skalerbar beregning af signaler og information, men de er aldrig før blevet realiseret af forskere i andre sammensætninger end silicium halvledere.

Hans teams opdagelse afslørede muligheden for, at næsten ethvert materiale omkring os kan fungere som sit eget integrerede kredsløb:at være i stand til at "tænke" på, hvad der sker omkring det.

"Vi har skabt det første eksempel på et ingeniørmateriale, der samtidigt kan sanse, tænke og handle på mekanisk stress uden at kræve yderligere kredsløb for at behandle sådanne signaler," sagde Harne. "Det bløde polymermateriale fungerer som en hjerne, der kan modtage digitale strenge af information, som derefter behandles, hvilket resulterer i nye sekvenser af digital information, der kan kontrollere reaktioner."

Det bløde, ledende mekaniske materiale indeholder rekonfigurerbare kredsløb, der kan realisere kombinationslogik:når materialet modtager ydre stimuli, omsætter det inputtet til elektrisk information, som derefter behandles for at skabe udgangssignaler. Materialet kunne bruge mekanisk kraft til at beregne kompleks aritmetik, som Harne og hans team demonstrerede, eller detektere radiofrekvenser til at kommunikere specifikke lyssignaler, blandt andre potentielle oversættelseseksempler. Mulighederne er ekspansive, sagde Harne, fordi integrerede kredsløb kan programmeres til at gøre så meget.

"Vi opdagede, hvordan man bruger matematik og kinematik - hvordan de individuelle bestanddele af et system bevæger sig - i mekanisk-elektriske netværk," sagde Harne. "Dette gjorde det muligt for os at realisere en grundlæggende form for intelligens i ingeniørmaterialer ved at facilitere fuldt skalerbar informationsbehandling, der er iboende for det bløde materialesystem."

According to Harne, the material uses a similar "thinking" process as humans and has potential applications in autonomous search-and-rescue systems, in infrastructure repairs and even in bio-hybrid materials that can identify, isolate and neutralize airborne pathogens.

"What makes humans smart is our means to observe and think about information we receive through our senses, reflecting on the relationship between that information and how we can react," Harne said.

While our reactions may seem automatic, the process requires nerves in the body to digitize the sensory information so that electrical signals can travel to the brain. The brain receives this informational sequence, assesses it and tells the body to react accordingly.

For materials to process and think about information in a similar way, they must perform the same intricate internal calculations, Harne said. When the researchers subject their engineered material to mechanical information—applied force that deforms the material—it digitizes the information to signals that its electrical network can advance and assess.

The process builds on the team's previous work developing a soft, mechanical metamaterial that could "think" about how forces are applied to it and respond via programmed reactions, detailed in Nature Communications last year. This earlier material was limited to only logic gates operating on binary input-output signals, according to Harne, and had no way to compute high-level logical operations that are central to integrated circuits.

The researchers were stuck, until they rediscovered a 1938 paper published by Claude E. Shannon, who later became known as the "father of information theory." Shannon described a way to create an integrated circuit by constructing mechanical-electrical switching networks that follow the laws of Boolean mathematics—the same binary logic gates Harne used previously.

"Ultimately, the semi-conductor industry did not adopt this method of making integrated circuits in the 1960s, opting instead to use a direct-assembly approach," Harne said. "Shannon's mathematically grounded design philosophy was lost to the sands of time, so, when we read the paper, we were astounded that our preliminary work exactly realized Shannon's vision."

However, Shannon's work was hypothetical, produced nearly 30 years before integrated circuits were developed, and did not address how to scale the networks.

"We made considerable modifications to Shannon's design philosophy in order for our mechanical-electrical networks to comply to the reality of integrated circuit assembly rules," Harne said. "We leapt off our core logic gate design philosophy from the 2021 research and fully synchronized the design principles to those articulated by Shannon to ultimately yield mechanical integrated circuit materials—the effective brain of artificial matter."

The researchers are now evolving the material to process visual information like it does physical signals.

"We are currently translating this to a means of 'seeing' to augment the sense of 'touching' we have presently created," Harne said. "Our goal is to develop a material that demonstrates autonomous navigation through an environment by seeing signs, following them and maneuvering out of the way of adverse mechanical force, such as something stepping on it."

Other authors of the paper include Charles El Helou, doctoral student in mechanical engineering at Penn State, and Benjamin Grossman, Christopher E. Tabor and Philip R. Buskohl from the U.S. Air Force Research Laboratory. + Udforsk yderligere

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