The humanoid “robots” that walk, talk, and screw around in shows like HBO’s Westworld are unsettlingly realistic, largely because of how they move. Their smooth, lifelike motions, coupled with the premise that they are machines, put them firmly in the uncanny valley. We’re used to spastic robots like the fictional R2-D2 or the real-life Pepper — cute, stuttering machines with endearingly clumsy moves are the robots we know and love.

But new synthetic muscle developed by researchers at Columbia University in New York looks to be the next step toward smooth-moving machines becoming part of our reality. In a study published in Nature Communications, research group leader Hod Lipson, Ph.D., and his team explain that synthetic muscle can change in elasticity and volume because the muscle made of a silicone rubber matrix contains ethanol-carrying microbubbles. The results are robotic muscles like this:

Engineers from the school’s Creative Machines Lab announced Tuesday that they have developed a 3D printable synthetic soft muscle that’s three times stronger than actual human muscle. This material is the first synthetic muscle able to withstand both high actuation stress and high strain, a breakthrough that means the team has “overcome one of the final barriers to making lifelike robots.”

“We’ve been making great strides toward making robot minds, but robot bodies are still primitive,” Lipson explains. “This is a big piece of the puzzle and, like biology, the new actuator can be shaped and reshaped a thousand ways.”

Soft robotics are designed to mimic natural motion. Aslan Miriyev/Columbia Engineering

This synthetic muscle can push, pull, bend, twist, and lift weight, which makes it the closest match to natural muscle that’s ever been created.

This bubble-filled mixture can be 3D-printed into the desired shape, then electrically actuated — that is, brought to life — by inserting a thin, resistive wire. With a strain density that’s 15 times larger than natural muscle, robots equipped with this muscle could hypothetically lift 1,000 times their own weight.

This 3D-printed synthetic muscle is considered a "breakthrough in soft robotics." Aslan Miriyev/Columbia Engineering

Previous synthetic muscle technology has been dependent on an external compressor or high voltage equipment, but robots equipped with this new synthetic material should be able to function untethered. This, combined with the fact that soft robots can more easily replicate natural motion, means that robots equipped with these new muscles will better be able to help humans with tasks that require actions like gripping and picking things up.

It’s the hope that soft robots will eventually help humans with a variety of tasks, including providing medical care, operating in dangerous areas like nuclear disaster sites, and manual labor.

What’s Next

Lipson and his team say that their next step is to add in an artificial intelligence that can control their “low-cost” muscle — adding a bit of brain to their manufactured brawn.

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