Researchers have made rapid advances in computer miniaturization, which makes it possible to develop smaller robot brains. Unfortunately, existing actuators remain bulky which limits the possibilities for smaller robots or intelligent prosthetic limbs. Existing soft-actuator technologies require external equipment to pneumatically or hydraulically inflate plastic skins with air or liquid, much like a bicycle pump inflates a tire or the push of a pedal activates a car’s brakes. The limitations of those bulky external components have prevented the creation of robots that can move and work independently.

Researchers at Columbia Engineering developed a 3D-printable synthetic soft muscle with no such limitations and that can lift 1,000 times its own weight. Lead author of the study Aslan Miriyev, a postdoctoral researcher in the Creative Machines Lab, used a silicone rubber matrix with ethanol distributed throughout in micro-bubbles to achieve an actuator with high strain and high stress coupled with low density. A thin resistive wire with low power actuates the artificial muscle after it was 3D-printed into the desired shape. “We’ve been making great strides toward making robots’ minds, but robot bodies are still primitive,” said Hod Lipson of the Creative Machines Lab. “This is a big piece of the puzzle and, like biology, the new actuator can be shaped and reshaped a thousand ways. We’ve overcome one of the final barriers to making lifelike robots.”

In the short term, the advancement in soft material robots – which can replicate natural motion – could be used in areas such as manufacturing and healthcare, where robots must interact with humans. In the long term, researchers will use artificial intelligence to control the man-made muscle. “Our soft functional material may serve as robust soft muscle, possibly revolutionizing the way that soft robotic solutions are engineered today,” said Miriyev. “It can push, pull, bend, twist, and lift weight. It’s the closest artificial material equivalent we have to a natural muscle.”