This is the closest so far scientists have reached in terms of making lifelike robotic muscles. Researchers from Columbia University’s Creative Machine Lab have developed a new type of soft-bodied robotic muscle that is three times stronger than natural ones. This development is a major breakthrough in designing robots whose actions and mechanisms mimic actual biological parts.
“We’ve been making great strides toward making robots minds, but robot bodies are still primitive,” said Hod Lipson, the leader of the research team and a professor of mechanical engineering. “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.”
To create a synthetic muscle that has high stress-high strain-low density properties, researchers turned to silicone rubber and introduced microbubbles of ethanol to attain extraordinary qualities. Not only does this mixture gives elastic properties, it also imparts extreme expansion-contraction properties seen in other material systems. The composition allows the synthetic muscle to expand up to 900% when electrically heated to 80ºC. Moreover, the material is easy to fabricate, low in cost and safe for the environment.
“Our soft functional material may serve as robust soft muscle, possibly revolutionizing the way that soft robotic solutions are engineered today,” said Aslan Miriyev, one of the researchers in the Creative Machines Lab. “It can push, pull, bend, twist, and lift weight. It’s the closest artificial material equivalent we have to a natural muscle.”
By virtue of its soft composition, the robotic muscle veers away from the limitations that hound modern machines. Robots nowadays are rigid, making it hard for them to do delicate tasks, like picking an object, without causing any damage. This soft-bodied device can grasp and make motions that require a certain level of finesse and dexterity. This bodes well in future applications where delicate movements are necessary, like in the areas of healthcare and manufacturing.
But the robotic muscle is not all about finesse; it also boasts of power as it can lift up to 1,000 times its own weight and has the 15 times strain density of a natural muscle. As the device is electrically actuated (movement is made with a low-power charge that runs through a thin resistive wire), it can function independently without bulky attachments. This is another advantage of this device over modern robots which require pneumatic or hydraulic systems that take a lot of space.
To make the synthetic muscle, the silicone-based material is 3D-printed into the desired shape. It is electrically actuated and then tested for various robotic applications. If computer-controlled, the device can perform wide range of motions in almost any design
Going forward, researchers intend to build on this creation by replacing the resistive wire with a conductive material in order to increase response time and shelf life. In the long term, they plan to apply artificial intelligence to learn to control the muscle, which could be the last step towards mimicking natural motion.
The paper is published in the journal Nature Communications.