WebZine
2017. 12
What's New
Origami-inspired muscles are both soft and strong, and can be made for less than $1
By Lindsay Brownell
(CAMBRIDGE, Mass.) — Soft robotics has made leaps and bounds over the last decade as researchers around the world have experimented with different materials and designs to allow once rigid, jerky machines to bend and flex in ways that mimic and can interact more naturally with living organisms. However, increased flexibility and dexterity has a trade-off of reduced strength, as softer materials are generally not as strong or resilient as inflexible ones, which limits their use.
Now, researchers at the Wyss Institute at Harvard University and MIT’s Computer Science and Artificial Intelligence Laboratory (CSAIL) have created origami-inspired artificial muscles that add strength to soft robots, allowing them to lift objects that are up to 1,000 times their own weight using only air or water pressure, giving much-needed strength to soft robots. The study is published this week in Proceedings of the National Academy of Sciences (PNAS).
“We were very surprised by how strong the actuators [aka, “muscles”] were. We expected they’d have a higher maximum functional weight than ordinary soft robots, but we didn’t expect a thousand-fold increase. It’s like giving these robots superpowers,” says Daniela Rus, Ph.D., the Andrew and Erna Viterbi Professor of Electrical Engineering and Computer Science at MIT and one of the senior authors of the paper.
“Artificial muscle-like actuators are one of the most important grand challenges in all of engineering,” adds Rob Wood, Ph.D., corresponding author of the paper and Founding Core Faculty member of the Wyss Institute, who is also the Charles River Professor of Engineering and Applied Sciences at Harvard’s John A. Paulson School of Engineering and Applied Sciences (SEAS). “Now that we have created actuators with properties similar to natural muscle, we can imagine building almost any robot for almost any task.”
Each artificial muscle consists of an inner “skeleton” that can be made of various materials, such as a metal coil or a sheet of plastic folded into a certain pattern, surrounded by air or fluid and sealed inside a plastic or textile bag that serves as the “skin.” A vacuum applied to the inside of the bag initiates the muscle’s movement by causing the skin to collapse onto the skeleton, creating tension that drives the motion. Incredibly, no other power source or human input is required to direct the muscle’s movement; it is determined entirely by the shape and composition of the skeleton.
“One of the key aspects of these muscles is that they’re programmable, in the sense that designing how the skeleton folds defines how the whole structure moves. You essentially get that motion for free, without the need for a control system,” says first author Shuguang Li, Ph.D., a Postdoctoral Fellow at the Wyss Institute and MIT CSAIL. This approach allows the muscles to be very compact and simple, and thus more appropriate for mobile or body-mounted systems that cannot accommodate large or heavy machinery.
With heart-firming embrace, squishy device keeps blood pumping
By Beth Mole
Posted 20 Jan 2017 | 07:30 GMT
If it passes further tests, it could help millions of people with heart failure.
A good squeeze can definitely get the blood flowing. But the firm, rhythmic squeezes of an inflatable robot, can keep that blood flowing.
The device—a silicone sleeve ribbed with inflatable tubes—wraps around a waning heart and provides extra muscle-power to pump blood. In early tests, the heart-snuggling sleeve restored blood flow in six living pigs after they had suffered acute cardiac arrest, researchers reported Wednesday in Science Translational Medicine. If the thumping tech passes further testing, it could one day help prolong the lives of people with heart failure, an affliction that strikes around 40 million people worldwide.
It’s not the only device that helps weakened hearts to go on. But existing medical devices involve pumps and valves that carry risks of blood clotting and severe blood infections. So, an international team of researchers, headed by scientists at Harvard, set out to make a heart fortifier that doesn’t have to contact blood.
Their solution is the squishy silicone sleeve that blankets the whole heart and holds on with a suction device and a gripping gel. Embedded in the silicone are thin rings and spines of inflatable tubes, tethered to an external pump. The tubes inflate and collapse, causing the whole sleeve to contract and twist. The overall movement mimics the activity of the heart muscles and can be tuned to coordinate perfectly with each individual heart.
In experiments in pigs, the devices could almost completely restore blood flow following acute cardiac arrest. After the heart failure, the pigs' hearts pumped about 45 percent of the normal amount of blood. With the device, the blood output gushed up to 97 percent—around two liters per minute. The researchers also found that they could tweak the squeeze to compensate for different weaknesses in a heart, such as glitches with particular chambers.