Flying robot repairs broken wings itself
Inspired by the resilience of bumblebees, researchers at the Massachusetts Institute of Technology (MIT) have developed a method for bug-sized flying robots to repair severe damage to their artificial muscles.
Bumblebees are not the best fliers. They sometimes bump into each other when they land on a flower to feed. That doesn't do their wings any good at all. But despite many tiny cracks and holes in their wings, bumblebees can still fly. Flying robots, on the other hand, are not as resilient. With holes in their propulsion system, the chances are pretty good that they'll crash. "We've spent a lot of time understanding the dynamics of soft artificial muscles. And we've achieved a level of resistance to damage comparable to that of insects," says MIT researcher Kevin Chen.
The tiny rectangular robots being developed in Chen's lab weigh little more than a paper clip. The wings at each corner are powered by dielectric elastomer actuators, which are soft artificial muscles that use mechanical forces to make the wings beat quickly. They are made of layers of elastomer sandwiched between two ultra-thin electrodes. When a voltage is applied, the elastomer begins to flap. The tiny robot is supplied with electricity from outside via ultra-thin cables.
Balancing act with carbon tubes
If damage occurs, it can be repaired by applying a higher voltage; the wing virtually heals itself. This effect is not new, but Chen and his team have optimized it. They use carbon nanoparticles as electrodes, super-strong but extremely small molecules that are shaped like tubes. The challenge was to reduce the amount of carbon molecules to lower the energy required for repairs. "We had to find the optimal point between the amount of carbon tubes and the energy required for the repair mechanism," Chen says. Even with perforated wings, he says, the tiny animal can still fly.
