Researchers have developed a microrobot called RoboBee powered by soft artificial muscles that can crash into walls, fall onto the floor, and collide with other RoboBees without being damaged. It is the first microrobot powered by soft actuators to achieve controlled flight.
Soft actuators were made using dielectric elastomers — soft materials with good insulating properties — that deform when an electric field is applied. By improving the electrode conductivity, the researchers were able to operate the actuator at 500 Hz, on par with the rigid actuators used previously in similar robots.
Another challenge when dealing with soft actuators is that the system tends to buckle and become unstable. To solve this challenge, the researchers built a lightweight airframe with a piece of vertical constraining thread to prevent the actuator from buckling. The soft actuators can be easily assembled and replaced in these small-scale robots.
To demonstrate various flight capabilities, several different models of the soft-powered RoboBee were built. A two-wing model could take off from the ground but had no additional control. A four-wing, two-actuator model could fly in a cluttered environment, overcoming multiple collisions in a single flight. The soft actuator provides an additional benefit because it can absorb impact better than traditional actuation strategies. This would be beneficial in potential applications such as flying through rubble for search and rescue missions.
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