Harvard engineers have developed an advanced version of their RoboBee which also happens to be the first flying microrobot powered by soft actuators.
The Harvard SEAS and Wyss Institute researchers contend that their resilient RoboBee can crash into walls, fall onto the floor, and collide with other RoboBees without being damaged.
“There has been a big push in the field of microrobotics to make mobile robots out of soft actuators because they are so resilient,” says postdoctoral fellow and first author Yufeng Chen.
“However, many people in the field have been skeptical that they could be used for flying robots because the power density of those actuators simply hasn’t been high enough and they are notoriously difficult to control.”
“Our actuator has high enough power density and controllability to achieve hovering flight.”
The electrically-driven soft actuators were developed in the lab of professor David Clarke.
These soft actuators are 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 Hertz, on par with the rigid actuators used previously in similar robots.
Soft actuators are known 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.
According to the Harvard team, the soft actuators can be easily assembled and replaced in these small scale robots.
To demonstrate various flight capabilities, the researchers built several different models of the soft-powered RoboBee.
A two-wing model could takeoff from the ground but had no additional control.
A four-wing, two actuator model could on the other hand fly in a cluttered environment, overcoming multiple collisions in a single flight.
An eight-wing, four-actuator model demonstrated controlled hovering flight – the first for a soft-powered flying microrobot.
According to coauthor and former SEAS graduate student Elizabeth Farrell, soft actuator-based RoboBees could come in handy while flying through rubble for search and rescue missions.
The researchers are currently working on increasing the efficiency of the soft-powered robot, which still lags far behind more traditional flying robots.
Image and content: Harvard Microrobotics Lab/Harvard SEAS