Tiny automobile differential governs flight of aerial robots

It is envisaged that such devices could be used to investigate environmental hazards, forest fires, and other places too dangerous for people.

Their new approach is the first to passively balance the aerodynamic forces encountered by these flying devices, letting their wings flap asymmetrically in response to gusts of wind, wing damage, and other impediments likely to be experienced in ‘real-word’ scenarios.

’The drivetrain for an aerial microrobot shares many characteristics with a two-wheel-drive automobile,’ said Pratheev S Sreetharan, a graduate student in Harvard’s School of Engineering and Applied Sciences. ’Both deliver power from a single source to a pair of wheels or wings. But our PARITy (Passive Aeromechanical Regulation of Imbalanced Torques) differential generates torques up to 10 million times smaller than in a car, is 5mm long, and weighs about one-hundredth of a gram, a millionth the mass of an automobile differential.’

Scientists at institutions including the University of California, Berkeley, University of Delaware, University of Tokyo, and Delft University of Technology in the Netherlands are exploring aerial microrobots as cheap, disposable tools that might someday be deployed in search and rescue operations, agriculture, environmental monitoring, and exploration of hazardous environments.