Fly-sized robot flaps wings to fly and hover

Nature : An 80-mg robot is the first wing-flapping design that can both fly and hover. Too small to carry its own power source, the robot is tethered to the ground. It is also connected to a computer that monitors the robot’s motion and adjusts its attitude. The robot flaps its wings 120 times per second, roughly the same rate as a housefly. Its wings, which are made of layers of a thin polyester material supported by carbon fiber “ribs,” are moved by piezoelectric crystals that stretch and contract in response to changes in voltage applied to them. Kevin Ma of Harvard University and his colleagues found that the physical structures of their design were too small to be created by conventional methods. Instead they manufactured two-dimensional pieces with flexible hinges that allowed them to fold the pieces into three-dimensional structures. Ma believes that in the next 5 to 10 years batteries may reach usable sizes to allow for untethered flight. Small flying robots would be incredibly useful for search and rescue missions or even for pollinating crops.