Flight of fancy

LOOKING to the natural world for engineering inspiration is an idea at least as old as Leonardo da Vinci. Copying nature directly, though, has often proved hard. For example, birds flap their wings to achieve both lift and propulsion, but flying machines that imitate this action have tended not to do well. Human engineering has found it easier to create aircraft by giving them fixed, rigid wings and propelling them with motors.

Air is not the only medium through which animals move by flapping, however. Many creatures flap wings, or wing-like structures, to “fly” through water. That is something human engineers can aspire to imitate because the buoyancy of water provides free lift and its density makes propulsion easier. And, as they write in this week’s Science, a group led by Kit Parker of Harvard University have done just that. They have built a robotic stingray (pictured above) that imitates the motion of its biological counterpart. Moreover, it does so not with the electric circuits and servomotors of conventional robots, but with muscle cells engineered to mimic the elegant undulations of a living…Continue reading
Source: Economist