Now that BigDog can throw concrete slabs like it's nobody's business, it would be a mistake to assume that the humble quadrotor isn't going through a similar evolution in form and function. Watch as this avian-inspired micro UAV uses its talons to snatch objects like an eagle.
To get the quadrotor to do this, engineers at the the University of Pennsylvania's GRASP Labs studied the way eagles do the same thing (a prime example of robotic biomimcry). First, they designed a talon-like articulate gripping arm (an actuated appendage), and then they watched how predatory birds perform their crucial dive, swoop, and snatch actions.
And indeed, mimicking the eagle's behavior was key. Engineers Justin Thomas, Joe J. Polin, Koushil Sreenath, and Vijay Kumar, wrote in their paper: "an eagle sweeps its legs and claws backwards during its capture phase, thereby reducing the relative velocity between the claws of the predator and the prey." By doing so, the eagle — and the quadrotor — use this backward strategy to to achieve a kind of near-zero relative velocity of the claw as it grasps the object without having to slow down.
Their quadrotor achieved success at pick-up velocities of 2 m/s (6 body lengths/second) and 3 m/s (9 body lengths/second).
The next phase will see the quadcopter perform the same thing, but without the benefit of the Vicon motion capture system.
Read the entire paper here (pdf).