Aggressive Quad-rotors Round-up

The University of Pennsylvania GRASP Lab has been doing pretty amazing job with their quad-rotors UAVs. These robots can do pretty impressive manoeuvres that humans would have a very hard  time to imitate. They fly trough free-falling hoops and small windows, they cooperate at grasping and transporting objects, they perch, and much more. Have a look at the videos below in order to witness the quad-rotors in all their aggressiveness. http://www.youtube.com/watch?v=MvRTALJp8DM http://www.youtube.com/watch?v=geqip_0Vjec http://www.youtube.com/watch?v=YBsJwapanWI http://www.youtube.com/watch?v=icdb9ftdZOw