From Robohub, an introduction to GimBall, a flying robot that can collide with objects seamlessly, from EPFL. Excerpt:
The concept
The inner frame comprises everything a flying robot needs to stabilize in flight: a coaxial motor, two control surfaces, the battery, an IMU and control electronics. In case of collision, GimBall’s spherical protective frame prevents obstacles from touching the inner frame and can passively rotate thanks to a gimbal system (hence the name). This way, the contact force does not affect the orientation of the inner frame, whose center of mass is also carefully centered. This allows the inner frame to always stay upright, and maintain the robot in stable flight.A conventional platform will be strongly affected by collisions, because its orientation is disturbed. GimBall keeps the orientation of its inner frame stable thanks to the gimbal system. Note that this is a side-view of a collision in the vertical plane, but the principle remains the same from all angles, since the protective cage rotates around all 3 axes.

Comments
It is just great! Very good idea
I played with one a couple of years ago, they are fun
https://www.youtube.com/watch?v=vTyNHj07BE0&feature=youtube_gda...
Hey, its only a matter of time before a knockoff helicopter ball becomes available from an overseas manufacturer!
It flew for .... several ... hundred meters. Then came an opportunistic branch.
By the way, I think it uses bascially the same flight controls as the t-hawk like vehicle that was blogged about a few days ago and for which we have a patch for arducopter.
It's similar but perhaps better than that japanese flying ball. Too bad they're not actually for sale anywhere so we can't all have one (without building it from scratch ourselves).
I wonder if random flight with bouncing off walls could give a rudimentary mapping of a space? I like how they sent it off with a compass heading in the woods, and it just bounced its way along to its goal! It does really remind me of watching an insect bounce off a glass window, or along a wall while trying to find its way out of a confined space.
I really like how people are thinking of simple solutions to what seem like complex problems. This and the fotokite recently demonstrated show how simple engineering can solve seemingly insurmountable problems.