[seanwitte]

If you're planning on keeping the helicopter inside, a novel way to track your position would be with the CMU cam pointed at a colored target. Indoors, under controlled conditions, you could also use one of the Sharp IR proximity sensors to measure your altitude.

Here are some comments based on personal experience. Your ideal platform would be a large fixed-pitch helicopter like the Lite Machines Corona. There are only four channels to control and it can carry some weight if you upgrade to a brushless motor. A small fixed pitch helicopter, like the Honey Bee or Dragonfly, doesn't have enough lift to carry the extra gear required. You will have to upgrade to brushless motors and lithium polymer batteries, which turns your $100.00 toy into a $350.00 money pit. I don't know how it would work in reality, but in theory you could use a futaba heading-hold gyro on each axis to keep the helicopter stable in roll, pitch, and yaw. It won't keep the helicopter in place, but it should keep it stable on each axis. Those are about $100.00 each, so you're up to about $650.00. Your primary control inputs would be the throttle, which controls altitude, the ailerons, which controls side/side, and the pitch, which controls forwards/backwards.

Here is another way to approach it. Get a coaxial helicoper like the ESky Co-Co Lama or Blade CX. Put a brightly colored target on the nose that that you can track with the CMU cam. Build a robot that can manipulate the heli transimitter and build a robot that "flys" the helicopter. Based on the camera feedback you'd be able to determine its altitude and orientation. If the target is square then the height would correlate to the range and the width would correlate to its orientation. You control loop would need to try and keep the nose pointed at the camera at all times, then apply throttle/aileron/pitch to keep it in one place. Those helis are very stable and almost fly themselves.