This thing is so nimble in the air yet has a fraction of the complexity of a regular helicopter. I wonder if this method will scale up to "full size"?
This is such a neat idea, but I wonder if it suffers from vibration problems. Because the blades are mounted on pivots, whenever you've commanding differential pitch, the high angle-of-attack blade will incur more drag and so lag slightly more than the low angle-of-attack blade. Thus the blades won't be exactly opposite each other anymore, creating vibration. Perhaps the blades are spinning so fast this is not a big deal? Probably would be if you scaled up though.
Reminds me of PWM [1] on old PC speakers. Many old computers (e.g. of the 286 era) had a speaker that was only able to generate square tones. By controlling the start and duration of the pulses, programmers could generate sounds that were a lot more rich than what you would expect from "plain" square waves [2].<p>In a way this is similar: they start with two actuators that seem very limited in what they can accomplish: you can only speed them up and down. By modulating the speed of both motors in sync, they are able to control that cheap rotor mechanism they came up with, achieving 6DoF [3]<p>1: <a href="http://en.wikipedia.org/wiki/Pulse-width_modulation" rel="nofollow">http://en.wikipedia.org/wiki/Pulse-width_modulation</a><p>2: <a href="https://www.youtube.com/watch?v=FSe3ysBrXq4" rel="nofollow">https://www.youtube.com/watch?v=FSe3ysBrXq4</a><p>3: <a href="http://en.wikipedia.org/wiki/Six_degrees_of_freedom" rel="nofollow">http://en.wikipedia.org/wiki/Six_degrees_of_freedom</a>
I wonder if this will cause some parts of the motor to heat up more; since the blade is 1:1 rotations with the motor then driving more torque (power) during certain phases of the cycle will put more watts on certain coils.<p>It's a cool idea. Human size helicopters would love to avoid all that blade-pitch complexity. :)
Very clever! I hadn't fully understood the mechanical complexities involved in a standard single-rotor helicopter. I just thought that they were hard to fly manually (which made me very confused to see all the computer-controlled quadrocopters - why didn't they use just one rotor?)
At first viewing of the video I didn't understand why the body doesn't spin around with one rotor and a pair of blades. That was some magic! Then looked at the picture again and saw another rotor underneath. Pretty neat to have two rotors counteracting each other.