By Evan Ackerman
Conventional quadrotors are what’s called underactuated robots, which means that they can move in more ways than they have independent control over. For example, they can happily yaw around to any angle you want while otherwise stationary, but if you ask them to pitch or roll, they can’t do it without also changing their position: if you try to roll a quadrotor left, the whole robot is going to fly left, and if you try to fly a quadrotor left, the whole robot is going to roll left.
Having controls coupled together like this places some restrictions on what you can do with quadrotors, but a new design presented yesterday at the 2013 IEEE International Conference on Robotics and Automation (ICRA) gets around all of that with propellers that tilt.
This level of control turns the quadrotor into a fully-actuated robot: you have complete control over its position and orientation, and as the video shows, this lets the quadrotor do things that would otherwise be impossible for a conventional quadrotor without those tilting propellers.
There are tons of ways in which this new capability can be useful, but I’d say the most obvious one is for any quadrotor that carries a camera (which is pretty much all of them nowadays): instead of having to either rely on a static camera or invest in a complicated, heavy, and expensive gimbaled mount, you can now use the entire quadrotor as a pan and tilt camera platform.
Future work will improve the capabilities of this prototype (it’s called the “omnicopter”), and the researchers also plan to start experimenting with environmental interaction tasks that require orientation control, like using tools.
"First Flight Tests for a Quadrotor UAV with Tilting Propellers," by Markus Ryll, Heinrich H. Bulthoff, and Paolo Robuffo Giordano from the Max Planck Institute for Biological Cybernetics, was presented this week at ICRA 2013 in Germany.
practical value for this development?
a large drain on the battery when the energy goes in one direction and some in the opposite direction, it is best to do if you want to suspension, easier and more reliable
To take photos up you just make a V frame
I have to disagree. What if you wanted to take pictures above the quadrotor at varying angles? What if you want to take pictures of something that is occluded due your rotors being in the way? Or even as exactly as you stated, flying in higher constrained spaces.
As far as efficiency concerns go, the Boeing QTR, SUAVI, or the NASA Large Civilian Tilt Rotor are real examples of actively researched quadtiltrotor designs to improve the efficiency, range, mission capability and flight duration of these type of aircraft.
A 2 axis gimbal would achieve the same thing for a camera.
As for efficiency I am not sure what you mean, with a non square aspect and the quad rotated you lose efficiency anyway...
The point is that it is a fully actuated system, i.e. it can position itself in any orientation/trajectory. So for instance, if you put a camera on it, you could take pictures/video of something in any orientation, like a confined space. On a normal quadrotor this is not physically possible. There are other advantages too, like certain designs could fly much more efficiently by using wings with rotating propellers.
Looks like the tether is just a safety tether, and it looks like during a lot of the video there is no tension in it either.
Now to make it work without a tether.
I would recommend to implement a full heli swashplate on each motor so things get a little bit more challenging. And an combustion engine with generator to produce some sweet vibration for the algorithm.....
Man if this thing had variable pitch, it could fly in almost any orientation. It could also move so quick.