Project Website http://acl.mit.edu/projects/vpitch_quad.html
This project aims to develop a varible-pitch quadrotor capable of aggressive aerobatic manuvers which stretch beyond the current abilities of typical fixed-pitch quadrotors.
Fixed-pitch quadrotors are limited in their ability to make abrupt changes in thrust or to create negative thrust. The control bandwidth of a typical fixed-pitch quadrotor is restricted by the rotational inertia of the motor and propellers; however, with a variable-pitch design, the control bandwidth is increased. The variable-pitch actuators allow the propellers to change from a full positive pitch to a full negative pitch in rougly 0.07 seconds while the motor remains at maximum RPM, allowing the quadrotor to change from maximum positive thrust to maximum negative thrust extremely fast.