This project aims to develop a variable-pitch quadrotor capable of aggressive aerobatic maneuvers 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 roughly 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.
Cutler, M., “Design and Control of an Autonomous Variable-Pitch Quadrotor Helicopter,” Master's thesis, Massachusetts Institute of Technology, Department of Aeronautics and Astronautics, 2012.
Cutler, M., and How, J. P., “Actuator Constrained Trajectory Generation and Control for Variable-Pitch Quadrotors,” AIAA Guidance, Navigation, and Control Conference (GNC), Minneapolis, Minnesota: 2012, pp. 1–15.
Cutler, M., Ure, N. K., Michini, B., and How, J. P., “Comparison of Fixed and Variable Pitch Actuators for Agile Quadrotors,” AIAA Guidance, Navigation, and Control Conference (GNC), Portland, OR: 2011, pp. 1–17.
Michini, B., Redding, J., Ure, N. K., Cutler, M., and How, J. P., “Design and Flight Testing of an Autonomous Variable-Pitch Quadrotor,” IEEE International Conference on Robotics and Automation (ICRA), 2011, pp. 2978–2979.