Gust Disturbance Rejection Study of a Cyclocopter Micro Air Vehicle

This paper describes the comprehensive wind tunnel studies conducted on a 550g cyclocopter micro air vehicle to determine its gust disturbance rejection capability and the development of a synthetic gust generation device capable of providing up to 4m/s step gust input for free flight experiments. The cyclocopter uses two cyclorotors with thrust vectoring capability, as well as a vertical thrusting nose rotor to counteract pitching moment produced by the cyclorotors. Planar gusts along the longitudinal and lateral axis of the cyclocopter were systematically studied. The response of the vehicle to these gust modes were evaluated in a succession of steps using 1-DOF pitch and roll gimbal stands and a 5-DOF setup (constrained only in lateral translation) in front of an open-jet wind tunnel. The cyclocopter uses differential rotational speed of the cyclorotors to counteract lateral gusts. To tolerate a gust perturbation along the longitudinal axis, the cyclocopter has capability to use either the pitching moment generated by the nose rotor or the propulsive force effected by vectoring the cyclorotors' thrust towards the freestream. Results from the 5-DOF experiments for the cyclocopter operating at 1400rpm showed that the thrust vectoring technique enabled the vehicle to tolerate up to 6m/s gust perturbation along the longitudinal axis compared to 2.5m/s when relying on pitch control. While the current 550g cyclocopter has demonstrated level forward flight up to 5m/s, it has the capability to achieve up to 6m/s.