Altitude Control of a Single Degree of Freedom Flapping Wing Micro Air Vehicle (Postprint)

摘要

A control strategy is proposed for a minimally actuated flapping wing micro air vehicle. The Harvard RoboFly vehicle accomplished the first takeoff of an insect scale flapping wing aircraft. This flight demonstrated the capability of the aircraft to accelerate vertically while being constrained by guide-wires to avoid translation and rotation in the other five degrees of freedom. The present work proposes an altitude control scheme that would enable a similar vehicle under the same constraints to hover and track altitude commands. Using a blade element-based aerodynamic model and cycle averaging, it will be shown that altitude control of such an aircraft can be achieved. The RoboFly makes use of a single bimorph piezoelectric actuator that symmetrically varies the angular displacement of the left and right wings in the stroke plane. The wing angle-of-attack variation is passive and is a function of the instantaneous angular velocity of the wing in the stroke plane. The control law is designed to vary the frequency of the wing beat oscillations to control the longitudinal body-axis force which is used to achieve force equilibrium in hover and acceleration when tracking time-varying altitude commands.