Modeling the Bio-Inspired Wing-Tail Interaction Mechanism and Applying It in Flapping Wing Aircraft Pitch Control

Birds produce tail control torques to maintain their attitude by unfolding their tails in the wing induced flow at hover. This mechanism is termed as wing-tail interaction. This study aims to apply this mechanism to the pitch control of a flapping wing aircraft. Momentum theory is adapted to analytically calculate the flapping wing induced flow and its distribution along the body is also presented. The proposed theory is experimentally tested on our self-designed flapping wing aircraft and it holds when the tail is installed within 1.5c (wing chord) distance from the leading edge at frequency above 10 Hz. The tail of our aircraft is mounted at the experimentally identified maximum tail control torque position to enlarge the control effect. An accurate tail control model of the aircraft is established with the validated theory and it is utilized to design frequency dependent tail controller. The controller can realize good pitch stabilization by including the flapping wing induced flow. The proposed theory can be easily incorporated into the tail controller design of flapping wing aircraft and has promising application potential in the similar tailed aircraft.