UC Irvine

Flapping wing micro-air-vehicles (FWMAV) are micro-air-vehicles that use biomimetic actuation (oscillatory flapping wing) for lift, propulsion, and control. The dynamic behavior of these bio-inspired systems is expressed by a multi-body, multi-time-scale, nonlinear, time-varying dynamical system model. This rich dynamic leads to unconventional stabilization mechanisms whose study essentially necessitates a mathematically rigorous analysis. Higher-order averaging, which is based on chronological calculus, can be utilized to show that insects and their man-made mimics (FWMAVs) exploit vibrational control to stabilize their body pitching angle. Such an unconventional stabilization cannot be proved by direct averaging. To experimentally demonstrate this phenomenon, an experimental setup was constructed. This setup allowed for two degrees of freedom for the body; vertical motion and pitching motion. It is found that there is a flapping frequency threshold beyond which the body pitching response is naturally (without feedback) stabilized, which conforms with the vibrational control concept. Moreover, a replica of the setup is fabricated with the FWMAV being replaced by a propeller revolving at a constant speed, which results in a constant aerodynamic force, leaving no room for vibrational control. The response of the propeller-setup is unstable at all frequencies, which also verifies the fact that the observed stabilization of the FWMAV-setup at high frequencies is due to vibrational stabilization.