Pitch dynamics and aerodynamic interactions in damselfly-Inspired micro air vehicles: the role of the position of the center-of-mass.

Abstract

This study investigates the influence of center-of-mass (CoM) positioning on the pitch dynamics of damselfly-inspired flapping-wing micro aerial vehicles. We develop a simulation framework that integrates computational fluid dynamics, rigid-body dynamics, and self-propulsion model. Using experimentally measured and fixed wing kinematics, we systematically examine how different CoM positions affect pitch attitude, aerodynamic moments, and flight velocity. The results reveal that variations in CoM position significantly influence body pitch motion, which in turn alters local flow conditions, vortex formation, and moment arm interactions. These changes give rise to a passive pitching mechanism that regulates pitch oscillations and prevents divergence over short timescales. This bounded behavior suggests that insects may achieve transient flight stability through passive aerodynamic-inertial coupling, even in the absence of active control. Additionally, a rearward CoM suppresses downward pitch motion and promotes ascent, while a forward CoM increases forward velocity but limits ascent capability. The findings demonstrate that transient stabilization and flight modulation can be achieved solely through mass distribution, offering a low-complexity design strategy for bio-inspired MAVs.