Experimental studies of an inertial-elastic rotating wing in air and vacuum

Abstract

A two-axis rotation stage was constructed to replicate the large amplitude rotations of an insect wing. A wing was constructed with a strain gage mounted near the root to identify strain. An inertial-elastic model was used to predict temporal strain during various rotation trajectories. Single-axis rotations were considered, and multi-axis rotations were investigated to exploit phenomena related to geometric coupling. Experiments were conducted in air and in vacuum to decouple aerodynamic and inertial-elastic forces. It was found aerodynamic forces constitute maximally 15% of the strain, suggesting that an inertial-elastic model is appropriate in certain contexts. It was determined that inertial forces were dominant in the pitch-roll and roll-yaw configuration, whereas gyroscopic forces were dominant in the pitch-yaw configuration. Theoretic predictions match experimental results fairly well. The inertial-elastic rotating model may be used to inform flapping wing micro aerial vehicle designers moving forth, particularly in the design of strain-based control systems.