An Electromagnetic Actuator for High-Frequency Flapping-Wing Microair Vehicles

An electromagnetic actuator weighing 2.6 g and operated up to resonant frequencies in excess of 70 Hz is presented with the intended application to flapping-wing MAVs. Comprised of a single electromagnetic coil, a permanent magnet rotor, and a “virtual spring” magnet pair, system resonance is achieved using a periodic excitation voltage applied to the coil, resulting in harmonic wing motion. Analytical models describing the electrodynamic interactions of system components and flapping-wing aerodynamic mechanisms are used to develop the equations governing the system's dynamics. Preliminary analysis based on simulation is used to build a working prototype from which further validation is conducted. Wing kinematics and mean lift measurements from the prototype demonstrated a lift-to-weight ratio of over one at 24 V. Based on a simplified equation of motion, approximate solutions for primary resonance mode and peak-to-peak (pk-pk) stroke amplitude were determined using the method of multiple time scales. Validated from frequency response experiments conducted on bioinspired test wings, these approximate solutions are used as a basis for an optimization framework. Finally, the developed framework is used to investigate the performance of the proposed actuator at different scales, predicting lift-to-weight ratios well above one for a wide range of the parameter space.