Abstract

In the field of micro-aerial vehicles (MAVs), simplicity of design is an important design characteristic. Simplicity in this context implies light weight, a prerequisite for flapping flight, and from a practical standpoint it aids in the manufacture and operation of the mechanism on such a small scale. However, simplicity comes at a price: as mechanisms are simplified they have fewer degrees of freedom, lower controllability, less power output. All of these will effect the ability of the mechanism to generate lift, but the losses can be minimized through proper design and implementation.

This thesis describes the design and fabrication of a flapping-wing MAV deriving inspiration from the biological mechanisms of a dragonfly. Dragonflies flap with an inclined stroke plane for hovering flight, which in conjunction with their two pairs of wings, presents an unexplored area of research for MAVs. Small changes in the hovering-flight wing kinematics create large simplifications in their mechanical reproduction. The MAV utilizes these simplifications while maintaining the most important characteristics of dragonfly hovering flight, including passive rotation of the wings, reliance on drag forces to generate lift, and the fluid interactions between adjacent wings flapping out-of-phase.

Two successive prototypes are presented, focusing on component design and fabrication techniques. These prototypes allow for easy modification of kinematic variables (phase shift between the fore-and hind-wings and factors that affect wing angle-of-attack) and component variables (most importantly, wing characteristics: size, shape, flexibility), important for future optimization. Initial experimental validation of the prototypes is presented.

To facilitate the experimental validation, a mechanical flapping wing mechanism has been designed and fabricated which is able to reproduce the high-stroke-plane kinematics utilized by dragonflies, an ability lacking in present flapping mechanisms. This flapping wing mechanism allows for the measurement of the instantaneous forces on a wing for a particular kinematics, by driving the wing with dynamically similar kinematics in a tank of oil. These experiments will be used in the future to analyze and optimize the lift generated by flapping-wing MAVs.