Date of Award

3-21-2013

Document Type

Thesis

Degree Name

Master of Science

Department

Department of Aeronautics and Astronautics

First Advisor

Richard G. Cobb, PhD.

Abstract

Piezoelectric bimorph actuators, as opposed to rotary electric motors, have been suggested as an actuation mechanism for flapping wing micro air vehicles (FWMAVs) because they exhibit favorable characteristics such as low weight, rapidly adaptable frequencies, lower acoustic signature, and controllable flapping amplitudes. Research at the Air Force Research Labs and the Air Force Institute of Technology has shown that by using one actuator per wing, up to five degrees of freedom are possible. However, due to the weight constraints on a FWMAV, the piezoelectric bimorph actuators need to be fully optimized to support free flight. This study focused on three areas of investigation in order to optimize the piezoelectric actuators: validating and improving analytical models that have been previously suggested for the performance of piezoelectric bimorph actuators; identifying the repeatability and reliability of current custom manufacturing techniques; and determining the failure criteria for piezoelectric actuators so that they can be driven at the highest possible voltage. Through the optimization, manufacturing, and performance testing of piezoelectric bimorphs, analytical models have been adjusted to fit the empirical data to yield minimum mass actuators that could potentially meet the mechanical energy requirements in a FWMAV. For custom manufactured actuators, optimized tapered actuators with an end extension showed an 89.5% energy density improvement over optimized rectangular actuators and a 19.5% improvement in energy density over commercially available actuators.

AFIT Designator

AFIT-ENY-13-M-21

DTIC Accession Number

ADA581757

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