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Jesse Caldwell & Jon Schwank. Micromechanical Flight. MAE 268. Flight on micro level Types of Flight (MAV’s) Rotary Flapping MAV Aerodynamics Current Designs Future Applications Possible Improvements. Overview. Can flight be achieved on MEMS level? No self-contained MEMS flyers yet
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Jesse Caldwell & Jon Schwank Micromechanical Flight MAE 268
Flight on micro level • Types of Flight (MAV’s) • Rotary • Flapping • MAV Aerodynamics • Current Designs • Future Applications • Possible Improvements Overview
Can flight be achieved on MEMS level? • No self-contained MEMS flyers yet • 3 types of locomotion: • Classical airfoil, Re > 104 • Flapping flight,10<Re<104 • Drag-based, Re<10 Introduction
Flight at the micro level is distinctly different • Laminar flow, Re < 103 • Viscous forces dominate • Non-steady state locomotion • Boundary layer thickness ~ chord length Introduction
Conventional aerodynamics only accounts for ~30% of MAV lift • Increase in drag coefficient • Large decrease in lift to drag ratio • Flight is not possible with conventional aerodynamics alone Flight on micro level
Generating more lift: • Unsteady flapping or rotation – Can generate two additional lift mechanisms • Mimicking Insects • Extremely difficult to mimic Types of Flight (MAV’s) Typical insect wing stroke showing the wing tip location and angle of attack.
Three Lift Mechanisms • Conventional Aerodynamics • Leading Edge Vorticity (LEV) • Wake capture Insect Flight Lift
Can still harness all three MAV lift forces w/o mimicking insects • Blade-vortex interaction ~wake capture • LEV form on leading edge • Advantages to Rotary • Simple to control • Easy to fabricate • Disadvantages • Large surface beneath for MEMS Rotary Microflight
Implantation of MEMS into Insects Surveillance & intelligence Search & rescue Military Future Applications
Stacking comb drives • Relieves Surface Area • 2-3 Story Stack Up • Increases force 5 times Possible Improvements
Direct conversion to rotary motion • Low actuation voltage ~ 18-35 V • Easily Controlled (Square Wave) • Advantages • Generates large torques • Disadvantages • Failure at high speeds Torsional Ratcheting Actuater
Gear Train • Multiple gears to increase Torque or Speed • Convert high torque to high speed • Ideal solution for TRA Gearing
Flight on the Micro level • What works and What doesn’t • Looking to nature • Current Design • Future Ideas • Possible Improvements Conclusion