Jesse Caldwell & Jon Schwank

MICROMECHANICAL FLIGHT

MAE 268

OVERVIEW

Flight on micro level Types of Flight (MAV’s)

Rotary Flapping

MAV Aerodynamics Current Designs Future Applications Possible Improvements

INTRODUCTION

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

FLIGHT ON MICRO LEVEL

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

TYPES OF FLIGHT (MAV’S)

Generating more lift: Unsteady flapping or rotation

– Can generate two additional lift mechanisms Mimicking Insects Extremely difficult to mimic

Typical insect wing stroke showing the wing tip location and angle of attack.

INSECT FLIGHT

Three Lift Mechanisms Conventional Aerodynamics Leading Edge Vorticity (LEV) Wake capture

Lift

ROTARY MICROFLIGHT

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

CURRENT DESIGNS

FUTURE APPLICATIONS

Implantation of MEMS into Insects Surveillance & intelligence Search & rescue Military

POSSIBLE IMPROVEMENTS

Stacking comb drives Relieves Surface

Area 2-3 Story Stack Up Increases force 5

times

TORSIONAL RATCHETING ACTUATER

Direct conversion to rotary motion Low actuation voltage ~ 18-35 V Easily Controlled (Square Wave) Advantages

Generates large torques Disadvantages

Failure at high speeds

GEARING

Gear Train Multiple gears to increase

Torque or Speed Convert high torque to

high speed Ideal solution for TRA

CONCLUSION

Flight on the Micro level What works and

What doesn’t Looking to nature Current Design Future Ideas Possible

Improvements

QUESTIONS?