Transcript MEMS Materials, Fabrication, & Applications

MICROMECHANICAL FLIGHT
Jesse Caldwell & Jon Schwank
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
4
airfoil, Re > 10
4
 Flapping flight,10<Re<10
 Drag-based, Re<10
INTRODUCTION

Flight at the micro level is distinctly different
 Laminar
3
flow, Re < 10
 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



Advantages to Rotary



Blade-vortex interaction
~wake capture
LEV form on leading edge
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?