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Micro Air Vehicles - Special Challenges
Jim McMichaelGeorgia Tech Research Institute
Presented to the DARPA Airplane on a Chip Workshop
Arlington, VA6/20/06
Micro Air Vehicles
Original Technical Objectives: Develop Flight Enabling Technologies Develop and Demonstrate Micro Air Vehicles Capable of
Sustained Flight and Useful Military Missions
MAV Definition: Small Air Vehicle No Larger Than
15 cm. in any dimension.
Fully Functional Vehicle Capable of Performing a Useful Military Mission at an Affordable Cost.
MAVS: A Prophecy Yet to be Fulfilled!
Why Micro? Local, On-Demand Situational Awareness Organic Asset, Eliminates Latency
Enables Completely New Missions Urban canyons, building interiors, ...
Vehicle weight - Trades with Water, Ammo, ... Eliminates Logistics Tail Affordable (Even Attritable) Hard to Detect Simple, Easy to Operate A DARPA-Hard Problem
MAV Provides “Over-the-Hill” Reconnaissance
• 15 cm, Fully functional military air vehicles
• Local situational awareness for small units
• Platoon level asset• Eliminates latency
• 30-60 minutes, 3-10 km• Day/night imaging
SimplicityLow cost
Soldier Proof
MAVs for Urban Operations
MAV HOST
MAV’s can deliverunattended
surface sensorsInterior Operationand Surveillance?Interior Operation?
Sensor Placement, Perching
Reconnaissance
See thru Windows
Bio-Chemical SensingChemical CloudTracked by MAV
Sensor detectsPPM - PPB
MAV Assisted Pilot RescueMAV provides situational awareness,
Provides beacon for rescue operations.
High Level Challenges• Low Re Aerodynamics and Control
• 15 cm MAV Re ~ 100,000
• Lightweight Power and Propulsion
• Navigation, guidance and control, autonomy, &communications
• Ultra-light structure, sensors and payloads
Speed
Hover
Agility
Covertness
High Degree of Integration and Multifunctionality
Range
State of the Art (‘96)Model Aircraft (>30 cm)• High Re Physics• High aspect ratio, high wing loading• Man-in-the-loop Radio Control
Model Airplane Engines ( .01 cu in)NiCd and Li Batteries• 300 mW/g• 350 J/g
Radio Control• GPS - (14 g, 3 W, )• Gyro - ( 28 g, .1 W, 1°/hr drift)• Comms. - (7 g, 1 W, 10 km)
Low Resolution Video • (380x540, 15g, 2watt)
MAV Technical Challenges
GoalsFixed Wing, Hover, Flapping (<15 cm)• Low Re Aero Performance• Low aspect ratio, low wing loading• Autonomous flight controls
Very Small ICEs (0.0035 cu in)Fuel Cells, Micro Turbine Engines
• 500 mw/g• 3,000 J/g, (30 g max)
Autopilot (15 g, 1.0 W)• GPS - (3 g, 0.2 W, )• Gyro - ( 3 g, .1 W, 0.1°/hr drift)• Comms. - (2 g, .5 W, 4Mb/s)
High Resolution, Low light• (1000x1000, 4:1 Compr., 3g, 0.2W),• IR Imager (<15g, <1W)
Enabling Technologies1. Aerodynamics, Stability
and Control
2. Ultra Lightweight Propulsion and Power
3. Guidance, Nav, and Comms
4. Sensors and Payloads
The Essence of the MAV Challenge
• Reduce Weight, volume, power required
• Increase complexity, reliability, functionality, utility ....... That can be put into a small, highly integrated package
“Original” (Natural) MAV Program Solved the Complexity Problem
Airframe & Materials
Unique Missions: Perch and Stare
Aerodynamics & Propulsion
Integration &Multifunctionality
10 g.10 cm wingspan3 min.Acoustic sensorsMEMS wings
Micro Air Vehicles
Caltech AeroVironment
Black WidowMicrobatLutronix
KolibriMicroSTAR
Lockheed Sanders
Stanford Research Institute
100 g.5 km range, 30 min.Autonomous Nav.Video imagery,Vmax ~40 m/sAvionics Pow ~ 2 WPayload ~ 4 g, 6 cm3
Mentor
320 g.30 min.Hover/translateGPSAutopilotVmax ~ 10 m/s Avionics Pow ~ 4 WPayload ~ 15 g, 95 cm3
50 g.Electrostrictive Polymer Artificial MuscleFlapping flightAvionics & Payload ~ 5 g
50 g.1 km rangeTeleoperatedVideo imageryVmax ~ 20 m/sAvionics Pow ~ 2WPayload ~ 2 g, 2 cm3
g % g % g %
Avionics 78 25 13.5 16 13 21
Power Systems 169 53 58 69 38 61
Airframe 54 17 9 11 9 14
Payload 15 5 4 4 2 4
Total 316 100 84.5 100 62 100
MAV Subsystem WeightSubsystem Weight and Mass Fraction
Power for MAVs
• Typical power for fixed wing 15 cm MAV (100g) is about 4 W for flight and 1-2W for avionics and comms
MAV Propulsive PowerComponent Size, Weight, and Power Requirements Must be Minimized
Maximize Endurance Parameter• Maximize Aerodynamic Perfromance• Thin cambered airfoils (low Re)
Minimize Altitude
Maximize Propeller Efficiency• Optimized size, speed & type may
not suit operational needs
Minimize Wing Loading• minimize wing loading• large wing area
- low aspect ratio
Minimize Weight• component synergy• microfabrication• reduce fuel load• maximize propulsion system energy density
• multifunctional materialsand components
CD3/2
WS
2ρPower to fly = W η
1/21/2
CL
MAV Propulsion and Power Options
TechsburgThermoelectrics
Projected 400 mw/g
IGR Solid Oxide Fuel Cell
M-DOTMini Turbine Engine
18 Watts 42 grams 4 hours 6200 J/g 430 mW/g
Aerodyne MICE
10 Watts 21 grams 1200 J/g 330 mW/g
( for 1 hour endurnace)
D-STARMini Diesel Engine20 Watts, 80 Watts
World’s smallest gas turbine1.5x3.25 in78 gm1.4 pounds of thrust1.27 KWJP8 - diesel
H2 Demonstration Micro-Engine
Thrust = 11 g
Fuel burn = 16 g/hr
Engine weight = 1 gram
Turbine inlet temp = 1600°K (2421°F)
Rotor speed = 1.2 x 106 RPM
Exhaust gas temp = 970°C
Silicon-Cooled Turbine
Need “Precision Microstructures”
Estimated Power Subsystem Options for 100 g Fixed Wing MAV
• Power System Requirements for 100g Fixed Wing MAV– Power system weight allocation is 60% vehicle weight, 60 g– 4 W peak available propulsive power, 3.3 W average– 5 W continuous conditioned electric power
• Endurance in hours for different power system combinations
Power System Combinations
Hou
rs
5432
1
SOFC/motor
5.4
MicroTurbojet/Turbogenerator
1.2
MicroTurbo-generator/motor
4.5
Triple ICE/Alternator
1.5
Diesel/Alternator
3.2
Cox-.01
0.6
E-PicherBattery
& Motor
0.2
MAV Payload VolumeCurrent MAV Systems Estimated Payload Bay Dimensions
Lutronix
1.9 cm height, 4.8 cm diameterVol = 95 cm3
Sanders
5 cm length, 1.1 cm height, widthVol = 6 cm3
1.2 cm cube, Vol = 2 cm3
AeroVironment
Need Increased Volume for Payload Sensors or Smaller, More Integrated, More Capable Avionics, Sensors and Processing
Data Link
Processor
Imager
Gyros
Rudder
Accelerometers
Engine
Con-troller
FlapActuators
FlapActuators
Nav/Positioning5 Grams
160 mW
3-AxisMagnetic
Pressure Sensor
Processor/Memory2.5 Grams600 mW
Camera/Lens4 Grams350 mW
Datalink/Antenna6.5 Grams2,000 mW
Airframe7 Grams
Batteries44.5 Grams
13 Watts AvailableAntenna
Power System
Actuators2 Grams200 mW
Engine/Prop13.5 Grams7,000 mW
Total System85 Grams
13 W
MicroSTAR Conceptual Layout (1996)
“Little big-airplane design paradigm” is followed in essentially all present MAV designs (2006)
1996 Autonomous Flight Control System Conceptual Layout for Kolibri
Avionics Assembly
3-Axis MCM-L Accelerometer
3-Axis MCM-LGyroscope
RF Communications/Proximity Sensor Electronics
GPS Module
Flex Backplane
Flight Control Computer
Battery
Power ModuleStabilator Cntrl
Image Sensor
Altimeter
Avionics FrameAcc
els
Gyr
osC
omm
s /P
roxi
mity
/ R
FG
PS /
FCC
Bat
tery
Pow
er
Avionics Top View
20 min endurance10-60 mphTurn radius = 15 ft.Span = 20cm
“With current COTS electronics, it is very difficult to carry any useful sensors or flight control system in a 14 cm MAV and still achieve decent duration.”
“When the Ground Control Station is added, the overall system sizes for a 15 cm and 60 cm MAV are about the same.”
MLB’s Trochoid MAV
Without increased multifunctionality and integrated components, the potential advantages of MAVs are not realized.
Black Widow1
AerovironmentWASP2 (41 cm) Aerovironment
University of Arizona4 University
of Florida6
University of Notre Dame5
MicroStar3
BAE Systems
Sample of Current “MAVs”
0
10
20
30
40
50
60
70
80
90
100
0 50 100 150 200 250 300
Span (cm)
ND
Pointer
Dragon Eye
OAVCyber Bug
MicroSTAR
WASP
Black Widow
Endurance Falls Rapidly as MAV Scale Decreases
Endurance Rises Rapidly as Weight Increases
Is There A “Size Asymptote for Utility” Without Higher Levels of Integrated
Multifunctionality?
20 cm Trochoid
MLB Company
OAV9
Honeywell
The “DARPA - Easy”* Problem
* “If you want more capability:Grow it bigger”
The DARPA-Hard problem is still to increase functionality at reduced scales through multifunctional integration
QuickTime™ and aVideo decompressor
are needed to see this picture.
‘Typical’ Rotary Wing MAV in Flight
QuickTime™ and aVideo decompressor
are needed to see this picture.
The views, opinions, and/or finding contained in this article are those of the author and should not be interpreted as representing the official policies, either expressed or implied, of the Defense Advanced Research Projects Agency or the Department of Defense
What Might Be Possible With Much Higher Levels of Integration & Embedded Functionality?
• Highly capable MAVs as a testbed for autonomous on-board decision making, both tactical and strategic– Develop revolutionary operator interface paradigms
• Intelligent, collaborative, self aware systems (air and ground sensors and vehicles)
• Real time SA advisor for operators in the field.
Return to the DARPA-Hard Challenge:- Truly Mission Capable MAVs
MEMS and Airplane on Chips
Amit LalProgram Manager, DARPA/MTO
Airplane-on-a-Chip Workshop, June 20-21, 2006
Outline
• Background on MEMS• AOC and MEMS• Insect on Airplane on Chip
MEMS?
• Micro • Electro• Mechanical• Systems
Lithography based , and perhaps self-assembled –not hand assembled
Electrical engineering –Integrated circuits, devices, circuits, multiphysics
Mechanics and fluidics of IC-fabricated structures –integration of mechanical with electrical –electromechanics
If only mechanical – the field is micromechanics
Systems: Means many thing to many people – the least well addressed vision of MEMS – but DARPA is at the forefront
Progression of MEMS
1950 1960 1970 1980 1990 2000
HNAAnodic Bonding
EDP
Pressure Sensor (Honeywell)
KOH
Si Pressure Sensor(Motorola)
Si as a mechanical material (Petersen)
SFB
SFB Pressure Sensor (NovaSensor)
TMAH
DRIE !!
XeF2/BrF3
Metal sacrificial process (US Patent)
RGT (Nathanson et al)
Metal Light Valve (RCA)
PolySi beams (Howe, Muller)
PolySi Micromotor (Tai, Muller) IR imager (Honeywell)
PolySi Comb Drive (Tang, Howe)
ADXL AccelerometerDMD (TI)
Si Gyro (Draper)LIGA
IC
RF MEMSBio MEMS
CSAC, NGIMG
Fabrication plus basic sensors
Surface micromachined sensors
2010
MicroElectroMechanicalSystems
CMOS microelectronics,
RF
III-V compound
semiconductor
Nanotubes, QDs
RadioactivityGas/vaccum
devices
Nanofabrication
CryoelectronicsMicrofluidics MEMS
MEMS Electrostatic Actuators
Suspended structure
Example: MEMS Automotive Sensors
G= Gyro
A= Acceleration
•L=Low (<5g)
•M=Medium (50g)
•H=High (>100g)
Airbag DeviceNon-Airbag Device
AH (Z or X)
airbag
airbag
airbag
alarmAL (XY)
airbagGY
GZ
GZ
AL (Z)
rolloverAL (ZY)
VDCAL (XY)
GPS/NavAL (XY)
AM (Z or X)
AM (Z or X)
AM (XY)
•Small proof mass enables fast response enabling side impact bags•Small size enables low power operation•Small size enables high thermal isolation and budgets•Small size enables high resonant frequencies
MEMS and Transistors
Historic MEMS Devices
Future MEMS Integration Levels Enabled Applications
Increasing Ability to Sense and Act
Incr
easi
ng A
bilit
y to
Com
pute
100
101
102
103
104
105
106
107
108
109
101 102 103 104 105 106 107 108 109
Number of Mechanical Components
Optical Switches and Aligners
Parts Handling
Integrated Fluidic Systems
Physiological Sensors
Inertial Navigation on a Chip
Terabits/cm2
Data Storage
Ultrasonic Imagers
Displays
RF Switching, Wireless
Distributed Structural Control
Num
ber
of T
rans
isto
rs
Cars, Consumers
Micromachining: Users viewpoint
• Technology to make microscale mechanical parts integrated with electronics
• Another machining technology, like mill and lathe• Mill and lathe were really exciting when they first
came out - now we take them for granted• DARPA MEMS Exchange is a program for users!• Various MEMS foundries also serve this purpose
Micromachining: Integrated Circuits Viewpoint
• Micromachining is a bag-of-tricks on top of the conventional IC-fabrication facility
• Lithography is used to generate microscale mechanical features
• Development in finer resolution lithography means smaller mechanical machines (e.g. DUV lithography)
• MEMS is usually “dirty” for ultraclean circuit fabs
MEMS is like Spanish moss on
the IC industry tree
The New Paradigm Viewpoint
• Micromachining enables a new way of thinking about mechanical structures
• Parallel (huge) arrays of machines are possible
• Machines comparable to size of biological objects are possible
• Integration of electromechanical machines to individual small scale objects is possible
AOC and Selected MTO MEMS
Cs or Cs or RbRbGlassGlassDetectorDetector
VCSELVCSEL
SubstrateSubstrate
GHzGHzResonatorResonatorin Vacuumin Vacuum
PhotoDetector
VolVol: 1 cm: 1 cm33
Power: 30 Power: 30 mWmWStab: Stab: 11××1010––1111
Chip-ScaleAtomic ClockCSAC
Atomic Sensors
Flight Control
NGIMGZ
YX
HERMIT
Micro Flaps
3D MERFS
ASP
MIT μturbine
μfluidic fuel injector
μcombustion
µWankelMCC
MGA
Atomic Clock Principle & Design
• Problem: µwave cavity dictates size133Cs
m = 0f = 4
m = 0f = 3
m = 1
852.11 nm
852.11 nm
ν = ∆E/ħ = 9 192 631 770 Hz
9 192 631 770 Hz
133Cs vapor at 10–7 torr852.11 nm laser
Photodetector
µ-wave cavity
Microwave at9 192 631 770 Hz
Optical-Microwave Atomic Clock
µ-wave f
852.11 nm laserModulated at
9 192 631 770 HzPhoto
detector133Cs vapor at 10–7 torr
Mod f
All-Optical Atomic Clock• Solution: optical excitation (CPT)
• Frequency determined by an atomic transition energy
InterrogatingLaser
Absorption
HyperfineTransition
Input Energy
Chip-Scale Atomic Clock (CSAC)PM: Amit Lal
Goal:• Integrate MEMS, photonic, and electronics
technologies to achieve miniature, low-power atomic timing and frequency references with
– Allan deviation < 10-11 over 1 hour (1µs/day)– Size <1 cc– Power Consumption < 30 mW
Technical Challenges:• Cell design for maximum Q• GHz high-Q reference resonator• MEMS-enabled thermal isolation for low powerKey Accomplishments:• Chip-scale atomic physics package demonstrated
with ~5 mW of power consumption• GHz vibrating micromechanical resonators
demonstrated• Chip-scale atomic clock with 5x10-11 Allan deviation
at 1 sec, in a 10cc package, consuming 180 mWImpact:• High-security communications• High-confidence ID of friends and foes• Ultra-sensitive radar• Missile and munitions guidance• Longer autonomy (radio silence interval)• Tech Transfer Path: Air Force, JTRS
communications, Army, numerous others in GPS
3.53
cm
Physics Package
3.94 cm Physics Package
Precision Time for Every Radio and Network Node
0.0001 0.001 0.01 0.1 1.0 10.0 100.0 1000.0
0.0001
0.001
0.01
0.1
1.0
Bias Drift [o/hr]
Rate Grade
Tactical Grade
Navigation Grade
Ang
le R
ando
m W
alk
[o/√
hr]
Gyroscope Requirements
Rate Grade
Analog ADXRS401ARW: 3.8 o/√hr
Bias Stability: 50 o/hrFull Scale: ± 75 o/s
Power: 30 mWSize: 0.15 cc
Honeywell HG1900ARW: 0.05 o/√hr
Bias Stability: 5-12 o/hrFull Scale: ± 1,000 o/s
Power: 1.95 WSize: 283 cc
Litton HRGARW: 0.00006 o/√hr
Bias Stability: 0.0003 o/hrFull Scale: ± 4 o/s
Power: 22 WSize: 8,118 cc
Nuclear Magnetic Res. Gyroscope
• The ultimate in miniaturized spinning gyroscopes?– from CSAC, we may now have the technology to do this
Atoms AlignedNuclear Spins
0º
-20º
20º
0º
-20º
20º
LaserPolarizer
Rb/Xe Cell
Photodiode
3.2 mm
1 mm
1 mmtθ
Soln: Spin polarize Xe129 nuclei by first polarizing e- of Rb87 (a la
CSAC), then allowing spin exchange
Better if this is a noble gas nucleus (rather than e-), since nuclei are
heavier less susceptible to B field
Challenge: suppressing the effects of B field
ARW ~ 0.0006 o/√hr
Nav-Grade Integrated Micro Gyroscopes (NGIMG)
PM: Amit LalGoal:• Attain tiny gyros and accelerometers with
navigation-grade performance and tiny power consumption
Technical Challenges:• Reducing magnetic field sensitivity for NMR
gyros• Attaining high spin rate for levitated gyros• High Q optical resonatorsKey Accomplishments:• Ultrahigh 106 Q quartz resonators
demonstrated for class 2 gyro• 50 rpm rotating and electrostatically levitated
spinning mass demonstrated• Nav-grade performance in NMR gyro on an
optical bench demonstrated using B-field nulling
Impact:• Enable wearable, low power IMU modules for
dismounted soldier• Guidance for munitions, UAVs, and insect-like
robotics platforms• Tech Transfer Path: Air Force, JTRS
communications, Army, numerous others in GPS
X
Z
YRotor 1
Rotor 2
RPM ~133
Harsh Environment Robust Micromechanical Technologies (HERMIT)
PM: Amit Lal
Goal:• Attain superior performance and lifetime of MEMS devices
via localized control of their operating environments• Achieve upwards of a 10x improvement in cycle lifetime for
RF-MEMS switches, and temperature stability for resonators & gyros
Technical Challenges:• Wafer-level vacuum packaging of micro-scale devices• Chip-scale control of environment, including: pressure,
temperature, vibration, and gaseous speciesKey Accomplishments:• Wafer-level packaged RF MEMS switch demo’d with 0.02dB
loss @ 35GHz and > 1 billions cycles• CVD-based vacuum packages demonstrated with no
observable leakage over 6 months• Packaged resonator freq. drifts <2 ppm over 6 months• Much higher (95%) yields observed for wafer-level
packaged micromechanical resonatorsImpact:• Enable small, low-power, true-time delay units for phased
array antennas, reconfigurable filters, and low-phase noise oscillators for radar and communications
• Enable guided munitions and self-navigating micro-air vehicles
• Tech Transfer Path: Army, Air Force, DoD T&E
Realizing the Promise of MEMS through Wafer Level Packaging
Robust Capacitive MEM Switches
CVD CageStructure
OpenVA
Tri-StateLogic
Seal via combination of spin-on-glass
(SOG) and nitride
Seal via combination of spin-on-glass
(SOG) and nitride
Package Insertion Loss - Cages + SOG
-0.5
-0.45
-0.4
-0.35
-0.3
-0.25
-0.2
-0.15
-0.1
-0.05
0
0 5 10 15 20 25 30 35 40 45 50Frequency (GHz)
Inse
rtio
n Lo
ss (
dB)
Thru1Thru2514B1cs514B2cs514B3cs514S1cs514S2cs514T1cs
0 10 20 30 40 50Frequency [GHz]
Inse
rtio
n Lo
ss [d
B]
0
-0.1
-0.2
-0.3
-0.4
-0.5
Thru Line
Package (Cage + Encapsulant)
The HERMIT Concept and Impact
Gap ~120 nm
UNCD
Stanford – Embedded resonators - timing
Michigan - Gyroscopes
UCB–SiC Strain Sensors, T up to 600°C
Honeywell – Liquid Metal, High Power
Northeastern – High Force Ohmic
Memtronics – Capacitive
UCSB – Ti-MEMS
Argonne – CMOS Compatible Diamond MEMS
Resonators/Sensors
Switches
Radant
Micro Gas Analyzers (MGA)PM: Dennis Polla
Goal:• Enable remote detection of chemical agents via
tiny, ultra-low power, fast, high sensitivity, chip-scale gas analyzers with low incidence of false positives..
Technical Challenges:• Rapid chemical separations (GC).• New detectors (mass spectrometers, chemi-
resistors, Nanotube detectors).• Sensitivity < 50 ppt• False alarm rate < 1/200,000 measurements.
Key Accomplishments:• Preconcentrations of DMMP >8,000• Separation of 4 CW simulants in the presence of
4 hyrdocarbon interferrents• 1 Torr operation of a 1-mm ion trap mass
spectrometer with 2.3 amu resolutionImpact:
• Deployment of highly sensitive analytical instruments in the field with a low incidence of false-positive detections
PO
O OCF3
CF3
OH
Si
Si
O
Si
O
SiO
Si
O
Si
O
Si
OO
Si
O
Si
Si
O
OSi Si
OSi
OSi
OSi
O
SiO
O
Si
O
Si
O
Si O
SiO
O CF3
F3COCF3
F3C
O
O
OP
H
OO
OP
H
Hydrophobic CF3 groups
Strong hydrogenbonding interactions
Absorbent covalentlybonded to silica matrix
Micromachinedchromatography
columns
Chemical detectors
Ion Mobility Mass Spec
Chemicalpreconcentration
micro/nanostructures
Chemicalfunctionalization ofsorptive molecules
Gold Standard Chemical Gas Analyzer in a Match Box
Micro Cryogenic Cooler (MCC)PM: Dennis Polla
Goal:• Attain superior performance (e.g. , of LNA, RF front
ends, sensors, …) by cooling to cryogenic temperatures
• Power consumption <200mW• DTBC in isolation with >10x perf. increase• Ex: COP: >0.01 @77K, >0.04 @160K• Size < 4cc
Technical Challenges:• Active or passive circuits on micromachined
platforms• Micromachined compressors, heat exchangers, high
pressure• Thermoelectric cooling, laser cooling, Joule-
ThompsonKey Accomplishments:• Proven gettered vacuum packaging methodology
directed self-assembled wafer-level fab allows the use of an unconstrained variety of TE’s
• Tiny diameter photonic crystal heat exchanger tubes→25atm
• Heat exchangers supported by thermally isolating SU-8 rods
• Piezoelectric compressors → 25:1 pressure dropImpact:• Imaging at terahertz frequencies (defined roughly as
300GHz-3THz)• Increase application performance of IR detectors,
low noise amplifiers and data converters, electromechanical oscillators, and high temperature superconductor circuits
3.94 cm
Images of 3-D MERFS Structures (5 lithographic layers, 3 Material)
PM: John Evans
1 mm1 mm
Dielectric Strap
Center copper conductor
Outer copper conductor
Hybrid Coupler
Isolation test structures
Attenuation Test Structure Cavity Resonator
“Launch” De-imbedding Test Structures 6-Inch 3-D MERFS Wafer on RF Probe Station
λ/4 matched flexure tether
Drive and Sense electrodes
30 nmHafnium Dioxide
Silicon
λ/4 matched flexure tether
Drive and Sense electrodes
30 nmHafnium Dioxide
Silicon
ASPPM: John Evans
ADCIF Chain
IF Chain
IF Chain
IF Chain
IF Chain
RF FilterBank20 MHz –
6 GHz
25 MHz BW
25 MHz BW
25 MHz BW
25 MHz BW
25 MHz BW
25 MHz BW
25 MHz BW
25 MHz BW
25 MHz BW
25 MHz BW
25 MHz BW
25 MHz BW
70 MHz IF
20 MHz –6 GHz
Analog Sensor
5 GHz/s requires 5 ms per 25 MHz block.
5 ms / 100 us sample periods
50 sample periods per 25 MHz block
IF Chain
ADC
ADC
ADC
ADC
IF Filter
IF Filter
IF Filter
IF Filter
IF Filter
Distribution Statement “A” (Approved for Public Release, Distribution Unlimited), DARPA Case 6709, 2/15/06
MEMS wing boundary layer modification
Typical flow over a delta wing at moderate angles of attack
MEMS shear stress sensonr and shear stress “imager”
Ho et al. (UCLA)
Micromachined sensors and actuators could
provide sufficient moments/torques to replace large flaps in aerodynamic control
Mico flap actuator under activation
1st generation flexible shear stress sensor
2nd generation flexible shear stress sensor
Small disturbances caused by microactuators at appropriate locations could cause appreciable changes in the
global flow field
Insect-on-Chip
WASP-DARPA, 200 grams, 12-inch wing span, 1-2 hr fly time
Caltech flyer
UC Berkeley Flyer
Nano - Air Vehicle Program
•20-30 minute mission•7-cm wingspan•Controlled hover and landing
Insect locomotion is used as model for these efforts
Why not use insects directly?Bee training, insect backpacks -> Insects too unpredictable (temperature, wind, humidity,
mating, feeding, etc.)Insight: Eliminate unnecessary biology using
MEMS
Insect Cyborgs
Normal growth
DARPA Program : Use object
insertion ability into pupas to reliably
insert microsystems
(instead of glass tube) for insect
control
Pupa halved and front develops into
moth
Sectioned Pupa with pipe inserted for hormone transport – grows into moth shown above. Insertion of
chemical blocking ball bearing results in no growth
Platform with Silicon Chips
Balsa platforms were stitched in the pupae stage
Moth emerges with platform and flies for 2 weeks
•We have proven successful platform insertion in pupa stage, without effecting flight, or lifetime•Ready for locomotion control payloads!
Hybrid-INSECT MEMS
Ultrasonic transducers
Pheromone ejectors
Light sources
Piezoelectric flaps for power
Thermoelectric power, flexible
platform
Cross and across inserts in pupae
Platform for sensors, actuators, and comm
NGIMG
CSAC
•Moth body weight ~1-5 grams•Payload ~ 0.5-5 grams
Microfluidic port
Tissue-anchors
Neural/Muscleprobes
Summary
• MEMS offers pathways to miniaturized and chip-scale sensor and actuator systems to reduce size of AOC components
• Upcoming MEMS/CMOS integrated solutions will enable cost reduction of AOC systems
• Integration of MEMS with nature (e.g. insects) could provide methods to realize cyborgs that might require unique AOC capabilities
QUESTIONS?
Amit Lal, DARPA-MTO1
Microsystems, Scaling, and Integration
Amit Lal, Program ManagerMTO/DARPA
Microsystems Technology SymposiumSan Jose, CA, March 6, 2007
Report Documentation Page Form ApprovedOMB No. 0704-0188
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4. TITLE AND SUBTITLE Microsystems, Scaling, and Integration
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13. SUPPLEMENTARY NOTES DARPA Microsystems Technology Symposium held in San Jose, California on March 5-7, 2007.Presentations, The original document contains color images.
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Standard Form 298 (Rev. 8-98) Prescribed by ANSI Std Z39-18
Amit Lal, DARPA-MTO2
Progression of MEMS
NEMS-CMOS: Meshing of transistors and relays
Hybrid-Insect MEMS
Integrated RF-SYSTEMS - RADAR
Chips-Scale Atomic Clock
1950 1960 1970 1980 1990 2000
HNAAnodic Bonding
EDP
Pressure Sensor (Honeywell)
KOH
Si Pressure Sensor(Motorola)
Si as a mechanical material (Petersen)
SFB
SFB Pressure Sensor (NovaSensor)
TMAH
DRIE !!
XeF2/BrF3
Metal sacrificial process (US Patent)
RGT (Nathanson et al)
Metal Light Valve (RCA)
PolySi beams (Howe, Muller)
PolySi Micromotor(Tai, Muller) IR imager (Honeywell)
PolySi Comb Drive (Tang, Howe)
ADXL AccelerometerDMD (TI)
Si Gyro (Draper)LIGA
IC
RF MEMSBio MEMS
2010
MicroElectroMechanicalSystems
Amit Lal, DARPA-MTO3
Two views of MEMS
MEMS is like Spanish moss on the IC industry
tree
http://www.mems-exchange.org
MEMS for everyone/everything?
Amit Lal, DARPA-MTO4
MEMS for Microsystems
• Miniaturization/Integration – SWAP• Scaling for higher performance• Multiphysics• Biological interfaces• Gateways to nanoscale effects• Environmental control over sensors and
actuators
Temex RMOVol: 230 cm3
Power: 10 WAcc: 1×10–11
Symmetricom CSACVol: 7.8 cm3
Power: 95 mWStab: 5×10–11/100s
100 µm
Drain Source
Gate
Contact Detail
Beam
RF-MEMS switch
Integration of Alkali-metal
vapor on chip for atomic sensors
Embedded MEMS - HERMIT
Universal MEMS package-HERMIT
0.8 cm
Navigation grade Gyroscope
Insect MEMS
CSAC
NEMS - switch
Amit Lal, DARPA-MTO5
Radant Demonstrates>900 Billion Switch Cycles
Wins Frost & Sullivan Excellence in Technology Award
Tri-Service DoDTesting Team
MEMS:Undeniable Reliability
PM: Amit Lal, HERMIT
Demo Radar
0.4 m2 Azimuth Scanning MEMS RadantTM Lens
Composite Frame (Graphite / Epoxy)
APG-67Xmtr
Lockheed Martin Modified APG-67 Radar Components APG-67
ProcessorFeed
ControlLens Ctrl/Interface
APG-67RF
Ctrl / Interface
New / Modified HW/SW
Modified Hardware
30 degree scan 0.4m2 ESA
MEMS Insertion into the RadantTM
Lens Architecture has Been Demonstrated
This Antenna is the First Large Scale Use of MEMS Switches in the World
MEMS Insertion into the RadantTM
Lens Architecture has Been Demonstrated
This Antenna is the First Large Scale Use of MEMS Switches in the World
Amit Lal, DARPA-MTO6
Hybrid-Insect MEMSVISIONVISION
OBJECTIVESOBJECTIVES• Develop technology to enable highly coupled electro
mechanical interfaces to insect anatomy • Demonstrate MEMS platforms for electronic locomotion
control, power harvesting from insect, and eliminate extraneous biological functions
Create technology to reliably integrate microsystems payloads
on insects to enable insect cyborgs
Amit Lal, DARPA-MTO7
Background: Insect Metamorphosis
1st instar 2nd instar 5th instar4th instar3rd instar
Storage of energy over weeks to use later for flight
Amit Lal, DARPA-MTO8
Key Experiments in 1940s
Normal growth
DARPA Program : Use object
insertion ability into pupas to reliably
insert microsystems
(instead of glass tube) for insect
control
Pupa halved and front develops into
moth
Sectioned Pupa with pipe inserted for hormone transport – grows into moth shown above. Insertion of
chemical blocking ball bearing results in no growth
Amit Lal, DARPA-MTO9
MEMS PlatformUltrasonic
transducers
Pheromone ejectors
Light sources
Piezoelectric flaps for power
Thermoelectric power, flexible
platform
Cross and across inserts in pupae
Platform for sensors, actuators, and comm
NGIMG
CSAC
•Moth body weight ~1-5 grams•Payload ~ 0.5-5 grams
Microfluidicport
Tissue-anchors
Neural/Muscleprobes
Amit Lal, DARPA-MTO10
HI-MEMSHybrid Insect MEMS
PM: Amit Lal
Microsystem platform inserted into moth in pupae stage, and successful emergence of adult moth
with microsystem
X-ray images of probes in muscles show good tissue
growth around inserted probes
Boyce Thompson Institute:Insect Sentinals
Amit Lal, DARPA-MTO11
Hybrid NEMS ElectronicsRelay computer
(circa 1950)
Pentium (2006)
NEMS/CMOS
Abacus Babbage
4004 (1971)
8086 (1978)
+
Amit Lal, DARPA-MTO12
Hybrid NEMtronicsObjectivesObjectives
• Eliminate leakage power in electronics to enable longer battery life and lower power required for computing.
• Enable high temperature computing for Carnot efficient computers and eliminate need for cooling
ApproachesApproaches• Use NEMS switches with and
without transistors to reduce leakage – Ion:Transistor, Ioff: NEMS
• NEMS can work at high temperature, enabling high efficiency power scavenging.
N+ N+ P+ P+
N-WellP-Substrate
VDDOUT
GND ININ
All Mechanical Computing
Hybrid NEMS/CMOS component integration
Hybrid NEMS/CMOS Device integration
1
1
0
0
1
0
01
Ion
Ioff
Amit Lal, DARPA-MTO13
Nano Switches
Released FinFET NEMS switch
Nanotube/Fiber switches
Nano-machined switches
50 nm tines
CMOS Integrated NEMS
40 nm beam
Nanoscale e-
shuttle
1 µm in 0.35µm,
100nm in 90 nm CMOS
Amit Lal, DARPA-MTO14
The Problems: Max Heat Removal Rate and Leakage Power
Lg/VDD/VT trends increases in:• Active Power Density (∝VDD
2) ~1.3X/generation• Passive Power Density (∝VDD) ~3X/generation
Excessive Heat Generation
NEMS
1E-05
1E-04
1E-03
1E-02
1E-01
1E+00
1E+01
1E+02
1E+03
0.01 0.1 1Gate Length (µm)
Pow
er (W
/cm
2 )
Passive Power Density
Active Power Density
Excessive Ioff
NEMS can eliminate
leakage current –
Zero-idle
powerNEMS can work at high
temperatures: Carnot
efficient computing
Amit Lal, DARPA-MTO15
The Carnot Optimized Computer
PextSi
+
Pconv
TH
TC
)1(H
CHGinin
H
CHGinext T
TTPPT
TTPP −−=
−−= ηη
• TH should be maximized for high Carnot efficiency• 700C => 973-300/973 = 0.70 • If 50% of Carnot => 35% power can be reclaimed• Cooling could be eliminated• Needs fast switching technology at high temp – NEMS
PinPremove
Past Example
Amit Lal, DARPA-MTO16
Self-calibrating Micro Sensors: Shoe-Implanted Perpetual Personal Navigation
CMOS-MEMS Micro 3-axis accelerometer/gyro possible but have offsets due to imprecise fab. Develop ppmaccurate sensor model using on-chip calibration techniques – eliminate temp control to reduce power
Sonic pulsing, fluid MEMS to sense velocity directly
Precision and stable resonators provide frequency for self-calibration
Power scavenging from motion in shoe ~ 10 milliWattaverage over mission
HI-MEMS insect power output >5 milliWatt average
1 cc, 5-mW average
IMU
State-of-Art (without electronics or GPS) IMU: 14cc, 250 mW
10x reduction in size, >100x reduction in power
Amit Lal, DARPA-MTO17
MTO Mostly-silicon UAV
rece
iver
trans
mitt
er
IR se
nsor
acou
stic
sens
or
optic
al se
nsor
RF se
nsor
CB se
nsor
sens
ors
ante
nnae
sigpr
oces
s
fligh
t con
tr
iner
tial n
av
rece
iver
trans
mitt
er
rece
iver
trans
mitt
er
IR se
nsor
acou
stic
sens
or
optic
al se
nsor
RF se
nsor
CB se
nsor
IR se
nsor
acou
stic
sens
or
optic
al se
nsor
RF se
nsor
CB se
nsor
sens
ors
ante
nnae
sens
ors
ante
nnae
sigpr
oces
s
fligh
t con
tr
iner
tial n
av
sigpr
oces
s
fligh
t con
tr
iner
tial n
av
Distributed actuators to pump air + solar cells +
batteries
Control Electronics
Amit Lal, DARPA-MTO18
Benefits of mostly-silicon MAV
Functionality – Entropy – Data Bandwidth
Wei
ght (
a.u.
) Power (a.u.)
Inertial sense guidance
RADAR
IR imaging
Collision avoidance
No-wiring, limited packaging
Low-power CMOS, MEMS components to reduce power for RF
Amit Lal, DARPA-MTO19
CMOS microelectronics,
RF
Nanoelectronics
Quantum computation
RadioactivityGas/vacuum
devices
Avionics
Cryo-electronicsMicrofluidics MEMS
Amit Lal, DARPA-MTO20
Summary• MEMS offers pathways to miniaturized
and chip-scale sensor and actuator systems for reduced SWAP and increased functionality
• Upcoming MEMS will result in cost/performance benefits by integrating functionality
• The future for MEMS-IC symbiosis is bright
Amit Lal, DARPA-MTO21
QUESTIONS?
MEMS BASED BIOELECTRONIC NEUROMUSCULAR INTERFACES
FOR INSECT CYBORG FLIGHT CONTROL A. Bozkurt1, R. Gilmour2, D. Stern3, A. Lal1
1Cornell University, School of Electrical and Computer Engineering, Ithaca, NY 14853 2Cornell University, Department of Biomedical Sciences, Ithaca, NY 14853
3Boyce Thompson Institute, Ithaca, NY 14853
ABSTRACT
This paper reports the first direct control of insect flight by manipulating the wing motion via microprobes and electronics introduced through the Early Metamorphosis Insertion Technology (EMIT). EMIT is a novel hybrid biology pathway for autonomous centimeter-scale robots that forms intimate electronic-tissue interfaces by placing electronics in the pupal stage of insect metamorphosis. Our new technology may enable insect cyborgs by realizing a reliable control interface between inserted microsystems and insect physiology. The design rules on the flexibility of the inserted microsystem and the investigation towards tissue-microprobe biological and electrical compatibility are also presented.
1. INTRODUCTION
When Micro-Air-Vehicles (MAVs) or tiny fliers are considered, the power source required to fly them within the constraint of generating lift, powering flight control sensors and actuators, and collision avoidance has limited their mission time and autonomy. Researchers have greatly benefited from the study of naturally occurring fliers to design individual biomimetic structures as the parts of MAVs [1]. Although, a tremendous effort has been put forth to combine these structures as a complete MAV, there has been no successful demonstration of a system that can takeoff, maneuver and land autonomously for long periods of hours or days [2].
Another idea has been to directly use naturally designed and optimized flyers, namely, insects as MAVs [3-5]. Insects are self-powered, are cm-scaled and operate with highly efficient flight muscle actuators. Man-made electronic systems can be implanted in insects to study and control the insect flight by recording from and actuating either each or combinations of the sensory, neural or muscular systems. However, it is a challenge to implant electronic systems to modulate the insect’s flight without disturbing the insect’s own efficient flight mechanism. Any artificially attached platform and surgery on the adult insect is not reliable, as the inserted devices on this stage can shift, create mass-balance disturbance and cause performance affecting tissue damage, especially when the inserted electronic systems are rigid.
In our previous work [6], we demonstrated an efficient method to implant structures in tobacco hawkmoth Manduca sexta, which we call “Early Metamorphosis Insertion Technology” (EMIT). EMIT involves inserting structures to the pupae at early stages of metamorphosis (Figure 1) such that the body adapts the structures during the development and inserted structures emerge as a part of the body to create insect cyborgs. A reliable biointerface was created by taking the advantage of the rebuilding of the entire tissue system. This hybrid structure enables a platform where CMOS devices and MEMS structures can be used as sensors and actuators not only for insect flight control, but also for biological and environmental sensing. Moreover, this platform can be used to study the probe-tissue interface in general for MEMS based neuromuscular prosthetic systems.
EMIT can benefit from any insect/animal that has metamorphic development (moths, butterflies, beetles, etc.) to create insect cyborgs with different locomotion capabilities. We have selected Manduca sexta due to its relatively shorter metamorphic duration of three weeks. With its 1-2 gram carrying capacity, flight range of miles, wingspan of 10cm and lifetime of 2-3 weeks, Manduca sexta makes a wide range of applications for these devices possible.
Figure 1: The life-span of Manduca sexta during the metamorphic development and the results of insertions done at various stages of metamorphosis.
Report Documentation Page Form ApprovedOMB No. 0704-0188
Public reporting burden for the collection of information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sources, gathering andmaintaining the data needed, and completing and reviewing the collection of information. Send comments regarding this burden estimate or any other aspect of this collection of information,including suggestions for reducing this burden, to Washington Headquarters Services, Directorate for Information Operations and Reports, 1215 Jefferson Davis Highway, Suite 1204, ArlingtonVA 22202-4302. Respondents should be aware that notwithstanding any other provision of law, no person shall be subject to a penalty for failing to comply with a collection of information if itdoes not display a currently valid OMB control number.
1. REPORT DATE JAN 2008 2. REPORT TYPE
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4. TITLE AND SUBTITLE MEMS Based Bioelectronic Neuromuscular Interfaces for Insect CyborgFlight Control
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7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) Cornell University,School of Electrical and Computer Engineering ,Ithaca,NY,14853
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12. DISTRIBUTION/AVAILABILITY STATEMENT Approved for public release; distribution unlimited
13. SUPPLEMENTARY NOTES 21st IEEE International Conference on Micro Electro Mechanical Systems (MEMS 2008), Tucson, AZ,January 2008, pp. 160-163
14. ABSTRACT This paper reports the first direct control of insect flight by manipulating the wing motion via microprobesand electronics introduced through the Early Metamorphosis Insertion Technology (EMIT). EMIT is anovel hybrid biology pathway for autonomous centimeter-scale robots that forms intimate electronic-tissueinterfaces by placing electronics in the pupal stage of insect metamorphosis. Our new technology mayenable insect cyborgs by realizing a reliable control interface between inserted microsystems and insectphysiology. The design rules on the flexibility of the inserted microsystem and the investigation towardstissue-microprobe biological and electrical compatibility are also presented.
15. SUBJECT TERMS
16. SECURITY CLASSIFICATION OF: 17. LIMITATION OF ABSTRACT Same as
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Standard Form 298 (Rev. 8-98) Prescribed by ANSI Std Z39-18
2. EXPERIMENTAL PROCEDURE AND RESULTS Microprobe Design
In the case of flight muscle actuation, the main flight powering muscles are located in the dorsal-thorax of the Manduca sexta (Figure 2) where electronic implants can be located. The dorsovental and dorsolongitudinal muscle groups move the wings by changing the conformation of the thorax, which supplies the mechanical power for up- and downstrokes. The alternating relaxation and contraction of these muscles create the alternating up- and down-strokes hence the flight. Therefore, the designed probe should target actuating these muscle groups.
Probe flexibility is a required design property for wider probe geometries, since the probe has the potential to affect the biomechanics of muscle contraction. Conversely, muscle contraction can cause impact and high strain damage to the probe. We had previously demonstrated a microsystem with all-silicon probes [7]. Here, polyimide was selected as the base material of the probe due to its flexibility and biocompatibility. Moreover, fragility and delicacy of the probes while handling during the insertion and throughout the experiments is less of a concern with a flexible polyimide probe. The aimed experimental protocols consist of tethered setups where insect flight muscle is actuated through the flexible wires, as well as non-tethered setups where there are no attached wires and free-flight of insect can be realized. We designed and manufactured a flexible probe that can work with both setups (Figure 3B). The microsystem for autonomous control of the probe electronics can be seen in the same figure and consists of three parts: power, probe and control layers. The power layer (Figure 3D) is comprised of two coin batteries and a slide-switch positioned on a printed circuit board (PCB). Each battery has an energy capacity of 8mAh and weighs 120mg. Conductive adhesive was used to attach the batteries to the platform. The control layer (Figure 3A) is-
Figure 2: Cross-section (A) and illustrated diagram (B) of the flight muscles powering the up- and down-stroke of Manduca sexta wings.
Figure 3: The microsystem including microprocessor (A), flexible probe (B), silicon probe (C) and battery unit for power (D), the close-up view of the tip in (E) with the hole for muscle growth, the flexibility of the probe (F) and the assembled system (G). an 8×8mm2 PCB holding the microcontroller (Atmel Tiny13V) and an LED. The microcontroller was electrically connected to the PCB via flip-chip bonding. Wire-bonding was used to connect the PCB to the probe layer. The microfabricated silicon probe is sandwiched between these two layers (Figure 3G). The overall system has dimensions of 8×7mm2
and total mass of 500 milligrams.
The flexible probe can also be used in tethered setups by utilizing a FFC/FPC connector (Figure 10). All-silicon rigid probes, which provide higher stiffness for narrower cross-section enabling higher density probing, were also fabricated and tested (Figure 3C). Microprobe fabrication
Flexible PCB technology was used to deposit 18µm of Cu layer on 100µm thick Kapton-polyimide base material (Figure 5). Cu traces were coated with 20µm of LPI soldermask for insulation, except for the locations of the excitation/recording pads. 3µm of Electroless Nickel and Immersion Gold (ENIG) layer was deposited on the pads for biocompability. Each probe has a width of 400µm and each actuation pad is 75×75µm2 (Figure 4).
Figure 4: SEM image of the flexible-probe tip with expanded image of the ground and actuation pads
Figure 5: Cross-section (A) and description (B) of the layers used in the fabrication of the flexible probe
The relative stress between the implant and the tissue
was minimized by matched flexural rigidity (37.5N/m). For an all-silicon probe with a similar stiffness to the flexible probe, a silicon thickness of 30 µm would be required. Insertion results
The probe based microsystem platforms were inserted to the pupae 7 days before emergence (Figure 6). At this time, a thin thoracic skin is formed under the cuticle of the pupae. If inserted in earlier stages, the fluidity of the tissue prevented adequate sealing around the insert. When inserted later, some of the preformed muscle was damaged, leading to an inefficient bioelectronic interface. In addition, the flexible probes buckle and cannot be positioned to the targeted muscle groups when the thoracic skin is thicker.
Adaptation of probes by the muscle was highly maximized as the muscle grew around and through the hole of the probes (Figure 7iii), as observed under the microscope. Cuticle healing, therefore sealing, at the insertion points can be seen in the same figure (Figure 7i), both of which are indications of structural integration during metamorphosis.
When the probes were extracted, considerable tissue
was also removed in pupae-inserted probes, in contrast to adult inserted probes. Moths with inserted probes emerged with a success rate of 90% and have been electrically actuated.
Testing the tissue-probe coupling
The electrical coupling between the probe and the tissue was inspected before actuating the wing muscles using two
Figure 6: Pupal stage insertion (i) and successful emergence (ii). The microsystem platform on (ii) is held with tweezers to show wing opening of the moth. The X-Ray image of the dotted part (A) shows the probes inserted into the dorsoventral and dorsolongitudinal flight muscles. CT images (B) show components of high absorbance indicating tissue growth around the probe.
Figure 7: The crossection of thorax near the probe with explanatory schematic (ii) of thoracic flight muscles. Cuticle sealing (i) and muscle growth (iii) around the probe indicates integration by the body. (dl: dorsolongitudinal flight muscle, dv: dorsoventral flight muscle, see Figure 2) methods: (a) recording the muscle potentials during wing flapping, and (b) measuring I-V curves across the different probes in a tethered flight set-up (Figure 10). Probes that failed in any of these tests were discarded before the wing actuation experiments. The muscle potential recorded from the inserted probe was regarded as an indication of the goodness of the probe operation (Figure 8). The observed inter-spike duration is consistent with the wing flapping rate of moth (20-25Hz).
Rarely, the metal pads of the probe failed due to a currently unknown failure mechanism. Typical I-V curves of good coupling and such a failed probe can be seen in Figure 9. The actuated muscle fibers between the probe pads can be modeled with a simple 3 element RC network (Figure 9). Here RF denotes the resistance of intra- and extracellular fluids whereas RL is the leakage resistance of the membrane and CM is the membrane capacitance. The measured I-V curves (at DC) give the approximate addition of RL and RF. The resistivity values obtained from this sum (see Figure 9) for the good probes are in good agreement -
Figure 8: Muscle potential recorded from the dl muscles (see Figure 2 for dl) during wing-flapping. Observed spikes disappeared immediately with the recess of wing flapping.
Figure 9: The I-V curves of each electrical pad (measured with Keithley-4200) and the RC network modeling the muscle between the pads. The fitted lines and calculated resistivities are given in the table. Channel 4 (shown separately in 4th quadrant) has poor bio-electrical coupling. with the range reported for skeletal muscle in the literature (300-500 Ω⋅cm) [8-10]. The failed probes, however, reads abnormally reduced resisitivity values. Actuation of Flight Muscles
Phased actuation of probes with biphasic pulses allowed us to control wing motion highly selectively. Upstroke and downstroke actuation on “one” or both wings were demonstrated with power consumption of as low as 10 microWatts. By tethering the moth, we were able to affect the direction of insect flight by controlling the motion of the wing. Figure 10 shows unilateral up- and down-stroke evoked actuation of the wings. The wing actuation and direction of flight can be best seen in movie format [11].
Figure 10: The evoked up- and downstroke of a “single” wing obtained by applying 5V pulses to the indirect flight muscles (snapshots from the recorded movie). Under natural conditions, moths flap both wings together.
3. CONCLUSION We demonstrated a reliable hybrid tissue-electronics
interface in insects that provides flexibility against tissue movement. Inserting the probes at an early pupal stage ensures that the tissue grows around the probes for a highly natural implant. We also showed down- and up-stroke actuation of each wing separately, through which we were able to affect the flight direction of Manduca sexta. This work paves the way for future engineering approaches to utilize the bioelectronic interfaces especially for realizing insect cyborgs. 4. ACKNOWLEDGMENT
The authors would like to thank the members of the SonicMEMS Laboratory, especially Ayesa Paul and Abhishek Ramkumar for useful discussions and help during the experiments, the Beckman Institute of UIUC for being able to use their CT imaging facility and Janice Beal of Boyce Thompson Institute for rearing and supplying the moths. This work was fully supported by DARPA HI-MEMS program. The facilities used for this research include the SonicMEMS Laboratory, The NanoScale Science & Technology Facility (CNF) and The Nanobiotechnology Center (NBTC) at Cornell University. 5. REFERENCES
[1] G. Taubes, “Biologists and Engineers Create a New Generation of Robots That Imitate Life”, Science Magazine, April 7 2000, pp. 80-83, 2000. [2] C.P. Ellington, “The novel aerodynamics of insect flight: applications to micro-air vehicles”, The Journal of Experimental Biology, 202, pp.3439-348, 1999. [3] P. Mohseni, K. Nagarajan, B. Ziaie, K. Najafi, and S. B. Crary, “An ultralight biotelemetry backpack for recording EMG signals in moths,” IEEE Trans. Biomed. Eng., vol. 48, no. 6, pp. 734-737, June 2001. [4] J.R. Riley, “The flight paths of honeybees recruited by the waggle dance”, Nature, 435 (12 May 2005), pp. 205-207, 2005. [5] J. Mavoori, B. Millard, J. Longnion, T. Daniel, C. Diorio "A Miniature Implantable Computer for Functional Electrical Stimulation and Recording of Neuromuscular Activity", IEEE BioCAS 2004, Singapore, October 2004. [6] A. Paul, A. Bozkurt, J. Ewer, B. Blossey, and A. Lal, "Surgically Implanted Micro-Platforms in Manduca-Sexta", Solid State Sensor and Actuator Workshop, Hilton Head Island, pp. 209-211, 2006. [7] A. Bozkurt, A. Paul, S. Pulla, A. Ramkumar, B. Blossey, J. Ewer, R. Gilmour, A. Lal, "Microprobe Microsystem Platform Inserted During Early Metamorphosis to Actuate Insect Flight Muscle," IEEE Conference on Micro Electro Mechanical Systems (MEMS 2007), Kobe, JAPAN, pp. 405-408, 2007. [8] E. Zheng, S. Shao, J.G.Webster, “Impedance of skeletal muscle 1 Hz to 1 MHz”, IEEE Trans. Bio. Eng., vol. 31, pp.477-481,1984. [9] N. Sperelakis, T. Hoshiko, “Electrical Impedance of Cardiac Muscle”, Circ. Res., 9, pp.1280-1283, 1961. [10] N. Sperelakis, C. Sfyris, “Impedance analysis applicable to cardiac muscle and smooth muscle bundles,” IEEE Trans. Biomed. Eng., vol. 38, pp.1010-1022, 1991. [11]http://sonicmems.ece.cornell.edu/publications/movies/MEMS08.wmv