Transcript PDR_Virginia-VirginiaTech - Colorado Space Grant Consortium

Hy-V .1
Skin Friction Sensor Experiment
Presenters:
Ryan F. Johnson
Mitchell Foral-Systems
University of Virginia
November 24, 2008
Outline
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Overview
Science of Sensor
Special Mission Requirements
Mechanical Drawings
Commands and Sensors
Test Plans
Compliance and Shared Logistics
Management Update
Schedule
Missing:
– Subsystem Requirements
– Parts list
Overview
• Objective:
– To test a newly designed skin friction
sensor fabricated by ATK
– Students to gain experience in several
areas of engineering by engaging in a
student run sounding rocket experiment
• Expected findings:
– Functionality of the skin friction sensor
– Analytically determined skin friction
matches that of the sensor
– Reusability of sensor
– Survivability of sensor
Science of Sensor
• Skin friction is a necessary
element for the understanding of
fluid dynamics
• Skin friction
– The reason we fly
– The reason why we can’t fly that
fast
• The more we understand skin
friction the better chance we
have to design flight vehicles
that can sustain high speed flight
Image from NASA HYPER-X found: http://rocketpedia.rocketmavericks.com/aerodynamics/images/5/55/X-43A_(Hyper_-_X)_Mach_7_computational_fluid_dynamic_(CFD).jpg
Science of Sensor
• Sensor uses an interferometer to
measure deflections that will
translate into voltage outputs
• Interferometer
– Uses two light waves that intersect at
a certain point
– Skin friction causes a defection of one
of the reflective mirrors
– Depending on their deflections,
constructive and destructive
interference can be measured
– This measured interference will then
be translated into an output voltage
t
Special Mission Requirements
• For experiment, UVA needs atmospheric access
other than the supplied static ports
• These ports will need to accommodate the skin Top
View
friction sensors
– Adapters will be designed by UVA and cleared by
NASA
– Will communicate with NASA over the next few
weeks leading to CDR to determine the best route
to accommodate sensor
• PRIORITY: Sensor integration will need to be
water tight
– Water leak will damage other instruments and void
compliance agreement
• Any assistance from boulder in this would be
greatly appreciated
Rocket
Interior
Rocket
Skin
Flow
Mechanical Drawings:
RockSAT Can Base
Sensor bases: One for
Each Sensor
PCM104+
Lifted Base Plate
Mechanical Drawings
RockSAT Can with Integration of sensors
Two
sensors
attached to
wall
Mechanical Drawings
RockSAT can integrated into rocket Skin
•Two sensors
•Two holes
•2-¾” taps
•Need to be sealed
Mechanical Drawings
Possibilities for sensor integration
1. Tap holes
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Can seal holes with rubber sealing to
prevent leaks
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Would need to drill more holes to bolt
sensors to wall
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2. Use a skin mount
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Mounts into a window located
on the outer wall of the rocket
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Less holes in skin
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Integration into rocket easier
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Future Analysis
•Center of mass
•Use Cosmos to create G-Loads on payload
•Tests material selection and design
•Look into water tight sealing
•Using rubber gasket (seen to the right)
•Using spray foam
•Calculate true center of mass
•Currently center of mass can be counterweighted
because payload weight is 3lbs max
•True center of mass will be known after material
selection and counterweights are chosen
•Determination of Skin friction from CFD
•Determination of wall temperature from CFD
Flow Chart Diagram for Flight Test
Assessment
of Test
Board Turns
on
Sensors
Power on
Ignition
of Rocket
Recovery of
DATA
Tripping of
G-Switch
Code Execution
Begins
Is memory
Full?
No
Keep Executing
Code
Recovery of
Rocket
Yes
Stop Code
Splash
Down
De-integrate
Sensors
Commands and Sensors
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Data Flow:
Shear sensor -> Circuit board -> CPU -> Software
-> Storage
Sensor:
– Operates in excess of 1000 degrees C.
– Between 4 and 10 mm^2 in surface area.
– Frequency response in the kHz range.
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Sampling: variable; factory default of 50Hz.
Storage: 16MB.
Sample time: ~2.7 minutes at 50Hz for 16-bit
data.
Software:
Poll for incoming data -> optimize for storage ->
store
Maybe sample at very high Hz, store mean at low
Hz.
Test Plans
• Preflight Testing:
• Sensor outputs between 0 and 5 V
data.
• Our microprocessor/board has a
software suite to test programs
written for it. Feed it fake sensor
data.
• Once those tests pass, we can
attach the sensor to the board and
run actual tests.
• Flight:
• Potential failure points:
– Hardware failure.
– Flight lasts longer than expected,
run out of storage for samples.
Compliance and Shared Can Logistics
– Compliance:
• Mass, Volume
– Currently 3lb payload (not
including can)
• Payload activation
– Remove before flight pin
– G switch
• No volt requirement????
– Can Logistics:
• Shared with VT
• VT supplies PC104+
• VT has one other experiment
(TBD)
• Both collaborate on rocket
integration and design
UVA Hy-V 0.1 Team
– Management
• Ryan Johnson-Program Manager
• Elizabeth Martin- Technical Advisor
– Mechanical Engineering
• Archie Raval
• Shaun Masavage
• Jesse Quinlan
– Aerospace Engineering
• Naeem Ahmed
– Systems:
• Mitchell Foral
• Chris Sweeney
Schedule
– Next few weeks
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Coordinate with NASA and Boulder on special requirements
Order special components
Material Selection
Center of Mass Calculation
Complete Systems Charts (Coding, Block Diagrams)
Secure Funding
– VSGC
– ATK
– Next Few Months
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Calculate expected shear
Receive sensors
Finish coding for PC104
Complete and finalize models
– Run G Load analysis
• Determine max, min shear for sensor
• Determine Total temperature for sensor
• Run preliminary tests
Conclusion
– We have A LOT to do!!!!
• We are not lazy, just have had bad luck
• Need to catch up, probably more than any other
RockON Team
• Complete confidence that Hy-V Team can do this
• With the help of Advisors from UVA, VT, UC at
Boulder, and NASA Wallops we can make this
happen