Raytheon Seekers
Infrared Seeker
Calibration Mechanism
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Raytheon Seekers
Aaron Scrignar……Team Leader
Eric Draves………..Historian
Trevor Moody…….Web Page Des.,
Mediator
Stacy Davison……..Document Coord.,
Financial Officer
LaTanya Williams…Communicator
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Presentation Outline
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Client Description
Problem Definition
What is Infrared Imaging?
Project Requirements
Design Method
Prototype Design
Analysis Process
Project Spending
Time Log
Conclusion
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More about… Raytheon
• One of the largest defense electronics contractors in the
world. Leader in defense electronics, including:
– Missiles; Radar, Sensors and Electro-Optics
– Intelligence, Surveillance and Reconnaissance (ISR)
– Missile Defense
• Chairman & CEO: Daniel P. Burnham
• 2002 Revenue
– $16.8 Billion
– 62% of sales to U.S. Department of Defense
• 79,000 employees worldwide
• Headquarters located in Lexington, MA
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Client Contact
• Brian Scott
– B.S.E. in Mechanical Engineering at NAU
– M.S. in Mechanical Engineering at UofA
– Employee of Raytheon since graduation
• Missile Systems – Future Combat Systems
• Tucson, Arizona
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Problem Statement
A preliminary design and a proof-of-principal
prototype are needed for a window positioning system
to be used in a tank-launched projectile. The device
must position a small germanium window into an
infrared sensor’s optical path to perform NonUniformity Compensation.
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Project Requirements
NUC Mechanism must:
• Survive 10KG launch acceleration normal to the
window face
• Packaged in 0.235” thick by 2.89” diameter cylinder,
excluding electronics
• Move a 0.50” x 0.44” x 0.04” thick Germanium lens to
cover a photocell array
• Require less than 24 Watts at a maximum of 24 Vdc for
less than 1 second
• Move lens in and out of the field of the array in less than
1 second, and remain in position for 1 second
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What Is Infrared Imaging
• Light at frequencies
below visible red are
considered infrared
• All objects emit
infrared energy at
ordinary temperatures
• Objects with higher
temperatures emit
more infrared energy
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Infrared Seeker Operation
• Modern “Heat Seekers”:
– Employ advanced
infrared sensor arrays
– Utilize computer
programs to select,
target, and guide
munitions towards
specific images
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Non-Uniformity Compensation (NUC)
NUC is necessary to adjust for different pixel sensitivities
which could cause erroneous targeting by seeker computer
Germanium Lens
Moved in Front
of IR Array
Blurred IR Image with
Lens in Position
Raw IR Image before
NUC
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Non-Uniformity Compensation (NUC)
Computer algorithm
adjusts gain factors of
individual pixels so that
a uniform image results
from a uniform scene
NUC
Germanium Lens Moved
Out of Position
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Seeker Head Layout
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Rail Gun Test
• 155mm Howitzer
fires projectile
into water filled
trough to provide
firing conditions
and “soft catch
capability
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Acceleration Time Histories
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Acceleration Definition
• Launch Conditions
– Set Back 10,000G
– Set Forward 2,000G
– Lateral Balloting 3,300G
Set Forward
• Flight Conditions
– Lateral: 0-3G
– Vibration: 5G
Set Back
Lateral Balloting
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Scope of Design Constraints
• One quarter subjected to 10,000 G’s weighs
approximately 120 lbs.
• The restricted thickness of the available
volume is less than ¼ of an inch
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Design Philosophy
• K.I.S.S.
- Minimize complexity of the design to reduce
probability of failure
• Keep close contact with client
– Bring attention to potential design problems
before it’s too late
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Design Process
• Brainstorming - Mechanism ideas
• Mechanism Selection - Based on size constraints
• Modeling - Cardboard & CAD models to assess
geometries
• Analysis - Hand calculations, Adams, COSMOS/M
• Fabricate Prototype – CNC
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Final Design
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Frame
Solenoid
Positioning Arm
Pin
Bushing
Return Spring
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Final Design
Frame Design
• Frame supports components and other
seeker optics
– Modified to eliminate unnecessary weight
– Recessed regions for return spring and
counterweight clearance
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Frame Design
• Frame
– 6061-T6 Aluminum
– Sult = 45 ksi
– CNC work done by R&D
Specialty Manco
– Phoenix, Arizona
Selected Solenoid
• 3 VDC pulling solenoid
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Electro Mechanisms, Inc
Commercially available PO-25
Fits within required dimensions
Provides minimum of 2 oz. of
force at 3X nominal voltage
(18 Watts)
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Positioning Arm
• Positioning Arm
– 7075-T6 Aluminum
– Sult = 82.7 ksi
• Bushing
– Oilite Bronze - Oil
Impregnated
– Self Lubricating Bushing
• Pin
– AISI 4130 Steel
– Sult = 106 ksi
Pin Connection Design
Press Fit Withstands 120lb Vertical Force
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Analysis Justification
• Deformation of surfaces are within
tolerances defined by the optical engineer
• Deformation of support structure for optics is
within tolerance and creates no interference
– No yielding through cross section of part
• No ultimate failures occur
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Analysis Focus
• Static Analysis
– Pin joint withstands launch accelerations
– Arm deflection does not produce ultimate failure
• Dynamic Analysis
– Solenoid and spring actuation times
– Verification of solenoid adequacy
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Finite Element Analysis
• COSMOS/M
– 3-D 20 Noded Quadrilateral Elements
– Body (Acceleration) Load
• Modeled Positioning Arm & Components
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7075-T6 Al Arm
Germanium Lens
Oilite Brass Bushing
Tungsten Counterweight
• Material properties specified for each component
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FEA Mesh
Von Mises Stress Plot
smax = 80.3 ksi
F.S. = 1.03
Does Not Yield
Through
Cross-Section
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Dynamic Analysis
• Adams software used for
dynamic analysis w.r.t. arm
rotation
• Employed actual solenoid force
function curve and spring force
• Analysis Performed:
– Actuation & return times
– Forces due to snubbing of
arm rotation
– Verification of solenoid
strength sufficiency over
entire actuation distance
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Adams Simulation
Actuation time = 0.027 sec
Spring Return = 0.028 sec
Prototype Cost
Machine Work & Parts
Frame (2)
Arm (2)
Pin & Bushing (2)
Solenoids (14)
Solenoid Screws (144)
Miscellaneous (Spring, Wire, etc.)
$
$
$
$
$
$
TOTAL
Cost Per Unit
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450.00
115.00
89.92
24.00
5.00
$ 683.92
$ 341.96
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Total Project Spending
Modeling Supplies
$ 42.00
Prototype Cost
$ 683.92
Documentation
$ 400.00
Presentation Supplies
$ 50.00
Travel & Miscellaneous
$ 730.00
TOTAL
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$1,905.92
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Project Budget
• Provided Funds by Raytheon
– $ 3,000
• Total Project Spending
– $ 1,906
• Donation to the College of Engineering & Technology
– $ 1,094
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Time Log
Total Project Hours for Spring Semester
684.5 hrs
Avg. Hours Per Team Member:
136.9 hrs
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Conclusion
• The balanced swing arm design is simple and
efficient in providing the required lens
motion while withstanding the
environmental constraints
• A prototype that meets project specifications
will be delivered to Raytheon on time and
within budget
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Acknowledgements
• Brian Scott
– Raytheon Missile Systems
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Dr. Ernesto Penado, Advisor
Dr. David E. Hartman, P.E.
Dr. John Tester
NAU Machine Shop
– Don McCallum, Daniel, & Rus
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Questions?