Raytheon Seekers

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Raytheon Seekers
Infrared Seeker Calibration Mechanism
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Raytheon Seekers

• Aaron ScrignarTeam Leader
• Eric Draves..Historian
• Trevor Moody.Web Page Des., Mediator
• Stacy Davison..Document Coord.,
  Financial Officer
• LaTanya WilliamsCommunicator

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Presentation Outline

• 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 sensors optical path to perform
  Non-Uniformity 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
Raw IR Image before NUC
Blurred IR Image with Lens in Position
Raytheon Seekers
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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
Raytheon Seekers
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Seeker Head Layout
Raytheon Seekers
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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
• Flight Conditions
• Lateral 0-3G
• Vibration 5G

Set Forward
Set Back
Lateral Balloting
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Scope of Design Constraints

• One quarter subjected to 10,000 Gs 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 its 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

• Frame
• Solenoid
• Positioning Arm
• Pin
• Bushing
• Return Spring

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Final Design
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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 RD Specialty Manco
• Phoenix, Arizona

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Selected Solenoid

• 3 VDC pulling solenoid
• 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

• Pin
• AISI 4130 Steel
• Sult 106 ksi

• Bushing
• Oilite Bronze - Oil Impregnated
• Self Lubricating Bushing

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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
• 7075-T6 Al Arm
• Germanium Lens
• Oilite Brass Bushing
• Tungsten Counterweight
• Material properties specified for each component

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FEA Mesh
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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

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Prototype Cost
Machine Work Parts Frame (2) Arm (2) Pin Bushing (2) Solenoids (14) Solenoid Screws (144) Miscellaneous (Spring, Wire, etc.) 450.00 - 115.00 89.92 24.00 5.00
TOTAL 683.92
Cost Per Unit 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 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
• 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?