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The Search For Dark Energy - 4.26.2010 - Joe Beno
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The Search For Dark Energy - 4.26.2010 - Joe Beno

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  • CEM, with support from MDO staff, has identified the major interfaces for the Tracker System which are illustrated in this figure. While this does not illustrate all interfaces, it identifies CEM’s major responsibilities and where CEM must interface with other CEM components or MDO provided hardware or software. Items in grey are items which CEM has primary responsibility for. Items in blue are items which MDO is providing. An interface between a blue and gray item is considered an “external” interface while interfaces between items of the same color are “internal” interfaces. Due to their number of parties involved “external” interfaces are more critical. Items on a green background are items that will not be located on the telescope structure. The types of interfaces, structural, information, thermal or fiber optic are correspondingly color coded black, blue, red, and orange as well. At PDR the only significant discussion pertaining to this slide had to do with who will ultimately fabricate the Strongback for the Wide Field Corrector. Options ranged from the WFC manufacturer to MDO to CEM. Follow-up meetings indicate the Strongback will be designed and fabricated by CEM which will split the Strongback and WFC box and create a new external interface between those two components.
  • Images Left to right: 1) Streamers w/ pressure dist. 2) Surface pressure dist. 3) Flow velocity, implications for vibration study
  • Probably 4 backup slides that go with this on tasks, schedule, budget, risks
  • Transcript

    • 1. Search for Dark Energy Dr. Joe Beno University of Texas Center for Electromechanics [email_address] (512) 232-1619
    • 2. Overview Scientists can’t find 70% of the energy in the Universe. UT’s Hobby Eberly Telescope is going to look for it. CEM’s 20 ton precision robot will do the work.
    • 3. What is Dark Energy? More is unknown than is known. We know how much dark energy there is because we know how it affects the Universe's expansion. Other than that, it is a complete mystery. But it turns out that roughly 70% of the Universe is dark energy. Dark matter makes up about 25%. The rest - everything on Earth, everything ever observed with all of our instruments, all normal matter - adds up to less than 5% of the Universe. The thing that is needed to decide between dark energy possibilities - a property of space, a new dynamic fluid, or a new theory of gravity - is more data, better data. Dark Energy, Dark Matter - NASA April 2010.mht News Release Number: STScI-2001-09 http://hubblesite.org/newscenter/archive/releases/2001/09/image/f/
    • 4. HET Dark Energy Experiment http://hetdex.org/hetdex/search_area.php http://hetdex.org/hetdex/index.php The map will allow HETDEX astronomers to measure how fast the universe was expanding at different times in its history. Changes in the expansion rate will reveal the role of dark energy at different epochs. Various explanations for dark energy predict different changes in the expansion rate, so by providing exact measurements of the expansion, the HETDEX map will eliminate some of the competing ideas. HETDEX will be the first major experiment to probe dark energy. During three years of observations, HETDEX will collect data on at least one million galaxies that are 9 billion to 11 billion light-years away, yielding the largest map of the universe ever produced.
    • 5. HET Scale Up IS Necessary To Reduce Viewing Time From Decades to Years During each observation, HET will see an area of the sky that is more than 30 times greater than it sees today. CEM is responsible for upgrading the Tracker – an 18 ton robot that positions the HET Prime Focal Instrument Package.
    • 6. Tracker Subsystems Tracker Function: Position optical package (payload) where commanded and align it perpindicular to primary mirror Payload: 3.5 tons Tracker: 55’ above floor; 35’ long; 18’ high; 18 tons Bridge Carriage Hexapod PFIP Support Structure Rho Stage Lower X-Drive Y-Drive Upper X-Drive Payload
    • 7. HET Tracker is a large robot. . . ~ Size: 55’ above floor; 35’ long; 20’ high.
    • 8. Major Interfaces on Tracker Upper Hexagon of Telescope X-Axis Drive Cable and Tube Handling Fiber Management System Thermal Control System Tracker Computer Y-Axis Drive Tracker Bridge Telescope Control System Carriage Tracker Hexapod PFIP Structure WFC and Strongback Rho Stage Optical Bench Data Logger Payload Alignment System Provided by MDO Provided by CEM Off Telescope VIRUS Structural Information Thermal Fiber Optics
    • 9. Performance Requirements
    • 10. Integrated Design and Analysis FMEA UMBRELLA
    • 11. Tracker Motion in Solid Works
    • 12. Coupled Mechanical-Software Model of Tracker and Controller
      • Tracker Controller Block: Actual control code that migrates via auto-code generation to tracker controller hardware – simplified modification process with proven industry standard Matlab-Simulink GUI driven code development process.
      • Control Algorithms: Proven in realistic simulation environment before transferring to hardware.
      • Controller Documentation: MS Word documents embedded in Simulink blocks for easy reference.
      • Tracker Dynamic Model: Sym-Mechanics dynamic modeling environment linked with Matlab Virtual Reality toolbox for visualization.
      • Component Specifications: Performance “proven” in realistic coupled simulation environment.
    • 13. Integrated Model of Tracker and Controller
    • 14. Tracker Bridge
    • 15. Bridge Key Results
    • 16. Lower Hexapod Frame Structural Analysis
    • 17. LHF Analysis Results
    • 18. Hexapod Configuration Study Static Analysis Selected Results Study # 40 selected as baseline design. Best compromise of low frame displacement and low strut force requirements.
    • 19.
      • HETDEX Hexapod Motion
        • Six independent actuators
        • Infinite actuator length possibilities
        • ‘ Manually’ moving model to investigate collisions severely limits positions that can be investigated
      • Collision Detection Tool
        • Uses SolidWorks programming interface to automate positioning of hexapod and check for collisions
        • Allows very large number of position evaluations
      • ‘ Optimization’ Study
        • MS Excel solver seeks near collisions, given initial starting position
        • Random hexapod positions used as starting points
      Collision Study ~A dozen new problematic actuator position combinations identified.
    • 20. Available Volume Study
      • Needed understanding of available space for additional hardware
      • Hexapod motion and number of potential positions too complex to manually determine available volume
      • SolidWorks programming interface used for the study
        • Initial volume was defined for evaluation
        • Hexapod exercised thru it’s range of extreme positions
        • Remaining volume was determined that did not collide with existing hardware
    • 21. IFU Accelerated Life Cycle Test
    • 22. Wind Loads
      • 3-D CFD analysis and flow visualization estimate effects of wind gusts on Fiber Management System.
        • Worst case 55mph (26m/s) broadside gust
        • Wind loads are manageable (~ 350 lbf. over entire span)
        • Analysis will be refined with actual measured wind data
        • Wind induced loads influence tracker design, especially bridge
      Flow streamlines from right to left Surface pressure distribution Velocity distribution
    • 23. Pre-Assembly, De-Bugging, and Process Development at CEM
      • Full scale Tracker and FMS installation with mock (surrogate) Telescope hexagon, mock elements of VIRUS and mock payloads in CEM’s high bay in 2010
      • Tracker, FMS, and control system debugged, tested and validated against test matrix at CEM
      • Prior to installation at Telescope
        • Assembly and installation procedures and tooling refined at CEM
        • Telescope personnel training at CEM
        • Tracker-Telescope Control System software integration trials at CEM
        • Documentation completed/updated with “as-built” data and procedures
      • CEM team provide on-site support during installation and debugging at Telescope
    • 24. Schedule
    • 25. Upcoming SPIE Publications Plus 3 Master’s Thesis and 1 Master’s Report. Beno, Booth, Mock, An alternative architecture and control strategy for hexapod positioning systems to simplify structural design and improve accuracy Hayes, Good, Jason Mock, Rich Savage, John Booth, Beno Design of Performance Verification Testing for HETDEX Tracker in the Laboratory Joey Zierer, Jason Mock, Joseph H. Beno, Paolo Lazzarini, P.Fumi, E.Anaclerio (ADS International), John Good, John Booth The Development of high-precision hexapod actuators for the Hobby-Eberly Telescope Dark Energy Experiment (HETDEX) Nicholas T. Mollison, Richard J. Hayes, John R. Jackson, Richard D. Savage, Marc D. Rafal, Joseph H. Beno Collaborative engineering and design management for the Hobby-Eberly Telescope tracker upgrade M. Soukup, Nicholas T. Mollison, Jason R. Mock, Joseph H. Beno, Gary J. Hill, John M. Good, Brian L. Vattiat, Jeremy D. Murphy, Seth C. Anderson, Eric P. Fahrenthold Design of the fiber optic support system and fiber bundle accelerated life test for VIRUS Michael S. Worthington, Timothy A. Beets, John M. Good, Brian T. Murphy, Brian J. South, Joseph H. Beno Design and development of a high-precision, high-payload telescope dual-drive system Michael S. Worthington, Steven P. Nichols, John M. Good, Joseph J. Zierer, Jr., Nicholas T. Mollison, Ian M. Soukup Design and analysis of the Hobby-Eberly Telescope dark energy experiment (HETDEX) bridge Jason Mock, Joe Beno, Joey Zierer, Tom H. Rafferty, Mark E. Cornell Tracker controls development and control architecture for the Hobby-Eberly Telescope dark energy experiment Gregory A. Wedeking, Joseph J. Zierer, Jr., John R. Jackson Kinematic optimization of upgrade to the Hobby-Eberly Telescope through novel use of commercially available three-dimensional CAD package Nicholas T. Mollison, Jason R. Mock, Ian M. Soukup, Timothy A. Beets, John M. Good, Joseph H. Beno, Herman J. Kriel, Sarah E. Hinze, Douglas R. Wardell Design and development of a long-travel positioning actuator and tandem constant force actuator safety system for the Hobby-Eberly Telescope wide-field South, Good, Booth, Worthington, Zierer, Soukup Wind Loading analysis and strategy for deflection reduction on HET dark energy experiment upgrade James T. Heisler, John M. Good, Richard D. Savage, Brian L. Vattiat, Richard J. Hayes, Nicholas T. Mollison, Ian M. Soukup, Integration of VIRUS spectrographs for the HET dark energy experiment
    • 26. One Last Thought . . . The Dark Energy question is one of the most important open questions for the international physics and astronomy community. The University of Texas is playing a leading role on this question. CEM is devoting ~ 1/3 of its engineering staff to accomplish a critical task that enables U.T.’s Dark Energy Survey. CEM does not earn overhead on the HETDEX program . . . so bid and Proposal Funding from U.T. is reduced.
    • 27. Questions & Discussion