A Desktop Fast Hybrid Test Platform

1. A DesktopFast Hybrid TestPlatform Gary Haussmann, Ph.D. George E. Brown, Jr. Network for Earthquake Engineering Simulation http://nees.colorado.edu Phone: (303) 735-0302 Fax: (303) 492-7317 Gary.Haussmann@colorado.edu

2. Outline • Background • Motivation and Goals • Hardware Configuration • Software Configuration • Summary and Conclusions

3. Background • Terminology: • Hybrid test: combined simulation and physical interaction • Fast Hybrid: simulation runs at/near real-time • CU-Boulder NEES site has a production FHT system for large scale tests

4. Motivation • A Need for Quick FHT Sessions • Demonstrations • Educational Projects • Research Prototypes • Full-scale production system is large and expensive • Long setup/breakdown times • Complex interaction of multiple hardware boxes • Prohibitive for quick experiments

5. FHT Desktop Goals • Rapid deployment • Inexpensive • Accessible

6. Shaking Table Hardware Configuration • Physical Specimen • Accessed via LabView • Simulation Computer • Real-time LabView OS • Simulation and network • Control Computer • Graphics and user interface Physical Specimen NI DAQ Simulation Computer with Real-time OS Ethernet Display and Control MS-Windows Computer

7. Shaking Table 1 Hardware Configuration • Physical Specimen is controlled directly by DAQs • Actuator accepts command displacement • Load cell produces measured force • LVDT produces measured displacement Command Displacement Actuator Force Load Cell LVDT Displacement

8. Shaking Table 2 Hardware Configuration • Simulation/Physical Interface • Consistent with production system • Simulation sends displacement to actuator • Simulation receives force and displacement • Data sent to separate control computer Command Displacement Actuator Force Ethernet Load Cell Simulation LVDT Displacement

9. Shaking Table 3 Hardware Configuration • Control computer • Graphical display of simulation state • Information about instruments/physical state • GUI to control graphics and simulation Command Displacement Actuator Force Ethernet Load Cell Simulation Control/GUI LVDT Displacement

10. Shaking Table Software Configuration • Three Key Processes: • Simulation • Network • Control Computer with Real-time OS MS-Windows Computer User Interface/ Display Process Ethernet Network Process Simulation Process Real-time Portion Physical Specimen

11. Software Configuration • Simulation Process • Runs on simulation computer • Runs as a Real-time Process • C/C++ code DLL embedded into LabView • FE Framework Details • Implicit dynamics (Alpha method) • Nonlinear formulation; iterative solution • Hybrid simulation embedded in the iterative process

12. Software Configuration • Hybrid Equations • Command displacement • Measured displacement • Measured force

13. Software Configuration • Network Process • Runs on simulation computer • Runs as a non-real-time Process • Sends data to control computer • Sends Ethernet/IP/UDP datagrams at 30Hz rate • Network Module Details • C++ code to pack/unpack simulation state for networking

14. Software Configuration • Display Process • Runs on control computer • Graphical display of most-recent known state • Asynchronous updates received from Network Process invoke display update • Display Platform Details • Object-oriented Graphics Rendering Engine (OGRE) • Full 3D, 60Hz display

15. Summary & Conclusion • Low-cost Hybrid Test Platform Completed • Fast hybrid simulation • Multiple-DOF • Enables fast modification/prototyping • Planned use for incoming short course • Future work • Parallel computation • Continuum elements

16. Demonstration