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Highlights of CDCSS-UMD Accomplishments

Highlights of CDCSS-UMD Accomplishments. Presentation to Dr. Randy Zachery Army Research Office May 25, 2004 at Harvard University. Accomplishments. Adaptive Optics

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Highlights of CDCSS-UMD Accomplishments

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  1. Highlights of CDCSS-UMD Accomplishments Presentation to Dr. Randy Zachery Army Research Office May 25, 2004 at Harvard University

  2. Accomplishments • Adaptive Optics • - Proof-of-concept experimental demonstration of the liquid crystal light valve (LCLV)-based high resolution wave-front control system (nonlinear Zernike filter realization) • - Simulation results show effectiveness against atmospheric turbulence • - Global nonlinear stability analysis for the continuous system model of the wave-front control system • - Patent disclosure (PS-2001-078) jointly to University of Maryland and Army Research Laboratory: Wave-front phase sensors based on optically or electrically controlled phase spatial light modulators for wave-front sensing and control (M.A. Vorontsov, E. W. Justh, L. Beresnev, P. S. Krishnaprasad, J. Ricklin)

  3. From nonlinear Zernike filters to high-resolution adaptive optics

  4. Accomplishments • Modeling, Computation and Control of Magnetostrictive Hysteresis • - Effective numerical computation of magnetostrictive hysteresis in materials such as Terfenol-D using the Landau-Lifshitz-Gilbert (LLG) equation to model ferromagneto-dynamics, and elastic rod theory to model actuator movement • - Hierarchical tree-structured Fast Multipole Algorithm to compute magnetostatic term in effective field, coupled to a new Cayley transform- based geometric integrator for solving the LLG equation, to compute theoretical hysteresis curves • - Modeling of rate-dependent phenomena in hysteretic actuators due to eddy current effects by a novel extension of the Preisach model • - Fast inversion algorithm for Preisach-type model to compute control signals for tracking specified output trajectories. • - New Hamilton-Jacobi theory for robust control of hysteretic systems

  5. Sectional view of the Etrema magnetostrictive actuator

  6. Higher Order Geometric Integrator— Performance Comparision Comparison of integration schemes on a 2 by 2 by 4 grid, using the result of RK4 with much smaller stepsize as the benchmark.RK4: Runge-Kutta 4-th order, MP: Mid-point rule. Cay_RK4: Cayley transform with RK4.

  7. Higher Order Geometric Integrator— Performance Comparision Comparison of performance on norm preserving

  8. Higher Order Geometric Integrator— Summary of Features • Fast • Explicit • On the right track • Accurate due to high order • Norm preserving

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