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Modeling, experimental validation, and model order reduction of mirror thermal dynamics.
Optics Express
|October 7, 2021
Summary
Accurate thermal modeling is crucial for optical systems. This study presents a combined approach using first-principle physics, experiments, and model reduction to predict temperature changes and reduce optical aberrations, enabling better system design.
Area of Science:
- Optical Engineering
- Thermal Dynamics
- Control Systems
Background:
- Optical systems are sensitive to temperature variations and gradients, impacting performance through thermally induced wavefront aberrations.
- Accurate modeling, estimation, and control of thermal dynamics are essential but challenging due to model uncertainties, nonlinearities, and high dimensionality.
Purpose of the Study:
- To develop and validate a synergistic modeling framework for predicting thermal dynamics in optical systems.
- To investigate the influence of mirror materials on reduced-order model derivation.
- To provide a methodology for controlling thermal dynamics and mitigating aberrations.
Main Methods:
- Combined first-principle heat transfer modeling with experimental validation.
- Utilized finite element techniques and model order reduction.
- Experimentally validated on an 8-inch mirror prototype and applied to a parabolic mirror with a honeycomb structure.
Main Results:
- Accurate prediction of temperature transients over several hours was achieved.
- Demonstrated that mirror thermal dynamics can be approximated by low-order state-space models.
- Investigated the impact of materials like aluminum, beryllium, Zerodur, and ULE on model reduction.
Conclusions:
- The synergistic modeling framework effectively predicts thermal dynamics in optical systems.
- Reduced-order models are feasible for approximating complex thermal behaviors.
- The approach aids in the design and control of optical systems to minimize thermal aberrations.
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