Browsing by Author "Störkle, Johannes"

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Open Access
Dynamic simulation and control of optical systems
(2018) Störkle, Johannes; Eberhard, Peter (Prof. Dr.-Ing. Prof. E.h.)
This thesis deals with the simulation-based investigation and control of optical systems that are mechanically influenced. Here, the focus is on the dynamic-optical modeling of vibration-sensitive mirror systems, which are utilized, e.g., in large astronomy telescopes or high-precision lithography optics. The large-area primary mirrors of telescopes typically consist of many individual hexagonal mirror segments, which are positioned with precise sensors and actuators. Furthermore, an adaptive optical unit usually compensates for the optical aberrations due to atmospheric disturbances. In practice, these aberrations are detected, and corrected, within a few seconds using deformable mirrors. However, to further improve the performance of these optical systems, dynamical disturbances in the mechanics, i.e., small movements and deformations of the optical surfaces, must also be taken into account. Therefore, multidisciplinary simulation methods are developed and presented. Based on this, the dynamical-optical system behavior is modeled using model-order-reduced, flexible multibody systems. Hence, the dynamical analysis of the mechanical-optical system can be performed at low computation costs. Thanks to the optical analysis in the time domain and using Fourier-optical concepts, one can also simulate exposure processes. To actively compensate for aberrations due to mechanical vibrations, model-based control strategies are also designed. They are not only demonstrated by means of simulation examples, but also illustrated through a laboratory experiment. The latter is realized with a low-cost test setup for student training using Arduino microcontrollers, position and force sensors, as well as high-speed cameras.
Open Access
Model-based vibration control for optical lenses
(2020) Störkle, Johannes; Eberhard, Peter
This work presents a contribution to the active image stabilization of optical systems, involving model development, control design, and the hardware setup. A laboratory experiment is built, which demonstrates the vibration sensitivity of a mechanical-optical system. In order to stabilize the undesired image motion actively, a model-based compensation of the image vibration is developed, realized and tested. Beside a linear actuator motion system, a force sensor system and a position sensor system are introduced and analyzed. In particular, various low-cost hardware components of the Arduino platform are used, which support the deployment of the controller software based on Matlab-Simulink. The remaining image motion is measured with a high-speed vision sensor system and the performance of the overall system is assessed.