Simulation of an accelerometer-based feedforward vibration suppression in an adaptive optics system for MICADO

In large telescopes like the E-ELT, the performance of the Adaptive Optics (AO) system is not only dominated by atmospheric disturbances but also by high frequency structural vibrations. Currently these vibrations are suppressed by a model-based feedback controller. When observing faint stars, the performance is reduced by a lower bandwidth because of a larger exposure time of the wavefront senor. The "control bandwidth" can be increased by an additional accelerometer-based feedforward controller, which is independent of the exposure time. This vibration suppression concept was studied in an AO end-to-end simulation and first investigations at a laboratory setup have been performed. Based on these results, we discuss the application for an on-sky testing at the LBT and an implementation in the MICADO AO.

[1]  G. Agapito,et al.  Optimal control techniques for the adaptive optics system of the LBT , 2008, Astronomical Telescopes + Instrumentation.

[2]  Oliver Sawodny,et al.  Accelerometer-Based Online Reconstruction of Vibrations in Extremely Large Telescopes , 2014 .

[3]  T. Fusco,et al.  SPHERE eXtreme AO control scheme: final performance assessment and on sky validation of the first auto-tuned LQG based operational system , 2014, Astronomical Telescopes and Instrumentation.

[4]  Thierry Fusco,et al.  First laboratory validation of vibration filtering with LQG control law for adaptive optics. , 2008, Optics express.

[5]  David G. Sandler,et al.  Adaptive optics for diffraction-limited infrared imaging with 8-m telescopes , 1994 .

[6]  D. M. Alloin,et al.  Adaptive optics for astronomy , 1994 .

[7]  Eric Gendron,et al.  First on-sky SCAO validation of full LQG control with vibration mitigation on the CANARY pathfinder. , 2014, Optics express.

[8]  T. Bertram,et al.  Vibration measurements at the Large Binocular Telescope (LBT) , 2008, Astronomical Telescopes + Instrumentation.

[9]  Caroline Kulcsar,et al.  Tip-tilt disturbance model identification for Kalman-based control scheme: application to XAO and ELT systems. , 2010, Journal of the Optical Society of America. A, Optics, image science, and vision.

[10]  J. Conan,et al.  Wave-front temporal spectra in high-resolution imaging through turbulence , 1995 .

[11]  Oliver Sawodny,et al.  Real-time vibration compensation for large telescopes , 2014 .

[12]  Oliver Sawodny,et al.  OVMS-plus at the LBT: disturbance compensation simplified , 2016, Astronomical Telescopes + Instrumentation.

[13]  Rolf Isermann,et al.  Identification of Dynamic Systems , 2011 .