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## Fast and high-performance control for E-ELT optical instruments

 Project members: prof. M. Verhaegen, P.R. Fraanje
 Keywords: Distributed control, System identification and estimation, Imaging and adaptive optics

## Project description

The large diameter of extremely large telescopes (ELTs) will enable high angular resolution (<10mas in the near-infrared, 1mas = 1 milli arcsecond equals about 5 nano-radians) and high contrast astronomical observation necessary for detection of small (earthlike) exoplanets and deep space observation to study the history of the universe. For example with the 42m diameter European-ELT (E-ELT) the diffraction limit of 1$\mu$m wavelengths is only 6mas. However, this diffraction limit will not be achievable without large scale adaptive optics (AO) to compensate for distortions due to (multilayer) atmospheric turbulence, wind forces, (ground) vibrations, temperature variations, and optical alignment errors.

To obtain diffraction limited performance the AO system need to have 40.000 actuators and sensors and a sampling rate in the order of several kHz. The computational complexity of standard PI controllers consisting of matrix vector products is in the order of several Tflops, which is infeasible with relatively low cost computing hardware.

In this project we will develop efficient control algorithms that can be implemented on low cost multi-core hardware.

## Project goals:

• Develop and implement real-time control algorithms and codes that guarantee sufficient control performance (spatial-temporal closed-loop bandwidths);
• Demonstrate closed-loop operations in a lab experiment where the real-time computations are performed at the required speed but the wavefront sensor camera and the deformable mirror are operating at a significantly lower speed.

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