Sub-nanometer active seismic isolator control

G. Balik (1) , B. Caron (2) , J. Allibe (1) , A. Badel (2) , J.-P. Baud (1) , L. Brunetti (1) , G. Deleglise (1) , A. Jérémie (1) , R. Le Breton (2) , S. Vilalte (1)

1 LAPP - Laboratoire d'Annecy de Physique des Particules
2 SYMME - Laboratoire SYstèmes et Matériaux pour la MEcatronique

Ambitious projects such as the design of the future Compact Linear Collider (CLIC) require challenging parameters and technologies. Stabilization of the CLIC particle beam is one of these challenges. Ground motion (GM) is the main source of beam misalignment. Beam dynamics controls are however efficient only at low frequency (<4Hz), due to the sampling of the beam at 50 Hz. Hence, ground motion mitigation techniques such as active stabilization are required. This paper shows a dedicated prototype able to manage vibration at a sub-nanometer scale. The use of cutting edge sensor technology is however very challenging for control applications as they are usually used for measurement purposes. Limiting factors such as sensor dynamics and noise lead to a performance optimization problem. The current state of the art in GM measurement and GM mitigation techniques is pointed out and shows limits of the technologies. The proposed active device is then described and a realistic model of the process has been established. A dedicated controller design combining feedforward and feedback techniques is presented and theoretical results in terms of Power Spectral Density (PSD) of displacement are compared to real time experimental results obtained with a rapid control prototyping tool.

Domaines: Génie mécanique [physics.class-ph]; Génie mécanique [physics.class-ph]; Vibrations [physics.class-ph]; Vibrations [physics.class-ph]

G. Balik, B. Caron, J. Allibe, A. Badel, J.-P. Baud, et al.. Sub-nanometer active seismic isolator control. Journal of Intelligent Material Systems and Structures, 2013, 24 (15), pp.1785-1795. ⟨10.1177/1045389X13500571⟩. ⟨in2p3-00864796⟩