Numerical Optimization of Electroactive Actuator Position for Optical Mirror Applications

K. THETPRAPHI1, V. BRUYERE2, D. AUDIGIER1, J.F. CAPSAL1, P. NAMY2, G. MORETTO3
1Univ Lyon, INSA-Lyon, LGEF, EA682, F-69621, Villeurbanne, France
2SIMTEC, 5 rue Felix Poulat, GRENOBLE, FRANCE
3Centre de Recherche Astrophysique de Lyon (CRAL), 9 avenue Charles André, 69230 Saint-Genis-Laval, France
Published in 2023

Electroactive actuators are widely used in precision optical systems to control the position and shape of optical elements, such as telescope mirrors. However, the optimal position of the electroactive actuator for a given optical mirror design is not obvious, and numerical optimization techniques can be employed to find the optimal solution. To control the local curvature of the mirror and to define the objective to minimize in the optimization procedure, a first distributed ODE is implemented. In a second step, a mechanical model is developed to compute the mirror displacement as a function of the force applied by the piezoelectric actuators. Finally, an optimization procedure is used to minimize the local curvature by controlling the intensity and distribution of the electromechanical force. The optimized results show a strong interest in the use of this technology to minimize the initial defects related to the manufacturing of the mirror or the defects during use related to the gravity creep.