E-ELT primary mirror control system

Abstract

During the past year the control of the 42m segmented primary mirror of the E-ELT has been studied. This paper presents the progress in the areas of M1 figure control and control hardware implementation. The critical issue of coupling through the supporting structure has been considered in the controller design. Different control strategies have been investigated and from a tradeoff analysis modal control is proposed as a solution addressing the topics of wind rejection as well as sensor noise in the presence of cross-coupling through the supporting structure. Various implementations of the M1 Control System have been studied and a centralized architecture has been selected as baseline. This approach offers maximum flexibility for further iterations. The controller design and main parts of the control system are described.