Systematically Structured $H_2$ Optimal Control for Truss-Supported Segmented Mirrors

A systematic distributed optimal control design procedure is proposed for the rejection of wind load-induced disturbances on a truss-supported segmented mirror. The distributed nature of the controller is achieved by weighing of the interaction matrices between local (per-segment) controllers in a global H
₂
optimization. The procedure allows a tradeoff analysis between the controller implementation complexity versus the improved performance the extra communication brings. The procedure is demonstrated on a finite element model of a segmented mirror on a flexible supporting truss to which we apply the combined closed-loop performance and local controller interconnection structure optimization. The resulting set of controllers is compared to a set of baseline controllers including linear-quadratic-Gaussian control, singular value decomposition control, and a distributed controller where local controllers of neighboring segments communicate. The tradeoff analysis for the segmented mirror demonstrates that the communication between the local controllers can be greatly reduced without significantly compromising the rejection of wind-induced wavefront errors.