Non-Smooth Multi-Objective Controller Synthesis for Test-Mass Actuation in Gravitational-Wave Detectors

This paper proposes a non-smooth controller optimization method and shows the results of ongoing research on the implementation of this method for gravitational-wave applications. Typical performance requirements concerning these type of suspensions are defined in terms of both H2- and H∞-type constraints. A non-smooth optimization approach is investigated, which allows the use of non-convex cost functions that are often a result of mixed H2/H∞ optimization problems. Besides the controller, the distribution of the actuation is integrated with the optimization to investigate the feasibility of simultaneous controller and actuator optimization. The results demonstrate that the proposed non-smooth optimization method is able to find suitable solutions for the control and actuator distribution that satisfy all required performance and design constraints.