A μ-synthesis approach to guaranteed cost control in track-following servos

摘要

This paper presents a new control synthesis approach for dual-stage track-following servo systems with multi-rate sensing and actuation. For these systems, the robust track-following problem can be formulated as a periodic time-varying guaranteed cost control problem. To reduce the conservatism of the guaranteed cost control framework, uncertainty scalings such as those used in the D-K iteration heuristic for μ-synthesis are introduced. Although this results in a non-convex optimization problem, it is shown that it lends itself to a methodology similar to D-K iteration. Using this methodology, a controller is designed for a set of hard disk drives which minimizes the worst-case l_2 semi-norm performance of the system.