Multiobjective control for multivariable systems with mixed-sensitivity specifications

A series of multiobjective H design problems are considered in this paper. The problems are formulated as a number of coupled H design problems. These H problems can be formulated as sensitivity problems, complementary sensitivity problems or control sensitivity problems for every output (or input) in the system. It turns out that these multiobjective H design problems, based on a number k of different types of sensitivity problem, can be exactly decoupled into H k sensitivity problems for stable systems, where is the number of outputs (for unstable systems, independent stabilization is required). Further, it is shown how similar techniques can be used to incorporate simultaneous specifications for l different control objectives such as H, etc., for the sensitivities. The approach 2 1 is illustrated by an experimental set-up for a steel mill test rig.