Decoupling control based on H∞-mixed sensitivity problem

In this paper, decoupling control with state feedback and output feedback based on the H_∞-mixed sensitivity problem is presented. Decoupling performance in state feedback control is obtained by choosing the weighting functions properly. This is shown by clarifying the structure of the state feedback gain and the solution of the Riccati equation. Next, decoupling performance in output feedback control is shown by using the fact that the closed loop transfer matrices in state feedback and output feedback designed for the same weighting functions are same. Furthermore, an example of a ship motion control system is shown to demonstrate decoupling performance of the proposed design