Robust performance design of multivariable control systems

The paper presents an iterative approach for the robust performance design of basically noninteraction multivariable control (BNIC). Compared with the improved quantitative feedback theory (QFT) methodology, the present approach is attractive for two reasons; (i) the degree of overdesign can be successively reduced by iteration, and (ii) disc gain bounds are used in the problem formulation such that, in the BNIC problem, the diagonal elements of T(s) are minimum phase. An illustrative example is given to show the superiority of the present approach over the improved QFT technique for BNIC plants or plants that can be reduced to BNIC by precompensation