Optimization of Linear Parameterizable ℋ∞ Controllers in the Frequency Domain

Abstract In this paper a novel approach for ℋ ∞ controller design for linear parameterizable controllers is presented. The approach uses the generalized Nyquist stability criterion to find the parameters of linear parameterized controllers for Multi-Input Multi-Output (MIMO) systems. The main advantage of the proposed approach is that the generalized plant does not have to be diagonally dominant and that there is no need for a desired open-loop response function. By constraining the Nyquist curve from certain parts in the frequency domain, controller parameters that guarantee stability and performance of the closed-loop system can be found. The method is successfully applied to two cases involving a double-mass-spring-damper system. In the first case only controller parameters are optimized and in the second case both structural and controller parameters are optimized.