A Generalized Loop-Shaping Technique for Design of Multivariable Feedback Control Systems

In this paper, we develop a loop-shaping method to deal with various uncertainty descriptions for robust control design. The applicability of the method to the case of structured perturbations is discussed. The block sensitivity in the M-Δ structure is exploited, yielding bounds on the structured singular value. These bounds help us develop an interactive design strategy for various controller modifications to shape the blocks of M matrix that have the largest impact on μ.