This paper shows that the first step in the design of multivariable controllers within the Characteristic Locus Method must be the design of a static normalizing precompensator that makes the pre-compensated plant as closely as possible to a normal matrix at the vicinity of the crossover frequency, if robustness is to be addressed in a later stage of the design. Following this conclusion, the design of a static normalizing pre-compensator with no constraint in its structure is presented, being

more »

... ased on an optimization problem whose solution can be obtained directly by solving a simple eigenvalue problem. A numerical example illustrates the efficiency of the proposed design strategy.