Independent design of decentralized controllers for specified closed-loop performance

The paper presents an original frequency domain approach to decentralized controller design for specified performance The novelty of the proposed approach consists in assessing the influence of interactions by means of characteristic functions/loci of the plant interaction matrix, and further using them to modify mathematical models of subsystems thus defining the so called “equivalent subsystems”. The independent design carried out for equivalent subsystems provides local controllers that guarantee fulfilment of performance requirements without any deterioration due to the effect of interactions. Theoretical conclusions are supported with results obtained from the solution of several examples, one of which is included.