Robust decentralized controller design in frequency domain

The paper presents control system design based on robust decentralized control. Controller design will be done in the frequency domain for nominal model with time delay. Robust condition ensuring stability also by delay change, based on M-delta structure is included in controller design. In controller design for multivariable systems equivalent subsystem method is used. For subsystems of equivalent model, frequency method ensuring desired phase margin and crossover frequency is applied. Design procedure is illustrated on example and compare conservativism by using of different characteristic functions.