Robust control system design in frequency domain

In this paper two robust control methods for hybrid system are presented. Both methods are usefull for SISO and MIMO systems. Controller design procedure is developed in frequency domain. Equivalent subsystem method is used for controller design in this paper. Stability condition of proposed methods bases on small gain theory and uses additive and inverse additive model type. Two tank water system is presented in the paper and serves as a numerical example to compare effectiveness of described methods.