Robustness characteristics and optimal robust tuning of a 2DOF PI control for an uncertain IPDT plant

A comparison of different two degree of freedom (2DOF) PI controller tuning methods [1] in control of an integral plus dead time system (IPDT) showed significant advantages of the new tool for an optimal and robust tuning based on the performance portrait method. The presented analysis will now be further extended by considering uncertainties of both plant parameters and by derivning robustness characteristics of the corresponding closed loops expressing influence of a parameter uncertainty on a chosen performance measure under specified shape requirements.