Design of robust PI controller by combining robustness regions with time-domain criteria

This paper describes the design of a robust PI controller by considering several design criteria simultaneously (multi-objective optimization). Firstly, all controllers satisfying multiple frequency domain criteria (e.g. sensitivity function limits) are found in PI parameter plane using robustness regions method. Then, all suitable controllers are evaluated by the selected time-domain criterion, for example: Integral Error (IE), Integral of Time-weighted Absolute Error (ITAE) etc. Further, application of H 2 and H ∞ norms is shown in that context. The whole design toolchain is supported by advanced Matlab GUI which was used in the illustrative example. The described approach can be extended for PID controllers as well, for development of advanced autotuners and for teaching and training purposes.