Robust Compensator Synthesis for Antiwindup Design with Coprime Factor Uncertainties

This paper studies the antiwindup synthesis problems for plants with coprime factor uncertainties. The proposed technique utilizes an equivalent framework of compensated systems to investigate the robustness of the antiwindup compensators. The penalty operators of the input saturation are studied originally in general cases. Robustness criteria are proposed for an antiwindup compensated system with different model uncertainties including the additive uncertainty and the coprime factor uncertainties. Linear matrix inequality based techniques can synthesize an antiwindup compensator to conform the system to better robustness requirements for input saturation problems. The simulation results show that the antiwindup compensator synthesized in this paper is more adequate to plants with coprime factor uncertainties. A system which is a rotorcraft model in hover flight condition is presented as a practical example to show the robustness and the performance of the antiwindup compensator from the proposed approach.