Based on the conventional structure of internal model control (IMC), a
novel IMC scheme with enhanced robustness is developed in this paper.
The necessary structure modification for robustness enhancement is ve
ry simple as well as effective, and the synthesis of the additional co
mponents is not only very simple but also independent from the design
of the original IMC controller. Both analytical and numerical studies
have been presented to demonstrate the contribution of the structure m
odification to the robustness enhancement of IMC systems.