Internal model control for structured rank deficient system based on full rank decomposition

In this paper, an internal model control method is first proposed for structured rank deficient systems based on full rank decomposition. The system is first converted into a column full rank system by designing a pre-compensator. Then a feedback-compensator is designed to improve the dynamic characteristics of the full rank system and decrease the controller design difficulties. Rather than performing complex designing calculations, the pre- and feedback- compensators are designed by the full rank decomposition method. Furthermore, the non-square relative gain subsystem selection criterion is used to choose the square subsystem and to realize loop pairing. Consequently, the selected square subsystem is used as an internal model to design the internal model controller. Finally, a simple process is taken as the simulation object to demonstrate the validity and feasibility of the new method. Simulations results illustrate that the proposed strategy is not only simple and easy to implement but also has a good performance even the system model is mismatched.