Abstract
In this article, we treat robust stability design of decoupling controllers for the plant with multiplicative-type uncertainty. We show that the robust stability condition in terms of matrix H ∞-norm leads to interpolation problems on scalar functions and we derive the relative degree conditions on the interpolating scalar functions to guarantee the properness of resulting controllers. Nevanlinna–Pick algorithm with relative degree constraints is presented to solve the interpolation problems with the relative degree constraints.
Acknowledgements
This work was supported by National Research Foundation of Korea under the contract number 313-2008-2-D00325. The authors thank the reviewer for his suggestions and comments which helped improve this article.