Two-level numerical procedure for optimal design of digital modal controllers

The problem of optimal modal synthesis of digital controllers is considered. The goal is to minimize a cost function over the set of controllers that place closed-loop poles in a specified region D. A two-level numerical optimization procedure is developed for design of optimal reduced-order modal controllers. An important feature of the method is that the original cost function is not modified. For the case of a quadratic cost function, a new method of optimization over polynomials is developed on the basis of a Diophantine equation.