A new double sided frequency weighted problem formulation

In this paper, the solution to controller reduction problem for systems with a feedback controller via a double-sided frequency weighted model reduction technique is considered. A new method with a fast algorithm for finding low order controllers is proposed. This algorithm is based on new frequency weights derived using closed-loop system approximation criterion. The formulas of frequency weights are obtained in terms of the plant, the original controller and a free parameter. By varying the free parameter in the resulting two-sided frequency weighted model reduction problem, frequency weighted error can be significantly reduced to yield more accurate low-order controllers.