Output feedback finite frequency H∞ control for SISO singularly perturbed systems

In this paper, a controller for the singularly perturbed system is designed in detail to satisfy frequency-domain loop-shaping specifications which are given in terms of H_infin norm, moreover, the controller has the similar structure with the full system. It is further shown that this controller is obtained through designing its fast and slow parts. The main contribution of this paper is that the controller can be constructed directly without the composition of the sub-optimal controllers. The effectiveness of the proposed method is demonstrated through comparing with traditional H_infin design method.