A New Approach for QFT-type Robust Controller Design in Uncertain Multivariable Systems

This paper presents a robust controller design methodology for a class of linear uncertain multivariable systems with hard time-domain constraints on their outputs and control signals in response to step disturbance inputs. In this approach, the m×m MIMO system is replaced by m2 SISO systems and then, using the QFT technique, desirable controllers are synthesized. The final controller will be diagonal and since its entries are designed separately with suitable bandwidths, an economic design can be achieved. The application of this new method will be demonstrated through an example.