Non-sequential QFT Design Methodology for Disturbance Rejection Problem in Uncertain Multivariable Systems

Abstract

A new design approach for quantitative feedback synthesis (QFT) to the disturbance rejection problem in an uncertain multi-input multi-output (MIMO) linear time-invariant system is proposed. The proposed method is centered on converting the problem on uncertain system into a nominal system and the uncertainties are transferred as a output disturbances whose range is known. In particular, we derive the controller bounds for each of the equivalent nominal single-input single-output (SISO) problems. The proposed non-sequential approach is attractive as it brings simplicity and less conservative than an existing independent SISO method. The effectiveness of the proposed approach is illustrated via challenging MIMO systems with both parametric and non-parametric uncertainty. The proposed solution is less conservative than the existing design which leads to reduced feedback cost.