Quantitative Feedback Theory (QFT)

Abstract

In QFT, the feedback design problem has always been that of achieving defined performance over specified range of plant uncertainty, with minimum "cost of feedback". Eigenvalue realization was always considered an incidental problem. Two benchmark problems are presented. The first is a 2×2 highly uncertain nonlinear plant. The second is a 3×7 digital (60 Hz) flight control problem with uncertainty consisting of 36 possible effector failure cases with no failure detection and identification, i.e. a fixed compensation design. Both problems were solved by QFT with satisfactory results.