AN EFFICIENT ALGORITHM FOR COMPUTING QFT BOUNDS

An important step in Quantitative Feedback Theory(QFT) design is the t ranslation of closed-loop performance specifications into QFT bounds. These bounds, domains in a Nichols chart, serve as a guide for shaping the nominal loop response. Traditionally, QFT practitioners relied on manual manipulations of plant templates on Nichols charts to construc t such bounds, a tedious process which has recently been replaced with numerical algorithms, However; since the plant template is approximat ed by a finite number of points, the QFT bound computation grows expon entially with the fineness of the plant template approximation As a re sult, the designer is forced to choose between a coarse approximation to lessen the computational burden and a finer one to obtain more accu rate QFT bounds. To help mitigate this tradeoff this paper introduces a new algorithm to more efficiently compute QFT bounds. Examples are g iven to illustrate the numerical efficiency of this new algorithm.