A survey of template generation methods for quantitative feedback theory

One of the main assumptions of quantitative feedback theory (QFT) is that the uncertainty in the plant that is being controlled can be quantified in some way. This is most often achieved by the use of a transfer function with parameters that vary in some way. Typically the parameters will vary within given ranges and thus the overall transfer function will vary within an envelope or template. This paper reviews the work of a number of authors, presents the algorithms required to calculate the templates, and considers the assumptions made in the calculations and discusses the advantages and disadvantages of the different approaches.