ABSTRACT
Quantitative feedback theory (QFT)∗ is a very powerful design technique for the achievement of assigned performance tolerances over specified ranges of structuredplant parameter uncertaintieswithout andwith
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control effector failures [9]. It is a frequency domain design technique utilizing the Nichols chart (NC) to achieve a desired robust design over the specified region of plant parameter uncertainty. This chapter presents an introduction to QFT analog and discrete design techniques for both multiple-input singleoutput (MISO) [1,5,13] and multiple-input multiple-output (MIMO) [3,4,6,7,10-12] control systems. QFT computer-aided design (CAD) packages are readily available to expedite the design process. The purposes of this chapter are (1) to provide a basic understanding of QFT; (2) to provide the minimum amount of mathematics necessary to achieve this understanding; (3) to discuss the basic design steps; and (4) to present a practical example.
