QFT Design for Uncertain Nonminimum Phase and Unstable Plants
نویسندگان
چکیده
Design of robust controllers for uncertain non-minimum phase and unstable plants with the Quantitative Feedback Theory (QFT) is addressed in this paper. Several counterexamples including non-minimum phase plants and unstable plants are given to illustrate the errors in Horowitz and Sidi method 7, 5]. It is shown that the stability requirement of the new nominal plants is misused or ignored in the existing design method. The stability requirement for the new nominal plant is reformulated and improved design methods for nonminimum phase and/or unstable plants are presented.
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