QFT design for uncertain non-minimum phase and unstable plants revisited Wen-Hua Chen Donald J. Ballance 2134/3858 https://repository.lboro.ac.uk/articles/journal_contribution/QFT_design_for_uncertain_non-minimum_phase_and_unstable_plants_revisited/9227108 Design method for uncertain non-minimum phase and unstable plants in the Quantita- tive Feedback Theory (QFT) developed by Horowitz and Sidi (Horowitz and Sidi, 1978; Horowitz, 1992) is revisited in this paper. It is illustrated that the existing method may not work since some design rules have not been clearly speci¯ed by several exam- ples including non-minimum phase plants and unstable plants. Then stability of a new nominal plant is carefully examined and analysed, and an improved design method is presented. The result in this paper provides mathematical justi¯cation of the QFT de- sign procedure for non-minimum phase and unstable plants in Horowitz and Sidi (1978) and Horowitz (1992). 2008-11-03 16:37:19 Robust Control Frequency Domain Quantitative Feedback Theory (QFT) Non-minimum Phase System Unstable Systems Robust Stability Mechanical Engineering Engineering not elsewhere classified