IEEE Transactions on Automatic Control, Vol.47, No.12, 2117-2121, 2002
Analytic stability margin design for unstable and nomninimum-phase plants
This note is concerned with the problem of designing controllers for unstable and nonminimum-phase plants according to stability margin criteria. First, an elementary technique to achieve a satisfactory tradeoff between phase and gain margin is presented. Then, it Is shown how to derive from the controller thus obtained other controllers that make either margin (almost) twice as large. The procedures perform well in terms of both computational complexity and controller order.