Single-loop stability margins for multirate and periodic control systems

It is shown how to compute the stability margin of periodic systems with respect to compatible periodic perturbations of such systems. It is suggested that the nonstandard time-invariant model for periodic systems introduced by the author (Syst. Contr. Lett., vol.17, pp.9-14, 1991) leads to a simpler computation, although the standard model gives the same result.<
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