allmargin - All crossover frequencies and corresponding stability margins

Syntax

S = allmargin(sys) s = allmargin(mag,phase,w,ts)

Description

S = allmargin(sys)

allmargin computes the gain, phase, and delay margins and the corresponding crossover frequencies of the SISO open-loop model sys. allmargin is applicable to any SISO model, including models with delays.

The output S is a structure with the following fields:

GMFrequency — All -180 degree crossover frequencies (in rad/s)
GainMargin — Corresponding gain margins, defined as 1/G where G is the gain at crossover
PMFrequency — All 0 dB crossover frequencies in rad/s
PhaseMargin — Corresponding phase margins in degrees
DMFrequency and DelayMargin — Critical frequencies and the corresponding delay margins. Delay margins are given in seconds for continuous-time systems and multiples of the sample time for discrete-time systems.
Stable — 1 if the nominal closed-loop system is stable, 0 otherwise.

In general, stability cannot be assessed for FRD system. In any case when stability cannot be assessed, S is set to NaN.

s = allmargin(mag,phase,w,ts) computes the stability margins from the frequency response data mag, phase, w, and the sampling time, ts. allmargin expects frequency values w in rad/s, magnitude values mag in linear scale, and phase values phase in degrees. Interpolation is used between frequency points to approximate the true stability margins.

allmargin - All crossover frequencies and corresponding stability margins

Syntax

Description

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