control.margin

control.margin(sysdata)

Calculate gain and phase margins and associated crossover frequencies

Parameters

sysdata (LTI system or (mag, phase, omega) sequence) –

sysStateSpace or TransferFunction

Linear SISO system

mag, phase, omegasequence of array_like

Input magnitude, phase (in deg.), and frequencies (rad/sec) from bode frequency response data

Returns

• gm (float) – Gain margin

• pm (float) – Phase margin (in degrees)

• wg (float) – Frequency for gain margin (at phase crossover, phase = -180 degrees)

• wp (float) – Frequency for phase margin (at gain crossover, gain = 1)

• Margins are calculated for a SISO open-loop system.

• If there is more than one gain crossover, the one at the smallest

• margin (deviation from gain = 1), in absolute sense, is

• returned. Likewise the smallest phase margin (in absolute sense)

• is returned.

Examples

>>> sys = tf(1, [1, 2, 1, 0])
>>> gm, pm, wg, wp = margin(sys)