How does overshoot relate to phase margin?
Submitted by: haomiao Submitted on: November 21, 2004 Identifier: H7 You can approximate the system as a 2nd order system by looking at the 2 dominant poles. Note that since poles on the real axis do not contribute to oscillatory behavior, they have no effect on the phase margin. Then, using the equations shown in Wednesday’s lecture, you can get a requirement for the damping ratio zeta. Zeta is related to the phase margin through a somewhat complicated formula, which we can approximate to the linear relationship zeta is roughly PM/100. [Back to Top] • Is it OK for a system to have infinite gain margin? Submitted by: waydo Submitted on: November 22, 2004 Identifier: H7 Absolutely. This just means that the phase never crosses -180, and we can turn up the gain as much as we like without causing instability (although in the real world turning up the gain too much will still lead to problems). [Back to Top] • Isn’t the sensitivity function the same as the function used for steady state err
