For problem 1, do we plot bode and nyquist plots for the open-loop or closed-loop system?
Submitted by: waydo Submitted on: November 14, 2004 Identifier: H6 We always generate these plots for the open-loop system. One of the remarkable things about these plots is that the open-loop plots can be used to tell us everything we will need to know about the closed-loop system. [Back to Top] • 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,
