Timeline for Why are the phase indicators different between the open loop bode plot and the closed loop bode plot?
Current License: CC BY-SA 4.0
6 events
| when toggle format | what | by | license | comment | |
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| Feb 24, 2023 at 1:35 | comment | added | zymaster | I posted the question in here: engineering.stackexchange.com/questions/54369/… | |
| Feb 23, 2023 at 19:09 | comment | added | TimWescott | "... there are at least two gain margins for Type III systems ..." This was something that I figured out on the job, although it's something that you could work out as a homework problem in a course on dynamic control. Feel free to ask a question just about this topic; if I don't answer it chances are that someone else will. | |
| Feb 23, 2023 at 19:03 | comment | added | TimWescott | I have worked with systems where the plant was very close to an integrator ($H(s) = 1/(\tau s + 1)$, with $\tau$ very large compared to any closed-loop system dynamics), and the controller was double-integrating ($G(s) = (b_2 s^2 + b_1 s + b_0) / s^2$). In such a system, the starting point is 270 degrees of phase lag or nearly so -- and they can be stabilized just fine. | |
| Feb 23, 2023 at 6:29 | comment | added | zymaster | Besides, you said "This is the case even in the case for a system that starts out with more than 180 degrees of lag", Do you means that systems exist where the lag in the starting position is 180° and are still stable? | |
| Feb 23, 2023 at 6:10 | comment | added | zymaster | Thank you very much for your answer, I don't quite understand why you said there are at least two gain margins for Type III systems, is there any information or web links you can provide, I need to learn about it. | |
| Feb 20, 2023 at 21:39 | history | answered | TimWescott | CC BY-SA 4.0 |