Where can I find definitions for gain margin, phase margin, and stability margin?
Submitted by: asa Submitted on: November 14, 2004 Identifier: L7.1 Look in section 7.4, pages 177 and 178 of the textbook, for these definitions. [Back to Top] • How do I calculate “steady state error”? Submitted by: asa Submitted on: November 14, 2004 Identifier: H6 There is no direct Matlab command to calculate the steady state error. However, if you look at the block diagram for our standard PC feedback loop, you’ll see that the error is the input to the control block. You should then be able to calculate a transfer function H_{er} very straightforwardly. Think a bit about “steady state” and you’ll see what value of s you need to evaluate this at to get the steady state error. Also, if you know the final value theorem, and think about the final value of H_{er} for a step input, you should get the same answer. Note, however, that this analysis requires that the system is stable — if it’s not stable, then there is no limit for the final value, and “steady state error” isn’t defined.
