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1.What is the meaning of demon = [1 3 1]?
2.What is the meaning of Gp=tr(num,demon)?
3.How to interpret this line:
M=feedback(Gp,H)
This is a website address for this PIC control:
https://www.bilibili.com/video/BV1Aq4y1U7bg?from=search&seid=281292339855222775&spm_id_from=333.337.0.0
Thanks
1 Comment
Walter Roberson
on 26 Mar 2022
you miscopied. The code does not use tr(), it uses tf()
Control systems are often expressed as transfer functions, each deals with derivatives. The higher the power of s you see, the higher the derivative. The overall expression is the laplace transform of the time function.
Answers (1)
Sam Chak
on 26 Mar 2022
Edited: Sam Chak
on 26 Mar 2022
Hi @Chris Yang
It is actually not "demon", but "denom", a shortened form of the word "Denominator". A Demon generally means an evil spirit or devil, whereas the denominator is the part below the fraction line:
.
- The line denom = [1 3 1] creates a horizonatal vector of numbers with 3 elements in it. These numbers are actually coefficients for that will be used for creating the transfer function model later. Similarly, num = [1] creates the coefficient for in the numerator (the part above the fraction line).
- The line Gp = tf(num, denom) creates the transfer function model for the Plant (a control theory term that stands for a dynamical system to be controlled).
- The line M = feedback(Gp, H) creates the closed-loop transfer function that loops around the the feedforward transfer function and the feedback transfer function . The transfer function commonly relates the reference input to the output . Since there is only one feedforward element, (no controller ), then the formula is given by .
Hope the explanations help. Also suggest you to take these TWO (2) short courses:
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