Digital Control of dc motor question advice

MrAl

Joined Jun 17, 2014
13,761
Dear MrAL et al.,

In these couple of weeks, I tried to tackle my last part of the assignment and I asked into similar control forums about my question with no avail. I did some found out on several books describing root locus in discrete-time and I attempt to answer it. But I am not fully confident of my working, so I am asking to someone to verify my method (PDF attached) and suggest any correction to rectify my working if necessary.

Thank you for your continuous support,

Saviour
I can take a look at this but one question, what is that "plus and minus" sign in the exponent for?
 

Thread Starter

Saviour Muscat

Joined Sep 19, 2014
187
Hello again,


To be clearer, I did simulation in MATLAB using sisotool of the G, which is nearly the desired result, please see the attached image
compensator D(z)=(z-0.7586)/(z-0.6985)

Open loop factorized (with compensator D(z)), G(z) = (0.4458 *(0.04) (z-0.7586) (z + 0.675)/(z-0.6985) (z− 1) (z− 0.584) (z− 0.563))

Thank you very much,

matlabcode
close all;
clc;
T=0.1;
numerator=[0.04,0,0.027];
denominator=[1, -2.14676325, 1.475347016, -0.328616078];
G=tf(numerator,denominator,0.1);
sisotool(G);
 

Attachments

MrAl

Joined Jun 17, 2014
13,761
Hello again,


To be clearer, I did simulation in MATLAB using sisotool of the G, which is nearly the desired result, please see the attached image
compensator D(z)=(z-0.7586)/(z-0.6985)

Open loop factorized (with compensator D(z)), G(z) = (0.4458 *(0.04) (z-0.7586) (z + 0.675)/(z-0.6985) (z− 1) (z− 0.584) (z− 0.563))

Thank you very much,

matlabcode
close all;
clc;
T=0.1;
numerator=[0.04,0,0.027];
denominator=[1, -2.14676325, 1.475347016, -0.328616078];
G=tf(numerator,denominator,0.1);
sisotool(G);
So you are getting the response you wanted already?
 

Thread Starter

Saviour Muscat

Joined Sep 19, 2014
187
Hi,

Required dominant poles position(dynamics) = 0.792 +- 0.172j , required wn=3rad/s, zeta=0.7

simulation results, dominat pole position(dynamics) 0.181+-161j, zeta=0.698, wn=2.74rad/s

what do you think, of these results? are they good?

1666453325084.png
 

MrAl

Joined Jun 17, 2014
13,761
Hi,

Required dominant poles position(dynamics) = 0.792 +- 0.172j , required wn=3rad/s, zeta=0.7

simulation results, dominat pole position(dynamics) 0.181+-161j, zeta=0.698, wn=2.74rad/s

what do you think, of these results? are they good?

View attachment 279088
I would have to go over all your work and that may take some time as i am also involved in several other things at the moment some not even related to electrical stuff.
In the mean time you can show the label for your 'y' axis on the plot.
 

Thread Starter

Saviour Muscat

Joined Sep 19, 2014
187
Dear MrAL,
Thank you for your help and goodwill,
Yesterday I submitted my assignment as it is.
Again, thank you and I appreciate help
Saviour
 
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