[Octave-bug-tracker] [bug #41154] Rlocus function axis graduation not optimal

[anonymous]

URL:
  <http://savannah.gnu.org/bugs/?41154>

                 Summary: Rlocus function axis graduation not optimal
                 Project: GNU Octave
            Submitted by: None
            Submitted on: Wed 08 Jan 2014 10:15:12 PM UTC
                Category: Octave Forge Package
                Severity: 3 - Normal
                Priority: 5 - Normal
              Item Group: Performance
                  Status: None
             Assigned to: None
         Originator Name: Saul Mtakula
        Originator Email: address@hidden
             Open/Closed: Open
         Discussion Lock: Any
                 Release: 3.6.4
        Operating System: Microsoft Windows

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Details:

The code down below generates a root locus (control 2.4.2) with axis
graduations that are not clear especially compared to results from Matlab or
Scilab. The attached screenshot illustrates what I mean.


clear
clc
pkg load control
s = tf('s');
% Polynomial seed
Gain1 = (s^2+20*s+100)/(s^2+6*s+100);
Gain2 = Gain1*(s^2+3*s+220)/(s^2+25*s+225);
Gain3 =(s+5)/(s*s*(s-2000)*(s-200)*(s-25)*(s-1));
Gain4 = 352*Gain3;
%
%Bode plot:
%---------------
subplot(221)
bodemag(Gain2,Gain1,0.01,100)
% Magnitude plot
%
%Nyquist plot:
%-------------------
subplot(222)
nyquist(Gain2,Gain1)
% Plot with Re and Im axes
%Nichols chart (Black's diagram + iso-plots):
%-------------------------------------------------------------
subplot(223)
nichols(Gain2,Gain1,0.01,100)

%
%Evans root locus:
%-------------------------
subplot(224)
rlocus(Gain4) %,0100) %,100)
% Evans root locus for sys4




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File Attachments:


-------------------------------------------------------
Date: Wed 08 Jan 2014 10:15:12 PM UTC  Name: octave_root_locus.png  Size:
193kB   By: None

<http://savannah.gnu.org/bugs/download.php?file_id=30227>

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