Function or variable 'rscale' not recognised.

A = [ 0   1   0 
    980  0  -2.8 
    0   0  -100 ];
B = [ 0 
    0 
    100 ];
C = [ 1 0 0 ];
poles = eig(A)

poles = 3×1

31.3050 -31.3050 -100.0000

t = 0:0.01:2;
u = zeros(size(t));
x0 = [0.01 0 0];
sys = ss(A,B,C,0); 
[y,t,x] = lsim(sys,u,t,x0); 
plot(t,y) 
title('Open-Loop Response to Non-Zero Initial Condition') 
xlabel('Time (sec)') 
ylabel('Ball Position (m)')

p1 = -10 + 10i; 
p2 = -10 - 10i; 
p3 = -50; 
K = place(A,B,[p1 p2 p3]); 
sys_cl = ss(A-B*K,B,C,0); 
lsim(sys_cl,u,t,x0); 
xlabel('Time (sec)')
ylabel('Ball Position (m)') 

p1 = -20 + 20i; 
p2 = -20 - 20i; 
p3 = -100; 
K = place(A,B,[p1 p2 p3]); 
sys_cl = ss(A-B*K,B,C,0); 
lsim(sys_cl,u,t,x0); xlabel('Time (sec)') 
ylabel('Ball Position (m)')

t = 0:0.01:2; 
u = 0.001*ones(size(t)); 
sys_cl = ss(A-B*K,B,C,0); 
lsim(sys_cl,u,t); xlabel('Time (sec)') 
ylabel('Ball Position (m)')
axis([0 2 -4E-6 0])

Nbar = rscale(sys,K) 

Unrecognized function or variable 'rscale'.

Function or variable 'rscale' is not recognised by matlab. I get an error like this.

https://ctms.engin.umich.edu/CTMS/index.php?example=Introduction&section=ControlStateSpace

However, the url above has this code description. How can I use it?

Answer 1

[Rik]

As it says right on that page:

"Note that this function is not standard in MATLAB. You will need to download it here, rscale.m, and save it to your current workspace."

[hemsas kamel]

Cà marche.

Answer 2

[Pavl M.]

clc
clear all
close all

A = [ 0   1   0 
    980  0  -2.8 
    0   0  -100 ];
B = [ 0 
    0 
    100 ];
C = [ 1 0 0 ];
D = [0];

poles = eig(A)

poles = 3×1

31.3050 -31.3050 -100.0000

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ts = 0.001;
sys = ss(A,B,C,D,ts); 
G = ss2tf(sys.A,sys.B,sys.C,sys.D)

G = 1×4

0 0 0 -280

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p1 = -20 + 20i; 
p2 = -20 - 20i; 
p3 = -100; 

K = place(sys.A,sys.B,exp(ts*[p1 p2 p3]))

K = 1×3

10.0301 -3.5098 -1.0286

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%In place of separate function invokation, faster
s4 = size(sys.A,1);
Z = [zeros([1,s4]) 1];
N = (1\([sys.A,sys.B;sys.C,sys.D]))*Z';
Nx = N(1:s4);
Nu = N(1+s4);
Nbar=Nu + K*Nx

Nbar = -102.8648

%

opts = hinfsynOptions('Display','on');
W1 = makeweight(100,[1],0.25,ts);
W3 = makeweight(0.25,[1],100,ts);
%W2 = makeweight(0.01,[0.1],1,ts);
figure
bodemag(W1,[],W3)

P = augw(sys,[],[],W3)

P =
 
  A = 
           x1      x2      x3      x4
   x1  0.9018       4       0       0
   x2       0       0       1       0
   x3       0     980       0    -2.8
   x4       0       0       0    -100
 
  B = 
        u1   u2
   x1    0    0
   x2    0    0
   x3    0    0
   x4    0  100
 
  C = 
           x1      x2      x3      x4
   y1  -2.329    95.1       0       0
   y2       0      -1       0       0
 
  D = 
       u1  u2
   y1   0   0
   y2   1   0
 
Input groups:       
    Name    Channels
     U1        1    
     U2        2    
                    
Output groups:      
    Name    Channels
     Y1        1    
     Y2        2    
                    
Sample time: 0.001 seconds
Discrete-time state-space model.

%ncont = 1; % one control signal, u
%nmeas = 2; % 1 measurement signals
%[K,CL,gamma] = hinfsyn(P,ncont,nmeas,opts)
%contact me more if want this to study more interactively and to complete.