MATLAB: Error while running a loop inside transfer function

MATLABmatlab transfer function error loop for tf

i'm trying to change the value of k from to 0.1:0.1:7 and when i try this i get this error

??? Error using ==> InputOutputModel.subsasgn at 58
Subscript indices must either be real positive integers or logicals.
Error in ==> spect at 7
G(k)=tf([k],[10*10^-3 1]);

my code:

for k=0.1:0.1:7;
G(k)=tf([k],[10*10^-3 1]);
end

how can i fix that?

Best Answer

You are trying to assign the value of the tf() call into G(k) when k is not an integer. Subscripts must be positive integers.

kvals = 0.1 : 0.1 : 7;
for kidx = 1 : length(kvals)
  k = kvals(kidx);
  G(kidx) = tf([k],[10*10^-3 1]);
end

Related Solutions

MATLAB: How to acces and change value inside transfer function inside a loop

Kobi, I tried running your code and got an error message. It looks like you missed a space between G.den{1,1} and (k) in the line GG=tf([G.num{1,1}],[G.den{1,1} (k)]);

Is this the problem?

MATLAB: Index in position 1 is invalid. Array indices must be positive integers or logical values. Error in pid_optimized1 (line 17) solution(K,:) = [K a m ts];

You are using K as a logical indexer, but K take non positive integers values, throwing, then, an error. I gues that the solution is:

t = 0:0.01:8;
k = 0;
for K =3:0.2:5
    for a = 0.1:0.1:3
        num = [4*K 8*K*a 4*K*a^2];
        den = [1 6 8+4*K 4+8*K*a 4*K*a^2];
          y = step(num,den,t);
          s = 801;while y(s)>0.98&&y(s)<1.02;s = s-1;end
        ts = (s-1)*0.01;%ts = settling time;
        m = max(y);
        if m < 1.15 && m > 1.10
            if ts<3.00
               k = k + 1;
               solution(k,:) = [K a m ts]; %this sorts the solution of K a m ts in a column array
            end
        end
    end
end

Best Answer

Related Solutions

MATLAB: How to acces and change value inside transfer function inside a loop

MATLAB: Index in position 1 is invalid. Array indices must be positive integers or logical values. Error in pid_optimized1 (line 17) solution(K,:) = [K a m ts];

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