MATLAB: “Glitches” in transfer function

bodeplotMATLABtransfer function

Hi all,

I was developing a certain model which includes a lot of transfer functions, which are mainly 2×2 matrices. There is a fair deal of multiplication and division of these transfer function as well. I have noticed that in some of them I have sort of "glitches" which I have no idea how to avoid and correct. Have you seen similar behaviour or, even better, you have a solution for it? Below is the what I obtain when I draw the transfer function with "bodeplot" command

Best Answer

Precision could certainly be a problem, especiall considering the magnitudes of those numbers. (MATLAB retains full internal precision, even though the printed output is much less precise.)

See if using the minreal function helps.

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MATLAB: Setting nonlcon for fmincon / patternsearch as a matlabfunction

Create a wrapper function like the one below. To make it visible from the workspace where patternsearch is called, you can make it a local function or a nested function in the same file, rather than placing it in a separate mfile. Pass the function handle generated by matlabFunction to the wrapper as a fixed parameter:

cFun=matlabFunction(vertcat(eqn_nonlin-1,-eqn_nonlin+0.8));
nonlcon = @(a) nonlconWrapper(a,cFun); 
a_optimal = patternsearch(fun,a_Initial,A,b,Aeq,beq,lb,ub, nonlcon  );
function [c,ceq]=nonlconWrapper(a,cFun) %This can be a local function
   aCell=num2cell(a);
   c=cFun(aCell{:});
   ceq=[];
   
end

MATLAB: I want to find the determinant for 5.5 matrix

>> syms s1 s2 s3 s4 s5 s6 s7 s8 s9 s10
>> M = [0 -s1 -s2 -s3 -s4; s1 0 -s5 -s6 -s4; s2 s5 0 -s8 -s9; s3 s6 s8 0 -s10; s4 s7 s9 s10 0];
>> det(M)
ans =
s1*s4^2*s8^2 - s1*s4*s7*s8^2 - s2*s4^2*s6*s8 + s3*s4^2*s5*s8 - s3^2*s4*s5*s9 - s2^2*s4*s6*s10 + s3^2*s5*s7*s9 + s2^2*s6*s7*s10 + s2*s3*s4*s5*s10 + s2*s3*s4*s6*s9 + s1*s2*s4*s8*s10 - s1*s3*s4*s8*s9 - s2*s3*s5*s7*s10 - s2*s3*s6*s7*s9 + s2*s4*s6*s7*s8 - s3*s4*s5*s7*s8 - s1*s2*s7*s8*s10 + s1*s3*s7*s8*s9
>> simplify(ans)
ans =
(s4 - s7)*(s3*s5 - s2*s6 + s1*s8)*(s2*s10 - s3*s9 + s4*s8)

Best Answer

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MATLAB: Setting nonlcon for fmincon / patternsearch as a matlabfunction

MATLAB: I want to find the determinant for 5.5 matrix

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