MATLAB Answers


Simulink model 'to workspace' output

Asked by Mohsina Zafar on 4 Jul 2019
Latest activity Answered by Jesús Zambrano on 12 Oct 2019
I am trying to control motor torque and am using a workspace variable in Simulink and want to output similar variable to workspace.
I have size(T_u)=[3, 91] whereas the output I am getting from the simulation has size [101, 90]
I am unable to understand why this is so.
Code that I am using:
t = 1:0.1:10;
T_o = [0.05*(10-t);0.04*(10-t);0.03*(10-t)];
T_d = zeros(size(T_o));
T_e = (T_d - T_o);
C_PD = pid(100,0,10,100);
T_u = zeros(size(T_e));
for k=1:size(T_e,1)
T_u(k,:) = lsim(C_PD,T_e(k,:),t);
T_l = zeros(size(T_u));
C_PI = pid(10,1000,0);
a = sim('Motor_Control','SimulationMode','normal');
out = a.get('T_l')
.mat and .slx files are attached.


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1 Answer

Answer by Jesús Zambrano on 12 Oct 2019

Hi Mohsina,
I see T_u matrix is loaded in you model using the From Workspace block. In this case each row of the matrix has time stamp in the first column, and the data in the rest of columns. In this particular example the data takes 90 columns. Then, the simulation runs using a variable step solver, it means that the step size varies from step to step, and it will depend on the model dynamics. You can see this variation when plotting
Hope this answers your question.


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