Why Unrecognized function or variable 'set_point'?

clear;clc;close all;
A = [0 1 0 ; 0 -10 7.5; 0 -0.15 2];
B = [0;0;2];
C = [1 0 0];

J = [-5 -5 -5];

K = acker(A,B,J);

KK = [0 K(2) K(3)];

k1 = K(1);

sim('simulation_of_dc_motor_control')

sp = set_point(:,1);
y = angular_position(:,1);
t = time_data(:,1);

figure
hold on;grid on;
plot(t,sp,t,y,'linewidth',2)
legend('set point','angular position')

stepinfo(y,t,sp(1))
sse = abs(sp(end)-y(end));
fprint('Steady State Error = %d \n',sse);

Hi, i've some trouble here, Here is my code, i got error "Unrecognized function or variable 'set_point'."

I make the simulink before and try to connect it to my script but i think it doesnt connect well.

Here is my block in simulink

How to solve it?

Thanks

[Walter Roberson]

Is that a To Workspace block? Or are you logging the signal?

I suggest for debugging you use

out = sim('simulation_of_dc_motor_control');
whos
fieldnames(out)

[Yusuf Hamzah]

i want to try find angular position dc motor control using state feedback

[Walter Roberson]

What output did you get when you use the debugging steps that I suggested?

Answer 1

[Fangjun Jiang]

The variable that you are looking for, "set_point",is in "out.set_point".

So, in your code, replace "set_point" with "out.set_point". You may also need to change it to "out.set_point.Time" and "out.set_point.Data" because the data is not saved as "Array" but "timeseries".

This is impacted by settings at "Configuration Parameters", "Data Import/Export". The "Single simulation output" must have been checked so the "To Workspace" block variable automatically becomes "out.set_point".

If you use sim(), you need to give it a return variable like, xyz=sim('ModelName'), then your variable is in "xyz.set_point".

The "Data Import/Export" has been changed quite a lot from old days. Play with it manually first to figure it out and then write your code.