How to make an automated and updated legend for ts step response graph

Hi all,

I have developed a scrpit that can calculate step respons for any specified DE.

However, for the legends, it always returns the titles as Fs1.

I wish for the script to return the legend as the range including c1 to c2.

For example:

if c1 = 0

c2 = 5

the legend would show the titles as

c = 0

c = 1

c = 2

c = 3

c = 4

c = 5

Below is the code designed

clear;

close all;

clc;

%% Setting values for the DE %%

I = input("Input value for the numerator in the form [x y z]"); % Sets Numerator Value %

m = input("Input the desired value for m for the denominator of (ms^2 + cs + k)"); % Sets the m value of the Denominator %

c1 = input("Input lowest value of the damping term c"); % Sets the lowest value of the Damping variable c %

c2 = input("Input highest value of the damping term c"); % Sets the highes value of the Damping variable c %

c = c1:c2; % Creates variable c as a (x,y) vector, allowing for multiple damping coeffectients to be used %

k = input("Input the desired value for k for the denominator of (ms^2 + cs + k)"); % Sets valuefor k in the Demoninator of the DE %

%% Calculation and Graphing of DE %%

for j = 1:length(c) % Sets for loop for all damping coefficient variables %

Fs1 = tf([I], [m c(j) k]); % tf calculation using pre-defined variables %

step(Fs1,10) % creates step graph using all values calculated, the time domain is set to 10 seconds for optimisation %

hold on; % holds all data within the loop %

end

hold off % cancels the hold on loop after all values have been saved %

legend

Answer 1

[Star Strider]

The Control System Toolbox plots are characteristically difficult to work with.

The best option would be:

[y,tOut] = step(Fs1,10);

and then:

figure

plot(tOut, y, 'DisplayName',sprintf('c = %.3f,'c))

or something similar for each parameter variation you are using. Use the hold function to plot different step outputs to the same axes.

With more information or specific data, I could provide a more specific example. As is, I am not certain what result you want.

[Kez]

so the idea was to have it compile on a single graph like this:

entering the parameters when running the code gives you the figure above (just enter the number and press enter).

value of numerator: 1

value of m: 1

lowest c value: 0

highest c value : 20

value of k: 25

I was hoping to adjust the legend format such that it will always list the lowest c value and increase by increments of 1 until the highest c value is reached.

So chosing the lowest c value as 4 and the highest as 6 would range the legend as

c = 4

c = 5

c = 6

with all three lines present on a single graph

whilst if i enered the lowest value of c as 0 and the highest as 10, the graph would have all 11 lines on it with the legend as follows

c = 0

c = 1

c = 2

c = 3

c = 4

c = 5

c = 6

c = 7

c = 8

c = 9

c = 10

I hope this is a bit clearer.

Thank-you for your time and support.

[Star Strider]

This incorporates my changes for the plot and legend, subscripting the ‘c’ values in the plot call and using the 'DisplayName' name-value pair.

I changed ‘c2’ to 5 for convenience —

%% Setting values for the DE %%
% I = input("Input value for the numerator in the form [x y z]"); % Sets Numerator Value %
% m = input("Input the desired value for m for the denominator of (ms^2 + cs + k)"); % Sets the m value of the Denominator % 
% c1 = input("Input lowest value of the damping term c"); % Sets the lowest value of the Damping variable c %
% c2 = input("Input highest value of the damping term c"); % Sets the highes value of the Damping variable c %
I = 1; m = 1; c1 = 0; c2 = 5; k = 25;       % <— DELETE LATER
c = c1:c2; % Creates variable c as a (x,y) vector, allowing for multiple damping coeffectients to be used % 
% k = input("Input the desired value for k for the denominator of (ms^2 + cs + k)"); % Sets valuefor k in the Demoninator of the DE %
%% Calculation and Graphing of DE %%
hold on
for j = 1:length(c) % Sets for loop for all damping coefficient variables %
Fs1 = tf([I], [m c(j) k]); % tf calculation using pre-defined variables %
[y,tOut] = step(Fs1,10);
plot(tOut, y, 'DisplayName',sprintf('c_{%3d} = %3d',j,c(j)))
% step(Fs1,10) % creates step graph using all values calculated, the time domain is set to 10 seconds for optimisation %
% hold on; % holds all data within the loop %
end
hold off
hold off % cancels the hold on loop after all values have been saved %
legend('Location','eastoutside') 

Make appropriate changes to get the result you want.

.

[Kez]

Thank-you so much for your help.

[Star Strider]

As always, my pleasure!