step function gives Error using step Not enough input arguments.

I want to make a simulation of a plant, I wrote this code but it throws this error: Error using step Not enough input arguments.

% Define the transfer function of the plant

num_p = [13];

den_p = [1 -1/13];

p = tf(num_p, den_p);

% Define the transfer function of the controller

num_c = [40/13];

den_c = [1 (1/13 + 0.2) (0.2/13)];

c = tf(num_c, den_c);

% Find the transfer function of the closed-loop system

cl = feedback(p, c);

amplitudes = 20:5:60;

t = 0:0.01:100;

figure;

for i = 1:length(amplitudes)

amplitude = amplitudes(i);

input_signal = amplitude * step(t);

[y, t_out] = lsim(cl, input_signal, t);

plot(t_out, y);

hold on;

end

xlabel('Time (s)');

ylabel('Output (y)');

title('Response');

legend(num2str(amplitudes'));

Answer 1

[Fangjun Jiang]

Not the correct way to use step(). It is used to get the step response of a system, not to get the step input signal.

You can use step() in replace of lsim(). Look at the examples in "doc step".