title: How do I obtain the step response of this PID controller in Matlab?
body: <p>I'm relatively new to Control systems. I'm trying to obtain a graph for the step response of a PID controller of the form 
      <img src="https://i.stack.imgur.com/dOXtn.png" alt="enter image description here"> </p>
  
  <p>Is this possible to plot in mat lab because I get the error that the function cannot plot the step response of a system with more poles than zeros. 
  Is there any way to plot this system without the whole infinity issue so that I can observe the characteristics of its step response?
  I'm sorry if I'm asking a dumb question that may seem obvious but any help or explanation would be greatly appreciated.</p>
  
  <p>This is my mat lab code for my PID controller:</p>
  
  <pre><code>%3.PID Control,Td=0.001, 0.01, 0.05, 0.1
  a=tf([0 0 -10],[0 1 10]);
  b=tf([0 -1 -5],[1 3.5 6]);
  kc=5;
  Ti=1;
  Td=0.001;
  k1=tf([0 Td 0],[0 0 1]);       %derivative control
  k2=tf([0 1],[Ti 0]);            %integral control
  G=kc*(k1+k2+1);                % the controller
  G1=series(a,b);
  y=feedback(G,G1,-1);
  subplot(2,2,1),stepplot(y),title('kc=5,Ti=1,Td=0.001');
  </code></pre>