Feedback Function Not enough input arguments error

So here is my code below when I run it it gives me a error which should not happen. Any suggestions as to what to do inorder to fix this small error? I own all of packages required. It should just work.

syms s

k=0.0223; theta=60; Tau=12.6;

kc=3.75; TauD=0; TauI=12.6;

G=(k*exp(-theta*s))/(Tau*s+1)

C=kc*(1+1/(TauI*s)+TauD*s)

sys = feedback(G*C,1);

step(sys)

Answer 1

[Star Strider]

Please do not mix Symbolic Math Toolbox and Control System Toolbox commands.

It only confuses both of them!

k=0.0223; theta=60; Tau=12.6;
kc=3.75; TauD=0; TauI=12.6; 
s = tf('s');                                            % ,— ADD THIS ASSIGNMENT
G=(k*exp(-theta*s))/(Tau*s+1) 

G =
 
                 0.0223
  exp(-60*s) * ----------
               12.6 s + 1
 
Continuous-time transfer function.

C=kc*(1+1/(TauI*s)+TauD*s)

C =
 
  47.25 s + 3.75
  --------------
      12.6 s
 
Continuous-time transfer function.

sys = feedback(G*C,1);
step(sys)

.

[Victor Jimenez Carrillo]

This was very helpful. You are loved!!!

[Star Strider]

Thank you!

.

Answer 2

[Walter Roberson]

feedback() does not accept symbolic expressions.