“…For example, the continuous time PID controller is expressed in the Laplace domain as q 2 (s) = K P 1 + 1 Tis + T d s , where K P is the proportional gain, T i and T d are the integral and derivative time constants. Furthermore, many process control problems also contain a time delay τ m (see O'Dwyer, 2006;Morarescu, Mendez-Barrios, Niculescu & Gu, 2011). These include proportional plus delay q 3 (s), integrator plus delay model q 4 (s), first order lag plus delay q 5 (s), first order lag plus integral plus delay q 6 (s) expressed below: If in the expression of q 3 (s) there are two different gains for the two terms, then we obtain the proportional retarded controller: q 7 (s) = K p + K r e −sτm .…”