A Delay-type Pid Controller

This paper presents a delay-type PID controller (shortened as dPID) or a PID controller which is implemented using two delay elements. The gains are analytically tuned; one of the delay is optimally tuned and the other one is chosen to be equal to the sampling time. The poles of the discrete version of the dPID controller lies inside the unit circle and far away from the point . Hence, it is stable and ripple-free. This controller is then applied to a first-order model plus dead-time (FOPDT), which can represent the majority of typical industrial processes; it achieves much better performances than the classical PID controller.Copyright c 2002 IFAC