Time delay filter design for the non-minimum phase systems

A new proportional and derivative (PD) type time delay filter, which utilizes the time-delay effect, is first applied to a non-minimum phase system. It can stabilize an unstable system using delayed feedback, and also quickly response to input changes. Furthermore, it is shown that a conventional P-controller equipped with an appropriate time-delay unit performs an average derivative action, and is therefore insensitive to high-frequency noise. The simulation results demonstrate the effectiveness of this PD type time delay filter