Higher-Order Derivative Compensators as a Better Alternative to PID in Controlling the Systems with Higher Dynamics

N. Mir-Nasiri (Malaysia)


Derivative compensators, Tuning rules, Stability, Steadystate, Transient


The paper introduces the design and computer simulation of the new PDN controller. It is suggested as an alternative to the traditional PID controller The PID is still popular as an industrial process controller. PDN controller is as simple as PID but it is more effective when dealing with higher-order dynamic systems. Its higher-order derivative gains/compensators (KN, KN-1,…, K1, K0) are able to improve transient performance of the system. In other words, they are able to directly control values of higher-order dynamic components of the system under control. The compensators urge the system to be stabile and respond much faster than in case of using PID controller. One of the components of the PDN controller is a tunable command feed-forward steady state gain (KS) that forces the system to attain the selected set point value or track the selected time varying input command. It helps to track the input commands much faster and more precisely than it could be achieved by using the integral component of the PID controller. The theory in the paper covers the steady state performance, stability issues, and the controller gains tuning strategies to improve the transient responses of the feedback system. The advantages of the PDN controller are thoroughly analyzed and demonstrated by solving the set point input (step) and the tracking a time varying input (ramp) problems. The paper also presents the detailed instructions for selecting and tuning the higher-order derivative compensators of PDN controller for the general case of unknown order stable/unstable plant and particular case of unknown order but stable plant.

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