A new algorithm for self tuning of proportionalintegral-
derivative (PID) controllers is proposed. A combined
least-squares estimation and Newton–Raphson search technique
is used to determine the ultimate gain and period of an unknown
system for the purpose of automatic tuning of PID controllers
based on Ziegler and Nichols (ZN) or refined Ziegler and Nichols
(RZN) formulas. The proposed algorithm can be applied to systems
with known time delay, as well as those with unknown dead
time. Simulation studies are used to demonstrate the performance
of this algorithm. The performance of this PID self tuner is also
compared with a popular commercial auto-tuner for simulated
systems and a laboratory-scale real plant.
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