Revisiting Ziegler-Nichols. A fractional order approach

PID controllers are largely used in industry. Auto-tuning methods for these controllers have emerged over the years, including the well-known Ziegler-Nichols method. Several extensions and improvements to this early autotuning method have been proposed throughout the years. A new method is introduced in this manuscript suitable for fractional order PIDs. The direction of the loop frequency response in the critical Ziegler-Nichols point is shaped using the the fractional order. The numerical results show that better closed loop performance is achieved. Different case studies are considered to validate the proposed method and demonstrate its advantage compared to the standard method. (C) 2022 ISA. Published by Elsevier Ltd. All rights reserved.

Automated summary

PID controllers are widely used in industry, and various auto-tuning methods have been developed. This manuscript presents a new method for fractional order PIDs, which improves closed loop performance. Numerical results and case studies demonstrate its advantages.