Revisiting Ziegler-Nichols. A fractional order approach

Area of Science:

• Control Engineering
• Automation Systems
• Signal Processing

Background:

• Proportional-Integral-Derivative (PID) controllers are widely adopted in industrial automation.
• Traditional auto-tuning methods like Ziegler-Nichols have limitations, prompting ongoing research for improvements.
• Fractional-order PID (FOPID) controllers offer enhanced performance but require specialized tuning techniques.

Purpose of the Study:

• To introduce a novel auto-tuning method specifically designed for fractional-order PID controllers.
• To leverage the fractional order to shape the loop frequency response for optimized tuning.
• To demonstrate superior closed-loop performance compared to existing standard methods.

Main Methods:

• A new auto-tuning technique is proposed for FOPID controllers.
• The method involves shaping the direction of the loop frequency response at the critical Ziegler-Nichols point.
• The fractional order is utilized as a key parameter for this shaping process.

Main Results:

• The proposed method achieves better closed-loop performance in numerical simulations.
• Validation through diverse case studies confirms the method's effectiveness.
• Demonstrated advantages over the standard Ziegler-Nichols tuning approach for FOPID systems.

Conclusions:

• The novel auto-tuning method offers a significant advancement for fractional-order PID controller tuning.
• Shaping the frequency response using fractional order is a viable strategy for performance enhancement.
• The method provides a practical and effective solution for industrial automation challenges.