A new approach to automatic PID tuning: The large ζ tuning method

Proportional-integral-derivative (PID) controllers still represent the majority of the controllers used in industry today due to their effectiveness, robustness, low cost, and easy implementation. A properly designed and well tuned PID controller works well in many systems and processes. Therefore, automatic tuning of PID controllers has attracted great attention ever since their invention. This paper presents a new approach to the automatic tuning of PID controllers - the large ζ tuning method. This relatively simple tuning method can guarantee the desired maximum overshoot and rise time by tuning only one parameter. Simulations have been carried out for lower and higher order linear systems, timedelayed systems, and some nonlinear systems. Results have shown that this large ζ tuning method is also effective on systems with time-varying parameters. Comparisons among three methods, the popular Ziegler-Nichols method, the internal model control (IMC) method, and the large ζ tuning method indicate that the proposed method performs as well as (if not better than) the other two methods. Also, it provides smaller controller gains in general, and acts as a closed-loop tuning method. Therefore, the large ζ tuning is a new closed-loop tuning method that offers a simple and effective way for automatic tuning of PID controllers, and is competitive to other existing self-tuning methods.