Autotuning PID Control for Large Time-Delay Processes and Its Application to Paper Basis Weight Control

Abstract

The brief arts and crafts of the ordinary fourdrinier are introduced first in this paper. After analysis of the intractable points of paper basis weight (BW) control, an autotuning PID/PI control algorithm is then presented which is capable of controlling large time-delay processes. The algorithm can be described as below. The oscillation amplitude and frequency induced by a modified relay feedback identification method at the point where the Nyquist curve of the process intersects the negative imaginary axis in the S plane are obtained. In terms of the information obtained above, the autotuning PID/PI parameter values are thus tuned according to the specified robust specifications of amplitude and phase margin. The algorithm has many advantages such as simple parameter adjustment, little dependence on the process model, strong robustness, and ease of implementation. It is also very suitable for controlling industrial processes such as the BW loop with large time delay.