Relay feedback PID auto-tuning: algorithm and application

摘要

Describe a PID auto-tuning algorithm based on relay feedback. By placing test signals on the process to make it surge stably and continuously, we can obtain the process data with which to calculate the critical gain and critical surge period, then proper PID parameters can be computed with the improved Ziegler-Nichols formula. Some software based on this algorithm has run successfully on some large industrial equipment for over 7 years.