Model-based Autotuning System Using Ann and Relay Feedback Test

A model-based autotuning system is presented for PI/PID controllers. A conventional relay feedback test is used to generate the response for estimations of parameters such as: process gain, ultimate gain, ultimate frequency, and apparent deadtime. Two ANNs are built based on the data generated from standard SOPDT processes to enhance the estimation of apparent deadtime. Upon having the estimated results, the dynamics of the process is classified into one of two groups. In one group, PI/PID controller will be tuned based on the FOPDT parameterization. In the other group, only PID controller will be considered for dynamic control, and the controller will be tuned according to the SOPDT parameterization. The tuning rules are given in terms of ultimate gain, ultimate frequency, and the apparent deadtime. Since the tuning rules are derived from model-based control, they are superior to the Z-N rules in performance.