Automatic tuning of nonlinear PID controllers for unsymmetrical processes

Abstract

Relay auto-tuning of linear PID regulators is now a proven technology in process control industry. In this paper, it is extended to auto-tune nonlinear PID controllers for unsymmetrical processes. Two sets of PID parameters each for one operating mode are obtained with a single relay experiment. Excellent performance of the auto-tuned nonlinear control system is substantiated by simulations.