Design of a Self-Tuning PID Controller and its Application for a Polymerizing Reactor

PID control schemes based on classical control theory, have been widely applied to real control systems. There have been lots of works on tuning PID parameters, since the control performance strongly depends on these parameters. Several self-tuning and auto-tuning PID techniques have been reported for systems with unknown or slowly time-varing parameters. None, however, is applicable to discrete-time system with an unknown dead time. In this paper, a self-tuning PID control algorithm is proposed based on the relationship between the PID control law and the generalized minimum variance control law which is one of self-tuning control strategies. The proposed control scheme is practically evaluated on a temperature control system of a polybutene reactor.