On Self-Tuning Control of Processes with Time Varying Dead Time

This paper addresses the lack of robustness in the design of a classic self-tuning controller (STC); in particular the poor performance demonstrated if the time delay of the process is time varying. To avoid these problems, the implementation of a novel practical self-tuning controller (PSTC) is described. The PSTC employs plant excitation with a PRBS to ensure good model estimates, a process monitor to determine when the estimator should be turned off, and an outer loop "intelligent" integrator. Simulation results are presented for a third order benchmark process model and a second order model of the steam temperature system in a coal-fired boiler.