A multiple periodic disturbance rejection control for process with long dead-time

Most of industrial processes have dead-time phenomenon that will affect the process performance. Though there are some disturbance rejection methods for the process with dead-time, however, most of them may not work well for multiple periodic disturbance. In this paper, a novel periodic disturbance rejection controller is designed based on the Smith predictor platform for process with long dead-time. By adding two feedback loops and the online spectrum analysis, multiple periodic disturbances can be suppressed effectively in existence of long dead-time. The rigorous analysis is conducted to prove that the robust stability can be maintained. Finally, the effectiveness of the proposed controller is demonstrated in the process simulations and industrial experiment. © 2014 Elsevier Ltd.