Past Issues

Studies in Informatics and Control
Vol. 28, No. 4, 2019

Stabilizing High-order Delayed Systems with Minimum-phase Zeros Using Simple Controllers*

C. D. Vázquez Rosas, J. F. Márquez Rubio, B. del Muro Cuéllar, D. F. Novella Rodríguez, O. Sename3, L. Dugard
Abstract

This paper analyses the stabilization and control of delayed processes systems containing minimum phase zeros. The high-order delayed process taken into consideration consists of: one unstable pole and m minimum phase zeros. Sufficient conditions are provided in order to guarantee the existence of a stabilizing basic controllers: Proportional (P), Integral (I) and Derivative (D), i.e., P, PI, PD and PID controllers. The frequency domain approach is used to proof the main results. Additionally an optimal H∞ tuning of the controller is proposed. The adequateness of the obtained results are tested by simulation through the implementation of a continuously stirred-tank reactor model.


*This paper is an extended version of the work titled “Stability condition for unstable high-order system with minimumphase zeros plus time-delay”, published in the Congreso Nacional de Control Automático (AMCA) 2017 (Vázquez et al. 2017). Employing a different method for the proof, the current paper presents improved sufficient conditions for P/PI controllers in order to stabilize the process taken into consideration. Another novel element is the sufficient condition to guarantee the existence of stabilizing PD/PID controllers. Finally the theory is employed in order to tune the parameters for the PI/PID controllers.

Keywords

Zeros, Unstable processes, Time-delay, Stabilization.

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