DISE˜NO DE UN ESQUEMA OBSERVADOR CONTROLADOR PARA LA ESTABILIZACI´ON DE SISTEMAS CON RETARDO Y CON DOS POLOS INESTABLES

Abstract

In engineering, many reactions of the system to external actions do not take place instantaneously. This phenomena is linked with propagation and transport of energy or material, and systems that present this feature are so-called time delay systems. Time delays are useful to model engineering systems, biological systems, economic systems, etc., they are also used to approximate high order systems to reduced order systems with time delay. Delays represent a challenge because they are often source of oscillations, instability and bad performance Many works have been developed in last years in order to analyze the stability and design control strategies for time delay systems. This thesis introduce a simple control strategy in order to stabilize second order systems with two unstable poles plus time delay. Necessary and sufficient conditions for the existence of this stabilizing control scheme are stated. Moreover, the proposed control structure is used to stabilize different kind of systems with two unstable poles, (high order systems and systems with a stable zero). Finally a robustness analysis is presented in order to compute the maximum uncertainty bound of the delay term. Numerical simulations are presented to illustrate the proposed control strategy performance, demonstrating a satisfactory response. The robustness analysis is studied by mean of numerical simulations also. The control strategy proposed is implemented on electronic plants built with operational amplifiers, proving its performance against parametrical variations due to the use of comercial electronic devices.