Tracking substrate trajectories in continuous aerobic wastewater reactors via nonlinear PI controllers

 

Aguilar-Lopez, R.¹, Neria-Gonzalez, Ma. I.² & Soto-Corte, G.

 

¹ Departamento de Energía, Universidad Autónoma Metropolitana-Azcapotzalco, Av. San Pablo No. 180, Reynosa-Tamaulipas, 02200; Azcapotzalco, México D.F., México. E-mail: raguilar@correo.azc.uam.mx Fax: + (52) 5394 7378.

² Departamento de Microbiología Escuela Nacional de Ciencias Biológicas-IPN.

 

Received: September 1^th, 2005.
Accepted: January 26^th, 2006.

 

Abstract

This work addresses the problem of robust tracking of the substrate concentration in a continuous bioreactor in an industrial wastewater treatment plant of an oil refinery. The entire nonlinear operating region of the process was approached by several linear models. The suggested global controller is designed considering an average between the linear single controllers designed for each operating region. The averaging methodology is conducted via interpolation, considering Gaussian distributions as the interpolating functions. The robust properties of the global controller are shown by employing a Lyapunov function. The corresponding performance of the proposed methodology is illustrated via numerical simulations.

Keywords: Reactor Modelling, Simulation, Averaged Controller, Robust Performance, Tracking.

 

Resumen

En este trabajo se presenta el problema de seguimiento robusto de la trayectoria de referencia de la concentración de sustrato en un bioreactor de una planta industrial de tratamiento de agua residual de una industrial de refinación de petróleo. Mediante varios modelos lineales, se aproxima la región completa de operación de la planta. Se sugiere un controlador global considerando para su diseño un promedio entre los controladores lineales previamente diseñados para cada región de operación modelada por su correspondiente aproximación lineal. La metodología para promediar los controladores individuales es realizada tomando como funciones interpolantes las distribuciones gausianas. La robustez de la metodología propuesta es mostrada mediante un análisis de estabilidad de Lyapunov. El desempeño del esquema de control propuesto se muestra por medio de simulaciones numéricas.

 

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