Model Prediction-Based Approach to Fault Tolerant Control with Applications

Abstract— Fault-tolerant control (FTC) is an integral component in industrial processes as it enables the system to continue robust operation under some conditions. In this paper, an FTC scheme is proposed for interconnected systems within an integrated design framework to yield a timely monitoring and detection of fault and reconfiguring the controller according to those faults. The unscented Kalman filter (UKF)-based fault detection and diagnosis system is initially run on the main plant and parameter estimation is being done for the local faults. This critical information\ud is shared through information fusion to the main system where the whole system is being decentralized using the overlapping decomposition technique. Using this parameter estimates of decentralized subsystems, a model predictive control (MPC) adjusts its parameters according to the\ud fault scenarios thereby striving to maintain the stability of the system. Experimental results on interconnected continuous time stirred tank reactors (CSTR) with recycle and quadruple tank system indicate that the proposed method is capable to correctly identify various faults, and then controlling the system under some conditions

Active Fault Tolerant Control System in Sensors and Actuators: Application in a Distillation Column

[EN] This work presents the simulation results of an active fault tolerant control system on a distillation column. The aim of the control system is to maintain the binary distillation process (ethanol-water) in continuous operation even if both sensors or actuator fault occurs. To develop the active fault tolerant control system, it was designed a fault detection and diagnosis system by using a full-order high-gain observer to estimate the temperatures and concentrations on the distillation column; the estimation of the temperatures and concentrations was made by using only one measured temperature. Also, there were employed three adaptive observers, one is used to estimate the vapor pressure, the other two observers are used to estimate a parameter in each actuator, in that way is estimated the size, instant and magnitude of the fault. The active fault tolerant system is based on the compensation of the fault based on the information given by the fault detection and diagnosis system. The fault tolerant in sensor is based in the reconfiguration of the faulty sensor. The main contribution of this work is that proposed scheme is able to detect and diagnosis, multiple and simultaneous failures in sensors and at least in one actuator. The simulation test shows that the control law allows that the liquid molar concentrations required in distillates, follow the reference properly, even in presence of faults.[ES] En este trabajo se presentan los resultados en simulación de un sistema de control tolerante a fallas activo (CTFA) aplicado a una columna de destilación. El sistema de control tiene como objetivo mantener el proceso de destilación binaria (etanol-agua) en operación con y sín la presencia de fallas en sensores o actuadores. El CTFA se desarrolló a partir de un sistema de detección y diagnóstico de fallas empleando un observador de alta ganancia de orden completo para estimar las concentraciones no medidas de la columna de destilación, dicho observador estima todas las concentraciones de la columna de destilación a partir de una sola temperatura medida. Así mismo, se emplearon tres observadores adaptativos para estimar la presión de vapor y los parámetros de los actuadores; de tal forma que es posible determinar el tipo, instante de aparición y magnitud de la falla. El control tolerante a fallas en actuadores se basa en la compensación de la ley de control utilizando la información del sistema de detección y diagnóstico de fallas. El control tolerante a fallas en sensores se basa en la reconfiguración del elemento con falla. La principal contribución que se presenta en el artículo es el sistema CTFA, el cual es capaz de mantener al sistema de control operando aun con la presencia de fallas múltiples y simultáneas en sensores y por lo menos en un actuador. Las pruebas en simulación muestran que la ley de control permite que las concentraciones molares líquidas requeridas en los productos destilados sigan la referencia de manera adecuada aun en presencia de fallas.Ortiz Torres, G.; Escobar, R.; Adam Medina, M.; Astorga Zaragoza, C.; Guerrero Ramírez, G. (2016). Control Tolerante a Fallas Activo en Sensores y Actuadores: Aplicación a una Columna de Destilación. Revista Iberoamericana de Automática e Informática industrial. 13(1):67-79. https://doi.org/10.1016/j.riai.2015.05.006OJS6779131Agudelo, C., Anglada, F. M., Cucarella, E. Q., & Moreno, E. G. (2013). 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