Bounded positive adaptive control for counterflow heat exchangers

"In this work, we propose an outlet temperature control scheme for counterflow heat exchangers, that takes into account and actually exploits the analytical-stability features inherent to the open-loop dynamics. As a result, outlet temperature regulation is achieved through a simple adaptive controller which does not need to feedback the whole state vector and does not depend on the exact value of the system parameters. Furthermore, positivity and boundedness (nonsaturation) of the input flow rate are additionally guaranteed through the proposed approach, without entailing complex control algorithms or stability proofs. The analytical developments are corroborated through experimental results.

A generalized design methodology for the output feedback regulation of a special type of systems with bounded inputs

"In this work, a generalized design scheme for the output feedback regulation of a special type of systems with bounded inputs is proposed. It gives rise to a simple dynamic controller that guarantees the regulation objective avoiding input saturation, for any initial condition within a specific set that may comprehend the whole state space and that does not require any additional system data (apart from the output variable). Several processes, like double?pipe heat exchangers, bioreactors, and binary distillation columns, are shown to be part of the type of systems that may be regulated through the developed methodology. The efficiency of the proposed scheme is corroborated through experimental and simulation results.

Instrumentation of a bicycle without driver for experimental testing of automatic control

"In this paper, the instrumentation of a riderless bicycle prototype for control purposes is addressed. The proposed instrumentation is based on the mathematical model of a bicycle, in which the dynamical variables correspond to the translational velocity, the angular position of the handlebar and the velocity of the roll angle of its general framework. Throughout the paper, a convenient and simple way to measure these variables is detailed explained, in order to provide an instrumented prototype ready to be used for testing automatic control laws. This corresponds to the main contribution of the present paper. The dynamical model from which the proposed instrumentation has been designed, corresponds to a Linear Parameter Varying system, considering the translational velocity as time-varying parameter. The results of the instrumentation and its effectiveness are shown from experimental tests.

A bounded positive nonlinear PI controller for double-pipe heat exchangers

"In this work, temperature regulation of double-pipe heat exchangers is considered. The positive (unidirectional) and bounded features of the flow rate input variable are taken into account in the analysis. As a result, a bounded positive PI-type control scheme, which achieves the regulation objective avoiding input saturation, is proposed. It turns out to be a simple algorithm that does not need to feed back the whole state vector, that does not depend on the exact value of the system parameters, and whose stabilization character is global in the closed-loop system state-space domain. Moreover, it may be applied to both flow configuration cases, i.e., countercurrent and parallel-flow heat exchangers. The analytical developments are corroborated through experimental and simulation results.

State and actuator fault estimation observer design integrated in a riderless bicycle stabilization system

"This paper deals with an observer design for Linear Parameter Varying (LPV) systems with high-order time-varying parameter dependency. The proposed design, considered as the main contribution of this paper, corresponds to an observer for the estimation of the actuator fault and the system state, considering measurement noise at the system outputs. The observer gains are computed by considering the extension of linear systems theory to polynomial LPV systems, in such a way that the observer reaches the characteristics of LPV systems. As a result, the actuator fault estimation is ready to be used in a Fault Tolerant Control scheme, where the estimated state with reduced noise should be used to generate the control law. The effectiveness of the proposed methodology has been tested using a riderless bicycle model with dependency on the translational velocity v, where the control objective corresponds to the system stabilization towards the upright position despite the variation of v along the closed-loop system trajectories.

Synthèse d’observateurs fonctionnels à temps de convergence finie

National audienceCet article présente un observateur fonctionnel pour des systèmes linéaires et un estimayeur de fautes en convergence en temps fini. La stabilité de l'observateur est presentée et sa performance est demontréeà partir de similations numeriques. L'originalité de cet observateur fonctionnel est sa capabilité de convergir en un temps donné et garantir la correcte estimation de la faute en une periode précise de temps

Design and implementation of an observer-based soft sensor for a heat exchanger

The objective of this work is to describe step-by-step how to implement an observer-based soft sensor in order to estimate process variables for which a hardware sensor is not available. The design and implementation procedure is illustrated by applying it to a counter-flow double-pipe heat exchanger. The approach used to design the nonlinear observer is based on a simplified mathematical model of the process. Numerical simulations and experiments were performed in a bench-scale pilot plant in order to validate the proposed scheme

Simplified Interval Observer Scheme: A New Approach for Fault Diagnosis in Instruments

There are different schemes based on observers to detect and isolate faults in dynamic processes. In the case of fault diagnosis in instruments (FDI) there are different diagnosis schemes based on the number of observers: the Simplified Observer Scheme (SOS) only requires one observer, uses all the inputs and only one output, detecting faults in one detector; the Dedicated Observer Scheme (DOS), which again uses all the inputs and just one output, but this time there is a bank of observers capable of locating multiple faults in sensors, and the Generalized Observer Scheme (GOS) which involves a reduced bank of observers, where each observer uses all the inputs and m-1 outputs, and allows the localization of unique faults. This work proposes a new scheme named Simplified Interval Observer SIOS-FDI, which does not requires the measurement of any input and just with just one output allows the detection of unique faults in sensors and because it does not require any input, it simplifies in an important way the diagnosis of faults in processes in which it is difficult to measure all the inputs, as in the case of biologic reactors

DISEÑO Y CONSTRUCCIÓN DE UN EMULADOR DEL CIRCUITO HIDRÁULICO DEL SISTEMA CIRCULATORIO (DESIGN AND CONSTRUCTION OF A HYDRAULIC CIRCUIT EMULATOR OF THE CIRCULATORY SYSTEM)

Resumen Este artículo presenta el diseño e implementación de un emulador de la función hidráulica del sistema cardiovascular. El emulador consiste en 6 tanques interconectados (representando las aurículas, ventrículos, el cuerpo y pulmones), 4 válvulas (representando la mitral, tricúspide, aortica y pulmonar) y 2 bombas para la transportación del líquido (sangre real) del cuerpo hacia el corazón y del corazón hacia los pulmones. Finalmente, se implementa un sistema electrónico basado en un microcontrolador para sintonizar la conducción de las bombas y las válvulas. La principal contribución de este desarrollo es la fabricación de un equipo de demostración y la posibilidad de aplicación multipropósito en diferentes áreas como exposiciones para niños, explicación del funcionamiento del corazón y enfermedades, capacitación de asistentes médicos y estudiantes, capacitación en mecatrónica, practica de ingeniería de control, etc. Palabras Clave: Electrocardiograma, sistema circulatorio, válvulas corazón. Abstract In this paper the design and implementation of an emulator of the hydraulic function of the cardiovascular system is presented. The emulator consists of six interconnected tanks (representing the auricles, ventricles, the body and lungs), four valves (representing the mitral, tricuspid, aortic and pulmonary valves) and two pumps for transportation of the liquid (representing blood) from body towards the heart and from heart towards the lungs. Finally, a microcontroller-based electronic system is implemented to synchronize the driving pumps and the valves. The main contribution of this development is the manufacture of demonstration equipment and the possibility for multi-purpose applications in different areas such as exhibitions for children, explanation of heart functioning and diseases, training of medical assistants and students, mechatronics training, control engineering practice and so on. Keywords: Circulatory system, electrocardiogram, heart valves

Techniques avancées d'observation et de commande non-linéaire pour le génie des procédés

L'application des techniques avancées d'observation et de commande non-linéaire dans le génie des procédés est le thème abordé dans cette thèse. Ces applications sont orientées essentiellement vers deux types de procédés couramment rencontrés dans l'industrie : les biorécateurs et les réacteurs de polymérisation. Une stratégie de commande non-linéaire à modèle interne et une autre à horizon glissant ont été développées. Ces deux stratégies ont comme même objectif la régulation de la concentration de nitrate dans un bioréacteur de dénitrification d'eaux usées. Leurs performances sont testées en simulation en utilisant un modèle mathématique du bioréacteur. Dans le cas des réacteurs de polymérisation, deux cas sont traités. Premièrement, on synthétise un observateur continu-discret pour l'estimation de paramètres variants dans le temps qui n'ont pas le modèle mathématique pour la présentation explicite de leurs dynamiques. Cet observateur a été validé expérimentalement. Deuxièmement, l'utilisation de l'observateur continu-discret avec des algorithmes de commande géométrique pour, d'une part, la poursuite de trajectoire de la température de transition vitreuse dans le cas d'une copolymérisation radicalaire en solution et d'une autre part, la régulation de la composition cumulée du copolymère dans le cas d'une copolymérisation radicalaire en solution.LYON1-BU.Sciences (692662101) / SudocSudocFranceF