A design procedure for a supervisory control structure in plantwide control

Abstract: This work presents a methodology for designing a supervisory control structure in Plant-wide Control (PWC). First, available PWC structures are discussed focusing on their drawbacks originated from the scarce flexibility and simplicity when implementing them in industrial environments. Additionally, the available control strategies involve decoupling of the process, losing all interactions information and therefore requiring more complex models inside the control structure to account for interactions among units. To overcome this, a hierarchical approach to PWC is proposed, introducing a two–layer control structure where dynamics on the regulatory layer are classified by hierarchical association considering that process dynamics and their set–points are optimized on the supervisory layer to achieve collaboration among Proportional–Integral–Derivative (PID) controllers in the regulatory layer. A dynamics hierarchy is established by means of the process Hankel matrix that quantifies the effect of all input variables over each state variable of the plant. Finally, the proposed methodology is applied to a Reactor–Separator–Recycle system for propylene glycol production, where a better process performance is reached using the hierarchical approach in comparison with the decentralized proposal.Resumen: Este trabajo presenta una metodología de diseño para estructuras de control supervisorio en control total de planta (CTP). Primero se discuten las estructuras de CTP resaltando sus limitaciones, como baja flexibilidad y simplicidad para su implementación industrial. Adicionalmente, estas estructuras involucran el desacople de las dinámicas del proceso, perdiendo la información sobre las interacciones del mismo y por ende, requiriendo modelos más complejos dentro de la estructura para dar cuenta de estas interacciones. Para superar estas limitaciones, se propone una estructura de control jerárquica, introduciendo una estructura de control con dos niveles, en la que las dinámicas en el nivel regulatorio son clasificadas jerárquicamente considerando el comportamiento dinámico del proceso y sus puntos de ajuste son optimizados en el nivel supervisorio alcanzando un esquema colaborativo entre los controladores Proporcional–Integral–Derivativo (PID) del nivel regulatorio. La jerarquía de dinámicas en el nivel regulatorio se establece por medio de la matriz de Hankel del proceso, que cuantifica el efecto de toda las variables de entrada sobre cada estado del proceso. Finalmente, la metodología propuesta se aplica para controlar un sistema Reactor– Separador–Reciclo para producción de propilenglicol, logrando unmejor desempeño usando la estructura jerárquica comparado con una estructura decentralizada.Maestrí

Control-Oriented Model with Intra-Patient Variations for an Artificial Pancreas

In this work, a low-order model designed for glucose regulation in Type 1 Diabetes Mellitus (T1DM) is obtained from the UVA/Padova metabolic simulator. It captures not only the nonlinear behavior of the glucose-insulin system, but also intrapatient variations related to daily insulin sensitivity (SI) changes. To overcome the large inter-subject variability, the model can also be personalized based on a priori patient information. The structure is amenable for linear parameter varying (LPV) controller design, and represents the dynamics from the subcutaneous insulin input to the subcutaneous glucose output. The efficacy of this model is evaluated in comparison with a previous control-oriented model which in turn is an improvement of previous models. Both models are compared in terms of their open- and closed-loop differences with respect to the UVA/Padova model. The proposed model outperforms previous T1DM controloriented models, which could potentially lead to more robust and reliable controllers for glycemia regulation.Fil: Moscoso Vásquez, Hilda Marcela. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Instituto Tecnológico de Buenos Aires. Departamento de Matemática. Centro de Sistemas y Control; ArgentinaFil: Colmegna, Patricio Hernán. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. University of Virginia; Estados Unidos. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología; ArgentinaFil: Rosales, Nicolás. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones en Electrónica, Control y Procesamiento de Señales. Universidad Nacional de La Plata. Instituto de Investigaciones en Electrónica, Control y Procesamiento de Señales; ArgentinaFil: Garelli, Fabricio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones en Electrónica, Control y Procesamiento de Señales. Universidad Nacional de La Plata. Instituto de Investigaciones en Electrónica, Control y Procesamiento de Señales; ArgentinaFil: Sanchez Peña, Ricardo Salvador. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Instituto Tecnológico de Buenos Aires. Departamento de Matemática. Centro de Sistemas y Control; Argentin

Two-dimensional posture evaluation in Parkinson’s disease: effect of loads on the spinal angle during gait

Parkinson’s Disease patients present diminished coordination caused by neural degeneration. This leads to large motor difficulties during gait such as balance loss and pronounced forward inclination of the upper body. This work assessed the spinal sagittal plane angle alterations in two groups: six parkinsonian patients and six control healthy subjects. This parameter was analyzed during gait under three conditions: without external loads and with external loads applied either on the chest or on the lower back area. Results were statistically compared by means of t-test of paired samples in both groups. For patients, a significant effect was found when loads were applied on the chest. On the other hand, healthy subjects showed no significant differences in either case.Fil: Celoria, Paula. Instituto Tecnológico de Buenos Aires; ArgentinaFil: Nanni, Federico. Instituto Tecnológico de Buenos Aires; ArgentinaFil: Pastore, Flavia. Instituto Tecnológico de Buenos Aires; ArgentinaFil: Pulenta, Sebastian. Instituto Tecnológico de Buenos Aires; ArgentinaFil: Tajerian, Matias. Instituto Tecnológico de Buenos Aires; ArgentinaFil: Pantazis, Lucio José. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Instituto Tecnológico de Buenos Aires; ArgentinaFil: Moscoso Vásquez, Hilda Marcela. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Instituto Tecnológico de Buenos Aires; ArgentinaFil: Cerquetti, Daniel. Fundación para la Lucha contra las Enfermedades Neurológicas de la Infancia; ArgentinaFil: Merello, Marcelo Jorge. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Fundación para la Lucha contra las Enfermedades Neurológicas de la Infancia; ArgentinaFil: Risk, Marcelo. Instituto Tecnológico de Buenos Aires; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

Modelos Orientados para Control Incluyendo Variaciones Intrapaciente para Sistemas de Pancreas Artificial

En los últimos años se ha incrementado el número de investigaciones orientadas al desarrollo de un Páncreas Artificial (AP) para la regulación automática de glucosa en pacientes con Diabetes Mellitus Tipo 1 (T1DM). Sin embargo, el riesgo de hiper- e hipoglucemia sigue siendo un impedimento para una regulación adecuada de la glucemia en algunos casos. Una fuente importante de limitaciones se origina a partir de la incertidumbre del modelo, y la alta variabilidad inter- e intra-paciente que afecta la dinámica de la regulación de la glucosa. Por lo tanto, considerando que se requieren herramientas para el diseño de estrategias de control robustas y variables en el tiempo que permitan considerar estos aspectos, esta tesis se centra en desarrollar modelos que permitan integrarlos en la etapa de diseño del controlador. Con el fin de caracterizar las variaciones intra-paciente en sujetos con T1DM, se realiza una revisión de su origen y la fisiología subyacente relacionada con esta variabilidad, obteniendo un resumen de las variables que afectan los requerimientos diarios de insulina de cada paciente. Además, se analizan los enfoques para modelado/simulación de las variaciones de sensibilidad a la insulina (SI) y las diferentes maneras en las que se han tenido en cuenta estas variaciones en los modelos orientados a control. En el marco del control robusto, se obtienen diferentes modelos orientados al control de T1DM incluyendo las variaciones en SI . Primero, a partir de un modelo lineal de parámetros variantes (LPV) desarrollado previamente, usando técnicas de invalidación, un conjunto de modelos de bajo orden capaz de“cubrir”las variaciones intra-pacientes con límites de incertidumbre dinámica. Este conjunto de modelos es fundamental para el diseño de controladores robustos que garanticen estabilidad y desempeño. En segundo lugar, se incluyen variaciones intra-pacientes durante la etapa de identificación del modelo, lo que permite integrarlas dentro de una estructura LPV de bajo orden adecuada para el diseño de controladores LPV. La eficacia de este nuevo modelo se evalúa de la siguiente forma. Por un lado, se computa el error cuadrático medio (RMSE) entre las desviaciones de glucosa predichas por los modelos LPV con y sin variaciones intra-paciente y el simulador. Por otro lado, se miden las distancias entre ambos modelos y el simulador a través del -gap, a fin de determinar las diferencias de desempeño a lazo cerrado. Finalmente, se desarrolla un modelo LPV que permite dar cuenta de los efectos de la hiperglucemia/hiperinsulinemia en la sensibilidad a la insulina y su efectividad se evalúa nuevamente en lazo abierto y lazo cerrado.Research on the development of a closed-loop artificial pancreas for automatically regulating theblood glucose level in Type 1 Diabetes Mellitus (T1DM) patients has intensified in the past years.However, the risk of hyper- and hypoglycemia remains an impediment to adequate glycemic control in some cases. A significant source of limitations originates from model uncertainty, and the extremely high inter- and intra-patient variability that affects the dynamics of glucose regulation. Therefore, considering that tools are required for the design of robust and time-varying control strategies that consider these issues, this thesis focuses on developing control-oriented models that allow considering them in the controller design stage.In order to characterize intra-patient variations in T1DM, a review of the sources and underlying physiology related to intra- and inter-day variability is made, obtaining a summary of the variables affecting daily insulin requirements. Moreover, modeling/simulation approaches of Insulin Sensitivity (SI) variations that have been adapted for T1DM are analyzed. Additionally, the different ways they have been accounted for in control-oriented models are reviewed.Following a robust control framework, different control-oriented models including variations in SI are obtained. First, invalidation techniques are applied to a previous linear parameter varying (LPV) model to develop a set of low-order LPV models that\covers"intra-patient variations with dynamic uncertainty bounds. This model set is instrumental for obtaining robust controllers that guarantee stability and performance. Secondly, intra-patient variations are included during the model identification stage to embed them within a low-order LPV model structure that is amenablefor LPV controller design. The performance of this new model was evaluated in comparison with the previous LPV model without intra-patient variations in terms of their open- and closed-loop differences with the UVA/Padova model. In open-loop, the analysis is made through the Root Mean Squared Error (RMSE) between the glucose deviation predicted by the models and the UVA/Padova simulator. In closed-loop, the nu-gap metric was used, which measures the distance,in terms of performance, between two models. Finally, an LPV model that allows to account for the effects of hyperglycemia/hyperinsulinemia on insulin sensitivity is developed and evaluated both in open- and closed loop.Fil: Moscoso Vásquez, Hilda Marcela. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Instituto Tecnológico de Buenos Aires; Argentin

Model-based supervisory control structure for plantwide control of a reactor-separator-recycle plant

This work presents a methodology for designing a supervisory control structure in plantwide control (PWC). First, available PWC structures are discussed focusing on their drawbacks originating from the scarce flexibility and simplicity when implementing them in industrial environments. To overcome this, a hierarchical approach to PWC is proposed that introduces a two-layer control structure, where the regulatory layer dynamics are classified by hierarchical association and their set points are optimized on the supervisory layer to achieve collaboration among proportional-integral-derivative (PID) controllers. Here, the dynamics hierarchy is established by means of the process Hankel matrix that quantifies the effect of all input variables over each state variable of the plant. Finally, the proposed methodology is applied to a reactor-separator-recycle system for propylene glycol production, where a better process performance is reached using the hierarchical approach in comparison with a decentralized control structure.Fil: Moscoso Vásquez, Hilda Marcela. Universidad Nacional de Colombia; Colombia. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Monsalve Bravo, Gloria Milena. Universidad Nacional de Colombia; ColombiaFil: Alvarez, Hernan. Universidad Nacional de Colombia; Colombi

Scale-up of continuous reactors using phenomenological-based models

A methodology for scaling up continuous reactors using a Phenomenological-Based Semiphysical Model (PBSM) of the process is presented. First, a review of the most popular scale-up methods is made, finding that these methods do not guarantee an adequate commercial unit design and that a PBSM is a fundamental tool when scaling up chemical reactors. Taking into account these facts, a novel methodology is presented in which a process PBSM and its Hankel matrix are used for analysing the process dynamic behaviour and scaling it up, including the effect of the design variables over each state variable. Finally, the proposed methodology is applied to a polymerization reactor, comparing the scaled unit design when using this approximation and a traditional method, finding the scale factors for keeping the same polymer molecular weight at the new scale and, demonstrating that traditional scale-up methods do not always lead into the best commercial unit design.Although the scale-up activity is one of the major tasks for chemical engineers and represents a fundamental step in the design and optimization of industrial plants (1), since the 1960s there has not been significant progress in the methods for scaling up chemical reactors (use of rules of thumb, similarity criteria and dimensional analysis) (2-7). Industrial scale-up is dominated by empirical criteria that require geometrical similarity fulfilment, leading to drawbacks from keeping a single parameter constant (8, 9) and originating changes in other important variables. This fact results in an erroneous commercial unit design that demands additional costs and time to be corrected (10-12).Fil: Monsalve Bravo, Gloria Milena. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Colombia; ColombiaFil: Moscoso Vásquez, Hilda Marcela. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Colombia; ColombiaFil: Alvarez, Hernan. Universidad Nacional de Colombia; Colombi

Scaleup of Batch Reactors Using Phenomenological-Based Models

This work presents a methodology for scaling up Batch Processes (BPs). First, a review of the most popular scale-up methods differentiating batch from continuous processing is made, finding that traditional scale-up approaches do not consider BPs characteristics and that many particular successful cases are reported, but no formal procedure has been developed for scaling up these processes. Considering these facts, a novel scale-up procedure is presented, in which a process Phenomenological-Based Semiphysical Model PBSM and its Hankel matrix are used for computing the State Impactability Index (SII) that allows to determine: (i) the process main dynamics at each stage of the batch and (ii) the critical point of the Operating Trajectory (OT) at which the batch must be scaled-up. Finally, the methodology is applied to a batch suspension polymerization reactor, comparing the scaled unit design when using this approximation and a traditional method.Fil: Monsalve Bravo, Gloria Milena. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Colombia; ColombiaFil: Moscoso Vásquez, Hilda Marcela. Universidad Nacional de Colombia; Colombia. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Alvarez Zapata, Hernán. Universidad Nacional de Colombia; Colombi

Non-pharmaceutical intervention to reduce COVID-19 impact in Argentina

This work is focused on the multilevel control of the population confinement in the city of Buenos Aires and its surroundings due to the pandemic generated by the COVID-19 outbreak. The model used here is known as SEIRD and two objectives are sought: a time-varying identification of the infection rate and the inclusion of a controller. A control differential equation has been added to regulate the transitions between confinement and normal life, according to five different levels. The plasma treatment from recovered patients has also been considered in the control algorithm. Using the proposed strategy the ICU occupancy is reduced, and as a consequence, the number of deaths is also decreased.Fil: García Violini, Diego Demián. Universidad Nacional de Quilmes; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Sanchez Peña, Ricardo Salvador. Instituto Tecnológico de Buenos Aires; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Moscoso Vásquez, Hilda Marcela. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Instituto Tecnológico de Buenos Aires; ArgentinaFil: Garelli, Fabricio. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de La Plata; Argentin

Invalidation and low-order model set for artificial pancreas robust control design

The purpose of this work is to compute a linear parameter-varying (LPV) model set that describes the insulin-glucose dynamics in type 1 diabetes (T1D). This set includes a nominal LPV model and dynamic uncertainty and is amenable to controller design. The nominal model is an LPV control-oriented model previously published by the authors that is (in)validated in this work against the UVA/Padova metabolic simulator. The result is a set of models that is used to design a switched LPV robust controller to account for nonlinearities and variations in insulin sensitivity (SI). Closed-loop responses obtained with the robust controller and a nominal one are compared. Results illustrate the convenience of including robust strategies in designing control laws for an artificial pancreas (AP).Fil: Bianchi, Fernando Daniel. Comisión Nacional de Energía Atómica. Gerencia del Área de Energía Nuclear. Instituto Balseiro; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte; ArgentinaFil: Moscoso Vásquez, Hilda Marcela. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Instituto Tecnológico de Buenos Aires; ArgentinaFil: Colmegna, Patricio Hernán. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Quilmes; Argentina. University of Virginia; Estados UnidosFil: Sanchez Peña, Ricardo Salvador. Instituto Tecnológico de Buenos Aires; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

Artificial pancreas: the Argentine experience

The objective of this work is to present a brief review on the international Artificial Pancreas project. In addition, the local project that led to the first Latin American clinical trials with an Artificial Pancreas will be described. These trials were performed in Buenos Aires during 2016 and 2017. The last trial used an algorithm developed in Argentina and defined as the ARG (Automatic Regulation of Glucose). This procedure and its in silico and clinical results will also be presented in this paper.Fil: Colmegna, Patricio Hernán. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. University of Virginia; Estados UnidosFil: Garelli, Fabricio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones en Electrónica, Control y Procesamiento de Señales. Universidad Nacional de La Plata. Instituto de Investigaciones en Electrónica, Control y Procesamiento de Señales; ArgentinaFil: Fushimi, Emilia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones en Electrónica, Control y Procesamiento de Señales. Universidad Nacional de La Plata. Instituto de Investigaciones en Electrónica, Control y Procesamiento de Señales; ArgentinaFil: Moscoso Vásquez, Hilda Marcela. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Instituto Tecnológico de Buenos Aires; ArgentinaFil: Rosales, Nicolás. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones en Electrónica, Control y Procesamiento de Señales. Universidad Nacional de La Plata. Instituto de Investigaciones en Electrónica, Control y Procesamiento de Señales; ArgentinaFil: García Violini, Diego Demián. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Instituto Tecnológico de Buenos Aires; ArgentinaFil: de Battista, Hernán. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones en Electrónica, Control y Procesamiento de Señales. Universidad Nacional de La Plata. Instituto de Investigaciones en Electrónica, Control y Procesamiento de Señales; ArgentinaFil: Sanchez Peña, Ricardo Salvador. Instituto Tecnológico de Buenos Aires; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin