Abstract: In this article, an adaptive observer is designed for patients affected by Type 1 Diabetes Mellitus. The adaptive observer, synthesized using the Bergman minimal model, simultaneously estimates the states and the parameter corresponding to the insulin-dependent glucose disappearance rate. The adaptive observer considers parameter uncertainties, whereas food intake is considered an external disturbance. The state estimation error converges to a neighborhood of the origin in the presence of external disturbances and uncertainties, whereas the parameter identification error converges in fixed time to a neighborhood of the origin. The synthesis of the adaptive observer is given by a constructive method based on Linear Matrix Inequalities. Simulation results show the feasibility of the proposed scheme for different classes of patients.

Resumen: En el presente trabajo se describe el problema de diseñar un observador intervalo para un bioreactor de fermentación oscura, con el propósito de: (i) estimar las concentraciones de glucosa y biomasa, y (ii) reducir la influencia de la concentración de glucosa de entrada desconocida y el modelo incertidumbres. Se propone un observador intervalo, reportado en la literatura y constituido por un observador de Luenberger y un predictor intervalar, para una clase de sistemas lineales. El observador intervalo ofrece dos estimaciones: una superior y otra inferior del predictor de intervalo. Las condiciones de diseño, presentadas en este trabajo, se basan en el an´lisis $ mathcal{H}_{infty}$ en combinación con la ubicación de polos en una región estable, las cuales son descritas por desigualdades de matriciales lineales, que no dependen de la propiedad de la Cooperatividad. Finalmente, los resultados en simulación en el modelo linealizado del fermentador oscuro de producción de hidrógeno ilustran la efectividad del método.

Abstract: On the research and development of estimation schemes of beer fermentation processes, in this work the detectability property of two mathematical models of a same process is addressed. The process is a typical one of alcoholic fermentation carried out in a tank bioreactor in batch operation, for which the models include the description of two metabolites related to the beer flavor, in addition to classic variables of yeast, reducing sugars and ethanol. Taking in account that in some practical cases the available on-line measurement is the reducing sugars, and in other ones, the ethanol, three measurement scenarios are considered. The detectability of both models is guaranteed in the scenario in which both reducing sugars and ethanol are measured, and in the case of one of the models, the detectability is even provided when the only measurement is the ethanol. To illustrate the detectability outcomes, an estimator is constructed following a geometric approach, where the tuning of gains is carried out through a pole-placement technique.

Resumen: El diseño de observadores de estado es fundamental para el monitoreo de variables clave de bioprocesos las cuales comúnmente no están disponibles en línea o son costosas de medir. Previo al diseño de observadores se debe analizar la propiedad de observabilidad, la cual permite identificar las variables de salida necesarias para reconstruir los estados de interés. La observabilidad para sistemas no-lineales es un problema complejo que se ha abordado en la literatura. Sin embargo, su aplicación en bioprocesos es escasa. En el presente trabajo se proponen dos metodologías de observabilidad no lineal en un proceso de producción de biohidrógeno: (i) El rango de la matriz de observabilidad con derivadas de Lie, y (ii) el gramiano empírico. Los resultados permiten identificar la medición para fines de diseño de observadores o esquemas de control de salida en el caso de estudio.

Abstract: A well-known strategy for the control of robot manipulators consists in independently controlling each joint. In this paper, we propose a class of time-delay based controllers under this scheme, which ensures practical stability of the tracking position error dynamics corresponding to each joint. In order to tune the controller, a simple methodology based on the feasibility of a Linear Matrix Inequality derived from a proposed Lyapunov-Krasovskii functional is provided. In contrast to classical control algorithms, the presented scheme does not require estimators nor velocity measures but only measures of position at the present and a given delayed time. Numerical simulations show the potential advantages of the proposed class of controllers when position measures are corrupted by noise.

Resumen: En el siguiente artículo se estudia la predicción y el control de un robot móvil diferencial que sufre de un retardo a la entrada de tiempo constante. Se propone dividir el retardo en fracciones mas pequeñas y así utilizar un predictor secuencial basado en un observador tipo Luenberger que estime los valores futuros del sistema de manera gradual. Posteriormente se demuestra la convergencia de los errores de predicción y se utilizan los estados predichos en el control del robot diferencial. Se muestra que los estados pueden ser siempre estimados sin importar el tamaño del retardo a la entrada del vehículo. El costo de esta estrategia se refleja en el aumento de la dimensión del predictor considerado. Finalmente, sin formalizar la estabilidad en lazo cerrado, se presentan resultados numéricos y experimentales para demostrar la eficacia de la predicción.

Abstract: In this work, two cooperative control schemes are developed, one for position and the other for trajectory tracking to move a rigid object using two differential robots. To do this, first, the kinematic model of the differential robots and the cooperative model are obtained. Second, a cascade control algorithm is developed to ensure that the robots reach the reference. To ensure the effectiveness of the trajectory tracking algorithm, the Lyapunov approach is used. To illustrate the proposed system, numerical simulations are performed in MATLAB.

Resumen: En este trabajo se muestra el desarrollo de un esquema de formación para un conjunto de n robots móviles diferenciales en cadena, considerando un tiempo de separación entre cualesquiera par de vehículos consecutivos. Se propone un esquema semi-descentralizado, utilizando únicamente mediciones relativas entre robots y datos proporcionados por los encoders y giroscopio de los vehículos seguidores, sin la consideración de un sistema de posicionamiento global para la formación completa. Se realiza un análisis de la estabilidad de la formación mediante técnicas de Lyapunov. Finalmente se muestran algunos resultados en simulación numérica y experimentales que permiten validar el funcionamiento del esquema propuesto.

Resumen: En este trabajo se realiza un análisis comparativo entre algoritmos de identificación en línea y fuera de línea en la estimación de parámetros de un modelo que describe a un servomecanismo de CD de cuatro parámetros. Los algoritmos bajo estudio son los métodos gradiente, mínimos cuadrados y mínimos cuadrados modificado. Estos se prueban en un prototipo de laboratorio con el fin de estimar dicho modelo. La idoneidad de los parámetros estimados se evalúa mediante su empleo en una ley de control que tiene como fin el seguimiento de una trayectoria variante en el tiempo.

Resumen: La estimación de parámetros para los modelos biomecánicos existentes en la literatura es esencial para que estos últimos sean de utilidad en aplicaciones de ingeniería, tanto para predecir el comportamiento de los órganos como para poderlos representar lo más fielmente posible en entornos de realidad virtual o simuladores hápticos. En este trabajo se presenta un esquema de estimación de parámetros del modelo de Kelvin modificado, disponible en la literatura. Uno de los objetivos es obtener señales de excitación que sean lo menos invasivas posibles en un escenario de obtención de señales in vivo, por lo que se exploran estrategias para reducir el número de experimentos y la riqueza de las señales necesarias para estimar los parámetros biomecánicos del modelo. Se presentan resultados de simulación y experimentos para validar el enfoque propuesto.

Abstract: In this paper we present an alcoholic fermentation model from a single substrate to a product, via a microorganism in a continuous reactor subject to an influx containing substrate, biomass, and product. We take into account the reproduction of the microorganism while consuming substrate; as a product of its metabolism we consider ethanol production. Furthermore, we include in the model the microorganism's death or its definitive inactivation. Our framework assumes constant environmental conditions, such as temperature, pH, and concentrations of the mineral medium. To finalise, we avail of nonlinear optimisation tools to fit the parameters of our model, such that its time-solution resembles the one available in the literature.

Resumen: Este estudio establece un método para detectar y distinguir entre cuatro niveles de daño que causa la cenicilla polvorienta en hojas de calabacita. El problema principal es la generación de datos con firmas espectrales obtenidos de plantas sanas y enfermas. Para resolver esto, las firmas espectrales originales de las hojas, son utilizadas como un patrón espectral para la detección. Los niveles se describieron con las longitudes de onda caracterizadas en regiones y agrupadas en niveles de daño. Como resultado, se obtiene que a través de cálculos estadísticos, como el análisis de varianza y la prueba de Tukey, diferencias significativas entre los niveles de daño son notables al considerar las longitudes de onda de las bandas del verde al rojo y cercano al infrarrojo de 450 nm - 550 nm, 550 nm - 650 nm y del 650 nm - 750 nm. Estos resultados ofrecen datos caracterizados para usarse a futuro en clasificación de enfermedades en plantas y para la detección temprana de enfermedades fúngicas.

Abstract: This research deals with the optimal control of make-up lubricating systems for internal combustion engines. Firstly, classic mass balances are proposed to depict the dynamics of the width of the tribological film protecting the rubbing surfaces; this is a competitive “renovation-removal” process that can reach optimal steady state. Secondly, to regulate the film width in this steady state, optimal trajectories of make-up of lubricant in the engine's oil pan and supply of lubricant from the oil pan to the engine are deduced using optimal control methodology. Results show feasible tracks to be followed by lubricating system to reach the optimal steady state, which simultaneously minimize the lubricant consumption.

Abstract: In this contribution, a thermodynamics based regulation problem is proposed to control a counter flow shell-and-tube heat exchanger. To regulate the system, an output error, correlated with the total entropy production inside the heat exchanger, is proposed; this error depends on the output variable, its reference, the control variable and the measured disturbances, therefore a dynamical controller with a PID behavior is derived as a preliminary solution of the proposed regulation problem. Finally, this controller is tested via numerical simulation showing satisfactory stability properties.

Abstract: A methodology to select a self-optimizing control structure for a dividing wall column (DWC) is evaluated, the proposed methodology uses reflux flow rate and reboiler heat input as manipulated variables to control temperature of different stages of the column. The selection of the multivariable control structure is based on the minimization of a cost function dependent on the amount of impurity in each product stream of the column. The design sequence of each control loop also reduces the interaction between the control loops.

Abstract: Solar collectors are heat exchangers that transfer solar energy to a fluid in the form of heat; however, the problem is that solar energy is not constant, and it is essential for industrial applications the deliver a continuous thermal load or constant temperature. In this paper, we avail of a nonlinear mathematical model developed by us. Such a model predicts the collector's output temperature subject to time-varying, unknown solar irradiance, ambient temperature, and wind speed. To deliver a constant temperature at the collector outlet, we designed a PI control, considering the derivative of the input flow (dṁ/dt) to the collector as a manipulated variable. We show its applicability through simulation but considering natural environmental conditions.

Abstract: In this paper the joint optimal operation and Lyapunov-based tracking control design for binary batch distillation columns with temperature measurements is addressed. The combination of standard batch distillation dynamics concepts with nonlinear constructive control theory allows to design a temperature-measurement driven control policy that enforces the distillate composition to reach its prescribed value in finite time, including two sequential operation mode. First, the system is operated at total reflux (i.e., with no production) for a period of time, to set a proper temperature (i.e., composition) profile in the column. Then, the production period is performed with a suitable temperature-to-temperature Lyapunov tracking controller that enforces the prescribed constant distillate purity policy, without significant overpurification. The methodology includes: (a) guides to select the proper sensor locations, (b) a temperature measurement-driven criteria to set the switching time from total reflux to production period, (c) the on-line generation of temperature policies that ensure constant distillate purity, and (d) a temperature-to-temperature Lyapunov tracking controller that enforces the prescribed constant distillate product purity policy. The methodology is tested with representative binary systems.

Abstract: This article presents the design, construction and start-up of an experimental platform for the evaluation of schemes for pedaling assistance of electric bicycles. The experimental platform represents a front-wheel drive bicycle. The motor used is a direct current motor (DC motor). The acquisition of the measured signals (angular position and current of the DC motor) and the generation of the PWM signals is carried out in the ARDUINO MEGA 2560. The signals monitoring and control programming was done in MATLAB/Simulink. At this stage, a PI controller is used to regulate the DC motor speed to verify the correct platform operation.

Abstract: This work proposes a control strategy for revoluta joints manipulators using an equivalent manipulator composed of a revoluta joint and a prismatic joint. The equivalent model allows a better characterization of the interaction between a manipulator and a mobile base, for example in an aerial manipulator. The equivalence conditions presented, allows to design the control strategy under the equivalent model representation and implement it on the real model. Through numerical simulations, the effectiveness of the proposed control system is evaluated.

Abstract: This article presents a concise review of interaction laws between electrostatic charges applied to path planning for a mobile robot. %% The robot is represented as a punctual charge, moving freely in a predefined workspace or chart. %% The proposed methodology must help to estimate the free trajectory to reach a pre-established goal. %% The electrostatic interactions between the multiple elements of the environment (obstacles) and robot allow to dynamically determine a smooth trajectory, using minimum energy. %% Besides, the study includes the performance evaluation of different robust optimization techniques to solve the electrostatic charges interaction problem, estimating a fast and stable trajectory. %% The robot navigation is simulated, including the position or speed control parameters to improve displacement with a smoothed trajectory. % In this way, the robot can evolve in complex environments as long as it disposes of the appropriate sensory information, even in dynamic environments.

Abstract: The aim of this paper is to design a robust controller for the perturbed kinematic model of the Unicycle Mobile Robot. The proposed controller is based on the Super-Twisting algorithm and, given the underactuated nature of the system, two sliding surfaces are proposed to ensure asymptotic convergence of the tracking error to zero, despite the presence of some external disturbances. The synthesis of the proposed controller is given in terms of Linear Matrix Inequalities while the convergence proofs are based on the Lyapunov and Input-to-State Stability theory. Simulation results show the feasibility of the proposed approach.

Abstract: In this paper, the problem of model equivalence between integer-order and fractional-order systems with Caputo derivative is considered. Motivated by diverse studies that show a connection between the diffusion model and its equivalent fractional diffusion models, the construction of the integral transformation is presented that maps the solution of the one-dimensional integer diffusion model to the equivalent solution of the fractional diffusion model. It is demonstrated that the unique integral transformation between both models corresponds to the {integral} of half-order. The derivation includes the inverse integral transformation, which allows the validation of the equivalence and well-posedness of the models. Moreover, the explicit analytic solution for the equivalent fractional partial differential equation is given through the proposed transformation.

Abstract: A methodology is developed to obtain Bond Graph models from the position vectors of centers of mass and rotation matrices in mechanical systems. In this methodology, the equations of tangential velocity, the rotation matrix and the inertia associated with the centers of mass and potential energy of the physical system are used. This method is applied to the mechanical part of a small fixed blade wind turbine and a Rotational-Rotational (RR) robot. The objectives are to model the yaw dynamics and the rotational speed of the rotor in the wind turbine and the rotational angles of the RR robot. The implementation and comparison of the results is carried out, both in 20-sim and in Matlab-Simulink from the Lagrange equations and Simscape Toolbox, these results are compared to verify the proposed models. For the yaw angle model, the wind turbine steering vane is removed and a mechanism is proposed that allows the wind turbine to move to the desired angle, around the vertical axis.

Abstract: In this paper, the Autoregressive Moving Average (ARMA) model is used for the time series prediction with chaotic dynamic. The estimation of the weights vector of ARMA model can be obtained through an adaptive algorithm based on stochastic gradient descent, such that the prediction performance of a chaotic time series performed through ARMA model is influenced by the value of the step size. For this, in this paper, a new version of Normalized Least Mean Square (NLMS) algorithm is proposed with the step size adapted by a Mamdani Fuzzy Inference System (MFIS) used for estimation of the weights vector of ARMA model, for the time series prediction with chaotic dynamic.

Abstract: This paper aims to propose a new hybridization involving the Genetic Algorithm (GA) and the Particle Optimization Swarm (PSO). The objective of the proposed optimization algorithm is to perform the search process for optimal solutions in complex problems with a fast and non-premature convergence. Since the satisfactory convergence of the search process is a result of a good trade-off between global and local search, in order to achieve the objective of the proposed optimization algorithm, a Mamdani Fuzzy Inference System (MFIS) is used for fuzzy parametric adaptation of the acceleration coefficients and inertial weight of PSO. Through this parametric adaptation, which is performed using a linguistic description based on the expert's knowledge and implemented in a fuzzy rule base, it is possible to obtain a good trade-off between global and local search in complex optimization problems.

Abstract: In this paper, a robust nonlinear model reference adaptive controller is proposed to solve the problem of blood glucose regulation for critically ill patients affected by type 1 diabetes mellitus. The proposed method considers blood glucose measurement and insulin infusion via intravenous. The proposed scheme copes with external disturbances such as food intake, unmodeled dynamics, and parameter uncertainties given by the interpatient variability. The algorithm can regulate asymptotically the blood glucose to the basal glucose level. The approach is validated in the UVA/Padova metabolic simulator for 10 in silico adult patients without meal advertisement. Minimal risks of hyperglycemia and hypoglycemia are achieved.

Abstract: The monitoring of key variables in physical, chemical, and biological processes represents important information for analyzing and/or evaluating performance and stability of processes. However, it is not always possible to obtain key variables measurements (e. g. reagent and product concentrations) on real time, therefore, indirect monitoring, using easily measured variables, is a useful alternative. In this paper a study of wavelet transform application for pH time series analysis as an alternative for indirect monitoring of anaerobic digestion is presented. Two case studies, tequila vinasse and cheese whey, were analyzed, determining that wavelet transform can be used as a tool for qualitative monitoring of the anaerobic digestion process operated at different operating conditions.

Abstract: In this work, the problem of robustly controlling and monitoring the functioning of an Hydrothermal Carbonization (HTC) batch reactor is addressed. First, the nominal optimal operation is designed by means of dynamical inversion. Then, the application of constructive control with passivity, optimality and detectability notions yields a nonlinear (NL) robust estimator-based output-feedback (OF) tracking optimal controller. From an industrial perspective, the proposed NL OF controller is a control-monitoring (CM) system that tracks the nominal temperature, decides the batch duration, and provides estimates of the physical states and the economic one. The problem is solved within a constructive framework, yielding a CM system design methodology with: (i) systematic construction, (ii) robust functioning, and (iii) a simple tuning scheme. The proposed design is illustrated and tested with a representative example through numerical simulation.

Resumen: Este trabajo presenta un análisis comparativo de tres observadores de estado no lineales aplicados al proceso sulfato reductor por Desulfovibrio alaskensis 6SR en presencia y ausencia de Cr(VI). Los observadores consisten en su estructura de una retroalimentación simple proporcional (Obs.-1), proporcional- integral (Obs.-2) y proporcional-integral-exponencial (Obs.-propuesto), que se evalúan a diferentes condiciones iniciales. Los observadores se utilizan para estimar la concentración de sulfato y la concentración de sulfuro de hidrógeno a partir de la concentración de biomasa en el biorreactor. El desempeño de los observadores se evalúa en términos del indicador del error ITSE.

Resumen: En este artículo se presenta la implementación del gemelo digital de un proceso secuencial electroneumático, para el cual se desarrolló el modelo tridimensional del proceso mediante la utilización de herramientas de diseño asistido por computadora con base en la información proporcionada por las hojas del fabricante e ingeniería inversa. Para describir la dinámica del sistema se propone un modelo matemático mediante ecuaciones diferenciales no lineales, este modelo es implementado en EmulPro que nos permite emular el proceso y mediante una conexión OPC, se conecta con su contraparte física. Se realizó una evaluación al gemelo digital en dos escenarios. En el primer escenario se evaluó la respuesta del sistema a la expulsión y retracción del émbolo. En el segundo escenario se evaluó en tiempo real el control de tres cilindros de doble efecto mediante una secuencia implementada con la metodología GRAFCET, programada en el lenguaje SFC bajo la norma IEC 61131-3, utilizando el controlador ControlLogix y el software Studio 5000 Logix Designer. Los resultados mostraron que el gemelo digital desarrollado puede ser utilizado para la evaluación rutinas de control secuencial.

Resumen: Investigadores de diversas disciplinas han abordado el problema del control de la energía de las olas desde la década de 1970. Sin embargo, queda mucho trabajo por desarrollar en el diseño de estrategias de control que funcionen bien en todo el espacio operativo del WEC, que sean insensibles a los errores de modelado y perturbaciones. En este artículo se presenta la aplicación de un controlador adaptable basado en Lyapunov con el propósito de resolver el problema de máxima extracción para un WEC del tipo punto absorbente visto como un proceso particular de un convertidor de energía de las olas en el que se desconoce la parte hidrodinámica del sistema. La evaluación del sistema de control se realiza mediante una simulación numérica considerando un modelo no lineal para el flotador con fuerza de difracción irregular.

Abstract: This work compares three methods for efficiency improvement of a point absorber wave energy converter (WEC) with approximated optimal control by adjusting the mechanical impedance of the floater dynamics. The case study is a WEC based on an Archimedes wave swing prototype. The well-established phase and amplitude conditions for floaters in the frequency domain are considered as guidelines for the efficiency improvement objective for a floater with nonlinear damping. The phase condition is considered to be fulfilled by matching the natural frequency of oscillation with the dominant frequency of the incident waves. This is a feature of the mechanical structure of the WEC under study. Thus, the three methods considered aim to satisfy the amplitude condition for the WEC under study. These methods seek to correct the total damping by shaping the force produced by the electrical generator. The first method considers a linear approximation of the nonlinear damping produced by the brakes in the WEC structure. The second method imposes a linear dynamic by compensating the nonlinear damping. Finally, the third method is proposed following a variation for nonlinear resistive networks of the maximum power transfer theorem. From numerical simulations with both regular and irregular sea waves, including a sensitivity analysis of the corrected damping, the third option shows a better performance regarding energy conversion followed by the first option.