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There are different devices capable of discriminating optical and optoelectronic noise, however, the cost of its implementation and maintenance is expensive. This paper examines the possibility of digitally integrating Finite Impulse Response (FIR) filters into the transducer of an OSS systems to obtain better performance in a real operating environment. In this paper we propose the evaluation of the implementation of different FIR filters in different photo-sensors transducers, such as the Light-Dependent Resistor (LDR) and the Light Emitting Diode (LED).

This paper presents the design and application of passivity–based control theory for distributed energy resources (DERs) integration through voltage source converters (VSC) in ac single–phase grids. The Hamiltonian representation of these grids facilitates the development of passive controllers that guarantee stability in the sense of Lyapunov for their closed–loop operation. The non–autonomous dynamic modeling of these systems is transformed into an incremental model, which allows solving the tracking as a regulation problem. The main contribution of this paper is in the ability to control the active and reactive power transference between DERs and the ac single–phase grid depending on the availability of the primary energy resource and the capacity of the converters. Simulations results show that all proposed controllers attain the control objective, reaching the same dynamic performance as classical proportional–integral controllers and guaranteeing asymptotic stability. All simulations are developed under the MATLAB/Simulink environment through the SimPowerSystems tool.

In a previous paper the authors compared the AC-AC converters, useful for the frequency regulation in hydroelectric microplants varying the power dissipated in ballasts loads, with the new proposal consisting in a bridge three-phase rectifier using diodes with a serial switch with the load that is switched with symmetric angle. The paper showed that the aforementioned rectifier accomplishes to improve the power factor at the generator output, except for low power consumed by users, near to its minimal value. A way to solve this problem consists in to use three bridge single-phase rectifier using diodes with a serial switch with the load that is switched with symmetric angle. As a consequence, the objective of this article is to carry out a comparison between the aforementioned single-phase rectifier and the AC-AC converter, regarding the power factor at the output of the electric generator of hydroelectric micro-plants that regulate frequency by means of the ballast-load method.

This paper presents a family of mechanisms of two degrees of freedom for implementing variable geometry hybrid wheels. These mechanisms are capable of transforming a circular wheel into a hybrid wheel with multiple legs. In this paper we describe the main attributes and advantages of these mechanisms, which we named HeIse Wheels. In addition, various terms and concepts related to the mathematical modeling of these devices are defined. The family of mechanisms consists of 14 original designs, which represent a sound solution to the problem of wheel-hybrid wheel transformation.

This paper proposes the design and development of a telescope network scheduler for the GLORIA telescope network. This telescope network, which main objective is helping users to get involved in astronomy research, is composed by 18 heterogeneous telescopes located in different countries. These telescopes are managed by the scheduler to execute the observations requested by the users. A key module of this scheduler is the telescope decision algorithm which objective is to avoid serving an observation to a telescope that cannot execute it. This paper proposes two different algorithms: the first one is based on weather forecast, and the other one is based on fuzzy logic. Both algorithms were deployed and used into the GLORIA network, an analysis of the results and a performance comparative between both algorithm are shown in this paper. As well, the scheduler architecture based on a hybrid distributed-centralised schema is detailed.

Resumen: En este trabajo se presenta una familia grande de reguladores saturados tipo hiperbólicos para robots manipuladores. La propuesta considera a la ganancia proporcional constante y a la ganancia derivativa variable con sintonía automática definida en función del error de posición, velocidad de movimiento y un factor de inyección de amortiguamiento para modificar la velocidad de respuesta del robot. La acción de control derivativa con ganancia variable permite reducir sobreimpulsos, oscilaciones y rizo, tal que alcance el estado estacionario en forma suave. Asimismo, se presenta la propuesta de una función estricta de Lyapunov que permite demostrar la estabilidad asintótica global de la ecuación en lazo cerrado. Para mostrar el desempeño y funcionalidad de la familia propuesta de esquemas de control, un análisis comparativo experimental fue desarrollado entre siete estructuras de control, cinco reguladores pertenecen a la familia propuesta, y dos algoritmos de control bien conocidos como son el proporcional derivativo (PD) y tangente hiperbólico (Tanh). Los resultados experimentales fueron obtenidos con un robot manipulador de transmisión directa de tres grados de libertad. Abstract: In this paper a family with a large number of hyperbolictype saturated regulators for robot manipulators, was presented. The proposed regulators consider a constant proportional gain while the derivative variable gain is self-tuned according to a function that depends on the position error, speed of motion and a damping factor, in order to modify the velocity of the transient response of the robot. The derivative control with variable gain enables reduced overshots, oscillations and ripple, enabling a smooth arrival to the steady state. The paper also proposes a strict Lyapunov function which enables the demonstration of asymptotic global stability of the closed-loop equation. In order to illustrate the performance and functionality of the proposed family of control schemes, an experimental comparison between seven control schemes was implemented. Five of these control schemes belong to the proposed family while two additional control schemes are well-known strategies such as the proportional-derivative (PD) and hyperbolic tangent (Tanh) control schemes. The experiments were performed by using a three degree-of-freedom, direct-drive robot manipulator. Palabras clave: Regulador, Función de saturación, Ganancia Variable, Manipulador robótico, Algoritmos de control, Keywords: Regulator, Variable gain, Robotic manipulator, Control algorithm

This paper presents an experimental platform for studying the effects of hardware vulnerabilities in mobile robots. The platform is designed so that the hardware, involved in the navigation process, can be monitored during the robot operation and, if desired, their behavior can be altered, allowing the simulation of a failure. The paper shows a particular case of study: the I2C Bus vulnerability when some anomalies appear in the clock signal. A set of experimental results confirm the interest of the studied vulnerabilities and the applicability of the developed platform.

Resumen: En este artículo se presenta un modelo dinámico para un recuperador de gases - sales fundidas incluido en una planta de demostración de una tecnología de hibridación de plantas termosolares con otras fuentes de energías renovables. Tanto el demostrador como el modelo se han desarrollado en el ámbito del proyecto HYSOL. Este trabajo describe brevemente dicho proyecto, su tecnología, demostrador y principalmente el modelo dinámico del recuperador, cuyo estado estacionario ha sido comparado con los cálculos de diseño. El artículo se completa con simulaciones dinámicas donde se estudia la convergencia del modelo, la contribución de los distintos procesos físicos a la transferencia de calor y el impacto de las condiciones ambientales a las pérdidas térmicas. Abstract: In this paper, a dynamic model of a molten salt -gas heat recovery system of a demonstrator for a hybrid renewable solar thermal power plant, developed in the scope of the HYSOL project, is presented. This work describes briefly the HYSOL project, its technology, the demonstrator and mainly the developed heat recovery system dynamic model; its steady state has been compared to the expected results from plant design calculations. This paper is completed with dynamic simulations where, the model convergence is studied, the contribution of the different heat transfer processes is analyzed, and the impact of the environment conditions to thermal losses is evaluated. Palabras clave: Almacenamiento térmico, Energía solar de concentración, Turbina de vapor, Turbina de gas, Modelica, Keywords: Thermal storage, Concentrating solar power, Steam turbine, Gas turbine, Modelica

Resumen: En este trabajo se presenta el desarrollo de un sistema de adquisición de datos y control altamente interactivo, de bajo costo, y basado en un computador personal. El sistema está constituido por un hardware basado en un microcontrolador y un software basado en estándares abiertos. El software utiliza programación de diagramas de bloques como base para el diseño teórico e implementación de un sistema de control, con la finalidad de hacer que la programación sea sencilla y rápida. Una característica importante del sistema es la capacidad de ejecutar control embebido sin la intervención del computador personal, lo cual permite control en tiempo real. Adicionalmente, tiene capacidad de ampliación para crear un sistema de monitoreo y control distribuido por medio del Bus CAN, como interfaz de comunicación. En este trabajo también se expone la implementación del sistema desarrollado en diferentes plantas. Abstract: In this paper, the development of a highly interactive, low-cost, and personal computer based data acquisition and control system is presented. The system includes an embedded microcontroller based hardware and an open-standards software. The software uses block diagram programming as the base for the theoretical design and implementation of the control system, which makes the programming simple and fast. An important feature of this system is that it can execute an embedded control without the personal computer intervention, which facilitates the implementation of real-time control. Additionally, the system has the capacity to expand in order to create a distributed monitoring and control system by using a CAN bus as a communication interface. It is also shown in this paper the implementation of the developed system in different plants. Palabras clave: Entornos de experimentación, Sistemas embebidos o empotrados, Microcontroladores, Sistemas de tiempo real., Keywords: Experimentation environments, embedded or built-in systems, microcontrollers, real-time systems.

This paper describes the analysis and modeling of an ultrasonic sensorial structure based on processing algorithm that uses a set of macro-sequences and correlation techniques for obtaining the impulse response of transmission channels simultaneously is proposed. The sensory structure is formed by multiple ultrasonic transducers that transmitting and receiving environment information simultaneously. This processing algorithm employs a pseudorandom macro-sequence obtained from a complementary set of M sequences (M- CSS) which, by auto-correlation and cross-correlation functions, the impulse responses from environment are obtained. The transmission in the ultrasonic system is represented by frequency selective MIMO model, which is analyzed every instant in the process of reflection-transmission-reception of the signals generated. Once the system model of ultrasonic transmission MIMO is developed and correlation algorithms are implemented for the detection of macro-sequences; the mathematical model, the results obtained in the simulation as well as experimental evidence are presented in this paper. These validate the use of the methodology applied to the channel modeling as well as the estimation of the impulse response of the transmission channels to process the received echoes corresponding to an object in front of the sensor system. The model implemented allows it on can develop algorithms and processing techniques, before they are physically implemented, in order to reduce application development time. In all such cases, is possible to obtain the impulse responses produced in the environment due to the reflectors located opposite the sensor system using correlation techniques.

Resumen: En el siguiente trabajo se presenta un sistema experto de control difuso (FLC), desarrollado para la búsqueda del punto de máxima potencia en módulos fotovoltaicos. Los FLC se utilizan ampliamente en diferentes sistemas de control, debido a que un diseño adecuado permite combinar velocidad y precisión en el control. En el trabajo se realiza un análisis a través del cual se definen las variables de entrada y el conjunto de reglas que utilizará el FLC. Tal análisis consiste en validar un modelo de módulo fotovoltaico-convertidor DC- DC y plantear simulaciones, en donde se observe la variación de potencia fotovoltaica a medida que el convertidor cambia el punto de trabajo. La respuesta del FLC desarrollado se observa en simulaciones en donde se modela los módulos fotovoltaicos y el transitorio que impone el convertidor DC-DC. Estas últimas ponen de manifiesto que el control propuesto es adecuado y superior al que ofrecen un sistema convencional de búsqueda. En el trabajo se presentan medidas que indican que la respuesta del FLC desarrollado es adecuada bajo diferentes condiciones de irradiancia y temperatura, verificando su correcto funcionamiento. La implementación física final del FLC propuesto, se realiza por medio de un microcontrolador PIC de 32 bits. Abstract: In this paper a fuzzy control expert system (FLC) is presented. Such system is developed for finding the maximum power point in photovoltaic modules. FLCs are widely used in various control systems, due to a suitable design which combines speed and accuracy in control. In the paper the input variables as well as the set of rules to be used in the control are defined. In such sense a photovoltaic module model - dcdc converter was validated in order to perform different simulations, to observe photovoltaic power variations in different operating points. The simulations show that the proposed control is suitable and better than a conventional system. Experimental measures indicate that the response of FLC developed under different conditions for irradiance and temperature are correct. The final physical implementation of FLC proposed is performed through a 32-bit PIC microcontroller. Palabras clave: Lógica Difusa, FLC, Boost, Fotovoltaico., Keywords: Fuzzy Logic, FLC, Boost, Photovoltaic.

Resumen: Este artÌıculo presenta un nuevo sistema de rehabilitacioÌn capaz de adaptarse al estado psicofisioloÌgico del paciente durante tareas de rehabilitacioÌn roboÌtica. Con este tipo de terapia se puede maximizar la motivacioÌn y participacioÌn del paciente durante la actividad de rehabilitacioÌn. En este trabajo se extienden los resultados del estudio presentado en (Badesa et al., 2014b), realizado con sujetos sanos, a su utilizacioÌn con pacientes que hayan sufrido un accidente cerebrovascular. En una primera parte del artÌıculo se presentan los distintos componentes del sistema adaptativo, y se realiza una comparativa de distintas teÌcnicas de aprendizaje automaÌtico para clasificar el estado psicofisioloÌgico del paciente entre tres estados posibles: estresado, nivel de excitacioÌn media y relajado. Finalmente, se muestran los resultados del sistema autoadaptativo con un paciente con ictus en fase croÌnica, que modifica el comportamiento del robot de rehabilitacioÌn y de la tarea virtual en funcioÌn de las medidas de las senÌales fisioloÌgicas. Abstract: This paper presents a new rehabilitation system that is able to adapt its performance to patient's psychophysiological state during the execution of robotic rehabilitation tasks. Using this approach, the motivation and participation of the patient during rehabilitation activity can be maximized. In this paper, the results of the study with healthy subjects presented in (Badesa et al., 2014b) have been extended for using them with patients who have suffered a stroke. In the first part of the article, the different components of the adaptive system are exposed, as well as a comparison of different machine learning techniques to classify the patient's psychophysiological state between three possible states: stressed, average excitation level and relaxed are presented. Finally, the results of the auto-adaptive system which modifies the behavior of the rehabilitation robot and virtual task in function of measured physiological signals are shown for a patient in the chronic phase of stroke. Palabras clave: Estado fisiológico, interfaces multimodales, robótica de rehabilitación, control., Keywords: Physiological state multimodal interfaces rehabilitation robotics control.

Resumen: Los invariantes generados a partir de momentos extraÌıdos de una imagen aparecen recurrentemente en la bibliografÌıa como uno de los meÌtodos maÌs potentes para la descripcioÌn de imaÌgenes, y maÌs concretamente de formas. En este artÌıculo se propone el uso de funciones de base continuas a intervalos (PCBF) como alternativa a las bases que se vienen utilizando tradicionalmente en la aplicacioÌn de este meÌtodo, todas ellas continas como puedan ser las muy conocidas de Zernike, Legendre o Tchebichev. El uso de funciones discontinuas se justifica en la naturaleza discontinua de los objetos analizados, en este caso las imaÌgenes: es de sobra conocido que los contornos de los objetos visibles en ellas se caracterizan como discontinuidades en la serie de valores de luminancia cuando nos desplazamos de un lado a otro de dichos contornos. El anaÌlisis de tales senÌales con funciones continuas produce resultados no deseados, como el fenoÌmeno de Gibbs, que pueden ser evitados mediante el uso de funciones como las propuestas, generando mejores aproximaciones a la forma analizada. Adicionalmente, las bases propuestas permiten faÌcilmente, como se demuestra, la generacioÌn de invariantes a rotacioÌn, caracterÌıstica altamente deseable para un descriptor de forma, puesto que a priori no se conoce con queÌ orientacioÌn apareceraÌ esta en la imagen objeto del anaÌlisis. La invarianza a traslacioÌn y escala se consigue mediante un sencillo proceso de normalizacioÌn. Se presentan los test que confirman esta hipoÌtesis, comenzando por un anaÌlisis del comportamiento de los invariantes ante el ruido en la imagen que permitiraÌ determinar en queÌ nuÌmero deben ser extraÌıdos. A continuacioÌn, y una vez definida esta longitud de descripcioÌn, se realizan sendos experimentos para determinar el comportamiento de los invariantes propuestos en una tarea de recuperacioÌn de imaÌgenes, tanto libres de ruido como corrompidas con distintos grados de ruido gaussiano. Los resultados avalan la hipoÌtesis de idoneidad para la tarea, demostrando que se pueden alcanzar resultados similares a los de la base de referencia, Zernike, utilizando descripciones hasta un 40% maÌs cortas. Abstract: Invariants generated departing from moments, previously extracted from an image, appear frequently in the bibliography as one of the most powerful means of describing images, and more precisely shapes. In this paper, the use of Piecewise Continuous Basis Functions (PCBF) is proposed as an alternative to those basis which have been used traditionally in the method of moments, all of them continuous as the well known Zernike, Legendre or Tchebichev basis. The use of discontinuous basis can be justified by the own discontinuous nature of the object of such analysis, namely images: it is thoroughly known that the contours of visible objects are modeled as discontinuities in the series of luminance values as we go from one side of the border to the other. Analyzing such discontinuous objects by means of continuous functions can lead to undesired results, as the Gibbs phenomenon, that can be avoided by simply shifting to discontinuous basis for the analysis, getting better approximations to the described object. Additionally, the proposed basis can easily generate, as shown in this paper, rotation invariants, which is a very desirable feature for a shape descriptor, given that the orientation that the shape will have in an image is not known in advance. Translation and scale invariance is obtained by means of a simple normalization process. Test confirming this hypothesis are presented as well, starting with an analysis of the behavior of the proposed invariantes in noisy environments, which allow to fix the number of invariants that have to be extracted. Next, once this description length has been determined, new experiments are carried out to assess the performance of the proposed invariants in a content based retrieval task, both in a noise free and in noisy environments, having images corrupted with different gaussian noise intensities. Results confirm our hypothesis that these descriptors are very well suited for this task, showing that they can achieve results similar to those obtained using the continuous reference basis, which is Zernike's, but with a description which is roughly a 40% shorter. Palabras clave: Método de los momentos, descriptores invariantes, bases ortonormales, recuperación basada en contenido, análisis de imágenes, Keywords: Method of moments, invariant descriptors, orthonormal basis, content based image retrieval, image analysis

Resumen: El objetivo principal de este artículo es presentar los métodos más habituales de aprovechamiento de distintos tipos de energías renovables procedentes del mar y analizar los modelos energéticos de los dispositivos utilizados para su explotación. Estos modelos son necesarios para el diseño del dispositivo así como para el estudio de su comportamiento dinámico. Su conocimiento resulta imprescindible también para su simulación dinámica y para el diseño de los algoritmos de control necesarios para conseguir una optimización energética y económica. En este trabajo se presentan algunos de los diferentes tipos de energías del mar, y se j ustifica el interés en el desarrollo de dispositivos específicos para el aprovechamiento de las corrientes marinas y de las olas, junto con una pequeña clasificación en función de la profundidad del agua en la zona de instalación de estos dispositivos. Para los convertidores de energía de las olas, generalmente, de tipo resonante, se presenta una metodología de tipo general, analizando los distintos campos de fuerzas actuantes y los métodos de obtención de las respuestas temporal y frecuencial. Para los dispositivos de aprovechamiento de las corrientes, se propone una metodología simplificada de modelado dinámico que puede ser utilizada en análisis del dispositivo concreto. Para ello se tiene en cuenta los perfiles hidrodinámicos que utilizan estos dispositivos, los datos del perfil de la corriente con la profundidad y del modelo de oleaje, y la dinámica propia del conjunto multiplicadora y generador eléctrico. La metodología propuesta se aplica al estudio de un caso concreto, correspondiente a un rotor de eje horizontal de un convertidor de energía de las corrientes. Los resultados obtenidos permiten analizar los efectos del oleaje y de las condiciones de flujo de la corriente no uniforme sobre las magnitudes energéticas más importantes. Abstract: The main objective of this paper is to present the most common harnessing methods for different types of renewable energy from the sea, and to analyze energy models of the devices used for their exploitation. These models are required for the design of the device as well as for the studying of their dynamic behavior. The knowledge of these models is also necessary for dynamic simulation and for the design of control algorithms in order to achieve energy and economic optimizations. In this paper, some of the different types of ocean energy are presented and the interest in the development of specific devices for the exploitation of sea currents and waves is justified. A small classification based on the depth of water in the area where these devices are to be installed is presented too. For wave energy converters, which are generally resonant type, a general methodology is presented. The different fields of acting forces and methods for obtaining the time and frequency responses are analyzed. For devices for the exploitation of energy from sea currents, it is presented a simplified methodology of dynamic modeling that can be used in analysis of the particular device. It is taken into account the hydrodynamic profiles used in these devices, the data flow profile with depth and wave model together with the gearbox-generator set dynamics. The proposed methodology is applied to a specific case study, corresponding to a horizontal axis rotor from a device for harnessing of tidal energy. The obtained results allow to analyze the effects of wave and flow conditions of non uniform current over the most important energy variables. Palabras clave: energías renovables marinas, modelado y simulación, teoría del elemento de pala, modelado del recurso, absorbedor puntual, Keywords: marine renewable energies, modelling and simulation, blade element theory, resource modelling, point absorber

Resumen: La lógica borrosa ha conseguido en un breve periodo de tiempo revolucionar la tecnología mediante la conjunción de los fundamentos matemáticos, la lógica y el razonamiento. Su inherente capacidad de hibridación y su robustez intrínseca han permitido a la lógica borrosa cosechar numerosos éxitos en el campo del modelado y el control de sistemas, impulsando el control inteligente. En este artículo se estudian los sistemas borrosos híbridos más usuales y su importancia en el campo del modelado y control de sistemas dinámicos. El trabajo presenta varios ejemplos que ilustran, para diferentes técnicas de hibridación, cómo éstas potencian las cualidades innatas de la lógica borrosa para el modelado y control de sistemas dinámicos. Así mismo, se incluyen más de ciento cincuenta referencias bibliográficas que permitirán al lector interesado profundizar en el campo de la lógica borrosa, y más concretamente en el de sus técnicas de hibridación con aplicación al modelado y control borroso. Abstract: Fuzzy logic has revolutionized, in a short period of time, the technology through a combination of mathematical fundamentals, logic and reasoning. Its inherent hybridization ability and intrinsic robustness, have allowed to fuzzy logic get numerous successes in the field of modeling and control of systems, impulsing the intelligent control. In this paper, the more usual hybrid fuzzy systems and its importance in the field of modeling and control of dynamic systems are studied. The paper presents several examples that illustrate, for different hybridization techniques, how these enhance the innate qualities of fuzzy logic for modeling and control of dynamic systems. Also, more than a hundred and fifty references are included, which allow the interested reader to delve into the field of fuzzy logic, and more specifically, in its hybridization techniques with application to modeling and fuzzy control. Palabras clave: Algoritmos bioinspirados, control borroso, control inteligente, modelado borroso, redes neuronales, sistemas borrosos, sistemas híbridos, Keywords: Bioinspired algorithms fuzzy control fuzzy modeling fuzzy systems hybrid systems intelligent control neuronal networks

Resumen: Las técnicas de asignación de autoestructuras (Eigenstructure Assignment â EA) han sido aplicadas con éxito al diseño de controladores en diferentes sectores industriales durante las últimas décadas. En este artículo se presentan los aspectos más interesantes del método general y de las técnicas de asignación comúnmente utilizadas. Los métodos de asignación son considerados como técnicas de control modal, por lo que en el diseño de controladores aplicado a cualquier sistema se infiere un análisis de los modos del mismo. Se incluye una revisión de las aplicaciones más interesantes sustentada por los trabajos realizados por numerosos autores. En particular, se introduce una aplicación concreta de los métodos de asignación de autoestructuras al sector aeroespacial. Abstract: The methods based on Eigenstructure Assignment (EA) have been applied to the successful design of controllers in different industrial application over the last decades. In this paper the most interesting aspects of the EA methods are reviewed. The EA methods are considered by control researchers as a modal method. The paper also includes a review to the literature related to aerospace applications and EA controllers design. A numerical example is included in this work to show the whole process taken to design a static controller applied to a spacececraft. Palabras clave: Control aeroespacial, asignación de autoestructuras, desacoplo dinámico, Keywords: Aerospace control, Eigenstructure assignment, Dynamic decoupling

Resumen: Este artículo aborda el problema de seguimiento de trayectoria de un aerodeslizador subactuado. Esta clase de sistemas es difícil de controlar debido a que su movimiento está sujeto a una restricción no holonómica de segundo orden. La resolución de este complejo problema requiere la descomposición de la dinámica del sistema en dos subsistemas (posición y orientación) para los que se diseña una ley de control basada en dos controladores no lineales en cascada. El lazo externo de control calcula los valores de la fuerzas en el sistema inercial Fx y Fy que deberían aplicarse al aerodeslizador para seguir la trayectoria deseada. A partir de estas fuerzas se determina la referencia para la orientación, Ïc, entrada del lazo interno. Por su parte, el lazo interno intenta controlar la orientación para de esta forma seguir las referencia Ïc del lazo externo. Ambos controladores se han diseñado teniendo en cuenta la saturación de los actuadores. En particular, el principal resultado de este artículo muestra que en los casos donde la trayectoria está adecuadamente definida, es posible ajustar los parámetros del controlador para evitar la saturación de los actuadores. Este trabajo demuestra de forma teórica la estabilidad asintótica global del error de seguimiento bajo la acción del controlador propuesto. Además, mediante simulaciones, se analiza el comportamiento del sistema y el significado práctico de los resultados teóricos. Abstract: This paper deals with the interesting problem of trajectory tracking of an underactuated hovercraf. This system is difficult to control because it exhibits second order nonholonomic restrictions on its movement. In order to solve the control problem the dynamics of the system is discomposed in two subsystems (one for position and another for orientation) and a nonlinear control law based on two nonlinear cascaded controllers is designed. On one hand the outer, loop computes the forces that are necessary to track the spatial trajectory Fx and Fy in the inertial frame. Based on this forces, the reference for the orientation Ïc is computed and it is feedback to the inner loop. On the other hand, the inner loop tries to converge the orientation to the reference Ïc given by the outer loop. Both controllers are designed taking into account saturation of the actuators. In fact the main result of this paper shows that if the reference trajectory is given properly it is possible to avoid saturation of the actuators. With adequate selection, global asymptotic stability of the tracking error under the proposed control law is theoretically demonstrated. In addition simulations are made in order to analyze the performance of the control law and the practical meaning of the theoretical results. Palabras clave: Control no Lineal, seguimiento de trayectoria, vehículo subactuado, saturación, vehículo autónomo, Keywords: Nonlinear control, trajectory tracking, underactuated vehicle, saturation, autonomous vehicles

Resumen: El presente documento discute la estrategia bajo la que fueron concebidas la arquitectura de hardware y software para el prototipo de vehículo autónomo: HRC-AUV, así como la selección de los elementos fundamentales que las componen. El diseño obtenido pondera la sencillez y el desarrollo en condiciones de bajo costo, factores útiles a investigadores que comienzan su actividad en este campo. El trabajo resume las prestaciones que brindan dichas estructuras y las pruebas preliminares de operatividad a que han sido sometidas para demostrar la validez de su empleo en la explotación de un AUV. De igual forma se presentan los modelos dinámicos linealizados de la planta, utilizados en la sintonía de los lazos de control. La respuesta de dichos lazos y en general del HRC-AUV navegando en el océano, es presentada a través de los resultados obtenidos en varias pruebas experimentales. Abstract: This paper discusses the strategy under which were conceived the hardware and software architecture for autonomous vehicle prototype: HRC-AUV, and the selection of the fundamental elements that compose them. The obtained design weights simplicity and development in terms of low cost, factors useful to researchers begin their activity in this field. The paper summarizes the benefits provided by these structures and preliminary operational tests that have been submitted to demonstrate the validity of their use in the operation of an AUV. Likewise are linearized dynamic models of the plant, used in the tuning of the control loops are presented. The response of such loops and in general the HRC-AUV navigating in the ocean is presented through the results of several experimental tests. Palabras clave: AUV, arquitectura de hardware, arquitectura de software., Keywords: AUV, hardware architecture, software architecture.

Resumen: El propósito de este artículo es efectuar una revisión del estado del conocimiento en el modelado y control de los sistemas de suspensión activa y semiactiva. Se analizan las principales características de los diferentes tipos de sistemas de suspensión: pasiva, activa y semiactiva. Respecto al modelado y simulación de los sistemas de suspensión, se examinan los distintos enfoques, herramientas y aplicaciones en el contexto de la dinámica vehicular. Además, para el modelo de un cuarto de vehículo, ampliamente utilizado en la literatura, se ofrece su desarrollo mediante ecuaciones diferenciales, función de transferencia, y ecuaciones de estado, incluyendo soluciones y simulaciones en Simulink y SimMechanics. En cuanto al control, se revisan las principales estrategias para la suspensión de vehículos y se apuntan aplicaciones en otros campos de la ingeniería. Abstract: This paper reviews the state of the art in modeling and control of active and semi-active suspension systems. Distinctive characteristics are established for the major types of suspension systems: passive, active, and semi-active. Regarding modeling and simulation, different approaches, tools and applications are discussed in the context of vehicle dynamics. Besides, the quarter car model, which is widely used in research, is developed with differential equations, transfer functions, and state-space equations, as well as solutions for simulation in Simulink and SimMechanics. As for control of active and semi-active systems, the major strategies for vehicle suspension are reviewed. Furthermore, the paper outlines suspension control in other engineering applications. Palabras clave: Simulación, Suspensión activa, Modelos, Suspensión pasiva, Robótica, Keywords: Active suspension, Passive suspension, Models, Control

Resumen: En este trabajo se aborda el diagnóstico de eventos o perturbaciones de tensión registradas en subestaciones de distribución. La aparición de dichos eventos se debe a causas diversas que van desde faltas en la red, el arranque de motores de inducción, energización de transformadores y conmutación de bancos de capacitores. Se propone la caracterización de estos eventos de tensión a partir de atributos extraídos directamente de la forma de onda, y que se relacionan con los fenómenos físicos asociados tanto con las causas de los eventos, como con su localización relativa respecto del punto de medida. Se ha estudiado la relevancia de dichos atributos mediante un análisis estadístico de la varianza (MANOVA). Los atributos más relevantes se han utilizado para la obtención de reglas de clasificación mediante algoritmos de aprendizaje automático. Los resultados fueron obtenidos empleando datos de 484 eventos reales y 38 eventos simulados. Abstract: This paper focuses on diagnosis of voltage events collected in power distribution networks. Fault networks, induction motor starting, transformer energization and capacitor bank switching cause voltage events. A characterization of voltage events using attributes directly extracted from the voltage and current waveforms is done in this paper. The used attributes are highly related with the event root-cause as well as the relative location of the event source with respect to the measurement point. The relevance of each attribute has been assessed applying a statistical analysis of variance (MANOVA). The most relevant attributes have been used as input to rule-extraction algorithms in order to extract classification rules. The results were obtained using 484 real-world and 38 synthetic voltage events. Palabras clave: Análisis estadístico, Calidad de la potencia eléctrica, Atributos, Eventos de tensión, Sistema basado en reglas, Keywords: Statistical analysis, power quality, attributes, voltage sag event, rule based system

Resumen: En este artículo abordamos el problema de la construcción del mapa visual de un entorno mediante un robot móvil, ubicándose, por tanto, en el ámbito del problema de SLAM (Simultaneous Localization and Mapping). La solución presentada en este artículo se fundamenta en el uso de un conjunto de imágenes para representar el entorno. De esta manera, la estimación del mapa se plantea como el cálculo de la posición y orientación de un conjunto de vistas omnidireccionales obtenidas del entorno. La idea desarro- llada se separa de la concepción habitual de mapa visual, en la que el entorno estárepresentado mediante un conjunto de puntos tridimensionales definidos respecto de un sistema de referencia. En el caso presentado, se considera que el robot estáequipado con un único sensor visual omnidireccional que permite detectar un conjunto de puntos de interés de las imágenes que, a continuación, son representados mediante un descriptor visual. El proceso de construcción del mapa se puede resumir de la siguiente manera: cuando el robot se mueve por el entorno captura imágenes omnidireccionales y extrae un conjunto de puntos de interés de cada una de ellas. A continuación, se buscan correspondencias entre la imagen capturada y el resto de imágenes omnidireccionales existentes en el mapa. Si el nú mero de correspondencias encontradas entre la imagen actual y alguna de las imágenes del mapa es suficiente, se calcula una transformación consistente en una rotación y translación. A partir de estas medidas podemos deducir la localización del robot con respecto a las imágenes almacenadas en el mapa. Se presentan resultados obtenidos en un entorno simulado que validan la idea presentada. Además, se han obtenido resultados experimentales utilizando datos reales que demuestran la validez de la solución presentada. Abstract: This paper deals with the problem of Simultaneous Localization and Mapping (SLAM). The solution presented is based on the utilisation of a set of images to represent the environment. In this way, the estimation of the map considers the computation of the position and orientation of a set of omnidirectional views captured from the environment. The proposed idea sets apart from the usual representation of a visual map, in which the environment is represented by a set of three dimensional points in a common reference system. Each of these points is commonly denoted as visual landmark. In the case presented here, the robot is equipped by a single omnidirectional visual sensor that allows to extract a number of interest points in the images, each one described by a visual descriptor. The map building process can be summed up in the following way: as the robot traverses the environment, it captures omnidirectional images and extracts a set of interest points from each one. Next, a set of correspondences is found between the current image and the rest of omnidirectional images existing in the map. When the number of correspondences found is enough, a transformation is computed, consisting of a rotation and a translation (up to an unknown scale factor). In the paper we show a method that allows to build a map while localizing the robot using these kind of observations. We present results obtained in a simulated environment that validate the proposed idea. In addition, we present experimental results using real data that prove the suitability of the solution. Palabras clave: SLAM, robótica móvil, visión omnidireccional, Keywords: SLAM, mobile robotics, omnidirectional vision

Resumen: Los ìndices de desempeño son importantes herramientas para la planificación de movimientos y el diseño de robots manipuladores. En este trabajo se presenta una colección de algunos de los ìndices de desempeño que mayor interés han generado en la comunidad dedicada a la robótica. Se presentan ìndices de desempeño cinetostático, dinámico, de lìmites articulares, e ìndices definidos sobre el espacio de trabajo. Además, se realiza una revisión sobre las estrategias que se han propuesto para solventar los problemas que aparecen cuando las unidades de los elementos de la matriz Jacobiana no son homogéneas. Al final de este trabajo, proponemos una serie ìndices de desempeño globales que pueden resultar útiles en el diseño de robots manipuladores. Abstract: The performance indices are important tools for motion planning and design of robot manipulators. In this paper we present a collection of some of the performance indices that have generated interest in the robotics community. These indices are four different types: kinetostatic performance indices, dynamic performance indices, indices of joint limits, and finally global performance indices. In addition, we review the strategies that have been proposed to solve the problems that occur when the units of the Jacobian matrix elements are not homogeneous. At the end of this paper, we propose a set of global performance indices that can be useful in the design of robot manipulators. Palabras clave: Ìndices de desempeño, Cinetostático, Dinámico, Limites Articulares, Globales, Keywords: Performance Indices, Kinetostatic, Dynamic, Joint Limits, Global

Resumen: En este trabajo se presenta el desarrollo de un robot basado en la estructura Pre-Tensada con el fin de realizar tareas de inspección y mantenimiento en tuberías petroleras. Este tipo de estructura mecánica se caracteriza por su bajo peso y su alta capacidad de adaptación a los diferentes diámetros.La aplicación requiere que el dispositivo desarrollado se desplace verticalmente y a alta velocidad por las tuberías utilizadas en la extracción del petróleo. Cabe destacar que en dichas instalaciones se cuenta con Bombas Electro Sumergibles (BES) y Bombas de Cavidad Progresiva (BCP), ambas muy sensibles a las condiciones adversas del entorno; por lo tanto, la importancia de esta investigación radica en que el robot incorpora una red de sensores específicos para medir aquellas variables que puedan interferir en el funcionamiento normal de las bombas. Además, este robot permite automatizar la recuperación de objetos que pueden caer al pozo durante la instalación y mantenimiento del mismo, actualmente este proceso es manual.En este artículo se describen detalladamente las hipótesis de diseño realizadas y la metodología utilizada para el desarrollo del primer prototipo. Finalmente se presentan los resultados obtenidos de dicho desarrollo a través de los cuales se ha podido validar la potencialidad de la aplicación. Abstract: This paper presents the development of a robot based on the prestressed structure to carry out maintenance inspection on oil pipelines. This type of mechanical structure is characterized by low weight and high capacity of adaptation to different diameters. The application requires the device to move vertically and developed high-speed. Note that in such facilities with electric submersible pumps (ESP) and Progressive Cavity Pumps (BCP), both highly sensitive to adverse environmental conditions, therefore, the importance of this research is that the robot incorporates a specific sensor network to measure those variables that can interfere with the pumps normal operation. In addition, this robot can recover objects that could fall into the well during installation and maintenance activities, this process is currently manual.This paper describes in detail the design hypothesis and the methodology used to develop the first prototype. Finally, we present the results of such development through which it has been able to validate the potential of the application. Palabras clave: Pre-Tensada, Robot Tubería Vertical, Bombas Electro Sumergible, Bomba de Cavidad Progresiva, Keywords: Pre-tensioned, Robot Vertical Piping, electrical Submersible Pumps, progressive cavity pump

Presently, electric power systems based on microgrids are reaching an important position in different locations around the world. The multiple distributed generation technologies employed in modern microgrids allow a joint operation of renewable and non-renewable energy sources with many types of loads. Nonetheless, induction motor (IM) type dynamic loads represent one of the most critical factors that make microgrid systems vulnerable to scenarios that could trigger voltage instability. This paper proposes the incorporation of FACTS (flexible ac transmission system) devices to improve the dynamic voltage stability of microgrids with high dynamic load penetration. The work focuses on the impact of including a DSTATCOM (distribution static compensator) in a microgrid with high IM type dynamic load penetration when a fault occurs that causes the microgrid isolation. Various case studies are analyzed using the CIGRÉ microgrid test system. The results show the improvements in the voltage stability of the microgrid with the coordination of distributed generation technologies and the DSTATCOM.

Pitch control of wind turbines is complex due to the intrinsic non-linear behavior of these devices, and the external disturbances they are subjected to related to changing wind conditions and other meteorological phenomena. This difficulty is even higher in the case of floating offshore turbines, due to ocean currents and waves. Neural networks and other intelligent control techniques have been proven very useful for the modeling and control of these complex systems. Thus, this paper presents different intelligent control configurations applied to wind turbine pitch control. Direct pitch control based on neural networks and reinforcement learning, and some hybrid control configurations are described. The usefulness of neuro-estimators for the improvement of controllers is also presented. Finally, some of these techniques are used in an application example with a land wind turbine model.

This paper presents a bio-inspired hybrid algorithm for shape detection applicable to solar estimation in solar power plants. The objective is to locate and characterise the shape of a cloud over a solar power plant based on low level irradiance measurement with a small fleet of Unmanned Aerial Vehicles (UAVs) equipped with direct normal irradiance sensors. Toe hybrid algorithm takes inspiration and adapts ideas of the ant colony optimisation algorithm (ACO) and also uses a standard cover area algorithm, separating the field into two grids, one for each layer of the algorithm, to find the area affected by the cloud. Once the low irradiance zone is located by one of the UAVs, the others go to help it. This team delimits the cloud border using concepts of an image processing technique. Finally, the algorithm is tested by simulations.

In this paper, a control scheme to regulate the speed in an electric vehicle with two electric motors in the rear axle. In order to make a turn in the vehicle a differential speed in the motors is needed. A detailed mathematical model of the electric vehicle is included, comprising the dynamics of the components in the system, as well as their interconnections. An inverse kinematic controller is presented to calculate the required speed references for the motors. Taking into account the references, a robust sliding mode controller is presented, to guarantee the stability of the complete system. The proposed control scheme was tested in closed - loop through simulations to prove the performance. The results show a good performance under different perturbations, such that parameter variations and external disturbances, in this case, driver mass and road slope. Furthermore, the discretization and a proposal to implement the control scheme controller in an embedded system are presented.

Time synchronization is a key requirement in several application domains based on real-time distributed systems. Therefore, it is a research area of interest, especially in lines such as the transfer of time and frequency, the design of clocks and oscillators, and the use of synchronization in communication networks. This work focuses on the transfer of time between elements of a distributed system for the synchronization of their clocks and the software they execute. Currently, there are different protocols to synchronize autonomous nodes, but they have some drawbacks that make them unsuitable for certain types of distributed systems. This paper presents a method for synchronizing the execution of distributed software on a local area network. Additionally, the functional safety analysis of the method is developed and the measures it must implement to achieve a SIL2 are proposed. The method has been implemented and validated by executing it in a realistic physical distributed system, obtaining promising results.

A robotic exoskeleton is an electromechanical device that can be worn by a person to increase its physical capacity, to assist locomotion or for gait rehabilitation processes. In the case of rehabilitation exoskeletons, the control system is required to be smooth and capable to match accurately with the patients’ evolution in order to optimize the eciency of their recovery, this implies the design of robust and precise controllers. In this paper, kinematic analysis, dynamic analysis and control system evaluation for ALICE rehabilitation exoskeleton is presented. Among the control techniques used are: the PD controller, adaptive PD, and the sliding mode controller. In addition, a stability analysis using the Lyapunov criterion is performed. To test the performance of the controllers, gait data obtained by the ONCE School of Physiotherapy in Madrid, which correspond to healthy people and people with multiple sclerosis, are used. MATLAB as simulation software and programming language is used.

This manuscript presents a general overview of the microalgae production process from a modelling and control perspective. First, the main advantages and the potential of these microorganisms are motivated, describing the dierent type of reactors used for their cultivation. Afterwards, the process dynamics, which is very complex and variable due to diary and annual changes on ambient conditions, is analyzed and the main balance equations to describe the system behaviour are introduced. Then, dierent biological and structural models validated in industrial plants will be presented. Subsequently, the existing control problems in these systems are described, introducing a wide set of control algorithms that have been experimentally evaluated in industrial reactors. Finally, the most relevant aspects discussed along the paper are summarized.

This paper is a follow-up to previous researches already published regarding the minimization of optical-electrical noise in optical scanning systems OSS, by the implementation of computational techniques for pattern recognition generated by each reference source used to indicate a coordinate that the OSS will be monitoring. Techniques such as linear discriminant analysis LDA and linear regression LR were implemented in order to discriminate the signals caused by other sources different to the references. In order to enhance the efficiency of these models was implemented linear predictive coding LPC and quantiles as features extractors. The results were encouraging with rates of recognition greater than 91.2 %, reaching in some cases an accuracy of 100 %.

Production systems have evolved in the last years thanks to the recent technological advances and innovations in the manufacturing process. The Industry 4.0 term has become a priority and object of study for companies, research centers and universities, but there is not a generally accepted consensus for the term. As a result, is difficult design and implementation appropriate Industry 4.0 solutions at academic, scientific or business level. The contribution of this paper focuses on providing an analysis of Industry 4.0 meaning and implications and exposes in detail 17 fundamental design principles obtained by a systematic mapping study method. These principles are efficiency, integration, flexibility, decentralization, personalization, virtualization, security, is holistic, ubiquitous, collaborative, modular, robust, use information in real time, makes optimized decisions driven by data, is service-oriented, work life balance and is autonomous and intelligent. With these design principles, engineers and researchers have the capacity to research and implement appropriate Industry 4.0 scenarios.

Membrane distillation is a termally-driven separation process under investigation. This technology stands out for the simplicity of the process and for its low operating temperature, which allows it to be combined with low grade solar energy. Thus, membrane distillation has become a promising, effcient and sustainable solution for the development of small-medium stand-alone desalination facilities to be implemented in offgrids areas with good irradiance conditions. However, in order to develop this technology on an industrial scale, research must continue to improve aspects related to both the design of membranes and modules and their operation. Regarding the operation, the development of models and control techniques play a fundamental role. This paper presents a review of the control and modeling techniques applied in this field, describing the main methodologies employed and the future challenges to be addressed, also including an illustrative example.

Typically, the control scheme of the active power filter corresponds to a cascade controller, which consists of an outer loop for dc voltage regulation and an inner loop for the tracking of a reference current. Each control loop must be associated with controllers that allow a fast convergence to the established references. This paper presents a cascade controller for active power filter applications, employing a proportional-integral (PI) controller for the external loop, and the super-twisting algorithm (STA) for the internal loop, where the union of both controllers is called PI-STA cascade controller. On the one hand, a step response analysis for the estimation PI gains is carried out. On the other hand, the STA tuning takes place from considering the similarity between the structures of STA with a PI. In order to validate the methodology tuning consistency simulation and experimental results are presented.

This paper deals with the development of a decentralized event-based control strategy applied to the leader-following consensus problem of a group of two-wheeled self-balancing robots so called mobile inverted pendulum (MIP). The MIP’s nonlinear mathematical model which includes the dynamics of the actuators is presented. Then, the model around an operating point is considered which allows to exploit the differential flatness property of the system, permitting a complete parametrization in terms of the flat output. Assuming that the vehicle network exchange information through a directed and strongly connected graph, a decentralized control law is designed, and an event-based algorithm is developed. Then each MIP decides, based on the difference of its current state and its latest broadcast state, when it has to send a new value to its neighbors. The stability of the complete system is carried out in the Lyapunov sense together with the ISS (Input-to-State Stability) approach. Numerical results show the advantages \textit{wrt} information exchange between MIPs, as well as a good performance in the angular stabilization under two scenarios: regulation and tracking problem.

In this paper a dynamic model of a battery that lets simulate different types of batteries in light electric urban vehicles applications is proposed. The model is directly parameterizable from discharging experimental curves in test facilities. It properly fits to the particular behaviour observed in the charging/discharging curves in LiFePo 4 batteries. For the calibration of the proposed model experimental data from an experimental facility have been used and validation results are presented. The model is implemented in the object oriented modelling language Modelica reusing classes from the Modelica Standard Library. The calibration and the calibration has been performed with Dymola modelling tool.

Android is the most extended operating system in the field of smartphones. Its wide diffusion has caused a great interest in using it in real time environments. This paper presents a mechanism to use the Ada programming language for real-time applications on Android. Ada is a language that offers support for environments with real-time requirements under the assumption that the execution platform provides the necessary guarantees on response time. To accomplish these guarantees, we propose that applications written in this language use the isolation mechanisms provided by the Android/Linux operating system through which it is possible to isolate one or several processor cores to use them exclusively with real-time Ada applications. In addition, we have studied the available mechanisms in Android to share data between these isolated real-time Ada applications with other applications executing in the same system.

A new conception in the development of Electronic Control Units (ECUs), which are also called On-Board Units (OBUs), is discussed in this paper from an ontological vision oriented to the compatibility of vehicles with future technologies in the automotive field. This work also provides a new methodology in the design of On-Board vehicle units. The proposed technique is based on the concept of modular electronic units that can change their functionality depending on the modules they are consisted of. The study was initially designed at the theoretical level, analysing the problems in the sector in the face of the coexistence between vehicles today and those that are bound to appear in the near future, and that will incorporate capabilities making them connected and even autonomous. Additionally, a fully operational prototype has been developed so as to ascertain the possibilities of the proposed solution.

In this paper we present a novel cross-layer medium access control scheme that uses information about the network topology in order to select the adequate transmission probability at the individual nodes. In the proposed Entropy-based Medium Acess Control protocol (EbMAC), the probability of accessing the channel of each node is a function of the topological network entropy and their individual probability of being selected as relay in an end-to-end path computed by the routing algorithm. The topological network entropy measures the ability of the network to distribute the data traffic among the nodes. High values of network entropy indicate that the data trac will tend to concentrate around particular regions of the network and hence, that these regions are more likely to experience contention. In this case, the channel access probability has to be selected in such a way as to reduce the packet collision probability in such hot spots. Simulation-based experiments show that the proposed scheme attains performance gains in terms of throughput, collisions ratio and end-to-end delay.

This paper presents a tutorial on analysis and design of linear parameter varying (LPV) systems using linear matrix inequalities (LMIs). Several specifications, such as D-stability, guaranteed H∞ performance and guaranteed quadratic cost, as well as different control structures, such as state-feedback control, output-feedback control and observer-based control, are considered. A numerical example and a simplified model of a two-degrees-of-freedom helicopter (TRMS) are used to illustrate in a didactic manner the overall design methodology using LMIs.

Reliability is considered a fundamental requirement of some variable-speed electric drives. Therefore, multiphase systems, which introduce a higher fault tolerance than conventional three-phase ones, turn out to be an interesting alternative for these applications. This high fault-tolerant capability is obtained thanks to the higher number of freedom degrees. This paper presents a direct torque control strategy based on virtual voltage vectors when an open phase fault appears in a six-phase induction machine. These virtual voltage vectors reduce the copper losses due to x-y current components. Experimental tests have been provided to validate the control strategy.

Control of multi-phase induction machines is evolving with the incorporation of predictive controllers that operate directly with the power converter without modulators. It is realized in discrete-time through an exhaustive optimization of the inverter states. The optimization uses a cost function that penalizes deviations from the reference and other undesired factors. The cost function design has a big impact on closed loop performance. In this paper, a new strategy for cost function design is presented as a contribution. The strategy defines and a performance index relative to the observed behavior. The cost functions are derived from an optimization of said index. Experimental and simulation results are included for a five-phase induction machine with a comparison with previous methods in the context of predictive current control.

This paper presents a methodology for the tuning of the parameters of a nonlinear model based predictive controller (NMPC) based on an optimization technique, applied in the control of nonlinear chemical processes, with the purpose of facilitating the stage of determination of the adjustment values of this type of control strategies. The results allow to determine the performance of the NMPC tuned with the methodology proposed and validate the results with tunings developed through other strategies. The proposed methodology is applied to the control of the concentration of a reagent in a continuously stirred tank reactor (CSTR).

The use of distribution middleware facilitates the programming of heterogeneous real-time distributed systems, and it can also facilitate the automatic generation of source code when integrated as a part of a general MDE (Model-Driven Engineering) strategy. However, the complexity usually associated with distribution middleware puts a burden on the development of applications with hard real-time requirements or high levels of criticality. This paper gathers a set of previous works to present an overview on how a data-centric distribution middleware (DDS, Data Distribution Service) could be used in distributed applications with mixed criticality and real-time requirements.

This paper presents a framework for teaching robotics at engineering university degrees in a practical way. It is open source, multiplatform (Linux, Windows, MacOS) and emphasizes the programming of the robot intelligence. It consists of a collection of exercises of several types, which are similar to the new robotic applications (autonomous vehicles, drones, vacuum cleaners...). It uses the Gazebo simulator and the Python programming language. For each exercise an academic application has been created which performs all the auxiliary tasks like graphical interface, connection to the sensors and actuators, timing of the code, etc. and hosts the student’s code, who can focus on the perception and control algorithms. Each academic application combines an infrastructure part, which it is provided and remains hidden, and the student part, who simply fills a form file with the robot logic for such exercise. It has been successfully used in several subjects at engineering degree, master and robotics introductory courses.

In this paper we present the Linear Image Combination Algorithm with Variable Windows (CLI-VV) for the fusion of multifocus images. Unlike the CLI-S algorithm presented in a previous work, the CLI-VV algorithm allows to automatically determine the optimal size of the window in each pixel for the segmentation of the regions with the highest sharpness. We also present the generalized CLI-VV Algorithm for the fusion of sets of multi-focus images with more than two images. This new algorithm is called Variable Windows Multi-focus Fusion (FM-VV). The CLI-VV Algorithm was tested with 21 pairs of synthetic images and 29 pairs of real multi-focus images, and the FM-VV Algorithm on 5 trios of multi-focus images. In all the tests a competitive accuracy was obtained, with execution times lower than those reported in the literature.

Image binarization is a basic image processing technique with many applications. Binarization methods have been incrementally improved to deal with real world conditions. A particularly important consideration is non-uniform illumination, present when using general purpose devices for image acquisition (e. g. mobile phones). In this paper we present a new binarization method for non uniformly illuminated text images. The main idea is to improve illumination using two complementary illuminated images. To achieve this we estimate the luminance of the original image and we create a new complementarily illuminated image.We then fuse the two images and for each pixel we estimate in which of the two images the pixel is correctly illuminated. The proposed method is evaluated with synthetic and real images, using several metrics, showing better performance than state-of-the-art techniques.

This paper presents the design and implementation of robust controller for DC/DC Buck–Parallel Converter under the perspective of differential flatness and active disturbance rejection control based on extended state observer or GPI. The main goal is to obtain a regulated output voltage and balance of currents for parallel converters. Control law was implemented on the Nexys 4 development board with an Artix-7 FPGA to evaluate controller performance. For this, laboratory tests were performed subjecting the converter to unknown external perturbations and variations in time and changes in the parameters of the system, counteracting the effects of these perturbations.

Currently, many applications require a precise localization of the objects that appear in an image, to later process them. This is the case of visual inspection in the industry, computer-aided clinical diagnostic systems, the obstacle detection in vehicles or in robots, among others. However, several factors such as the quality of the image and the appearance of the objects to be detected make this automatic location difficult. In this article, we carry out a systematic revision of the main methods used to locate objects by considering since the methods based on sliding windows, as the detector proposed by Viola and Jones, until the current methods that use deep learning networks, such as Faster-RCNN or Mask-RCNN. For each proposal, we describe the relevant details, considering their advantages and disadvantages, as well as the main applications of these methods in various areas. This paper aims to provide a clean and condensed review of the state of the art of these techniques, their usefulness and their implementations in order to facilitate their knowledge and use by any researcher that requires locating objects in digital images. We conclude this work by summarizing the main ideas presented and discussing the future trends of these methods.

A model predictive power system stabilizer is proposed in this paper to damp power oscillations in an electric power system (EPS). The design of the stabilizer is optimal in the sense that its parameters are determined by using off-line particle swarm optimization (PSO) technique. The proposed methodology is applied to an EPS composed by a single machine connected to an infinite bus (SMIB). The analysis is performed through a small signal stability analysis, deriving incremental equations linearized around an operating point. The results obtained by the proposed method are compared with a conventional power system stabilizer, also optimized by PSO. Through numerous computer simulations under different operating conditions and perturbations on the SMIB, it was possible to establish some advantages of the proposed technique as compared with the conventional technique.