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241 p. -- Bibliogr.: p. 240-241, En el presente documento se expone el desarrollo de un cliente MQTT que permite realizar comunicaciones seguras mediante TLS, para ser usado en una aplicación que se ejecute sobre un sistema embebido. La aplicación creada también hace uso de otros protocolos TCP/IP, motivo por el cual se han desarrollado clientes adicionales que también son expuestos en este documento. El documento consta de dos partes. La primera parte es la memoria, y en ella se exponen aquellos aspectos teóricos y prácticos de los que es recomendable tener conocimiento para hacer uso del proyecto de programación creado, escrito en lenguaje C y que se encuentra en la segunda parte, de anexos.

Currently, structures are examined during manufacturing by means of Non Destructive Tests (NDT), but there is an increasing interest in monitoring its integrity over its whole life cycle by using Structural Health Monitoring (SHM) strategies. The monitoring of aircraft structures is particularly important as they suffer high strain under extreme atmospheric conditions. There is an extensive literature on SHM for aviation available but there are few references on comprehensive methodologies. This article introduces a methodology, a device and the tests used in its validation. The electronic prototype for structural health monitoring applies ultrasound techniques by means of piezoelectric transducers. It is lightweight, has USB 2.0 connectivity and includes data pre-processing algorithms to improve its performance. It can run in pitch-catch and pulse-echo modes employing passive and active techniques. Passive techniques are used to detect impacts or fiber breakage in composite materials. Tests based on active techniques can bring to light several types of damages such as those caused abruptly or those produced progressively by corrosion, delamination or fatigue.

67 p. -- Bibliogr.: p. 40-41, Este proyecto se trata de un proyecto CBL, un tipo de proyecto que propone implicar directamente a los alumnos y profesores en la optimización del consumo de energía en la Escuela. En este caso, se ha decidido estudiar el diseño de un proyecto de medición en la instalación mediante sensórica, aunque no ha sido el único punto de relevancia del proyecto. El aspecto del ahorro energético en los edificios ha cobrado una mayor importancia este año, debido al elevado precio del gas y electricidad. Es por eso, que urge realizar este proyecto en la escuela, donde una pequeña mejora en la eficiencia del sistema repercute en un gran ahorro monetario. Mediante este proyecto hemos tratado de conocer el grado de eficiencia del sistema de calefacción, midiendo temperaturas de impulsión y también temperaturas del ambiente interior. Para ello hemos usado dos sistemas de medición; un adquisidor de datos comercial y unos arduinos de software libre. El proyecto comenzó tarde, ya que eran mediados de marzo cuando se comienza a trabajar en ello, pero se aprovecharon las últimas semanas de funcionamiento de la calefacción para realizar este estudio. Primeramente, se destinó una semana a estudiar la instalación y conocer su funcionamiento, para posteriormente elegir una zona de la escuela donde realizar las posteriores mediciones. La primera semana de medición, se trató de investigar si las temperaturas que llegan a todas las cotas son iguales, para así poder determinar si la energía térmica disponible en todas las cotas es la misma. En la segunda semana de medición, se trató de medir si dentro de la rama de una cota concreta, el calor se distribuye proporcionalmente o se disipa demasiado en los primeros radiadores. Tras este periodo se analizaron los datos para sacar conclusiones, ya que el funcionamiento de la calefacción se detuvo con la llegada de semana santa, para no volver a funcionar hasta el invierno siguiente. Tras el estudio, se han llegado a varias conclusiones interesantes so

53 p. -- Bibliogr.: p. 48, [ES] El presente trabajo se centra en la realización de una comparativa entre diferentes plataformas para el desarrollo de aplicaciones empotradas. Para ello se he basado en dos plataformas ampliamente conocidas como son por un lado “Raspberry pi” junto con el lenguaje de programación “Python” y por otro lado una placa de desarrollo de un microcontrolador de 32 bits del fabricante “ST Microelectronics” y el lenguaje de programación C/C++. La comparativa se llevará a cabo mediante la implementación de una misma aplicación en ambas plataformas. Las variables más importantes a tener en cuenta en esta comparativa serán las siguientes: el tiempo empleado en la implementación, el coste económico y las capacidades y limitaciones de la plataforma a la hora de desarrollar ciertas aplicaciones. La aplicación escogida ha sido un tablero compuesto por unas luces de reacción para entrenamiento deportivo y cognitivo. Este tipo de entrenamiento es muy utilizado para la mejora de los tiempos de reacción y reflejos de las personas, por ello es conocido que los pilotos de coches de carreras y porteros de fútbol lo incluyen en sus planes de entrenamiento físico. Consiste en un tablero en el que se dispone de unos módulos ubicados a diferentes alturas y posiciones en los que una vez comenzado el juego aleatoriamente se activa uno de ellos, encendiendo su luz correspondiente, y esperará a ser desactivado, ya sea pulsando un pulsador o por medio de un sensor de proximidad. En ese momento el sistema activará un nuevo módulo que realizará la misma operación hasta concluir el juego. La finalización del juego se puede determinar ya sea por un número entero de iteraciones ejecutadas o al cabo de un tiempo transcurrido. Tras el desarrollo de esta aplicación en ambas plataformas se expondrán los datos obtenidos de las variables más importantes previamente mencionadas y se hará una valoración sobre que plataforma es la más adecuada en cada caso dependiendo de los requisitos de desarrollo y produ, [EN] The present work focuses on the realization of a comparison between different platforms for the development of embedded applications. For this purpose, it has been chosen two widely known platforms such as on the one hand Raspberry pi together with the Python programming language and on the other hand a development board of a 32-bit microcontroller from the manufacturer ST Microelectronics, the STM32F769NI-DISC0 and the C/C++ programming language. The comparison will be carried out by implementing the same application on both platforms. The most important variables to take into account in this comparison will be the following: the time spent on the implementation, the economic cost and the capabilities and limitations of the platform when developing the applications. The chosen application has been a board made up of reaction lights designed for sports and cognitive training. This type of training is widely used to improve people's reaction time and reflexes, it is known that racing car drivers and soccer goalkeepers include it in their physical training plans. It consists of a board in which we have some modules located at different heights and positions in which, once the game has started, one of them is randomly activated, turning on its corresponding light, and it will wait to be deactivated, either by pressing a button or by a proximity sensor. At that moment the system will activate a new module that will carry out the same operation until the end of the game. The completion of the game can be determined either by an integer number of executed iterations or after an elapsed time. After the development of this application on both platforms, it will be presented the data obtained from the most important variables previously mentioned and it will be maken an assessment of which platform is the most appropriate in each case depending on the development requirements and the final product.

Damage detection in structural health monitoring of metallic or composite structures depends on several factors, including the sensor technology and the type of defect that is under the spotlight. Commercial devices generally used to obtain these data neither allow for their installation on board nor permit their scalability when several structures or sensors need to be monitored. This paper introduces self-developed equipment designed to create ultrasonic guided waves and a methodology for the detection of progressive damage, such as corrosion damage in aircraft structures, i.e., algorithms for monitoring such damage. To create slowly changing conditions, aluminum- and carbon-reinforced polymer plates were placed together with seawater to speed up the corrosion process. The setup was completed by an array of 10 piezoelectric transducers driven and sensed by a structural health monitoring ultrasonic system, which generated 100 waveforms per test. The hardware was able to pre-process the raw acquisition to minimize the transmitted data. The experiment was conducted over eight weeks. Three different processing stages were followed to extract information on the degree of corrosion: hardware algorithm, pattern matching, and pattern recognition. The proposed methodology allows for the detection of trends in the progressive degradation of structures.

This paper presents a scalable IoT architecture based on the edge–fog–cloud paradigm for monitoring the Indoor Environmental Quality (IEQ) parameters in public buildings. Nowadays, IEQ monitoring systems are becoming important for several reasons: (1) to ensure that temperature and humidity conditions are adequate, improving the comfort and productivity of the occupants; (2) to introduce actions to reduce energy consumption, contributing to achieving the Sustainable Development Goals (SDG); and (3) to guarantee the quality of the air—a key concern due to the COVID-19 worldwide pandemic. Two kinds of nodes compose the proposed architecture; these are the so-called: (1) smart IEQ sensor nodes, responsible for acquiring indoor environmental measures locally, and (2) the IEQ concentrators, responsible for collecting the data from smart sensor nodes distributed along the facilities. The IEQ concentrators are also responsible for configuring the acquisition system locally, logging the acquired local data, analyzing the information, and connecting to cloud applications. The presented architecture has been designed using low-cost open-source hardware and software—specifically, single board computers and microcontrollers such as Raspberry Pis and Arduino boards. WiFi and TCP/IP communication technologies were selected, since they are typically available in corporative buildings, benefiting from already available communication infrastructures. The application layer was implemented with MQTT. A prototype was built and deployed at the Faculty of Engineering of Vitoria-Gasteiz, University of the Basque Country (UPV/EHU), using the existing network infrastructure. This prototype allowed for collecting data within different academic scenarios. Finally, a smart sensor node was designed including low-cost sensors to measure temperature, humidity, eCO2, and VOC.

Nowadays, not only must the structures be in good health when they are manufactured and installed, but also their integrity must be monitored during their life cycle. Nondestructive Test (NDT) techniques are applied in the beginning of the cycle, and Structural Health Monitoring (SHM) techniques afterwards. There is a wide literature on how to monitor integrity in large civil structures, where the size of equipment and accessibility for testing are not serious problems. There are studies that deal about the integrity of airborne vehicles, some focused on the inspection technology or the algorithms used. However, the integrity inspection of an aircraft also requires the development of reliable low volume lightweight electronic equipment with high technical capability. The authors are developing electronic prototypes to satisfy such requirements. The goal of this research is to build an on-board electronic system that monitors the integrity of the airborne structures throughout its lifetime. The prototype uses ultrasound technology with piezoelectric transducers (PZT) and can emit and acquire waveforms on multiple channels simultaneously (pulse-echo or pitchcatch schedules). It can use many test techniques: simple test, beamforming transmission, fast round-robin (associated with beamforming reception), multiple delayed signal, etc. The prototype can generate steerable beams as required. It can also operate in passive mode, i.e. listening to acoustic emissions. The prototype weights 600 g, includes USB 2.0 connectivity, and compresses the data before uploading them to a computer.

The nature of wireless propagation may reduce the QoS of the applications, such that some packages can be delayed or lost. For this reason, the design of wireless control applications must be faced in a holistic way to avoid degrading the performance of the control algorithms. This paper is aimed at improving the reliability of wireless control applications in the event of communication degradation or temporary loss at the wireless links. Two controller levels are used: sophisticated algorithms providing better performance are executed in a central node, whereas local independent controllers, implemented as back-up controllers, are executed next to the process in case of QoS degradation. This work presents a reliable strategy for switching between central and local controllers avoiding that plants may become uncontrolled. For validation purposes, the presented approach was used to control a planar robot. A Fuzzy Logic control algorithm was implemented as a main controller at a high performance computing platform. A back-up controller was implemented on an edge device. This approach avoids the robot becoming uncontrolled in case of communication failure. Although a planar robot was chosen in this work, the presented approach may be extended to other processes. XBee 900 MHz communication technology was selected for control tasks, leaving the 2.4 GHz band for integration with cloud services. Several experiments are presented to analyze the behavior of the control application under different circumstances. The results proved that our approach allows the use of wireless communications, even in critical control applications.

Wireless technologies are being introduced in industrial applications since they provide certain benefits, such as the flexibility to modify the layout of the nodes, improving connectivity with monitoring and decision nodes, adapting to mobile devices and reducing or eliminating cabling. However, companies are still reluctant to use them in time-critical applications, and consequently, more research is needed in order to be massively deployed in industrial environments. This paper goes in this direction by presenting a novel wireless acquisition system aimed at industrial applications. This system embeds a low-cost technology, such as XBee, not frequently considered for deterministic applications, for deploying industrial applications that must fulfill certain QoS requirements. The use of XBee 900 MHz modules allows for the use of the 2.4 GHz band for other purposes, such as connecting to cloud services, without causing interferences with critical applications. The system implements a time-slotted media access (TDMA) approach with a timely transmission scheduling of the messages on top of the XBee 900 MHz technology. The paper discusses the details of the acquisition system, including the topology, the nodes involved, the so-called coordinator node and smart measuring nodes, and the design of the frames. Smart measuring nodes are implemented by an original PCB which were specifically designed and manufactured. This board eases the connection of the sensors to the acquisition system. Experimental tests were carried out to validate the presented wireless acquisition system. Its applicability is shown in an industrial scenario for monitoring the positioning of an aeronautical reconfigurable tooling prototype. Both wired and wireless technologies were used to compare the variables monitored. The results proved that the followed approach may be an alternative for monitoring big machinery in indoor industrial environments, becoming especially suitable for acquiring values

Structural health monitoring comprises a set of techniques to detect defects appearing in structures. One of the most viable techniques is based on the guided ultrasonic wave test (UGWT), which consists of emitting waves throughout the structure, acquiring the emitted waves with various sensors, and processing the waves to detect changes in the structure. The UGWT of layered composite structures is challenging due to the anisotropic wave propagation characteristics of such structures and to the high signal attenuation that the waves experience. Hence, very low amplitude signals that are hard to distinguish from noise are typically recovered. This paper analyzes the propagation of guided waves along a cross-ply composite laminate following an empirical methodology. The research compares several implementations for UGWT with piezoelectric wafer active sensors. The reference for comparison is set on a basic mode, which considers the application of nominal voltage to a single sensor. The attenuation and spreading of the waves in several directions are compared when more energy is applied to the monitored structure. In addition, delayed multiple emission is also considered in multisensor tests. The goal of all the UGWT configurations is to transmit more energy to the structure such that the echoes of the emission are of greater amplitude and they ease the signal processing. The study is focused on the realization of viable monitoring systems for aeronautical composite made structures.

165 p., Esta tesis propone una arquitectura para la medición de dos parámetros que caracterizan elfuncionamiento de un motor aeronáutico: el Tip Clearance y el Time of Arrival. El primero representa ladistancia desde la punta de álabe a la carcasa del motor. El segundo representa el instante en que el álabepasa frente al sensor. Ambos parámetros son el punto de partida para realizar un análisis del estado devibración que sufre ese motor.La arquitectura propuesta para le medida del Tip Clearance y del Time of Arrival consigue podermonitorizar cada álabe de forma individual realizando las medidas en tiempo real. La arquitectura sepuede adaptar a las formas de onda de diversos sensores de los que se emplean habitualmente en estecampo. También permite configurar diversos aspectos de la medida o del ensayo. La arquitectura esescalable y establece un medio de sincronización que permite que se puedan medir simultáneamentevarios sensores instalados en diferentes puntos de la carcasa de motor.La validación de la arquitectura se ha realizado con las formas de onda de un sensor óptico trifurcadoprobado en ensayos reales de una etapa compresora en un túnel de viento. En la implementación se hanpropuesto algoritmos para la determinación de los dos parámetros que se adaptan al procesadoconcurrente y secuencial de una FPGA.

Safety and performance of the turbo-engine in an aircraft is directly affected by the health of its blades. In recent years, several improvements to the sensors have taken place to monitor the blades in a non-intrusive way. The parameters that are usually measured are the distance between the blade tip and the casing, and the passing time at a given point. Simultaneously, several techniques have been developed that allow for the inferencefrom those parameters and under certain conditionsof the amplitude and frequency of the blade vibration. These measurements are carried out on engines set on a rig, before being installed in an airplane. In order to incorporate these methods during the regular operation of the engine, signal processing that allows for the monitoring of those parameters at all times should be developed. This article introduces an architecture, based on a trifurcated optic sensor and a hardware processor, that fulfills this need. The proposed architecture is scalable and allows several sensors to be simultaneously monitored at different points around a bladed disk. Furthermore, the results obtained by the electronic system will be compared with the results obtained by the validation of the optic sensor.Safety and performance of the turbo-engine in an aircraft is directly affected by the health of its blades. In recent years, several improvements to the sensors have taken place to monitor the blades in a non-intrusive way. The parameters that are usually measured are the distance between the blade tip and the casing, and the passing time at a given point. Simultaneously, several techniques have been developed that allow for the inferencefrom those parameters and under certain conditionsof the amplitude and frequency of the blade vibration. These measurements are carried out on engines set on a rig, before being installed in an airplane. In order to incorporate these methods during the regular operation of the engine, signal processing that allows for t

Typical Internet of Things (IoT) applications involve collecting information automatically from diverse geographically-distributed smart sensors and concentrating the information into more powerful computers. The Raspberry Pi platform has become a very interesting choice for IoT applications for several reasons: (1) good computing power/cost ratio; (2) high availability; it has become a de facto hardware standard; and (3) ease of use; it is based on operating systems with a big community of users. In IoT applications, data are frequently carried by means of wireless sensor networks in which energy consumption is a key issue. Energy consumption is especially relevant for smart sensors that are scattered over wide geographical areas and may need to work unattended on batteries for long intervals of time. In this scenario, it is convenient to ease the construction of IoT applications while keeping energy consumption to a minimum at the sensors. This work proposes a possible gateway implementation with specific technologies. It solves the following research question: how to build gateways for IoT applications with Raspberry Pi and low power IQRF communication modules. The following contributions are presented: (1) one architecture for IoT gateways that integrates data from sensor nodes into a higher level application based on low-cost/low-energy technologies; (2) bindings in Java and C that ease the construction of IoT applications; (3) an empirical model that describes the consumption of the communications at the nodes (smart sensors) and allows scaling their batteries; and (4) validation of the proposed energy model at the battery-operated nodes.