Lagrangian Model‐Based Fault Diagnosis in a PVTOL

A Lagrangian formalism is used to model a PVTOL in order to obtain an aircraft model. The Euler‐Lagrange model of the PVTOL is used to develop an algorithm for fault diagnosis. Diagnosis implies the detection, isolation and identification of a fault. The considered approach is based on the knowledge of a system model as well as the model of the possible faults. The idea is to use non‐linear decoupling approach to derivate a set of subsystems, each related to a specific fault or a set of faults. An observer‐based residual generation is designed for each subsystem, this structure allows the fault detection and isolation stage, for fault identification a kind of approximated inversion algorithm to meet the different diagnostic levels. The results are obtained taking advantage of the structure given by the Euler‐Lagrange modelling of the PVTOL as well as from recent results related to observer design and fault identification

Respuesta en frecuencia para sistemas en espacio de estados

The frequency response of linear systems is a popular tool used in the analysis and design of automatic control systems. The common way to obtain the frequency response is from the input-output representation (transfer function) of a system. In this paper we present a novel way to obtain the frequency response from the state space representation. The result is obtained by characterizing the input signal (sine function) by means of an additional external system, as well as the evaluation of the steady state. The determination of phase and magnitude is obtained from the solution to a Sylvester equation repeatedly for different values of the frequency in a specific interval together with some algebraic manipulations and use of trigonometric identities. The procedure is shown by examples and compared with classical ways of obtaining the frequency response.La respuesta en frecuencia de sistemas lineales es una popular herramienta utilizada en el análisis y diseño de sistemas de control automático. La forma común de obtener la respuesta en frecuencia es a partir de la representación entrada-salida (función de transferencia) de un sistema. En este trabajo se presenta una manera novedosa para obtener la respuesta en frecuencia partiendo de la representación en el espacio de estados. El resultado es obtenido mediante la caracterización de la señal de entrada (función senoidal) mediante un sistema externo adicional, así como la evaluación del estado estacionario. La determinación de la fase y magnitud se obtiene de la solución a una ecuación de Sylvester reiteradamente para diferentes valores de la frecuencia en un intervalo específico junto con algunas manipulaciones algebraicas y uso de identidades trigonométricas. El procedimiento es mostrado mediante ejemplos y comparado con las maneras clásicas de obtener la respuesta en frecuencia

Clonal chromosomal mosaicism and loss of chromosome Y in elderly men increase vulnerability for SARS-CoV-2

The pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2, COVID-19) had an estimated overall case fatality ratio of 1.38% (pre-vaccination), being 53% higher in males and increasing exponentially with age. Among 9578 individuals diagnosed with COVID-19 in the SCOURGE study, we found 133 cases (1.42%) with detectable clonal mosaicism for chromosome alterations (mCA) and 226 males (5.08%) with acquired loss of chromosome Y (LOY). Individuals with clonal mosaic events (mCA and/or LOY) showed a 54% increase in the risk of COVID-19 lethality. LOY is associated with transcriptomic biomarkers of immune dysfunction, pro-coagulation activity and cardiovascular risk. Interferon-induced genes involved in the initial immune response to SARS-CoV-2 are also down-regulated in LOY. Thus, mCA and LOY underlie at least part of the sex-biased severity and mortality of COVID-19 in aging patients. Given its potential therapeutic and prognostic relevance, evaluation of clonal mosaicism should be implemented as biomarker of COVID-19 severity in elderly people. Among 9578 individuals diagnosed with COVID-19 in the SCOURGE study, individuals with clonal mosaic events (clonal mosaicism for chromosome alterations and/or loss of chromosome Y) showed an increased risk of COVID-19 lethality

Control activo tolerante a fallas para sistemas hamiltonianos convergentes.

En este trabajo se presenta una propuesta para resolver el problema de diagnóstico y control activo tolerante a fallas para una clase de sistemas convergentes que admiten una representación Hamiltoniana. La propuesta consiste en un nuevo enfoque para hacer la detección y aislamiento de fallas así como una nueva estructura de control activo tolerante a fallas. El enfoque de diagnóstico se realiza con métodos basados en el modelo específicamente usando observadores no lineales, con los observadores se forman los generadores de residuo a partir de los cuales se define la ocurrencia de fallas, se propone una forma de diseño para los observadores no lineales a partir de la representación Hamiltoniana generalizada; con los observadores no lineales se forman los generadores de residuo con los cuales se detecta la ocurrencia de fallas y para el aislamiento de fallas se aplica una metodología de desacoplo con la que se obtienen subsistemas con sensibilidad a alguna falla. La estructura propuesta de control activo tolerante a fallas permite eliminar el efecto de la falla, una de sus características es que para la reconfiguración no es necesario modificar la ley de control nominal lo cual puede llegar a ser de gran utilidad cuando se quiera implementar éste enfoque de tolerancia a un sistema de control, con esta estructura se pretende hacer que la trayectoria del sistema con falla siga a la trayectoria del sistema nominal para de esta manera recuperar el desempeño nominal, recuperación de desempeño nominal se refiere a que la salidav del sistema con falla al ser reconfigurado alcance nuevamente el valor de la referencia, ésto siempre y cuando las condiciones físicas del sistema en presencia de falla lo permitan. Para mostrar la eficiencia del enfoque propuesto de diagnóstico éste se aplica en simulación a un Motor Síncrono de Imán Permanente (PMSM por sus siglas en inglés) y a un PVTOL (Planar Vertical Take Off and Landing aircraft). De igual forma se aplica en simulación la estructura propuesta de control activo tolerante a fallas al PMSM

Localización de fallas en un aerogenerador vía redundancia analítica

La localización de fallas basada en modelos es considerada en un aerogenerador utilizado como banco de pruebas. La localización de fallas en los generadores eólicos es una tarea muy importante para mejorar la calidad de la energía (incluyendo estrategias de reconfiguración del sistema) así como para permitir el mantenimiento adecuado. En este trabajo se considera el uso de técnicas de diagnóstico basadas en observadores para la localización de fallas en el generador eólico. La propuesta es probada con una simulación realista proporcionada por un fabricante de generadores eólicos

Prony Method Estimation as a New Approach for Surge Comparison Testing in Turn Insulation Diagnostics for Three Phase Stator Windings

This article presents an evaluation of Prony method estimation and its implementation considerations for surge comparison test application in turn insulation diagnostics for three-phase stator windings. Surge testing diagnostics compares recorded surge voltage signals of motor winding, and a diagnostic is then defined with a defined value of EAR (error area ratio), which evaluates the difference between signals to determine a turn insulation diagnostic. First, an overview of surge testing is presented. Next, the Prony method and the considerations for its implementation in surge testing are described. Then, a numerical simulation is used to define a simulated turn fault surge voltage signal, where its parameters can be obtained with Prony method estimation and compared with EAR to evaluate its performance. Lastly, recorded surge test signals from two tested motors are used to validate Prony method estimation application for surge test diagnostics, where twelve recorded surge signals for no-fault and fault conditions were analyzed. The summary results of the surge signals parameter estimation are presented in the results and discussion section

Prony Method Estimation as a New Approach for Surge Comparison Testing in Turn Insulation Diagnostics for Three Phase Stator Windings

This article presents an evaluation of Prony method estimation and its implementation considerations for surge comparison test application in turn insulation diagnostics for three-phase stator windings. Surge testing diagnostics compares recorded surge voltage signals of motor winding, and a diagnostic is then defined with a defined value of EAR (error area ratio), which evaluates the difference between signals to determine a turn insulation diagnostic. First, an overview of surge testing is presented. Next, the Prony method and the considerations for its implementation in surge testing are described. Then, a numerical simulation is used to define a simulated turn fault surge voltage signal, where its parameters can be obtained with Prony method estimation and compared with EAR to evaluate its performance. Lastly, recorded surge test signals from two tested motors are used to validate Prony method estimation application for surge test diagnostics, where twelve recorded surge signals for no-fault and fault conditions were analyzed. The summary results of the surge signals parameter estimation are presented in the results and discussion section

Design Implication of a Distribution Transformer in Solar Power Plants Based on Its Harmonic Profile

This article presents a comparative analysis for the design considerations for a solar power generation transformer. One of the main existing problems in transformer manufacturing is in the renewable energy field, specifically the solar power generation, where the transformer connected to the inverter is operated under a certain harmonic content and operating conditions. The operating conditions of the transformer connected to the inverter are particularly unknown for each solar power plant; thus, the transformer will be subject to a particular harmonic content, which is defined by the inverter of the solar power plant. First, the fundamental calculations for solar power plant transformer and the proposed methodology for the design calculation of the distribution pad-mounted three phase transformer are presented. Then, a design study case is described where a distribution transformer and an inverter of a particular solar power plant are used for the analysis. Next, the transformer under analysis is modeled using finite element analysis in ANSYS Maxwell® software, where the transformer will be designed for a non-harmonic and harmonic content application. Lastly, the main design parameters, flux density, the core losses and the winding excitation voltage of the transformer are calculated and presented in results and discussion section

Prony Method Estimation for Motor Current Signal Analysis Diagnostics in Rotor Cage Induction Motors

This article presents an evaluation of Prony method and its implementation considerations for motor current signal analysis diagnostics in rotor cage induction motors. The broken rotor bar fault signature in current signals is evaluated using Prony method, where its advantages in comparison with fast Fourier transform are presented. The broken rotor bar fault signature could occur during the life cycle operation of induction motors, so that is why an effective early detection estimation technique of this fault could prevent an insulation failure or heavy damage, leaving the motor out of service. First, an overview of cage winding defects in rotor cage induction motors is presented. Next, Prony method and its considerations for the implementation in current signature analysis are described. Then, the performance of Prony method using numerical simulations is evaluated. Lastly, an assessment of Prony method as a tool for current signal analysis diagnostics is performed using a laboratory test system where real signals of an induction motor with broken rotor bar operated with/without a variable frequency drive are analyzed. The summary results of the estimation (amplitudes and frequencies) are presented in the results and discussion section

Caracterización técnica-productiva de los sistemas ganaderos del sur del estado Anzoátegui. Manejo del recurso pastizal

With the purpose of characterizing the cattle systems in southern Anzoátegui state, an evaluation of the technical-productive indicators was done in 70 cattle farms selected at random and located in a radius of 50 km from the Centre for Agricultural Research of the Anzoátegui state. The data were collected by means of a fast survey applied to the owners of the farms, referred to pasture management, animal population, infrastructure and equipment, feeding handling, and fate of the production. The statistical analysis was descriptive. Cattle farms are oriented to the double intention (47.5%), with paddocks of variable size, being the average 28.3 ha, where the continuous grazing prevailed (81.4%). The average of the area with introduced pasture was 178.8 ha. The utilization values of the grass for ha/cow-mass and unit cow-mass/ha were 21.9 and 0.3, respectively for the area with introduced grass. The cattle farms in southern Anzoátegui state were characterized for being extensive with great areas of native grass and with low technique-productive investment.Con la finalidad de caracterizar los sistemas ganaderos al sur del estado Anzoátegui, se realizó una evaluación de los indicadores técnicos-productivos a 70 fincas ganaderas seleccionadas al azar y ubicadas en un radio de 50 km de la sede del Centro de Investigaciones Agrícolas del estado Anzoátegui. Los datos fueron obtenidos mediante una encuesta rápida aplicada a los propietarios de las fincas referida al recurso pastizal, población animal, infraestructura y equipo, manejo de la alimentación y destino de la producción. El análisis estadístico fue descriptivo. Las fincas están orientadas al doble propósito (47,5%), con potreros de tamaño variables, siendo el promedio 28,3 ha, donde prevalece el pastoreo continuo (81,4%). El promedio de la superficie con pastura introducidas es de 178,8 ha. Los valores de utilización del pasto, tanto ha/vaca-masa como unidad vaca-masa/ha, fueron 21,9 y 0,3, respectivamente, para la superficie con pasto introducido. Las explotaciones ganaderas al sur del estado Anzoátegui se caracterizaron por ser extensivas, con grandes áreas de pasto nativo y con poca inversión técnica-productiva