Marco Antonio Rodriguez-Blanco

This chapter presents a non-invasive vibration-based method for comparing a baseline with an evaluated condition in a shaft-coupler system. The shaft-speed reference used in the study was not assumed; it was determined from the electrical frequency supplied by the variable-frequency drive and the number of motor poles. For an electrical frequency of 50 Hz and a four-pole motor, the calculated mechanical frequency was 25 Hz, equivalent to 1500 rpm under synchronous conditions. Triaxial signals were acquired and processed under the same operating point, sampling, filtering, and orbital-analysis criteria. The results are technically satisfactory and functional for the comparative objective: S2D = 69.46/100, S3D = 83.86/100, and Sglobal = 73.78/100, classified as a high change relative to baseline. Concurrent changes in R05, R2, R3, SideE, and 2D/3D orbital geometry provide coherent, traceable evidence that clearly differentiates the two tested states. The combined spectral and orbital response is highly compatible with a breathing-crack condition within the experimental scope of the study.

Microcracks in a component are characterized as minor imperfections that manifest in specific materials, particularly those integral to critical structures. Their diminutive size renders detection exceedingly challenging, presenting a substantial obstacle for analysts of structural systems. These microcracks frequently signify the onset of a more extensive degradation process, so they early identification is crucial. Otherwise, the mechanical integrity of the equipment could be put at risk. Currently, standard practice entails subjecting components to laboratory tests, which, although informative, are not invariably nondestructive. Considering this, the adoption of simulations based on modal analysis and the monitoring of stiffness variations under controlled loads is gaining traction, with the objective of shortening evaluation times and safeguarding the component's integrity during diagnosis.

El presente trabajo expone un programa innovador que promueve el buen desempeño en la formación de ingenieros. Este programa establece un sistema de tutoría entre pares, y genera una retroalimentación para mejorar los resultados del aprendizaje cooperativo en disciplinas de ciencias básicas como álgebra avanzada, matemáticas generales, cálculo diferencial e integral. El programa involucra a estudiantes y profesores destacados, quienes, como asesores pares, auxilian a compañeros con dificultades académicas. Para hacer funcionar el sistema propuesto, los coordinadores académicos utilizan formatos digitales para optimizar la capacitación mediante la retroalimentan de datos tanto a los estudiantes como a los asesores. Los resultados de este trabajo brindaron información interesante en donde los alumnos manifestaron su deseo de cambiar su asesor, según su estilo de aprendizaje. Por otro lado, los profesores también compilaron informes sobre las deficiencias que observaron en los estudiantes y sugerencias prácticas para su corrección. Se llevaron a cabo reuniones semanales entre el profesor supervisor a cargo y los asesores pares para evaluar el progreso de los estudiantes, compartiendo estrategias pedagógicas para mejorar la metodología de enseñanza.

Induction motors are the horsepower in the industrial environment, and among them, 3-phase induction motors (3PIMs) stand out for their robustness and standard 3-phase power supply. In the literature, there are many approaches to diagnose faults for the nonlinear 3PIM model, and the vast majority focus on a single motor fault, although others address more faults but at the cost of greater computational complexity. In this sense, one of the methods with less computational load and early detection is the parity equation approach, which is based on analyzing the discrepancy between the input and output signals of a real process and a linear mathematical model to generate a residual signal, which contains important information about the fault and is obtained through a suitable selection of a weighting matrix W to isolate the faults as much as possible. The problem in this case study is that the 3PIM model is a nonlinear system. In this work, the fault detection method based on the parity equations approach applied in the 3PIM is explored using a simplified and proposed model of the 3PIM working in the D-Q synchronous reference frame, which is matched with the direct current motor model to guarantee both the existence of the parity space and to ensure a large set of detectable faults in the 3PIM parameters. Simulation and experimental results validate the proposed scheme and confirm a very simple set of residual equations to guarantee both early detection and a large set of detectable faults in: Stator and rotor resistances, stator and rotor inductances, as well as current, voltage, and speed sensors. Additionally, development of human machine interface (HMI) is implemented to validate the proposed scheme.

In this paper, a complementary and simplified scheme to diagnose electrical faults in a three-phase induction motor using the parity equations approach during steady state operation bases on the stator current reference frame is presented. The proposed scheme allows us to identify the motor phase affected due to faults related to the stator side, such as current sensors, voltage sensors, and resistance. The results obtained in this work complement a detection system that uses the DQ model of the three-phase induction motor and parity equations focused on the synchronous reference frame, which can detect stator-side faults but cannot locate the affected phase. In addition, considering practical and operational aspects, the residual detection set obtained is simplified to three simple algebraic equations that are easy to implement. The simulation results using the PSIM simulation software and the experimental test allow us to validate the proposed scheme.

Video images captured at long range often show low-contrast floating objects of interest on a sea surface. A comparative experimental study of the statistical characteristics of reflections from floating objects and from the agitated sea surface showed differences in the correlation and spectral characteristics of these reflections. The functioning of the recently proposed modified matched subspace detector (MMSD) is based on the separation of the observed data spectrum on two subspaces: relatively low and relatively high frequencies. In the literature, the MMSD performance has been evaluated in general and using only a sea model (i.e., additive Gaussian background clutter). This paper extends the performance evaluating methodology for low contrast object detection using only a real sea dataset. The methodology assumes an object of low contrast if the mean and variance of the object and the surrounding background are the same. The paper assumes that the energy spectrum of the object and the sea are different. The paper investigates a scenario in which an artificially created model of a floating object with specified statistical parameters is placed on the surface of a real sea image. The paper compares the efficiency of the classical matched subspace detector (MSD) and MMSD for detecting low-contrast objects on the sea surface. The article analyzes the dependence of the detection probability at a fixed false alarm probability on the difference between the statistical means and variances of a floating object and the surrounding sea.

This work a novel approach in radio frequency communications applied to a underwater wireless sensors network UWSN is presented. The proposal is to manipulate in a bounded and controlled environment a Remote Operated Vehicle ROV without umbilical cable through a underwater sensors network based on radio frequency communication, taking advantage of the faculties of this underwater communication in conjunction with a sensor network, furter, a dynamic redundancy is used in the transmitters towards the ROV to increasing the range and avoiding communication loss, aditional a static redundancy is applied on the receiver to increase te reliability of comunication. The part of the ROV receiving sensors is based on a statisc redundancy of 3 sensors which will apply a vote taking in order to failure tolerantce, the sensor network will applied a dinamic redundacy in the transmitters in order to follow the communication with the ROV, in case of failure, the communication loss can be compensated with another sensor of the network that will take its role.

In this work, a proton exchange membrane fuel cell (PEMFC) is used to electric energy supply to a permanent magnet DC motor in a sustainable way and the inlet air flow in the cathode is manipulated to ensure the PEM fuel cells efficient operation. A boost-type DC/DC converter is connected to the PEMFC, it is used with a PI linear control loop to regulate the speed of the DC motor under some possible load disturbances. In addition, a nonlinear sliding mode control (SMC) is designed for regulated the excess oxygen ratio considering constant the temperature and humidity of membrane, to achieve the PEM full cell operate in the ohmic region of the polarization curve, to avoid the oxygen starvation at the cathode and to prevent damage to fuel cell components. The results are validated using the internal models of the PEMFC and the power electronics from SimPowerSystems library of Matlab/Simulink.