Algoritmo de suspensión activa para vehículos ferroviarios

En este proyecto se abordará el desarrollo de un sistema de suspensión activa basado en un nuevo algoritmo, propuesto por el grupo MAQLAB de la Universidad Carlos III de Madrid, que hace uso de la característica determinista del ferrocarril. Para llevarlo a cabo se desarrollará un modelo de vehículo ½ sobre el entorno Simulink/SimMechanics que se validará mediante comparación con otro software de reconocido prestigio. Por otra parte, se planteará el nuevo algoritmo y se implementará en nuestro modelo en Simulink/SimMechanics, obteniendo un vehículo plenamente funcional. Por último, se realizarán simulaciones para comprobar si el funcionamiento del nuevo algoritmo es el esperado y se analizarán los resultados obtenidos. ___________________________________________________________________________________________________This project will address the development of an active suspension system based on a new algorithm, proposed by the MAQLAB group of University Carlos III de Madrid, which uses the deterministic property of railroad. To accomplish this target, a ½ vehicle model must be developed on Simulink/SimMechanics environment and it will be verified by comparison with other renowned software. Moreover, the new algorithm will be explained and, then, installed in our model in Simulink/SimMechanics, obtaining a fully functional vehicle. Finally, some simulations will be conducted to verify if the performance of the new algorithm is that we expected and we will analyze the results.Ingeniería Industria

Metodología para la mejora del diseño de sistemas mecánicos de responsabilidad para el uso de tecnologías avanzadas de mantenimiento DM&M

Mención Internacional en el título de doctorEl ferrocarril es uno de los medios de transporte más utilizados y seguros en la actualidad, jugando un papel muy importante en la movilidad de las personas entre territorios. Además, en los últimos años está experimentando un crecimiento significativo, impulsado por la Alta Velocidad, con trenes capaces de superar los 300 km/h que reducen ostensiblemente la duración de viajes en trayectos de largo recorrido. El mantenimiento del parque ferroviario en un estado de funcionamiento óptimo es prioritario para la operatividad y la seguridad de los servicios. Esto requiere un conocimiento del estado de la vía y de los vehículos ferroviarios, lo cual suele hacerse vía técnicas de auscultación y análisis de parámetros vibratorios. En la presente Tesis Doctoral se ha desarrollado una metodología original encaminada al establecimiento de un procedimiento de diagnóstico del estado de los elementos mecánicos de un sistema ferroviario de alta velocidad mediante el análisis de vibraciones. Esta metodología engloba todos los procesos necesarios para realizar la diagnosis del estado operativo: definición del sistema mecánico analizado, establecimiento de las condiciones de medida, definición del sistema de medida y del sistema de adquisición y registro de datos, acceso y gestión de la base de datos de vibración, selección y consolidación de los datos, tratamiento de los datos mediante técnicas de análisis de señal, en el dominio del tiempo, de la frecuencia y del tiempo-frecuencia y selección de indicadores del estado operativo del sistema. La metodología se aplica a un Tren de Alta Velocidad durante su operación comercial, registrando medidas de las señales de vibración en diferentes condiciones de velocidad, trayecto, tramo y estado operativo. Las medidas vibratorias se han analizado utilizando diversas técnicas de tratamiento de señales en los dominios del tiempo, de la frecuencia y del tiempofrecuencia, algunas tomadas de la literatura técnica y otras originales, desarrolladas expresamente para esta investigación. La interpretación de los resultados obtenidos ha permitido la selección de indicadores del estado operativo del vehículo ferroviario. Para facilitar las tareas de selección y análisis de los datos de vibraciones, se ha concebido una herramienta informática que implementa todas las técnicas de tratamiento de la señal utilizadas. La aplicación software desarrollada dispone de una interfaz gráfica que permite acotar las señales vibratorias a procesar y acceder a todas las técnicas de análisis. Además, permite generar automáticamente informes de los resultados gráficos obtenidos e ir generando un histórico de resultados. Tanto la metodología propuesta como la herramienta software desarrollada tienen un carácter generalista, serían aplicables a cualquier otro sistema mecánico de similares características.Railway is one of the most used and safest modes of transportation today, playing a key role in the mobility of people between territories. In addition, it is undergoing a significant growth driven by High Speed Rail in recent years. High Speed Trains are able to exceed 300 km/h and reduce significantly the duration of travel on long journeys. The maintenance of rolling stock in a good working order is a priority for the operation and safety of the commercial services. This requires the knowledge of the condition of the track and the rail vehicles, which is usually done via auscultation techniques and analysis of vibratory parameters. In this Doctoral Thesis, it has been developed an original methodology aimed at the development of a procedure for diagnosing the state of the mechanical elements of a high-speed rail system through the analysis of vibrations. This methodology encompasses all the processes necessary to perform the operating state diagnosis: definition of the analysed mechanical system, definition of measurement conditions, definition of the measurement system and of the data acquisition and registration system, access and management of the vibration data database, selection and consolidation of data, data processing through signal analysis techniques, in time, frequency and time-frequency domains, and selection of indicators of the operating state of the system. The methodology is applied to a High Speed Train in commercial operation, recording the measurements of the vibration signals in different conditions of speed, path, section and operating state. Vibratory measurements have been analysed using different signal processing techniques in time, frequency and time-frequency domains; some techniques have been taken from the literature and other are original techniques, developed specifically for this research. The interpretation of the obtained results has led to the selection of indicators of the operating state of the railway vehicle. To facilitate the tasks of selection and analysis of vibration data, it has been designed a computer tool that implements all the used signal processing techniques. The developed application software has a graphical interface that allows to set the vibratory signals to process and to access to all the analysis techniques. In addition, it allows to automatically generate reports of the graphic results and to create a history of results. Both the proposed methodology and the developed software tool have a general nature, they would be applicable to any other mechanical system of similar characteristics.Programa Oficial de Doctorado en Ingeniería Mecánica y de Organización IndustrialPresidente: María Luisa Martínez Muneta.- Secretario: Gerardo Peláez Lourido.- Vocal: María Tomás Rodrígue

Modelo paramétrico de la mecánica del robot MIMBOT : aplicación informática MIMBOT 3.5

El presente proyecto está ambientado en el rediseño y evolución del robot bípedo Pasibot, desarrollado por el grupo de investigación MAQLAB, de la Universidad Carlos III de Madrid. El robot Pasibot es un bípedo resultado de la combinación de mecanismos articulados clásicos, de tal forma que el diseño final es capaz de desarrollar la cinemática completa de la pierna humana. El robot Pasibot fue diseñado con menos actuadores que juntas biológicas tiene la pierna humana, disponiendo de un único grado de libertad. Esta condición de diseño restringe grandemente la movilidad del robot por lo que se decidió efectuar un rediseño del mismo, donde añadiéndole grados de libertad al mecanismo base y con el control adecuado, se conseguiría dotar al robot Pasibot de ciertas habilidades. Las nuevas capacidades comprenderían acciones tales como subir un escalón, alargar-acortar el paso, inclinar el pie, superar un pequeño obstáculo, etc. La modificación del diseño del Pasibot consistirá en colocar un par de actuadores lineales en cada uno de los puntos donde el mecanismo inferior de la pierna se fijaba a la cadera. Esta evolución del sistema mecánico del robot Pasibot se plasmaría en un nuevo robot bípedo: el MIMBOT. El objetivo principal de este proyecto fin de carrera es: Diseño de un modelo matemático paramétrico del robot bípedo Mimbot que contemple la variación cinemática y de los centros de masas de los elementos móviles de la pierna del robot y la implementación del modelo en una aplicación gráfica desarrollada con el software Matlab.Ingeniería Técnica en Mecánic

Mathematical analysis of the process forces effect on collet chuck holders

Chuck holders are widely used for jobs with high precision. A chuck holder consists of a nut with a tapered surface and a thin-slotted clamping sleeve typically made of hardened steel and named a collet. Chuck holders are, essentially, wedge mechanisms. In this paper, we investigated the reactions and strains due to the forces during the chip removal process in the contact elements or jaws of the collet by means of mathematical analysis. Deflections in the jaws of the collet arise with a high influence from the precision of the workpieces. The cutting or process forces cause an axial force, a radial force, a torsional moment, and a bending moment on the chuck collet, and, consequently, displacements and inclinations of the clamping system are caused. Therefore, the proposed analytical models are based on elasticity and contact theories. The mathematical model for determining the deflections of the clamping system force was developed and implemented using MATLAB. The results showed that the variation in the clamping force during rotation in a collet chuck holder mainly depends on the stiffness of the collet chuck holder and the stiffness of the workpiece. The results indicated that the collet should be vulcanized to minimize the deformations that affect the final product. The deflections of a collet chuck holder due to process forces depend strongly on the clearances, wedge angle, and stiffness of the collet

Predictive Suspension Algorithm for Land Vehicles over Deterministic Topography

A good suspension system is mandatory for ensuring stability, comfort and safety in land vehicles; therefore, advanced semi and fully active suspension systems have been developed along with their associated management strategies to overcome the limitations of passive suspensions. This paper presents a suspension algorithm for land vehicles traveling through a deterministic topography. The kinematics of a half-vehicle model and the algorithm are implemented in Simulink. The algorithm’s inputs are the measurements provided by a position scanner located on the front wheel of the vehicle. Based on this input, the algorithm reconstructs the topography in real-time and sends the corresponding command to an actuator located on the rear wheel to compensate for the irregularities of the terrain. The actuation is governed by the parameter “D”, which represents the distance over which the algorithm averages the height of the terrain. Two ground profiles were tested and sensitivity analysis of the parameter “D” was performed. Results show that larger values of “D” usually yield less vibration on the actuated mass, but this value also depends on the irregularities of the terrain.The research work described in this paper is part of the R&D and Innovation projects MC4.0 PID2020-116984RB-C21 and MC4.0 PID2020-116984RB-C22 supported by the MCIN/AEI/10.13039/ 501100011033

On the nonlinear hunting stability of a high-speed train bogie

The hunting phenomenon is an intrinsic swaying motion appearing in railway vehicles due to the vehicle's forward speed and the wheel-rail contact forces. Hunting motion consists of wheelset and other vehicle's components oscillations that arise above a certain vehicle's speed known as critical or hunting speed. These oscillations are of unstable nature and represent a safety hazard as they could lead to the vehicle's derailment. This article analyses the stability of a bogie nonlinear model for a Spanish high-speed train when this is travelling at speeds near the hunting speed. The vehicle's stability is studied by means of root loci methods, and the value of the critical speed is found. In addition to this, the behaviour of the vehicle is studied in both stable and unstable regions and the existence of limit cycles is discussed in this work. Finally, a sensitivity analysis of the axle load and suspension parameters is performed. The results show that the axle load, the vertical stiffness of the primary suspension and the lateral damping of the secondary suspension have a significant influence on the value of the critical speed.The research work described in this paper is part of the R&D and Innovation projects MC4.0 PID2020-116984RB-C21 and MC4.0 PID2020-116984RB-C22 supported by the MCIN/AEI/10.13039/501100011033 and by the Universidad Carlos III de Madrid through the "Ayudas para la movilidad de investigadores de la UC3M en centros de investigación nacionales y extranjeros en sus dos modalidades 2019" project

Methodology for the integration of a high-speed train in Maintenance 4.0

The fourth industrial revolution is changing the way industries face their problems, including maintenance. The railway industry is moving to adopt this new industry model. The new trains are designed, manufactured, and maintained following an Industry 4.0 methodology, but most of the current trains in operation were not designed with this technological philosophy, so they must be adapted to it. In this paper, a new methodology for adapting a high-speed train to Industry 4.0 is proposed. That way, a train manufactured before this new paradigm can seize the advantages of Maintenance 4.0. This methodology is based on four stages (physical system, digital twin, information and communication technology infrastructure, and diagnosis) that comprise the required processes to digitalize a railway vehicle and that share information between them. The characteristics that the data acquisition and communication systems must fulfil are described, as well as the original signal processing techniques developed for analysing vibration signals. These techniques allow processing experimental data both in real time and deferred, according to actual maintenance requirements. The methodology is applied to determine the operating condition of a high-speed bogie by combining the signal processing of actual vibration measurements taken during the normal train operation and the data obtained from simulations of the digital twin. The combination of both (experimental data and simulations) allows establishing characteristic indicators that correspond to the normal running of the train and indicators that would correspond to anomalies in the behaviour of the train.The research work described in this paper was supported by the Spanish Government through the MM-IA4.0 PID2020-116984RB-C21 and RMS4.0 PID2020-116984RB-C22 projects

Automatic Expanding Mandrel with Air Sensing Device: Design and Analysis

In precision machining, expanding mandrels are used for jobs with close tolerances. An expanding mandrel consists of a tapered arbor or shaft, with a thin-slotted clamping sleeve or collet made of hardened steel. The internal tapered and external cylindrical surfaces are ground to a high degree of accuracy, and the mandrel expands to fit the internal bore of the workpiece. Expanding mandrels are, essentially, wedge mechanisms. This paper proposes an automatic expanding mandrel with a novel force transmission system for high stiffness within a novel air sensing system, which allows detection of the correct part position before starting machining. A computational model for determining the dynamic clamping force of the proposed mechanism is developed and implemented using MATLAB. This model considers the influence of the sti ness behaviors of the collet, force transmission structure and workpiece. Additionally, this paper presents the finite element method analyses which were conducted to check the proposed computational model. The amount of clamping force transmitted by a collet chuck holder depends strongly on: clearances, wedge angle, stiffness of the collet chuck holder and workpiece stiffness

EMD-Based Methodology for the Identification of a High-Speed Train Running in a Gear Operating State

An efficient maintenance is a key consideration in systems of railway transport, especially in high-speed trains, in order to avoid accidents with catastrophic consequences. In this sense, having a method that allows for the early detection of defects in critical elements, such as the bogie mechanical components, is a crucial for increasing the availability of rolling stock and reducing maintenance costs. The main contribution of this work is the proposal of a methodology that, based on classical signal processing techniques, provides a set of parameters for the fast identification of the operating state of a critical mechanical system. With this methodology, the vibratory behaviour of a very complex mechanical system is characterised, through variable inputs, which will allow for the detection of possible changes in the mechanical elements. This methodology is applied to a real high-speed train in commercial service, with the aim of studying the vibratory behaviour of the train (specifically, the bogie) before and after a maintenance operation. The results obtained with this methodology demonstrated the usefulness of the new procedure and allowed for the disclosure of reductions between 15% and 45% in the spectral power of selected Intrinsic Mode Functions (IMFs) after the maintenance operation.The research work described in this paper was supported by the Spanish Government through the MAQ-STATUS DPI2015-69325-C2-1-R project. Authors would also thank the support provided by the participating companies (Renfe, Alstom Spain, SKF Spain, and Dano-Rail-Danobatgroup Railway) in this project

Enhancement of chromatographic spectral technique applied to a high-speed train

High-speed rail is a key player in people's mobility thanks to its speed and high safety standards. These high safety standards are supported by extensive maintenance (of both rolling stock and track) that applies the latest nondestructive and monitoring techniques. In that context, this work presents the enhanced graphical representation of state configurations (EGRSC) and enhanced chromogram of bands of frequency (ECBF) methods, which are the evolution of the graphical representation of State configurations and chromogram of bands of frequency techniques. A clearer nomenclature is defined for the configuration states of the EGRSC. The ECBF introduces a new variable threshold that allows discarding frequency regions with small power variations and a new color palette. These methods are used in the vibratory study of an in-service high-speed train to identify the operating condition of the train. To conduct that task, a set of accelerometers is installed on the axle box of a trailer axle of the train. Accelerometers are oriented into the three space directions: longitudinal, lateral, and vertical. Vibration signals are taken during the normal operation of the train and transmitted to and stored on a remote database. Vibration measures are collected before and after a major maintenance operation. The application of EGRSC and ECBF allows collecting information from thousands of vibration signals and to display that information intuitively and understandably. The analysis of EGRSC and ECBF results allows identifying several frequency regions with significant spectral power variations that are common to the three vibration directions studied. These patterns should be taken as a reference for future maintenance actions. Any unexpected behavior of these frequency regions would indicate the presence of a fault.The research work described in this paper was supported by the Spanish Government through the MAQ-STATUS DPI2015-69325-C2-1-R project and by the UNED through UNED 2021-MEC-25 project