L’alimentation électrique des trains s’effectue en général par une interface pantographecaténairereprésentant un système mécanique couplé complexe. Les phénomènes dynamiques intervenantdans l’interaction entre le pantographe et la caténaire sont encore mal connus. Par ailleurs, le comportementdynamique du système est très variable car sensible à de nombreux paramètres. La premièrecontribution de cette thèse est de proposer une analyse détaillée de l’interaction dynamique pantographecaténaireen étudiant en particulier la réponse dynamique du pantographe à la géométrie de la caténaireainsi que les propagations, réflexions et transmissions des ondes dans cette dernière. Il a ainsi été démontréque la coïncidence spatiale, temporelle ou fréquentielle de ces différents phénomènes est à l’originede la majorité des variations des quantités d’intérêt. Par ailleurs, l’étude des ondes a montré que lespendules entourant le poteau avaient une importance particulière dans l’interaction dynamique et que lesparamètres tels que le rapport des impédances dynamiques et la somme des vitesses des ondes dans lescâbles étaient des variables dimensionnantes dans la caténaire. La seconde contribution a été de réduireles principales incertitudes épistémiques liées au modèle telles que l’amortissement dans la caténaire, laraideur de contact et la taille des éléments. La dernière contribution était d’implémenter des paramètresvariables dans le modèle en utilisant les mesures disponibles. À partir de ce modèle aléatoire, les incertitudesont été classées en utilisant les indices de Sobol sur des critères géométriques et dynamiques.L’absence de corrélation entre les critères géométriques et dynamique observée a des conséquences notablessur la politique de maintenance. Enfin, le grand nombre d’études de sensibilités réalisés a permisde souligner la maturité de l’outil de simulation et de proposer des orientations pour les travaux futurs pourla conception, maintenance ou homologation de pantographes ou de caténaires / In railways, electrical current is generally collected by the train through a complex coupledmechanical system composed of a pantograph and a catenary. Dynamic phenomena that occur duringtheir interaction are still not fully understood. Furthermore, the system behaviour is sensitive to numerousparameters and thus highly variable. The first contribution of this thesis is a detailed analysis of thepantograph-catenary dynamic interaction separating phenomena due to the dynamic response of the pantographto the catenary geometry from wave propagations, reflections and transmissions that occur in thecatenary. The coincidence of frequencies or characteristic times is then shown to explain most variationsin the quantities of interest. Moreover, droppers surrounding the mast have been shown to be particularlyimportant in dynamic interaction. Ratio of wire impedances and sum of wave velocities also appeared tobe dimensioning quantities for catenary design. The second contribution was to reduce epistemic uncertaintylinked with model parameters such as catenary damping, contact stiffness and element size. Thefinal contribution was to use the model in a configuration with random parameters. An initial step was tostatistically characterise physical catenary parameters using available measurements. From this randommodel, ranking of uncertainties using Sobol indices on static and dynamic criteria was shown to be possible.An absence of correlation between geometric and dynamic criteria was also found, which has notableimplications for maintenance policies. The high number of sensitivity studies also gave the occasion tohighlight the maturity of simulation tool and propose directions for further work on design, maintenance orcertification of pantographs and catenaries.

M.Comm. / Spoornet ( South African Transport Services before 1991) realised since the early 1980's that pressure from its environment would have a serious effect on its economic survival. Since 1991 it has had to fight for its marketshare. Road transport companies started to beat Spoornet on all levels and robbed it of its client base. Spoornet was forced to reform its customer services approach. Pantograph-overheadwire entanglements is one of the obstacles in obtaining customer satisfaction due to the fact that one such incident can cause a train delay of up to three hours. Due the impact this has on the predictability of service, the Chief Engineer (Electrical) set as first objective an entanglement figure of 1 per million pantograph kilometres. A few informal investigations were made into possible technical reasons but none was made into the possible non-technical reasons. As hypothesis it was stated that the efforts of personnel in the organisation to solve the entanglement problem were being handicapped by the lack of motivation, which caused a atmosphere of conflict and frustration. This frustration and conflict has a negative influence on productivity and effectiveness which could be the cause of entanglements. Research done on this was conducted on a dual approach; Literature study as secondary information. Structured interview as primary information. The hypothesis was tested with this study and it was shown that inter-groupconflict, motivation, resource employment and the current approach all had aspects which needed to be addressed to solve the pantograph-overheadwire entanglement problem.

The pantograph - catenary interaction is one of the most important features in high speed trains, and to guarantee a reliable current collection is the target that every railway system must take into consideration in order to speed up trains. The problem that goes against this direction is mainly the variation of the overhead equipment's stiness. To understand the phenomenon a lumped mass model of the pantograph with a rigid body attached to the ground representing the contact wire were built up; in this way a complete lumped mass model is developed. All information regarding both wire and pantograph set up is introduced as lumped parameters. Creating the model, dierent active control strategies as ideal control, PID control and optimal control are introduced. All simulations are made in GENSYS, while the control part is made inSIMULINK; a connection between those two softwares was created as part of the thesis using TCP/IP protocol. Results compared to experimental acquisition are satisfactory in terms of contact force representation. The standard deviation and average value's errors of the contact force are lower than 10%; regarding the control system, typically 20% of reduction of the standard deviation compared to the passive case is achieved. Also a comparison with a nite element program is done in order to better understand the limits of the model compared with a more sophisticated one. The comparison shows a good accordance up to 60 % of the average speed of the wave propagation in the catenary. The last feature analyzed is how the behavior of the controlled system changes introducing a real actuator: results shows that the performance is reduced in dierent ways considering dierent speeds, but no instabilities occur.

Exoskeletons are getting popular day by day due to their abilities in helping people. Exoskeletons can be used to help people gain motor senses through rehabilitation. It can also help healthy people to augment their abilities. These exoskeletons need to be strong yet light, so that the human body can support the exoskeleton, while the exoskeleton can support the activity that is being performed. This calls for under-actuated systems, which help in avoiding unnecessary mass due to additional actuators, while providing the same movement capabilities. This thesis describes in detail about two such under-actuated upper body exoskeletons which can be used for lifting loads. The design of such exoskeletons and novel control techniques for comfortable usage is discussed in detail. / Master of Science / Exoskeletons are assistive devices which can help people in several ways. An exoskeleton can help people who are affected with stroke by enabling them to walk through rehabilitation and physiotherapy. It can also help people to perform beyond their capacity in terms of physical activities. This could be to lift more load than possible, run faster than usual. This thesis describes the design and working two such exoskeletons which can be attached to the upper body. These exoskeletons can be used by people to lift loads which would require a lot of effort and muscle activity. The addition of these exoskeletons potentially reduce the muscle activity on the user and helps avoiding injuries in long term. Such exoskeletons have to be light weight so that they do not defeat the purpose of reducing muscle activity. This problem is solved by using under-actuated systems, because a significant mass of the exoskeleton is taken by the actuators such as the motors. Using under-actuated systems help in lowering the mass of the exoskeleton, while still being able to perform the same kinds of motion. This thesis also talks about how these exoskeletons can be controlled such that the load is being lifted with minimal efforts, and being aware of the loads it is lifting to provide the correct amount of torque, above or below which can lead to the motor shooting up or down causing muscular discomfort and injuries in the arm.

Tesis por compendio / [ES] Existe una extensa red de líneas ferroviarias electrificadas en todo el mundo. La mayoría de ellas utilizan líneas aéreas de contacto o catenarias para suministrar electricidad a los trenes. Las catenarias son estructuras de cables ubicadas sobre las vías ferroviarias, diseñadas para ser contactadas por los pantógrafos que se encuentran sobre la parte superior de los trenes. El correcto funcionamiento del sistema requiere un alto nivel de exigencia, especialmente a alta velocidad, cuando la continuidad del contacto se ve comprometida. La herramienta más empleada el sistema pantógrafo-catenaria es el uso de simulaciones numéricas. En particular, el Método de los Elementos Finitos (MEF) es la técnica más extendida para modelar y simular la interacción dinámica del pantógrafo con la catenaria. Después de la etapa de simulación, el pantógrafo y la catenaria tienen que ser testados mediante ensayos experimentales en vía. Sin embargo, existe una alternativa que puede reemplazar esos ensayos con una reducción significativa de costes. Dicha alternativa, llamada Hardware In the Loop (HIL), permite testar pantógrafos en el laboratorio mediante un banco de ensayos que emula la interacción con una catenaria virtual. Diferentes grupos de investigación han implementado HIL; sin embargo, en todos los intentos se han adoptado soluciones de compromiso, lo que demuestra el reto que supone la aplicación de HIL. Esta Tesis pretende avanzar en el campo de ensayos HIL, impulsando las capacidades de la técnica y solventando algunas de las limitaciones encontradas en la literatura. Para ello se proponen dos tipos diferentes de modelos de catenaria para su uso en ensayos HIL. El primero es un modelo analítico basado en un cable tensado con perfil geométrico periódico que proporciona la solución estacionaria del sistema. Este enfoque reduce la complejidad de la catenaria, pero mantiene las principales características que intervienen en la dinámica. El modelo ha demostrado ser útil para explicar el comportamiento fundamental de la catenaria, ayudando a comprender el fenómeno de interferencia entre dos pantógrafos. Este modelo analítico es adecuado para HIL debido a su bajo coste computacional. En el presente trabajo se propone un algoritmo iterativo para utilizar el modelo analítico en HIL. El hecho de que el modelo sea periódico permite la aplicación de una estrategia específica para compensar el retraso del lazo de control. Esta estrategia tiene un excelente rendimiento y precisión, validados al comparar ensayos HIL con simulaciones. La validación se realiza con un peso en el lugar del pantógrafo para eliminar las potenciales diferencias en el modelo. Si bien la precisión alcanzada es buena, el modelo analítico de catenaria carece de fidelidad, lo que ha motivado el desarrollo del siguiente modelo. El segundo modelo de catenaria para ensayos HIL es el Modelo Periódico de Elementos Finitos (MPEF), discretizado con el MEF para evitar adicionales simplificaciones topológicas y estructurales. En la formulación se incluye la condición de periodicidad y la dinámica se resuelve mediante análisis en frecuencia. Además, las no linealidades de la catenaria se consideran en la formulación. Un algoritmo iterativo, similar al utilizado para los ensayos HIL con catenaria analítica, es usado para realizar ensayos HIL con catenarias MPEF. La estrategia anterior de utilización de un peso se emplea para validar el sistema de ensayos, resultando tener una gran precisión. Los resultados son gratificantes debido a la sofisticación del modelo de catenaria, la precisión de los ensayos y la cancelación del retraso. Los ensayos realizados simulan la respuesta de catenarias realistas con la hipótesis simplificativa de periodicidad. Son adecuados para la dinámica de catenarias de vanos iguales en la zona central de cada cantón, sin embargo es necesario seguir realizando esfuerzos para eliminar la condición de periodicidad sin comprometer la precisión de los resultados. / [CA] Existeix una extensa xarxa de línies ferroviàries electrificades a tot el món. La majoria d'elles utilitzen Línies Aèries de Contacte o catenàries per a subministrar electricitat als trens. Les catenàries són estructures de cables situades sobre les vies ferroviàries, dissenyades per a ser contactades pels pantògrafs que es troben sobre la part superior de la locomotora. El correcte funcionament del sistema requereix un alt nivell d'exigència, especialment a alta velocitat, quan la continuïtat del contacte es veu compromesa. L'eina majoritària per el sistema pantògraf-catenària és l'ús de simulacions numèriques. En particular, el Mètode dels Elements Finits (MEF) és la tècnica més usada per a modelar i simular la interacció dinàmica del pantògraf amb la catenària. Aquest mètode permet modelar catenàries. Després de l'etapa de simulació, el pantògraf i les catenàries han de ser testats en assajos experimentals en via. No obstant això, existeix una alternativa que pot reemplaçar eixos assajos amb una reducció significativa de costos. Aquesta alternativa, anomenada Hardware in the Loop (HIL), permet testar pantògrafs en el laboratori amb un banc d'assajos que emula la interacció amb una catenària virtual. Diferents grups d'investigació han implementat HIL; no obstant això, en tots els intents s'han adoptat solucions de compromís, la qual cosa demostra el repte que suposa l'aplicació de HIL. Aquesta Tesi pretén avançar en el camp dels assajos HIL, impulsant les capacitats de la tècnica i solucionant algunes de les limitacions trobades en la literatura. Aquesta Tesi proposa dos tipus diferents de models de catenària per al seu ús en assajos HIL. El primer és un model analític basat en un cable tens amb perfil geomètric periòdic que proporciona la solució estacionària del sistema. Aquest model redueix la complexitat de la catenària, però manté les principals característiques que intervenen en la dinàmica. El model ha demostrat ser útil per a explicar la dinàmica fonamental de la catenària, ajudant a comprendre el fenomen d'interferència entre dos pantògrafs. Aquest model analític és adequat per a realitzar assajos HIL a causa del seu baix cost computacional. Aquest treball proposa un algoritme iteratiu per a utilitzar el model analític en assajos HIL de pantògrafs. El fet que el model siga periòdic permet l'aplicació d'una estratègia específica per a compensar el retard del llaç de control. Aquesta estratègia té un excel·lent rendiment i precisió, validats en comparar assajos HIL amb simulacions numèriques. La validació es realitza amb una massa en el lloc del pantògraf per a eliminar les potencials diferències en el model. Si bé la precisió aconseguida és bona, el model analític de catenària manca de fidelitat, la qual cosa ha motivat el desenvolupament d'un model periòdic més avançat. El segon model de catenària per a assajos HIL és el Model Periòdic d'Elements Finits MPEF, discretitzat amb el MEF per a evitar simplificacions topològiques i estructurals addicionals. El model inclou la condició de periodicitat i la dinàmica es resol mitjançant anàlisi en freqüència. A més, les no linealitats de la catenària es consideren en la formulació. Un algoritme iteratiu, similar a l'utilitzat per als assajos HIL amb catenària analítica, és usat per a realitzar assajos HIL amb catenàries MPEF. L'estratègia anterior d'utilització d'una massa s'empra per a validar el sistema d'assajos, resultant tindre una gran precisió. Els resultats són gratificants a causa de la sofisticació del model de catenària, la precisió dels assajos i la cancel·lació del retard. Els assajos realitzats simulen la resposta de catenàries realistes amb la hipòtesi simplificativa de periodicitat. Són adequats per a la dinàmica de catenàries de vans iguals en la zona central dels seccionaments, no obstant això és necessari continuar fent esforços per a eliminar la condició de periodicitat sense comprometre la precisió dels res / [EN] There is an extensive network of electrified railway lines over the world. Most of them use overhead contact lines or catenaries to provide the trains with electrical power. Catenaries consist of electrified wires placed over the rail track, designed to contact the pantograph placed on the roof of the train. The proper operation of the system is very demanding, especially at high speed, when the continuity of the contact is compromised. The most predominant tool for studying and designing the pantograph-catenary system is the use of numerical simulations. Notably, the Finite Element Method (FEM) is the most popular technique for modelling and simulating the dynamic interaction of the pantograph and the catenary. This method allows modelling catenaries with outstanding fidelity and without any loss of generality. After the simulation stage, the pantograph and the catenaries have to be assessed by in-line experimental tests. However, there is an alternative that can replace those tests with a significant reduction in costs. The alternative method, called Hardware In the Loop (HIL), allows testing pantographs in the laboratory with a test rig that emulates the interaction with a virtual catenary. Different research groups have implemented HIL; however, in every attempt, a compromise solution has been adopted, demonstrating the challenging nature of HIL. This Thesis aims to advance in the field of HIL tests, pushing forward the capabilities of the technique and solving some of the limitations found in the literature. This Thesis proposes two different kinds of catenary models for their use in HIL tests. The first is an analytical model based on a string of periodic geometric profile that accounts for the steady state. It reduces the complexity of the catenary but keeps the main features involved in the dynamic. The model has proven useful in explaining the fundamental dynamics of the catenary, helping understand the interference between two pantographs. This analytical model is suitable for HIL because of its low computational cost. An iterative algorithm is proposed to use the analytical model in HIL. The fact that the model is periodic permits a specific strategy to compensate the control loop delay. This strategy has excellent performance and accuracy, validated by comparing HIL tests with numerical simulations and getting an agreement. This agreement will not be possible if the pantograph model of the simulations is inaccurate. Therefore, the validation is carried out with a weight or mass model in place of the pantograph to eliminate potential differences. Even though the precision achieved is good, the analytical catenary model lacks fidelity, which has motivated the development of a more advanced periodic model. The second catenary model for HIL tests is the Periodic Finite Element Model (PFEM), discretised with FEM to avoid further topological and structural simplifications. The model includes the periodicity condition, and the dynamics are solved by frequency analysis. Furthermore, the catenary non-linearities are considered in the formulation. An iterative algorithm, similar to the one used for the HIL tests with the analytical catenary, is used to realise HIL tests with PFEM catenaries. The previous strategy with a mass model is used to validate the test, confirming great precision. The results are gratifying due to the sophistication of the model, the accuracy of the tests and the cancellation of the delay. The tests simulate the response of realistic catenaries with the simplifying periodicity hypothesis. They are adequate for the dynamic of equal-span catenary at the central zone of every section, but future efforts have to be made to get rid of the periodicity condition while keeping the accuracy of the results. / The authors would like to acknowledge the financial support received from the State Research Agency of the Spanish Science and Innovation Ministry (PID2020- 113458RB-I00) and from the Valencian Regional Government (PROMETEO/2021/046) (PROMETEO/2016/007) and the Spanish Ministry of Economy, Industry and Competitiveness (TRA2017-84736-R), also the funds received jointly from the Regional Government of Valencia and the Euro- pean Social Fund, under Grant APOSTD/2019/205 / Gil Romero, J. (2022). Pantograph-Catenary Dynamic Models and their Implementation in Hardware-in-the-Loop Tests [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/191501 / Compendio

O estado do Rio Grande do Sul possui as maiores jazidas de ágata de que se tem conhecimento. Este material gemológico é utilizado para uma gama abrangente de aplicações em joalheria e produtos e neste formato pode elevar significativamente o seu valor de mercado. Cerca de 80% da produção de ágata é destinada à exportação, principalmente para a China e a Alemanha. O centro de beneficiamento de ágata no Brasil, que detém a maior concentração de empresas, está localizado na região de Soledade, no Rio Grande do Sul. Este município é conhecido mundialmente como polo industrial de “pedras preciosas”. Porém as tecnologias de beneficiamento de ágata das indústrias locais são bastante limitadas e com pouca inovação, sendo que o trabalho tem maior foco na comercialização direta, ou seja, em bruto, e em alguns produtos manufaturados de baixa complexidade tecnológica. Esta pesquisa trata da produção de camafeus, que são pequenas esculturas feitas normalmente em ágata e que são utilizadas na forma de broches e adornos, que em composição com ouro e prata podem se transformar em produtos de joalheria. Para tal, é proposto o desenvolvimento de um protótipo de equipamento para a confecção de camafeus, por um sistema de cópia, sendo uma adaptação de uma fresadora pantográfica. Esse protótipo foi projetado para ser utilizado pelos pequenos produtores soledadenses, que contabilizam cerca de 150 empresas cadastradas na APPESOL (Associação dos Pequenos Pedristas de Soledade). A proposta é de uma alternativa técnica de baixo custo para a criação de produtos de alto valor agregado e a inserção de esculturas em ágata feitas no Brasil no mercado interno e externo. A copiadora de camafeus faz uso de ferramentas diamantadas e copia um modelo produzido em outro material. Ensaios iniciais apontam que camafeus em ágata podem ser executados com esta técnica, porém há a possibilidade de inúmeros materiais gemológicos serem beneficiados também. / The state of Rio Grande do Sul has the biggest agate deposits, this gemological material is used for a wide range of applications in jewelry and products, increasing significantly its value on the market. About 80% of agate production is exported mainly to China and Germany. The agate processing center in Brazil which holds the largest concentration of companies is located in Soledade, Rio Grande do Sul. This municipality is known worldwide as the gems industrial center. However, the processing technology of the local companies are quite limited, with little innovation, whereas being focused on the direct marketing, in other words, in the raw state, and in some manufactured products with low technological complexity. This research is about the cameo production, which are small sculptures usually made of agate and used in the form of brooches and ornaments, that in composition with gold and silver turn into jewels. In order to achieve this is through the development of an mechanism prototype to produce the cameos, using a copying system by adapting a pantograph milling machine. This prototype was designed to be used by small producers which account for 150 companies registered at APPESOL (Small Gems Producers Association of Soledade). The proposal is a low – cost alternative technique for creating products and insertion of agate sculptures produced in Brazil’s national and international markets. The cameo copy machine makes use of diamond tools, that copies from a model made of different material. Initial tests show that agate cameos can be produced using this technique and other gemological materials can use this technique as well.

Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 1980. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND ENGINEERING. / Includes bibliographical references. / by Li-Moon Wann. / M.S.

Der Kontakt Fahrdraht - Schleifleiste hat die Aufgabe, elektrischen Strom zwischen der Oberleitung und dem Stromabnehmer des Triebfahrzeuges mittels eines Gleitkontaktes zu übertragen. Das Kontaktverhalten und der dabei entstehende Verschleiß sind von einer Vielzahl von Parametern und Einflussfaktoren sowie deren Verknüpfungen abhängig. Der Verschleiß lässt sich in elektrischen und mechanischen Verschleiß unterteilen. Die vorliegende Arbeit beschreibt erstmals zusammenhängend und umfassend das Kontakt- und Verschleißverhalten von Fahrdraht und Schleifleiste. Daraus geht hervor, dass der Kontaktwiderstand eine herausragende Bedeutung für den elektrischen Verschleiß besitzt. Zur Berechnung des Kontaktwiderstandes existieren für einen stationären Kontakt mehrere Modelle, die jedoch auf einer Vielzahl von Annahmen und Vereinfachungen beruhen. Die Messung des Kontaktwiderstandes zwischen dem Fahrdraht und der Schleifleiste ist somit zwingend erforderlich. Dafür wurde an der TU Dresden ein Versuchsstand errichtet, mit dem der Kontaktwiderstand unter möglichst realen Bedingungen gemessen werden kann. Untersucht wurde die Kontaktpaarung Kupferfahrdraht und Kohlenstoffschleifleiste. Die durchgeführten Messungen des Kontaktwiderstandes und der Temperaturen von Fahrdraht und Schleifleiste im Stillstand und bei Fahrt werden beschrieben und ausgewertet. Dabei zeigt sich, dass die Kontaktkraft und der Kontaktstrom den größten Einfluss auf den Kontaktwiderstand besitzen. Der Kontaktwiderstand bzw. die Kontaktspannung bilden die Grundlage zur Berechnung der Erwärmung des Kontaktbereiches. Es wird ein Verfahren vorgestellt, mit welchem die maximalen Temperaturen in Fahrdraht und Schleifleiste ermittelt werden können. Die auf diese Weise ermittelten Temperaturen erlauben tendenzielle Aussagen zum elektrischen Verschleiß.

Thesis (M.S.)--University of Michigan, 1985.

Thesis (M.S.)--University of Michigan, 1975.