El sector del transporte y la movilidad está experimentando profundas transformaciones debidas principalmente a la concienciación medioambiental, al aumento de la población de las grandes áreas urbanas y al tamaño de las ciudades, al envejecimiento de la población y la aparición de relevantes innovaciones tecnológicas que han cambiado los hábitos de consumo, como el comercio electrónico o la economía colaborativa. Así, el auge de aplicaciones móviles como Uber y Cabify están transformando la movilidad urbana y metropolitana que debe adaptarse a este nuevo escenario y al propio concepto de movilidad. Estas aplicaciones ofrecen una alternativa a las prestaciones que tradicionalmente ha brindado el sector del taxi y el alquiler de vehículos con conductor (VTC), y se han desarrollado en un contexto de regulación de los mercados del taxi y VTC que contienen importantes restricciones no justificadas a la entrada y ejercicio de la actividad en el mercado, entre las que destaca el numerus clausus de licencias, el limitado ámbito geográfico de la licencia y, para el caso del taxi, los precios regulados en forma de tarifas públicas no flexibles. En este estudio, y aprovechando los últimos cambios legislativos que afectan sobre todo a la prestación de servicios de estas plataformas en España, se ha analizado cómo ha impactado su implantación en la seguridad vial de Madrid en dos periodos temporales diferenciados (2014-2018 y 2013-2019). En primer lugar, se ha analizado cómo ha afectado la entrada de estos servicios en la frecuencia de los accidentes -con al menos un herido grave o muerto-, diferenciando entre accidentes con presencia de alcohol o drogas y accidentes producidos en fin de semana y festivo. En segundo lugar, y teniendo en cuenta que por cada muerte en las carreteras europeas se producen unas cuatro lesiones que incapacitan de forma permanente, como daños en el cerebro o la médula espinal, ocho lesiones graves y cincuenta lesiones leves, se ha analizado el impacto de estos servicios en la gravedad del accidente, considerando el número de víctimas totales, heridos graves y muertos y heridos leves. Por último, y considerando que este tipo de servicios puede contribuir a una transferencia desde el vehículo particular a otros modos de transporte, fomentando la intermodalidad y cubriendo la "última milla" de los servicios de transporte más rígidos, dotando de mayor capilaridad y alcance a las redes troncales de transporte colectivo, se ha analizado si estos servicios complementan o sustituyen al transporte público para reducir la accidentalidad. Para ello, se ha realizado un análisis de regresión utilizando un modelo binomial negativa de efectos aleatorios (RENB). Se ha escogido el municipio de Madrid por razones relacionadas con la oferta de servicios y disponibilidad de datos suficientes para formular el modelo matemático. Los resultados muestran que desde la llegada de Uber y Cabify al municipio de Madrid los accidentes -con al menos un herido grave o muerto- y con presencia de alcohol o drogas se han reducido en torno al 98%. Del mismo modo, también se observa un descenso, de aproximadamente un 18%, en el número de accidentes -con al menos un herido grave o muerto- producidos en fin de semana y festivo. Respecto a la gravedad del accidente, los resultados obtenidos muestran una reducción en el número de heridos graves y muertos de entorno al 25%. Sin embargo, el número de víctimas totales y el número de heridos leves ha aumentado un 3% y un 5% respectivamente. Finalmente, se ha observado que el número de heridos graves y muertos ha disminuido tanto en la "Almendra Central" (30.5%) como en la periferia (54.9%) del municipio, siendo mayor el impacto de estas plataformas en los distritos periféricos -con menor presencia de transporte público-. Además, el número de accidentes (con al menos un herido grave o un muerto) en fin de semana y festivo ha disminuido en ambas zonas, siendo de nuevo el impacto más notable en las zonas periféricas con un 54.9% frente a un 49.7%. El número de heridos leves también han disminuido en los distritos periféricos de la ciudad un 24,6%. Sin embargo, el número de heridos leves ha aumentado un 5.7% en la "Almendra Central" donde el 73% de los desplazamientos se realizan en transporte público. En general, los resultados encontrados en este estudio apoyarían la hipótesis de que estos servicios sustituyen al transporte público, en especial a los autobuses urbanos. Sin embargo, estos servicios mejoran la oferta a los usuarios con mayores dificultades para acceder a los taxis o al transporte público, constituyendo un modo de transporte alternativo para los conductores de alto riesgo. Por lo tanto, estos hallazgos pueden ser muy útiles para que los responsables políticos definan mejor las políticas reguladoras de estos servicios.

When striving to develop towards sustainability, reducing private car use is a crucial factor. The most convenient alternative is to replace the private car with public transport. Fast public transport types, such as trains, have large catchment areas, thus walking to the station can be time consuming and increases door-to-door travel time compared with the private car. An alternative to this is bike-and-ride, i.e. cycling to the transit station and continuing with public transport. This study aims to find ways to increase public transport use, focusing on cycling between the home and the transit station. This is done through a literature study and a case study in Knivsta, a suburban area of Stockholm connected to the city center through commuter trains. Improvements in the current bike-and-ride infrastructure in Knivsta are suggested, using the principles of Transit Oriented Development and Theory of Planned Behavior as guidelines. The most important aspects of high bike-and-ride proportions is the provision of separate bicycle paths and plentiful high-quality bicycle parking at transit stations. The current situation in Knivsta is inadequate with few separate bicycle paths and the bicycle parking does not fulfil recommendations. Suggestions for improvements are proposed, with developing a regional bicycle highway network in addition to other bicycle paths throughout the town of Knivsta, in addition to increased and improved bicycle parking at Knivsta train station to fulfil the requirements of the future as Knivsta is expected to double in population towards 2030. The changes proposed to the bicycle infrastructure in Knivsta have potential to increase public transport use, decreasing private car and park-and-ride use. Due to the bicycle network being convenient and accessible for virtually everyone, the municipality will develop towards environmental, economic, and social sustainability.

Sharing automated vehicles (AVs) is a possible future, where shared automated vehicles (SAVs) and pooled automated vehicles (PooledAVs) are prospective on-demand AV configurations. While SAVs and PooledAVs can contribute to the sustainability of transport systems, the success of on-demand AVs depends on whether and how the public adopts them as regular travel modes. As such, this dissertation investigates five objectives: (1) to scrutinize the essential steps of designing a future mobility survey , while the primary focus of the survey is on respondents’ intentions to adopt various AV configurations (2) to propose and validate a theoretical model for on-demand AV adoption by extending the Theory of Planned Behavior (TPB), (3) to identify the prospective use cases of SAVs as the potential precursor of on-demand AVs, (4) to identify individual characteristics that may trigger different behavioral intentions among the on-demand AV service types, and finally (5) to investigate Canadians’ intentions to adopt on-demand AVs. A nationwide Canadian survey was designed and administered in fall 2021 (n = 5002) among adults (18 to 75 years old) residing in six major Canadian metropolitan areas: Toronto, Vancouver, Ottawa-Gatineau, Montréal, Calgary, and Hamilton. The findings of this dissertation paint a complex picture of on-demand AV adoption in the Canadian context with respect to the application of constructs from common technology adoption models and will help researchers investigating the characteristics of prospective consumers of on-demand AVs to identify the importance of affective motivations regarding adopting such emerging travel modes. The results reveal that many Canadians are yet either uncertain or reluctant to adopt AV technology in shared mobility services. In this light, policymakers and planners should adjust and moderate their expectations regarding the future market for on-demand AVs and be prepared for potential changes in travel behavior by examining incremental changes in existing on-demand ride-hailing services. / Dissertation / Doctor of Philosophy (PhD) / This dissertation assesses the conditions under which Canadians are willing to use fully automated vehicles (AVs) and investigates public perceptions and intentions to use “automated ride-hailing services,” which function as a taxi or Uber/Lyft service without a driver, and “pooled automated ride-hailing services,” which are a form of ride-hailing services, where passengers share a ride with someone they do not know to save on the cost of travel. To this end, an online survey (n = 5002) was designed and administered in October and November 2021 across six major Canadian metropolitan areas: Toronto, Vancouver, Ottawa-Gatineau, Montreal, Calgary, and Hamilton. Overall, results suggest that expectations towards AVs suddenly transforming the entire transportation sector, should be moderated and “automated ride-hailing services” and “pooled automated ride-hailing services” (when they are available in the entire Canadian market) are likely to be adopted as a supplementary mobility tool rather than a substitution for current travel modes.

Noise and vibration transmitted through the tire and suspension system are strong indicators of overall vehicle ride quality. Often, during the tire design process, target specifications are used to achieve the desired ride performance. To validate the design, subjective evaluations are performed by expert drivers. These evaluations are usually done on a test track and are both quite expensive and time consuming due to the several experimental sets of tires that must be manufactured, installed, and then tested on the target vehicle. In order to evaluate the performance, expert drivers tune themselves to the frequency response of the tire/vehicle combination. Provided the right models exist, this evaluation can also be achieved in a laboratory. The research presented here is a method which utilizes the principles of frequency based substructuring (FBS) to separate or combine frequency response data for the tire and suspension. This method allows for the possibility of combining high fidelity tire models with analytical or experimental suspension data in order to obtain an overall response of the combined system without requiring an experimental setup or comprehensive simulations. Though high fidelity models are not combined with experimental data in the present work, these coupling/decoupling techniques are applied independently to several quarter car models of varying complexity and to experimental data. These models range from a simplified spring-mass model to a generalized 3D model including rotation. Further, decoupling techniques were applied to simulations of a rigid ring tire model, which allows for inclusion of nonlinearities present in the tire subsystem and provides meaningful information for a loaded tire. By reducing the need for time consuming simulations and experiments, this research has the potential to significantly reduce the time and cost associated with tire design for ride performance. In order to validate the process experimentally, a small-scale quarter car test rig was developed. This novel setup was specifically designed for the challenges associated with the testing necessary to apply FBS techniques to the tire and suspension systems. The small-scale quarter car system was then used to validate both the models and the testing processes unique to this application. By validating the coupling/decoupling process for the first time on the tire/vehicle system with experimental data, this research can potentially improve the current process of tire design for ride performance. / Ph. D.

The ride stability of an A-train 28-foot double tractor trailer when outfitted with different Roll Stability Control (RSC) systems with the same payload and suspension configurations is studied experimentally for various dynamic maneuvers. The primary goal of the study is to determine the effect of different commercially-available RSC systems on the extent of improvements they offer for increasing roll stability of commercial vehicles with double trailers, when subjected to limit-steering maneuvers that can rise during highway driving. A semitruck and two 28-foot trailers are modified for enduring the forces and moments that can result during testing. A load structure is used for placing the ballast loads within the trailers at a suitable height for duplicating the CG height of the trailers during their commercial use. Outriggers and jackknifing arresting mechanisms are used to prevent vehicle damage and ensure safety during the tests. The test vehicle is equipped with multiple sensors and cameras for the necessary measurements and observations. The analog and video data are time-synced for correlating the measurements with visual observation of the test vehicle dynamics in post-processing. An extensive number of tests are conducted at the Michelin Laurens Proving Grounds (MLPG) in Laurens, SC. The tests include evaluating each RSC system with different maneuvers and speeds until a rollover occurs or the vehicle is deemed to be unstable. The maneuvers that are used for the tests include: double lane change, sine-with-dwell, J-turn, and ramp steer maneuver. Both a steering robot and subjective driver are used for the tests. The test data are analyzed and the results are used to compare the three RSC systems with each other, and with trailers without RSC. The test results indicate that all three RSC systems are able to improve the speed at which rollover occurs, with a varying degree. For two of the systems, the rollover speed gained, when compared with trailers without RSC, is marginal. For one of the systems, there are more significant speed gains. Since most RSC systems are tuned for a conventional tractor-trailer, additional testing with some of the systems would be necessary to enable the manufacturers to better fine-tune the RSC control scheme to the dynamics of double trailers. / MS

Thesis (MScEng)--Stellenbosch University, 2012. / ENGLISH ABSTRACT: The slip synchronous-permanent magnet generator (SS-PMG) is a direct-driven, direct-to-grid generator for wind turbine applications. This investigation focuses on achieving automated grid connection and low voltage ride-through for a small-scale SS-PMG. To reduce cost and complexity, components such as blade pitch controllers and frequency converters are avoided. Instead, electromagnetic braking is employed to control turbine speed prior to grid synchronisation and compensation resistances are used to facilitate grid fault ride-through. The conditions under which the SS-PMG can be successfully synchronised with the grid are determined, indicating a need for speed control. An evaluation of electromagnetic braking strategies reveals that satisfactory speed control performance can be achieved when employing back-to-back thyristors to switch in the braking load. Simulations show that controlled synchronisation can be executed successfully under turbulent wind conditions. All controllable parameters are held within safe limits, but the SS-PMG terminal voltage drop is higher than desired. Compensation is developed to allow the SS-PMG to ride through the voltage dip profile specified by the Irish distribution code. It is found that a combination of series and shunt resistances is necessary to shield the SS-PMG from the voltage dip, while balancing active power transfer. The flexibility offered by thyristor switching of the shunt braking load is instrumental in coping with turbulent wind conditions and unbalanced dips. The South African voltage dip profile is also managed with conditional success. Following on from the theoretical design, the grid connection controller is implemented for practical testing purposes. Protection functions are developed to ensure safe operation under various contingencies. Before testing, problems with the operation of the thyristors are overcome. Practical testing shows that grid synchronisation can be undertaken safely by obeying the theoretically determined conditions. The speed control mechanism is also shown to achieve acceptable dynamic performance. Finally, the SS-PMG is incorporated into a functioning wind turbine system and automated grid connection is demonstrated under turbulent wind conditions. Future investigations may be focused on optimal control strategies, alternative solid-state switching schemes, and reactive power control. Low voltage ride-through should also be optimised for the South African dip profile and validated experimentally. / AFRIKAANSE OPSOMMING: Die glip-sinchroon permanente magneet generator (GS-PMG) is ‘n direkte dryf, direkte netwerkgekoppelde generator vir windturbine toepassings. Hierdie ondersoek fokus op die bereiking van ’n ge-outomatiseerde netwerkkoppeling en lae spanning deurry vir ‘n kleinskaalse GS-PMG. Om kostes en kompleksiteit te verminder, word komponente soos lemsteekbeheerders en frekwensie-omsetters vermy. In plaas daarvan word elektromagnetiese remwerking gebruik om die turbine spoed, voorgaande net-werksinchronisasie, te beheer, en word kompensasieweerstande gebruik om netwerkfoutdeurry te handhaaf. Die omstandighede waaronder die GS-PMG suksesvol met die netwerk gesinchroniseer kan word, is vasgestel en dit het die behoefte aan spoedbeheer uitgewys. ‘n Evaluering van elektromagnetiese remstrategië wys uit dat ’n bevredigende spoedbeheervermoë verkry kan word as anti-parallelle tiristors gebruik word om die remlas te skakel. Simulasies wys dat beheerde netwerksinchronisasie suksesvol uitgevoer kan word, selfs onder turbulente windtoestande. Alle beheerbare parameters is binne veilige perke gehou, maar die GS-PMG se klemspanningsval is gevind as hoë as verwag. Kompensasie is ontwikkel om die GS-PMG toe te laat om deur die spanningsvalprofiel, soos gespesifieer deur die Ierse distribusiekode, te ry. Dit is gevind dat ‘n kombinasie van serie- en parallelle weerstande nodig is om die GS-PMG teen die spanningsval te beskerm, terwyl aktiewe drywingsoordrag gebalanseer word. Die buigbaarheid wat verkry word met die tiristorskakeling van die parallele weerstand is noodsaaklik in die hanteering van turbulente windtoestande en ongebalanseerde spanningsvalle. Die Suid-Afrikaanse spanningsvalprofiel is ook met voorwaardelike sukses hanteer. In opvolg van die teoretiese ontwerp is die netwerkkoppelingsbeheerder vir praktiese toetsdoeleindes in werking gestel. Beskermingsfunksies is ontwikkel om veilige werking onder verskeie gebeurlikhede te verseker. Die probleme met die werking van die tiristors is oorkom voor die aanvang van die toetse. Die praktiese toetse bewys dat netwerksinchronisasie veilig gedoen kan word deur die teoretiese bepaalde voorwaardes te volg. Dit is ook getoon dat met die spoedbeheermeganisme aanvaarbare dinamiese gedrag verkry kan word. Ten laaste is die GS-PMG in ‘n werkende windturbinestelsel geïnkorporeer en outomatiese netwerkkoppeling is onder turbulente windtoestande gedemonstreer. Toekomstige ondersoeke kan toegespits word op optimale beheerstrategië, alternatiewe vaste toestand skakelingskemas en reaktiewe drywingsbeheer. Lae spanning deurry moet nog vir die Suid- Afrikaanse spanningsprofiel ge-optimeer en eksperimenteel bevestig word.

La géothermie est considérée comme une source d'énergie propre et inépuisable à échelle humaine. Actuellement, le rendement des centrales géothermiques est limité à l'exploitation de fluides de températures inférieures à 300°C. L'association de l'activité tectonique et volcanique aux dorsales océaniques fait de l'Islande un lieu où l'extraction de fluides supercritiques (T°>400°C) peut être envisagée. Cette exploitation pourrait multiplier par dix la puissance électrique délivrée par les puits géothermiques. Ces fluides peuvent-ils circuler dans la croûte océanique ? Ce travail propose de contraindre les observations géophysiques et de prédire le fonctionnement des réservoirs hydro-géothermaux de très haute température par l'étude des propriétés physiques des basaltes. La première approche est focalisée sur l'étude de roches ayant accueilli une circulation hydrothermale par le passé. L'étude de ces roches au site ODP 1256, montre que leur porosité est associée à la présence de minéraux d'altération hydrothermale du faciès amphibolite (T°>500°C ). La seconde approche a consisté à recréer en laboratoire les conditions des systèmes hydrothermaux à très haute température afin de prédire les propriétés mécaniques et électriques des basaltes dans ces conditions. Les résultats mécaniques indiquent que la transition fragile/ductile, souvent associée à une forte décroissance de perméabilité, intervient à une température d'environ 550°C. La mise en place d'une cellule de mesure de la conductivité électrique de haute températures a fournit les premiers résultats utiles à l'analyse des données géophysiques. Appliqués aux conditions de la croûte basaltique Islandaise, ces résultats indiquent que des fluides hydrothermaux pourraient circuler au moins transitoirement à l'état supercritique jusqu'à ~ 5 km de profondeur. / Geothermal energy is considered as a green and infinite energy source at human scale. Currently, the yield of geothermal power plants is limited to temperatures of the operating fluid which 300 °C. From tectonic and volcanic activity at mid-ocean ridges, Iceland is a locuswhere supercritical fluid extraction (T > 400° C) can considered for the near future. Exploiting such fluids could theoretically multiply by a factor of ten the electrical power delivered by geothermal wells. Can such fluids circulate at the base of brittle oceanic crust? This work investigates the petrophysical properties of basalts in order to constrain geophysical observations in Iceland and predict the behavior of very high temperature hydro-geothermal reservoirs. The first approach consisted in studying the physical properties of rocks that have hosted deep hydrothermal circulations at oceanic ridges. The study of these rocks at ODP Site 1256 shows that the porosity mea sured both in the field and in the lab is associated with amphibolite facies alteration minerals (T > 500° C). The second approach was to recreate in the laboratory the conditions of pressure, temperature and pore fluid pressure of high temperature to supercritical hydrothermal systems to predict the mechanical and electrical properties of basalts under these conditions. The mechanical results indicate that the brittle/ductile transition occurs at a temperature of about 550° C, where a strong permeability decrease is expected. The implementation and calibration of a new cell for measuring electrical conductivity at high temperature provide the first results for the interpretation of geophysical data. When applied to basaltic crustal conditions in Iceland, these results indicate that hydrothermal fluids could circulate, at least temporarily, in a supercritical state up to 5 km depth.

A designação de estruturas próprias de sistemas dinâmicos com retroação completa de estados ou saídas foi objeto de estudo de muitos pesquisadores durante a segunda metade do século XX. Os trabalhos mais relevantes sobre o tema foram revisados e serviram como base para a elaboração da metodologia apresentada neste trabalho. Que consiste na designação de estruturas próprias desejadas para um sistema linear em malha aberta com a modificação de parâmetros do sistema através da pseudo retroação de saídas devidamente definidas. O método foi aplicado na coxinização de um veículo de passeio. No qual os modos de vibrar de modelos lineares com 7 e 8 graus de liberdade do veículo foram adequados com o intuito de reduzir as acelerações verticais de chassi, características do fenômeno shake de motor e câmbio (faixa de frequência entre 7 e 25 Hz). Para tanto, reduziu-se a participação do grau de liberdade vertical de chassi nos modos com grande participação dos graus de liberdade de motor e massa não suspensa. Os resultados obtidos com a aplicação da metodologia na coxinização foram valores de rigidezes, amortecimentos e características de coxins hidráulicos que resultam na redução significativa da aceleração vertical de chassi, que implica em uma melhora perceptível para o consumidor na qualidade do conforto do veículo. / Eigenstructure assignment using full state or output feedback control had been object of study of many researchers during the second half of XX century. The most important works about eigenstructure assignment were reviewed, specially some applications within aerospace industry, that was the responsible for developing all the theory concerning pole and eigenvector placement. The review of the related theory was also based on the pioneering and most expressive works and were base for the methodology developed and described in this work. Which consists basically on the assignment of some desired eigensctructure of open loop linear systems modifying some parameters of the systems by means pseudo feedback of some outputs into inputs specifically defined. This methodology was applied to a 8 DOF vehicle model, a case of study, in order to adequate the system modes changing engine mounts parameters to improve the vehicle ride comfort, mainly eigenstructures about powertrain shake range frequencies.

Este trabalho apresenta o estudo da dinâmica vertical de um veículo off-road de competição e do comportamento elastocinemático de suas suspensões primárias de duplo estágio com o auxílio da ferramenta computacional de simulação de sistemas multicorpos MSC-ADAMS. O modelo multicorpos do veículo inclui os modelos da suspensão dianteira, suspensão traseira, sistema de direção, pneus e massa suspensa. As análises elastocinemáticas das suspensões definiram geometrias que permitem longos cursos de trabalho das suspensões sem variações indesejadas de parâmetros de projeto. Com a análise modal do modelo de veículo completo foram definidos os valores de rigidez das molas das suspensões de duplo estágio que resultaram em valores de freqüência natural no primeiro estágio semelhantes aos indicados para carros de passeio e no segundo estágio, próximos dos encontrados em veículos de competição. A análise de conforto do veículo durante simulação de passagem por trecho de pista demonstrou que os elementos de força definidos na análise modal resultam em níveis de conforto raramente encontrados em veículos de competição. / This dissertation presents the study of a off-road competition vehicle ride and the double rate suspensions elastokinematic behavior using the multibody software MSC-ADAMS. The vehicle multibody model includes the rear and front suspensions, the steering system, the tires and the sprung mass. The suspensions elastokinematic analysis defined geometric configurations that allowed long jounce and rebound travel of wheel, without undesirable project parameters variations. In the modal analysis of the vehicle multibody model, the springs rates that results in natural frequencies values similar to passenger cars for the first suspension stage and, for the second stage, similar to competition vehicles, were defined. The ride analysis during the simulation of the vehicle running on a rough track showed that the force elements defined on the modal analysis resulted in a good ride quality, rarely found in competition vehicles.

<p>U ovoj doktorskoj disertaciji razvijena je tehnika upravljanja za<br />pretvarač energetske elektronike pri nesimetričnim naponskim<br />prilikama u elektroenergetskom sistemu. Kao što je pokazano,<br />primenom tehnike poništavanja signala kašnjenjem moguće je<br />izdvajanje komponenti struje inverznog redosleda i njihovo<br />potpuno poništenje, što će omogućiti pouzdanu kontrolu<br />komponenti struje direktnog redosleda upotrebom klasičnih<br />tehnika upraljanja, uz adekvatno unapređenje tehnike za<br />sinhronizaciju sa vektorskim reprezentom napona. Predložena<br />je i upotreba algoritama za poboljšanje parametara kvaliteta<br />električne energije bez dodatnih pasivnih elemenata.</p> / <p>This PhD thesis presents an improved control technique for grid<br />connected converter under asymmetrical voltages at the point of<br />common coupling. As presented, using delay signal cancellation<br />technique it is possible to differentiate and completely mitigate the<br />negative sequence current, offering the possibility of reliable positive<br />sequence current control using classical control algorithms. The<br />improvements made in synchronization offered adequate<br />phase angle estimation under voltage asymmetry. Furthermore, a<br />technique for the improvement of power quality indices without<br />passive elements between the grid and</p>