Nowadays the needs to fulfill severe emission standards and to reduce the mobile machine operative costs have driven the off-highway industrial research towards new solutions able to increase the overall vehicle efficiency. Within this scenario, smart power split transmissions demonstrated to be a very attractive technology able to achieve the fuel consumption reduction targets, increasing the machine working cycle productivity. Compared to the standard technologies (such as Torque Converters - TC), the power split hydromechanical varible transmissin (HVT), designed and developed by Dana Rexroth Transmission Systems S.r.l. (DRTS), is able to fully decouple the engine to wheel behavior during the machine working cycle, with an higher efficiency than a pure hydrostatic transmission. Due to this fundamental characteristic, the HVT allows the engine to work next to the maximum efficiency point, consequently it is possible to downsize the engine to further increase the fuel saving. The analysis of the field test performed by an off-highway vehicle (Kalmar Cargotec DRG Gloria 450 reachstacker) equipped with a DRTS HVT has been shown along this paper; particular attention has been given to the cycle load spectra, the fuel consumption and the working cycle productivity through a comparison with standard TC technologies.

The popularity of wireless communication has increased substantially over the last decade, due to mobility support, flexibility and ease of deployment. Among next generation of mobile communication technologies, Ad Hoc networking plays an important role, since it can stand alone as private network, become a part of public network, either for general use or as part of disaster management scenarios. The performance of multihop Ad Hoc networks is heavily affected by interference, mobility, limited shared bandwidth, battery life, error rate of wireless media, and the presence of hidden and exposed terminals. The scheduler and the Medium Access Control (MAC) play a vital role in providing Quality of Service (QoS) and policing delay, end-to-end throughput, jitter, and fairness for user application services. This project aims to optimise the usage of the available limited resources in terms of battery life and bandwidth, in order to reduce packet delivery time and interference, enhance fairness, as well as increase the end-to-end throughput, and increase the overall network performance. The end-to-end throughput of an Ad Hoc network decays rapidly as the hop count between the source and destination pair increases and additional flows injected along the path of an existing flow affects the flows arriving from further away; in order to address this problem, the thesis proposes a Hop Based Dynamic Fair Scheduler that prioritises flows subject to the hop count of frames, leading to a 10% increase in fairness when compared to a IEEE 802.11b with single queue. Another mechanism to improve network performance in high congestion scenarios is network-aware queuing that reduces loss and improve the end-to-end throughput of the communicating nodes, using a medium access control method, named Dynamic Queue Utilisation Based Medium Access Control (DQUB-MAC). This MAC provides higher access probability to the nodes with congested queue, so that data generated at a high rate can be forwarded more effectively. Finally, the DQUB-MAC is modified to take account of hop count and a new MAC called Queue Utilisation with Hop Based Enhanced Arbitrary Inter Frame Spacing (QU-EAIFS) is also designed in this thesis. Validation tests in a long chain topology demonstrate that DQUB-MAC and QU-EAIFS increase the performance of the network during saturation by 35% and 40% respectively compared to IEEE 802.11b. High transmission power leads to greater interference and represents a significant challenge for Ad Hoc networks, particularly in the context of shared bandwidth and limited battery life. The thesis proposes two power control mechanisms that also employ a random backoff value directly proportional to the number of the active contending neighbours. The first mechanism, named Location Based Transmission using a Neighbour Aware with Optimised EIFS for Ad Hoc Networks (LBT-NA with Optimised EIFS MAC), controls the transmission power by exchanging location information between the communicating nodes in order to provide better fairness through a dynamic EIFS based on the overheard packet length. In a random topology, with randomly placed source and destination nodes, the performance gain of the proposed MAC over IEEE 802.11b ranges from approximately 3% to above 90% and the fairness index improved significantly. Further, the transmission power is directly proportional to the distance of communication. So, the performance is high and the durability of the nodes increases compared to a fixed transmission power MAC such as IEEE 802.11b when communicating distance is shorter. However, the mechanism requires positional information, therefore, given that location is typically unavailable, a more feasible power control cross layered system called Dynamic Neighbour Aware – Power controlled MAC (Dynamic NA -PMAC)is designed to adjust the transmission power by estimating the communicating distance based on the estimated overheard signal strength. In summary, the thesis proposes a number of mechanisms that improve the fairness amongst the competing flows, increase the end-to-end throughput, decrease the delay, reduce the transmission power in Ad Hoc environments and substantially increase the overall performance of the network.

Nowadays the needs to fulfill severe emission standards and to reduce the mobile machine operative costs have driven the off-highway industrial research towards new solutions able to increase the overall vehicle efficiency. Within this scenario, smart power split transmissions demonstrated to be a very attractive technology able to achieve the fuel consumption reduction targets, increasing the machine working cycle productivity. Compared to the standard technologies (such as Torque Converters - TC), the power split hydromechanical varible transmissin (HVT), designed and developed by Dana Rexroth Transmission Systems S.r.l. (DRTS), is able to fully decouple the engine to wheel behavior during the machine working cycle, with an higher efficiency than a pure hydrostatic transmission. Due to this fundamental characteristic, the HVT allows the engine to work next to the maximum efficiency point, consequently it is possible to downsize the engine to further increase the fuel saving. The analysis of the field test performed by an off-highway vehicle (Kalmar Cargotec DRG Gloria 450 reachstacker) equipped with a DRTS HVT has been shown along this paper; particular attention has been given to the cycle load spectra, the fuel consumption and the working cycle productivity through a comparison with standard TC technologies.

The thesis deals with connectedness in the uncertainty of the carbon and power markets in Central Europe. While the drivers of power price were extensively documented in the literature, we investigate how uncertainty propagates between the German power market and its production factors using a recently developed framework of connectedness measurement. The connections in uncertainty on markets are insightful for the decision of the agents that require a premium for undertaking risk. The empirical results suggest that connectedness in uncertainty significantly varies over the studied period. The interdependence of power with coal decreases while the spillovers between gas and power rise on importance reflecting the changes in generation mix of Germany. For most of the period, the volatility of carbon and power markets is highly correlated. However, the share of volatility transmission spikes several times during the period of 2016-2019. In reaction to the reform of the EU Emission Trading Scheme, the uncertainty about emission allowance prices propagates to the German power market, increasing the uncertainty about power prices on the long horizon.

Hydraulic systems represent a crucial part of the drivetrain of mobile machines. The most important drivers of current developments, increasing energy efficiency and productivity, are leading to certain trends in technology. On a subsystem level, working hydraulics are utilizing effects by improving control functions and by maximum usage of energy recovery potential. Independent metering and displacement control, partly in combination with hybrid concepts, are the dominating approaches. Traction drives gain advantage from optimized power split transmissions, which consequently are being used in a growing number of applications. On the level of components, increase of efficiency and dynamics as well as power density are important trends. Altogether, design of systems and components is more and more based on modular concepts. In this sense, among others, sensors and control elements are being integrated to actuators; electric and hydraulic technology is being merged. In order to achieve maximum efficiency and performance of the entire machine, control of hydraulics has to include the whole drivetrain and the entire mobile machine in its application. In modern words, mobile hydraulic systems are a part of cyber physical systems.

The purpose of this investigation is to identify appropriate location of capacitor banks and sources of reactive power by studying power system stability in the vicinity of system equilibrium states. The locations for reactive power sources are determined by identifying those modes of the system that participate most in the system behavior in general and in dictating the final state of the system after experiencing faults or disturbances. To identify the relevant modes of the system that participate most in the system dynamic, we shall make use of modal and participation analysis for different system conditions. We also apply modal and participation analysis to a system in order to identify the components of greatest impact that result in the most efficient system control. The ideas developed in this study are used to analyze and identify weak boundaries of the IEEE 39- Bus system that contribute to the system’s instability.

Orientadores: Carlos Alberto de Castro Junior, Manfred Fritz Bedriñana Aronés / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Elétrica e de Computação / Made available in DSpace on 2018-08-16T06:40:59Z (GMT). No. of bitstreams: 1 Tavares_BeatrizdeLima_M.pdf: 2516787 bytes, checksum: 8462455ea7f9f76c7dd5ebef70a70ace (MD5) Previous issue date: 2010 / Resumo: Neste trabalho são apresentados dois métodos para a obtenção do ponto de máximo carregamento (PMC). Ambos os processos de cálculo baseiam-se nas propriedades do vetor normal à fronteira de factibilidade calculado próximo ao PMC através de um método de fluxo de carga com otimização de passo (FCOP). No primeiro método o processo é caracterizado pela obtenção de sucessivas aproximações do PMC a partir da região de infactibilidade. Pelo fato da fronteira de factibilidade não ser sempre convexa, algumas vezes o ponto obtido poderá cair na região factível. Neste caso, um novo método de cálculo do fator de carregamento que garante que o próximo ponto estará na região infactível é a principal contribuição. Já o segundo é um método rápido e prático para o cálculo do ponto de máximo carregamento (PMC), em que é adicionado um procedimento prático ao processo de cálculo global para incluir a informação do operador da rede com a definição de um erro aceitável no resultado final. O PMC é facilmente obtido após alguns passos, demonstrando a eficácia do método proposto. Os resultados de simulações com sistemas teste do IEEE e sistemas reais são apresentados para validar as duas metodologias / Abstract: In this paper, two maximum loading point (MLP) calculation methods are proposed. In both cases, the calculation process is based on the properties of the normal vector to the feasibility boundary computed close to MLP, which is calculated by a load flow method with step size optimization (LFSSO). In the first method the process is characterized by obtaining consecutive approximations of the MLP from the infeasible region. Since the feasibility boundary contour in the neighborhood of the MLP may not be smooth, some of the computed points may fall within the feasible region. In this case, a new load factor calculation method that guarantees that the next solution will lay within the infeasibility region is the main contribution. The second one is a practical and fast method to obtain the MLP, where a practical procedure is added to the overall calculation process to include the operator's information on the acceptable error in the final result. The MLP is accurately obtained after just a few steps, demonstrating the efficiency of the proposed method. Simulation results for IEEE test and realistic systems are shown to validate both proposed methods / Mestrado / Energia Eletrica / Mestre em Engenharia Elétrica

Offshore oil production presents major challenges due to extreme environmental conditions. With present state of the art robotics, precision mechanics and automation it is now possible to provide solutions to those working conditions. The present work is part of a solution to the problem of the unblocking a subsea oil pipeline of small diameter and extensive length by designing and manufacturing a robot capable of moving inside the pipeline. Based on the previous study of an interdisciplinary group, the implementation of an umbilical cable was defined with the purpose of assuring the supply of electrical power for the robot’s energy requirements, control signals and a mechanical link to avoid the possibility of getting stuck. Similarly, the robot's movement strategy was defined based on a high reliability mechanism, capable of overcoming the great tension resulting from the interaction of the long umbilical cable with the inside of the pipe. In this work, the mechanical design is performed to implement a robot capable of overcoming big cable tensions with small components, integrating commercial components and others custom made. A solution was implemented to convert the electric power received through the cable to the mechanical power in the form required by the displacement mechanism. For this, a detailed engineering design is presented that integrates a high performance electric motor, a two-stage planetary gear transmission for high reduction ratio, a power split transmission driven by disc clutches and a mechanical power distribution stage required by the mechanism responsible for the displacement. / La producción de petróleo offshore presenta grandes desafíos por las condiciones en que se lleva a cabo, actualmente es posible darle solución con la ayuda de la robótica, la mecánica de precisión y la automatización. El presente trabajo es parte de una solución al problema de la desobstrucción en una tubería de petróleo submarina de pequeño diámetro y largo tendido mediante el diseño y la construcción de un robot capaz de trasladarse por el interior de la misma. En base al estudio previo de un grupo interdisciplinario se definió la implementación de un cable umbilical con el propósito de asegurar el suministro de potencia eléctrica para los requerimientos de energía de robot, el enlace de señales destinadas al control y un vínculo mecánico para proveer seguridad ante un eventual desperfecto. Similarmente se definió la estrategia de movimiento del robot en base a un mecanismo de alta confiabilidad, capaz de vencer una gran tensión producto de la interacción del largo cable umbilical con el interior de la tubería. En este trabajo se realiza el diseño mecánico para implementar un robot capaz de realizar grandes esfuerzos con componentes de tamaño reducido, integrando componentes comerciales y otros hechos a medida. Para ello, se implementó una solución para convertir la potencia eléctrica recibida a través del cable a la potencia mecánica en la forma requerida por el mecanismo que da lugar al movimiento. Para dicha solución se presenta un diseño detallado que integra un motor eléctrico de alto desempeño, una transmisión planetaria reductora de dos etapas, una transmisión inversora accionada por embragues de discos y una etapa de distribución de potencia mecánica requerida por el mecanismo responsable del movimiento.

Offshore oil production presents major challenges due to extreme environmental conditions. With present state of the art robotics, precision mechanics and automation it is now possible to provide solutions to those working conditions. The present work is part of a solution to the problem of the unblocking a subsea oil pipeline of small diameter and extensive length by designing and manufacturing a robot capable of moving inside the pipeline. Based on the previous study of an interdisciplinary group, the implementation of an umbilical cable was defined with the purpose of assuring the supply of electrical power for the robot’s energy requirements, control signals and a mechanical link to avoid the possibility of getting stuck. Similarly, the robot's movement strategy was defined based on a high reliability mechanism, capable of overcoming the great tension resulting from the interaction of the long umbilical cable with the inside of the pipe. In this work, the mechanical design is performed to implement a robot capable of overcoming big cable tensions with small components, integrating commercial components and others custom made. A solution was implemented to convert the electric power received through the cable to the mechanical power in the form required by the displacement mechanism. For this, a detailed engineering design is presented that integrates a high performance electric motor, a two-stage planetary gear transmission for high reduction ratio, a power split transmission driven by disc clutches and a mechanical power distribution stage required by the mechanism responsible for the displacement. / La producción de petróleo offshore presenta grandes desafíos por las condiciones en que se lleva a cabo, actualmente es posible darle solución con la ayuda de la robótica, la mecánica de precisión y la automatización. El presente trabajo es parte de una solución al problema de la desobstrucción en una tubería de petróleo submarina de pequeño diámetro y largo tendido mediante el diseño y la construcción de un robot capaz de trasladarse por el interior de la misma. En base al estudio previo de un grupo interdisciplinario se definió la implementación de un cable umbilical con el propósito de asegurar el suministro de potencia eléctrica para los requerimientos de energía de robot, el enlace de señales destinadas al control y un vínculo mecánico para proveer seguridad ante un eventual desperfecto. Similarmente se definió la estrategia de movimiento del robot en base a un mecanismo de alta confiabilidad, capaz de vencer una gran tensión producto de la interacción del largo cable umbilical con el interior de la tubería. En este trabajo se realiza el diseño mecánico para implementar un robot capaz de realizar grandes esfuerzos con componentes de tamaño reducido, integrando componentes comerciales y otros hechos a medida. Para ello, se implementó una solución para convertir la potencia eléctrica recibida a través del cable a la potencia mecánica en la forma requerida por el mecanismo que da lugar al movimiento. Para dicha solución se presenta un diseño detallado que integra un motor eléctrico de alto desempeño, una transmisión planetaria reductora de dos etapas, una transmisión inversora accionada por embragues de discos y una etapa de distribución de potencia mecánica requerida por el mecanismo responsable del movimiento.

Offshore oil production presents major challenges due to extreme environmental conditions. With present state of the art robotics, precision mechanics and automation it is now possible to provide solutions to those working conditions. The present work is part of a solution to the problem of the unblocking a subsea oil pipeline of small diameter and extensive length by designing and manufacturing a robot capable of moving inside the pipeline. Based on the previous study of an interdisciplinary group, the implementation of an umbilical cable was defined with the purpose of assuring the supply of electrical power for the robot’s energy requirements, control signals and a mechanical link to avoid the possibility of getting stuck. Similarly, the robot's movement strategy was defined based on a high reliability mechanism, capable of overcoming the great tension resulting from the interaction of the long umbilical cable with the inside of the pipe. In this work, the mechanical design is performed to implement a robot capable of overcoming big cable tensions with small components, integrating commercial components and others custom made. A solution was implemented to convert the electric power received through the cable to the mechanical power in the form required by the displacement mechanism. For this, a detailed engineering design is presented that integrates a high performance electric motor, a two-stage planetary gear transmission for high reduction ratio, a power split transmission driven by disc clutches and a mechanical power distribution stage required by the mechanism responsible for the displacement. / La producción de petróleo offshore presenta grandes desafíos por las condiciones en que se lleva a cabo, actualmente es posible darle solución con la ayuda de la robótica, la mecánica de precisión y la automatización. El presente trabajo es parte de una solución al problema de la desobstrucción en una tubería de petróleo submarina de pequeño diámetro y largo tendido mediante el diseño y la construcción de un robot capaz de trasladarse por el interior de la misma. En base al estudio previo de un grupo interdisciplinario se definió la implementación de un cable umbilical con el propósito de asegurar el suministro de potencia eléctrica para los requerimientos de energía de robot, el enlace de señales destinadas al control y un vínculo mecánico para proveer seguridad ante un eventual desperfecto. Similarmente se definió la estrategia de movimiento del robot en base a un mecanismo de alta confiabilidad, capaz de vencer una gran tensión producto de la interacción del largo cable umbilical con el interior de la tubería. En este trabajo se realiza el diseño mecánico para implementar un robot capaz de realizar grandes esfuerzos con componentes de tamaño reducido, integrando componentes comerciales y otros hechos a medida. Para ello, se implementó una solución para convertir la potencia eléctrica recibida a través del cable a la potencia mecánica en la forma requerida por el mecanismo que da lugar al movimiento. Para dicha solución se presenta un diseño detallado que integra un motor eléctrico de alto desempeño, una transmisión planetaria reductora de dos etapas, una transmisión inversora accionada por embragues de discos y una etapa de distribución de potencia mecánica requerida por el mecanismo responsable del movimiento.