5,165 research outputs found

    Development of Urban Electric Bus Drivetrain

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    The development of the drivetrain for a new series of urban electric buses is presented in the paper. The traction and design properties of several drive variants are compared. The efficiency of the drive was tested using simulation calculations of the vehicle rides based on data from real bus lines in Prague. The results of the design work and simulation calculations are presented in the paper

    Vehicle test report: Battronic pickup truck

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    An electric pickup truck was tested to characterize certain parameters and to provide baseline data that can be used for the comparison of improved batteries that may be incorporated into the vehicle at a later time. The vehicle tests were concentrated on the electrical drive subsystem; i.e., the batteries, controller, and motor. The tests included coastdowns to characterize the road load and range evaluations for both cyclic and constant speed conditions. A qualitative evaluation of the vehicle's performance was made by comparing its constant speed range performance with other vehicles

    Enhancing the programmability and energy efficiency of storage in hpc and virtualized environments

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    Mención Internacional en el título de doctorA decade ago computing systems hit a clock and power ceiling that places the energetic challenge among the most relevant issues in High Performance Computing (HPC). Motivated by the fact that computation is increasingly becoming cheaper than data movement in terms of power, our work studies and optimizes data movement across different levels of the software stack. We propose novel methodologies for analyzing, modeling, and optimizing the energy efficiency of data movement. More precisely, we propose methodologies to enhance the understanding of power consumption in the software I/O stack, and optimize the I/O energy efficiency in the operating system’s I/O stack, low-level CPU device drivers, and virtualized environments. Our experimental results show that through the understanding of the different operating system layers and their interaction, it is possible to develop novel coordination techniques that optimize the energy consumption and increase performance of I/O workloads. First, we develop a methodology for data collection, power and performance characterization, and modeling power usage in the I/O stack. Our work presents a detailed study of power and energy usage across all system components during various I/O-intensive workloads. We propose a data gathering methodology that combines software and hardware-based instrumentation in order to study I/O data movement, and develop novel power prediction models employing data analysis techniques. Second, this thesis presents novel CPU-level optimizations that improve the energy efficiency of I/O workloads. We address two issues present in modern processors: thermal imbalance causing performance variation and an inefficient use of CPU resources during I/O workloads. We develop novel techniques for power optimization and thermal efficiency through cross-layer coordination of CPU and I/O management. Third, we also focus on optimizing data sharing among virtual domains. In our work we refer to this as virtualized data sharing, which mainly differs from existing solutions by coordinating data flows through the software I/O stack. We develop a virtualized data sharing solution in order to reduce data movement among virtual environments, introducing new abstractions and mechanisms to more efficiently coordinate storage I/O.Hace una década, los computadores alcanzaron el límite físico de la frecuencia y potencia disipada, estableciendo el consumo energético como uno de los principales obstáculos en el campo de la computación de alto rendimiento. Motivados por el hecho de que la computación resulta cada vez menos costosa que el movimiento de datos en términos de energía, nuestro trabajo estudia y optimiza el movimiento de datos en varios niveles de la arquitectura software. En este trabajo proponemos nuevas metodologías para analizar, modelar y optimizar la eficiencia energética del movimiento de datos. Concretamente, proponemos metodologías para mejorar el análisis del consumo de potencia en la arquitectura software de E/S, así como optimizar la eficiencia energética de: la pila de E/S del sistema operativo, controladores de la CPU y entornos virtuales de E/S. Los resultados experimentales muestran que, mediante la comprensión de la interacción de las capas del sistema operativo, es posible desarrollar nuevas técnicas de coordinación que optimicen el consumo energético e incrementen el rendimiento de las cargas de trabajo de E/S. En primer lugar desarrollamos una metodología para la recolección de datos y la caracterización del rendimiento y consumo de potencia en la pila de E/S. Nuestro trabajo presenta un estudio detallado del consumo energético y de potencia de cada uno de los componentes del sistema durante la ejecución de cargas de trabajo de E/S. Concretamente proponemos una metodología de captura de datos que combina instrumentación hardware y software para estudiar el movimiento de datos, con el fin de desarrollar nuevos modelos de predicción de consumo empleando técnicas de análisis de datos. En segundo lugar, esta Tesis Doctoral presentamos nuevas optimizaciones a nivel de CPU que mejoran la eficiencia energética de las cargas de trabajo de E/S. Para ello consideramos dos problemas fundamentales en los procesadores modernos: el desequilibrio térmico que causa variablidad de rendimiento y el uso ineficiente de los recursos de la CPU durante cargas de trabajo de E/S. Además desarrollamos nuevas técnicas que optimizan la eficiencia energética a través de la coordinación entre las distintas capas del sistema operativo que gestionan CPU y la E/S. En tercer lugar, también centramos este trabajo en la optimización del intercambio de datos entre dominios virtuales. En nuestro trabajo nos referimos a esto como el intercambio de datos virtualizado, que se diferencia principalmente de las soluciones existentes mediante la coordinación de los flujos de datos mediante la cooperación entre distintos dominios virtuales. Para ello desarrollamos una solución de intercambio de datos que minimiza la copia de datos con el fin de reducir el movimiento de datos, e introducimos nuevas abstracciones y mecanismos para coordinar de manera más eficiente el almacenamiento de E/S en entornos virtuales.Programa Oficial de Doctorado en Ciencia y Tecnología InformáticaPresidente: Laurent Lefevre.- Vocal: Arturo González Escriban

    A comprehensive study of key Electric Vehicle (EV) components, technologies, challenges, impacts, and future direction of development

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    Abstract: Electric vehicles (EV), including Battery Electric Vehicle (BEV), Hybrid Electric Vehicle (HEV), Plug-in Hybrid Electric Vehicle (PHEV), Fuel Cell Electric Vehicle (FCEV), are becoming more commonplace in the transportation sector in recent times. As the present trend suggests, this mode of transport is likely to replace internal combustion engine (ICE) vehicles in the near future. Each of the main EV components has a number of technologies that are currently in use or can become prominent in the future. EVs can cause significant impacts on the environment, power system, and other related sectors. The present power system could face huge instabilities with enough EV penetration, but with proper management and coordination, EVs can be turned into a major contributor to the successful implementation of the smart grid concept. There are possibilities of immense environmental benefits as well, as the EVs can extensively reduce the greenhouse gas emissions produced by the transportation sector. However, there are some major obstacles for EVs to overcome before totally replacing ICE vehicles. This paper is focused on reviewing all the useful data available on EV configurations, battery energy sources, electrical machines, charging techniques, optimization techniques, impacts, trends, and possible directions of future developments. Its objective is to provide an overall picture of the current EV technology and ways of future development to assist in future researches in this sector

    Scorpion: Close Air Support (CAS) aircraft

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    The objective is to outline the results of the preliminary design of the Scorpion, a proposed close air support aircraft. The results obtained include complete preliminary analysis of the aircraft in the areas of aerodynamics, structures, avionics and electronics, stability and control, weight and balance, propulsion systems, and costs. A conventional wing, twin jet, twin-tail aircraft was chosen to maximize the desirable characteristics. The Scorpion will feature low speed maneuverability, high survivability, low cost, and low maintenance. The life cycle cost per aircraft will be 17.5 million dollars. The maximum takeoff weight will be 52,760 pounds. Wing loading will be 90 psf. The thrust to weight will be 0.6 lbs/lb. This aircraft meets the specified mission requirements. Some modifications have been suggested to further optimize the design

    An efficient drive, sensing, and actuation system using PZT stack actuator cells

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    Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering; and, (S.M.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2012.Cataloged from PDF version of thesis.Includes bibliographical references (p. 81-82).The PZT cellular actuator developed in the MIT d'Arbeloff Laboratory utilizes small-strain, high-force PZT stack actuators in a mechanical flexure system to produce a larger-strain, lower-force actuator useful in robotic systems. Many functionalities for these cellular actuators are developed which can have great impact on robotic systems and actuation itself. After initial exploration into other possible circuitry, a circuit is designed to recovery unused energy for the PZT cells. The circuit design is formed around a proposed method of distributed actuation using PZT cells which imposes that different PZT cells will be activated during different periods such that the charge from some cells can be transferred to others. If the application allows actuation which can conform to this criteria, the developed circuit can be used which, without optimization, can save ~41% of the energy used to drive the actuators with a theoretical upper limit on energy efficiency of 100%. A dynamic system consisting of multiple PZT actuators driving a linear gear is analyzed and simulated which can achieve a no load speed 2.4 m/s with minimal actuators. Then, the two-way transforming properties of PZT stack actuators are utilized to allow dual sensing and actuation. This method uses an inactive PZT cell as a sensor. With no additional sensors, a pendulum system driven by antagonistic groups of PZT cells is shown to find its own resonance with no system model. These functionalities of charge recovery, distributed actuation, and dual sensing and actuation set the PZT cellular actuator as an important contribution to robotic actuation and begin to illuminate the possible impacts of the concept. The design and analysis described reveals many possibilities for future applications and developments using the PZT cellular actuator in the fields of actuation and robotics.by Patrick R. BarragánS.M

    Robust Accelerating Control for Consistent Node Dynamics in a Platoon of CAVs

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    Driving as a platoon has potential to significantly benefit traffic capacity and safety. To generate more identical dynamics of nodes for a platoon of automated connected vehicles (CAVs), this chapter presents a robust acceleration controller using a multiple model control structure. The large uncertainties of node dynamics are divided into small ones using multiple uncertain models, and accordingly multiple robust controllers are designed. According to the errors between current node and multiple models, a scheduling logic is proposed, which automatically selects the most appropriate candidate controller into loop. Even under relatively large plant uncertainties, this method can offer consistent and approximately linear dynamics, which simplifies the synthesis of upper level platoon controller. This method is validated by comparative simulations with a sliding model controller and a fixed H∞ controller

    Volume 1 – Symposium

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    We are pleased to present the conference proceedings for the 12th edition of the International Fluid Power Conference (IFK). The IFK is one of the world’s most significant scientific conferences on fluid power control technology and systems. It offers a common platform for the presentation and discussion of trends and innovations to manufacturers, users and scientists. The Chair of Fluid-Mechatronic Systems at the TU Dresden is organizing and hosting the IFK for the sixth time. Supporting hosts are the Fluid Power Association of the German Engineering Federation (VDMA), Dresdner Verein zur Förderung der Fluidtechnik e. V. (DVF) and GWT-TUD GmbH. The organization and the conference location alternates every two years between the Chair of Fluid-Mechatronic Systems in Dresden and the Institute for Fluid Power Drives and Systems in Aachen. The symposium on the first day is dedicated to presentations focused on methodology and fundamental research. The two following conference days offer a wide variety of application and technology orientated papers about the latest state of the art in fluid power. It is this combination that makes the IFK a unique and excellent forum for the exchange of academic research and industrial application experience. A simultaneously ongoing exhibition offers the possibility to get product information and to have individual talks with manufacturers. The theme of the 12th IFK is “Fluid Power – Future Technology”, covering topics that enable the development of 5G-ready, cost-efficient and demand-driven structures, as well as individual decentralized drives. Another topic is the real-time data exchange that allows the application of numerous predictive maintenance strategies, which will significantly increase the availability of fluid power systems and their elements and ensure their improved lifetime performance. We create an atmosphere for casual exchange by offering a vast frame and cultural program. This includes a get-together, a conference banquet, laboratory festivities and some physical activities such as jogging in Dresden’s old town.:Group A: Materials Group B: System design & integration Group C: Novel system solutions Group D: Additive manufacturing Group E: Components Group F: Intelligent control Group G: Fluids Group H | K: Pumps Group I | L: Mobile applications Group J: Fundamental

    Manufacturing and testing of spline geometry using carbon fiber reinforced composite

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    2016 Fall.Includes bibliographical references.A model and manufacturing process for the design of carbon fiber reinforced composite spline shafts is developed and validated to investigate the feasibility of using composite splines for use in power transmission applications. Composite torque tubes for power transmission have been employed in various industries for over three decades and have shown up to a 50% mass decrease compared to steel shafts designed for the same use. One limiting factor for the amount of weight reduction achievable is the mechanism used to transfer power to and from the composite tube. Most composite shafts use adhesive bonding, fasteners, press fits, or some combination to join a steel or aluminum yolk or spline to the end of the tube. This research will investigate the feasibility of eliminating these mechanisms by replacing them by molding in splines to the composite torque tube. This will additionally reduce part count and manufacturing time as well as eliminating the heavy metal inserts. To achieve this, an analytical model is developed to investigate the strength of composite spline teeth of involute geometry as well as a composite torque tube. Due to the complex nature of designing with composites these models are supplemented by material models using a composite software package and finite element models (FEM). The involute splined shaft was then manufactured using an iterative approach to refine the sample quality and tested in torsion to failure. Although the peak failure torque had a large range over the samples it can be concluded that with improvements in the manufacturing process using molded composite splines is a feasible method of torque transfer. This can be concluded from the failure modes of the splined shaft as they indicate that the splines were able to adequately transfer the load to the torque tube
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