712 research outputs found

    Advanced flight control system study

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    The architecture, requirements, and system elements of an ultrareliable, advanced flight control system are described. The basic criteria are functional reliability of 10 to the minus 10 power/hour of flight and only 6 month scheduled maintenance. A distributed system architecture is described, including a multiplexed communication system, reliable bus controller, the use of skewed sensor arrays, and actuator interfaces. Test bed and flight evaluation program are proposed

    Definition of avionics concepts for a heavy lift cargo vehicle. Volume 1: Executive summary

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    A cost effective, multiuser simulation, test, and demonstration facility to support the development of avionics systems for future space vehicles is examined. The technology needs and requirements of future Heavy Lift Cargo Vehicles (HLCVs) are analyzed and serve as the basis for sizing of the avionics facility, although the lab is not limited in use to support of HLCVs. Volume 1 provides a summary of the vehicle avionics trade studies, the avionics lab objectives, a summary of the lab's functional requirements and design, physical facility considerations, and cost estimates

    Performance measurement and evaluation of time-shared operating systems

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    Time-shared, virtual memory systems are very complex and changes in their performance may be caused by many factors - by variations in the workload as well as changes in system configuration. The evaluation of these systems can thus best be carried out by linking results obtained from a planned programme of measurements, taken on the system, to some model of it. Such a programme of measurements is best carried out under conditions in which all the parameters likely to affect the system's performance are reproducible, and under the control of the experimenter. In order that this be possible the workload used must be simulated and presented to the target system through some form of automatic workload driver. A case study of such a methodology is presented in which the system (in this case the Edinburgh Multi-Access System) is monitored during a controlled experiment (designed and analysed using standard techniques in common use in many other branches of experimental science) and the results so obtained used to calibrate and validate a simple simulation model of the system. This model is then used in further investigation of the effect of certain system parameters upon the system performance. The factors covered by this exercise include the effect of varying: main memory size, process loading algorithm and secondary memory characteristics

    Innovative actuator fault identification based on back electromotive force reconstruction

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    The ever increasing adoption of electrical power as secondary form of on-board power is leading to an increase in the usage of electromechanical actuators (EMAs). Thus, in order to maintain an acceptable level of safety and reliability, innovative prognostics and diagnostics methodologies are needed to prevent performance degradation and/or faults propagation. Furthermore, the use of effective prognostics methodologies carries several benefits, including improved maintenance schedule capability and relative cost decrease, better knowledge of systems health status and performance estimation. In this work, a novel, real-time approach to EMAs prognostics is proposed. The reconstructed back electromotive force (back-EMF), determined using a virtual sensor approach, is sampled and then used to train an artificial neural network (ANN) in order to evaluate the current system status and to detect possible coils partial shorts and rotor imbalances

    Eco-Layouts in Water Distribution Systems

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    [EN] To achieve maximum efficiency in water pressurized transport, it is necessary to perform a global analysis, whenever possible starting from the system's conception. The first stage of the process is the network layout, the main topic of this paper. The optimum topology from an energy point of view (or eco-layout) is the one that, insofar as is feasible, allows equalizing the network's pressure to the set pressure standards. Eco-layouts can be easily designed in new systems but are difficult to implement, mainly in the short term, in operating networks. Nevertheless, because no system is eternal, the required actions can be gradually implemented. Therefore, the main goal of this paper is to identify and discuss these guidelines and actions, some of which are apparently contradictory to current design criteria, whereas others endorse modern management trends. These strategies can be summarized in two points: (1)providing lower pressure to consumers saves energy, and (2)setting up smaller pressure zones in terms of the elevation steps between zones will enable water companies to supply water at lower pressure in hilly areas. In the end, networks with more-efficient layouts can achieve important energy savings. (C) 2018 American Society of Civil Engineers.The authors acknowledge the valuable contributions made by the reviewers of this paper, because their comments and suggestions helped to significantly improve the contents. Additionally, the authors thank Omnium Iberico/Aguas de Valencia for partially funding this research, and particularly its Energy Efficiency Department for providing some real case studies which inspired some of the examples included in this paper.Cabrera Marcet, E.; Gomez Selles, E.; Soriano Olivares, J.; Del Teso-March, R. (2019). Eco-Layouts in Water Distribution Systems. Journal of Water Resources Planning and Management. 145(1):1-11. https://doi.org/10.1061/(ASCE)WR.1943-5452-0001024111145

    Framework for Electric Vehicles and Photovoltaic Synergies

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    Historically road transport has been exclusively dominated by petrol and diesel engines. Both alternatives are proved to be unsustainable due to their environmental impacts and the limited nature of their primary resources. Today’s transportation sector in the European Union (EU) accounts for 23% of CO2 emissions, 72% of which is being emitted by road transport. The European Union’s CO2 emission regulation for new cars, has come as a response to set emission performance limits for new passenger cars with the goal of establishing a road map change for automotive sector. Furthermore, the EU has set challenging targets to reduce greenhouse gas emissions by 40% in 2030 (relative to emissions in 1990) and for energy consumed to be generated at least with 27% from renewable sources in 2030. As regards energy efficiency, the 2030 framework also indicated that the cost-effective delivery of the greenhouse gas emissions reduction target for 2030 would require increased energy savings of the order of 27%. The renewable energy directive particularly identified: technological innovation, energy efficiency and contribution of renewable energy sources in transport sector as one of the most effective tools in reaching the expected targets in terms of sustainability and security of the supply. In such context it is obvious that reaching these challenges will be certainly depending on the rollout of Electric Vehicles (EV) as a mean of sustainable transport, higher penetration of distributed renewable energy sources. One consequential challenge will consist in accommodating such paradigm in the most cost-efficient fashion through active involvement of customer and better flexibility of the demand. This report highlights the current trends and expected evolution in the EU in term of electromobility, Photovoltaic (PV) systems and smart grids, with the aim of identifying mutual synergies aiming at enabling: energy efficiency, sustainable transport and higher share of renewable energy sources in the final energy mix. A technical conceptual architecture for integration of EV facilities and distributed generation sources in the context of smart grid is proposed to identify the predictable penetration limits of PV systems and EV users.JRC.F.3-Energy Security, Systems and Marke

    An authorisation framework for actively controlled running gear

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    A Shift2Rail funded research project called RUN2Rail has investigated a range of new technologies for railway rolling stock. The project included a task on the use of active suspensions, and one of the subtasks was to propose a strategy supporting the authorisation by safety authorities for highly innovative mechatronic vehicles to be placed on the market. The incorporation of electronics and control into suspension systems is still at an early stage, so this paper provides a framework for a practical and efficient authorisation strategy, primarily based upon existing European regulations and standards but in general applicable worldwide
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