The space station tethered elevator system

The optimized conceptual engineering design of a space station tethered elevator is presented. The elevator is an unmanned mobile structure which operates on a ten kilometer tether spanning the distance between the Space Station and a tethered platform. Elevator capabilities include providing access to residual gravity levels, remote servicing, and transportation to any point along a tether. The potential uses, parameters, and evolution of the spacecraft design are discussed. Engineering development of the tethered elevator is the result of work conducted in the following areas: structural configurations; robotics, drive mechanisms; and power generation and transmission systems. The structural configuration of the elevator is presented. The structure supports, houses, and protects all systems on board the elevator. The implementation of robotics on board the elevator is discussed. Elevator robotics allow for the deployment, retrieval, and manipulation of tethered objects. Robotic manipulators also aid in hooking the elevator on a tether. Critical to the operation of the tethered elevator is the design of its drive mechanisms, which are discussed. Two drivers, located internal to the elevator, propel the vehicle along a tether. These modular components consist of endless toothed belts, shunt-wound motors, regenerative power braking, and computer controlled linear actuators. The designs of self-sufficient power generation and transmission systems are reviewed. Thorough research indicates all components of the elevator will operate under power provided by fuel cells. The fuel cell systems will power the vehicle at seven kilowatts continuously and twelve kilowatts maximally. A set of secondary fuel cells provides redundancy in the unlikely event of a primary system failure. Power storage exists in the form of Nickel-Hydrogen batteries capable of powering the elevator under maximum loads

Advanced Rotorcraft Transmission (ART) program

Work performed by the McDonnell Douglas Helicopter Company and Lucas Western, Inc. within the U.S. Army/NASA Advanced Rotorcraft Transmission (ART) Program is summarized. The design of a 5000 horsepower transmission for a next generation advanced attack helicopter is described. Government goals for the program were to define technology and detail design the ART to meet, as a minimum, a weight reduction of 25 percent, an internal noise reduction of 10 dB plus a mean-time-between-removal (MTBR) of 5000 hours compared to a state-of-the-art baseline transmission. The split-torque transmission developed using face gears achieved a 40 percent weight reduction, a 9.6 dB noise reduction and a 5270 hour MTBR in meeting or exceeding the above goals. Aircraft mission performance and cost improvements resulting from installation of the ART would include a 17 to 22 percent improvement in loss-exchange ratio during combat, a 22 percent improvement in mean-time-between-failure, a transmission acquisition cost savings of 23 percent of $165K, per unit, and an average transmission direct operating cost savings of 33 percent, or$24K per flight hour. Face gear tests performed successfully at NASA Lewis are summarized. Also, program results of advanced material tooth scoring tests, single tooth bending tests, Charpy impact energy tests, compact tension fracture toughness tests and tensile strength tests are summarized

Preliminary power train design for a state-of-the-art electric vehicle

Power train designs which can be implemented within the current state-of-the-art were identified by means of a review of existing electric vehicles and suitable off-the-shelf components. The affect of various motor/transmission combinations on vehicle range over the SAE J227a schedule D cycle was evaluated. The selected, state-of-the-art power train employs a dc series wound motor, SCR controller, variable speed transmission, regenerative braking, drum brakes and radial ply tires. Vehicle range over the SAE cycle can be extended by approximately 20% by the further development of separately excited, shunt wound DC motors and electrical controllers. Approaches which could improve overall power train efficiency, such as AC motor systems, are identified. However, future emphasis should remain on batteries, tires and lightweight structures if substantial range improvements are to be achieved

An object-oriented modelling method for evolving the hybrid vehicle design space in a systems engineering environment

A combination of environmental awareness, consumer demands and pressure from legislators has led automotive manufacturers to seek for more environmentally friendly alternatives while still meeting the quality, performance and price demands of their customers. This has led to many complex powertrain designs being developed in order to produce vehicles with reduced carbon emissions. In particular, within the last decade most of the major automotive manufactures have either developed or announced plans to develop one or more hybrid vehicle models. This means that to be competitive and o er the best HEV solutions to customers, manufacturers have to assess a multitude of complex design choices in the most e cient way possible. Even though the automotive industry is adept at dealing with the many complexities of modern vehicle development; the magnitude of design choices, the cross coupling of multiple domains, the evolving technologies and the relative lack of experience with respect to conventional vehicle development compounds the complexities within the HEV design space. In order to meet the needs of e cient and exible HEV powertrain modelling within this design space, a parallel is drawn with the development of complex software systems. This parallel is both from a programmatic viewpoint where object-oriented techniques can be used for physical model development with new equation oriented modelling environments, and from a systems methodology perspective where the development approach encourages incremental development in order to minimize risk. This Thesis proposes a modelling method that makes use of these new tools to apply OOM principles to the design and development of HEV powertrain models. Furthermore, it is argued that together with an appropriate systems engineering approach within which the model development activities will occur, the proposed method can provide a more exible and manageable manner of exploring the HEV design space.The exibility of the modelling method is shown by means of two separate case studies, where a hierarchical library of extendable and replaceable models is developed in order to model the di erent powertrains. Ultimately the proposed method leads to an intuitive manner of developing a complex system model through abstraction and incremental development of the abstracted subsystems. Having said this, the correct management of such an e ort within the automotive industry is key for ensuring the reusability of models through enforced procedures for structuring, maintaining, controlling, documenting and protecting the model development. Further, in order to integrate the new methodology into the existing systems and practices it is imperative to develop an e cient means of sharing information between all stakeholders involved. In this respect it is proposed that together with an overall systems modelling activity for tracking stakeholder involvement and providing a central point for sharing data, CAE methods can be employed in order to automate the integration of data.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Contribution to the validation and verification of drive-neutral-reverse subsystem of a CVT transmission

Continuously Variable Transmissions (CVT) are the synonymous for fuel economy and smooth ride. Due to these major features of this type of automatic transmission (AT) it can be easily the future of automatic transmissions since the restrictions regarding to the fuel emissions are getting stricter. The knowledge by the student related to this thematic was developed in an internship with a duration of six months at a specialized company in the development and production of CVT transmissions. By being incorporated in the department of R&D, specifically on the team of the DNR subsystem (Drive‐Neutral‐Reverse subsystem), it was possible to be introduced to CVT. Punch Powertrain NV in Belgium, Sint‐Truiden, was the perfect opportunity to enrich the academic experience of the student, to introduce the student to development field of automotive transmissions industry from concept to testing and also to consolidate the experience in the automotive industry previously started at Simoldes Plásticos during the master degree. Firstly, it was suggested to assist to the prototype assembly process of a complete CVT followed by the analyses to the flow chart of the DNR subsystem and the manufacturability of all the components of the subsystem in order to get introduced to the subsystem. Secondly it was proposed to develop a showcase model which would be a great tool to explain people the working principle of a DNR subsystem in detail. At the same time, the student decided to start some calculations related to the DNR subsystem not only to better understand the subsystem and apply the knowledge obtained during the graduation but also to learn more specific subjects related to this field of study. This task would later allow the student to verify the mechanical requirements. After asking for quotations and getting in contact with several suppliers it was time to assemble the entire showcase getting in contact with different manufacturing processes and difficulties. At the end, it is irrefutable the amount of knowledge acquired during the internship. Undoubtedly, the support from all the colleagues was very important by transmitting me all their knowledge and experience.Transmissões Continuamente Variáveis (CVT) são sinónimo de economia de combustível e condução suave. Devido a estas grandes características deste tipo de transmissão, podemos estar facilmente perante o futuro das transmissões automáticas visto que as restrições relativamente às emissões de combustível se estão a tornar mais apertadas. O conhecimento adquirido pelo estudante nesta temática foi desenvolvido num estágio com duração de seis meses numa empresa especializada no desenvolvimento e produção de transmissões CVT. Ao estar incorporado no departamento de I&D, mais especificamente na equipa de desenvolvimento do subsistema DNR, foi possível familiarizar‐se com as Transmissões de Continuamente Variáveis. Punch Powertrain NV na Bélgica, Sint‐Truiden, foi a oportunidade perfeita para enriquecer a experiência do estudante, introduzi‐lo à área de desenvolvimento da indústria das transmissões automóveis desde o conceito até à fase de testes, e também para consolidar a experiência na indústria automóvel previamente iniciada num estágio na Simoldes Plásticos durante o percurso de mestrado. Em primeiro lugar, foi sugerido assistir à montagem da fase protótipo de uma CVT seguida da análise do esquema do fluxo do óleo do subsistema DNR e os processos de fabrico de todos os componentes do subsistema com vista a integrar‐se no subsistema. Em segundo lugar foi proposto desenvolver um equipamento de amostra que seria uma ótima ferramenta para explicar detalhadamente às pessoas o princípio de funcionamento de um subsistema DNR. Ao mesmo tempo, o estudante decidiu começar alguns cálculos relativos ao subsistema DNR não só para melhor compreender o subsistema, mas também para aplicar o conhecimento adquirido durante o seu percurso académico com vista a aprender campos mais específicos sobre este tema de estudo. Esta tarefa iria mais tarde permitir ao estudante a verificação dos requisitos. Após de alguns pedidos de orçamentação e de ter entrado em contacto com alguns fornecedores, era tempo da montagem do equipamento de amostra estando diretamente em contacto com diferentes processos de fabrico e respetivas dificuldades. No final, é irrefutável a proporção de conhecimento adquirido durante este estágio. Sem dúvida alguma o apoio dos colegas foi bastante importante ao transmitirem todo o seu conhecimento e experiência

A Systematic Approach to Human Powered Vehicle Design with an Emphasis on Providing Guidelines for Mentoring Students

The objective of this research is to provide guidebook that approaches the design of a human powered vehicle (HPV) from a systematic view for an ASME competition. The guidebook introduces students to design and enhances their current understanding related to design, general engineering principals, and engineering principals specific to HPVs. In terms of the design process a combination between the traditional design process and the systems engineering design process is discussed. From here the design process in broken into six main sections for the guidebook, and an evaluation section used to emphasis the usefulness of the guidebook. First an overall view of the traditional and system engineering design processes are given, along with an overview of the human powered vehicle competition (HPVC). This is followed by details of project planning and problem development. Next the conceptual stage is introduced where concept generation and evaluation methods and examples are discussed. Embodiment design is given in the following section, where solution variants are modeled in a preliminary layout. Next, methods of how to create a more defined preliminary layout are given in the detail design section were a definitive layout is established. Finally prototyping, testing, redesigns, and final design recommendations are outlined in the last section. In addition, the guidebook provided is meant to serve as a method that can be used to mentor students in the design process of an HPV. As such, the guidebook has been developed through a literature review of design theories, managerial, organizational, and engineering practices that have had beneficial impacts, and past experiences with designing HPVs. In terms of past experiences, the interactions with students involved in a creative inquiry at Clemson University have used as a subjective means to outline some of the important design considerations needed to be discussed. Additionally, Clemson\u27s HPVs have primarily consisted of tadpole tricycles and as such, a more in depth analysis is included for this particular HPV style

非線形弾性要素による内部力補償に基づく無段階変位–力変換機構の創生 ― 微小操作力で強大な磁気力・把持力・制動力・張力を制御可能とするロボット要素 ―

Tohoku University博士（情報科学）thesi

Index to 1986 NASA Tech Briefs, volume 11, numbers 1-4

Short announcements of new technology derived from the R&D activities of NASA are presented. These briefs emphasize information considered likely to be transferrable across industrial, regional, or disciplinary lines and are issued to encourage commercial application. This index for 1986 Tech Briefs contains abstracts and four indexes: subject, personal author, originating center, and Tech Brief Number. The following areas are covered: electronic components and circuits, electronic systems, physical sciences, materials, life sciences, mechanics, machinery, fabrication technology, and mathematics and information sciences

New trends in electrical vehicle powertrains

The electric vehicle and plug-in hybrid electric vehicle play a fundamental role in the forthcoming new paradigms of mobility and energy models. The electrification of the transport sector would lead to advantages in terms of energy efficiency and reduction of greenhouse gas emissions, but would also be a great opportunity for the introduction of renewable sources in the electricity sector. The chapters in this book show a diversity of current and new developments in the electrification of the transport sector seen from the electric vehicle point of view: first, the related technologies with design, control and supervision, second, the powertrain electric motor efficiency and reliability and, third, the deployment issues regarding renewable sources integration and charging facilities. This is precisely the purpose of this book, that is, to contribute to the literature about current research and development activities related to new trends in electric vehicle power trains.Peer ReviewedPostprint (author's final draft