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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
81

Projeto e desenvolvimento de um sistema de controle para permitir a dirigibilidade de um veículo por meio do acionamento de um joystick. / Project and development of a control system to allow the handling of a vehicle by pushing a joystick.

Vieira Netto Junior, Arthur 06 July 2012 (has links)
Este trabalho visa o desenvolvimento de um sistema de controle, para permitir a dirigibilidade de um veículo automotor, por meio do acionamento de um joystick por um usuário, que substitui o volante e os pedais do acelerador e do freio. Foi construída uma placa de controle, que recebe os sinais de controle tais como esterçamento, aceleração e frenagem vindos do joystick operado pelo usuário, processa esses sinais e aciona eletronicamente os atuadores mecânicos no volante da direção, no servo freio e no acelerador, permitindo o controle dinâmico do veículo. Para testar esse sistema de controle foi desenvolvido um simulador de dinâmica veicular, que fornece em tempo real, as respostas dinâmicas de um veículo quando solicitado pelo usuário, por meio de comandos de direção, aceleração e frenagem. Associada ao referido simulador foi desenvolvida uma bancada de testes, que inclui os atuadores mecânicos, sensores, placa de controle e o joystick, que são testados em tempo real por um usuário, dirigindo um veículo com o auxílio do simulador em uma estrada virtual, realizando manobras como curvas, acelerações e frenagens variadas. Durante os testes mencionados foi encontrada uma série de falhas, que comprometiam a segurança e a dirigibilidade do veículo. Com base nessas falhas foi construída uma árvore de falhas, para o sistema proposto, cuja falha principal era a perda da dirigibilidade do veículo. Partindo da análise qualitativa da árvore de falhas foi proposta uma série de ações corretivas, visando manter o sistema no âmbito da dirigibilidade segura, para o usuário. Finalmente, uma proposta de um protocolo de segurança, para desenvolvimento de sistemas drive-by-wire é sugerida tendo como base o desenvolvimento deste trabalho. / This work aims the development of a control system, to allow the handling of a automotive vehicle, by moving a joystick, which replaces the steering wheel, accelerator and braking pedals and is operated by a user. An electronic control board was built to receive control signals, such as steering, acceleration and braking signals, using a joystick handled by a user. It converts those signals and activates the mechanical actuators in the steering wheel, brake booster and accelerator, to allow the dynamic control of the vehicle. To test that control system, it was developed a vehicle dynamics simulator, which provides, in real time, the dynamics responses of a vehicle when driven by a user, by steering, braking and accelerating commands. Together with the simulator it was developed a test bench, with mechanical actuators, sensors, a control board and a joystick, which were tested in real time, by a user driving a vehicle with the assistance of the simulator, on a virtual road, performing maneuvers like curves, accelerations and varied braking. During the test it was found a series of faults, which affected the safety and driveability of the vehicle. Based on these faults, it was built a fault tree, to the proposed system, whose main fault was the loss of driveability of the vehicle. Based on the qualitative analysis of the fault tree, it was proposed a series of corrective actions, in order to keep the system on scope of the safe driveability. Finally, a proposal for a safety protocol for drive-by-wire systems was made, based on the development of this work.
82

Predeterminantes de sobrevivência em vítimas de acidentes de trânsito submetidas a atendimento pré-hospitalar de suporte avançado à vida / Survival determinant factors in motor vehicle crash victms submitted to prehospital advanced life support

Malvestio, Marisa Aparecida Amaro 15 December 2005 (has links)
O Atendimento Pré Hospitalar (APH) é um importante recurso no atendimento à vítimas de trauma. No entanto, há muitas dificuldades para demonstrar o efeito benéfico das intervenções do APH na sobrevivência das vítimas, sobretudo as de suporte avançado à vida (SAV). A proposta deste estudo é caracterizar as vítimas de acidentes trânsito, com Revised Trauma Score (RTS) <11, atendidas pelo SAV municipal e encaminhadas a hospitais terciários em São Paulo, além de identificar as variáveis da fase pré-hospitalar associadas à sobrevivência e avaliar o valor predeterminante dessas variáveis sobre o resultado obtido pelas vítimas. As variáveis avaliadas foram: sexo, idade, mecanismos do acidente, procedimentos de suporte básico e SAV realizados, repercussão fisiológica do trauma na cena do acidente, (considerando o RTS , seus parâmetros e flutuações), o tempo consumido no APH, gravidade do trauma segundo o Injury Severity Score (ISS),a Maximum Abbreviated Injury Scale (MAIS) e número de lesões para cada segmento corporal. Os resultados obtidos por 175 vítimas entre 12 e 65 anos, foram submetidos a "Análise de Sobrevivência de Kaplan Meier" e ao “Modelo de Riscos Proporcionais de Cox". A variável dependente foi o tempo de sobrevivência após o acidente, considerando os intervalos até 6h,12h, 24h, 48h, até 7 dias e até o término da internação. Os homens (86,9%) e a faixa etária de 20 a 29 anos (36,0%) foram as mais freqüentes. Os atropelamentos (45,1%) e o envolvimento de motocicletas e seus ocupantes (30,9%) foram os destaques dentre os mecanismos de trauma. A média do RTS na cena e do ISS, foram respectivamente 8,8 e 19,4.Os segmentos corpóreos mais atingidos foram: cabeça (58,8%), membros inferiores (45,1%) e superfície externa (40%). A média de tempo consumido na fase de APH foi 41min (tempo de cena 20,2min). Ocorreram 36% de óbitos, (metade em até 6 horas). A análise estatística revelou 24 fatores associados à sobrevivência, dentre eles, os procedimentos respiratórios avançados e os circulatórios básicos, as variáveis relativas ao RTS e a gravidade (ISS, MAIS e o número de lesões). No modelo final de Cox, ter sido submetido a procedimentos respiratórios avançados, compressões torácicas, apresentar lesão abdominal e ISS>25, foi associado a maior risco para o óbito até 48h após o trauma. Até 7 dias, a compressão torácica não se manteve no modelo final e a PAS de zero a 75mmHg apresentou associação com a morte após o acidente. Até a alta hospitalar, a ausência de PAS na avaliação inicial permaneceu no modelo. A reposição de volume foi o único fator com valor protetor para o risco de óbito presente em todos os momentos / The prehospital care (PH) is an important resource to trauma victims’ care. Nevertheless, there is great difficulty in demonstrating the PH intervention’s positive effect in victim’s survival, especially when concerning the advanced life support (ALS). The aim of this study is to characterize motor vehicle crash victims with Revised Trauma Score (RTS) <11 cared by municipal ALS and moved to tertiary hospitals in São Paulo in addition to identifying the prehospital variables associated to survival, and to evaluate their values as victim survival outcome determinant. The variables evaluated were: sex, age, trauma mechanism, basic life support and ALS procedures, physiological measures in the accident scene (considering the RTS, its parameters and fluctuations), the time consumed in PH phase, trauma severity by Injury Severity Score (ISS), the Maximum Abbreviated Injury Scale (MAIS) and number of lesions in each body region. The main results obtained by 175 victims between 12 e 65 years of age were submitted to the Kaplan Meier Survival Analysis and to Cox Proportional hazards Regression Analysis. The dependent variable was the survival time after the motor vehicle accident considering the intervals up to 6,12,24 and 48hs , up to 7 days and until the time of hospital discharge. Men (86,9%) and the 20 to 29 aged group (36%) were the most frequent. The pedestrians struck by car (45,1%) and the motorcycles (and their riders) (30,9%)were the highlight in trauma mechanisms. The RTS and the ISS average were 8,8 and 19,4 respectively. The more damaged body regions were head (58,8%), lower limbs (45,1%) and external surface (40%).The prehospital time average was 41 min (scene time 20,2min).Death rate was 36% (half of which up to 6hs).The statistical analysis revealed 24 survival associated factors. The ALS and the circulatory basic procedures, the RTS variables and the trauma severity (ISS,MAIS and number of lesions) were within them. In the final Cox Model were associated to higher risk of death up to 48hs after trauma: the submission to ALS respiratory procedures, chest compressions, the presence of abdominal injuries and ISS>25 .Until the 7th day the chest compression was not sustained in a final model and the systolic blood pressure (SBP) from zero to 75mmHg revealed statistical association with death after trauma. Until hospital discharge the SBP absence in scene evaluation remained in the model. The prehospital intravenous fluid refilling was the only factor of protector value to death risk in all moments
83

An intelligent vehicle security system based on human behaviors modeling.

January 2006 (has links)
by Meng Xiaoning. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2006. / Includes bibliographical references (leaves 99-106). / Abstracts in English and Chinese. / Chapter 1 --- Introduction --- p.1 / Chapter 1.1 --- Motivation --- p.1 / Chapter 1.2 --- Overview --- p.2 / Chapter 1.3 --- Organization of the Thesis --- p.3 / Chapter 2 --- Related Research --- p.6 / Chapter 2.1 --- Information Technology in Cars --- p.6 / Chapter 2.2 --- Anti-theft Protection --- p.8 / Chapter 2.3 --- Learning Human Behaviors --- p.10 / Chapter 2.4 --- Neural Network Learning --- p.11 / Chapter 3 --- Experimental Design --- p.14 / Chapter 3.1 --- Overview --- p.14 / Chapter 3.2 --- Driving Simulation Subsystem --- p.14 / Chapter 3.3 --- Data Sensing and Capturing Subsystem --- p.15 / Chapter 3.4 --- Data Analysis Subsystem --- p.17 / Chapter 4 --- Data Preprocessing for Feature Selection --- p.23 / Chapter 4.1 --- Introduction --- p.23 / Chapter 4.2 --- Fast Fourier Transform --- p.23 / Chapter 4.3 --- Principal Component Analysis --- p.24 / Chapter 4.4 --- Independent Component Analysis --- p.26 / Chapter 5 --- Classification via Support Vector Machine --- p.28 / Chapter 5.1 --- Introduction --- p.28 / Chapter 5.1.1 --- Why Using Support Vector Machine --- p.28 / Chapter 5.1.2 --- Mathematic Description --- p.29 / Chapter 5.2 --- Problem Formulation --- p.31 / Chapter 5.3 --- Approach --- p.31 / Chapter 5.4 --- Experimental Results --- p.34 / Chapter 5.4.1 --- Preprocess Data Analysis --- p.34 / Chapter 5.4.2 --- Models Design --- p.37 / Chapter 5.5 --- Discussion --- p.44 / Chapter 6 --- Evaluation via Hidden Markov Model --- p.47 / Chapter 6.1 --- Introduction --- p.47 / Chapter 6.1.1 --- Why Using Hidden Markov Model --- p.48 / Chapter 6.1.2 --- Mathematic Description --- p.50 / Chapter 6.2 --- Problem Formulation --- p.51 / Chapter 6.3 --- Approach --- p.53 / Chapter 6.4 --- Experimental Results --- p.56 / Chapter 6.4.1 --- Model-to-model Measure --- p.56 / Chapter 6.4.2 --- Human-to-model Measure --- p.63 / Chapter 6.4.3 --- Parameters Optimization --- p.66 / Chapter 6.5 --- Discussion --- p.69 / Chapter 7 --- System Design and Implementation --- p.71 / Chapter 7.1 --- Introduction --- p.71 / Chapter 7.2 --- Hardware --- p.72 / Chapter 7.3 --- Software --- p.78 / Chapter 7.4 --- System Demonstration --- p.80 / Chapter 8 --- Conclusion and Future Work --- p.82 / Chapter 8.1 --- Contributions --- p.82 / Chapter 8.2 --- Future Work --- p.84 / Chapter A --- Hidden Markov Model Training --- p.87 / Chapter A.1 --- Forward-backward Algorithm --- p.87 / Chapter A.2 --- Baum-Welch Algorithm --- p.87 / Chapter B --- Human Driving Behavior Data --- p.90 / Chapter C --- Publications Resulted from the Study --- p.98
84

Game theoretical modelling of a driver's interaction with active steering

Na, Xiaoxiang January 2014 (has links)
No description available.
85

The independent steering and driving vehicle: design, energy efficiency and parking analysis. / CUHK electronic theses & dissertations collection

January 2010 (has links)
After describing the development of the ISDV, this thesis studies the energy management which can improve the energy efficiency. It is shown that the traditional electric vehicle (EV) is not capable of managing the energy required for one driving cycle because it has only a single traction motor. This thesis proposes and examines a new way to manage electrical energy in which torque is distributed among different in-wheel motors to achieve a higher level of overall energy efficiency, which has been enhanced and demonstrated in various driving cycles. / Thereafter, the thesis studies two aspects of benefits the ISDV can bring to parking. One is in space efficiency, defined as the ratio of the total space occupied by the vehicle in its final parked state over the whole area covered by the parking lot. Comparison of the ISDV and traditional vehicles in parking proves that the ISDV afford a higher level of space efficiency. The other aspect is the parking time. It is tested experimentally in the hardware-in-loop (HIL) system, and the motions of traditional vehicles, the zero radius turning motion, and the free motion of the ISDV are compared. The less time for parking demonstrates the easiness to steer the ISDV. / Throughout the history of human civilization, vehicles have played a significant role by connecting people in various locations. They have thus boosted the progress of civilization and made our lives more convenient. However, as the number of vehicles on the road has increased, the convenience, which vehicles provide, has gradually turned into inconvenience in three respects: 1) the energy consumed by vehicles accounts for a large proportion of total energy consumption, which is in an ever-increasing trend; 2) more parking space is needed, a significant proportion of which is not for parking itself but for enabling the vehicle to be navigated to its final parking slot; 3) the effort required to park a car is also troublesome, causing the driver to spend much more time in a crowded parking lot. / To alleviate these three problems, I develop a methodology to design an independent steering and driving vehicle (ISDV). It brings together the robotic technologies of steer-by-wire, drive-by-wire, four-wheel-independent-steering, and four-wheel-independent-driving. All four wheels of the ISDV can be steered independently, so that vehicle rotation and translation can be decoupled from each other. Omni-directional motions such as zero radius turning (ZRT) and lateral parking (LP) are realized, thereby enhancing the agility of the vehicle. In contrast with omni-directional wheeled mobile robots, this vehicle is targeted at serving as a human carrier or even as a vehicle carrier in the future. / Qian, Huihuan. / Adviser: Yangsheng Xu. / Source: Dissertation Abstracts International, Volume: 73-03, Section: B, page: . / Thesis (Ph.D.)--Chinese University of Hong Kong, 2010. / Includes bibliographical references (leaves 149-159). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. [Ann Arbor, MI] : ProQuest Information and Learning, [201-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstract also in Chinese.
86

Understanding the Challenges of the Older Driver: Attention, Road Complexity and Assessment

Stinchcombe, Arne 05 December 2011 (has links)
Older adults are at an increased risk for motor-vehicle collisions (MVCs) once distance driven is considered, a finding that is partly attributed to a decline in attention related processes associated with age. MVCs typically occur in highly specific areas, suggesting a role of the complexity of the driving environment contributing to the occurrence of MVCs. The goal of this thesis was to explore the attentional demands of simulated driving events of varying complexity among young, mature and older drivers. In the present studies, attentional demand associated with driving was assessed through the peripheral detection task (PDT), a method in which a stimulus unrelated to the driving task is presented and drivers manually respond immediately upon its detection; latency to respond is recorded. The complexity of the driving environment was operationalized in terms of vehicle handling and of information processing elements. In the first study, inexperienced drivers completed a series simulated driving scenarios that varied according to their information processing and vehicle handling demands. The results showed a reduction in PDT performance at intersections where information processing is increased as well as when handling maneuvers behind a lead vehicle were required. Building on these findings, the second study employed the identical protocol as the first but examined differences in attentional demand between mid-aged and older drivers. The results indicated that when information processing demands were increased through the addition of traffic, and buildings, all participants exhibited greater workload regardless of age. The third study presented young, mid-aged, and older drivers with a simulated driving assessment course and administered several cognitive tasks. The results of the third study supported the hypothesis in that complex driving situations elicited greater attentional demand among drivers of all ages. Older adults showed greater attentional demand in comparison to young and mid-aged adults even after controlling for baseline response time. Older drivers also scored poorer on a global measure of driving safety. The results of this thesis highlight the roles of intrinsic and extrinsic factors involved in safe driving and are discussed in terms of appropriate interventions to improve road safety.
87

Understanding the Challenges of the Older Driver: Attention, Road Complexity and Assessment

Stinchcombe, Arne 05 December 2011 (has links)
Older adults are at an increased risk for motor-vehicle collisions (MVCs) once distance driven is considered, a finding that is partly attributed to a decline in attention related processes associated with age. MVCs typically occur in highly specific areas, suggesting a role of the complexity of the driving environment contributing to the occurrence of MVCs. The goal of this thesis was to explore the attentional demands of simulated driving events of varying complexity among young, mature and older drivers. In the present studies, attentional demand associated with driving was assessed through the peripheral detection task (PDT), a method in which a stimulus unrelated to the driving task is presented and drivers manually respond immediately upon its detection; latency to respond is recorded. The complexity of the driving environment was operationalized in terms of vehicle handling and of information processing elements. In the first study, inexperienced drivers completed a series simulated driving scenarios that varied according to their information processing and vehicle handling demands. The results showed a reduction in PDT performance at intersections where information processing is increased as well as when handling maneuvers behind a lead vehicle were required. Building on these findings, the second study employed the identical protocol as the first but examined differences in attentional demand between mid-aged and older drivers. The results indicated that when information processing demands were increased through the addition of traffic, and buildings, all participants exhibited greater workload regardless of age. The third study presented young, mid-aged, and older drivers with a simulated driving assessment course and administered several cognitive tasks. The results of the third study supported the hypothesis in that complex driving situations elicited greater attentional demand among drivers of all ages. Older adults showed greater attentional demand in comparison to young and mid-aged adults even after controlling for baseline response time. Older drivers also scored poorer on a global measure of driving safety. The results of this thesis highlight the roles of intrinsic and extrinsic factors involved in safe driving and are discussed in terms of appropriate interventions to improve road safety.
88

Analysis and Control of High-Speed Wheeled Vehicles

Velenis, Efstathios 29 March 2006 (has links)
In this work we reproduce driving techniques to mimic expert race drivers and obtain the open-loop control signals that may be used by auto-pilot agents driving autonomous ground wheeled vehicles. Race drivers operate their vehicles at the limits of the acceleration envelope. An accurate characterization of the acceleration capacity of the vehicle is required. Understanding and reproduction of such complex maneuvers also require a physics-based mathematical description of the vehicle dynamics. While most of the modeling issues of ground-vehicles/automobiles are already well established in the literature, lack of understanding of the physics associated with friction generation results in ad-hoc approaches to tire friction modeling. In this work we revisit this aspect of the overall vehicle modeling and develop a tire friction model that provides physical interpretation of the tire forces. The new model is free of those singularities at low vehicle speed and wheel angular rate that are inherent in the widely used empirical static models. In addition, the dynamic nature of the tire model proposed herein allows the study of dynamic effects such as transients and hysteresis. The trajectory-planning problem for an autonomous ground wheeled vehicle is formulated in an optimal control framework aiming to minimize the time of travel and maximize the use of the available acceleration capacity. The first approach to solve the optimal control problem is using numerical techniques. Numerical optimization allows incorporation of a vehicle model of high fidelity and generates realistic solutions. Such an optimization scheme provides an ideal platform to study the limit operation of the vehicle, which would not be possible via straightforward simulation. In this work we emphasize the importance of online applicability of the proposed methodologies. This underlines the need for optimal solutions that require little computational cost and are able to incorporate real, unpredictable environments. A semi-analytic methodology is developed to generate the optimal velocity profile for minimum time travel along a prescribed path. The semi-analytic nature ensures minimal computational cost while a receding horizon implementation allows application of the methodology in uncertain environments. Extensions to increase fidelity of the vehicle model are finally provided.
89

The effects of linguistic fluency on performance in a simulated cellular telephone and driving situation /

Telner, Jason A. January 2008 (has links)
Thesis (Ph.D.)--York University, 2008. Graduate Programme in Psychology. / Typescript. Includes bibliographical references (leaves 229-251). Also available on the Internet. MODE OF ACCESS via web browser by entering the following URL: http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&res_dat=xri:pqdiss&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&rft_dat=xri:pqdiss:NR46015
90

Applications of vehicle location and communication technology in fleet management systems /

Wong, Chi-tak, Keith. January 2001 (has links)
Thesis (M.A.)--University of Hong Kong, 2001. / Includes bibliographical references (leaf 62).

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