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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.
41

Stratégie intelligente de gestion du système énergétique global d’un véhicule hybride / Smart strategy of an hybrid vehicle global energetic system gestion

Joud, Loïc 07 November 2018 (has links)
L’objectif principal de ce travail est de développer une stratégie de gestion optimale afin d’améliorer l’efficacité énergétique des véhicules hybrides. Ces travaux comportent une partie analyse expérimentale de la mobilité, une partie modélisation numérique et une partie optimisation de la stratégie de gestion énergétique. L’étude de la mobilité a permis de mettre en avant et de quantifier la prédictibilité des trajets, dus à une forte mobilité contrainte. La modélisation dynamique du véhicule, nécessaire à l’étude de stratégie, a été réalisée par Représentation Energétique Macroscopique (REM) qui est une bonne méthode pour ce type d’étude. La stratégie proposée est basée sur le contrôle prédictif (MPC), résolu par une méthode de Programmation Quadratique, et mis en place en s’appuyant sur la prédiction de cycle issu de l’étude expérimentale. Les perspectives d’améliorations de ces travaux se situent au niveau de la consolidation de la base de données, et du niveau de modélisation de la batterie (impact de la thermique et du vieillissement) et du moteur thermique (prise en compte des polluants). / The main objective of this work is to develop an optimal management strategy to improve energetic efficiency of hybrid electric vehicle. This work is composed by a mobility experimental analysis part, a numerical modelization part and an optimization part of the energy management strategy. The study of mobility allow to highligth and quantify the predictibility of trips, due to a constraint mobility.The dynamic modelling of the vehicle which is necesary to study perfomance of strategies, was realized by Energetic Macroscopic Representation (EMR) which is a good methode in this case. The proposed strategy is based on the predictive control (MPC), solve by a method of Programming Quadratic, and set up resting on the cycle prediction determined from the experimental study. The perspectives of improvements of these work are consolidation of the database, and improvement of the battery modelling (imcluding thermal and ageing effects) and of the thermal engine (taken into account by some pollutants).
42

U.S. National Drug Control Strategy & the Andean Initiative Roots of Failure

Davis, Jonathon Scott 12 1900 (has links)
This thesis examines the reason for the failure of the U.S. National Drug Control Strategy, and the Andean Initiative. Its scope is limited to cocaine trafficking from the Andean nations of Bolivia, Colombia, and Peru, to the United States. It provides the background of those strategies, and analyzes various explanations for failure. Based on this analysis, the thesis provides policy recommendations for antidrug efforts, which include increased emphasis on demand-related issues, judicial system consistency and harsher penalties, improvement in domestic and international coordination, and expanded restrictions on U.S. government agencies conducting covert operations. In conclusion, this thesis proposes that any real solution to the drug problem lies not with supply interdiction, and not with expanded foreign assistance, targeting user accountability in the United States.
43

Modelagem, controle e otimização de consumo de combustível para um veículo híbrido elétrico série-paralelo. / Modeling, control and application of dynamic programming to a series-parallel hydrid electric vehicle.

Ivan Miguel Trindade 16 May 2016 (has links)
O principal objetivo dos veículos híbridos é diminuir o consumo de combustível em relação a veículos convencionais. Para isso, existe a necessidade de realizar a integração dos diferentes sistemas do trem-de-força e coordenar o seu funcionamento através de estratégias de controle. Tais estratégias são desenvolvidas e simuladas em conjunto com um modelo computacional da planta do veículo antes de serem aplicadas em uma unidade de controle eletrônica. O presente estudo tem como objetivo analisar o gerenciamento de energia em um veículo híbrido elétrico não-plugin do tipo série-paralelo visando à diminuição de consumo de combustível. O método de otimização global é utilizado para encontrar as variáveis de controle que resultam no mínimo consumo de combustível em um determinado ciclo de condução. Na primeira etapa, um modelo computacional da planta do veículo e da estratégia de controle não-ótima são criados. Os resultados obtidos da simulação são então comparados com dados experimentais do veículo operando em dinamômetro de chassis. A seguir, o método de otimização global é aplicado ao modelo computacional utilizando programação dinâmica e tendo como objetivo a minimização do consumo de combustível total ao final do ciclo. Os resultados mostram considerável redução do consumo de combustível utilizando otimização global e tendo como variável de controle não só a razão de distribuição de torque mas também os pontos de operação do motor de combustão. Os modelos computacionais criados nesse trabalho são disponibilizados e podem ser usados para o estudo de diferentes estratégias de controle para veículos híbridos. / The main goal of hybrid electric vehicles is to decrease engine emission and fuel consumption levels. In order to realize this, one must perform the powertrain system integration and coordinate its operation through supervisory control strategies. These control strategies are developed in a simulation environment containing the plant model of the powertrain before they can be implemented in a real-time control unit. The goal of this work is to analyze the energy management strategy which minimizes the fuel consumption in a series-parallel non-plugin hybrid electric vehicle. Global optimization is used for finding the control variables that result in the minimum fuel consumption for a specific driving cycle. In a first stage, a computational model of vehicle plant and non-optimal control strategy are created. The results from the simulation are compared against experimental data from chassis dynamometer tests. Next, a global optimization strategy is applied using dynamic programming in order to minimize total fuel consumption at the end of the driving cycle. The results from the optimization show a considerable fuel consumption reduction having as control variables not only the torque-split strategy but also the engine operating points. As contribution from this work, the computational models are made available and can be used for analyzing different control strategies for hybrid vehicles.
44

The architecture of pneumatic regenerative systems for the diesel engine

Bao, Ran January 2015 (has links)
For vehicles whose duty cycle is dominated by start-stop operation, fuel consumption may be significantly improved by better management of the start-stop process. Pneumatic hybrid technology represents one technology pathway to realise this goal. Vehicle kinetic energy is converted to pneumatic energy by compressing air into air tank(s) during the braking. The recovered air is reused to supply an air starter, or supply energy to the air path in order to reduce turbo-lag. This research aims to explore the concept and control of a novel pneumatic hybrid powertrain for a city bus application to identify the potential for improvements in fuel economy and drivability. In order to support the investigation of energy management, system architecture and control methodologies, two kinds of simulation models are created. Backward-facing simulation models have been built using Simulink. Forward-facing models have been developed in the GT-POWER and Simulink co-simulation. After comparison, the fully controllable hybrid braking system is chosen to realize the regenerative braking function. A number of architectures for managing a rapid energy transfer into the powertrain to reduce turbo-lag have been investigated. A city bus energy control strategy has been proposed to realize the Stop-Start Function, Boost Function, and Regenerative Braking Function as well as the normal operations. An optimisation study is conducted to identify the relationships between operating parameters and respectively fuel consumption, performance and energy usage. In conclusion, pneumatic hybrid technology can improve the city bus fuel economy by at least 6% in a typical bus driving cycle, and reduce the engine brake torque response and vehicle acceleration. Based on the findings, it can be learned that the pneumatic hybrid technology offers a clear and low-cost alternative to the electric hybrid technology in improving fuel economy and vehicle drivability.
45

Development of a Model and Optimal Control Strategy for the Cal Poly Central Plant and Thermal Energy Storage System

Castro, Daniel Douglas 01 March 2016 (has links)
This thesis develops a calibrated model of the Cal Poly Central Chilled Water Plant with Thermal Energy Storage for use in determining an optimal operating control strategy. The model was developed using a transient systems simulation program (TRNSYS) that includes plant performance and manufacturer data for the primary system components, which are comprised of pumps, chillers, cooling towers, and a thermal energy storage tank. The model is calibrated to the actual measured performance of the plant using the current control strategy as a baseline. By observing and quantifying areas for potential improvement in plant performance under conditions of high campus cooling load demands, alternative control strategies for the plant are proposed. Operation of the plant under each of these control strategies is simulated in the model and evaluated for overall energy and demand-usage cost savings. These results are used to recommend improvements in the plant’s current control strategy, as well as to propose an optimal control strategy that may be applied to reduce plant operating costs. The results of the model identify that the plant can perform more economically by employing more chiller power to charge the Thermal Energy Storage tank to higher capacities during overnight periods when the utility rates are lower. Staging the operation of the different chillers to more precisely follow the tank charges during these off-peak periods can ensure faster tank charging when its capacity may not be sufficient to meet the peak and part-peak cooling load demands. A proposed control strategy to accomplish this breaks the overnight Off-Peak rate period into three periods with separate control setpoints, which are designed to maintain the tank charge capacity at the minimum levels to be able to accommodate the daily campus cooling demands during peak and part-peak hours.
46

Control System of Building using Modelling and Simulation / Control System of Building using Modelling and Simulation

Mohamad, Mohamad Kheir Unknown Date (has links)
Udržovaní vnitřních klimatických podmínek tak, aby byly v souladu s tepelným komfortem lidí, je klíčovou otázkou pro řízení systémů vytápění, větrání a klimatizace (HVAC systémy). Počítačové modelování nabízí virtuální prostředí pro simulaci vnitřních i vnějších podmínek a s jeho pomocí je možné navrhnout řešení pro řízení technických zařízení budov. Tento proces vyžaduje pochopení těchto prostředí z fyzikálního a matematického hlediska tak, aby bylo možné fyzikální procesy daných prostředí prezentovat pomocí vztahů a rovnic odrážejících jejích různé parametry. Simulační proces dále nabízí možnost popsat interakci mezi těmito modely a jejich chování v čase, dává výchozí reprezentace těchto prostředí, a umožňuje pochopení jejich chování před přenosem těchto modelů do reálných aplikací. Simulace umožnuje respektovat, a ovlivňovat jejích chování přes kontrolu navržených modelů. MATLAB/SIMULINK software má pokročilé schopnosti pro simulace systémů HVAC, a to vytvořením širokého pracovního prostředí pro designéry v závislosti na vývoji matematických modelů a jejích simulace pomocí SIMULINK, aby výsledky mohly být slučitelné s požadovanými výstupy. Tato dizertační práce se zaměřuje na proces modelování vnitřního prostředí v budovách, aby bylo možné pochopit chování klíčových parametrů, které mají vliv na tepelnou pohodu obyvatel či uživatelů, matematické modely vnitřního prostředí posluchárny byly navržené speciálně pro tři základní parametry: koncentrace oxidu uhličitého, teplota vzduchu a relativní vlhkost. Změny chování těchto parametrů v průběhu času jsou simulovány a poté strategie kontroly návrhu těchto parametrů může je udržet ve vhodných rozmezích komfortních pro obyvatele či uživatele, i když změny venkovního klimatu, tepelné a hmotnostní zatíží interiér. Pomocí matematických metod, některé optimalizační metody byly navrženy za účelem snížení spotřeby energie bez vlivu na mezní hodnoty těchto parametrů. Proces validace modelu se provádí porovnáním výsledků s reálnými výstupy monitoringu Honeywell Enterprise Buildings Integrator systémem (EBI) nainstalován v areálu univerzity.
47

A Lateral Positioning Strategy for Connected and Automated Vehicles in Lane-free Traffic

Faros, Ioannis, Yanumula, Venkata Karteek, Typaldos, Panagiotis, Papamichail, Ioannis, Papageorgiou, Markos 22 June 2023 (has links)
An optimal-control based path planning algorithm has been developed recently for Connected and Automated Vehicles (CAVs) driving on a lane-free highway, including vehicle nudging. That vehicle movement strategy considers, in the lateral direction, a lateral desired speed that had been set to zero in previous works; in other words, vehicles avoid lateral movement if this is not helpful in achieving some of their goals, e.g. achieving a longitudinal desired speed by overtaking slower vehicles. In this work, a lateral positioning strategy for the vehicles is proposed, aiming to improve the vehicles’ longitudinal speeds and the traffic flow, mainly at intermediate densities, by distributing laterally the vehicles based on their longitudinal desired speeds. The intention is to leverage the existing optimal control formulation to move the CAVs to appropriate lateral positions, while respecting other, higher-priority sub-objectives, such as avoiding crashes. First, the longitudinal desired speed of each vehicle is mapped to a lateral desired position under the premise “faster vehicles drive farther left”. Then, the value of the desired lateral speed is updated in real-time in dependence on the vehicle’s current versus the desired lateral position, letting the optimal control problem, with the given sub-objective priorities, decide on the actual vehicle path. The proposed strategy is demonstrated via traffic simulations, involving various traffic densities, on a ring-road. Several quantities, such as the reached average flows and statistical measures of the error in the lateral position are computed for evaluation and comparison purposes.
48

Automation and synchronizationof traction assistance devices toimprove traction and steerability ofa construction truck

Dabhi, Meet, Vaidyanathan, Karthik Ramanan January 2017 (has links)
Automotive development has always been need-based and the product of today is an evolutionover several decades and a diversied technology application to deliver better products to theend users. Steady increase in the deployment of on-board electronics and software is characterizedby the demand and stringent regulations. Today, almost every function on-board a modernvehicle is either monitored or controlled electronically.One such specic demand for AB Volvo arose out of construction trucks in the US market. Usersseldom have/had a view of the operational boundaries of the drivetrain components, resultingin inappropriate use causing damage, poor traction and steering performance. Also, AB Volvo'sstand-alone traction assistance functions were not suciently capable to handle the vehicle useconditions. Hence, the goal was set to automate and synchronize the traction assistance devicesand software functions to improve the traction and steerability under a variety of road conditions.The rst steps in this thesis involved understanding the drivetrain components from design andoperational boundary perspective. The function descriptions of the various traction softwarefunctions were reviewed and a development/integration plan drafted. A literature survey wascarried out seeking potential improvement in traction from dierential locking and also its eectson steerability. A benchmarking exercise was carried out to identify competitor and suppliertechnologies available for the traction device automation task.The focus was then shifted to developing and validating the traction controller in a simulationenvironment. Importance was given to modeling of drivetrain components and renement ofvehicle behavior to study and understand the eects of dierential locking and develop a differentiallock control strategy. The modeling also included creating dierent road segments toreplicate use environment and simulating vehicle performance in the same, to reduce test timeand costs. With well-correlated vehicle performance results, a dierential lock control strategywas developed and simulated to observe traction improvement. It was then implemented onan all-wheel drive construction truck using dSPACE Autobox to test, validate and rene thecontroller.Periodic test sessions carried out at Hallered proving ground, Sweden were important to re-ne the control strategy. Feedback from test drivers and inputs from cross-functional teamswere essential to develop a robust controller and the same was tested for vehicle suitability andrepeatability of results. When comparing with the existing traction software functions, the integrateddierential lock and transfer case lock controller showed signicantly better performanceunder most test conditions. Repeatable results proved the reliability of developed controller.The correlation between vehicle test scenarios and simulation environment results indicated theaccuracy of software models and control strategy, bi-directionally.Finally, the new traction assistance device controller function was demonstrated within ABVolvo to showcase the traction improvement and uncompromising steerability.
49

Driving Pattern Generation for Customized Energy Control Strategy in Hybrid Electric Vehicle Applications

Zhu, Qiujun 18 August 2014 (has links)
No description available.
50

Stable Control of Jumping in a Planar Biped Robot

Hester, Matthew S. 15 July 2009 (has links)
No description available.

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