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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

Návrh automatického vozíku AGV / The design of the automated truck AGV

Köhler, Tomáš January 2017 (has links)
This master thesis deals with design of the automated guided vehicle (AGV) for securing of material flow in industry. Emphasis is placed especially on the locomotion system, which includes steering mechanism, traction propulsion with gearbox and traction batteries. This thesis also includes design of the vehicle’s frame and its strength check using finite element method. Part of this thesis is also production drawings of the selected parts and total drawing set of the AGV.
42

Návrh mobilního robotu / Mobile Robot Design

Valík, Michal January 2017 (has links)
This diploma thesis deals with design of machinware of mobile robot. The purpose of this work is to design complete technical product documentation for manufacturing of a prototype. In first theoretical part of this thesis there is an analysis of contemporary situation of mobile robots. In second practical section, there is a design of all needed mechanical parts for tracked vehicle, all needed calculations are included. Diploma thesis contains hazard analysis, complete technical product documentation with 3D model included and final price statement.
43

Assessing design strategies for improved life cycle environmental performance of vehicles

Poulikidou, Sofia January 2016 (has links)
Vehicle manufactures have adopted different strategies for improving the environmental performance of their fleet including lightweight design and alternative drivetrains such as EVs. Both strategies reduce energy during use but may result in a relative increase of the impact during other stages. To address this, a lifecycle approach is needed when vehicle design strategies are developed. The thesis explores the extent that such a lifecycle approach is adopted today and assesses the potential of these strategies to reduce the lifecycle impact of vehicles. Moreover it aims to contribute to method development for lifecycle considerations during product development and material selection. Current practices were explored in an empirical study with four vehicle manufacturers. The availability of tools for identifying, monitoring and assessing design strategies was explored in a literature review. The results of the empirical study showed that environmental considerations during product development often lack a lifecycle perspective. Regarding the use of tools a limited number of such tools were utilized systematically by the studied companies despite the numerous tools available in literature. The influence of new design strategies on the lifecycle environmental performance of vehicles was assessed in three case studies; two looking into lightweight design and one at EVs. Both strategies resulted in energy and GHG emissions savings though the impact during manufacturing increases due to the advanced materials used. Assumptions relating to the operating conditions of the vehicle e.g. lifetime distance or for EVs the carbon intensity of the energy mix, influence the level of this tradeoff. Despite its low share in terms of environmental impact EOL is important in the overall performance of vehicles. The thesis contributed to method development by suggesting a systematic approach for material selection. The approach combines material and environmental analysis tools thus increases the possibilities for lifecycle improvements while minimizing risk for sub-optimizations. / <p>QC 20160920</p>
44

An integrated approach to the design of supercavitating underwater vehicles

Ahn, Seong Sik 09 May 2007 (has links)
A supercavitating vehicle, a next-generation underwater vehicle capable of changing the paradigm of modern marine warfare, exploits supercavitation as a means to reduce drag and achieve extremely high submerged speeds. In supercavitating flows, a low-density gaseous cavity entirely envelops the vehicle and as a result the vehicle is in contact with liquid water only at its nose and partially over the afterbody. Hence, the vehicle experiences a substantially reduced skin drag and can achieve much higher speed than conventional vehicles. The development of a controllable and maneuvering supercavitating vehicle has been confronted with various challenging problems such as the potential instability of the vehicle, the unsteady nature of cavity dynamics, the complex and non-linear nature of the interaction between vehicle and cavity. Furthermore, major questions still need to be resolved regarding the basic configuration of the vehicle itself, including its control surfaces, the control system, and the cavity dynamics. In order to answer these fundamental questions, together with many similar ones, this dissertation develops an integrated simulation-based design tool to optimize the vehicle configuration subjected to operational design requirements, while predicting the complex coupled behavior of the vehicle for each design configuration. Particularly, this research attempts to include maneuvering flight as well as various operating trim conditions directly in the vehicle configurational optimization. This integrated approach provides significant improvement in performance in the preliminary design phase and indicates that trade-offs between various performance indexes are required due to their conflicting requirements. This dissertation also investigates trim conditions and dynamic characteristics of supercavitating vehicles through a full 6 DOF model. The influence of operating conditions, and cavity models and their memory effects on trim is analyzed and discussed. Unique characteristics are identified, e.g. the cavity memory effects introduce a favorable stabilizing effect by providing restoring fins and planing forces. Furthermore, this research investigates the flight envelope of a supercavitating vehicle, which is significantly different from that of a conventional vehicle due to different hydrodynamic coefficients as well as unique operational conditions.
45

A hybrid probabilistic method to estimate design margin

Robertson, Bradford E. 13 January 2014 (has links)
Weight growth has been a significant factor in nearly every space and launch vehicle development program. In order to account for weight growth, program managers allocate a design margin. However, methods of estimating design margin are not well suited for the task of assigning a design margin for a novel concept. In order to address this problem, a hybrid method of estimating margin is developed. This hybrid method utilizes range estimating, a well-developed method for conducting a bottom-up weight analysis, and a new forecasting technique known as executable morphological analysis. Executable morphological analysis extends morphological analysis in order to extract quantitative information from the morphological field. Specifically, the morphological field is extended by adding attributes (probability and mass impact) to each condition. This extended morphological field is populated with alternate baseline options with corresponding probabilities of occurrence and impact. The overall impact of alternate baseline options can then be estimated by running a Monte Carlo analysis over the extended morphological field. This methodology was applied to two sample problems. First, the historical design changes of the Space Shuttle Orbiter were evaluated utilizing original mass estimates. Additionally, the FAST reference flight system F served as the basis for a complete sample problem; both range estimating and executable morphological analysis were performed utilizing the work breakdown structure created during the conceptual design of this vehicle.
46

Design and Development of 75 mm Fixed-Wing Nano Air Vehicle

Pushpangathan, Jinraj V January 2017 (has links) (PDF)
This thesis deals with the design and development of a 75 mm fixed-wing nano-air vehicle (NAV). The NAV is designed to fit inside a cube with each side measuring 75 mm. The range and endurance of the NAV are 300 m and 2-3 minutes, respectively. The high-wing horizontal tailless NAV has a take-off weight of 19.5 g. The battery-powered single propeller NAV has two control surfaces in the form of elevator and rudder. This thesis contains a detailed account of the airfoil selection, selection of the configuration of NAV and the longitudinal, lateral and directional aerodynamic characterization of the NAV. The development of one of the lightweight autopilot hardware which weighs 1.8 g is also given in detail. The development of non-linear equations of motion of NAV including thrust and coupling effects is also discussed. The effects of the gyroscopic coupling and counter torque on the linear dynamics of the NAV are analyzed by conducting a parametric study about the variation of the eigenstructure attributable to the varying degree of coupling in the system matrix of the linear coupled model. A robust simultaneously stabilizing output feedback controller is synthesized for stabilizing the plants of the NAV. The synthesizing of the robust simultaneously stabilizing output feedback controller is based on a frequency-shaped central plant. A new procedure is developed to determine the frequency-shaped central plant utilizing the v-gap metric between the plants, the frequency-shaping of the plants with the pre and post compensators and the robust stabilization theory. An optimization problem is formulated to obtain these compensators. A novel iterative algorithm is developed to acquire the compensators by solving the optimization problem. Thereafter, an iterative algorithm is developed to find an output feedback controller for robust simultaneous stabilization by blending the existing features of robust stability condition of right co-prime uncertainty model of the frequency-shaped central plant, the maximum v-gap metric of the frequency-shaped central plant, H∞ loop-shaping and eigenstructure assignment algorithm for output feedback using the genetic algorithm. The six-degree-of-freedom numerical and hardware-in-loop simulations (HILS) of closed-loop non-linear and linear plants of NAV are performed to assess the performance of the controller and to validate the control algorithm implemented in the autopilot. The airworthiness of the aircraft is tested by conducting flight trials in radio-controlled (RC) mode without including the autopilot. The successful RC flight trial of the NAV indicates airworthiness of the aircraft which aided in freezing the configuration. This is one of the smallest fixed wing aerial vehicle that was successfully flown till date.
47

Graphical visualization and analysis tool of data entities in embedded systems engineering

Supiratana, Panon January 2010 (has links)
Several decades ago, computer control systems known as Electric Control Units (ECUs) were introduced to the automotive industry. Mechanical hardware units have since then increasingly been replaced by computer controlled systems to manage complex tasks such as airbag, ABS, cruise control and so forth. This has lead to a massive increase of software functions and data which all needs to be managed. There are several tools and techniques for this, however, current tools and techniques for developing real-time embedded system are mostly focusing on software functions, not data. Those tools do not fully support developers to manage run-time data at design time. Furthermore, current tools do not focus on visualization of relationship among data items in the system. This thesis is a part of previous work named the Data Entity approach which prioritizes data management at the top level of development life cycle. Our main contribution is a tool that introduces a new way to intuitively explore run-time data items, which are produced and consumed by software components, utilized in the entire system. As a consequence, developers will achieve a better understanding of utilization of data items in the software system. This approach enables developers and system architects to avoid redundant data as well as finding and removing stale data from the system. The tool also allows us to analyze conflicts regarding run-time data items that might occur between software components at design time. / A Data-Entity Approach for Component-Based Real-Time Embedded Systems Development
48

Contributions à l'optimisation multidisciplinaire sous incertitude, application à la conception de lanceurs / Contributions to Multidisciplinary Design Optimization under uncertainty, application to launch vehicle design

Brevault, Loïc 06 October 2015 (has links)
La conception de lanceurs est un problème d’optimisation multidisciplinaire dont l’objectif est de trouverl’architecture du lanceur qui garantit une performance optimale tout en assurant un niveau de fiabilité requis.En vue de l’obtention de la solution optimale, les phases d’avant-projet sont cruciales pour le processus deconception et se caractérisent par la présence d’incertitudes dues aux phénomènes physiques impliqués etaux méconnaissances existantes sur les modèles employés. Cette thèse s’intéresse aux méthodes d’analyse et d’optimisation multidisciplinaire en présence d’incertitudes afin d’améliorer le processus de conception de lanceurs. Trois sujets complémentaires sont abordés. Tout d’abord, deux nouvelles formulations du problème de conception ont été proposées afin d’améliorer la prise en compte des interactions disciplinaires. Ensuite, deux nouvelles méthodes d’analyse de fiabilité, permettant de tenir compte d’incertitudes de natures variées, ont été proposées, impliquant des techniques d’échantillonnage préférentiel et des modèles de substitution. Enfin, une nouvelle technique de gestion des contraintes pour l’algorithme d’optimisation ”Covariance Matrix Adaptation - Evolutionary Strategy” a été développée, visant à assurer la faisabilité de la solution optimale. Les approches développées ont été comparées aux techniques proposées dans la littérature sur des cas tests d’analyse et de conception de lanceurs. Les résultats montrent que les approches proposées permettent d’améliorer l’efficacité du processus d’optimisation et la fiabilité de la solution obtenue. / Launch vehicle design is a Multidisciplinary Design Optimization problem whose objective is to find the launch vehicle architecture providing the optimal performance while ensuring the required reliability. In order to obtain an optimal solution, the early design phases are essential for the design process and are characterized by the presence of uncertainty due to the involved physical phenomena and the lack of knowledge on the used models. This thesis is focused on methodologies for multidisciplinary analysis and optimization under uncertainty for launch vehicle design. Three complementary topics are tackled. First, two new formulations have been developed in order to ensure adequate interdisciplinary coupling handling. Then, two new reliability techniques have been proposed in order to take into account the various natures of uncertainty, involving surrogate models and efficient sampling methods. Eventually, a new approach of constraint handling for optimization algorithm ”Covariance Matrix Adaptation - Evolutionary Strategy” has been developed to ensure the feasibility of the optimal solution. All the proposed methods have been compared to existing techniques in literature on analysis and design test cases of launch vehicles. The results illustrate that the proposed approaches allow the improvement of the efficiency of the design process and of the reliability of the found solution.
49

Integration of Design for Environment in the vehicle manufacturing industry in Sweden : Focus on practices and tools

Poulikidou, Sofia January 2013 (has links)
Design for Environment (DfE) promotes the systematic consideration of environmental aspects during product design and development. Despite the maturity of concepts and tools in literature, efficient implementation in industries is reported to be low. A need to bridge this gap is identified with studies that look on DfE practices as well as the use and potential of DfE tools. This thesis is part of a research project that investigates DfE practices and the use of tools during vehicle design and development. The aim is to investigate the ways that environmental constraints can be efficiently integrated into product development processes thus assist in improving the environmental performance of products from a life cycle perspective. The scope of the study includes four vehicle manufacturing companies in Sweden. The development and utilization of tools has been also investigated aiming to increase the opportunities for effective use within this product category. Case study methodology, research interviews and literature reviews constitute the research strategy followed in this work. The empirical results presented in this thesis indicated that vehicle manufacturing companies in Sweden are continually working to improve the environmental performance of their products and meet legal and costumer demands. Despite similarities regarding the type of environmental requirements considered, the companies studied have adopted different ways to identify and integrate environmental requirements into their product development process and use DfE tools to different extents. Such variations reflect differences in the success and maturity levels of the DfE practices adopted. A need for increased and more systematic use of tools is identified for all studied companies and especially for analytical tools. Results from the literature review showed that a variety of tools are available that have the potential to support vehicle design processes. However, only a few cover a broad set of aspects identified to be relevant from a vehicle design perspective. For DfE tools to become effective and be used during product development, they need to cover aspects that are relevant for the company and product designers. A need towards the development of tools that assist vehicle or product designers in general, to make informed and comprehensive choices based on a variety of requirements associated to the product, is identified. / Coupling Materials Environmental Analysis - Environmental Effects
50

Agile Project Management/Systems Engineering of an AV Interior Prototype

Clepper, Erin Grace January 2018 (has links)
No description available.

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