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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.
1

Autonomous bucket emptying on hauler

Bergdahl, Anders January 2011 (has links)
This thesis proposes a method of loading a hauler with an autonomous wheelloader efficiently and with high productivity in the short loading cycle. The mainidea behind the method is to raise the bucket with only the lift until the centerof gravity has reached the height that it will have just as the material will startto fall out of the bucket and on to the hauler. When the center of gravity hasreached that height both lift and tilt will be used simultaneously to keep thecenter of gravity at a constant height. This method is both faster and moreenergy efficient than loading a hauler using only one function at a time. The method has been successfully implemented and validated by loading ahauler with three buckets with the autonomous wheel loader that is developed byVolvo CE in Eskilstuna. / autonomous wheel loader VolvoCE
2

Design nízkoprofilového nakladače / Design of low profile loader

Svatoš, Hynek January 2012 (has links)
Master thesis concerns with a design of a low profile loader. This work deals with concept design of a loader, while keeping with ergonomic, economical and psychological aspect dictated by modern society and technological know-how of today’s world with possible overview in to a near future. By extrapolating of a today’s technological development, this thesis is looking in to a design of a loader which is a solution for a lot of contemporary problems and improves utility value. The design improves working environment of operators as well as economical gain of the owners.
3

Sledování rozhodujících provozně ekonomických parametrů vybrané statisticky významné skupiny teleskopických nakladačů a jejich porovnání s dostupnými normativy

LUDAČKOVÁ, Jana January 2016 (has links)
The aim of this work is to search for and evaluation of critical operational and economic indicators in a statistically significant group of telescopic loaders and comparing them with available normativy.Práce focuses on finding operational and economic indicators in selected groups of lifters undertaking primary production, services or prodejců.Výsledky showed that the coefficients of repairs u tracked loaders correspond more coefficients for tractors with the same engine power and about the same cost than coefficients given for manipulators. Furthermore, it was shown that the repair costs are more dependent on the degree of use than the age of machine.
4

Návrh a pevnostní analýza hákového nosiče kontejnerových nástaveb MEGA HOOK 24 / The concept of the hook trailer for the container bodies of the HOOK MEGA 24

Maloch, Martin January 2017 (has links)
Aim of this master´s thesis is a design of tractor hook loader and stress analysis of selected parts using the fine element analysis. The theoretical part of the thesis describes general characteristics of hook loaders and summarizes critical research aimed on similar designs used by competition. Practical part deals with own design which consists of repetitive steps: design, analytical check, software simulation- if necessary, stress analysis. The last part is dedicated to drawing documentation. Assembly drawing, sub-assembly drawings and few parts drawings were composed.
5

Load Unit Geometry Optimization for Heavy Duty Machinery

Samuelsson, Ted January 2015 (has links)
The construction equipment industry is developing at a fast pace, increasing the expectation on the next-generation machines. Wheel loaders and backhoe loaders are part of this evolution and all subsystems in those machines need to be developed to meet the high demands in energy eciency and productivity. One of the most important parts of the wheel loader is the loading unit. This is traditionally designed using highly experienced engineers and CAD software. To simplify the early stages of this process was an optimization tool developed to generate a design outlay. The optimization will minimize the mass of the linkage since unnecessary weight will lower the eciency. The minimum can be found by moving the joints and adjusting the shape of the device. The optimization will also include constraints to assure the correct performance of the linkage. Since there are a high number of design variables, a gradient-based optimization method was used. A finite element solver was also implemented to calculate the forces and stresses in the linkage. The linkages studied in this report are one from a typical wheel loader and one from a backhoe loader. Since these machines are extremely versatile, and used formany diferent tasks, two sets of constraints are compiled. One of the constraint sets yields a linkage suitable for machines only equipped with bucket, while the other results in an all-round linkage suitable for most tools and applications. The optimized linkages are compared to existing devices. The results show that there are some improvements possible and that the software could be used to help designers. However, the optimization problem is hard to solve due to non-smooth constraints functions and numerical instabilities. This issue could be overcome by diferent means, like using automatic diferentiation, a non-gradient based optimization method, decreasing the number of constraints or decreasing the number of design variables. / Utvecklingen av anlaggningsmaskiner sker i snabb takt och detta ökar förväntningarna på framtidens maskiner. En stor andel av alla anläggningsmaskiner är hjullastare och traktorgrävare och alla delsystem på dessa maskiner måste följa med i utvecklingen. En av de viktigaste delarna pa en hjullastare ar lastaggregatet. Det designas traditionellt med hjälp av CAD mjukvara och mycket erfarna konstruktörer. För att underlätta denna process har en optimeringsrutin utvecklats, som generarar ett designförslag. Optimeringen minskar länkagets massa genom att fytta lagringspositioner och ändra delarnas dimensioner. Detta ökar efektiviteten hos maskinen eftersom den slipper köra runt på onödig vikt. Optimeringen innehåller även villkor för att säkerställa god prestanda hos det optimerade aggregatet. Eftersom det ingår väldigt många designvariabler i optimeringen används en gradientbaserad metod. En finita element approximation används for att beräkna krafter och spänningar i länkaget. De länkage som undersöks i detta projekt är ett typsikt hjullastaraggregat och ett typiskt traktorgrävaraggregat. Eftersom dessa maskiner ar väldigt mångsidiga sammanställdes två olika uppsättningar av villkor. Den ena uppsättningen används för att optimera ett aggregat som endast ska användas med skopa, medan den andra uppsättningen används för att ta fram ett mer mångsidigt aggregat avsätt for att kunna klara av de flesta situationer och verktyg. De optimerade lastaggregaten är jämförda med produktionsaggregat och det visar sig att vissa förbättringar är möjliga. Slutsattsen är att optimeringsrutinen kan bli ett bra hjälpmedel for konstruktörer men att den behöver lite mer veriering. Villkorsfunktionen som optimeringen måste lösa är inte helt slät vilket är ett problem för en gradientbaserade metod och dessutom finns vissa numeriska instabiliteter. Dessa svårigheter kan undkommas pa olika sätt, t.ex. genom att använda automatisk derivering,byta optimeringsalgoritm, minska antalet villkor eller minska antalet variabler.
6

Ativação de componentes de software com a utilização de uma ontologia de componentes / Component loading with utilization of a components ontology

Lorza, Augusto Carbol 16 July 2007 (has links)
Atualmente, existem muitos estudos para agregar mais valor às informações disponíveis na Web visando melhorar os resultados da interação dos usuários com a Web; uma das linhas de estudo é a Web Semântica, que propõe a adição de informação semântica à Web atual por meio de ontologias. A organização internacional que define os padrões para a Web (W3C) já propôs vários padrões para tornar a Web Semântica viável, porém, além de padrões, também é preciso criar ou adaptar ferramentas que explorem as suas potencialidades. Uma ferramenta que dá um suporte significativo para a Web atual e que pode ser adaptada para trabalhar com a Web Semântica é o Servidor de Aplicações. Com adição de informações semânticas, na forma de ontologias, tem-se um Servidor de Aplicações Baseado em Ontologias (OBAS). Neste trabalho foi desenvolvido um sistema protótipo para oferecer as características mínimas de um OBAS, e desta forma, foram investigadas as tecnologias para a Web Semântica que viabilizassem uma solução de acordo com os padrões recomendados pela W3C. Os componentes de software de um OBAS têm suas propriedades e comportamentos relacionados de forma semântica usando-se ontologias. Como uma ontologia é um modelo conceitual explícito, suas descrições dos componentes podem ser consultadas e inferidas, melhorando o desempenho do servidor através da combinação dos componentes mais apropriados a uma tarefa, da simplificação da programação, pois não é mais necessário saber todos os detalhes de um componente para ativá-lo / Many studies have been carried out to add more value to the available information in the Web with a view to improving the results of the users\' interaction with the Web. Semantic Web is one line of research with focus on this issue and proposes the insertion of semantic information to the current Web through ontologies. Several patterns have been proposed by W3C, the international organization that defines patterns to the Web as an attempt to make the Semantic Web viable. However, besides patterns, it is also necessary to create or adapt tools to explore their potentialities. Application Server is a tool which gives significant support to the current Web and could be adapted to work with the Semantic Web. By adding semantic information, in the ontology form, we have an Ontology-Based Application Server (OBAS). This study develops a protoptype system which aims to offer the minimum characteristics of an OBAS. We have therefore investigated the semantic web which could provide a solution according to the patterns recommended by W3C. Properties and behaviors of software components of OBAS are semantically related by means of ontologies. Given that ontology is an explicit conceptual model, its component descriptions can be consulted and inferred, and hence improve the performance of the server. This is done by applying the most appropriate components to a given task and simplifying programming since components can be activated with no need to know all their details
7

Automatic bucket fill

Almqvist, Håkan January 2009 (has links)
<p>This report contains the first step towards a complete, fully autonomous, robust bucket fill regulator for a wheel loader working with gravel materials.</p><p>The bucket fill procedure is the most critical part of the work cycle of a wheel loader. It is a task that has a long learning curve and also is weary, even for experienced drivers. The automation of it could therefore have a big impact on the cost effectiveness for wheel loaders and for the comfort of the drivers.</p><p>In this report, a suggestion for the complete solution of an automatic bucket fill regulator is presented. A regulator prototype is also constructed with a Volvo L120F as the base. The scope for the prototype is limited to one type of gravel material and quite optimal conditions for the wheel loader, but the complete solution is kept in mind throughout the synthesis. The constructed regulator is prepared for expansion, but the implementation and field testing is limited to the scope.</p>
8

Automatic bucket fill

Almqvist, Håkan January 2009 (has links)
This report contains the first step towards a complete, fully autonomous, robust bucket fill regulator for a wheel loader working with gravel materials. The bucket fill procedure is the most critical part of the work cycle of a wheel loader. It is a task that has a long learning curve and also is weary, even for experienced drivers. The automation of it could therefore have a big impact on the cost effectiveness for wheel loaders and for the comfort of the drivers. In this report, a suggestion for the complete solution of an automatic bucket fill regulator is presented. A regulator prototype is also constructed with a Volvo L120F as the base. The scope for the prototype is limited to one type of gravel material and quite optimal conditions for the wheel loader, but the complete solution is kept in mind throughout the synthesis. The constructed regulator is prepared for expansion, but the implementation and field testing is limited to the scope.
9

Psykosocial   arbetsmiljö   och   besvärsförekomst    bland   flygplanslastare

Lindström, Jenny January 2011 (has links)
The purpose of this study was to describe perceived psychosocial work environment and musculoskeletal complaints among baggage handlers, and to evaluate whether there is any linear relationship between them. The study is a questionnaire based cross-sectional study, and part of an ongoing larger project. Therefore, the number of forms has been limited to those that were collected in the project by 2010-11-25 (N=117). The questions analyzed in the study come from the Copenhagen Psychosocial Questionnaire and “Nordiska Ministerrådets formulär om besvär i rörelseorganen”, respectively. In addition, ratings of pain intensity according to Borg CR-scale have been used. Linear correlations were assessed by Spearman’s rank correlation. The results showed that the baggage handlers rated good sense of Community and low Emotional demands, but poor Influence and Feedback at the workplace. Their ratings of pain frequency and intensity were relatively low, but the regions where they had most complaints were shoulders and low back. The highest correlation was -0.36 between Meaning and pain frequency in the Shoulders. No particular psychosocial factor or body region appeared highly correlated with all or most of the other variables. For the psychosocial environment factors investigated in this study no extremely good or extremely bad values were discovered. Musculoskeletal complaints were low. No strong correlations between baggage handlers ratings of psychosocial work environment and musculoskeletal complaints were found in this study.
10

Dynamic Modelling Of A Backhoe-loader

Kilic, Boran 01 September 2009 (has links) (PDF)
The aim of this study is to develop a dynamic model of the loader system of a backhoe-loader. Rigid bodies and joints in the loader mechanism and loader hydraulic system components are modelled and analyzed in the same environment using the physical modelling toolboxes inside the commercially available simulation software, MATLAB/Simulink. Interaction between the bodies and response of the hydraulic system are obtained by co-operating the mechanical and hydraulic analyses. System variables such as pressure, flow and displacement are measured on a physical machine and then compared with the simulation results. Simulation results are consistent with the measurement results. The main result of this work is the ability to determine the dynamic loads on the joints and attachments of the backhoe-loader. In addition to that, prototyping time and costs can be highly reduced by implementing this model in the design process.

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