For a general J wheeled mobile platform capable of up to 3-Degrees-Of-Freedom (DOF) planar motion, there are up to 2J independent input parameters yet the output of the planar platform is specified with only three independent parameters. Currently, the motion synthesis for such platforms is done with a Jacobian based “pseudo” inverse that uses a rectangular matrix for Jacobian. However, a mobile platform is a parallel mechanism and has a more direct solution to the inverse kinematics problem. To this effect, we propose a physical methodology for kinematic modeling of multi-wheeled mobile platforms using Instant Centers (IC) to describe the kinematic state of all system points up to the kth order using a generalized algebraic formulation. This is achieved by using a series of ICs (velocity, acceleration, jerk, etc.) where each point in the system has a time state with its magnitude proportional to the radial distance of the point from the associated IC and at a constant angle relative to that radius. The use of IC’s for mobile platform kinematics is not new, however we present a completely generalized and extensive formulation that also treats the higher order kinematics. To the best of our knowledge, this is the first time the third and higher order ICs have been presented in the literature. The components of this research effort are: (i) extension of the theory of instantaneous invariants to the higher order motion by generalizing the theory to any order, (ii) studying some special case 1-DOF, 2-DOF motions to understand the physical nature of the higher order ICs, (iii) applying the results of (i) and (ii) to the motion synthesis of planar, wheeled mobile platforms by first categorizing them into four distinct categories, and (iv) studying the dynamic model of a representative mobile platform to emphasize the importance of wheel dynamics and traction parameters on the performance of the mobile platform. The IC based formulation presents a concise expression for a general order time state of a general point on the rigid body with the magnitude and direction separated and identified. We showed that the method based on instant centers provides a straightforward and yet physically intuitive way to synthesize a general kth order planar motion of mobile platforms. The study of special case 1-DOF/2-DOF motions emphasized the geometric nature of the higher order ICs and also helped understand the influence of instantaneous kinematic states (such as angular velocity _, angular acceleration, _, etc.) on the various ICs. The application of this theory to planar mobile platform allowed us to categorize the platforms based on their dexterity and to generalize the motion synthesis to some extent. The study of the dynamic model of a representative mobile platform showed us that the redundant inputs (2J inputs versus 3 outputs) in this case may be employed to sustain and manage the uncertainties and nonlinearities in the wheel ground interaction. / text

Submitted by Luciana Sebin (lusebin@ufscar.br) on 2016-10-05T18:53:36Z No. of bitstreams: 1 DissGPR.pdf: 4260232 bytes, checksum: 502932c8b3d277cbd1c02a8b1b48b913 (MD5) / Approved for entry into archive by Marina Freitas (marinapf@ufscar.br) on 2016-10-13T20:18:54Z (GMT) No. of bitstreams: 1 DissGPR.pdf: 4260232 bytes, checksum: 502932c8b3d277cbd1c02a8b1b48b913 (MD5) / Approved for entry into archive by Marina Freitas (marinapf@ufscar.br) on 2016-10-13T20:19:05Z (GMT) No. of bitstreams: 1 DissGPR.pdf: 4260232 bytes, checksum: 502932c8b3d277cbd1c02a8b1b48b913 (MD5) / Made available in DSpace on 2016-10-13T20:19:14Z (GMT). No. of bitstreams: 1 DissGPR.pdf: 4260232 bytes, checksum: 502932c8b3d277cbd1c02a8b1b48b913 (MD5) Previous issue date: 2016-03-07 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / The evolution of Computer Graphics, supported by the computational development, enables increasingly advanced visual creations and promotes benefits to various areas such as: Art, architecture, Product Design, Visual Design, Games, Movies, Engineering, GIS and Medicine. However, the processing power needed for applications that require a high degree of realism, restricts the use of these applications to a small portion of the entire range of the computing devices in use by the population. Recently, the evolution of mobile network technologies brought a possible solution to the inability of most mobile devices in dealing with interactive applications and a high degree of realism. The solution is based on the remote processing of applications on servers with high processing capacity, and delivery of the images produced for mobile devices made by its conversion into video and streaming broadcasts. This master dissertation explores a remote processing solution for interacting with architectural environments through tablets. Emphasis was placed in: keeping high degree of realism, difficult to achieve due to the processing requirements in real-time interactive applications; the adaptation and combination of tools available in the market; and in mitigating latency through different ways of user interaction. The evaluation of the results was carried out in training sessions, interaction and interviews with volunteers. / A evolução da Computação Gráfica apoiada no desenvolvimento computacional possibilita criações visuais cada vez mais avançadas promovendo benefícios a diversas áreas como: Artes, Arquitetura, Design de produto, Design visual, Jogos, Cinema, Engenharia, Geoprocessamento e Medicina. Porém, a capacidade de processamento exigida por aplicações que requerem elevado grau de realismo restringe o uso dessas aplicações a uma parcela pequena de toda a gama de dispositivos computacionais instalados e de uso da população. Recentemente, a evolução das tecnologias de rede móvel trouxe uma possível solução à incapacidade da maioria dos dispositivos móveis em lidar com aplicações interativas e de elevado grau de realismo. A solução baseia-se no processamento remoto das aplicações, em servidores com elevada capacidade de processamento, e na entrega das imagens produzidas para os dispositivos móveis feita através de sua conversão em vídeo e transmissão por streaming. Este trabalho explora uma solução de processamento remoto para interação com ambientes arquitetônicos através de tablets. Deu-se ênfase às questões de manutenção de elevado grau de realismo, dificultada pelas exigências de processamento em tempo real de aplicações interativas, à adaptação e combinação de ferramental disponível no mercado e à mitigação da latência através de recursos de interface com usuário. A avaliação dos resultados foi realizada em sessões de treinamento, interação e entrevistas com usuários voluntários.

(in English): Thesis deals with the phenomenon of m-commerce. History section briefly describes the evolution and significant moments for further development of this segment and its subsequent adaptation. It also discusses the types of transactions that are carried out through mobile devices and also about technologies that allow for a gradual transformation of these devices into multifunctional objects. The fourth chapter deals with the evaluation of practical research, which was carried out by me. The research was focused on the typology of purchases that are realized by Czech users through their mobile devices (smartphones and tablets) in relation to mobile smartphone platform, which they own.

Made available in DSpace on 2016-06-02T19:06:14Z (GMT). No. of bitstreams: 1 6118.pdf: 3001954 bytes, checksum: 5643531722be67da01c9dfa9c79f4ecb (MD5) Previous issue date: 2014-05-22 / Financiadora de Estudos e Projetos / Computer graphics and virtual reality technologies allow audiovisual experiences with high level of realism, as the ones achieved in video games and movies. The synthetization of media with high degree of audiovisual realism demands specialized systems with high performance computing capacity. The profusion in the last decade of personal computing consumer electronics such as mobile and portable devices, encourages the interest in making possible, also in these devices, applications with high level of visual realism. However, due to the intrinsic limitations of the computing capability of mobile and portable devices, regarding to the physical characteristics of these devices, such as dimensions, electrical consume and heat dissipation, it s not possible directly process media with the same level of visual realism that is found in specialized systems. This research suggests the exploration of a traditional solution: the remote interaction with these applications. Challenges resulting from this approach are identified and studied. Solutions are proposed, analyzed and formalized in a architecture for reference. As a proof of concept the architecture is used in the development of applications on two scenarios: one in a local network with a media characterized by its low tolerance in delay of interaction response and another with a high tolerance media through the Internet. Also is showed the flexibility of the proposed architecture by integrating one of the applications developed with a multimedia context. / As tecnologias de computação gráfica e realidade virtual permitem experiências visuais e auditivas com alto nível de realismo sensorial, como alcançado em jogos eletrônicos e no cinema. A sintetização de mídia com alto grau de realismo visual e auditivo demanda sistemas especializados com capacidade computacional de alto desempenho. A profusão na última década de eletrônicos de consumo computacionais pessoais, como dispositivos móveis e portáteis, desperta o interesse em tornar possível, também nesses dispositivos, aplicações visuais com alto nível de realismo. Devido às limitações da capacidade computacional intrínsecas dos dispositivos móveis, decorrentes de suas características físicas, como dimensões, restrições de consumo e dissipação térmica, não é possível a execução direta de mídia interativa com o mesmo grau de realismo encontrado em sistemas especializados. Este trabalho sugere a exploração de uma solução tradicional: o processamento e a interação remota com esse tipo de mídia. Desafios decorrentes dessa solução são identificados e estudados. Soluções são propostas, analisadas e formalizadas em uma arquitetura de referência. Como prova de conceito da arquitetura explorou-se o desenvolvimento de aplicações em dois cenários: um em rede local com mídia de baixa tolerância a atrasos no tempo de resposta às interações e outra através da Internet com mídia de maior tolerância a atrasos. Mostrouse também a flexibilidade da arquitetura desenvolvida com a integração do componente cliente a um sistema com múltiplas mídias, em que a mídia remota relaciona-se integralmente com o contexto multimídia.

The aim of this work was to design a control system based on the XMega microcontroller, for a small mobile robot with an tracked undercarriage. At first, my work was to develop an electrical scheme and circuit boards for the control system. The next step was to connect sensors for non electric quantity and modify the control algorithms for a simple navigation. In the last phase I tuned the user interface and the whole control system for minimal data flow between the mobile platform and the user interface.

This thesis investigates the strengths and weaknesses of omnidirectional drive and differential drive systems on mobile manipulator robots. Based on a literature study, a hypothetical use case, and identified Key Performace Indicators the drive system’s effects on the performance of the mobile manipulator are evaluated. A qualitative approach was used for evaluation. The research methodology involved analyzing the wheel characteristics of each drive system, identifying parameters affecting the performance, and assessing the two drive system characteristics within the context of the hypothetical use case. Six Key Performance Indicators such as pose accuracy, space utilization, and manipulability were formulated and examined to determine the comparative strengths and weaknesses of the drive systems. The results confirmed that omnidirectional drive systems exhibit greater maneuverability and agility while differential drive systems are less complex and often more durable in rough conditions. However, the results also show that in many cases the answer on what drive system to use will depend on many factors and that these factors can affect the overall performance of the mobile manipulator. This study provides insights into performance-affecting parameters and relevant performance aspects by examining the strengths and weaknesses of omnidirectional and differential drive systems. While acknowledging the need for caution in generalizing the findings and assuming validity in real-world applications, the results obtained serve as a starting point for further investigations. / Detta examensarbete undersöker styrkor och svagheter hos omnidirektionella drivsystem och differentialdrivsystem på mobila manipulatorer. En kvalitativ metod, baserat på en litteraturstudie, ett hypotetiskt användningsscenario och identifierade prestationsindikatorer, användes för att utvärdera drivsystemets effekter på den mobila manipulatorns prestanda. Forskningsmetodiken innebar att analysera hjulegenskaperna för varje drivsystem, identifiera parametrar som påverkar prestandan och bedöma de två drivsystemens egenskaper inom ramen för det hypotetiska användningsfallet. Viktiga prestationsindikatorer som poserings noggrannhet, utrymmesutnyttjande och manipulerbarhet undersöktes för att fastställa och jämförande styrkorna och svagheterna hos drivsystemen. Resultaten bekräftade att omnidirektionella drivsystem uppvisar större manövrerbarhet och smidighet medan differentialdrivsystem ofta är mindre komplexa och mer hållbara under tuffa förhållanden. Dock visar resultaten även att svaret på vilket drivsystem som ska användas i många fall beror på flertalet faktorer och att dessa faktorer kan påverka den mobila manipulatorns totala prestanda. Denna studie ger insikter i prestandapåverkande parametrar och relevanta prestandaaspekter genom att undersöka styrkorna och svagheterna hos omnidirektionella och differentiella drivsystem. Samtidigt som man erkänner behovet av försiktighet med att generalisera resultaten och anta giltighet i verkliga tillämpningar, tjänar de erhållna resultaten som en utgångspunkt för ytterligare undersökningar.