Simulation of a diffusion driven mobile robot

In this paper, we investigate the possibility to control a mobile robot via a sensory-motory coupling utilizing diffusion system. For this purpose, we implemented a simulation of the diffusion process of chemicals and the kinematics of the mobile robot. In comparison to the original Braitenberg vehicle in which sensorymotor coupling is tightly realised by hardwiring, our system employs the soft coupling. The mobile robot has two sets of independent sensory-motor unit, two sensors are implemented in front and two motors on each side of the robot. The framework used for the sensory-motor coupling was such that 1) Place two electrodes in the medium 2) Drop a certain amount of Chemical U and V related to the distance to the walls and the intensity of the light 3) Place other two electrodes in the medium 4) Measure the concentration of Chemical U and V to actuate the motors on both sides of the robot. The environment was constructed with four surrounding walls and a light source located at the center. Depending on the design parameters and initial conditions, the robot was able to successfully avoid the wall and light. More interestingly, the diffusion process in the sensory-motor coupling provided the robot with a simple form of memory which would not have been possible with a control framework based on a hard-wired electric circuit.

Cluster's last stand?

On 4 June last year the first attempt to make three-dimensional measurements in space was lost when the Ariane 5 rocket veered off course and self-destructed, 39 s into its maiden flight. On board were four identical spacecraft which made up Cluster,a mission that the European Space Agency called a “cornerstone” of its Horizon 2000 scientific programme. A full description of the Cluster satellites is given in a special issue of Space Science Reviews (Escoubet et al. 1997). Their loss dealt a devastating blow to the Cluster scientists and to those working on other missions and projects planned to interact with Cluster. Many discoveries have been made during the 15 years in which Cluster progressed from an idea to the state-of-the-art satellites that were on top of Ariane 501 on 4 June. However, these discoveries invariably underline rather than undermine the importance of Cluster. Now plans to recover the unique and exciting research that was to be done using Cluster are well advanced.

Dual drive series actuator

Industrial robotic manipulators can be found in most factories today. Their tasks are accomplished through actively moving, placing and assembling parts. This movement is facilitated by actuators that apply a torque in response to a command signal. The presence of friction and possibly backlash have instigated the development of sophisticated compensation and control methods in order to achieve the desired performance may that be accurate motion tracking, fast movement or in fact contact with the environment. This thesis presents a dual drive actuator design that is capable of physically linearising friction and hence eliminating the need for complex compensation algorithms. A number of mathematical models are derived that allow for the simulation of the actuator dynamics. The actuator may be constructed using geared dc motors, in which case the benefits of torque magnification is retained whilst the increased non-linear friction effects are also linearised. An additional benefit of the actuator is the high quality, low latency output position signal provided by the differencing of the two drive positions. Due to this and the linearised nature of friction, the actuator is well suited for low velocity, stop-start applications, micro-manipulation and even in hard-contact tasks. There are, however, disadvantages to its design. When idle, the device uses power whilst many other, single drive actuators do not. Also the complexity of the models mean that parameterisation is difficult. Management of start-up conditions still pose a challenge.

Cellular automaton model for molecular traffic jams

We consider the time evolution of an exactly solvable cellular automaton with random initial conditions both in the large-scale hydrodynamic limit and on the microscopic level. This model is a version of the totally asymmetric simple exclusion process with sublattice parallel update and thus may serve as a model for studying traffic jams in systems of self-driven particles. We study the emergence of shocks from the microscopic dynamics of the model. In particular, we introduce shock measures whose time evolution we can compute explicitly, both in the thermodynamic limit and for open boundaries where a boundary-induced phase transition driven by the motion of a shock occurs. The motion of the shock, which results from the collective dynamics of the exclusion particles, is a random walk with an internal degree of freedom that determines the jump direction. This type of hopping dynamics is reminiscent of some transport phenomena in biological systems.

Motor Winding Students at Work

This photo shows a classroom of students working on motors. Photograph is black and white.

Jämförande analys mellan svenska och portugisiska reklambyråer. : Saker som är bra att veta om man ska arbeta som grafisk formgivare i Sverige eller i Portugal

If you move from Sweden to Portugal to work as an Art Director at an Ad agency, there are certain things you ought to know. Perhaps even before you decide to move. There are a lot of things that are quite different if you compare Portugal to Sweden, not only the language, but also the design, software, working hours and much more. You have for example two month with double salary, you work till six p.m. and when it comes to maternity leave, you have 100% compensation with no taxes the first four months of every pregnancy. The tasks you have to handle as an Art Director in Portugal may, as in Sweden, be various. The difference is more how you solve your task and what the design looks like. As a Swede in Portugal the solution will probably look like a mixture between the Portuguese “expressive” and the Swedish “clean” design. This degree project discusses questions that might turn up when a Swede gets employed as an Art Director in Portugal. What will the salary be? When, in the morning, is it time to show up at the office? How many weeks of vacations are entitled? There are a lot of distinctions, but also a lot of similarities. The report is mainly based upon the author’s own experiences of the Ad agency McCann-Erickson in Lisbon. The history of McCann-Erickson starts in New York, 1930 and grew rapidly into one of the leading corporation with agencies all over the world. It is still today one of the world’s largest Ad company with clients like Coca-Cola and General Motors, and the slogan “truth well told” still lights up all their agencies after almost a century, just like a leading star.

Energy Analysis within Industrial Hydraulics and Correspondent Solar PV System Design

Energy efficiency and renewable energy use are two main priorities leading to industrial sustainability nowadays according to European Steel Technology Platform (ESTP). Modernization efforts can be done by industries to improve energy consumptions of the production lines. These days, steel making industrial applications are energy and emission intensive. It was estimated that over the past years, energy consumption and corresponding CO2 generation has increased steadily reaching approximately 338.15 parts per million in august 2010 [1]. These kinds of facts and statistics have introduced a lot of room for improvement in energy efficiency for industrial applications through modernization and use of renewable energy sources such as solar Photovoltaic Systems (PV).The purpose of this thesis work is to make a preliminary design and simulation of the solar photovoltaic system which would attempt to cover the energy demand of the initial part of the pickling line hydraulic system at the SSAB steel plant. For this purpose, the energy consumptions of this hydraulic system would be studied and evaluated and a general analysis of the hydraulic and control components performance would be done which would yield a proper set of guidelines contributing towards future energy savings. The results of the energy efficiency analysis showed that the initial part of the pickling line hydraulic system worked with a low efficiency of 3.3%. Results of general analysis showed that hydraulic accumulators of 650 liter size should be used by the initial part pickling line system in combination with a one pump delivery of 100 l/min. Based on this, one PV system can deliver energy to an AC motor-pump set covering 17.6% of total energy and another PV system can supply a DC hydraulic pump substituting 26.7% of the demand. The first system used 290 m2 area of the roof and was sized as 40 kWp, the second used 109 m2 and was sized as 15.2 kWp. It was concluded that the reason for the low efficiency was the oversized design of the system. Incremental modernization efforts could help to improve the hydraulic system energy efficiency and make the design of the solar photovoltaic system realistically possible. Two types of PV systems where analyzed in the thesis work. A method was found calculating the load simulation sequence based on the energy efficiency studies to help in the PV system simulations. Hydraulic accumulators integrated into the pickling line worked as energy storage when being charged by the PV system as well.

Brytmånens utformning vid trädfällning - Jämförande studier av böjmotstånd och gångjärnseffekt : Designing felling hinge in tree felling - Comparative studies of bending resistance and hinge effect

Vid trädfällning med motorsåg sparar man en så kallad brytmån som skall fungera som ett gång¬järn när trädet fälls. Om brytmånen går av tidigt finns en risk att trädet faller okontrolle¬rat. De rekommendationer som finns säger att brytmånens bredd skall göras proportionell mot trädets diameter. Genom att teoretiskt och praktiskt undersöka vilka krafter brytmånen utsätts för och vad den håller för har det varit möjligt att dra vissa slutsatser om hur en bra brytmån skall se ut. Ett viktigt resultat är att en bred brytmån (över 30-40 mm) är mycket trög att böja och inte fungerar i det avseendet att den går av redan vid små böjningar. Teoretiska be¬räkningar och praktiska försök visar att en relativt smal brytmån håller för belastningen vid rakt motlut även på stora träd. Som ny rekommendationen föreslås att brytmånens bredd inte bör vara mer än 30 mm. Av försöken kan man också dra slutsatsen att frusen ved är stel och brister tidigt, varför svår¬fällda träd inte bör fällas när veden är fryst.A felling hinge is used when felling trees by help of chain saw. If the hinge breaks early in the fall of the tree there is a great risk that the tree will fall without control. Present recommenda¬tions in Sweden say that the thickness of the felling hinge shall be made in proportion to the stem diameter. By use of theoretical and practical examinations of the forces stressing the felling hinge, and the strength of the wood itself, it has been possible to draw conclusions regarding the correct design of a felling hinge. One important result is that a thick felling hinge (over 30-40 mm) is very hard to bend and does not work well as it looses most of its strength already at a small forward bending angel. Theoretical calculations and practical tests show that a relatively narrow felling hinge will manage very well the forces when felling trees with lean opposite to the felling direction even for large trees. Our new recommendation is that the thickness of the felling hinge in normal Swedish conditions should not exceed 30 mm. Through the studies it can also be seen that frozen, brittle wood breaks at small bending angels. For that reason particularly difficult trees not should be felled when the wood is frozen.

Use of Photovoltaic on an E-bike? : A Feasibility Study

In recent years the number of bicycles with e-motors has been increased steadily. Within the pedelec – bikes where an e-motor supports the pedaling – a special group of transportation bikes has developed. These bikes have storage boxes in addition to the basic parts of a bike. Due to the space available on top of those boxes it is possible to install a PV system to generate electricity which could be used to recharge the battery of the pedelec. Such a system would lead to grid independent charging of the battery and to the possibility of an increased range of motor support. The feasibility of such a PV system is investigated for a three wheeled pedelec delivered by the company BABBOE NORDIC.The measured data of the electricity generation of this mobile system is compared to the possible electricity generation of a stationary system.To measure the consumption of the pedelec different tracks are covered, and the energy which is necessary to recharge the bike battery is measured using an energy logger. This recharge energy is used as an indirect measure of the electricity consumption. A PV prototype system is installed on the bike. It is a simple PV stand alone system consisting of PV panel, charge controller with MPP tracker and a solar battery. This system has the task to generate as much electricity as possible. The produced PV current and voltage aremeasured and documented using a data logger. Afterwards the average PV power is calculated. To compare the produced electricity of the on-bike system to that of a stationary system, the irradiance on the latter is measured simultaneously. Due to partial shadings on the on-bike PV panel, which are caused by the driver and some other bike parts, the average power output during riding the bike is very low. It is too low to support the motor directly. In case of a similar installation as the PV prototype system and the intention always to park the bike on a sunny spot an on-bike system could generate electricity to at least partly recharge a bike battery during one day. The stationary PV system using the same PV panel could have produced between 1.25 and 8.1 times as much as the on-bike PV system. Even though the investigation is done for a very specific case it can be concluded that anon-bike PV system, using similar components as in the investigation, is not feasible to recharge the battery of a pedelec in an appropriate manner. The biggest barrier is that partial shadings on the PV panel, which can be hardly avoided during operation and parking, result in a significant reduction of generated electricity. Also the installation of the on-bike PV system would lead to increased weight of the whole bike and the need for space which is reducing the storage capacity. To use solar energy for recharging a bike battery an indirect way is giving better results. In this case a stationary PV stand alone system is used which is located in a sunny spot without shadings and adjusted to use the maximum available solar energy. The battery of the bike is charged using the corresponding charger and an inverter which provides AC power using the captured solar energy.

Jornalismo e interesses econômico-políticos : o caso das montadoras e o governo do PT em Zero Hora : 1999, o ano em que o jornal abandona o neoliberalismo e se torna "Keynesiano"

Este trabalho analisa a cobertura do jornal Zero Hora sobre o impasse entre o governo do Rio Grande do Sul e as montadoras de automóveis Ford e General Motors, no período de 16/03/1999 a 03/05/1999. É um estudo que procura, através do referencial da hermenêutica de profundidade, demonstrar como é construída a ideologia no jornalismo do grupo RBS – maior conglomerado de mídia da região Sul do Brasil –, com base no conceito proposto por Thompson de “sentido a serviço do poder”. A minuciosa pesquisa possibilitou perceber não só o agendamento de Zero Hora no caso envolvendo o governo do Partido dos Trabalhadores (PT) e as montadoras, mas a construção ideológica empreendida pelo jornal, legitimando o discurso das montadoras e da oposição, e desqualificando os argumentos do governo. O discurso neoliberal de redução das atribuições do Estado, hegemônico nas páginas de Zero Hora durante a década de 90, é trocado – nos primeiros meses do governo petista – por um discurso fragmentado, oportunista e descontextualizado do pensamento keynesiano, defendendo o papel importante do Estado na geração de emprego e renda, como propulsor do desenvolvimento através de investimentos e outras políticas de incentivos capazes de gerar um círculo virtuoso na economia. A cobertura tendenciosa de Zero Hora se tornaria um dos elementos constitutivos de um Cenário de Representação da Política (CR-P) desfavorável à candidatura petista na eleição para o governo do Rio Grande do Sul em 2002.

Estratégias locais e globais na indústria automobilística brasileira

Este estudo caracteriza as estratégias de internacionalização das grandes fabricantes mundiais de veículos, caracteriza as estratégias adotadas por suas filiais no Brasil e faz um confronto entre estratégias locais e internacionais. Através do estudo de caso de cinco grandes montadoras (General Motors, Volkswagen, Toyota, DaimlerChrysler e Renault-Nissan), mostra-se que as estratégias de internacionalização das matrizes dessas empresas são muito semelhantes entre si e que as estratégias seguidas por suas filiais, que parecem buscar alinhá-las com as estratégias das respectivas matrizes, também se parecem muito. São discutidas as implicações desses achados para o futuro do ramo no Brasil e as oportunidades que esta situação apresenta para o país.

O impacto da orientação para o mercado sobre o desempenho financeiro: as concessionárias de veículos da Fiat no Brasil

Este relatório trata de uma pesquisa sobre o Impacto da Orientação para o Mercado sobre o Desempenho Financeiro. Foi realizada uma revisão teórica e seguiu-se o delineamento de um modelo conceitual. Tal modelo foi testado empiricamente com os dados de uma amostra de 122 executivos principais de concessionárias de veículos da Fiat operando no Brasil, utilizando-se do método de modelagem de equações estruturais. Numa etapa anterior, a mesma análise foi aplicada a uma amostra de dirigentes de concessionárias da General Motors no país. Nesta etapa, apesar das limitações incidentes, o ajustamento global do Modelo revelou-se pequeno. Em especial, apenas o vínculo causal entre o componente Orientação para a Concorrência da Orientação para o Mercado mostrou como causa significantes do Desempenho Financeiro. Os resultados são discutidos à luz da literatura e suas implicações avaliadas. Mais pesquisas são necessárias para compreender esses complexos fenômenos.

O impacto da orientação para o mercado sobre o desempenho financeiro: as concessionárias de veículos da Ford e Volkswagen

Este relatório trata de uma pesquisa sobre o Impacto da Orientação para o Mercado sobre o Desempenho Financeiro. Foi realizada uma revisão teórica e seguiu-se o delineamento de um modelo conceitual. Tal modelo foi testado empiricamente com os dados de uma amostra de 294 executivos de concessionárias de veículos da Ford e Volkswagen operando no Brasil, utilizando-se do método de modelagem de equações estruturais. Em duas etapas anteriores, a mesma análise foi aplicada a amostras ligadas à Fiat e General Motors. Desta feita, o ajustamento global do Modelo revelou-se pequeno. Apenas o vínculo causal entre o componente Orientação para a Concorrência da Orientação para o Mercado mostrou-se como causa significante do Desempenho Financeiro. Os resultados são discutidos à luz da literatura, sendo suas implicações avaliadas. Mais pesquisas são necessárias para compreender tais complexos fenômenos.

A influência da conectividade no desempenho de uma cadeia de suprimentos característica do setor automobilístico brasileiro utilizando a dinâmica de sistemas

A centenária indústria automobilística, um dos elementos responsáveis pela condução da economia mundial ao longo do século XX, tem liderado e ao mesmo tem sido alvo de intensas mudanças provocadas pelo fortalecimento dos processos de globalização, onde se instala um ambiente de competição extrema, e cujo cenário se estende a todos os níveis de sua cadeia produtiva. Hoje testemunhamos a liderança construída ao longo do século XX, pela gigante americana General Motors, ser ultrapassada pela montadora japonesa Toyota. A competição global não se processa mais entre empresas de forma isolada, e sim entre cadeias de suprimentos, cuja gestão transcende as relações formais entre as empresas, tornando-se cada vez mais complexa e de difícil previsibilidade e estabilidade. Por outro lado, persiste, tanto nos meios acadêmicos como no empresarial, a carência de modelos de análise que auxiliem nos processos de gestão da cadeia de suprimentos e de seus elos, resultando processos baseados na experiência e na intuição, sem que variáveis relevantes, que exercem influência direta ou indireta ao longo do tempo nos resultados, tenham sido levadas em consideração. A principal proposta assim com a contribuição desta pesquisa foi o desenvolvimento e validação de uma metodologia para identificação de modelos mentais e sua conversão em diagramas causais, utilizando como base uma cadeia de suprimentos característica da indústria automobilística brasileira, pioneira na implantação do conceito de consórcio e condomínio modular. Para complementar este trabalho, foi desenvolvido através dos diagramas causais, em caráter exploratório, um modelo de simulação computadorizado que permite observar as respostas do sistema dado uma variação em uma de suas variáveis.

Desenho de mecanismo, incentivos e eficiência da cadeia produtiva

Existem muitos estudos voltados para a eficiência na cadeia de valor nas áreas de Operações e Cadeia de Suprimentos. Este estudo busca contribuir com uma análise do ponto de vista de Desenho de Mecanismos e Alinhamento de Incentivos frente aos interesses da cadeia de valor da General Motors do Brasil - GMB. Diante dos conceitos de Economia como assimetria de informação, racionalidade limitada e custo de agência, a proposta é mostrar como esses influenciam no atual mecanismo e nos incentivos que determinam o comportamento dos agentes dentro da cadeia, bem como o impacto nos resultados da empresa. Através da metodologia de estudo de caso, faço uma interpretação dos dados à luz dos conceitos de Economia e proponho um novo mecanismo que amenize a assimetria de informação do mecanismo existente e incentivos que reduzam os custos de agência. A expectativa é de que os agentes se tornem accountable por suas decisões em favor dos interesses da cadeia de valor, aumentando assim a sua eficiência.