968 resultados para Posicionamento dos apoios


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Sob o acrônimo BOP (Bottom of Pyramid), muito se tem discutido sobre as vantagens empresariais de atender a uma classe emergente de aproximadamente 4 bilhões de pessoas ao redor do mundo (Prahalad 2005), como uma das formas de se defender da estagnação do consumo nos países mais desenvolvidos. Se hoje a discussão já está mais bem delineada, é muito em função de artigos de estudiosos como Prahalad, Hammond e Yunus que colocaram a base da pirâmide no centro do debate. Há empresas referência mundial nessa transição de atendimento para o BOP, como a GE na China ou a Unilever na Índia. Mas para o caso brasileiro, parece ainda não haver igual expressão, sendo a emergência do BOP mais recente. Algumas dessas empresas orientadas para as classes emergentes têm mudado seu modelo de negócios. Outras criam submarcas voltadas às classes emergentes e sofrem os impactos dessas decisões sobre a arquitetura de marcas. E, finalmente, há empresas que utilizam um conjunto de signos e códigos de comunicação na oferta de seus produtos e serviços que acreditam ser bem aceitos transversalmente nas classes sociais. O objetivo geral da dissertação foi avaliar quais códigos e signos de comunicação as empresas com posicionamento premium devem utilizar numa comunicação com essa classe emergente, sem correr o risco de afastar seu público-alvo original (das classes AB). O método inclui a ferramenta denominada Value Reframing (Reenquadramento de Valor), para a busca de novos valores para um produto ou serviço em um novo contexto de mercado. Tal ferramenta não prevê teste de rejeição dentro do público original. Então foram coletados: 1) os valores mais bem aceitos pela nova classe média; 2) os valores avaliados e não rejeitados por consumidores da classe AB. Em conclusão, é possível utilizar signos e códigos com aceitação nas duas classes (como uso do humor nas mensagens ou a sensação de que a mensagem foi direcionada para a pessoa). A adoção desses elementos podem ser mais bem sucedidos se acompanhados de uma discussão sobre o modelo de negócios vigente, para atender melhor a nova classe média.

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In this work, the variable structure adaptive pole placement controller (VS-APPC) robustness and performance are evaluated and this algorithm is applied in a motor control system. The controller robustness evaluation will be done through simulations, where will be introduced in the system the following adversities: time delay, actuator response boundeds, disturbances, parametric variation and unmodeled dynamics. The VS-APPC will be compared with PI control, pole placement control (PPC) and adaptive pole placement controller (APPC). The VS-APPC will be simulated to track a step and a sine reference. It will be applied in a three-phase induction motor control system to track a sine signal in the stator reference frame. Simulation and experimental results will prove the efficiency and robustness of this control strategy

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This dissertation dea1s with the active magnetic suspension controI system of an induction bearingIess motor configured with split windings. It analyses a dynamic modeI for the radial magnetic forces actuating on the rotor. From that, it proposes a new approach for the composition of the currents imposed to the machine's stator. It shows the tests accomplished with a prototype, proving the usefulness of the new actuating structure for the radial positioning controI. Finnaly, it points out the importance of adapting this structure to well-known rotational controI techniques, continuing this kind of equipment research, which is carried out at Federal University of Rio Grande do Norte since 2000

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This work proposes a method to localize a simple humanoid robot, without embedded sensors, using images taken from an extern camera and image processing techniques. Once the robot is localized relative to the camera, supposing we know the position of the camera relative to the world, we can compute the position of the robot relative to the world. To make the camera move in the work space, we will use another mobile robot with wheels, which has a precise locating system, and will place the camera on it. Once the humanoid is localized in the work space, we can take the necessary actions to move it. Simultaneously, we will move the camera robot, so it will take good images of the humanoid. The mainly contributions of this work are: the idea of using another mobile robot to aid the navigation of a humanoid robot without and advanced embedded electronics; chosing of the intrinsic and extrinsic calibration methods appropriated to the task, especially in the real time part; and the collaborative algorithm of simultaneous navigation of the robots

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There are two main approaches for using in adaptive controllers. One is the so-called model reference adaptive control (MRAC), and the other is the so-called adaptive pole placement control (APPC). In MRAC, a reference model is chosen to generate the desired trajectory that the plant output has to follow, and it can require cancellation of the plant zeros. Due to its flexibility in choosing the controller design methodology (state feedback, compensator design, linear quadratic, etc.) and the adaptive law (least squares, gradient, etc.), the APPC is the most general type of adaptive control. Traditionally, it has been developed in an indirect approach and, as an advantage, it may be applied to non-minimum phase plants, because do not involve plant zero-pole cancellations. The integration to variable structure systems allows to aggregate fast transient and robustness to parametric uncertainties and disturbances, as well. In this work, a variable structure adaptive pole placement control (VS-APPC) is proposed. Therefore, new switching laws are proposed, instead of using the traditional integral adaptive laws. Additionally, simulation results for an unstable first order system and simulation and practical results for a three-phase induction motor are shown

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In the last decade, the renewable energy sources have present a major propulsion in the world due to several factors: political, environmental, financial and others. Within this context, we have in particular the energy obtained through wind, wind energy - that has highlighted with rapid growth in recent years, including in Brazil, mostly in the Northeast, due to it s benefit-cost between the clean energies. In this context, we propose to compare the variable structure adaptive pole placement control (VS-APPC) with a traditional control technique proportional integral controller (PI), applied to set the control of machine side in a conversion system using a wind generator based on Double-Fed Induction Generator (DFIG). Robustness and performance tests were carried out to the uncertainties of the internal parameters of the machine and variations of speed reference.

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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In the past few years the interest is accomplishing a high accuracy positioning increasing. One of the methods that has been applied by the scientific community is the network based on positioning. By using multiple reference station data, it is possible to obtain centimetric positioning in a larger coverage area, in addition to gain in reliability, availability and integrity of the service. Besides, using this concept, it is possible to model the atmospheric effects (troposphere refraction and ionosphere effect). Another important question concerning this topic is related to the transmission of the network corrections to the users. There are some possibilities for this fact and an efficient one is the Virtual Reference Station (VRS) concept. In the VRS concept, a reference station is generated near to the rover receiver (user). This provides a short baseline and the user has the possibility of using a single frequency receiver to accomplish the relative positioning. In order to test this kind of positioning method, a software has been developed at São Paulo State University. In this paper, the methodology applied to generate the VRS data is described and the VRS quality is analyzed by using the Precise Point Positioning (PPP) method.

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)