Controle de posição com restrição à orientação de um Veículo Aéreo Não-Tripulado tipo Quadrirrotor

Quadrotors aircraft are composed by four propellers mounted on four engines on a cross or x disposition, and, in this structure, the engines on the same arm spin in the same direction and the other arm in the opposite direction. By rotating each helix generates vertical upward thrust. The control is done by varying the rotational speed of each motor. Among the advantages of this type of vehicle can cite the mechanical simplicity of construction, the high degree of maneuverability and the ability to have vertical takeoffs and landings. The modeling and control of quadrirrotores have been a challenge due to problems such as nonlinearity and coupling between variables. Several strategies have been developed to control this type of vehicle, from the classical control to modern. There are air surveillance applications where a camera is fixed on the vehicle to point forward, where it is desired that the quadrotor moves at a fixed altitude toward the target also pointing forward, which imposes an artificial constraint motion, because it is not desired that it moves laterally, but only forwards or backwards and around its axes . This restriction is similar to the naturally existing on robots powered by wheels with differential drive, which also can not move laterally, due to the friction of the wheels. Therefore, a position control strategy similar to that used in this type of robot could be adapted for aerial robots like quadrotor. This dissertation presents and discusses some strategies for the control of position and orientation of quadrotors found in the literature and proposes a strategy based on dynamic control of mobile robots with differential drive, called the variable reference control. The validity of the proposed strategy is demonstrated through computer simulations

Urbanização turística em ponta negra: relações de força e processos sociais no período de 1979-2009

This master thesis aimed to investigate how the power relations operating in the tourism social processes, have shaped the urbanization of Ponta Negra district, Natal, Rio Grande do Norte - RN. The study assumes that the production of space is the result of global phenomena individualized by local forces a process of glocalization. The method used was the case study. It used primary and secondary data and information were treated using the technique of content analysis. The urbanization of Ponta Negra is inserted in the context of global process triggered in the 1970s. The Park of Dunas and Costeira Highway (PD/VC) urbanization project marks the beginning of the Tourisms since 1979. The period in focus was 1979 to 2009. The tourism was dived into four major sections time: tourism in Natal before the Coastal Highway (1939-1979); Project Parque das Dunas / Coastal Highway to the first boom in domestic tourism (1979 - 1990); the internationalization of tourism (1991-2000) and, of first "boom" to "decline" of international tourism (2001-2009). Based on the historical evolution of the tourism were elected three different social processes, able to demonstrate how relations of social forces brought in space act on them and help shape the process of urbanization of the neighborhood in question: The removal of beach hut , the soccer field Botafogo Football Club and the skyscrapers . Finally, it should summarize the research identified interests and conflicts among the actors that form the thrust of spatial transformations: cultural conflicts resulting from the imposition of social practices that differ from the taste of native; clashes between different groups that reflect the duality between use value and exchange value; and interests in land values. In addition, demonstrated that the social relations that involve the production of the area are stimulated by deep-seated societal processes historically and camouflaged by market relations and a modern facade that the city has acquired in recent times; revealed that the actors are linked in networks to increase their influence and that this influence varies mainly according to economic and political power that they or their associates hold

Modelagem numérica de uma estrutura de contenção de estacas espaçadas atirantadas em areia

Retaining walls design involves factors such as plastification, loading and unloading, pre-stressing, excessive displacements and earth and water thrust. Furthermore, the interaction between the retained soil and the structure is rather complex and hard to predict. Despite the advances in numerical simulation techniques and monitoring of forces and displacements with field instrumentation, design projects are still based on classical methods, whose simplifying assumptions may overestimate structural elements of the retaining wall. This dissertation involves a three-dimensional numerical study on the behavior of a retaining wall using the finite element method (FEM). The retaining wall structure is a contiguous bored pile wall with tie-back anchors. The numerical results were compared to data obtained from field instrumentation. The influence of the position of one or two layers of anchors and the effects of the construction of a slab bounded at the top of the retaining wall was evaluated. Furthermore, this study aimed at investigating the phenomenon of arching in the soil behind the wall. Arching was evaluated by analyzing the effects of pile spacing on horizontal stresses and displacements. Parametric analysis with one layers of anchors showed that the smallest horizontal displacements of the structure were achieved for between 0.3 and 0.5 times the excavation depth. Parametric analyses with two anchor layers showed that the smallest horizontal displacements were achieve for anchors positioned in depths of 0.4H and 0.7H. The construction of a slab at the top of the retaining wall decreased the horizontal displacements by 0.14% times the excavation depth as compared to analyses without the slab. With regard to the arching , analyzes showed an optimal range of spacing between the faces of the piles between 0.4 and 0.6 times the diameter of the pile

Acompanhamento do crescimento e desenvolvimento da criança: a participação das mães da área rural

The accompaniment of growth and development is the central thrust of child care in primary health care in order to contribute to the reduction of infant morbidity and mortality and promote healthy development. Despite its importance, the family health unit located in rural Parazinhocounty experiences the problem of frequent absences of children to follow-up consultations. Thus, this study aims to analyze the participation of mothers in the accompaniment of growth and development of children in the Family Health Strategy. This is an exploratory, descriptive study with a qualitative approach with the method action research, developed with mothers who are part of the monitoring of the growth and development of children in the rural area of the municipality of Parazinho/RN from May to October 2014. Data collection was performed using the focus group techniques, participant observation and individual interviews. Data were analyzed using thematic analysis of categorization. The study was approved by the Research Ethics Committee, under the opinion embodied 617,559 and CAAE 28598014.7.0000.5537. In step situation analysis, were conducted two focus groups, attended by a total of 14 mothers of different rural locations. From the speeches, one realizes that they have a satisfactory understanding of the monitoring of the growth and development of the childwas a learning moment. The nurse was mentioned as key professional that actionof accompaniment. The main reason that mothers to abandon consultations is access to health services, due to the distance from their homes to the basic unit, the shortage of public transport for the movement of users and delay between the service and the back home. As a strategy to try to tackle these problems, at the suggestion of their mothers was created Monitoring of Growth and Development Itinerant, where the FHS team moved to rural locations, performing activities related to children's health. Mothers who participated in the action approved the initiative as improving access and care of health needs, despite indicate dissatisfaction as the poor infrastructure and little privacy in consultations. Therefore, it is concluded that, despite the difficulties encountered often for lack of management support and involvement of some professionals, the monitoring of growth and development itinerant proved to be an important tool in solving the problem of access to services oriented to the health of child, in addition to functioning as a space for the realization of health education, becoming, since then, an activity inherent in family health team schedule.

Estudo da evolução das tensões residuais através da difratometria de raios x em aço rolamento submetido a esforços cíclicos

The micro-deformations caused by cyclic loading origins the variation of the distances between atoms of the crystal lattice producing the irreversible component. In order to study and understand the microstructural behavior of the material this paper investigated the influence suffered by residual stresses in thrust rolling bearing races fabricated in AISI 52100 steel, after tests by cyclic rolling contact in a tribometer at 1m/s under two contact pressures (500 MPa and 1400 MPa) in dry and boundary lubrication conditions. Procedures of tests thermo-acustically isolated were developed for monitoring the contact temperature and sound pressure level signals to establish a comparison between the residual stress measurements, micro-hardness Vickers and micrographic registers searching an indication of wear evolution. The sin²ψ method by X-ray diffraction technique was used to quantify the residual stresses. Three raceway zones were selected for the evaluation of wear and surface morphology after predetermined cycling, comparing with their new condition ("as received"). Micro-hardness and residual stress measurements showed significant changes after the tests and it was possible to observe the relationship between the increase of sound pressure level and the residual stress for dry and lubricated conditions.

Estudo da evolução das tensões residuais através da difratometria de raios x em aço rolamento submetido a esforços cíclicos

The micro-deformations caused by cyclic loading origins the variation of the distances between atoms of the crystal lattice producing the irreversible component. In order to study and understand the microstructural behavior of the material this paper investigated the influence suffered by residual stresses in thrust rolling bearing races fabricated in AISI 52100 steel, after tests by cyclic rolling contact in a tribometer at 1m/s under two contact pressures (500 MPa and 1400 MPa) in dry and boundary lubrication conditions. Procedures of tests thermo-acustically isolated were developed for monitoring the contact temperature and sound pressure level signals to establish a comparison between the residual stress measurements, micro-hardness Vickers and micrographic registers searching an indication of wear evolution. The sin²ψ method by X-ray diffraction technique was used to quantify the residual stresses. Three raceway zones were selected for the evaluation of wear and surface morphology after predetermined cycling, comparing with their new condition ("as received"). Micro-hardness and residual stress measurements showed significant changes after the tests and it was possible to observe the relationship between the increase of sound pressure level and the residual stress for dry and lubricated conditions.