147 resultados para Servo
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"Navpers 91915[-91916]"
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"NAVPERS 92390."
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A identidade do Servo de YHWH sempre foi um grande desafio para a pesquisa bíblica. Quem seria esse Servo? Não se pretende saber historicamente quem foi o Servo de YHWH, pois isso é uma tarefa impossível. Pretende-se levantar algumas pistas a partir do contexto histórico e do próprio texto do Dêutero-Isaías que permita pensar na possibilidade de que uma comunidade exilada na Babilônia fosse chamada de Servo e destinada por YHWH para tal missão. Na perícope de Is 42,1-9, YHWH convoca o Servo para uma missão bem específica: fazer sair o direito para as nações. Esse direito que o Servo fará sair às nações é o direito de YHWH que se manifesta na libertação concreta de todos os encarcerados. O Servo com suas posturas silenciosas e proféticas, com sua prática solidária aos sofredores e com sua tenacidade, levará adiante esse projeto de libertação. Por meio dos procedimentos exegéticos e com referencial teórico de diferentes autores que já pesquisaram sobre esse tema, pretende-se investigar a possibilidade de que neste cântico do Servo de YHWH possa nascer uma Teologia do Servo que está em profunda sintonia com o Ser do próprio YHWH. Desta maneira, YHWH - Servo carregam um mesmo projeto concreto de libertação que tem como fundamento o direito e a justiça. Surge, então, no meio do povo sofrido, um novo modelo de liderança política.
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Traditional machinery for manufacturing processes are characterised by actuators powered and co-ordinated by mechanical linkages driven from a central drive. Increasingly, these linkages are replaced by independent electrical drives, each performs a different task and follows a different motion profile, co-ordinated by computers. A design methodology for the servo control of high speed multi-axis machinery is proposed, based on the concept of a highly adaptable generic machine model. In addition to the dynamics of the drives and the loads, the model includes the inherent interactions between the motion axes and thus provides a Multi-Input Multi-Output (MIMO) description. In general, inherent interactions such as structural couplings between groups of motion axes are undesirable and needed to be compensated. On the other hand, imposed interactions such as the synchronisation of different groups of axes are often required. It is recognised that a suitable MIMO controller can simultaneously achieve these objectives and reconciles their potential conflicts. Both analytical and numerical methods for the design of MIMO controllers are investigated. At present, it is not possible to implement high order MIMO controllers for practical reasons. Based on simulations of the generic machine model under full MIMO control, however, it is possible to determine a suitable topology for a blockwise decentralised control scheme. The Block Relative Gain array (BRG) is used to compare the relative strength of closed loop interactions between sub-systems. A number of approaches to the design of the smaller decentralised MIMO controllers for these sub-systems has been investigated. For the purpose of illustration, a benchmark problem based on a 3 axes test rig has been carried through the design cycle to demonstrate the working of the design methodology.
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A servo-controlled automatic machine can perform tasks that involve synchronized actuation of a significant number of servo-axes, namely one degree-of-freedom (DoF) electromechanical actuators. Each servo-axis comprises a servo-motor, a mechanical transmission and an end-effector, and is responsible for generating the desired motion profile and providing the power required to achieve the overall task. The design of a such a machine must involve a detailed study from a mechatronic viewpoint, due to its electric and mechanical nature. The first objective of this thesis is the development of an overarching electromechanical model for a servo-axis. Every loss source is taken into account, be it mechanical or electrical. The mechanical transmission is modeled by means of a sequence of lumped-parameter blocks. The electric model of the motor and the inverter takes into account winding losses, iron losses and controller switching losses. No experimental characterizations are needed to implement the electric model, since the parameters are inferred from the data available in commercial catalogs. With the global model at disposal, a second objective of this work is to perform the optimization analysis, in particular, the selection of the motor-reducer unit. The optimal transmission ratios that minimize several objective functions are found. An optimization process is carried out and repeated for each candidate motor. Then, we present a novel method where the discrete set of available motor is extended to a continuous domain, by fitting manufacturer data. The problem becomes a two-dimensional nonlinear optimization subject to nonlinear constraints, and the solution gives the optimal choice for the motor-reducer system. The presented electromechanical model, along with the implementation of optimization algorithms, forms a complete and powerful simulation tool for servo-controlled automatic machines. The tool allows for determining a wide range of electric and mechanical parameters and the behavior of the system in different operating conditions.