Embedded DSP-based compact fuzzy system and its application for induction motor V/F control

Este trabalho apresenta uma metodologia de implementação de algoritmos com estratégias fuzzy para sistemas embarcados em processadores digitais de sinais, cujo propósito de aplicação consiste no controle escalar de motores de indução trifásicos. A estratégia de controle adotada reside no ajuste da amplitude e freqüência (V/f) do sinal fundamental da tensão de alimentação do motor de indução, que foi modulado por largura de pulso aplicado a um inversor trifásico. Para tanto, o sistema de controle fuzzy foi integralmente embarcado em um processador digital de sinal empregando-se técnicas de simplificação que visam à redução dos requisitos de memória e custo computacional. O desempenho do controlador foi avaliado experimentalmente sob condições de variação de torque de carga aplicado ao eixo do motor de indução trifásico e referência de velocidade. Análises comparativas com as técnicas de controle PI e PID foram também realizadas com o propósito de validação da metodologia proposta.This paper presents a methodology for the implementation of embedded fuzzy system algorithms to be built in digital signal processors. For the purpose of this application, the technique was applied for induction motor scalar speed control. The adopted control strategy is to adjust the amplitude and frequency (V/f) of fundamental supply voltage signal of induction motor, which is achieved by a three-phase pulse width modulation inverter. The fuzzy control system was therefore entirely embedded in DSP by applying simplification techniques, which aim at computational cost and memory requirements reduction. The controller performance in relation to load torque and speed reference variations was evaluated by experimental tests. A comparative analysis with conventional PI and PID controllers was also achieved.FAPESPCNP

Narrativas de um Estudante Estagiário na subida da "Montanha" do Conhecimento da Educação Física

O Estágio Profissional pode ser entendido como a fase final da formação do Estudante Estagiário. É um percurso sinuoso constituído por dificuldades, alegrias e vitórias, que, no final do processo, constituem plenas e verdadeiras aprendizagens. Trata-se de um momento de transição de papéis, em que é abandonada a tradicional personagem de aluno, para se passar a adotar a de professor, com exigências e alunos reais. No presente documento, encontra-se plasmado todo percurso de um pedestriano (estudante-estagiário, o autor), desde o início da subida até à chegada ao cimo da "Montanha" do conhecimento da Educação Física. Este percurso acontece num agrupamento de escolas em Espinho, no distrito de Aveiro. O presente documento, de carater reflexivo, foi orientado por um docente da Faculdade de Desporto da Universidade do Porto e acompanhado por uma professora cooperante da escola onde o Estágio Profissional decorreu. Este relatório de estágio iniciou-se com a metáfora de um pedestriano, que durante o trilhar do ano letivo, vai adquirindo múltiplas aprendizagens fruto dos acontecimentos passados. Destaque-se a transformação ocorrida da passagem de aluno a professor, passando a atuar de forma planeada e cuidada, dando seguimento a um currículo pré-definido, na busca incessante de proporcionar as melhores aprendizagens a cada aluno. Acrescente-se o importante papel do processo de reflexão durante percurso de Estudante Estagiário, funcionando como elemento regulador na procura de melhores soluções e respostas, num percurso percorrido sem atalhos. Fruto desta perspetiva indagadora e reflexiva, emergiu a problemática da eficiência dos princípios da Avaliação para a Aprendizagem em aplicação na modalidade de Ginástica Acrobática. Da sua utilização, ficou evidente que os alunos aprenderam, sobretudo, nos momentos de Heteroavaliação, durante a apresentação, observação e avaliação dos esquemas gímnicos. Além disso, potenciou a aprendizagem ao nível do desempenho, do conhecimento e das dinâmicas de grupo. De facto, este foi um ano de verdadeira formação para o Estudante Estagiário, e a prova disso é o próprio documento.The school placement can be understood as the final stage of training of the student teacher. It is a winding journey constituted by difficulties, joys and victories that at the end of the process constitute full and true learnings. It is a moment of transition of roles, in which the traditional student role is abandoned, to start adopting the teacher role, with real demands and students. In this document, we find shaped, the entire journey of a pedestrian (preservice teacher, the author), since the beginning of the climb, until the arrival at the top of the "mountain" that is the knowledge of physical education. The school placement, takes place in a school of Espinho, in the district of Aveiro. This document that has a reflective finality, was supervised by a professor from the faculty of Sport, University of Porto and accompanied by a cooperating teacher from the school where the school placement took place. This internship report started with the metaphor of a pedestrian, who during the course of the school year, acquires multiple learnings as a result of past events. It's important to point the transformation that occurred from student for teacher, starting to act in a planned and careful way, following up on a pre-defined curriculum, in the relentless pursuit of providing the best learning to each student. Adding the reflection process during the Trainee Student journey, acting as a regulatory element in the search for better solutions and answers, on a journey that takes no shortcuts. As a result of this questioning and reflective perspective, the problem of the efficiency of the principles of Assessment for Learning emerged in application of the modality of Acrobatic Gymnastics. From its use, it was evident that the students learned, mainly, in the moments of Hetero-evaluation during the presentation, observation and evaluation of gymnastic schemes. In addition, it enhanced learning in terms of performance, knowledge and group dynamics. In fact, this was a year of real training for the Trainee Student, and the proof of this is the document itself

IMAGENS DA MULHER NA REVISTA VIDA CAPICHABA (1940-1949)

  This text examines images of women in Vida Capichaba, a biweekly magazine in circulation in the State of Espírito Santo (Brazil) between the decades of 1920 and 1950. It focuses on the issues published between 1940 and 1949, analyzing the social imperatives aimed at the instruction of women in Espírito Santo. It concludes that these imperatives were ambivalent (both conservative and subversive), with women-related sports and fashion playing a major role in the construction of new images and meanings of the feminine.Investiga imágenes de la mujer en la revista Vida Capichaba, publicación quincenal que circuló, en el Estado de Espírito Santo, entre las décadas de 1920 y 1950. El estudio se centra en las ediciones publicadas entre los años de 1940 hasta 1949. Analiza los imperativos sociales destinados a la formación de la mujer capixaba. Concluye que esos imperativos eran ambivalentes (al mismo tiempo conservadores y subversivos), siendo que la práctica deportiva y la moda estaban asociadas a ella como papel importante en la construcción de nuevas imágenes y sentidos del femenino.  Investiga imagens da mulher na revista Vida Capichaba, periódico de publicação quinzenal que circulou, no Estado do Espírito Santo, entre as décadas de 1920 e 1950. Tem como foco as edições publicadas entre os anos de 1940 e 1949. Analisa os imperativos sociais destinados à formação da mulher capixaba. Conclui que esses imperativos eram ambivalentes (ao mesmo tempo conservadores e subversivos), tendo a prática esportiva e a moda a ela associada papel importante na construção de novas imagens e sentidos do feminino.

Intelligent System for the Estimation of Gases Dissolved in Insulating Mineral Oil from Physicochemical Tests

The objective of this work was to make the modeling through artificial neural networks of the gas concentrations dissolved in insulating mineral oil from the results of physicochemical tests. In this case, a mapping between the data of physicochemical tests and gas chromatography was obtained by means of artificial neural networks. The proposed approach proved to be efficient to identify the amount of gases, taking the following attributes as input: color degree, density, dielectric rigidity, interfacial tension, power factor of the insulating oil, neutralization index, and water level. In addition, artificial neural networks provide not only a new methodology to support decisions but also satisfactory results comparatively to actual analyses when referring to the estimation of gases

On the application of intelligent systems for fault diagnosis in induction motors

Muitas pesquisas estão sendo desenvolvidas buscando nos sistemas inteligentes soluções para diagnosticar falhas em máquinas elétricas. Estas falhas envolvem desde problemas elétricos, como curto-circuito numa das fases do estator, ate problemas mecânicos, como danos nos rolamentos. Dentre os sistemas inteligentes aplicados nesta área, destacam-se as redes neurais artificiais, os sistemas fuzzy, os algoritmos genéticos e os sistemas híbridos, como o neuro-fuzzy. Assim, o objetivo deste artigo é traçar um panorama geral sobre os trabalhos mais relevantes que se beneficiaram dos sistemas inteligentes nas diferentes etapas de análise e diagnóstico de falhas em motores elétricos, cuja principal contribuição está em disponibilizar diversos aspectos técnicos a fim de direcionar futuros trabalhos nesta área de aplicação

Development of distributed control architecture for multi-robot systems

The execution of complex tasks by teams of robots has been widely investigated in the last decades, since many operations are too risky or difficult to be performed by humans or by a single robot. The complexity and variety of applications of mobile robotics make the coordination of teams a big problem, as several topologies of control systems, from simple single processes to large networks with distributed elements that are capable of switching function, may be necessary. Although simple solutions exist, more efficient approaches use distributed communication architectures and components abstraction layers. Available proposals provide many components and interfaces, complicating their understanding and operation. This paper presents a generic control architecture that provides the developer with a small amount of elements implemented safely and on high-performance libraries. The simplicity and modularity of the proposal allow implementation of features such as control of heterogeneous robots, data source and command destination transparency and platform and language independence. The ability to support with reliability, transparency and ease the development of various scenarios of autonomous mobile robotics make the proposed architecture a powerful and valuable tool in the design and operation of these systems.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Centro de Tecnologia da Informação Renato Arche

Estimation of bearing fault severity in line-connected and inverter-fed three-phase induction motors

Producción CientíficaThis paper addresses a comprehensive evaluation of a bearing fault evolution and its consequent prediction concerning the remaining useful life. The proper prediction of bearing faults in their early stage is a crucial factor for predictive maintenance and mainly for the production management schedule. The detection and estimation of the progressive evolution of a bearing fault are performed by monitoring the amplitude of the current signals at the time domain. Data gathered from line-fed and inverter-fed three-phase induction motors were used to validate the proposed approach. To assess classification accuracy and fault estimation, the models described in this paper are investigated by using Artificial Neural Networks models. The paper also provides process flowcharts and classification tables to present the prognostic models used to estimate the remaining useful life of a defective bearing. Experimental results confirmed the method robustness and provide an accurate diagnosis regardless of the bearing fault stage, motor speed, load level, and type of supply.CAPES (process BEX552269/2011-5)National Council for Scientific and Technological Development (grant #474290/2008-3, #473576/2011-2, #552269/2011-5, #307220/2016-8

Uma abordagem usando redes neurais artificiais para resolução de problemas de otimização restrita

Systems based on artificial neural networks have high computational rates due to the use of a massive number of simple processing elements and the high degree of connectivity between these elements. Neural networks with feedback connections provide a computing model capable of solving a large class of optimization problems. This paper presents a novel approach for solving constrained optimization problems using artificial neural networks. More specifically, a modified Hopfield network is developed and its internal parameters are computed using the valid-subspace technique. These parameters guarantee the convergence of the network to the equilibrium points, which represent the feasible solutions to problem. Simulated examples are presented to demonstrate the validity of the proposed method.Sistemas baseados em redes neurais artificiais fornecem altas taxas de computação devido ao uso de um número massivo de elementos processadores simples. Redes neurais com conexões realimentadas fornecem um modelo computacional capaz de resolver uma rica classe de problemas de otimização. Este artigo apresenta uma nova abordagem para resolver problemas de otimização restrita utilizando redes neurais artificiais. Mais especificamente, uma rede de Hopfield modificada é desenvolvida cujos parâmetros internos são calculados usando a técnica de subespaço válido de soluções. A partir da obtenção destes parâmetros a rede tende a convergir aos pontos de equilíbrio que representam as possíveis soluções para o problema. Exemplos de simulação são apresentados para justificar a validade da abordagem proposta.28530

How long does it take to translate research findings into routine healthcare practice? : the case of biological drugs for rheumatoid arthritis in Brazil

Background: The literature reports long time lags between the several processes involved in the translation of drug research and development into clinical application. To expedite these processes, translational research has emerged as a process that can be applied to reduce the lag between scientific discoveries and their practical application. Thus, the objective of this study was to estimate the time lag in translational research of biological drugs for the treatment of rheumatoid arthritis included in the Brazilian Unified Health System [Sistema Único de Saúde (SUS)]. Methods: A descriptive retrospective study was conducted based on secondary data loaded by SUS users in public sources and systems to estimate the time lag between the publication of phase I clinical trial results to drug use in clinical settings. The dates of translational research activities were identified from markers and steps. Structured searches were conducted in the literature and reports from the National Commission for the Incorporation of Technologies in the SUS (Conitec) as well as from health authorities, and analyzed. Results: Between 2012 and 2019, SUS included five biological agents for the treatment of rheumatoid arthritis. The mean time lag from clinical development to use of these agents was 11.13 years (range, 8.57 to 12.90 years). The mean time lag for the stages of translational research were 5.30 (T1—basic research to clinical research), 5.08 (T2—clinical research to research synthesis), and 0.75 (T3—research synthesis to evidence-based practice) years. A shorter time lag was observed in the Brazilian case when it was possible to compare with other studies. Conclusions: The estimated time lag of biological drugs used in the treatment of rheumatoid arthritis was determined based on the translational research steps model adapted to the Brazilian context. Brazil has instituted legal frameworks that set deadlines for sanitary registration, health technology assessment (HTA), and the availability of drugs in the SUS, thus, allowing for a reduced stage T2 time lag. Nevertheless, improvements are still required in stages T1 and T2, especially in publishing the results of clinical trials