22 research outputs found

    About intelligent maintenance and diagnosis techniques for mechatronic systems : case study using fractional order calculus

    Get PDF
    Orientadores: João Maurício Rosário, José António Tenreiro MachadoTese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia MecânicaResumo: A competitividade no mercado global exige cada vez mais a fabricação de produtos de alta qualidade em curto tempo de fabricação, evitando tempos de parada para manutenção e reparo de máquinas e equipamentos, exigindo assim um eficiente controle de qualidade do processo e dos produtos para evitar a ocorrência de falhas de fabricação e utilização. A integração de novas tecnologias em produtos industriais (ex. tecnologias mecatrônicas) exige a utilização de técnicas avançadas para o diagnóstico de falhas, a partir de análise dos sinais obtidos a partir do sensoriamento dos equipamentos, minimizando assim os custos de utilização de mão de obra especializada para controle de qualidade do produto. Neste trabalho é apresentado inicialmente, um estudo sobre o estado da arte em técnicas de manutenção industrial, com ênfase nas estratégias utilizadas para manutenção corretiva, periódica e baseada no comportamento com ênfase no estudo das técnicas de processamento do sinal e identificação de sistemas, frequentemente utilizadas no diagnóstico de sistemas mecatrônicos, que exigem uma grande quantidade de informações, e forte dependência da análise criteriosa de um técnico especializado. Assim, neste trabalho são utilizados sistemas de ordem fracionária, que permite a aproximação do comportamento real do sistema por meio de modelos com menos coeficientes que o sistema real, simplificando a análise do sistema em estudo. Um estudo experimental de caso para validação do trabalho é realizado a partir de uma bancada experimental de um sistema de transmissão por engrenagens que permitiu introduzir falhas particulares no sistema e sua identificaçãoAbstract: The global market competitiveness requires to make high quality products in a short time of manufacturing, avoiding stop-times due to maintenance and repairing of machines and devices, therefore, demanding an efficient quality control of the manufacturing process, in order to shun failures in fabrication and utilization. The integration of new technologies into industrial products (e.g. mechatronics technologies) requires the use of advanced techniques to a precise failure diagnosis. They are typically based on signal analyses, which are obtained from the machines' instrumentation, and consequently, reduce the manpower costs associated to quality control of particular products. In this work it is introduced a literature review of industrial maintenance techniques, focusing in the strategies used into corrective, periodic and condition based maintenance, specially using signal processing and system identification. Those paradigms are frequently applied into the mechatronics systems diagnosis, but requires a huge amount of information and it is strongly dependent on the specialist criterion. In this sense, we introduced a fractional order system approach, which results in a better approximation of the actual system through an few parameters architecture, hence simplifying the analysis of the actual system. A real experimental setup was used to validate the strategies studied in this work. It consist in a gear transmission that lets to introduce particular failures for a posterior identificationDoutoradoMecanica dos Sólidos e Projeto MecanicoDoutor em Engenharia Mecânic

    Control de manipuladores teleoperados

    Get PDF
    This work is a bibliographical review about different models used to design teleoperated manipulator controllers, there is a quick description of some advantages and disadvantages to implement conventional or intelligent techniques (Neural Networks and Fuzzy Logic) to develop control systems applied to these devices. In addition, here the teleoperation systems are descriptively presented; finally there is a specialized section that shows some control strategies in order to deal with signal delays, inherent to manipulator teleoperation. In the last section some important applications for these systems are described.Este trabajo presenta una revisión bibliográfica acerca de distintos modelos utilizados en el diseño de controladores para manipuladores teleoperados, se realiza una descripción tanto de las ventajas como de los problemas que se presentan al momento de implementar sistemas de control con técnicas convencionales e inteligentes (Redes Neuronales y Lógica Difusa) en estos dispositivos. También se abordan descriptivamente los sistemas teleoperados, para finalmente presentar una sección especializada en la que se muestran estrategias de control empleadas para tratar los retardos de señal inherentes a la teleoperación de manipuladores. En la última sección se citan algunas aplicaciones importantes para estos sistemas

    Intelligent maintenance of complex systems: a fractional order approach

    Get PDF
    Compete in the global market requires high quality of products with short time of manufacture, so it needs to minimize the time that the machinery is stopped, as well as a rapid quality control of manufactured products. These process are achieved by maintenance strategies that are strongly based on the subjective knowledge of an expert. In this work we use the proficiency of the fractional order calculus to approximate complex behavior with a few parameter, providing a new tool for quickly health evaluation.N/

    Structural Damage detection and Reliability Estimation using a Multidimensional Monitoring Approach

    Get PDF
    Many structural elements are exposed to load conditions that are difficult to model during the design stage, such as environmental uncertainties, random impacts and overloading amongst others, thus, increasing un programmed maintenance and reducing confidence in the reliability of the structure in question -- One way to deal with this problem is to monitor the structural condition of the element -- This approach requires supervising several signals coming from critical locations and then, performing an accurate condition estimation of the element based on the data collected -- Herein, this paper implements a method to diagnosis and evaluate the reliability of the bolster beam structure of the railway-vehicle during a fatigue test -- The results show that multidimensional monitoring not only provides an accurate diagnosis of the element, but also that this technique allows to estimate reliability correctl

    Photography-based taxonomy is inadequate, unnecessary, and potentially harmful for biological sciences

    Get PDF
    The question whether taxonomic descriptions naming new animal species without type specimen(s) deposited in collections should be accepted for publication by scientific journals and allowed by the Code has already been discussed in Zootaxa (Dubois & Nemésio 2007; Donegan 2008, 2009; Nemésio 2009a–b; Dubois 2009; Gentile & Snell 2009; Minelli 2009; Cianferoni & Bartolozzi 2016; Amorim et al. 2016). This question was again raised in a letter supported by 35 signatories published in the journal Nature (Pape et al. 2016) on 15 September 2016. On 25 September 2016, the following rebuttal (strictly limited to 300 words as per the editorial rules of Nature) was submitted to Nature, which on 18 October 2016 refused to publish it. As we think this problem is a very important one for zoological taxonomy, this text is published here exactly as submitted to Nature, followed by the list of the 493 taxonomists and collection-based researchers who signed it in the short time span from 20 September to 6 October 2016

    Impact of COVID-19 on cardiovascular testing in the United States versus the rest of the world

    Get PDF
    Objectives: This study sought to quantify and compare the decline in volumes of cardiovascular procedures between the United States and non-US institutions during the early phase of the coronavirus disease-2019 (COVID-19) pandemic. Background: The COVID-19 pandemic has disrupted the care of many non-COVID-19 illnesses. Reductions in diagnostic cardiovascular testing around the world have led to concerns over the implications of reduced testing for cardiovascular disease (CVD) morbidity and mortality. Methods: Data were submitted to the INCAPS-COVID (International Atomic Energy Agency Non-Invasive Cardiology Protocols Study of COVID-19), a multinational registry comprising 909 institutions in 108 countries (including 155 facilities in 40 U.S. states), assessing the impact of the COVID-19 pandemic on volumes of diagnostic cardiovascular procedures. Data were obtained for April 2020 and compared with volumes of baseline procedures from March 2019. We compared laboratory characteristics, practices, and procedure volumes between U.S. and non-U.S. facilities and between U.S. geographic regions and identified factors associated with volume reduction in the United States. Results: Reductions in the volumes of procedures in the United States were similar to those in non-U.S. facilities (68% vs. 63%, respectively; p = 0.237), although U.S. facilities reported greater reductions in invasive coronary angiography (69% vs. 53%, respectively; p < 0.001). Significantly more U.S. facilities reported increased use of telehealth and patient screening measures than non-U.S. facilities, such as temperature checks, symptom screenings, and COVID-19 testing. Reductions in volumes of procedures differed between U.S. regions, with larger declines observed in the Northeast (76%) and Midwest (74%) than in the South (62%) and West (44%). Prevalence of COVID-19, staff redeployments, outpatient centers, and urban centers were associated with greater reductions in volume in U.S. facilities in a multivariable analysis. Conclusions: We observed marked reductions in U.S. cardiovascular testing in the early phase of the pandemic and significant variability between U.S. regions. The association between reductions of volumes and COVID-19 prevalence in the United States highlighted the need for proactive efforts to maintain access to cardiovascular testing in areas most affected by outbreaks of COVID-19 infection

    Congreso Internacional de Responsabilidad Social Apuestas para el desarrollo regional.

    Get PDF
    Congreso Internacional de Responsabilidad Social: apuestas para el desarrollo regional [Edición 1 / Nov. 6 - 7: 2019 Bogotá D.C.]El Congreso Internacional de Responsabilidad Social “Apuestas para el Desarrollo Regional”, se llevó a cabo los días 6 y 7 de noviembre de 2019 en la ciudad de Bogotá D.C. como un evento académico e investigativo liderado por la Corporación Universitaria Minuto de Dios -UNIMINUTO – Rectoría Cundinamarca cuya pretensión fue el fomento de nuevos paradigmas, la divulgación de conocimiento renovado en torno a la Responsabilidad Social; finalidad adoptada institucionalmente como postura ética y política que impacta la docencia, la investigación y la proyección social, y cuyo propósito central es la promoción de una “sensibilización consciente y crítica ante las situaciones problemáticas, tanto de las comunidades como del país, al igual que la adquisición de unas competencias orientadas a la promoción y al compromiso con el desarrollo humano y social integral”. (UNIMINUTO, 2014). Dicha postura, de conciencia crítica y sensibilización social, sumada a la experiencia adquirida mediante el trabajo articulado con otras instituciones de índole académico y de forma directa con las comunidades, permitió establecer como objetivo central del evento la reflexión de los diferentes grupos de interés, la gestión de sus impactos como elementos puntuales que contribuyeron en la audiencia a la toma de conciencia frente al papel que se debe asumir a favor de la responsabilidad social como aporte seguro al desarrollo regional y a su vez al fortalecimiento de los Objetivos de Desarrollo Sostenible

    Congreso Internacional de Responsabilidad Social Apuestas para el desarrollo regional.

    Get PDF
    Congreso Internacional de Responsabilidad Social: apuestas para el desarrollo regional [Edición 1 / Nov. 6 - 7: 2019 Bogotá D.C.]El Congreso Internacional de Responsabilidad Social “Apuestas para el Desarrollo Regional”, se llevó a cabo los días 6 y 7 de noviembre de 2019 en la ciudad de Bogotá D.C. como un evento académico e investigativo liderado por la Corporación Universitaria Minuto de Dios -UNIMINUTO – Rectoría Cundinamarca cuya pretensión fue el fomento de nuevos paradigmas, la divulgación de conocimiento renovado en torno a la Responsabilidad Social; finalidad adoptada institucionalmente como postura ética y política que impacta la docencia, la investigación y la proyección social, y cuyo propósito central es la promoción de una “sensibilización consciente y crítica ante las situaciones problemáticas, tanto de las comunidades como del país, al igual que la adquisición de unas competencias orientadas a la promoción y al compromiso con el desarrollo humano y social integral”. (UNIMINUTO, 2014). Dicha postura, de conciencia crítica y sensibilización social, sumada a la experiencia adquirida mediante el trabajo articulado con otras instituciones de índole académico y de forma directa con las comunidades, permitió establecer como objetivo central del evento la reflexión de los diferentes grupos de interés, la gestión de sus impactos como elementos puntuales que contribuyeron en la audiencia a la toma de conciencia frente al papel que se debe asumir a favor de la responsabilidad social como aporte seguro al desarrollo regional y a su vez al fortalecimiento de los Objetivos de Desarrollo Sostenible

    Control de manipuladores teleoperados

    No full text
    This work is a bibliographical review about different models used to design teleoperated manipulator controllers, there is a quick description of some advantages and disadvantages to implement conventional or intelligent techniques (Neural Networks and Fuzzy Logic) to develop control systems applied to these devices. In addition, here the teleoperation systems are descriptively presented; finally there is a specialized section that shows some control strategies in order to deal with signal delays, inherent to manipulator teleoperation. In the last section some important applications for these systems are describedEste trabajo presenta una revisión bibliográfica acerca de distintos modelos utilizados en el diseño de controladores para manipuladores teleoperados, se realiza una descripción tanto de las ventajas como de los problemas que se presentan al momento de implementar sistemas de control con técnicas convencionales e inteligentes (Redes Neuronales y Lógica Difusa) en estos dispositivos. También se abordan descriptivamente los sistemas teleoperados, para finalmente presentar una sección especializada en la que se muestran estrategias de control empleadas para tratar los retardos de señal inherentes a la teleoperación de manipuladores. En la última sección se citan algunas aplicaciones importantes para estos sistemas
    corecore