Proprioceptive force estimation and control for teleoperation in radioactive environments

A medida que se incrementa la energía de los aceleradores de partículas o iones pesados como el CERN o GSI, de los reactores de fusión como JET o ITER, u otros experimentos científicos, se va haciendo cada vez más imprescindible el uso de técnicas de manipulación remota para la interacción con el entorno sujeto a la radiación. Hasta ahora la tasa de dosis radioactiva en el CERN podía tomar valores cercanos a algunos mSv para tiempos de enfriamiento de horas, que permitían la intervención humana para tareas de mantenimiento. Durante los primeros ensayos con plasma en JET, se alcanzaban valores cercanos a los 200 μSv después de un tiempo de enfriamiento de 4 meses y ya se hacía extensivo el uso de técnicas de manipulación remota. Hay una clara tendencia al incremento de los niveles de radioactividad en el futuro en este tipo de instalaciones. Un claro ejemplo es ITER, donde se esperan valores de 450 Sv/h en el centro del toroide a los 11 días de enfriamiento o los nuevos niveles energéticos del CERN que harán necesario una apuesta por niveles de mantenimiento remotos. En estas circunstancias se enmarca esta tesis, que estudia un sistema de control bilateral basado en fuerza-posición, tratando de evitar el uso de sensores de fuerza/par, cuyo contenido electrónico los hace especialmente sensitivos en estos ambientes. El contenido de este trabajo se centra en la teleoperación de robots industriales, que debido a su reconocida solvencia y facilidad para ser adaptados a estos entornos, unido al bajo coste y alta disponibilidad, les convierte en una alternativa interesante para tareas de manipulación remota frente a costosas soluciones a medida. En primer lugar se considera el problema cinemático de teleoperación maestro-esclavo de cinemática disimilar y se desarrolla un método general para la solución del problema en el que se incluye el uso de fuerzas asistivas para guiar al operador. A continuación se explican con detalle los experimentos realizados con un robot ABB y que muestran las dificultades encontradas y recomendaciones para solventarlas. Se concluye el estudio cinemático con un método para el encaje de espacios de trabajo entre maestro y esclavo disimilares. Posteriormente se mira hacia la dinámica, estudiándose el modelado de robots con vistas a obtener un método que permita estimar las fuerzas externas que actúan sobre los mismos. Durante la caracterización del modelo dinámico, se realizan varios ensayos para tratar de encontrar un compromiso entre complejidad de cálculo y error de estimación. También se dan las claves para modelar y caracterizar robots con estructura en forma de paralelogramo y se presenta la arquitectura de control deseada. Una vez obtenido el modelo completo del esclavo, se investigan diferentes alternativas que permitan una estimación de fuerzas externas en tiempo real, minimizando las derivadas de la posición para minimizar el ruido. Se comienza utilizando observadores clásicos del estado para ir evolucionando hasta llegar al desarrollo de un observador de tipo Luenberger-Sliding cuya implementación es relativamente sencilla y sus resultados contundentes. También se analiza el uso del observador propuesto durante un control bilateral simulado en el que se compara la realimentación de fuerzas obtenida con las técnicas clásicas basadas en error de posición frente a un control basado en fuerza-posición donde la fuerza es estimada y no medida. Se comprueba como la solución propuesta da resultados comparables con las arquitecturas clásicas y sin embargo introduce una alternativa para la teleoperación de robots industriales cuya teleoperación en entornos radioactivos sería imposible de otra manera. Finalmente se analizan los problemas derivados de la aplicación práctica de la teleoperación en los escenarios mencionados anteriormente. Debido a las condiciones prohibitivas para todo equipo electrónico, los sistemas de control se deben colocar a gran distancia de los manipuladores, dando lugar a longitudes de cable de centenares de metros. En estas condiciones se crean sobretensiones en controladores basados en PWM que pueden ser destructivas para el sistema formado por control, cableado y actuador, y por tanto, han de ser eliminadas. En este trabajo se propone una solución basada en un filtro LC comercial y se prueba de forma extensiva que su inclusión no produce efectos negativos sobre el control del actuador. ABSTRACT As the energy on the particle accelerators or heavy ion accelerators such as CERN or GSI, fusion reactors such as JET or ITER, or other scientific experiments is increased, it is becoming increasingly necessary to use remote handling techniques to interact with the remote and radioactive environment. So far, the dose rate at CERN could present values near several mSv for cooling times on the range of hours, which allowed human intervention for maintenance tasks. At JET, they measured values close to 200 μSv after a cooling time of 4 months and since then, the remote handling techniques became usual. There is a clear tendency to increase the radiation levels in the future. A clear example is ITER, where values of 450 Sv/h are expected in the centre of the torus after 11 days of cooling. Also, the new energetic levels of CERN are expected to lead to a more advanced remote handling means. In these circumstances this thesis is framed, studying a bilateral control system based on force-position, trying to avoid the use of force/torque sensors, whose electronic content makes them very sensitive in these environments. The contents of this work are focused on teleoperating industrial robots, which due its well-known reliability, easiness to be adapted to these environments, cost-effectiveness and high availability, are considered as an interesting alternative to expensive custom-made solutions for remote handling tasks. Firstly, the kinematic problem of teloperating master and slave with dissimilar kinematics is analysed and a new general approach for solving this issue is presented. The solution includes using assistive forces in order to guide the human operator. Coming up next, I explain with detail the experiments accomplished with an ABB robot that show the difficulties encountered and the proposed solutions. This section is concluded with a method to match the master’s and slave’s workspaces when they present dissimilar kinematics. Later on, the research studies the dynamics, with special focus on robot modelling with the purpose of obtaining a method that allows to estimate external forces acting on them. During the characterisation of the model’s parameters, a set of tests are performed in order to get to a compromise between computational complexity and estimation error. Key points for modelling and characterising robots with a parallelogram structure are also given, and the desired control architecture is presented. Once a complete model of the slave is obtained, different alternatives for external force estimation are review to be able to predict forces in real time, minimizing the position differentiation to minimize the estimation noise. The research starts by implementing classic state observers and then it evolves towards the use of Luenberger- Sliding observers whose implementation is relatively easy and the results are convincing. I also analyse the use of proposed observer during a simulated bilateral control on which the force feedback obtained with the classic techniques based on the position error is compared versus a control architecture based on force-position, where the force is estimated instead of measured. I t is checked how the proposed solution gives results comparable with the classical techniques and however introduces an alternative method for teleoperating industrial robots whose teleoperation in radioactive environments would have been impossible in a different way. Finally, the problems originated by the practical application of teleoperation in the before mentioned scenarios are analysed. Due the prohibitive conditions for every electronic equipment, the control systems should be placed far from the manipulators. This provokes that the power cables that fed the slaves devices can present lengths of hundreds of meters. In these circumstances, overvoltage waves are developed when implementing drives based on PWM technique. The occurrence of overvoltage is very dangerous for the system composed by drive, wiring and actuator, and has to be eliminated. During this work, a solution based on commercial LC filters is proposed and it is extensively proved that its inclusion does not introduce adverse effects into the actuator’s control.

The souls of black folk : essays and sketches /

Of our spiritual strivings -- Of the dawn of freedom -- Of Mr. Booker T. Washington and others -- Of the meaning of progress -- Of the wings of Atalanta -- Of the training of black men -- Of the black belt -- Of the quest of the golden fleece -- Of the sons of master and man -- Of the faith of the fathers -- Of the passing of the first-born -- Of Alexander Crummell -- Of the coming of John -- The sorrow songs.

Letters from the East and from the West.

"The 'Letters from the East, or the valley of the Connecticut river,' were first published in the National intelligencer."--Pref. note.

The novels and other works of Lyof N. Tolstoï.

Editor's preface signed: Nathan Haskell Dole.

Fairy and folk tales of the Irish peasantry /

Variant issue: series title on half title; errata slip inserted at p. [ix].

Testimony taken before the committee appointed to make inquiry concerning the gas companies in the city and county of New York [electronic resource] : city of Buffalo, city of Brooklyn, and the city of Albany.

At head of title: State of New York.

Quadrature-phase noise penalties of optically and electro-optically phase-locked lasers

Focussing particularly on solid-state laser systems, the phase-noise penalties of laser injection-locking and electro-optical phase-locking are derived using linearised quantum mechanical models. The fundamental performance limit (minimum achievable output phase noise) for an injection-locked laser (IJL) system at low frequencies is equal to that of a standard phase-insensitive amplifier, whereas, in principle, that of a phase-locked laser (PLL) system can be better. At high frequencies, the output phase noise of the IJL system is limited by that of the master laser, while that of the PLL system tends to a weighted sum of contributions from the master and slave laser fields. Under conditions of large amplification, particularly where there has been significant attenuation, the noise penalties are shown to be substantial. Nonideal photodetector characteristics are shown to add significantly to the noise penalties for the PLL system. (C) 2005 Elsevier B.V. All rights reserved.

Consumer-identified barriers and strategies for optimizing technology use in the workplace

Purpose. This article explores the experiences of 26 assistive technology (AT) users having a range of physical impairments as they optimized their use of technology in the workplace. Method. A qualitative research design was employed using in-depth, open-ended interviews and observations of AT users in the workplace. Results. Participants identified many factors that limited their use of technology such as discomfort and pain, limited knowledge of the technology's features, and the complexity of the technology. The amount of time required for training, limited work time available for mastery, cost of training and limitations of the training provided, resulted in an over-reliance on trial and error and informal support networks and a sense of isolation. AT users enhanced their use of technology by addressing the ergonomics of the workstation and customizing the technology to address individual needs and strategies. Other key strategies included tailored training and learning support as well as opportunities to practice using the technology and explore its features away from work demands. Conclusions. This research identified structures important for effective AT use in the workplace which need to be put in place to ensure that AT users are able to master and optimize their use of technology.

Troilus and Cressida - A Scenic Design

The purpose of this thesis is to provide research, supporting paperwork, production photographs, and other materials that document the scenic design process for the production of William Shakespeare’s Troilus & Cressida by the University of Maryland – College Park, School of Theater, Dance, and Performance Studies. This thesis contains the following: scenic research images collected to express period, location, and emotional/intellectual landscapes to the production team; preliminary sketches; photographs of the ¼” scale model; a full set of drafting plates and paint elevations used to communicate the design to the technical director and paint charge; a unit list naming each scenic element; a props list and research book to detail each hand prop, furniture piece and consumable to the prop master; and, lastly, archival production photographs to document the completed design.

O processo de ensino-treinamento da tecnica e tatica no basquetebol do Brasil : um estudo sobe a otica de professores do ensino superior e tecnicos de elite

Universidade Estadual de Campinas . Faculdade de Educação Física

Inserção de graduados em fonoaudiologia de uma universidade pública em programas de pós-graduação

OBJETIVO: caracterizar a inserção de egressos do Curso de Fonoaudiologia da Universidade Estadual Paulista (UNESP) - Marília, em Programas de Pós-Graduação (PPG) Stricto Sensu brasileiros. MÉTODO: foram utilizadas listas de graduados e Curriculum Vitae do egresso e do orientador. RESULTADOS: dos 537 formados, 16,57% cursaram/estavam cursando PPG e destes, 98,88% em mestrado e 37,08% também em doutorado. Na grande área de conhecimento, 50% dos egressos de mestrado vincularam-se predominantemente a programas em Ciências da Saúde, 31,80% em Ciências Humanas e 13,64% em Linguística, Letras e Artes. No doutorado, 33, 33% em Ciências Humanas, 30,30% em Ciências da Saúde e em Linguística, Letras e Artes. Quanto à área de conhecimento, predominou a vinculação, no mestrado, de 30,68% em Fonoaudiologia, 28,41% em Educação, 13,64% em Linguística e 9,09% em Medicina I; e, no doutorado, de 33,33% em Educação, 30,30% em Linguística e 9,09% em Fonoaudiologia; 55,68% dissertações e 51,52% teses focalizaram a linguagem. A UNESP predominou com 39,77% no mestrado e 48,48% no doutorado. Predominou a vinculação a Programas com conceito 4 para 52,27% dos egressos do mestrado e 45,45% do doutorado. Quando constou a informação (55,68%), todos receberam fomento. O Teste de Razão de Verossimilhança não indicou diferenças significativas dos percentuais obtidos entre o mestrado e o doutorado. CONCLUSÃO: os resultados superaram os apresentados para o mesmo Estado, mostraram a característica interdisciplinar da Ciência Fonoaudiológica e o predomínio de temática em linguagem.

Paulo Mota Pinto: um jurista e político de mérito

Paulo Mota Pinto é licenciado, mestre e doutor em ciências jurídico-civilísticas pela Faculdade de Direito da Universidade de Coimbra. Assistimos às suas provas de Doutoramento em 16/1/2008: “Interesse Contratual Negativo e Interesse Contratual Positivo”. Abstract: Paulo Mota Pinto is licensed, Master and Doctor of Legal and Civil Sciences, Faculty of Law, University of Coimbra. Watched their PhD evidence 16/01/2008: "Interest Contract Contract Positive Negative Interest".

Phisiodata: desenvolvimento da evidência científica da fisioterapia em Portugal

Mestrado em Fisioterapia

Finge: relatório de estágio

Relatório de Estágio submetido à Escola Superior de Teatro e Cinema para cumprimento dos requisitos necessários à obtenção do grau de Mestre em Teatro, especialização em Artes Performativas - interpretação.

A função criativa do director de fotografia na fase de pós-produção na era digital: o caso português no biénio 2010/2011: dissertação

Dissertação submetida à Escola Superior de Teatro e Cinema para cumprimento dos requisitos necessários à obtenção do grau de Mestre em Desenvolvimento de projecto cinematográfico - Tecnologias de Pós-Produção