This bachelor thesis project in mechatronics involved making a working prototype of an automatic wire cutter and evaluating its accuracy. The accuracy of the machine was increased by analysing measurements of the machine’s initial precision and thereafter performing a calibration to diminish the eect of unwanted errors. Before calibration the machine’s accuracy was ± 0.73 cm and after calibration it was calculated to be ± 0.06 cm in its intended operating range of 5-20 cm. The main limitations of the machine’s accuracy were determined to be slippage in the feeding mechanism, the mathematical model that was used, the step resolution of the stepper motors, the oset between the blades in the cutting mechanism as well as the wires bending when being fed. / I detta kandidatexamnesarbete inom mekatronik designades och tillverkades en fungerande prototyp av en automatisk kabelklippare, och dess noggrannhet undersöktes sedan. Maskinens noggrannhet förbättrades genom att först undersöka maskinens ursprungliga noggrannhet och därefter kalibrerades maskinen för att minska effekten av oönskade fel. Före kalibrering var maskinens noggrannhet ± 0,73 cm och efteråt räknades den ut att vara ± 0,06 cm i dess tilltänkta driftintervall på 5-20 cm. De huvudsakliga begränsningarna för maskinens noggrannhet visade sig vara glidning i matningsmekanismen, den matematiska modellen, stegmotorns stegupplösning, avståndet mellan bladen i klippmekanismen samt att kablarna böjer sig under frammatning.

This thesis describes the development of an autonomous recovery system for stratospheric balloons, focusing on the novel pressurised balloon prototype BALMAN of CNES. Stratospheric balloons, reaching altitudes of up to 40 km, are utilised for scientific experiments, with recovery of payloads being a critical aspect. While traditional recovery methods involve separating the balloon envelope and deploying a parachute, BALMAN's parachute will be deployed in free fall. The proposed autonomous system comprises decision-making and electronics components. The decision-making segment employs microcontrollers and environmental sensors to recognise the balloon's descent, triggering the release decision. The electronics section, responsible for providing energy to a pyro cutter, is designed with electrical switches and capacitors. Thermal simulations guide the placement of heaters, maintaining system temperature within operational limits. The final prototype, tested for functionality on-ground, exhibits a measured energy release of 24 mJ, double the requirement for pyro cutter activation. However, environmental and flight testing remain pending. The system's potential applications extend beyond BALMAN, offering a standardised autonomous recovery solution for various balloons. This innovation promises enhanced landing accuracy, obviates the need for telecommunication in recovery, and facilitates payload descent deceleration. Future endeavors involve comprehensive testing and potential integration into BALMAN missions, showcasing the system's adaptability and operational simplicity across diverse stratospheric endeavors.

La performance des inserts d’outils tricône et des taillants d’outils PDC commerciaux est soumise au compromis dureté/ténacité principalement régi par la proportion de cobalt et la taille des grains de carbures cémentés WC-Co et du PDC. Les traitements de graduation basés sur l’imbibition de cobalt et les revêtements de nitrure de bore des carbures cémentés permettent d’augmenter la résistance à l’abrasion au niveau de la surface active des inserts et des taillants tout en générant une ténacité accrue au cœur des carbures cémentés. Des essais d’usure à l’aide d’un tribomètre rotatif avec une contreface en alumine pour les inserts WC-Co et à l’aide d’un tour d’usure avec une contreface en béton à forte teneur en silice pour les taillants ont permis d’étudier leur comportement tribologique. Pour les inserts, le coefficient de frottement et les cinétiques d’usure (modèle d’Archard), mais aussi l’évaluation de la température de contact et de l’émission acoustique générée au contact, ont permis de mieux comprendre l’effet des traitements réalisés sur les carbures cémentés. Pour les taillants PDC un modèle de qualité, basé sur un compromis usure/efficacité de coupe, a été développé afin de caractériser la résistance à l’usure des taillants. Des analyses physicochimiques (EDX, DRX, Raman) ont permis d’associer l’évaluation de la résistance à l’abrasion des échantillons à des mécanismes d’usure en considérant les éléments constitutifs des systèmes tribologiques et la formation de troisièmes corps. Les résultats ont ainsi montré l’importance de la proportion de cobalt générée dans les débits d’usure sur la stabilité des débris abrasifs (alumine et silice) et ainsi sur la résistance à l’usure des inserts et taillants. Les mécanismes de rupture des microstructures WC-Co et PDC sont aussi mis en avant afin d’expliquer leur influence sur la résistance à l’abrasion des échantillons. Enfin, des mesures de ténacité des inserts ont permis de juger de l’apport des traitements d’imbibition sur la résistance à la propagation de fissures des carbures cémentés WC-Co. Aussi, des essais complémentaires de chocs ont permis de montrer que les traitements améliorant la résistance à l’abrasion des taillants ne se traduisent pas par la chute de leur résistance aux chocs. / The performance of commercial tricone bit inserts and PDC bit cutters is defined by the compromise between hardness and fracture toughness controlled by the cobalt proportion and the grain size of WC-Co cemented carbide and PDC. On one hand, graduation treatments based on reactive imbibition of cobalt and boron nitride coating of cemented carbides lead to an improvement of abrasive wear resistance of inserts and cutters active surfaces. On the other hand, greater fracture toughness is obtained in the cemented carbides core as a result of imbibition. Wear experiments were performed with a rotary tribometer using an alumina contreface for the WC-Co inserts and with a lathe and its silica based concrete contreface for the PDC cutters. For the inserts, the friction coefficient and wear kinetics (Archard model), but also contact temperature measurement and acoustic emission consideration, permitted to clarify the treatments effects on cemented carbides tribological behaviour. For PDC cutters, a quality model, based on wear/cutting efficiency compromise, was developed in order to characterize the wear resistance. Physicochemical analyses (EDX, XRD, Raman) made a link between mechanical results and wear mechanisms considering the tribological systems and the third body formation. These analyses highlighted the influence of the proportion of cobalt generated in the wear flows on the stability of abrasive debris (alumina and silica) and thus on the wear resistance of inserts and cutters. The Fracture mechanisms of WC-Co and PDC microstructures have also been studied and their effects on the wear resistance have been demonstrated here. At last, fracture toughness measurements showed that the imbibition treatments could maintain a good resistance to cracks propagation of inserts. In addition, complementary impacts experiments prove that the improvement of wear resistance of PDC cutters did not produce reduction of impact strength

Formigas são insetos eusociais intensamente dependentes da comunicação química, possuindo características morfológicas, bioquímicas, fisiológicas e comportamentais adaptadas a um estilo de vida circundado por mensagens químicas. Esta peculiaridade olfativa do ponto de vista biológico, reflete nos padrões altamente polimórficos encontrados nas colônias dos grupos mais derivados, como as formigas cortadeiras (Attini). Assim, as castas e sub castas encontradas nos ninhos de formigas do gênero Atta, possuiriam características, como os órgãos olfativos e a sensibilidade eletrofisiológica, variáveis de acordo com seus tamanhos corpóreos e funções exercidas na colônia. Portanto, haveria uma correlação direta ou indireta do tamanho das formigas, os perfis comportamentais e comunicação química nessas espécies. Essa relação poderia ser vista em diversas atividades, como a limpeza entre os indivíduos e a troca de alimentos via oral. Dessa forma, a presente tese foca na interação entre o polimorfismo, polietismo e comunicação química nas formigas de Atta sexdens. Ainda descreve a participação das operárias e rainha nos comportamentos de grooming e trofalaxia, ligando-os à possível função de dispersão de hidrocarbonetos de cutícula na colônia. A tese esta dividida em quatro capítulos. O Capítulo 1, compreendeu uma introdução dos conhecimentos abordados em toda tese, e as linhas gerais do trabalho. No Capítulo 2, foi realizado uma descrição quantitativa e qualitativa das sensilas em todas as castas e sub castas encontradas em ninhos de A. sexdens. Os resultados indicaram que esses órgãos sensoriais variaram de acordo com os padrões polimórficos e perfis etológicos. O Capítulo 3 abordou as respostas eletrofisiológicas da antenas a diferentes feromônios, comparando todos os grupos polimórficos de A. sexdens. Foram observados neste caso, similaridades e discrepâncias na sensibilidade aos conteúdos das glândulas de veneno, Dufour e mandibular entre as sub castas (jardineiras, generalistas, forrageiras e soldados), e também entre os machos e rainhas, possibilitando a correlação com as atividades que exercem no ninho. No Capítulo 4 investigou-se a participação de cada tipo de operárias de A. sexdens nos comportamentos de trofalaxia, allogrooming e self-grooming, relacionando-os com a presença da rainha dentro da câmara. Adicionalmente, frente aos resultados, as diferentes ações das sub castas nesses comportamentos puderam ser associadas à possível importância da limpeza e troca de alimentos na dispersão de compostos de reconhecimento e formadores do gestalt químico da colônia. Estes resultados, contribuem para uma melhor compreensão do complexo cenário sustentado pela eusocialidade, ecologia química, percepção olfativa e comportamento nas formigas cortadeiras. / Ants are eusocial insects intensely dependent on chemical communication. They have morphological, biochemical, physiological and behavioral features adapted to a life surrounded by many molecules messages. Furthermore, each olfactory peculiarity in any of the biological level mentioned above, reflects on the highly polymorphic patterns found in the colonies of the most derived groups, as the leaf cutter ants (Attini). Thus, the castes and sub castes of Atta ants, would have characteristics, as olfactory organs and electrophysiological sensibility, that vary following the body sizes and tasks performed in the colonies. Therefore, it would have a direct or indirect correlation among the sizes of the ants, their ethological profiles and the chemical communication in these species. This relation could be seen over different activities, as the grooming and oral trophallaxis. In this way, this thesis focus in the interaction among the polymorphism, polyethism and chemical communication in Atta sexdens. It still describes the participation of workers and queen in grooming and trophallaxis, linking them to a possible role in cuticular hydrocarbon dispersion over the colony. The thesis is divided in four chapters. In the Chapter 1, it is presented an introduction to the knowledge explored in all thesis, and also its outline. In the Chapter 2, there is a quantitative and qualitative description of sensilla from all castes and sub castes of A. sexdens, showing that these sensory organs vary following the polymorphic patterns and ethological profiles. The Chapter 3 explores the differences in the antennae electrophysiological responses to three pheromones, comparing them with all polymorphic groups of A. sexdens. The results demonstrate similarities and discrepancies in the sensibility to the contents of poison, Dufour and mandibular glands among the sub castes (gardeners, generalists, foragers and soldiers), and also between males and queens, enabling a correlation with their tasks. In the Chapter 4, it is investigated the roles of each type of A. sexdens workers in the trophallaxis, allogrooming and self-grooming behaviors, relating them with the queen presence. Additionally, and based in the results, the different roles of the sub castes can be associated to a possible action of grooming and trophallaxis in the dispersion of intraspecific recognition molecules and in the formation of a colony chemical gestalt. All results and discussion distributed along the thesis, therefore, contribute to a better understanding of a complex scenario, supported by the eusociality, chemical ecology, olfactory perception and behavior of the leaf cutter ants.

<div>This dissertation addresses two significant issues in the effective application of machine learning algorithms and models for the physical and engineering sciences. The first is the broad challenge of automated modeling of data across different processes in a physical system. The second is the dilemma of obtaining insightful interpretations on the relationships between the inputs and outcome of a system as inferred from complex, black box machine learning models.</div><div><br></div><div><b>Automated Geometric Shape Deviation Modeling for Additive Manufacturing Systems</b></div><div><b><br></b></div><div>Additive manufacturing systems possess an intrinsic capability for one-of-a-kind manufacturing of a vast variety of shapes across a wide spectrum of processes. One major issue in AM systems is geometric accuracy control for the inevitable shape deviations that arise in AM processes. Current effective approaches for shape deviation control in AM involve the specification of statistical or machine learning deviation models for additively manufactured products. However, this task is challenging due to the constraints on the number of test shapes that can be manufactured in practice, and limitations on user efforts that can be devoted for learning deviation models across different shape classes and processes in an AM system. We develop an automated, Bayesian neural network methodology for comprehensive shape deviation modeling in an AM system. A fundamental innovation in this machine learning method is our new and connectable neural network structures that facilitate the transfer of prior knowledge and models on deviations across different shape classes and AM processes. Several case studies on in-plane and out-of-plane deviations, regular and free-form shapes, and different settings of lurking variables serve to validate the power and broad scope of our methodology, and its potential to advance high-quality manufacturing in an AM system.</div><div><br></div><div><b>Interpretable Machine Learning</b></div><div><b><br></b></div><div>Machine learning algorithms and models constitute the dominant set of predictive methods for a wide range of complex, real-world processes. However, interpreting what such methods effectively infer from data is difficult in general. This is because their typical black box natures possess a limited ability to directly yield insights on the underlying relationships between inputs and the outcome for a process. We develop methodologies based on new predictive comparison estimands that effectively enable one to ``mine’’ machine learning models, in the sense of (a) interpreting their inferred associations between inputs and/or functional forms of inputs with the outcome, (b) identifying the inputs that they effectively consider relevant, and (c) interpreting the inferred conditional and two-way associations of the inputs with the outcome. We establish Fisher consistent estimators, and their corresponding standard errors, for our new estimands under a condition on the inputs' distributions. The significance of our predictive comparison methodology is demonstrated with a wide range of simulation and case studies that involve Bayesian additive regression trees, neural networks, and support vector machines. Our extended study of interpretable machine learning for AM systems demonstrates how our method can contribute to smarter advanced manufacturing systems, especially as current machine learning methods for AM are lacking in their ability to yield meaningful engineering knowledge on AM processes. <br></div>

Mit dem zweidimensionalen numerischen Diskrete-Elemente-Programm UDEC wurde nach vorheriger Kalibrierung das Einstanzen einer keilförmigen Schneide in Gesteinsmaterial simuliert und mit Laborversuchen verglichen. Außerdem wurde ein Schneidprozess simuliert. Mittels einer selbst entwickelten Routine, welche die Gesteinselemente bei Überlastung zerteilt und ein ‚Re-meshing‘ erzeugt, konnten befriedigende Simulationsergebnisse erzielt werden. Mit der dreidimensionalen Simulationssoftware PFC3D auf Partikelbasis wurden Modelle mit Hilfe von Zug-, Druck-, Scher- und Stanzversuchen kalibriert und anschließend Schneid- und Bohrversuche simuliert. Die Schneidsimulationen erbrachten bezüglich der Kräfte bei verschiedenen Prozessparametern gute Übereinstimmung mit den Laborversuchen. Bei der Bohrsimulationen konnten Kräfte und Momente aus den Laborversuchen nur teilweise reproduziert werden.

Milling is a widely used cutting process, most commonly applied to machining external surfaces of workpieces. When machining operations are required within hard to reach areas of components, or deep within the bore of components, alternative methods of metal removal are generally employed. Typically when milling at extended reaches, difficulties may increase exponentially when trying to achieve distances several meters into a component. Essentially every topic of the milling process becomes difficult and more convoluted. Firstly to generate a stable cutting condition, and ultimately for an operator to be able to understand the cutting conditions, when all normal senses to interpret the machining stability are removed. The aim for the research is, to enable the operation of high slenderness ratio internal milling operations to become a viable technology, by detailing the measures required, to obtain a stable cutting condition. The process needs to be monitored for degradation of the tooling due to wear, and to prevent catastrophic machine damage from tool breakage or machine component failure. This research addresses the lack of knowledge available for milling with extended reaches, and the knowledge gained to overcome the real difficulties that exist for this process. Initial experiments are conducted on a prototype machine to gain experience of the internal machining operation and the many issues that it faced. Establishing requirements of the process via investigation of the tooling and necessary auxiliary equipment, it becomes possible to consider countermeasures to address the errors generated by torsional twisting of the milling arm. A system for applying a counter torque to reduce torsional deflection errors has been employed to successfully reduce the unavoidable issue over such long distances. For the process to become manageable for an industrial operator without a high level of specialist knowledge, the application of tool condition monitoring (TCM) and process condition monitoring (PCM) had to be applied. This addresses a void in available literature and research with respect to internal machining, and enables the process to become practical for an industrial environment. For this reason the research project will concentrate on the application of TCM and PCM onto the machining system. The completion of the research resulted in the process becoming satisfyingly stable, and with a resulting accuracy that satisfies the requirements of the component. Performance of the final system rivalled or achieved better results than had been experienced by the project sponsor.

Made available in DSpace on 2016-06-02T19:51:29Z (GMT). No. of bitstreams: 1 DissVV.pdf: 1066608 bytes, checksum: d0800dc87f0f2d12d19bc52bfd149f46 (MD5) Previous issue date: 2007-02-27 / The present research aimed understanding three variables existents in the manual sugar cane cut activity: workforce conditions, productivity and risks to the worker s health. To reach this objective it was necessary to observe, by the descriptive research, a serie of factors like the workforce conditions necessary to the rurals historical evolutions; the actual workforce conditions existent in this activity; the productivity reached in the activity; the workers health risk in the sugar cane cut activity; and under the research on field method, a case study that could show the the three variables working in a plant, which conclusion presents several visions taken by this variables comprehension. / O presente estudo tem por objetivo compreender três variáveis existentes na atividade do corte manual de cana: condições de trabalho, produtividade e riscos à saúde dos trabalhadores. Para que esse objetivo fosse atingido, foi necessário observar, através da pesquisa descritiva, uma série de fatores, tais como a evolução histórica das reivindicações dos trabalhadores rurais por melhores condições de trabalho; as atuais condições de trabalho existentes nessa atividade; a produtividade alcançada na atividade; os riscos à saúde dos trabalhadores na atividade do corte manual de cana, e, através do método de pesquisa de campo, a realização de um estudo de caso que pudesse expor as três variáveis em funcionamento no interior de uma usina, cuja conclusão apresenta diversas visões extraídas da compreensão de tais variáveis.

Made available in DSpace on 2016-06-02T19:51:45Z (GMT). No. of bitstreams: 1 3270.pdf: 2170334 bytes, checksum: 55c9d68d2cb5a404b6eef0f2c35e4c06 (MD5) Previous issue date: 2010-09-24 / Financiadora de Estudos e Projetos / The rural working activity subdues the worker to weather variations, the risk of venomous animals bites, sweating which leads to dehydration and most of all the intense muscular activity which causes damages to the physical structure and overload the worker which may lead him to death. These characteristics predicate the need of actions to maintain the health. Some measures are mandatory like the ones in the Regulatory Norm-31, and others, of free support like the ones mentioned in the National Commitment to Improve the Work Conditions of Sugar Cane Work. From the knowledge of the sugar cane cutting activity, the implications at the workers´ health, the information obtained through postural activity, pointed in photographic records and the Workplace Exercises view obtained through interviews with the rural workers and the responsible professionals for the Workplace Exercises, was found that the Workplace Exercises were held once a day, before the beginning of the sugar cane cutting activity in a site distant from the plantation, using multipliers for the purpose, through repetitive and monotonous exercises. Therefore, it was found that the Workplace Exercises is ineffective facing the characteristics encountered during the administration of it. / A atividade do corte de cana-de-açúcar sujeita o trabalhador às variações climáticas, ao risco de picadas de animais, à desidratação pela perda de água e sais minerais pelo suor e, sobretudo, à intensa atividade muscular, que causam danos à estrutura física e sobrecarregam o trabalhador, podendo levá-lo à morte. Essas características pressupõem a necessidade de ações que preservem a saúde. Algumas medidas são obrigatórias, como as citadas na Norma Regulamentadora-31, e outras, de livre adesão, como as mencionadas no Compromisso Nacional para Aperfeiçoar as Condições do Trabalho na Cana-de-açúcar. A partir do conhecimento da atividade do corte da cana-de-açúcar, as implicações a saúde do trabalhador, as informações obtidas por meio das análises posturais, evidenciadas pelos registros fotográficos e a visão da Ginástica Laboral, obtida pelas entrevistas, aos trabalhadores rurais e aos profissionais responsáveis pela Ginástica Laboral, verificou-se que a Ginástica Laboral é realizada uma vez ao dia, antes do início da atividade do corte, em um local distante da lavoura, utilizando multiplicadores para tal fim, por meio da aplicação de exercícios repetitivos e monótonos. Constatou-se, portanto, que Ginástica Laboral é ineficaz diante das características encontradas na aplicação da mesma.

Formigas são insetos eusociais intensamente dependentes da comunicação química, possuindo características morfológicas, bioquímicas, fisiológicas e comportamentais adaptadas a um estilo de vida circundado por mensagens químicas. Esta peculiaridade olfativa do ponto de vista biológico, reflete nos padrões altamente polimórficos encontrados nas colônias dos grupos mais derivados, como as formigas cortadeiras (Attini). Assim, as castas e sub castas encontradas nos ninhos de formigas do gênero Atta, possuiriam características, como os órgãos olfativos e a sensibilidade eletrofisiológica, variáveis de acordo com seus tamanhos corpóreos e funções exercidas na colônia. Portanto, haveria uma correlação direta ou indireta do tamanho das formigas, os perfis comportamentais e comunicação química nessas espécies. Essa relação poderia ser vista em diversas atividades, como a limpeza entre os indivíduos e a troca de alimentos via oral. Dessa forma, a presente tese foca na interação entre o polimorfismo, polietismo e comunicação química nas formigas de Atta sexdens. Ainda descreve a participação das operárias e rainha nos comportamentos de grooming e trofalaxia, ligando-os à possível função de dispersão de hidrocarbonetos de cutícula na colônia. A tese esta dividida em quatro capítulos. O Capítulo 1, compreendeu uma introdução dos conhecimentos abordados em toda tese, e as linhas gerais do trabalho. No Capítulo 2, foi realizado uma descrição quantitativa e qualitativa das sensilas em todas as castas e sub castas encontradas em ninhos de A. sexdens. Os resultados indicaram que esses órgãos sensoriais variaram de acordo com os padrões polimórficos e perfis etológicos. O Capítulo 3 abordou as respostas eletrofisiológicas da antenas a diferentes feromônios, comparando todos os grupos polimórficos de A. sexdens. Foram observados neste caso, similaridades e discrepâncias na sensibilidade aos conteúdos das glândulas de veneno, Dufour e mandibular entre as sub castas (jardineiras, generalistas, forrageiras e soldados), e também entre os machos e rainhas, possibilitando a correlação com as atividades que exercem no ninho. No Capítulo 4 investigou-se a participação de cada tipo de operárias de A. sexdens nos comportamentos de trofalaxia, allogrooming e self-grooming, relacionando-os com a presença da rainha dentro da câmara. Adicionalmente, frente aos resultados, as diferentes ações das sub castas nesses comportamentos puderam ser associadas à possível importância da limpeza e troca de alimentos na dispersão de compostos de reconhecimento e formadores do gestalt químico da colônia. Estes resultados, contribuem para uma melhor compreensão do complexo cenário sustentado pela eusocialidade, ecologia química, percepção olfativa e comportamento nas formigas cortadeiras. / Ants are eusocial insects intensely dependent on chemical communication. They have morphological, biochemical, physiological and behavioral features adapted to a life surrounded by many molecules messages. Furthermore, each olfactory peculiarity in any of the biological level mentioned above, reflects on the highly polymorphic patterns found in the colonies of the most derived groups, as the leaf cutter ants (Attini). Thus, the castes and sub castes of Atta ants, would have characteristics, as olfactory organs and electrophysiological sensibility, that vary following the body sizes and tasks performed in the colonies. Therefore, it would have a direct or indirect correlation among the sizes of the ants, their ethological profiles and the chemical communication in these species. This relation could be seen over different activities, as the grooming and oral trophallaxis. In this way, this thesis focus in the interaction among the polymorphism, polyethism and chemical communication in Atta sexdens. It still describes the participation of workers and queen in grooming and trophallaxis, linking them to a possible role in cuticular hydrocarbon dispersion over the colony. The thesis is divided in four chapters. In the Chapter 1, it is presented an introduction to the knowledge explored in all thesis, and also its outline. In the Chapter 2, there is a quantitative and qualitative description of sensilla from all castes and sub castes of A. sexdens, showing that these sensory organs vary following the polymorphic patterns and ethological profiles. The Chapter 3 explores the differences in the antennae electrophysiological responses to three pheromones, comparing them with all polymorphic groups of A. sexdens. The results demonstrate similarities and discrepancies in the sensibility to the contents of poison, Dufour and mandibular glands among the sub castes (gardeners, generalists, foragers and soldiers), and also between males and queens, enabling a correlation with their tasks. In the Chapter 4, it is investigated the roles of each type of A. sexdens workers in the trophallaxis, allogrooming and self-grooming behaviors, relating them with the queen presence. Additionally, and based in the results, the different roles of the sub castes can be associated to a possible action of grooming and trophallaxis in the dispersion of intraspecific recognition molecules and in the formation of a colony chemical gestalt. All results and discussion distributed along the thesis, therefore, contribute to a better understanding of a complex scenario, supported by the eusociality, chemical ecology, olfactory perception and behavior of the leaf cutter ants.