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Submitted by FREDERIC CONRAD JANZEN null (fcjanzen@utfpr.edu.br) on 2016-11-13T01:59:49Z No. of bitstreams: 1 Positioning and vibration control of a flexible structure in slewing motion by applying Shape Memory Alloys.pdf: 10393447 bytes, checksum: 905f7c805c63133af1f576ad7ebbfd4b (MD5) / Approved for entry into archive by Juliano Benedito Ferreira (julianoferreira@reitoria.unesp.br) on 2016-11-17T18:09:27Z (GMT) No. of bitstreams: 1 janzen_fc_dr_bauru.pdf: 10393447 bytes, checksum: 905f7c805c63133af1f576ad7ebbfd4b (MD5) / Made available in DSpace on 2016-11-17T18:09:27Z (GMT). No. of bitstreams: 1 janzen_fc_dr_bauru.pdf: 10393447 bytes, checksum: 905f7c805c63133af1f576ad7ebbfd4b (MD5) Previous issue date: 2016-09-19 / Estruturas flexíveis com movimento de rastreamento tem sido encontradas com frequência cada vez maior em diversos tipos de aplicações, por serem mais eficientes do que suas concorrentes rígidas. O estudo desses sistemas é importante por conta das vibrações advindas da redução de massa das estruturas. Muitos trabalhos têm sido publicados apresentado técnicas de controle aplicadas na redução dos efeitos dessas vibrações. Vários trabalhos demonstram a aplicação de materiais inteligentes como atuadores para esse tipo de aplicação. Sendo assim, o presente trabalho apresenta uma proposta para o controle do posicionamento angular e da vibração de uma estrutura flexível em movimento de rastreamento. Para tal, atuadores compostos de um material inteligente conhecido como Liga com Memoria de Forma são empregados para o controle da vibração da estrutura flexível. Com relação ao controle, a técnica de controle conhecida como Equações de Ricatti Dependentes dos Estados (SDRE) é aplicada para o controle. Com o objetivo de analisar a dinâmica do sistema com o controle proposto considera-se a modelagem matemática do sistema e sua validação através do desenvolvido de um protótipo experimental. Simulações numéricas são realizadas para analisar a viabilidade do controle proposto e testes experimentais são realizados com a finalidade de validar o modelo teórico e a proposta de controle. / Flexible structures with slewing motion has been found with increasing frequency in various types of applications, because they are more efficient than their rigid competitors. The study of these systems is important because of the vibrations coming from the mass reduction of structures. Many works have been published presenting control techniques applied in reducing the effects of these vibrations. Several studies demonstrate the application of intelligent materials as actuators for this application. This paper presents a proposal for controlling the angular positioning and vibration of a flexible structure in slewing motion. For such compounds an intelligent actuator materials known as Shape Memory Alloy is employed to control the vibration of the flexible structure. To control the system, the control technique known as State Dependent Ricatti Equation (SDRE), is applied to the control. In order to analyse the dynamics of the system with the proposed control the mathematical modelling of the system is considered and its validation by developed an experimental prototype. Numerical simulations are carried out to analyse the viability of the control and experimental tests are performed in order to validate the theoretical model and the proposed control.

Motivation of this master‘s thesis is solution of practical problem of the newly developed slewing ring for tram Škoda, type: 15T. Next impulse for thesis creation was the possibility to extend product range of roller bearing ZKL. There is processed strain – stress analysis of bearing inner design making use the finite element method (FEM). Obtained results are compared with classic approach based on the Hertz theory. Important aim of this work is three main parameters optimal establishment: rolling element diameter, arrangement radius and number of rolling elements. Optimization job is realized by solutions of direct tasks with different parameters. With regard to necessity of detailed stress analysis and conservation of reasonable computational time it was chosen approach of combination global and local FEM model. It was used pre/postprocessor PATRAN and solver MARC for solution of strain and stress analysis. Analytic solution was accomplished in software EXCEL.

Dagens samhälle går mot en livsstil som präglas av möjligheter att göra allt fler hållbara val. För att minska koldioxidavtrycket krävs en fortsatt stabil omställning till förnyelsebara energikällor, i vilken vindkraften har en betydande roll. Det här projektet syftar till att, under statiska förhållanden, studera lagren i vindkraftverkens pitchsystem och deras prestation, att undersöka lastfördelningen mellan rullkropparna i lagren, samt att bestämma kontaktvillkoren mellan ytterring och rullkropp. Genom att anta kvasi-statisk belastning på rotorbladet under en rotation har lagrens lastfördelning beräknats. En förenklad modell genom finita elementmetoden har tagits fram där rullkropparnas styvhet modelleras på speciella kopplingselement, vilket förbrukar mindre beräkningstid men fortfarande ger ett korrekt resultat. Den största anledningen till utmattningsbrott hos lagren är lastens cykliska karaktär. Resultatet av beräkningen tyder på en ojämn fördelad belastning mellan rullkropparna där vissa rullkroppar ständigt upptar mer last än övriga. Dessutom har läget för maximala kontakttryck på rullkropparnas yta och hur det ändras med tiden beräknats. Lagret i vindkraftverkets pitchsystem kan tyckas relativt obetydligt jämfört med övriga komponenter, men en korrekt funktion av dessa är väsentlig för att uppnå en säker drift av vindkraftverken. Resultatet av denna studie belyser behovet av en alternativ lösning som är effektivare och optimerad för denna applikation. / The world today is heading towards a more sustainable lifestyle in every aspect ranging from the clothes worn, transportation and even energy generation. The change towards lowering the carbon footprint is a slow but steady process, in which the wind industry play a major role.The project’s aim is to study the behavior of the pitch bearing under constant wind load conditions, investigate the load distribution between the rolling elements in the bearing and finally to determine the contact conditions that exist between the raceways and the rollers. The bearing load is calculated by assuming a quasi-static loading as the blade completes one revolution. A simplified finite element model is then built where the stiffness of the rollers is modeled onto special connector elements, which consumes less computational resource and still delivers an accurate result.The cyclic nature of loading is one of the major source of fatigue failure of these bearings. The load distribution data suggests uneven loading of the rolling elements and how certain rollers in a particular position are always more heavily loaded than the others. The loading information is also used to map the position of maximum contact pressure on to the surface of the rollers and how it changes with time.At the first glance, the pitch bearing might appear relatively insignificant compared to rest of the components, but a proper functioning of these bearings is essential for safe operation of the WT (Wind Turbine). The results of this work have thrown light into the proficiency of these bearings and the need for an alternate solution that is more efficient and better optimized for this application.

This master`s thesis deals with the design of an offshore crane jib with maximal safe working load 80 tons and maximal radius 45 meters. The design consists of a design solution of the steel construction and a stress analysis of its FEM model, which was performed using NX I-deas software according to the requirements and specifications of the Huisman company. This thesis includes source materials for drawing documentation.

Forests represent one of the biggest terrestrial ecosystems of Earth, that can produce important raw renewable materials such as wood with the help of sun, air and water. To efficiently extract these raw materials, the tree harvesting process is highly mechanized in developed countries, meaning that advanced forestry machines are continuously used to fell, to process and to transport the logs and biomass obtained from the forests. However, working with these machines is demanding both mentally and physically, which are known factors to negatively affect operator productivity. Mental fatigue is mostly due to the manual operation of the on-board knuckleboom crane, which requires advanced cognitive work with two joystick levers, while the most serious physical strains arise from cabin vibrations. These vibrations are generated from knuckleboom crane vibrations as a result of aggressive manual operation. To enhance operator workload, well-being, and to increase productivity of the logging process, semi-automation functions are suggested, which are supervised automatic executions of specific work elements. Some of the related issues are addressed in the current thesis. Therefore, the content is divided into: (1) the design and development of a semi-automation function focused only on the base joint actuator (slewing actuator) of a knuckleboom crane, and (2) active vibration damping solutions to treat crane structure vibrations induced by the main lift cylinder (inner boom actuator). The considered reference machine is a downsized knuckleboom crane of a forwarder machine, which is used to pick up log assortments from a harvesting site. The proposed semi-automation function presented in the first part could be beneficial for operators to use during log loading/unloading scenarios. It consists from a closed-loop position control architecture, to which smooth reference slewing trajectories are provided by a trajectory planner that is automated via operator commands. The used trajectory generation algorithms are taken from conventional robotics and adapted to semi-automation context with proposed modifications that can be customizable by operators. Further, the proposed active vibration damping solutions are aimed to reduce vibrations of the knuckleboom crane excited by the inner boom actuator due to aggressive manual commands. First, a popular input shaping control technique combined with a practical switching logic was investigated to deal with the excited payload oscillations. This technique proved to be useful with a fixed crane pose, however it did not provide much robustness in terms of different link configurations. To tackle this problem an H2-optimal controller is developed, which is active in the pressure feedback-loop and its solely purpose is to damp the same payload oscillations. During the design process, operator commands are treated and explained from input disturbance viewpoint. All of the hypothesis throughout this thesis were verified with extensive experimental studies using the reference machine.

Testability is crucial in today’s complex industrial system on chips (SoCs), where sensitive on-chip analog voltages need to be measured. In such cases, an operational amplifier (opamp) is required to sufficiently buffer the signals before they can drive the chip pad and probe parasitics. A single-stage opamp offers an attractive choice since it is power efficient and eliminates the need for frequency compensation. However, it has to satisfy demanding specifications on its stability, input common mode range, output swing, settling time, closed-loop gain and offset voltage. In this work, the settling time performance of a conventional folded-cascode (FC) opamp is substantially improved. Settling time of an opamp consists of two major components, namely the slewing period and the linear settling period. In order to reduce the settling time significantly without incurring excessive area and power penalty, a prudent circuit implementation that minimizes both these constituents is essential. In this work, three different slew rate enhancement (SRE) circuits have been evaluated through extensive simulations. The SRE candidate providing robust slew rate improvement was combined with a current recycling folded cascode structure, resulting in lower slewing and linear settling time periods. Exhaustive simulations on a FC cascode amplifier with complementary inputs illustrate the effectiveness of these techniques in settling time reduction over all envisaged operating conditions.

The content of this thesis is the construction project of technological multifunctional building new locality Nitra the Slovak Republic. Individual points outline the project, which are dealt with in this thesis can be divided into subcategories, depending on the type of information provided. The first category can include items such as a technical report to the STP, which describes the basic information about the objects constructed building including the construction situation, location of the site including links to transport and technical infrastructure and rough timetable for the construction of all buildings. The second category can include no specific calculation and optimization outputs such as itemized budget polyfunctional house SO-07.03, drawing of the site including all buildings proposed site and their economic evaluation, sizing of utilities for supplying water and electricity construction site, design of building machines and mechanisms including determining the time of deployment, technological regulation for the implementation of monolithic roof structure, including financial balance sheets prepared by the deployment of slab formwork. The last category included in the thesis are legislative requirements that must be observed and kept in the course of the construction plan is constructed as a safety and health at work, including security risks drawn up, inspection and testing schedule for monolithic construction and a list of environmental risks that may arise during implementation.