Self-bearing machines for kinetic energy storage have the advantage of integrating the magnetic bearing in the stator/rotor configuration, which reduces the number of mechanical components needed compared with using separated active magnetic bearings. This master's thesis focus on building a MATLAB/Simulink simulation model for a self-bearing cone-shaped Lorenz-type electrical machine. The concept has already been verified analytically but no dynamic simulations have been made. The system was modeled as a negative feedback system with PID controllers to balance the rotor. Disturbances as signal noise, external forces and torques were added to the system to estimate system robustness. Simulations showed stability and promising dynamics, the next step would be to build a prototype.

This master thesis studies how much the cycle time, i.e. the time it takes for an industrial robot to perform a given task, can be reduced if an extra degree of freedom (DOF) is added to the robot system. The extra DOF consists of a linear track, which is supposed to be used in an optimal way. The problem has been studied using simulations in the robot simulation tool RobotStudio. To be able to run an optimization in Matlab, with the RobotStudio simulation cycle time as the object function, communication between Matlab and RobotStudio has been set up with an interface written in Visual Basic. An algorithm has been developed to solve the problem. Two different optimization methods have been examined and compared. The resulting algorithm has been applied to test cases. The results show that the cycle time in several cases can be reduced by 20-30 percent, if the movements along the track are optimized with the suggested method.

The failed anchoring systems of mobile offshore drilling units from hurricanes occurring in 2004 and 2005 established a need to better understand the ultimate pullout capacity and trajectory of scaled model anchors under typical and out-of-plane loading conditions. The six degrees of freedom of small scale drag embedment anchors were studied in a laboratory testing environment with the intent that reasonable trends in anchor behavior will be found. Investigations within this experimental research program demonstrated the in-plane and out-of-plane loading behavior of conventional and prototype scaled model anchors embedded to predetermined depths in two different test beds of kaolinite clay with undrained shear strength profiles constant and increasing with depth. The anchors were loaded to failure in concentric, normal, concentric, shear, eccentric, normal, eccentric, shear, inclined, and drag embedment loading configurations. This series of pullout and drag embedment tests provided a suite of test results indicating behavioral trends of the varying holding capacities and anchor trajectories. Results were compared with similar research presented in the literature and an analytical model predicting out-of-plane loading behavior of similar anchors. It was concluded that increasing eccentricities from both concentric, normal and concentric, shear loading configurations resulted in decreasing bearing capacity factors, confirming the predicted trend from the analytical model for these loading configurations. Trajectories observed for the concentric, normal, concentric, shear, and eccentric, shear loading configurations showed that the anchors tracked straight out of the soil without deviation, but eccentric, normal loading found the anchor tending to track away from the initial loading location. For inclined loads, both anchors to track to whichever direction the anchor faced upon loading. Drag embedment trajectory was found to vary depending on the anchor, as the conventional anchor dove with an applied load and the prototype anchor rose towards the surface. / text

This thesis describes an assessment of offshore wind farms using a Matlab tool Marine System simulator. This tool helps to analyse the Vessel motion according to different wave heights. From this assessment one can know the correct weather window for offshore operation and other possible techniques to reduce the time delay in operation. This tool is used to simulate a supply vessel motion according to different wave heights. The chosen supply vessel is the default supply vessel in the simulator.

abstract: Humans are capable of transferring learning for anticipatory control of dexterous object manipulation despite changes in degrees-of-freedom (DoF), i.e., switching from lifting an object with two fingers to lifting the same object with three fingers. However, the role that tactile information plays in this transfer of learning is unknown. In this study, subjects lifted an L-shaped object with two fingers (2-DoF), and then lifted the object with three fingers (3-DoF). The subjects were divided into two groups--one group performed the task wearing a glove (to reduce tactile sensibility) upon the switch to 3-DoF (glove group), while the other group did not wear the glove (control group). Compensatory moment (torque) was used as a measure to determine how well the subject could minimize the tilt of the object following the switch from 2-DoF to 3-DoF. Upon the switch to 3-DoF, subjects wearing the glove generated a compensatory moment (Mcom) that had a significantly higher error than the average of the last five trials at the end of the 3-DoF block (p = 0.012), while the control subjects did not demonstrate a significant difference in Mcom. Additional effects of the reduction in tactile sensibility were: (1) the grip force for the group of subjects wearing the glove was significantly higher in the 3-DoF trials compared to the 2-DoF trials (p = 0.014), while the grip force of the control subjects was not significantly different; (2) the difference in centers of pressure between the thumb and fingers (ΔCoP) significantly increased in the 3-DoF block for the group of subjects wearing the glove, while the ΔCoP of the control subjects was not significantly different; (3) lastly, the control subjects demonstrated a greater increase in lift force than the group of subjects wearing the glove (though results were not significant). Combined together, these results suggest different force modulation strategies are used depending on the amount of tactile feedback that is available to the subject. Therefore, reduction of tactile sensibility has important effects on subjects' ability to transfer learned manipulation across different DoF contexts. / Dissertation/Thesis / M.S. Bioengineering 2014

Neste trabalho aborda-se o desenvolvimento de um elemento finito de membrana com graus de liberdade rotacionais e sua implementação a um sistema computacional em elementos finitos. O trabalho é baseado na formulação livre de BERGAN & NYGARD (1984) que produz um elemento simples e de bom desempenho. Aspectos fundamentais da formulação livre, do desenvolvimento do elemento e sua implementação ao sistema são apresentados. Resultados obtidos em alguns exemplos comprovam a eficiência do procedimento. / In this work the formulation of a membrane finite element with rotational degrees of freedom and its implementation to a finite element computational system is presented. The development is based on the free formulation of BERGAN & NYGARD (1984) that produce a simple and efficient element. Fundamental aspects of the free formulation, of the element evaluation and its implementation to the system are shown. The results obtained in some examples indicate the accuracy of the procedure.

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This thesis focuses on the design of linear precoding schemes for downlink multiple-input multiple-output (MIMO) networks. These schemes are designed to be amenable to implementation in wireless networks that allow rate-limited feedback of channel state information (CSI). In the first half of this thesis, memoryless quantization codebooks are designed and incremental vector quantization techniques are developed for the representation of CSI in MIMO point-to-point links and isolated (single-cell) downlink networks. The second half of the thesis seeks to design linear precoding schemes for the multi-cell downlink networks that can achieve improved performance without requiring significantly more communication resources for CSI feedback than those required in the case of an isolated single-cell. For the quantization problem, smooth optimization algorithms are developed for the design of codebooks that possess attractive features that facilitate their implementation in practice in the addition to having good quantization properties. As one example, the proposed approach is used to design rank-2 codebooks that have a nested structure and elements from a phase-shift keying (PSK) alphabet. The designed codebooks have larger minimum distances than some existing codebooks, and provide tangible performance gains. To take advantage of temporal correlation that may exist in the wireless channel, an incremental approach to the Grassmannian quantization problem is proposed. This approach leverages existing codebooks for memoryless quantization schemes and employs a quantized form of geodesic interpolation. Two schemes that implement the principles of the proposed approach are presented. A distinguishing feature of the proposed approach is that the direction of the geodesic interpolation is specified implicitly using a point in a conventional codebook. As a result, the approach has an inherent ability to recover autonomously from errors in the feedback path. In addition to the development of the Grassmannian quantization techniques and codebooks, this thesis studies linear precoder design for the downlink MIMO networks in the cases of small networks of arbitrary topology and unbounded networks that have typical architectures. In particular, a linear precoding scheme for the isolated 2-cell network that achieves the optimal spatial degrees of freedom of the network is proposed. The implementation of a limited feedback model for the proposed linear precoding scheme is developed as well. Based on insight from that model, other linear precoding schemes that can be implemented in larger networks, but with finite size, are developed. For unbounded networks of typical architecture, such as the hexagonal arrangement of cells, linear precoding schemes that exploit the partial connectivity of the network are presented under a class of precoding schemes that is referred to as spatial reuse precoding. These precoding schemes provide substantial gains in the achievable rates of users in the network, and require only local feedback. / Thesis / Doctor of Philosophy (PhD)

京都大学 / 新制・課程博士 / 博士(工学) / 甲第24576号 / 工博第5082号 / 新制||工||1973(附属図書館) / 京都大学大学院工学研究科建築学専攻 / (主査)教授 大崎 純, 教授 竹脇 出, 教授 聲高 裕治 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DFAM

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