<p> Of greatest interest in the field of linear motion electrical machines are, the flat linear induction motor and liquid metal pump. The former has feasibility in high speed transportation while the latter is becoming of increasing importance in metallurgical processes. </p> <p> This thesis examines and extends the traditional representation for the usual sheet secondary classification and then presents a common theory which also allows composite secondary machines to be analysed. An idealized model is developed consisting of a number of regions representing air gaps, iron segments, and secondary conductors. A general solution for the field quantities is obtained. The concept of wave impedance and a transfer matrix approach allow a wide variety of configurations to be analysed. Unlike previous work the approach developed here allows for simultaneous investigation of lateral variation and skin effect. In the limiting cases where in tum skin effect and lateral variation are neglected the solutions are in agreement with known results. </p> / Thesis / Master of Engineering (MEngr)

Paul Hindemith was one of the most distinguished composers of the twentieth century. This thesis will begin with biographical information, highlighting important events in his life. Then, in an effort to understand his compositional style and his philosophy of Gebrauchsmusik, his mastery of classical form, the Sonata for Clarinet and Piano is chosen for a detailed stylistic analysis. Treated in the analysis chapter are form, melody, harmony, rhythm, dynamic, and the technically problematic areas involved such as fingering and ensemble with piano. Hindemith's musical style is conservative in form and tonality. Tonality and melodic motives constitute the dominant force throughout the entire sonata. In the analysis of harmony in this study, Hindemith's own analytical method, which he established on acoustical phenomenon, will be employed as is necessary

Proper positioning of Microelectromechanical Systems (MEMS) components influences the functionality of the device, especially in devices where the motion is in the range of hundreds of micrometers. There are two main obstacles to positioning: off-axis displacement, and position determination. This work studies four large-displacement devices, their axial and transverse stiffness, and piezoresistive response. Methods for improving the device characteristics are described. The folded-beam suspension, small X-Bob, large X-Bob and double X-Bob were characterized using non-dimensional metrics that measure the displacement with regard to the size of the device, and transverse stiffness with regard to axial stiffness. The stiffness in each direction was determined using microprobes to induce displacement, and microfabricated force gauges to determine the applied force. The large X-Bob was optimized, increasing the transverse stiffness metric by 67%. Four-point resistance testing and microprobes were used to determine the piezoresistive response of the devices. The piezoresistive response of the X-Bob was maximized using an optimization routine. The resulting piezoresistive response was over seven times larger than that of the initial design. Piezoresistive encoders for ratcheting actuation of large-displacement MEMS are introduced. Four encoders were studied and were found to provide information on the performance of the ratcheting actuation system at frequencies up to 920 Hz. The PMT encoder produced unique signals corresponding to distinct ideal and non-ideal operation of the ratchet wheel actuation system. Encoders may be useful for future applications which require position determination.

No description available.

Detta examensarbete har utförts i samarbete med Z-lyften Produktion AB som tillverkar bakgavellyftar till lastbilar. En av deras modeller har funktionen att den kan köras in under lastbilen eller trailern. Lyften rullar då på hjul i så kallad slädprofiler som i sin tur är fästa mot lastbilen med ramfästen. Dessa profiler är i dagsläget tillverkade i stål och dimensionerade efter lasterna i arbetsläget vilket gör att de är överdimensionerade över resten av dess längd. Detta gör dem onödigt tunga. De är också svåra att kapa till olika längder och det finns en önskan att göra ramfästena flyttbara. Syftet med detta arbete blev därför att minska profilens vikt och därmed ge miljö- och arbetsmäss-iga vinster, göra fästena flyttbara för enklare montage på lastbil samt medge enklare kapning för effektivare produktion. Målet var att genom en produktutvecklingsprocess presentera ett koncept i form av en 3D-modell på en ny konstruktion av åkprofilen som uppfyller ovan nämnda syfte. En förstudie gav en överblick av konkurrensen och samtal med intres-senter gav en omfattande produktspecifikation att utgå ifrån i det fortsatta arbetet. Produktens önskade funktioner analyserades och dellösningar till dessa söktes sedan i ett antal källor. Detta ledde fram till en rad lös-ningar som kombinerades till fyra koncept varav ett valdes ut för detaljkonstruktion som utfördes med analytiska och numeriska beräk-ningar. Det slutgiltiga konceptet bestod i en aluminiumprofil med spår för flyttbara fästen och glidlager av plast i stället för hjul. Konceptet gav enligt en uppskattning en viktbesparing på 20% jämfört med den nuvarande och profilen i sig blev 60% lättare. Kostnadsmässigt gav själva profilen en besparing på 13% men totalt riskerar konceptet att bli dyrare än den ursprungliga lösningen då förstärkningar av stål behövs i arbetsläget. / This thesis is written in cooperation with Z-lyften Produktion AB which is a manufacturer of tail lifts for trucks. One of their models works by enabling the operator to stow the tail lift under the truck or trailer. The tail lift is in this case mounted on wheel brackets with steel wheels that rolls inside slide profiles. The slide profiles are mounted to the truck frame. Currently, these profiles are made from steel, and they are dimensioned to withstand the loads that are present when the lift is in operation. Therefore, the slide profiles are excessively dimensioned across the length except where the wheels are positioned during operation which causes them to be unnecessarily heavy. The steel profile is difficult to cut in production and there is also a desire to have mounting brackets that can be positioned more freely on the profile. Regarding this, the purpose of this work was to make the profiles lighter to reduce the environmental impact as well as improve the working environment in the production facility, make the mounting brackets more flexible to make the mounting process easier and to make the cutting process easier. The goal was to provide the company with a concept in the form of a 3D-model that fulfils the above purpose. A feasibility study provided an overview of the competition and meetings with stakeholders gave the comprehensive list of product specifications that was the foundation for the rest of the process. The desired functions of the product were analysed and solutions to the functions was then gathered from several sources. The identified possible solutions were then combined into four concepts of which one concept was selected for further development and dimensioning with analytical and numerical methods. The final concept is based on an extruded aluminium profile with polymer slide bearings and T-shaped slots for the mounting brackets. A rough estimate pointed to a weight saving of about 20% for the concept as a whole and the slide profiles alone was 60% lighter. The new profiles gave a cost reduction of 13% but the concept as a whole runs the risk of becoming more expensive than the current solution. / <p>2022-07-01</p>

Linear-motion compliant mechanisms have generally been developed for small displacement applications. The objective of the thesis is to provide a basis for improved large-displacement linear-motion compliant mechanisms (LLCMs). One of the challenges in developing large-displacement compliant mechanisms is the apparent performance tradeoff between displacement and off-axis stiffness. In order to facilitate the evaluation, comparison, and optimization of the performance of LLCMs, this work formulates and presents a set of metrics that evaluates displacement and off-axis stiffness. The metrics are non-dimensionalized and consist of the relevant characteristics that describe mechanism displacement, off-axis stiffness, actuation force, and size. Displacement is normalized by the footprint of the device. Transverse stiffness is normalized by a new performance characteristic called virtual axial stiffness. Torsional stiffness is normalized by a performance characteristic called the characteristic torque. Because large-displacement compliant mechanisms are often characterized by non-constant axial and off-axis stiffnesses, these normalized stiffness metrics are formulated to account for the variation of both axial and off-axis stiffness over the range of displacement. In pursuit of mechanisms with higher performance, this work also investigates the development of a new compliant mechanism element. It presents a pseudo-rigid-body model (PRBM) for rolling-contact compliant beams (RCC beams), a compliant element used in the RCC suspension. The loading conditions and boundary conditions for RCC beams can be simplified to an equivalent cantilever beam that has the same force-deflection characteristics as the RCC beam. Building on the PRBM for cantilever beams, this paper defines a model for the force-deflection relationship for RCC beams. Included in the definition of the RCC PRBM are the pseudo-rigid-body model parameters that determine the shape of the beam, the length of the corresponding pseudo-rigid-body links and the stiffness of the equivalent torsional spring. The behavior of the RCC beam is parameterized in terms of a single parameter defined as clearance, or the distance between the contact surfaces. The RCC beams exhibit a unique force-displacement curve where the force is inversely proportional to the clearance squared. The RCC suspension is modeled using the newly defined PRBM. The suspension exhibits unique performance, generating no resistance to axial motion while providing significant off-axis stiffness. The mechanism has a large range of travel and operates with frictionless motion due to the rolling-contact beams. In addition to functioning as a stand-alone linear-motion mechanism, the RCC suspension can be configured with other linear mechanisms in superposition to improve the off-axis stiffness of other mechanisms without affecting their axial resistance.

This research revolves around the concept design and theoretical validation of a new type of wave energy converter (WEC), comprising a pitching floater integrated with a resonant U-tank (RUT) and a Wells turbine as power take-off (PTO). Theoretical formulation of a fully coupled multi-body dynamic system, incorporating the thermodynamic processes of the RUT air chamber, its interaction with the PTO dynamics and their coupling with the floater is presented. Inaccuracies of the dynamic modeling of RUT based on Lloyd's low order model, which assumes constant hydrodynamic parameters irrespective of the frequency, are demonstrated by a series of high fidelity CFD simulations. These simulations are a systematic series of fully viscous turbulent simulations, using unsteady RANSE solvers, of the water sloshing at different frequencies of oscillation. Calibration of Lloyd’s model with CFD results evidenced that the RUT hydrodynamic parameters are not invariant to frequency. A numerical model was developed based on Simulink WEC-Sim libraries to solve the non-linear thermo-hydrodynamic equations of the device in time domain. For power assessment, parametric investigations are conducted by varying the main dimensions of the RUT and power RAOs were computed for each iteration. Performance in irregular sea state are assessed using a statistical approach with the assumption of linear wave theory. By superimposing spectrum energy density from two resource sites with RAO, mean annual energy production (MEAP) are computed. The predicted MEAP favorably compares with other existing devices, confirming the superior efficiency of the new proposed device over a larger range of incident wave frequency. / M.S. / This study present results of an investigation into a new type of wave energy converter which can be deployed in ocean and by its pitch response motion, it can harvest wave energy and convert it to electrical energy. This device consist of a floater, a U-tank (resonant U-tank) with sloshing water free to oscillate in response to the floater motion and a pneumatic turbine which produces power as air is forced to travel across it. The pneumatic turbine is used as the power take-off (PTO) device. A medium fidelity approach was taken to carry out this study by applying Lloyd’s model which describes the motion of the sloshing water in a resonant U-tank. Computational fluid dynamics (CFD) studies were carried out to calibrate the hydrodynamic parameters of the resonant U-tank as described by Lloyd and it was discovered that these parameters are frequency dependent, therefore Lloyd’s model was modelled to be frequency dependent. The mathematical formulation coupling the thermodynamic evolution of air in the resonant U-tank chamber, modified Lloyd’s sloshing water equation, floater dynamics and PTO were presented for the integrated system. These set of thermo-hydrodynamic equations were solved with a numerical model developed using MATLAB/Simulink WEC-Sim Libraries in time domain in other to capture the non-linearity arising from the coupled dynamics. To assess the annual energy productivity of the device, wave statistical data from two resource sites, Western Hawaii and Eel River were selected and used to carrying out computations on different iterations of the device by varying the tank’s main dimensions. This results were promising with the most performing device iteration yielding mean annual energy production of 579 MWh for Western Hawaii.

This master thesis deals with the construction of multi-functional machining centre. The theoretical part describes the history of lathes, trends in production of lathes and individual machine parts. The practical part is the structural design of the spindle with positioning in the C axis, the second spindle (including drive in Z axis) and the turret (including drive in the X and Z axis). A 3-D model of the entire lathe assembly modeled in Autodesk Inventor 2010 is also included.

Vehicle simulators are often built from scratch, using well-established software frameworks with custom vehicle models. Since the development of a simulator is a very time consuming process,  the purpose of this thesis paper was to explore a different alternative by evaluating the open-source vehicle system ChaosVehicle (CV) in Unreal Engine 5. The goal was to build a simulator using CV and assess its performance in imitating certain aspects of a three-wheeled electric vehicle, including acceleration, coasting and braking behaviors in a straight line.The simulator was set up according to the data provided by the vehicle manufacturer, OMotion. By comparing the simulations with real world driving data, it was determined that the simulator achieved a relative error below 16% in imitating the coasting behavior of the real vehicle. Further, with regards to the brake performance, the simulator has managed to achieve a relative error of below 15% when not accounting for velocities below 10 km/h. Due to the noise present in the real world driving data, it was inconclusive as to whether the simulator had accurately predicted the acceleration behavior of the  real vehicle. After a preliminary analysis of the plugin, it was discussed whether CV was as extensible as hypothesized. While the framework is open-source, it was difficult to fully grasp the system due to incomplete documentation of the source code and the user interface. Further work in mapping how the physics model in CV is integrated to the game engine would shed some light on this matter.

生活中在使用相機時，由於機器晃動或物體移動所造成的模糊影像時常可見。當影像模糊的成因是影像曝光時間內相機與拍攝物體相對線性移動時，則我們稱為線性動態模糊。理論上，模糊影像可以表示成原始影像與點擴散函數的旋積，本文的研究重點為點擴散函數中模糊參數的估計，雷登轉換將被運用在此問題上。我們首先介紹兩個現有方法，我們將探討這些方法中用來消除雜訊的步驟之適用性及必要性。另一方面，在模糊參數的估計過程中，我們在雷登轉換加入圓限制以及採用移動平均法。我們透過實驗證實，本篇提出的方法可以獲得更準確的估計結果以及更好的模糊影像還原效果。 / Nowadays, collecting a digital image becomes convenient and low-cost due to rapid progress in digital camera technology. Blurred images frequently appear because of camera shake or moving objects. There are several different types of blur. When the blur is caused by the linear motion between the object and the camera during the light exposure, it’s called a linear motion blur. Mathematically, a blurred image is expressed as a convolution of a point spread function and the original image. Our study considers Radon transform for the estimation of the point spread function. To improve the existing methods, a circle restriction and the moving average method are applied in the estimating procedure. Through intensive experiments, the proposed method is found enable to produce more accurate estimation and better performance in image restoration.