The implementation of automated systems in manufacturing industries increases efficiency, precision, and safety by reducing human intervention, errors, and waste. Variable loads can cause several problems for automation systems. One of the most significant challenges is maintaining the stability and precision of the production process despite changing load conditions. These variable loads can lead to unstable systems or failures, causing an increase in errors, reduced efficiency, and lower product quality. It is essential to design control systems that can adapt to changing load conditions and maintain stable and precise operation under all circumstances. To address this problem, this thesis presents an adaptive controller based on load identification and gain scheduling, to replace the standard FOC consisting of regular PI-controllers. The load estimator is used to estimate the external load with relatively small RMSD values, while the ain scheduler adjusts the controller gains based on the estimated load. Other controllers are also explored, such as an angular velocity error-based adaptive controller. The results shows that both proposed controllers perform better than the standard controller when the system is subject to variable external loads, however, the load estimator paired with the gain scheduled PI-controller performs best. / Automatiseringen, inom framförallt tillverkningsindustrin, ökar effektivitet, precision och säkerheten genom att minska den mänskliga faktorn, fel och kassationer. System som utsätts för variabel belastning kan orsaka flera olika problem för automationssystem. En av de största utmaningarna är att bibehålla stabilitet och precision i produktionsprocessen trots förändrade belastningsförhållanden. Dessa variabla belastningar kan leda till instabila system eller fel, vilket ökar felmängden, minskar effektiviteten och sänker produktkvaliteten. Därför är det viktigt att utforma styrsystem som kan anpassa sig till förändrade lastförhållanden och samtidigt upprätthålla stabil och precis drift under oavsett förutsättningar. För att lösa detta problem presenterar denna avhandling en adaptiv regulator baserad på lastidentifiering och gain-scheduling, för att ersätta den vanliga FOC som består av klassiska PI-regulatorer. Lastestimatorn används för att uppskatta den externa lasten med ett relativt litet RMSD, medan gain-scheduling justerar regulatorns förstärkning baserat på den uppskattade belastningen. Andra regulatorer utforskas också, såsom en adaptiv regulator baserad på fel i vinkelhastighet. Resultaten visar att båda föreslagna regulatorer presterar bättre än standardregulatorn när systemet utsätts för variabla externa belastningar, men att lastestimatorn tillsammans med gainscheduled PI-regulatorer presterar bäst.

No description available.

Since their creation, CubeSats have become a valuable educational tool for university science and engineering programs. Unfortunately, while aerospace companies invest resources to develop verification and validation methodologies based on larger-scale aerospace projects, university programs tend to focus resources on spacecraft development. This paper looks at two different types of methodologies in an attempt to improve CubeSat reliability: generating software requirements and utilizing system and software architecture modeling. Both the Consortium Requirements Engineering (CoRE) method for software requirements and the Monterey Phoenix modeling language for architecture modeling were tested for usability in the context of PolySat, Cal Poly's CubeSat research program. In the end, neither CoRE nor Monterey Phoenix provided the desired results for improving PolySat's current development procedures. While a modified version of CoRE discussed in this paper does allow for basic software requirements to be generated, the resulting specification does not provide any more granularity than PolySat's current institutional knowledge. Furthermore, while Monterey Phoenix is a good tool to introduce students to model-based systems engineering (MBSE) concepts, the resulting graphs generated for a PolySat specific project were high-level and did not find any issues previously discovered through trial and error methodologies. While neither method works for PolySat, the aforementioned results do provide benefits for university programs looking to begin developing CubeSats.

<p>Non-destructive characterization of multi-layered structures that can be accessed from only a single side is important for applications such as well-bore integrity inspection. Collimated beam ultrasound systems are a technology for imaging inside multi-layered structures such as geothermal wells. These systems work by using a collimated narrow-band ultrasound transmitter that can penetrate through multiple layers of heterogeneous material. A series of measurements can then be made at multiple transmit frequencies. However, commonly used reconstruction algorithms such as Synthetic Aperture Focusing Technique (SAFT) tend to produce poor quality reconstructions for these systems both because they do not model collimated beam systems and  they do not jointly reconstruct the multiple frequencies.</p> <p><br></p> <p>In this thesis, we first propose a multi-frequency ultrasound model-based iterative reconstruction (UMBIR) algorithm designed for multi-frequency collimated beam ultrasound systems. The combined system targets reflective imaging of heterogeneous, multi-layered structures. For each transmitted frequency band, we introduce a physics-based forward model to accurately account for the propagation of the collimated narrow-band ultrasonic beam through the multi-layered media. We then show how the joint multi-frequency UMBIR reconstruction can be computed by modeling the direct arrival signals, detector noise, and incorporating a spatially varying image prior.</p> <p><br></p> <p>We also propose a ringing artifact reduction method for ultrasound image reconstruction that uses a multi-agent consensus equilibrium (RARE-MACE) framework. Our approach integrates a physics-based forward model that accounts for the propagation of a collimated ultrasonic beam in multi-layered media, a spatially varying image prior, and a denoiser designed to suppress the ringing artifacts that are characteristic of reconstructions from high-fractional bandwidth ultrasound sensor data.</p> <p><br></p> <p>Results using both simulated and experimental data indicate that multi-frequency UMBIR reconstruction yields much higher reconstruction quality than either single frequency UMBIR or SAFT. In addition, our results demonstrate the capability of our RARE-MACE method to suppress ringing artifacts and substantially improve the image quality over single frequency UMBIR and SAFT.</p>

Yes / The process of generating FMEA following document-centric approach is tedious and susceptible to human error. This paper presents preliminary methodology for robotic manufacturing process modelling in MBSE environment with a scope of automating multiple steps of the modelling process using ontology. This is followed by the reasoning towards automatic generation of process FMEA from the MBSE model. The proposed methodology allows to establish robust and self-synchronising links between process-relevant information, reduce the likelihood of human error, and scale down time expenses.

The availability and sophistication of visual display images, such as simulations, for use in science classrooms has increased exponentially however, it can be difficult for teachers to use these images to encourage and engage active student thinking. There is a need to describe flexible discussion strategies that use visual media to engage active thinking. This mixed methods study analyzes teacher behavior in lessons using visual media about the particulate model of matter that were taught by three experienced middle school teachers. Each teacher taught one half of their students with lessons using static overheads and taught the other half with lessons using a projected dynamic simulation. The quantitative analysis of pre-post data found significant gain differences between the two image mode conditions, suggesting that the students who were assigned to the simulation condition learned more than students who were assigned to the overhead condition. Open coding was used to identify a set of eight image-based teaching strategies that teachers were using with visual displays. Fixed codes for this set of image-based discussion strategies were then developed and used to analyze video and transcripts of whole class discussions from 12 lessons. The image-based discussion strategies were refined over time in a set of three in-depth 2x2 comparative case studies of two teachers teaching one lesson topic with two image display modes. The comparative case study data suggest that the simulation mode may have offered greater affordances than the overhead mode for planning and enacting discussions. The 12 discussions were also coded for overall teacher student interaction patterns, such as presentation, IRE, and IRF. When teachers moved during a lesson from using no image to using either image mode, some teachers were observed asking more questions when the image was displayed while others asked many fewer questions. The changes in teacher student interaction patterns suggest that teachers vary on whether they consider the displayed image as a "tool-for-telling" and a "tool-for-asking." The study attempts to provide new descriptions of strategies teachers use to orchestrate image-based discussions designed to promote student engagement and reasoning in lessons with conceptual goals.

Nowadays education becomes a competitive and challenging domain, both na­tionally and internationally in terms of quality, visibility, experience of aca­demic delivery affecting institutions, applicants, regulatory bodies. Currently data becomes more available for the general and public use, and plays also an increasingly significant role in decision support for education topics. For example, world university rankings (WUR) such as Quacquarelli Symonds (QS), Central World University Rankings (CWUR), Times Higher Education (Times) and national university rankings (e.g. the Guardian newspaper Best UK Universities and the Complete University Guide league tables) have published their data for many years now and are increasingly used in such decision making processes by institutions and general public.

Husqvarna Construction is one of the leading construction machinery manufacturers in the world. To stay in the forefront, investing in novel methods to model, test &amp; and optimize machinery is crucial. The most important part of development and testing is to bridge the gap between desired and actual results. Model-based Simulation in testing plays a superior role in visualizing possibilities while cutting down the usage of resources. Floor Grinders are common in industrial and commercial settings to achieve desired floor results. Like every machinery, optimization towards achieving better results is a necessity. The purpose of this thesis is to develop a methodology to optimize Husqvarna Constructions’s floor-grinding machine through its grinding pattern and further study &amp; gather data about the key indicators for an optimum grinding pattern. This is done by setting up a grinding pattern simulation of the PG 690 floor grinder on SIMGRIND (Husqvarna Construction’s own simulation application). A metric was developed to determine whether a grinding pattern is good, and by utilizing the metric as an optimization goal, the impact of different machine parameters on the grinding pattern was established. The grinding &amp; travel speeds were viewed as ratios and it was observed that optimized patterns were attained at particular ratios. Another crucial factor that was studied was the impact of oscillations. Further, the impact of grinding head size on the grinding pattern was also studied. The investigation was limited to a simulation study since physical validation opened up several uncertainties beyond the scope of this work. At the end of this work, a few recommendations for developing physical validation setups are made, to test the results of the simulation.

Mechanical engineers have difficulties when attempting to convey three-dimensional product information in a two-dimensional style. Effective collaboration between various users requires capability to deliver standardized data in a digital format. By digitizing product information and making it available for users apart from designers, Model-Based Definition (MBD) provides a solution by defining to product digitally in a three-dimensional environment. The use of MBD in mechanical design processes can have a positive impact on cost, time, and quality of the final product. Although there are standards for defining digital products, they sometimes do not satisfy specific needs of a variety of product landscapes, necessitating company-specific rules. For a successful deployment of MBD the IT infrastructure must be mature, and a company-tailored guideline document is required to bridge current gaps from standards to corporate needs. Therefore, the aim of this study is to analyse software tools and verify if the IT infrastructure is ready to support transition from drawing-based engineering to model-centric practice. Changes are identified and recommendations will be given. The gained experience from creating models in CAD software along with requirements and feedback from stakeholders and users of the product and manufacturing information is input for creation of the guideline and manual for MBD data practices. This supports the company’s transition to a more efficient product definition. With release of the guideline for applying MBD, the milestone is set to sustainably rely on models instead of drawings for communicating product and manufacturing information. The applied CAD programmes provide all functions transcribing MBD according to applicable standards. The resulting data sets can be interpreted by humans and machines, bringing significant benefits when advancing to model-based enterprise where models are used in all business operations. / Maskiningenjörer och konstruktörer från av olika brancher har svårigheter när de försöker förmedla tredimensionell produktinformation på ett tvådimensionellt sätt. Ett effektivt samarbete mellan olika användare kräver kapacitet att leverera standardiserad data i digitalt format. Genom att digitalisera produktinformation och göra den tillgänglig för andra användningsområden än design ger Model-Based Definition (MBD) en lösning. Användningen av MBD i den mekaniska designprocessen kan ha en positiv inverkan på kostnaden, tiden och kvaliteten på slutprodukten. Även om det finns standarder för att definiera digitala produkter, tillfredsställer de ibland inte de specifika behoven hos en mängd olika produktlandskap, vilket kräver företagsspecifika regler. För en framgångsrik implementering av MBD måste företagets IT-infrastruktur vara mogen, och ett riktlinjedokument krävs för att överbrygga de nuvarande klyftorna från standarderna till företagets behov. Därför analyseras mjukvaruverktygen om dessa är redo att stödja övergången från ritningsbaserad teknik till modellcentrerad praktik. Förändringar identifieras och rekommendationer ges. Erfarenheten från att skapa modeller i CAD-programmen kom tillsammans med input från intressenter och användare av produktdatainmatningen för skapandet av manualen för datapraxis för digital produktdefinition. En nedströmsstudie för interoperabilitet begränsades av en grov programvara tillgänglighet. Med lanseringen av manualen för tillämpning av MBD är milstolpen satt att på ett hållbart sätt förlita sig på modeller istället för ritningar för att kommunicera produkt- och tillverkningsinformation. De tillämpade CAD-programmen tillhandahåller alla funktioner som transkriberar MBD enligt tillämpliga standarder. De resulterande datamängderna kan tolkas av människor och maskiner, vilket ger betydande fördelar när man går vidare till det modellbaserade företaget där modellen används i hela nedströmsströmmen.

The popularity of MPI-based middleware and applications has led to their wide deployment. Such systems, however, are not inherently reliable and cannot tolerate external faults. This thesis presents a novel model-based approach for exploiting application features and other characteristics to categorize and create AEMs (Application Execution Model). This work realizes MPI/FT(tm), a middleware derived by selective incorporation of fault-tolerant features into MPI/Pro(tm) for two relevant AEMs. This thesis proves the following hypothesis: it is possible to successfully complete select MPI applications even in the presence of external faults, and such fault-tolerance can be achieved with acceptable performance overhead. This work defines parameters to measure the impact of this middleware on performance through faultree and fault-injected overheads. The hypothesis is validated through experimentation and measurement of sample MPI applications for two AEMs.