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24 Uppsatser om Robustness - Sida 1 av 2
Reglering av veka strukturer med multipla sensorer
In this master thesis, control algoritms using arm side sensors are investigated for an industrial robot. The sensors can be position encoders placed after the gearbox and accelerometers on the robot arms. Control strategies are discussed and evaluated for different models of the robot, after which chosen strategies are applied to a realistic model. Control algoritms using arm side sensors (LQ, dual-loop and PD-PID) are compared to a PID-controller that only uses measurements of motor position for feedback control. The comparison are done with respect to disturbance rejection, oscillation damping, Robustness and tracking performance of a reference trajectory.
Det kan vara farligt att ligga lågt - om stadsplanering inför stigande vattennivåer : Exempel från Göteborg, Kristianstad och Arvika
In this study is being examined how cities can be planned in the face of rising water levels and extreme weather, due to the changing climate. The starting point has been to investigate how the problems can be tackled and how the positive sides of water in the city can be strengthened, and synergy effects and greater sustainability be achieved thereby. The method has been literature studies and case studies containing interviews and visits. Göteborg, Kristianstad and Arvika have been studied for discussions and ideas about adaptation. Today, building near water is very popular which brings both advantages and disadvantages.
Att optimera samhället inför klimatförändringar : Sårbarhet och anpassning på dagordningen
This thesis examines the ways in which adaptation and vulnerability are framed in national and sectorial policy-documents dealing with expected societal impacts of climate change. By using theories of discourse and ideology, the analysis aims to find and understand important ideas and presuppositions that are explicitly or implicitly expressed in these documents in order to make possible and tangible the institutional production of policy within the potentially far-reaching problematique of climate change adaptation and vulnerability. The analysis shows that there are two main perspectives through which vulnerability and adaptation are framed; one focusing limits to societal Robustness; and one contesting the institutional capacity to implement adaptations. The author understands these framings as complementarily optimizing preconceived social and economic relations, something that might, in fact, reduce the response capacity of people..
Utveckling av modellbaserad reglering i kommersiella styrsystem
In industrial control systems PID-control remains the prevalent strategy, also for processes that would benefit from model based control. The purpose of this thesis is to evaluate whether model based control can be readily implemented in an industrial control system. To this end a simulated surge tank with a simulated industrial control system is studied. For evaluation two scenarios with specified objectives are selected.Following a review of LQR and versions of MPC, Predictive Functional Control (PFC) is considered the most suitable for implementation. PFC is a form of MPC developed with industrial applications in mind and therefore has several advantages for implementation in an industrial control system.
Effekten av Valutarisk på Bilateral Handel
This paper evaluates the effect of exchange rate risk on the sum of bilateral trade. To distinguish the effect between different types of countries, two groups are defined: advanced and developing economies. Economic theory on exchange rate risk and trade proposes ambiguous effects of increased volatility. However, the ex ante hypothesis is that developing economies are more sensitive to volatility. Contrarily to the hypothesis, the empirical results suggest that advanced economies would benefit up to twice as much from a removal of exchange rate risk.
Det elliptiska säkerhetsområdets robusthet : hur robust är metoden med de elliptiska säkerhetsområdena förett symmetriskt men icke normalfördelat datamaterial?
Quality Control is a term often used within production and is referring to managing processes so they produce capable products. Within Quality Control, process capability index is a common measure to oversee processes. Safety Region Plots were introduced to do this graphically. In Albing & Vännman (2010) the concept of Safety Region Plots is expanded to incorporate an elliptical shape. The method of Elliptical Safety Region Plots assumes a normally distributed data.
Undersökning av mätsystem och regulatorstrukturer för industriella tillämpningar
This thesis is divided in to two different parts. The first part includes examination of the measurementsystem of an industrial robot using a resolver sensor. The main focus is on methods for suppressing noise in the angularvelocity signal without increasing timedelay. Five different methods are investigated. Three of these are based on oversampling: burstsamplingmethod, meanvaluemethod and correlationmethod.
Comparison of two methods for evolving recurrent artificial neural networks for
n this dissertation a comparison of two evolutionary methods for evolving ANNs for robot control is made. The methods compared are SANE with enforced sub-population and delta-coding, and marker-based encoding. In an attempt to speed up evolution, marker-based encoding is extended with delta-coding. The task selected for comparison is the hunter-prey task. This task requires the robot controller to posess some form of memory as the prey can move out of sensor range.
DC/DC-omvandlarplattform med DPA-switch för telekomprodukter
In recent years, the penetration of new players on the telecom market hasdrastically increased the work pace, affecting both design and production. Inthis report the technical and economical potential of a DC/DC converterplatform is investigated, in order to shorten the time of the design process.This is done in comparison with the present discrete type designs. PowerIntegrations offers a product, the DPA-Switch?, enabling this.By developing a wide DC/DC converter platform based on the DPA-Switch?,many advantages are gained. The component count is decreased by up to48 % and the yield increases by up to 2.9 % which in all yields a costreduction by up to 43 % or ?390 000 for 100 000 manufactured units.
Validation of realtime-PCR of Fusarium avenaceum for detection in wheat
Mould is a common contamination in cereals. The growth of mould can stimulate mycotoxins production andsome of which at critical concentrations cause health problems in humans and animals. Fusarium is one of thefungus species that has been found in crops and can cause major problems for farmers such as reduced harvestand economic losses. A group of Fusarium species, Fusarium avenaceum, Fusarium poae and Fusariumtricinctum express a mycotoxin, enniatin. The limited information available today about enniatin-forming fungiis that they grow out on fields of wheat in colder climates.
Frekvens och spanningsskalning i en inbyggd mikroprocessor; for att mojliggora implementationen av schemalaggning med stod for dynamisk frekvens- och spanningsreglering for energihantering.
Minimizing power consumption is a critical part of many embedded design projects. Thechallenge is to limit the power consumption of the system and at the same time providesatisfactory service to the user. With regards to microprocessors, the main way of limiting powerconsumption during program execution is to adjust the frequency and the voltage at which theprocessor operates.To enable the implementation of real-time scheduling with support for dynamic voltage andfrequency scaling, an exhaustive study of the Freescale i.MX31 embedded microprocessor isperformed. Specifically, the power consumption relationship to all relevant frequency andvoltage settings is investigated. In addition, to enable frequency and voltage scaling in a real-timeenvironment, a complete timing analysis of proposed voltage and frequency scaling methods isperformed and their suitability for use in real-time systems is evaluated.To integrate voltage and frequency scaling capability into OSE RTOS, a software module hasbeen developed for this operating system.
Gestaltningsförslag till ny förskola på Zakrisdal
Due to increasing regulations regarding new diesel vehicles particulate matteremissions the new Scania truck, Scania Euro 6, has been equipped with a particulatefilter. This component effectively stores the particles in the exhaust gas but must becleaned in order to prevent itself from clogging. The filter is cleaned through aprocess named regeneration which is a thermodynamic process in which thetemperature of the filter is raised through fuel supplied to the exhaust gas.The purpose of this thesis is to contribute to the development of improved controlstrategies of the temperature during the regeneration process through thedevelopment of model-based controllers. These controllers are designed in order tohave good performance in stationary as well as automatic regeneration.In order to develop these model-based controllers a model of the system isconstructed. The model is described as a linear thermodynamic grey-box model withflow varying parameters, showing good results in validation.The model provides a simulation environment during the controller design, which isfocused around the development of linear regulators with the exhaust gas mass flowas a scheduling variable whose size determines controllers? mode of operation.
Ekonomiskt bist?nd och brottslighet i Sverige
This study examines the connection between Sweden`s crime rate and financial aid, focusing on the effects of social spending on different types of criminal activity in the Swedish municipalities between 2000 and 2022. Using theories such as social support theory and utility maximization, the study investigates the relationship between economic assistance and crimes like theft, attempted murder, drug offenses, and assault. The results suggest a complicated relationship: financial aid is associated with a rise in drug offenses and assaults but a decrease in larceny and robberies, when controlling for all observed and unobserved time invariant factors in the municipal factors (a fixed effects panel data model). However, when we test our model for Robustness, the effects disappear meaning that other factors that are time varying in the municipality are biasing our estimates. Examples for this may be factors like peer pressure, substance addiction, and socioeconomic conditions that have a considerable impact on criminal conduct, financial aid alone may not be adequate to curb crime.
Profitability of Momentum Strategies on the Nordic stock market
Purpose: The main purpose of the thesis is to examine the profitability of Momentum Strategies on the Nordic stock markets. This will provide insight and contribute to the debate on efficient markets. Finding profitable Momentum Strategies will provide strong evidence of inefficiency in the market. A secondary purpose is to examine factors which might cause or impact the profitability of the Momentum Strategy. We will look closely at the relationship between the profitability and factors such as risk (CAPM-beta), market capitalization, trading volume and seasonality.
Konstruktion och prototypframtagning av pallväxlare
This thesis was conducted at AB Fredr Wagner in Ösmo in Nynäshamn, Sweden.AB Fredr Wagner provides solutions for the graphic industry and has been asked by acustomer to develop a product that can simplify handling of EUR-pallets, namely amechanical arrangement, further called pallet exchanger that can switch from anempty pallet to a fully loaded one using only hand force.The goal with the thesis was to create design documents for a pallet exchanger, andalso from those documents to manufacture a prototype for testing and evaluation.A field trip was made to the customer, IKAB mailing in Huddinge, where the palletexchanger is thought to be placed. The purpose of this field trip was to get an insightinto the current work condition and need of change, as well as to gather informationregarding the requirements when it comes to size and Robustness of the palletexchanger. Existing equipment on the market that can perform similar tasks werestudied in order to find an optimal solution for the actual pallet exchanger.After the field trip and gathering of information the concept generating phase began.The method used for generating concepts was brainstorming. To decide on whichconcept to use, a concept selection matrix was created. The selection criteriaincluded in the matrix came from the requirements for the pallet exchanger.