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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
221

Optimal control of a diesel engine with EGR and VGT

Welander, Markus, Olsson, Jonas January 2006 (has links)
<p>To fulfill todays requirements on emissions from engines, SCANIA has developed an engine with EGR (Exhaust Gas Recirculation) and VGT (Variable Geometry Turbine). This gives two extra control signals to take into consideration. Open loop optimal control is used to investigate how these two actuators should be controlled to minimize emissions and fuel consumption. A cost function, consisting of the errors between the most important variables and their set points, has been used in the minimization. The variables are the torque, the EGR mass fraction, the oxygen/fuel ratio and the pumping losses.</p><p>From studies of the two control signals in different transients in the engine, information of how to control the VGT and EGR in the optimal way is found. The result from the optimal control has been compared with a PID simulation and has showed a better way to control the signals. The mayor reason why the optimal control is better than a PID controller is the ability to use future values from the transients.</p>
222

Fleet Management Services in GSM-modules

Hellström, Nils January 2007 (has links)
<p>This report studies a low cost hardware platform for Fleet Management Services, FMS. The platform manages vehicle data, positioning and wireless communication. The core of the platform is a new kind of ‘intelligent’ GSM modem, called a GSM module. A GSM module is basically a stripped down mobile phone that allows embedded third party application code and has an IP-stack. The report reviews the modules available on the market today and presents experiences from the implementation of a prototype based on the Aplicom A12 module. The main conclusion is that the concept is feasible though the modules' limited performance must be considered in the design.</p>
223

Combining the Good Things from Vehicle Networks and High-Performance Networks

Armide, Misikir, Ecker, Herbert January 2007 (has links)
<p>The aim of this Master’s thesis is to develop a solution for combining speed and performance of switched Ethernet with the real time capability and determinism of sophisticated in- vehicle networks. After thorough research in vehicle network standards, their demands and features, the</p><p>Flexible Time Division Multiple Access (FTDMA) protocol of FlexRay was chosen to be applied on a switched Ethernet architecture since it can accommodate both hard real time tasks and soft real time tasks. To provide hard real time capability, what this paper focuses on, a media access method was developed by creating static TDMA schedules for each node’s sending and receiving</p><p>port according to a certain traffic assumption. To validate the developed media access algorithm several examples with different traffic assumptions and architectures were generated and</p><p>investigated based on their sending and receiving utilization. A second method for validating and thus proving the functionality of the algorithm was by simulation. Therefore the Matlab Simulink</p><p>media library extension TRUE TIME was used to simulate a simple example with 100% sending and receiving utilization for each node.</p>
224

Motorsimulering av CAN-buss : Boxcar 9-5

Richardson, Malin, Sandell, Unn January 2003 (has links)
No description available.
225

CAN bus diagnostic tool for PocketPC

Pettersson, Marcus January 2002 (has links)
No description available.
226

Utveckling av en provmetod för ett CAN-baserat nätverk

Skopo, Aldijana, Börnstedt, Mattias January 2004 (has links)
No description available.
227

Informationen flödar : - men vem förmedlar?

Fihn, John, von Koch, Carl January 2009 (has links)
<p>Syfte: Syftet med vår studie är att undersöka hur information kan hanteras med ett integrerat affärssystem till stöd för controllers och personer med ledande befattningar.</p><p>Metod: Vi genomförde en fallstudie där vi intervjuade controllers och personer med ledande befattningar på WSP. Detta för att kartlägga de informationsbehov som finns utifrån deras centrala arbetsuppgifter. Med utgångspunkt från en teoretisk referensram och med vetskap om deras informationsbehov analyserade vi hur information kan hanteras med hjälp av ett integrerat affärssystem till stöd för dem.</p><p>Resultat: För personer med ledande befattningar handlar det ofta om att få information för att ta sig till beslut, och de behöver oftast olika sorters information. Controllern har en central roll för att hantera och vidarebefordra information, och det är viktigt att det finns bra verktyg för att hantera och distribuera information. Ett integrerat affärssystem kan vara till stöd för hantering och spridning av information, och vid utformandet av affärssystemet är det viktigt att skapa en presentation av informationen som stimulerar användaren och ger möjlighet för användaren att förstå dess innehåll. Informationen kan få ett högre eller lägre värde beroende på huruvida informationen presenteras ihop med annan information eller inte. Det är viktigt att uppmärksamma väsentlig information och automatisera informationshantering så att controllers och chefer kan bli mer organiserade i sitt arbete och spara tid.</p>
228

Iterative model-free controller tuning

Solari, Gabriel 08 August 2005 (has links)
Despite the vast amount of delivered theoretical results, regarding the topic of controller design, more than 90% of the controllers used in industry (petro-chemical, pulp and paper, steel, mining, etc) are of PID type (P, PI, PII, PD). This shows the importance of progressing in the elaboration of methods that consider restricted complexity controllers for practical applications, and that are computationally simple. Iterative Feedback Tuning (IFT) stands out as a new solution that takes into account both constraints. It belongs to the family of model-free controller tuning methods. It was developed at Cesame in the nineties and, since then, many real applications of IFT have been reported. This algorithm minimizes a cost function by means of a stochastic gradient descent scheme. In spite of the fact that the method has had an unexpected success in the tuning of real processes, a number of issues had not been fully covered yet. This thesis focuses on two aspects of this set of uncovered theoretical points: the convergence rate of the algorithm and a robust estimation of its gradient. Optimal prefilters, left as a degree of freedom for the user in the first formulation of IFT, are computed at each experiment. Their application allows a reduction in the covariance of the gradient estimate. Depending on what particular aspect the user is interested in improving, one optimal prefilter is selected. Monte-Carlo simulations have shown an enhancement with regards to a constant prefilter. A flexible arm set-up mounted in our robotics laboratory is used as a test bed to compare a model-based controller design algorithm with a model-free controller tuning method. The comparison is performed with some specifications defined beforehand. The same set-up plus a couple of air-jets serves as a tester for our theoretical results, when the rejection of a perturbation is the ultimate objective. Both cases have confirmed the predicted good behaviour offered by IFT.
229

System modeling and controller designs for a Peltier-based thermal device in microfluidic application

Jiang, Jingbo 06 1900 (has links)
A custom-made Peltier-based thermal device is designed to perform miniaturized bio-molecular reactions in a microfluidic platform for medical diagnostic tests, especially the polymerase chain reaction for DNA amplification. The cascaded two-stage device is first approximated by multiple local linear models whose parameters are obtained by system identification. A decentralized switching controller is proposed, where two internal model-based PI controllers are used in local stabilizations and PD and PI controllers are applied during transitions respectively. Couplings and drift are further reflected into the controllers. Desired temperature tracking performance on the transition speed and overshoot is achieved, and the feasibility of the Peltier device in a microfluidic platform is further validated by the successful applications of viral detection. To achieve fast and smooth transition while avoiding tuning by trial-and-errors, a nonlinear model is developed based on the first principles, whose parameters are partially calculated from empirical rules and partially determined by open-loop and closed-loop experimental data. Two novel nonlinear controllers are designed based on the nonlinear model. The first controller extends the input-to-state feedback linearization technique to a class of nonlinear systems that is affine on both the control inputs and the square of control inputs (including the Peltier system). Additional local high gain controllers are introduced to reduce the steady-state errors due to parameter uncertainty. The second controller is a time-based switching controller which switches between nonlinear pseudo-PID/ state feedback controllers and local PI controllers. Calculation burden is reduced and steady-state error is minimized using a PI controller locally, while fast and smooth transition is achieved by the nonlinear counterpart. The robustness of the controller is verified in simulation under worse case scenarios. Both simulation and experimental results validated the effectiveness of the two nonlinear controllers. The proposed linear/ nonlinear, switching/ non-switching controllers provide different options for the Peltier-based thermal applications. The scalability and the parameter updating capability of the nonlinear controllers facilitate the extension of the Peltier device to other microfluidic applications. / Controls
230

Organisational structure influences on the controller roles in Sweden : A cross case study between six organisations in the clothing industry

Kristofersson, Ann, Falk, Johanna, Jonson, Christofer January 2008 (has links)
Background: Increasing competition has led to a large interest for management control and leadership in Sweden. The controller’s role has changed from just including number crunching tasks to become more market and customer oriented. Therefore the use of controllers today is increasing within Swedish organisations. The role incorporates involvement in management decision making process. Organisational structure affects the work role as well as the location of the employee within an organisation. Purpose: Our objective is to explore how and why the controller roles in Sweden differ from one organisation to another. To make it more interesting a second dimension, organisational structure, is included. We aim to develop guidelines that can provide useful insights to already existing theory. A mix between the inductive and the deductive approach is used. Method: A qualitative cross case study has been performed where controllers from six different organisations present in the Swedish market have been interviewed. The organisations are operating in the clothing industry. Generalisation is not emphasised rather the uniqueness of each case is highlighted. A cross case analysis was performed to reveal differences and similarities between the cases. Conclusion: We have found that a divisionalised structure where the subsidiary is relatively large results in decentralised decision making. The controller belongs to an own function located straight below the CEO and is titled business controller. This controller is recognised to be an involved controller. The involved controller was also found in organisations where some influences of the machine bureaucracy were apparent. If the controller belongs to the finance function it is likely that he/she performs accounting related tasks and the controller role is recognised to be the independent controller. If the controller belongs to the purchase function and the adhocracy is found the split controller role is evident. To prevent confusion we suggest that more controller titles should be added and the title should also communicate what tasks and responsibilities that correspond to the role. If you belong to the finance function an appropriate title would be accounting controller. By looking at the organisational structure it is possible to get guidance for what the role incorporates and what tasks and responsibilities that can be expected. Variance will always apply since there are no rules and regulations for financial control.

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