Legislators steadily increase the demands on lowered emissions from heavy duty vehicles. To meet these demands it is necessary to integrate technologies like Exhaust Gas Recirculation (EGR) and Variable Geometry Turbochargers (VGT) together with advanced control systems. Control structures are proposed and investigated for coordinated control of EGR valve and VGT position in heavy duty diesel engines. Main control goals are to fulfill the legislated emission levels, to reduce the fuel consumption, and to fulfill safe operation of the turbocharger. These goals are achieved through regulation of normalized oxygen/fuel ratio and intake manifold EGR-fraction. These are chosen as main performance variables since they are strongly coupled to the emissions. To design successful control structures, a mean value model of a diesel engine is developed and validated. The intended applications of the model are system analysis, simulation, and development of model-based control systems. Dynamic validations show that the proposed model captures the essential system properties, i.e. non-minimum phase behaviors and sign reversals. A first control structure consisting of PID controllers and min/max-selectors is developed based on a system analysis of the model. A key characteristic behind this structure is that oxygen/fuel ratio is controlled by the EGR-valve and EGR-fraction by the VGT-position, in order to handle a sign reversal in the system from VGT to oxygen/fuel ratio. This structure also minimizes the pumping work by opening the EGR-valve and the VGT as much as possible while achieving the control objectives for oxygen/fuel ratio and EGR-fraction. For efficient calibration an automatic controller tuning method is developed. The controller objectives are captured by a cost function, that is evaluated utilizing a method choosing representative transients. Experiments in an engine test cell show that the controller achieves all the control objectives and that the current production controller has at least 26% higher pumping losses compared to the proposed controller. In a second control structure, a non-linear compensator is used in an inner loop for handling non-linear effects. This compensator is a non-linear state dependent input transformation. PID controllers and selectors are used in an outer loop similar to the first control structure. Experimental validations of the second control structure show that it handles nonlinear effects, and that it reduces EGR-errors but increases the pumping losses compared to the first control structure. Substantial experimental evaluations in engine test cells show that both these structures are good controller candidates. In conclusion, validated modeling, system analysis, tuning methodology, experimental evaluation of transient response, and complete ETC-cycles give a firm foundation for deployment of these controllers in the important area of coordinated EGR and VGT control.

System identification is about constructing and validating modelsfrom measured data. When designing system identificationexperiments in control applications, there are many aspects toconsider. One important aspect is the choice of model structure.Another crucial issue is the design of input signals. Once a modelof the system has been estimated, it is essential to validate theclosed loop performance if the feedback controller is based onthis model. In this thesis we consider the prediction-erroridentification method. We study model structure complexity issues,input design and model validation for control. To describe real-life systems with high accuracy, models of veryhigh complexity are typically needed. However, the variance of themodel estimate usually increases with the model order. In thisthesis we investigate why system identification, despite thisrather pessimistic observation, is successfully applied in theindustrial practise as a reliable modelling tool. It is shown thatby designing suitable input signals for the identificationexperiment, we obtain accurate estimates of the frequency functionalso for very complex systems. The input power spectrum can beused to shape the model quality. A key tool in input design is tointroduce a linear parametrization of the spectrum. With thisparametrization, several optimal input design problems can berewritten as convex optimization problems. Another problem considered is to design controllers withguaranteed robust stability and prescribed robust performanceusing models identified from experimental data. These models areuncertain due to process noise, measurement noise and unmodelleddynamics. In this thesis we only consider errors due tomeasurement noise. The model uncertainty is represented byellipsoidal confidence regions in the model parameter space. Wedevelop tools to cope with these ellipsoids for scalar andmultivariable models. These tools are used for designing robustcontrollers, for validating the closed loop performance and forimproving the model with input design. Therefore this thesis ispart of the research effort to connect prediction-erroridentification methods and robust control theory. The stability of the closed loop system can be validated using thesmall gain theorem. A critical issue is thus to have an accurateestimate of the L2-gain of the system. The key tosolve this problem is to find the input signal that maximizes thegain. One approach is to use a model of the system to design theinput signal. An alternative approach is to let the system itselfdetermine a suitable input sequence in repeated experiments. Insuch an approach no model of the system is required. Proceduresfor gain estimation of linear and nonlinear systems are discussedand compared. / QC 20100702

To deliver a reliable communication service over the Internet it is essential for the network operator to manage the traffic situation in the network. The traffic situation is controlled by the routing function which determines what path traffic follows from source to destination.  Current practices for setting routing parameters in IP networks are designed to be simple to manage. This can lead to congestion in parts of the network while other parts of the network are far from fully utilized. In this thesis we explore issues related to optimization of the routing function to balance load in the network and efficiently deliver a reliable communication service to the users. The optimization takes into account not only the traffic situation under normal operational conditions, but also traffic situations that appear under a wide variety of circumstances deviating from the nominal case. In order to balance load in the network knowledge of the traffic situations is needed. Consequently, in this thesis we investigate methods for efficient derivation of the traffic situation. The derivation is based on estimation of traffic demands from link load measurements. The advantage of using link load measurements is that they are easily obtained and consist  of a limited amount of data that need to be processed. We evaluate and demonstrate how estimation based on link counts gives the operator a fast and accurate description of the traffic demands. For the evaluation we have access to a unique data set of complete traffic demands from an operational IP backbone.  However, to honor service level agreements at all times the variability of the traffic needs to be accounted for in the load balancing. In addition, optimization techniques are often sensitive to errors and variations in input data. Hence, when an optimized routing setting is subjected to real traffic demands in the network, performance often deviate from what can be anticipated from the optimization. Thus, we identify and model different traffic uncertainties and describe how the routing setting can be optimized, not only for a nominal case, but for a wide range of different traffic situations that might appear in the network.  Our results can be applied in MPLS enabled networks as well as in networks using link state routing protocols such as the widely used OSPF and IS-IS protocols. Only minor changes may be needed in current networks to implement our algorithms. The contributions of this thesis is that we: demonstrate that it is possible to estimate the traffic matrix with acceptable precision, and we develop methods and models for common traffic uncertainties to account for these uncertainties in the optimization of the routing configuration. In addition, we identify important properties in the structure of the traffic to successfully balance uncertain and varying traffic demands. / QC 20110211

Today small metal parts are mass-produced as for example rollers in cylinder bearings. At high velocity cutting the metal is cut with a great force in a scissor-like device. Both precision and repeatability is important to be able to guarantee good quality, but from an economical point of view it is also important to keep a great manufacturing capacity. The part of the process that is most time consuming is when the metal bar, that is about to be cut, is fed to the right position. Therefore it is interesting to examine if the time used for positioning can be reduced. This thesis examines if more advanced automatic control can be used to speed up the process while maintaining the precision. In order to test and evaluate different theories, two different mathematical models have been developed. The models where implemented in the simulation program SIMULINK in MATLAB and they where compared to and adapted to data measured on the physical machine. One model is developed from physical relationships and mostly used for simulations while the other one, a condition state model, has been used for regulator design. The first question to answer was if it is at all possible to control the process any faster. When a theoretical limit was found the next step was to design a regulator to show that the theory of automatic control does not imply too great limitations. The design that was chosen was condition state feedback where the states were appraised with an observer. A faster system will raise the demands on cycle times and precision. To make sure that the hardware isn’t the limiting factor, design requirements have been set up. A small list of what hardware is available has also been put together (and shows that it is possible to implement such a system). The conclusion is that it is, theoretically, possible to radically increase the manufacturing capacity. The assumptions for this to be accomplished is especially that the uncertainty of the model is minimizedand that hardware with enough capacity can be found.

The aim of the thesis is to develop and describe WRAP’s capabilities in handling the WiMAX standard as defined in IEEE 802.16e related to traffic capacity calculations. WRAP International has developed the software WRAP for spectrum management and radio network planning. WRAP includes various technical calculation functions that are applied for design and analysis tasks with the purpose of achieving the desired quality of service within radio communication networks, navigation and radar systems. WRAP already includes functions for radio wave calculations to establish for instance coverage; best server maps etc, as well as traffic calculations for cellular networks (2G) using channel-orientated calculations that are modeled by Erlang B and Erlang C formulas. Since WiMAX supports multiple broadband data services including voice, video, web data, interactive network gaming and streaming media so there is a need to build a tool for the estimation of WiMAX traffic capacity calculations. Some methods and algorithms are analyzed and a tool has been built to ease the network planner’s job. It works based upon the calculations and algorithm presented in the report. Total number of users and data rate supported by a base station is calculated and total number of base stations, required for the coverage of a specific area is determined. This new tool is compatible with WRAP’s current functions.

Från Sjövärnskåren division syd, underavdelning Blekinge, inkom en förfrågan om att göra en undersökning och projektering till ett digitalt maskinövervakningssystem. Syftet med maskinövervakningssystemet är att det ska vara lättare för de som tränas ombord att ta till sig maskineriets kondition. Detta kommer att bidra till att minska underhållskostnaderna genom att förbättra övervakningen under drift, för att undvika oönskade driftfall, och dels att förbättra driftsdokumentationen som underlag för beslut om underhållsåtgärder/-intervaller. Projektet innebar en föreberedande undersökning av vilken utrustning som behövs till det nya systemet samt för att få en kostnadsram åt Sjövärnskåren. Vi träffades i Karlskrona för att komma överens om vilka maskinparametrar som skulle presenteras. Därefter påbörjades förundersökning och dokumentationsgenomgång för att ta reda på vilka givare det var samt vad för signal de gav till det befintliga övervakningssystemet. Detta visade sig bli en stor del av projektet som tog mycket tid. Vi var och mätte signalerna från givarna på fartyget utan att komma fram till slutsats. Efter att ha pratat med varv och underhållsenheter som fartyget varit i kontakt med under sin tid i försvaret, hittade vi en källa som var mycket kunnig i området. Denne uppgav muntligen information som innebar att givarna skulle ge standardsignal, 4-20 mA. Projektet fortskred med denna information och offertunderlag gjordes och skickades ut till olika företag som hade produkter som kunde klara av uppgiften. Det inkom tre system som skulle klara av uppgiften. Alla dessa innebär omfattande programmeringsarbete för att få controllern att hantera och presentera informationen som det är tänkt. Samtliga system programmeras med funktionsblock (FB) eller strukturerad text, (ST). Även för den insatte i dessa språk kommer det att bli en ansenlig mängd programmeringstimmar. / This exam work was initiated by a request from Sjövärnskåren division Syd. They wanted to implement a newer, computer based system with graphical display, an engine monitoring system which was ment to provide the engineer on watch with data from the engines. The object for this is to reduce the maintenance costs through improved monitoring while running and to improve documentation which later on the maintenance measures is based on. The project was an initial study which conclusions and recommendations on systems suited for the task is to give Sjövärnskåren an economical frame. We met up in Karlskrona on the ship and had a discussion about which parameters that should be presented. After that we started to go through the documentation and perform onsite surveys to conclude what signals the transmitters put out to the existing monitoring system. This was a delicate task, information about the transmitters was lacking in the documentation. The onsite measures gave no vital information. We talked to the shipyards and maintenance units that the ship had been in contact with during its time in the navy. We came in contact with a man that had been working with this ship, and he gave us information that told us that the transmitters were of standard type, 4-20 mA. With this information, the project pursued and we invited tenders to give us systems that could cope with the task. We had three tenders thar supplied us with systems. All of theese meant considerable programmingwork to get the monitoring system up and running.

No description available.

Modern missiles must meet higher and higher demands. They should be autonomous, have long range and still have a big effect on the target. To maximize effect on target some missiles not only minimize miss distance, but also try to hit with a certain angle; often perpendicular to the surface of the target. In this thesis a method to guide the missile in the terminal phase of its mission where both point of impact as angle of impact are specified. The method consist of two parts. First a reference trajectory with best possible impact conditions, considering the performance of the missile, is computed. The second part consist of a guidance law which guide the missile along the reference trajectory to the target. Two laws were tested, Biased Proportional Navigation (BPN) and Modified Biased Proportional Navigation (MBPN). The method was implemented in an existing detailed simulation system. A big number of simulations were done to optimize the algorithms, and to evaluate performance. Performance was then compared to an already existing method for terminal guidance. The new method was better in terms of angle of impact but worse considering point of impact. One big advantage with the new method is that after calculation of the reference trajectory but before the actual flight (to target) it is possible to predict, with a high level of certainty, if the missile is going to hit the target or not.

På moderna missiler ställs inte bara krav på nedslagsposition utan i allt högre grad även på nedslagsvinkel. För hårt bepansrade mål är vinkeln kritisk då det finns risk att missilen studsar om den kommer in allt för flackt. Samtidigt ökar träffprestandan då en optimal nedslagsvinkel och nedslagsposition används. Med anledning av detta föreslås en styrlag för att reglera missilen efter på förhand genererade referensbanor i vilka nedslagsposition och nedslagsvinkel kan specifieras. Styrlagen är indelad i två huvuddelar och inleds med en optimal styrlag för att reglera ut navigationsfel från tidigare faser och ta missilen till referensbanan. Därefter tar en banföljningsalgoritm vid för att följa referensbanan, vilken konstruerats som interpolerade referenspunkter. Styrlagen har implementerats i en befintlig simulator bestående av en missilmodell och en omvärldsmiljö. I denna simulator har prestanda för styrlagen jämförts för ett flertal olika fall med en befintlig styrlag. Simuleringsresultaten visar att en mycket god positions- och vinkelnogrannhet erhålls vid navigationsfel upp till en viss gräns. Därefter räcker inte den tillgängliga accelerationen till, med positionsfel som följd.

<p>This master's thesis presents the development of a collision handling function for Motoman industrial robots and investigates further use of the developed software. When a collision occurs the arm is to be retracted to a safe home location and the job is to be restarted to resume the production. The retraction can be done manually, which demands that the operator has to have good knowledge in robot handling and it might be a time consuming task. To minimise the time for restarting the job after a collision and allowing employees that have limited knowledge in robot handling to retract and restart the job, Motoman provides an automatical retraction function. However, the retraction function may cause further collisions when used and therefor a new function for retracting the arm is needed. The new function is based on that the motion of the robot is recorded by sampling the servo values, which are then stored in a buffer. A job file is automatically created and loaded into the control system, and the position variables of the job file are updated using the contents of the buffer. This will ensure a safe retraction of the arm as long as the environment surrounding the robot remains the same.</p><p>The developed software made it possible to control the robot in real-time by changing the buffer information, which has lead to a cognitive system called the Pathfinder. By initiating the Pathfinder function with at least a start and an end point, the function generates a collision free path between the start point and the end point. A pilot-study has also been made concerning integration of a vision system with the Pathfinder to increase the decision handling for the function.</p>