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In this paper we propose a hybrid approach for solving vehicle routing problems. The main idea is to combine an Ant System (AS) with a problem specific constructive heuristic, namely the well known Savings algorithm. This differs from previous approaches, where the subordinate heuristic was the Nearest Neighbor algorithm initially proposed for the TSP. We compare our approach with some other classic, powerful meta-heuristics and show that our results are competitive. / Series: Report Series SFB "Adaptive Information Systems and Modelling in Economics and Management Science"

This thesis is concerned with the synthesis of linear-optimal heave control of electromagnetic suspension systems. The methods of computer-aided analysis and simulation were employed in this research. The intrinsic properties of electromagnetic suspension system were investigated to facilitate the synthesis and to provide guidelines for the design of electromagnets or linear motors suitable for use in suspension systems. The technique of complementary filtering, which resolves the conflicting requirements of high stiffness to load and high compliance for ride-comfort, was further developed. This led to the ability of directly comparing the merits of systems with different configurations and determining the optimal natural frequency. Together with a novel way of removing steady state gap error during the traversing of transition curves, the filtering technique was applied to the system using fixed-gain and sliding-mode variable-structure control methods. The latter method is well known for its abi1ity in maintaining closed-loop characteristics in the presence of disturbance. However, further development was required before it was applied. The resultant suspension system gave a 20% improvement in ride-quality over the best published result which was carried out under similar test conditions. Even so, theoretical analysis showed that a four-fold improvement may be possible.

Le monde des Véhicules à Deux Roues Motorisés (VDRM) a changé considérablement,en matière de qualité et de performances. Ces véhicules ont pris une place importante dans notre vie quotidienne, que ce soit pour les déplacements ou les loisirs, ce qui a contribué à l’augmentation et à la diversité du parc. Néanmoins, la sécurité des usagers est devenue une des préoccupations des institutions routières et des organismes de recherche, vu le nombre croissant des accidents et la vulnérabilité à laquelle sont confrontés. Nos travaux de recherche s’inscrivent dans la thématique d’étude (modélisation et observation) et d’analyse de la dynamique limite des VDRM. L’objectif étant la conception des outils nécessaires à l’établissement de systèmes d’aide à la conduite, de type préventif, dédiés à renforcer la sécurité du conducteur et à améliorer sa conduite. Le principal outil est un bon dispositif de simulation, vu les contraintesrencontrées pour la réalisation en pratique des tests, tel que la sécurité du pilote, le coût, etc. C’est ainsi, qu’une synthèse de trois modèles dynamiques non linéaires, àun corps, à deux corps et à cinq corps, est proposée. Une fonction de risque, relativeà l’angle de roulis du véhicule maximal, est établie. Sa variation en fonction desparamètres inertiels et géométriques de l’ensemble véhicule et conducteur, de leursdynamiques et de l’infrastructure, a fait l’objet d’une étude approfondie. La difficultéd’implémentation de nombreux capteurs, nous a conduit à concevoir des méthodesd’observation des dynamiques importantes pour la mise en pratique des systèmesde sécurité. Pour ce faire, nous avons reconstruit les grandeurs, contribuant à la dynamique latérale, par l’application de l’observateur Proportionnel Double Intégral(P2I) sur deux cas de modèles (3DDL et 4 DDL). La dernière partie du mémoire, est consacrée aux travaux réalisés sur l’instrumentation du prototype Scooter dont dispose le laboratoire. L’analyse des données enregistrées sur piste et la validation des techniques d’observation développées y sont détaillées. / The world of Powered Two Wheeled (PTW) vehicles has changed considerably in quality and performance. These vehicles have taken an important place in our live, whether for transportation or leisure, which contributed to the increasing and diversity of their park. However, the safety of users has become a concern of road institutions and research organizations, given the increasing number of accidents and vulnerability at which they are faced. Our research fall within the thematic study of modeling, observation and dynamic limit analysis of the PTW vehicles. The main objective is to design tools needed to establish safety systems, of preventive kind, dedicated to enhance driver safety and improve his conduct. The main tool is a good device simulation, given the constraints encountered in the practical realization of tests, such as driver safety, cost, etc. For this, a synthesis of three non-linear dynamic models of one body, two bodies and five bodies, is proposed. A risk function relative to the maximum roll angle of the vehicle is established. Its variation according to the inertial and geometric parameters of the whole vehicle and driver, their dynamics and infrastructure, has been subject of extensive study. The difficulty of implementing many sensors has led us to develop methods to reconstruct the important dynamics for the implementation of safety systems. To do this, we reconstructed quantities contributing to the lateral dynamics by applying the Proportional Two Integral (P2I) observer. The last part of the manuscript is devoted to the work carried out about the instrumentationof the Scooter prototype, available at our laboratory. The analysis of the recorded data on the test track and the validation of the observers developed are detailed.

<p>Den här rapporten ämnar svara på frågan om och med hur mycket tröskelvärdena av alla inkommande komponenter, tillhörande ett MD-80 Engine change kit, kan höjas med och vilka kostnadsbesparingar en sådan höjning kan medföra. Undersökningen har föranletts av företaget SAS Components vilja att få reda på om en optimering av tröskelvärden kan leda till en minskning av kasserade komponenter hos dem.</p> / <p>This report’s aim is to verify if it is possible, and if so, by how much SAS Component could increase the threshold values of all incoming components belonging to an MD-80 Engine Change Kit. How would this raise in the components threshold lower SAS Component’s expenses?</p>

<p>Sammanfattning</p><p>Dagens stigande bränslepriser gör det alltmer viktigt för tillverkare samt brukare av fordon, att fokusera på detaljer som kan minimera drivmedelåtgången. Scania linjetrafikbussar är utrustade med ett antal olika konfigurationer av kåpor som figurerar på bussarnas tak.</p><p>Projektet har således innefattat att undersöka dessa ur ett aerodynamisk perspektiv i Mälardalens högskolas låghastighetsvindtunnel, förlagt vid Hässlö i Västerås.</p><p>Resultaten som uppnåddes är att motståndskofficienten kan reduceras från CD=0,46 till CD=0,41 genom att omplacera orginalkåporna på andra positioner över taket. CD =0,39 erhålls genom att bruka de aerodynamiskt modifierade kåporna. Det skapar en vinst på 55-60 000 kr för orginalkåporna och motsvarande en vinst på 75-80 000 kr för de modifierade kåporna, räknat under bussens livslängd och en drivmedelkostnad på 8 kr/l. Beräkningarna är snålt tilltagna för att ej ge ett överskattat värde, utan är mer ett resultat i underkant. I bilagorna figurerar även andra värden som ger än mer större vinst i kronor</p><p>Resultat uppnås då man tenderar minimera det återcirkulerande och energialstrande flöde som skapas inledningsvis på bussens tak under dess färd.</p>

<p>This thesis work was executed at Swift Engineering Incorporated located in San Clemente, California during spring in 2009. Placement supervisor from Swift was Mark Page and advisor and examiner from the Division of future products at Mälardalen University, Sweden was Gustaf Enebog.</p><p>The objective with this thesis work was to examine the effects of fitness ratio, lift over drag, lift coefficient at cruise, winglet span, wing sweep angle, wing aspect ratio, wing area and weights with respect to Mach number for a conventional business jet capable of 18 passengers. The cruise speed study range from Mach 0.88 to 0.99.</p><p>The Excel based conceptual design tool Jetsizer 2008c was used to make four models with similar configuration and mission but with different cruise Mach numbers.</p><p>A new Jetsizer module was then created to handle a modification process where the models are optimized for their speed and configuration. The result in this report gives guidelines for the needed values when creating an initial CFD model for this type of airplane.</p>

<p>In recent years, the number of vehicles has increased dramatically in Europe, USA and Japan. This causes a high traffic density and makes new security features a crucial point in order to keep the traffic safe. Inter-vehicle communication offers solutions in this field, as cars can communicate with each other. To this date, there is no special technology standardized for inter-vehicle communication. This is the reason why car makers, researchers and academics have invested money and time in different research projects so that in future they may come up with a common solution. Some of the technologies like DSRC, CALM, IEEE 802.11 or Infrared are thought to be more reliable than others according to different authors [9][23].</p><p>The technologies described above will help to improve road safety and application scenarios like lane change, blind merge or pre and post crash situations can be addressed. The position of each car is known through a GPS; speed, heading and other dynamic data of a car are known to all cars in the same vicinity.</p><p>In this thesis, a thorough investigation of services and applications related to inter-vehicular communication technology (i.e. car-to-car and car-to-infrastructure or vice versa) will be carry out. The emphasis will be on requirements on the communication system, sensors and user interface in order to make the technology more useful for future vehicle alert system and to avoid as many of the mentioned scenarios as possible. A rear-end collision can be avoided if the driver is warned within 0 to 5 second of potential accident.</p>

In this thesis, optimization is used to improve the performance of aircraft. The focus is on operating current generation aircraft more efficiently rather than designing new aircraft. Drag minimization and aircraft trajectory optimization is used to increase efficiency. Optimization methods are implemented and evaluated on different problem formulations. The first part of the thesis presents a drag minimization strategy using multiple control surfaces distributed across the span of an elastic wing. Aeroelasticity is exploited to reduce drag for a wide range of flight conditions. A method to minimize drag during a long distance flight is developed and tested in a wind tunnel environment. The method is based on continuously changing the control surface deflections to obtain a more beneficial load distribution from a drag point of view for the current flight condition. In a second study, the method is extended to include the angle of attack as a variable together with the control surface deflections in the drag minimization algorithm. Extensive wind tunnel testing demonstrates the possibility to reduce drag significantly with the presented method for a wide range of flight conditions. The second topic in the thesis is optimizing the aircraft trajectory. The emissions from the aircraft engine are modeled as smooth functions suitable for optimization using published certification data. These emissions are combined in different environmental indices and used as objective functions in the aircraft trajectory optimization problem. The optimization problem is formulated by discretizing the trajectory in time. The resulting large scale nonlinear optimization problem is solved using a sequential quadratic programming method. The trajectory optimization problem is first studied using a model of the Boeing 737 and the results show that the optimal trajectory depends significantly on the definition of the environmental objective function. A method to treat restricted airspace is also presented and evaluated using a model of the Swedish Air Force trainer SK60. The results show that the method for imposing airspace constraints on the flight path works well, especially when the initial point for the optimization is feasible. / QC 20100720

In vehicles with electric transmission and independent wheel stations, there is apossibility to control propulsion, steering and suspension individually for eachwheel. This makes it possible to improve mobility in terrain as well as performanceand driving safety on road. This contribution concerns how a six wheeledelectric transmission vehicle should be modelled to enable evaluation of thedynamic behaviour both in terrain and on road. This is made by combiningmodelling of vehicle, transmission and tyre/terrain behaviour.A tyre/terrain model is needed to simulate driving on soft ground. Heretyre/terrain models for simulating driving with both rigid and pneumatic wheelson soft ground have been developed. A method to measure terrain parametersand drawbar pull for a six-wheeled vehicle on sand is proposed, tested andevaluated.To simulate a six wheeled vehicle at the handling limit on road, a vehicle modelwith a brush tyre model is used in order to get physically reasonable simulationresults during high combined slip conditions. Different vehicle configurationsare considered, where front wheel steering is combined with eithersecond axle steering, rear wheel steering or individual wheel torque control.By applying different vehicle slip angles and thereby limiting the DOF of thevehicle model, the vehicle configurations are evaluated during different drivingconditions. The results show that by applying individual torque control to thefront wheel steered vehicle, the performance is improved for all evaluated manoeuvres,and the achievable aligning torque during a rear wheel skid increasessignificantly if the vehicle slip angle is larger than the maximum front wheelsteering angle.To conclude, models of a six-wheeled vehicle with electric transmission andtyre models both for soft and rigid ground have been developed. These modelsform a simulation platform, which makes it possible to evaluate controlstrategies for the electric transmission with the purpose to improve mobility interrain as well as performance and driving safety on road. Some examples ofapplications of the models are included, e.g. improving at-the-limit handlingand pivot turning performance. / QC 20101026