Master of Science / Department of Industrial and Manufacturing Systems Engineering / Jessica L. Heier Stamm / Gifts-in-kind (GIK) donations negatively affect the humanitarian supply chain at the point of receipt near the disaster site. In any disaster, as much as 50 percent of GIK donations are irrelevant to the relief efforts. This proves to be a significant issue to humanitarian organizations because the quantity and type of future GIK are uncertain, making it difficult to account for GIK donations at the strategic planning level. The result is GIK consuming critical warehouse space and manpower. Additionally, improper treatment of GIK can result in ill-favor of donors and loss of donations (both cash and GIK) and support for the humanitarian organization. This thesis proposes a robust facility location approach that mitigates the impact of GIK by providing storage space for GIK and pre-positions supplies to meet initial demand. The setting of the problem is strategic planning for hurricane relief along the Gulf and Atlantic Coasts of the United States. The approach uses a robust scenario-based method to account for uncertainty in both demand and GIK donations. The model determines the location and number of warehouses in the network, the amount of pre-positioned supplies to meet demand, and the amount of space in each warehouse to alleviate the impact of GIK. The basis of the model is a variant of the covering facility location model that must satisfy all demand and GIK space requirements. A computational study with multiple cost minimizing objective functions illustrates how the model performs with realistic data. The results show that strategic planning in the preparedness phases of the disaster management cycle will significantly mitigate the impact of GIK.

Master of Science / Department of Statistics / Weixing Song / A robust estimation procedure for parametric regression models is proposed in the paper by assuming the error terms follow a Pearson type VII distribution. The estimation procedure is implemented by an EM algorithm based on the fact that the Pearson type VII distributions are a scale mixture of a normal distribution and a Gamma distribution. A trimmed version of proposed procedure is also discussed in this paper, which can successfully trim the high leverage points away from the data. Finite sample performance of the proposed algorithm is evaluated by some extensive simulation studies, together with the comparisons made with other existing procedures in the literature.

Les avions rencontrent de nombreuses conditions d’opérations au cours de leurs vols, comme le nombre de Mach, l’altitude et l’angle d’attaque. Leur prise en compte durant la conception améliore la robustesse du système et finalement la consommation des flottes d’avions. L’optimisation de formes aérodynamiques contribue à la conception des avions, et repose sur l’automatisation de la génération de géométries ainsi que la simulation numérique de la physique du vol. La minimisation de la trainée des formes aérodynamiques doit prendre en compte de multiples conditions d’opération, étant donne que l’optimisation a une unique condition de vol mène a des formes dont la performance se dégrade fortement quand cette condition de vol est perturbée. De plus, la flexibilité structurelle déforme les ailes différemment selon la condition de vol, et doit donc être simulée lors de telles optimisations. Dans cette thèse, la minimisation de la consommation de carburant au cours d’une mission est formulée en problème d’optimisation. Une attention particulière est apportée au choix des conditions d’opérations à inclure dans le problème d’optimisation, étant donne que celles-ci ont un impact majeur sur la qualité des résultats obtenus, et que le cout de calcul est proportionnel à leur nombre. Un nouveau cadre théorique est proposé pour adresser cette question, offrant un point de vue original et surmontant des difficultés révélées par les méthodes a l’état-de-l’ art en matière de mise en place de problèmes d’optimisation multipoints. Un algorithme appelé Gradient Span Analysis (GSA), est proposé pour automatiser le choix des conditions d’opération. Il est base sur la réduction de dimension de l’espace vectoriel engendre par les gradients adjoints aux différentes conditions de vol. Des contributions de programmation a la chaine d’optimisation ont permis d’évaluer les méthodes aux optimisations du profil académique RAE2822 et de la configuration voilure-fuselage XRF-1, représentative des avions de transport modernes. Alors que les formes résultant d’optimisation mono-point présentent de fortes dégradations de performance hors du point de conception, les optimisations multipoints adéquatement formulées fournissent de bien meilleurs compromis. Il est finalement montre que les interactions fluide-structure ajoutent de nouveaux degrés de liberté, et ont un impact sur les optimisations en de multiples conditions de vol, ouvrant des perspectives en matière d’adaptation passive de forme. / An aircraft encounters a wide range of operating conditions during its missions, i.e. flight altitude, Mach number and angle of attack, which consideration at the design phase enhances the system robustness and consequently the overall fleet consumption. Numerical optimization of aerodynamic shapes contributes to aircraft design, and relies on the automation of geometry generation and numerical simulations of the flight physics. Minimization of aerodynamic shapes drag must take into account multiple operating conditions, since optimization at a single operating condition leads to a strong degradation of performance when this operating condition varies. Besides, structural flexibility deforms the wings differently depending on the operating conditions, so has to be simulated during such optimizations. In the present thesis, the mission fuel consumption minimization is formulated as an optimization problem. The focus is made on the choice of operating conditions to be included in the optimization problem, since they have a major impact on the quality of the results, and the computational cost is proportional to their number. A new theoretical framework is proposed, overcoming and giving new insights on problematic situations revealed by state-of-the-art methods for multipoint optimization problem setup. An algorithm called Gradient Span Analysis is proposed to automate the choice of operating conditions. It is based on a reduction of dimension of the vector space spanned by adjoint gradients obtained at the different operating conditions. Programming contributions to the optimization chain enabled the evaluation of the new method on the optimizations of the academic RAE2822 airfoil, and the XRF-1 wing-body configuration, representative of a modern transport aircraft. While the shapes resulting of single-point optimizations present strong degradations of the performance in off-design conditions, adequately formulated multi-Machmulti- lift optimizations present much more interesting performance compromises. It is finally shown that fluid-structure interaction adds new degrees of freedom, and has consequences on multiple flight conditions optimizations, opening the perspective of passive shape adaptation.

Cette thèse porte sur les convertisseurs des liaisons à courant continu (HVDC- High Voltage Direct Current). Une nouvelle méthodologie de synthèse des régulateurs des convertisseurs basée sur un modèle de commande a été développée. Ce dernier prend en considération non seulement les deux convertisseurs de la liaison HVDC mais aussi l'ensemble des principaux éléments impactant la stabilité transitoire du système électrique dans lequel la liaison est insérée. Une commande robuste coordonnée est proposée pour, à la fois, répondre au cahier des charges de la liaison et améliorer la stabilité de la zone AC voisine à la liaison. La coordination de la synthèse de régulateurs pour les convertisseurs se fait à deux niveaux : le premier concerne les deux stations de conversion d'une même liaison HVDC et un second consistant en la coordination de plusieurs liaisons HVDC. De plus, seules les mesures disponibles localement (i.e., au niveau des stations de conversion) sont utilisées. Ce nouveau cadre de commande est une alternative à la commande vectorielle classique. L'approche a été validée à la fois sur des benchmarks académiques et en grande taille sur des cas concrets de renforcement du réseau de transport européen. / This thesis focuses on the control of converters of high voltage direct current (HVDC) links. A new methodology of synthesis of the controllers of the HVDC converters based on a control model has been developed. The latter takes into consideration not only the two converters of HVDC link but all the main dynamics affecting the transient stability of the power system in which the link is inserted. In order to improve the stability of the AC zone neighboring the HVDC link, in addition to the local objectives like power and voltage control, a coordinated robust control is proposed. The coordination of the synthesis controllers for converters is done at two levels: the first one is the coordination of the two stations of an HVDC link the second is consisting on the coordination of several HVDC links. In addition, only measures available locally (i.e., at the converter stations) are used. This new control frame is an alternative to the conventional vector control. The approach was validated on both academic benchmark and a large-scale dynamic model of the whole European power system.

In this thesis, we consider the trajectory planning of an autonomous vehicle to cross an intersection within a given time interval. The vehicle communicates its sensordata to a central coordinator which then computes the trajectory for the given time horizon and sends it back to the vehicle. We consider a realistic scenario in which the communication links are unreliable, the evolution of the state has noise (e.g., due to the model simplification and environmental disturbances), and the observationis noisy (e.g., due to noisy sensing and/or delayed information). The intersection crossing is modeled as a chance constraint problem and the stochastic noise evolution is restricted by a terminal constraint. The communication impairments are modeled as packet drop probabilities and Kalman estimation techniques are used for predicting the states in the presence of state and observation noises. A robust sub-optimalsolution is obtained using convex optimization methods which ensures that the intersection is crossed by the vehicle in the given time interval with very low chance of failure.

Cette thèse s’adresse à la problématique de contrôle/commande et d'observation des exosquelettes du membre supérieur pour l’assistance à la mobilité des personnes qui souffrent d'un déficit moteur, caractérisé par une perte totale ou partielle des capacités motrices. Le robot utilisé pour les validations est conçu par RB3D dans le but des travaux de recherches sur les lois de commandes pour la rééducation du membre supérieur au sien du Laboratoire LISSI (Laboratoire Images, Signaux et Systèmes Intelligents) de l’UPEC, appelé ULEL (Upper Limb Exoskeleton of LISSI).Deux approches de commande d'exosquelettes pour la rééducation fonctionnelle du membre supérieur ont été proposées. La première commande est conçue sur la base d’un estimateur en-ligne des paramètres dynamiques. Cette méthode d'adaptation permet d'améliorer les performances de contrôle de ce système, et de compenser les erreurs paramétriques dues au couplage de l'exosquelette avec le membre humain.La deuxième contribution consiste en une stratégie de commande robuste basée sur les modes glissants. Cette stratégie non-linéaire, garantie la convergence des erreurs de poursuite vers zéro en temps fini lorsque le régime de glissement est atteint. Ce type de commande est connu par sa robustesse vis-à-vis les variations paramétriques et les perturbations externes. L'efficacité de la méthode proposée est démontrée expérimentalement pour le mode de rééducation passif.Dans la dernière partie de la thèse, un observateur en mode glissant d'ordre supérieur est proposé pour estimer les couples d'interactions homme-exosquelette. L'observateur proposé est capable d'estimer les efforts au niveau de l'interface d'interaction entre l'exosquelette et le membre humain, en utilisant les mesures de position et l'entrée de commande. Les résultats obtenus montrent l’efficacité des solutions proposées sur l’exosquelette ULEL. / This thesis addresses the problem of control of an upper limb exoskeleton for mobility assistance of people who suffer from a motor deficit, characterized by a total or partial loss of motor skills. The robot used is designed by RB3D for the purpose of research work on the control laws for the rehabilitation of the upper limb at LISSI Laboratory (Laboratory Images, Signals and Intelligent Systems) of the UPEC university; this exoskeleton is called ULEL (Upper Limb Exoskeleton of LISSI).Two approaches to control exoskeletons for functional rehabilitation of the upper limb have been proposed. The first control is based on an online estimator of dynamic parameters. This adaptation method makes it possible to improve the control performance of this system, and to compensate for parametric errors due to coupling the exoskeleton with the human limb.The second contribution consists of a robust control strategy based on sliding modes. This nonlinear strategy guarantees the convergence of tracking errors to zero in finite time when the sliding mode is reached. This type of control is known by its robustness with respect to parametric variations and external disturbances. The effectiveness of the proposed method is experimentally demonstrated for the passive rehabilitation mode.Finally, in the last part of this thesis, a higher order sliding mode observer is proposed to estimate interactions torques of the human-exoskeleton system. The proposed observer is able to estimate the forces at the interaction interface between the exoskeleton and the human limb, using the position measurements and the control input. The obtained results show the effectiveness of the proposed solutions using the exoskeleton ULEL.

À l'aube de la quatrième révolution industrielle, la comanipulation robotique est une technologie clé tant elle allie la dextérité de l'opérateur humain à la puissance de la machine. Ce partage de tache entre humain et la machine, en sus dans un environnement incertain et inconnu à l'avance, apporte un lot de difficultés intrinsèques à la nature de cette interaction. Cette problématique a été intensivement étudiée durant les vingt dernières années, par diverses équipes de recherches, le plus souvent sur des dispositifs à un seul degré de liberté et avec des hypothèses fortes sur la nature du contrôleur. Dans la présente thèse, nous traitons la problématique de la comanipulation robotique à travers la commande Hoo structurée, cadre de travail particulièrement adapté aux systèmes multivariables et pouvant être étendu à une certaine classe de systèmes non linéaires – les robots manipulateurs en font partie – à travers une modélisation linéaire à paramètres variants (LPV). Les exigences de performance et de stabilité propres aux systèmes de comanipulation sont exprimées en termes de contraintes Hoo et de conditions de secteurs à respecter. Les objectifs de commande ainsi formalisés, sont résolus par optimisation non lisse afin de tirer profit des structures particulières des contrôleurs de robots de comanipulation. La validation de la méthodologie est réalisée par des simulations intensives et des expérimentations sur des dispositifs réels. / At the dawn of the fourth industrial revolution, robotic comanipulation is a key technology as it combines the dexterity of the human operator with the power of the machine. This task sharing between human and machine, in an uncertain and previously unknown environment, brings a lot of intrinsic difficulties to the nature of this interaction. This problem has been intensively studied over the last two decades by various research teams, mostly on devices with a single degree of freedom and with strong hypotheses about the controller structure. In this thesis, we deal with the problem of robotic comanipulation through the scope of the structured Hoo control, a framework particularly adapted to multivariable systems and which can be extended to a certain class of non-linear systems – manipulating robots are part of it – through linear parameter varying (LPV) models. The performance and stability requirements specific to comanipulation systems are expressed in terms of Hoo constraints and sector bounds. The control objectives thus formalised are solved by non-smooth optimization in order to take advantage of the particular structures of the comanipulation robot controllers. The validity of the methodology is carried out by intensive simulations and experiments on real devices.

The Swedish car manufacturer, Volvo Cars, are a pioneer in the automotive industry regarding vehicle safety. Ever since they invented the three-point seat belt, the safety aspect has been their main priority. Today, a car is equipped with new technology and is highly dependent on software solutions. This implies that software features are used to increase the safety of the car. The level of uncertainty increases with the new features, which highlights the importance of creating a robust product to avoid potential problems. During the last decade, the DCOV approach (Define – Characterize – Optimize – Verify) evolved to create a product that is insensitive to variation and appreciated by the customers. Volvo Cars are currently developing a camera monitoring system (CMS) that is supposed to replace the conventional rear-view mirror with an exterior camera and an interior display. The purpose of this master’s thesis is to develop a robust design for the CMS that satisfies the customers. By using the DCOV approach, the aim is to identify potential risks and failure modes to avoid hardware and software related problems, and at the same time, develop a product that is based on the voice of the customer. This thesis demonstrates the problems with the conventional mirrors and the parking assistance cameras, which are associated with the folding function, the mirror adjustment, and the wide-angle module. The analysis of customer surveys indicates that blind spot indicators are appreciated by the customers while the mirror size is a critical factor. The mirrors need to be large enough to provide a good rear-view visibility, but small enough to maintain good forward visibility. A parameter diagram, robustness checklist and a system failure mode and effect analysis (S-FMEA) were conducted to identify risks, noise factors and failure modes with the CMS. It resulted in 44 failure modes where six of them were considered as critical, which means a high level of severity or frequent occurrence. The six critical failure modes were identified at the S-FMEA meetings with the business units Manufacturing, Display systems, Electromagnetic compatibility and CMS camera. Three business units were software related, which shows the difficulties with the transition from a hardware related rear-view mirror to the CMS. The recommendations for Volvo Cars are divided into two categories, where the first is associated with the CMS and should be seen as a continuation of this thesis. Volvo Cars should complete the S-FMEA and the included actions. By conducting the recommendations for the CMS, it will be properly tested to resist noise factors and manage potential variation. The long-term recommendations are proposals for future actions, which include a CMS for the inner mirror and investigate BLIS options. If the recommendations are considered, it will increase the possibility of creating a robust design, based on the voice of the customer. The result of this study highlights the power of the DCOV approach, as it clearly shows that it is possible to reduce the warranty costs. If the folding function is excluded, and the CMS software becomes easy to update, the warranty costs could be reduced by SEK 5 million.

Examensarbetets mål är att utveckla och konstruera en ny uppkopplingslösning för motorer som genomgår kvalitetssäkring hos Volvo Lastvagnar. Examensarbetet är genomfört som den avslutande delen av studierna på maskiningenjörsprogrammet på Högskolan i Skövde. Ökade kundkrav på tillverkningsföretag har lett till ökade krav på individanpassade produkter. Detta sätter större krav på produktvariationer som i sin tur leder till produktionsvariationer. Volvo Lastvagnar tillverkar idag en stor mängd motorvarianter som ställer ökade krav på en mer flexibel anslutningslösning för att koppla upp dessa motorvarianter för kvalitetssäkring och testkörning. Dagens uppkopplingslösning är bristfällig, improviserad och icke flexibel. Volvo Lastvagnar har uttryckt en önskan att förbättra uppkopplingen av turboaggregatets avgashus vid kvalitetssäkringsprocessen inför en effektivisering av motorprovet. Projektet inleddes med en omfattande litteraturstudie för att undersöka hur produktionsvariation och krav på en mer flexibel uppkoppling kan lösas genom produktdesign. Variationerna som påverkade uppkopplingen mellan de olika motorerna kartlades och lades som grund för vidare arbete. Flertalet koncept gällande hantering av motorvariatoner togs fram och utvärderades med hjälp av 3D-printade prototyper. Ett slutgiltigt koncept beräknades, dimensionerades och konstruerades. Resultatet visade att det går att möta den stora produktionsvariationen med hjälp av robust design. Resultatet visade också att dagens uppkoppling är överdimensionerad och bristfällig. Författarna till denna rapport rekommenderar Volvo Lastvagnar att fortsätta arbetet med att implementera uppkopplingslösningen i produktion för att utföra verkliga tester och optimera lösningen ytterligare. / The goal of the thesis work is to develop and construct a new solution for connecting engines that goes through a quality check at the testing facility at Volvo Trucks. The thesis work is the final segment of the mechanical engineering program at the University of Skövde. Growing demands within manufacturing have led to higher requirements regarding customized products. This puts a higher demand on product variety which leads to greater varieties in production. Volvo Trucks manufactures a variety of engines which requires a more flexible way of connecting these different types of engines in the testing facility for testing and quality checks. The current state of this connection is inadequate, improvised and non-flexible. Volvo Trucks have expressed a wish to improve the quality- and testing process regarding the exhaust connection of the engines, as Volvo Trucks are planning a future reconstruction of the testing facility. The project started by performing an extensive literature review to investigate how variety in production and demands for a more flexible connection can be solved through product design. The variations that affected the connection between the different motor types and the testing facility were documented and used as a foundation for further work. A number of concepts regarding the handling of the different motor types were developed and reviewed with 3D-printed prototypes. A final concept was calculated, dimensioned and constructed. The result shows that it is possible to handle the vast variation in production with the help of robust design. The result also showed that the present connections are oversized and insufficient. The authors of this report recommend that Volvo Trucks should continue with implementing the new connection in production to perform tests and develop this connection further.

Observações ou outliers estão quase sempre presentes em qualquer conjunto de dados, seja ele grande ou pequeno. Isso pode ocorrer por erro no armazenamento dos dados ou por existirem realmente alguns pontos diferentes dos demais. A presença desses pontos pode causar distorções nos resultados de modelos e estimativas. Por isso, a sua detecção é muito importante e deve ser feita antes do início de uma análise mais profunda dos dados. Após esse diagnóstico, pode-se tomar uma decisão a respeito dos pontos atípicos. Uma possibilidade é corrigi-los caso tenha ocorrido erro na transcrição dos dados. Caso sejam pontos válidos, eles devem ser tratados de forma diferente dos demais, seja com uma ponderação, seja com uma análise especial. Nos casos univariado e bivariado, o outlier pode ser detectado analisando-se o gráfico de dispersão que mostra o comportamento de cada observação do conjunto de dados de interesse. Se houver pontos distantes da massa de dados, eles devem ser considerados atípicos. No caso multivariado, a detecção por meio de gráficos torna-se um pouco mais complexa porque a análise deveria ser feita observando-se duas variáveis por vez, o que tornaria o processo longo e pouco confiável, pois um ponto pode ser atípico com relação a algumas variáveis e não ser com relação a outras, o que faria com que o resultado ficasse mascarado. Neste trabalho, alguns métodos robustos para detecção de outliers em dados multivariados são apresentados. A aplicação de cada um dos métodos é feita para um exemplo. Além disso, os métodos são comparados de acordo com o resultado que cada um apresentar para o exemplo em questão e via simulação. / Unusual observations or outliers are frequent in any data set, if it is large or not. Outliers may occur by typing mistake or by the existence of observations that are really different from the others. The presence of this observations may distort the results of models and estimates. Therefore, their detection is very important and it is recommended to be performed before any detailed analysis, when a decision can be taken about these atypical observations. A possibility is to correct these observations if the problem occurred with the construction of the data set. If the observations are correct, different strategies can be adopted, with some weights or with special analysis. In univariate and bivariate data sets, outliers can be detected analyzing the scatter plot. Observations distant from the cloud formed by the data set are considered unusual. In multivariate data sets, the detection of outliers using graphics is more difficult because we have to analyse a couple of variables each time, which results is a long and less reliable process because we can find an observation that is unusual for one variable and not unusual for the others, masking the results. In this work, some robust methods for detection of multivariate outliers are presented. The application of each one is done for an example. Moreover, the methods are compared by the results of each one in the example and by simulation.