In this study, CFD simulations of a complete truck are carried out to investigate the effect of altered simulation settings at cold climatic conditions. The aim of this study is to obtain knowledge through CFD simulations performed on a selected driving condition namely at a vehicle speed of 93 kph, an ambient temperature of -20 °C and for an engine operating at 25 % load. Data from measurement carried out in a climatic wind tunnel is available and utilized as boundary conditions for the simulations.The simulations are performed under steady state conditions utilizing the commercial software STAR-CCM+. The first simulation case (reference simulation case) is constructed through java macro-scripts as per the standard VTM settings at Scania. The results from the simulations are compared with the measurement data utilizing temperature validation probes. These probes are located around the engine and measure the air temperature in the underhood engine compartment. The results from the first simulation case show that the temperature of each probe located in front of the engine and above the engine agrees well with the measured probe temperatures. But the temperature of the remaining probes show larger differences with the measured probe temperatures. To investigate the larger differences in probe temperatures, additional simulations are carried out by changing specific simulation settings. For instance, this is achieved by including thermal radiation in the physics continua. Finally, a simulation of engine load of 100 % is carried out and the results from the simulation are compared with the measurement from the same engine load as well as the results from the measurement and simulation of 25 % engine load. The results from all the simulations indicate that additional boundaryconditions and/or different methodologies need to be explored to better replicate the cold climatic conditions in the simulations.

The new emission regulations for new trucks was made to decrease the CO2 emissions by 30% from 2020 to 2030. One of the solutions is hybridizing the truck powertrain with 48V or 600V that can recover brake energy with electrical machines and batteries. The control of this hybrid powertrain is key to increase fuel efficiency. The idea behind this approach is to combine two different power sources, an internal combustion engine and a battery driven electric machine, and use both to provide tractive forces to the vehicle. This approach requires a HEV controller to operate the power flow within the systems. The HEV controller is the key to maximize fuel savings which contains an energy management strategy. It uses the knowledge of the road profile ahead by GPS and maps, and strongly interacts with the control of the cruise speed, automated gear shifts, powertrain modes and state of charge. In this master thesis, the dynamic programming strategy is used as predictive energy management for hybrid electric truck in forward- facing simulation environment. An analysis of predictive energy management is thus done for receding and full horizon length on flat and hilly drive cycle, where fuel consumption and recuperation energy will be regarded as the primary factor. Another important factor to consider is the powertrain mode of the vehicle with different penalty values. The result from horizon study indicates that the long receding horizon length has a benefit to store more recuperative energy. The fuel consumption is decreased for all drive cycle in the comparison with existing Volvo’s strategy.

The automotive industry is undergoing a revolution where the more traditional mechanical values are replaced by an ever increasing number of Advanced Driver Assistance Systems (ADAS) where advanced algorithms and software development are taking a bigger role. Increased safety, reduced emissions and the possibility of completely new business models are driving the development and most automotive companies have started projects that aim towards fully autonomous vehicles. For industrial applications that provide a closed environment, such as mining facilities, harbors, agriculture and airports, full implementation of the technology is already available with increased productivity, reliability and reduced wear on equipment as a result. However, it also gives the opportunity to create a safer working environment when human drivers can be removed from dangerous working conditions. Regardless of the application an important part of any mobile autonomous system is the motion planning layer. In this thesis sampling-based motion planning algorithms are used to solve several non-holonomic and kinodynamic planning problems for car-like robotic vehicles in different application areas that all present different challenges. First we present an extension to the probabilistic sampling-based Closed-Loop Rapidly exploring Random Tree (CL-RRT) framework that significantly increases the probability of drawing a valid sample for platforms with second order differential constraints. When a tree extension is found infeasible a new acceleration profile that tries to brings the vehicle to a full stop before the collision occurs is calculated. A resimulation of the tree extension with the new acceleration profile is then performed. The framework is tested on a heavy-duty Scania G480 mining truck in a simple constructed scenario. Furthermore, we present two different driver assistance systems for the complicated task of reversing with a truck with a dolly-steered trailer. The first is a manual system where the user can easily construct a kinematically feasible path through a graphical user interface. The second is a fully automatic planner, based on the CL-RRT algorithm where only a start and goal position need to be provided. For both approaches, the internal angles of the trailer configuration are stabilized using a Linear Quadratic (LQ) controller and path following is achieved through a pure-pursuit control law. The systems are demonstrated on a small-scale test vehicle with good results. Finally, we look at the planning problem for an autonomous vehicle in an urban setting with dense traffic for two different time-critical maneuvers, namely, intersection merging and highway merging. In these situations, a social interplay between drivers is often necessary in order to perform a safe merge. To model this interaction a prediction engine is developed and used to predict the future evolution of the complete traffic scene given our own intended trajectory. Real-time capabilities are demonstrated through a series of simulations with varying traffic densities. It is shown, in simulation, that the proposed method is capable of safe merging in much denser traffic compared to a base-line method where a constant velocity model is used for predictions.

Scania CV is a premium truck, bus and engine manufacturer. At Scania there is a research and development department, in the thesis referred to as the R&D department, which delivers ITtool solutions for internal customers at Scania. After a new IT-tool has been implemented The R&D department want to be able to evaluate the benefits enabled by the IT-tool. Today the R&D department mainly identifies tangible benefits such as improved quality, saved time and saved money due to the use of a new IT-tool. The R&D department have expressed that they see room for improvement both in the phase of prioritizing between what IT-tool projects to start and in the evaluation of IT-tools. Scania often prioritize product development projects for external customers before IT-tool development projects for internal customers. The R&D department believes that the position of IT-tool projects for internal customer could be strengthen if a more comprehensive IT-tool evaluation could be implemented. This way a better case could be made to emphasize the importance of prioritizing new IT-tool projects for internal customers. The purpose of this master thesis is to create a tool to manage benefits and disbenefits of IT-tools by making the R&D department able to identify, categorize, rank and evaluate benefits and disbenefits enabled by IT-tools. The result of the thesis has been found through a literature study, multiple workshops, and semi structured interviews with employees linked to two different IT-tools A and –B together with validation in an improvement group linked to another IT-tool C. The result of the thesis is known as the IT-Tool Evaluator and consists of a list of benefit aspects with corresponding weights. Two surveys and a calculation template has been developed with the purpose to quantify how a new IT-tool fulfils these benefit aspects. One survey focus on the IT-tool user and one survey has a focus of a company perspective. The benefit aspects are visualised using radar diagrams, a score for each aspect is calculated and a total score for the IT-tool is generated. The difference in score in each of the 22 benefit aspects in the new IT-tool and the IT-tool that is being replaced decides if the new IT-tool brings a positive change (benefit) or negative change (disbenefit) in the given aspect. / Scania CV är en premiumtillverkare av lastbilar, bussar och motorer. På Scania finns en forsknings och utvecklingsavdelning, i det här examensarbetet refererad till som R&Davdelningen, som hanterar IT-verktygslösningar för interna kunder på Scania. Efter att ett nytt IT-verktyg har implementerats vill R&D-avdelningen kunna utvärdera vilka fördelar som möjliggjorts genom det nya IT-verktyget. Idag ser R&D-avdelningen huvudsakligen till påtagliga fördelar så som förbättrad kvalité, sparad tid och sparade pengar som resultat av ett nytt IT-verktyg. R&D-avdelningen har uttryckt att de ser förbättringspotential både i deras förmåga att prioritera mellan IT-verktygsprojekt och utvärdering av IT-verktygen som följer. Idag prioriterar Scania ofta produktutvecklingsprojekt för externa kunder före utvecklingsprojekt av IT-verktyg för interna kunder. R&D-avdelningen är av uppfattning att detta kunde förändras om det fanns ett bättre sätt att hantera påtagliga och opåtagliga fördelar som möjliggörs genom IT-verktyg. På detta vis skulle resultaten ifrån IT-verktygsprojekt bättre kunna jämföras med fördelarna som genereras med produktutvecklingsprojekt för externa kunder. Syftet med masteruppsaten är att skapa ett verktyg som hanterar fördelar och nackdelar av IT-verktyg för att göra R&D-avdelningen bättre på att identifiera, kategorisera, ranka och utvärdera fördelar och nackdelar som möjliggörs genom IT-verktyg. Resultatet av uppsatsen har tagits fram med hjälp av litteraturstudie, flertalet workshops och semistrukturerade intervjuer med Scania-anställda med kopplingar till två olika IT-verktyg samt en validering i en förbättringsgrupp kopplad till ett tredje IT-verktyg. Resultatet som döpts till ITverktygsutvärderaren består av en lista med 22 olika aspekter av potentiella nackdelar och fördelar med IT-verktyg som kategoriserats in i fyra huvudkategorier där varje aspekt har en tillhörande viktning. Två enkäter och en beräkningsmall har tagits fram med syfte att kvantifiera hur IT-verktyget uppfyller dessa aspekter. En enkät fokuserar på användaren av IT-verktyget och den andra enkäten har ett mer övergripande företagsperspektiv. De 22 oviktade aspekterna i kategorierna visualiseras med hjälp av spindeldiagram, en summa poäng räknas fram för varje kategori och en totalpoäng för IT-verktyget tas fram. Skillnaden i poäng i de 22 aspekterna mellan det nya IT-verktyget och det ersatta IT-verktyget bestämmer om det nya IT-verktyget medför en positiv förändring (fördel) eller negativ förändring (nackdel) i den givna aspekten.

This thesis work presents a model predictive control (MPC) based trajectory planner forhigh speed lane change and low speed parking scenarios of autonomous four wheel steering(4WS) vehicle. A four wheel steering vehicle has better low speed maneuverabilityand high speed stability compared with normal front wheel steering(FWS) vehicles. TheMPC optimal trajectory planner is formulated in a curvilinear coordinate frame (Frenetframe) minimizing the lateral deviation, heading error and velocity error in a kinematicdouble track model of a four wheel steering vehicle. Using the proposed trajectory planner,simulations show that a four wheel steering vehicle is able to track different type ofpath with lower lateral deviations, less heading error and shorter longitudinal distance. / I detta avhandlingsarbete presenteras en modellbaserad prediktiv kontroll (MPC) -baseradbanplaneringsplan f¨or h¨oghastighetsbanan och l°aghastighetsparametrar f¨or autonomtfyrhjulsdrift (4WS). Ett fyrhjulsdrivna fordon har b¨attre man¨ovrerbarhet med l°ag hastighetoch h¨oghastighetsstabilitet j¨amf¨ort med vanliga fr¨amre hjulstyrningar (FWS). MPC-optimalbanplanerare ¨ar formulerad i en kr¨okt koordinatram (Frenet-ram) som minimerar sidof¨orl¨angningen,kursfel och hastighetsfel i en kinematisk dubbelsp°armodell av ett fyrhjulsstyrda fordon.Med hj¨alp av den f¨oreslagna banaplaneraren visar simuleringar att ett fyrhjulsstyrfordonkan sp°ara olika typer av banor med l¨agre sidof¨orl¨angningar, mindre kursfel ochkortare l¨angsg°aende avst°and.

In this thesis, support structures of a polymer powder based process called XXXXXXXX™ are examined. These structures are crucial for most additive manufacturing processes. The effects of several factors on five industrially important characteristics of support structures are examined by use of the Design of Experiment (DoE) method. It describes the planning as well as the analysis of the experiments. The experiments are planned in a fractional factorial 211-5 design with 64 specimens, resulting in a resolution of IV. The analysis of the data is done by use of the ANOVA method, with which the significance of effects and interaction effects are checked. / I detta examensarbete undersöks stödstrukturer för en polymer-pulverbaserad process kallad XXXXXXXX. Dessa strukturer är väsentliga för de flesta aditiv tillverkning. Med hjälp av metoden "Design of Experiment" (DoE) undersöks effekten av flera faktorer på fem industriellt viktiga egenskaper för stödstrukturer. DoE beskriver både planeringen och analysen av experiment. Experimenten planeras i en fraktionerad faktoriell 211-5 design med 64 provexemplar vilket resulterar i en upplösning av IV. Dataanalysen genomförs med hjälp av ANOVA-metoden, med vilken signifikansen av effekter och interaktionseffekter kan undersökas.

In most application to date reinforced carbon fiber composites have been used in relatively smaller thickness, less than 10mm thick and essentially for carrying in-plane loads. As a result, design and testing procedures were developed which reflected the need to understand the in-plane response of the material. recently, engineers and designers have begun to use reinforced carbon fiber composites in thicker sections, where an understanding of the through-thickness response is of para-mount importance in designing reliable structures, particularly where the through-thickness strength has a controlling influence on the overall structural strength of the component. In this thesis tests will be done on carbon fiber non-crimp fabric (NCF) which will be loaded in compression and shear and elastic moduli and strength will be evaluated. In characterizing the through-thickness mechanical properties of a composite, the objective is to produce a state of stress in the test specimen which is uniform and will repeatedly measure the true properties with accuracy. In this study, specimens were machined from two blocks of thick (~20 mm) laminates of glass/epoxy and NCF carbon fiber infused with vinylester and tested in compression, and shear.

This thesis investigated the impact performance of CFRP products within the sports industry. The primary aim of this thesis was to evaluate different configurations, matrix system, and technologies to find the best performing solutions for impact. During this work, an extensive literature study was conducted and various solutions were reviewed. Further on, several tubes were manufactured, impacted and put through a 2 point bending test to find out the residual strength. It was found that TeXtreme R fabrics positively affected the impact performance when compared to conventional fabrics and UD depending on the placement location. Thin plies proved to be better than conventional plies. Newer technologies such as CNT stitching requires further investigation before it can be qualitatively assessed.

For a successful design of an engineering system it is essential to pay careful attention to its dynamic response. This is particularly true, in the case of nonlinear systems, since they can exhibit very complex dynamic behaviour, including multiple co-existing stable solutions and chaotic motions, characterized by large sensitivity to initial conditions. In some systems nonlinear characteristics are desired and designed for, but in other cases they are unwanted and can cause fatigue and failure. A type of dynamical system which is highly nonlinear is discontinuous or non-smooth systems. In this work, systems with impacts are primarily investigated, and this is a typical example of a discontinuous system. To enhance or optimize the performance of dynamical systems, some kind of control can be implemented. This thesis concerns implementation of low-cost control strategies for discontinuous systems. Low-cost control means that a minimum amount of energy is used when performing the control actions, which is a desirable situation regardless of the application. The disadvantage of such a method is that the performance might be limited as compared with a control strategy with no restrictions on energy consumption. In this work, the control objective is to enforce a continuous or discontinuous grazing bifurcation of the system, whichever is desirable. In Paper A, the dynamic response and bifurcation behaviour of an impactoscillator with dry friction is investigated. For a one-degree-of-freedom model of the system, analytical solutions are found in separate regions of state space. These are then used to perform a perturbation analysis around a grazing trajectory. Through the analysis, a condition on the parameters of the system is derived, which assures a continuous grazing bifurcation. It is also shown that the result has bearing on the dynamic response of a two-degree-of-freedom model of the system. A low-cost active control strategy for a class of impact oscillators is proposed in Paper B. The idea of the control method is to introduce small adjustments in the position of the impact surface, at discrete moments in time, to assure a continuous bifurcation. A proof is given for what control parameters assures the stabilization. In Paper C, the proposed low-cost control method is implemented in a quarter-car model of a vehicle suspension, in order to minimize impact velocities with the bumpstop in case of high amplitude excitation. It is shown that the control method is effective for harmonic road excitation. / QC 20101118

With this contribution to the AVT-113/VFE-2 task group it was possible to prove the feasibility of high Reynolds number CFD computations to resolve and thus better understand the peculiar dual vortex system encountered on the VFE-2 blunt leading edge delta wing. Initial investigations into this phenomenon seemed to undermine the hypothesis, that the formation of the inner vortex system relies on the laminar state of the boundary layer at separation onset. As a result of this research, this initial hypothesis had to be expanded to account also for high Reynolds number cases, where a laminar boundary layer status at separation onset could be excluded. Furthermore, the data published in the same context shows evidence of secondary separation under the inner primary vortex. This further supports the supposition of a different generation mechanism of the inner vortical system other than a pure development out of a possibly laminar separation bubble. The unsteady computations performed on numerical grids with different levels of refinement led furthermore to the establishment of internal guidelines specific to the DES approach. / QC 20101111