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  • 201.
    TANG, Yihao
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Fordonsdynamik.
    ZHU, Hui
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Fordonsdynamik.
    Test method development by use of SOM-GRNN2018Självständigt arbete på avancerad nivå (masterexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [sv]

    Relationen mellan målmetri (OM) och subjektiv bedömning (SA) har analyserats av personer som använder olika metoder. I detta dokument fortsätter Gaspar Gil Gómezs forskning kring testmetodutveckling med hjälp av SOM-GRNN, som syftar till att finna korrelationer mellan OM och SA. I detta papper utförs CAE-simulering för att analysera förhållandet mellan OM och fordonsparametrar. Första intryckstestet är raffinerat och ytterligare en dataset har lagts till för att fylla i SOM-GRNN-kartan. I detta dokument analyseras även SOM- och GRNN-algoritmer, och undersöker flera möjliga tillämpningar med hjälp av SOM-GRNN kartan. Slutligen är hela SOM-GRNN-systemet integrerat och ett användargränssnitt är byggt i GUI för framtida forskning och tillämpning. Systemet kan fortfarande förbättras genom att fylla i databasen, förädla SA utvärderingsmetod och optimera SOM-GRNN träningsalgoritmer.

  • 202.
    Tidlund, Matthias
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Fordonsdynamik.
    Angelis, Stavros
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Fordonsdynamik.
    Optimal steering control input generation for vehicle's entry speed maximization in a double-lane change manoeuvre2013Självständigt arbete på avancerad nivå (masterexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [sv]

    Under utvecklingsprocessen av nya fordon sker en strävan mot att reducera fysiska tester, bilindustrier utvecklar därför metoder för att återskapa fysiska testscenarier i virtuella miljöer med hjälp av simuleringsmjukvara. Denna studie har som målsättning att utveckla en metod, med vilken fordonets dynamiska egenskaper kan utvärderas utan att utföra fysiska tester. Målet är att utveckla ett simuleringsverktyg som, i en tidig utvecklingsfas, kan användas av fordonsindustrin och som skulle införa både modifikations- och kalibreringsmöjligheter i detta skede.

    Såväl en fordonsmodell som ett anti-sladd system är konstruerat och modellens prestanda i ett dubbelt filbyte, specificerat i ISO3888 del 2, är utvärderad. Då bilens dynamiska prestanda klassificeras utifrån ingångshastigheten i detta test utfördes en optimeringsprocess där hjulens styrvinklar reglerades för att uppnå högsta möjliga hastighet vid testets startposition, detta för att separera fordonets dynamiska klassificering från mänsklig inverkan.

    Processen att konstruera fordonsmodellen utfördes med succesivt ökande antal av fordonsegenskaper, från en enkel implementering av en linjär cykel-modell till en tvåspårs-modell med krängning, transienta däckegenskaper, hjulupphängningsegenskaper samt ett anti-sladd system. Resultatet av den optimerade styrregleringen testades i motsvarande fordon på en testbana varefter modellen kunde utvärderas med det verkliga testet som referens.

    Genom en utökad möjlighet till simulering kan detta verktyg ge möjligheten att studera fler scenarier såväl som alternativa modelleringskonfigurationer; det kan reducera fysiska tester då fordons dynamiska prestanda ska klassificeras, studeras samt utvärderas.

  • 203.
    Tieri, Roberto
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Fordonsdynamik.
    Innovative active control strategies for pantograph catenary interaction2012Självständigt arbete på avancerad nivå (masterexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [en]

    The pantograph - catenary interaction is one of the most important features in high speed trains, and to guarantee a reliable current collection is the target that every railway system must take into consideration in order to speed up trains. The problem that goes against this direction is mainly the variation of the overhead equipment's stiness.

    To understand the phenomenon a lumped mass model of the pantograph with a rigid body attached to the ground representing the contact wire were built up; in this way a complete lumped mass model is developed. All information regarding both wire and pantograph set up is introduced as lumped parameters. Creating the model, dierent active control strategies as ideal control, PID control and optimal control are introduced. All simulations are made in GENSYS, while the control part is made inSIMULINK; a connection between those two softwares was created as part of the thesis using TCP/IP protocol.

    Results compared to experimental acquisition are satisfactory in terms of contact force representation. The standard deviation and average value's errors of the contact force are lower than 10%; regarding the control system, typically 20% of reduction of the standard deviation compared to the passive case is achieved.

    Also a comparison with a nite element program is done in order to better understand the limits of the model compared with a more sophisticated one. The comparison shows a good accordance up to 60 % of the average speed of the wave propagation in the catenary. The last feature analyzed is how the behavior of the controlled system changes introducing a real actuator: results shows that the performance is reduced in dierent ways considering dierent speeds, but no instabilities occur.

  • 204.
    Tomner, Petter
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Fordonsdynamik. KTH, Skolan för industriell teknik och management (ITM), Centra, Integrated Transport Research Lab, ITRL.
    Design and implementation of control and actuation for an over-actuated research vehicle2015Självständigt arbete på avancerad nivå (masterexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [en]

    AbstractThe RCV is a four wheel drive and steer electrical vehicle developed and built by the Transport Lab at KTH Royal Institute of Technology. It is fully steer-by-wire and each wheel can be individually controlled, both with regard to steering angle, as well as camber and driving torque.The RCV is planned to be used as a common platform for different fields of research, as a rolling laboratory to implement and evaluate research with.In this report the specification and functionalities of the RCV are reviewed and its data collection capabilities are validated and evaluated through classic vehicle dynamic analyses such as circle tests, step steer and roll out tests. Also, some more experimental functionalities such as simple torque vectoring, toe sweep and steering by joystick, as proof of concept of the RCV as a research and prototyping platform.Finally, some suggestions for further developments for the RCV platform are presented.

  • 205.
    Travers, Vincent
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Fordonsdynamik.
    Instability issues of an agriculturaltire testing convoy2013Självständigt arbete på avancerad nivå (masterexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [en]

    Michelin develops and manufactures tires. To check their tire, different tires tests are used.

    During the testing process of agricultural tires, some endurance tests are performed on a

    circular test track where a convoy, made of a truck pulling two single-axle trailers without

    suspension system, is driven at a constant speed. Depending on the tested tires, it has been

    observed that the convoy may become severely instable. This instability is a large problem

    for the test team since the tires undertake too much overload which makes test results

    unexploitable. This is time consuming and expensive for the company.

    The aim of this thesis is two-folded. The first aim is to identify the phenomenon causing the

    instability from experimental data and also the parameters which influence the

    phenomenon. The second aim is to model the phenomenon from technical data in order to

    predict instability behaviors in advance.

    Models have been developed and the behavior have been analyzed and compared with

    experiments. The main result of this work is that the instable behavior is due to the

    excitation of natural modes of the convoy by the tires frequencies. Natural modes are

    identified as the natural bouncing mode of the trailers. The bouncing natural mode of a

    trailer depends on tires stiffnesses and the load on the trailer. Tires excitation frequencies

    are related to the test speed, the trailer track width and the rolling circumference of the

    tires. To get a good prediction tires stiffness and tires rolling circumference under operation

    require to be better characterized.

    Thanks to this work the test teams have a better understanding of the phenomenon and a

    tool which can be used to give a rough indication about problematic configurations. This tool

    cannot totally predict instable behaviors with the technical data at our disposal since some

    more parameters, which are not quantified for now, might influence the phenomenon.

    Nevertheless, these parameters have been highlighted by this study and if explored by the

    test team, a working predicting tool could be achieved.

  • 206.
    Tyskeng, Sara
    et al.
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Samhällsplanering och miljö, Miljöstrategisk analys. KTH, Skolan för teknikvetenskap (SCI), Centra, VinnExcellence Center for ECO2 Vehicle design.
    Jerrelind, Jenny
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Fordonsdynamik. KTH, Skolan för teknikvetenskap (SCI), Centra, VinnExcellence Center for ECO2 Vehicle design.
    Boij, Susann
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, MWL Strömningsakustik. KTH, Skolan för teknikvetenskap (SCI), Centra, VinnExcellence Center for ECO2 Vehicle design.
    Efraimsson, Gunilla
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Aeroakustik. KTH, Skolan för teknikvetenskap (SCI), Centra, VinnExcellence Center for ECO2 Vehicle design.
    Wennhage, Per
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Lättkonstruktioner. KTH, Skolan för teknikvetenskap (SCI), Centra, VinnExcellence Center for ECO2 Vehicle design.
    Berg, Mats
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Spårfordon. KTH, Skolan för teknikvetenskap (SCI), Centra, VinnExcellence Center for ECO2 Vehicle design.
    Göransson, Peter
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, MWL Numerisk akustik. KTH, Skolan för teknikvetenskap (SCI), Centra, VinnExcellence Center for ECO2 Vehicle design.
    Centre for ECO2 Vehicle Design: vehicle design research for more environmentally friendly and economically competitive vehicles2008Ingår i: The Vehicle Component, SVENartikelArtikel i tidskrift (Övrig (populärvetenskap, debatt, mm))
  • 207.
    Wang, Zexu
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Fordonsdynamik.
    Trajectory Planning for Four WheelSteering Autonomous Vehicle2018Självständigt arbete på avancerad nivå (masterexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [sv]

    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.

  • 208.
    Wanner, Daniel
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Fordonsdynamik.
    Controlling over-actuated road vehicles during failure conditions2015Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    The aim of electrification of chassis and driveline systems in road vehicles is to reduce the global emissions and their impact on the environment. The electrification of such systems in vehicles is enabling a whole new set of functionalities improving safety, handling and comfort for the user. This trend is leading to an increased number of elements in road vehicles such as additional sensors, actuators and software codes. As a result, the complexity of vehicle components and subsystems is rising and has to be handled during operation. Hence, the probability of potential faults that can lead to component or subsystem failures deteriorating the dynamic behaviour of road vehicles is becoming higher. Mechanical, electric, electronic or software faults can cause these failures independently or by mutually influencing each other, thereby leading to potentially critical traffic situations or even accidents. There is a need to analyse faults regarding their influence on the dynamic behaviour of road vehicles and to investigate their effect on the driver-vehicle interaction and to find new control strategies for fault handling.

    A structured method for the classification of faults regarding their influence on the longitudinal, lateral and yaw motion of a road vehicle is proposed. To evaluate this method, a broad failure mode and effect analysis was performed to identify and model relevant faults that have an effect on the vehicle dynamic behaviour. This fault classification method identifies the level of controllability, i.e. how easy or difficult it is for the driver and the vehicle control system to correct the disturbance on the vehicle behaviour caused by the fault.

    Fault-tolerant control strategies are suggested which can handle faults with a critical controllability level in order to maintain the directional stability of the vehicle. Based on the principle of control allocation, three fault-tolerant control strategies are proposed and have been evaluated in an electric vehicle with typical faults. It is shown that the control allocation strategies give a less critical trajectory deviation compared to an uncontrolled vehicle and a regular electronic stability control algorithm. An experimental validation confirmed the potential of this type of fault handling using one of the proposed control allocation strategies.

    Driver-vehicle interaction has been experimentally analysed during various failure conditions with typical faults of an electric driveline both at urban and motorway speeds. The driver reactions to the failure conditions were analysed and the extent to which the drivers could handle a fault were investigated. The drivers as such proved to be capable controllers by compensating for the occurring failures in time when they were prepared for the eventuality of a failure. Based on the experimental data, a failure-sensitive driver model has been developed and evaluated for different failure conditions. The suggested fault classification method was further verified with the conducted experimental studies.

    The interaction between drivers and a fault-tolerant control system with the occurrence of a fault that affects the vehicle dynamic stability was investigated further. The control allocation strategy has a positive influence on maintaining the intended path and the vehicle stability, and supports the driver by reducing the necessary corrective steering effort. This fault-tolerant control strategy has shown promising results and its potential for improving traffic safety.

  • 209.
    Wanner, Daniel
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Fordonsdynamik.
    Faults and their influence on the dynamic behaviour of electric vehicles2013Licentiatavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    The increase of electronics in road vehicles comes along with a broad variety of possibilitiesin terms of safety, handling and comfort for the users. A rising complexityof the vehicle subsystems and components accompanies this development and has tobe managed by increased electronic control. More potential elements, such as sensors,actuators or software codes, can cause a failure independently or by mutually influencingeach other. There is a need of a structured approach to sort the faults from avehicle dynamics stability perspective.This thesis tries to solve this issue by suggesting a fault classification method and faulttolerantcontrol strategies. Focus is on typical faults of the electric driveline and thecontrol system, however mechanical and hydraulic faults are also considered. Duringthe work, a broad failure mode and effect analysis has been performed and the faultshave been modeled and grouped based on the effect on the vehicle dynamic behaviour.A method is proposed and evaluated, where faults are categorized into different levelsof controllability, i. e. levels on how easy or difficult it is to control a fault for the driver,but also for a control system.Further, fault-tolerant control strategies are suggested that can handle a fault with acritical controllability level. Two strategies are proposed and evaluated based on thecontrol allocation method and an electric vehicle with typical faults. It is shown thatthe control allocation approaches give less critical trajectory deviation compared to noactive control and a regular Electronic Stability Control algorithm.To conclude, this thesis work contributes with a methodology to analyse and developfault-tolerant solutions for electric vehicles with improved traffic safety.

  • 210.
    Wanner, Daniel
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Fordonsdynamik.
    Drugge, Lars
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Fordonsdynamik.
    Edrén, Johannes
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Fordonsdynamik.
    Stensson Trigell, Annika
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Fordonsdynamik.
    Modelling and experimental evaluation of driver behaviour during single wheel hub motor failures2015Ingår i: Proceedings of the 3rd International Symposium on Future Active Safety Technology Towards zero traffic accidents (FASTzero'15), 2015Konferensbidrag (Refereegranskat)
    Abstract [en]

    A failure-sensitive driver model has been developed in the research study presented in this paper. The model is based on measurements of human responses to dierent failure conditions inuencing the vehicle directional stability in a moving-base driving simulator. The measurements were made in a previous experimental study where test subjects were exposed to three sudden failure conditions that required adequate corrective measures to maintain the vehicle control and regain the planned trajectory. A common driver model and a failure-sensitive driver model have been compared, and results for the latter agree well with the measured data. The proposed failure-sensitive driver model is capable of maintaining the vehicle control and regaining the planned trajectory similarly to the way in which humans achieved this during a wheel hub motor failure in one of the rear wheels.

  • 211.
    Wanner, Daniel
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Fordonsdynamik.
    Drugge, Lars
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Fordonsdynamik.
    Stensson Trigell, Annika
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Fordonsdynamik.
    Design and experimental evaluation of a fault-tolerant control strategy with and without a driver in the loopManuskript (preprint) (Övrigt vetenskapligt)
    Abstract [en]

    In this work, a fault-tolerant control strategy for an electric vehicle is developed and analysed for a wheel hub motor failure during a straight line driving manoeuvre. Based on the control allocation principle, an analytical approach is compared to an optimisation approach and both are investigated for their suitability to handle such failures. The analytical control allocation strategy has shown promising results similar to the optimal control allocation strategy. The improvements in vehicle stability and maintained desired path are also verified by experiments. The analytical approach is implemented in an experimental vehicle verifying the simulation results without driver in the loop. An experimental study including drivers is further conducted to analyse the influence of the control allocation strategy on the driver-vehicle interaction for the same manoeuvre. Further improvements for vehicle stability and lateral deviation are found for the driver study when an analytical control allocation strategy is included. The driver-vehicle interaction to a fault is improved strongly due to controller intervention. This fault-tolerant control strategy has shown promising results and its potential to improve traffic safety.

  • 212.
    Wanner, Daniel
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Fordonsdynamik.
    Drugge, Lars
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Fordonsdynamik.
    Stensson Trigell, Annika
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Fordonsdynamik.
    Fault classification method for the driving safety of electrified vehicles2014Ingår i: Vehicle System Dynamics, ISSN 0042-3114, E-ISSN 1744-5159, Vol. 52, nr 5, s. 704-732Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A fault classification method is proposed which has been applied to an electric vehicle. Potential faults in the different subsystems that can affect the vehicle directional stability were collected in a failure mode and effect analysis. Similar driveline faults were grouped together if they resembled each other with respect to their influence on the vehicle dynamic behaviour. The faults were physically modelled in a simulation environment before they were induced in a detailed vehicle model under normal driving conditions. A special focus was placed on faults in the driveline of electric vehicles employing in-wheel motors of the permanent magnet type. Several failures caused by mechanical and other faults were analysed as well. The fault classification method consists of a controllability ranking developed according to the functional safety standard ISO 26262. The controllability of a fault was determined with three parameters covering the influence of the longitudinal, lateral and yaw motion of the vehicle. The simulation results were analysed and the faults were classified according to their controllability using the proposed method. It was shown that the controllability decreased specifically with increasing lateral acceleration and increasing speed. The results for the electric driveline faults show that this trend cannot be generalised for all the faults, as the controllability deteriorated for some faults during manoeuvres with low lateral acceleration and low speed. The proposed method is generic and can be applied to various other types of road vehicles and faults.

  • 213.
    Wanner, Daniel
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Fordonsdynamik.
    Edrén, Johannes
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Fordonsdynamik.
    Jonasson, Mats
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Fordonsdynamik.
    Wallmark, Oskar
    KTH, Skolan för elektro- och systemteknik (EES), Elektrisk energiomvandling.
    Drugge, Lars
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Fordonsdynamik.
    Stensson Trigell, Annika
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Fordonsdynamik.
    Fault-Tolerant Control of Electric Vehicles with In-Wheel Motors through Tyre-Force Allocation2012Ingår i: Proceedings of the 11th International Symposium on Advanced Vehicle Control, Seoul: Japan Society of Mechanical Engineers (JSAE) , 2012Konferensbidrag (Refereegranskat)
    Abstract [en]

    This paper presents a fault handling strategy for electric vehicles with in-wheel motors. The ap-plied control algorithm is based on tyre-force allocation. One complex tyre-force allocation meth-od, which requires non-linear optimization, as well as a simpler tyre force allocation method are developed and applied. A comparison between them is conducted and evaluated against a standard reference vehicle with an Electronic Stability Control (ESC) algorithm. The faults in consideration are electrical faults that can arise in in-wheel motors of permanent-magnet type. The results show for both tyre-force allocation methods an improved re-allocation after a severe fault and thus re-sults in an improved state trajectory recovery. Thereby the proposed fault handling strategy be-comes an important component to improve system dependability and secure vehicle safety.

  • 214.
    Wanner, Daniel
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Fordonsdynamik.
    Kreußlein, Maria
    Department of Psychology, Technische Universitat Chemnitz, Chemnitz, Germany.
    Augusto, Bruno
    VTI Swedish National Road and Transport Research Institute, Gothenburg, Sweden.
    Drugge, Lars
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg.
    Stensson Trigell, Annika
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Fordonsdynamik.
    Single wheel hub motor failures and their impact on vehicle and driver behaviourManuskript (preprint) (Övrigt vetenskapligt)
    Abstract [en]

    This research work studies the impact of single wheel hub motor failures on the dynamic behaviour of electric vehicles and the corresponding driver reactions. An experimental study in a moving-base driving simulator is conducted to analyse the inuence of single wheel hub motor failures for motorway speeds. Driver reaction times are derived from the measured data and discussed in their experimental context. The failure is rated objectively on the dynamic behaviour of the vehicle and compared to the subjective evaluation. Findings indicate that critical trac situations impairing trac safety can occur for motorway speeds. Clear counteractions by the drivers had to be taken.

  • 215.
    Wanner, Daniel
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Fordonsdynamik.
    Neumann, Isabel
    Department of Psychology, Technische Universitat Chemnitz, Chemnitz, Germany.
    Drugge, Lars
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Fordonsdynamik.
    Cocron, Peter
    Department of Psychology, Technische Universitat Chemnitz, Chemnitz, Germany.
    Bierbach, Maxim
    Active Vehicle Safety, Emissions and Energy, Federal Highway Research Institute (BASt), Bergisch Gladbach, Germany.
    Stensson Trigell, Annika
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Fordonsdynamik.
    Experimental study on single wheel hub motor failures and their impact on the driver-vehicle behavior2016Ingår i: Proceedings of the ASME 2015 International Design Engineering Technical Conferences & Computers and Information in Engineering Conference IDETC/CIE 2015, Boston, USA: ASME Press, 2016, artikel-id UNSP V003T01A001Konferensbidrag (Refereegranskat)
    Abstract [en]

    An experimental field study investigating the impact of single wheel hub motor failures on the dynamic behavior of a vehicle and the corresponding driver reaction is presented in this work. The experiment is performed at urban speeds on a closed off test track. The single wheel hub motor failure is emulated with an auxiliary brake system in a modified electric vehicle. Driver reaction times are derived from the measured data and discussed in their experimental context. The failure is rated and evaluated objectively based on the dynamic behavior of the vehicle. Findings indicate that driver reactions are more apparent for the accelerator pedal compared to the steering wheel response. The controllability evaluation of the vehicle behavior shows that no critical traffic situation occurs for the tested failure conditions. However, even small deviations of the vehicle can impair traffic safety, specifically for other traffic participants like bicyclist and pedestrians.

  • 216.
    Wanner, Daniel
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Fordonsdynamik.
    Stensson Trigell, Annika
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Fordonsdynamik.
    Drugge, Lars
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Fordonsdynamik.
    Jerrelind, Jenny
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Fordonsdynamik.
    Survey on fault-tolerant vehicle design2012Konferensbidrag (Refereegranskat)
    Abstract [en]

    Fault-tolerant vehicle design is an emerging inter-disciplinary research domain, which is of increasedimportance due to the electrification of automotive systems. The goal of fault-tolerant systems is to handleoccuring faults under operational condition and enable the driver to get to a safe stop. This paperpresents results from an extended survey on fault-tolerant vehicle design. It aims to provide a holisticview on the fault-tolerant aspects of a vehicular system. An overview of fault-tolerant systems in generaland their design premises is given as well as the specific aspects related to automotive applications. Thepaper highlights recent and prospective development of vehicle motion control with integrated chassiscontrol and passive and active fault-tolerant control. Also, fault detection and diagnosis methods arebriefly described. The shift on control level of vehicles will be accompanied by basic structural changeswithin the network architecture. Control architecture as well as communication protocols and topologiesare adapted to comply with the electrified automotive systems. Finally, the role of regulations andinternational standardization to enable fault-tolerant vehicle design is taken into consideration.

  • 217.
    Wanner, Daniel
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Fordonsdynamik.
    Wallmark, Oskar
    KTH, Skolan för elektro- och systemteknik (EES), Elektrisk energiomvandling.
    Jonasson, Mats
    Volvo Cars AB.
    Drugge, Lars
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Fordonsdynamik.
    Stensson Trigell, Annika
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Fordonsdynamik.
    Control allocation strategies for an electric vehicle with a wheel hub motor failure2015Ingår i: International Journal of Vehicle Systems Modelling and Testing, ISSN 1745-6436, Vol. 10, nr 3, s. 263-287Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Three fault-tolerant control strategies for electric vehicles with wheel hub motors are presented and compared, which are all based on the control allocation principle. The main objective is to maintain the directional stability of the vehicle in case of a component failure during high speed manoeuvres. Two simplified strategies that are suited for on-board implementation are derived and compared to an optimal control allocation strategy and a reference vehicle with a basic electronic stability control system. The occurring faults are considered to be in the electric high-voltage system that can arise in wheel hub motors. All three control allocation strategies show improved re-allocation of traction forces after a severe fault, and hence an improved directional stability. However, the performance of both simplified algorithms shows limitations in case of force demands outside the capabilities of the respective actuator. This work shows that vehicle safety is increased by the proposed fault-tolerant control strategies.

  • 218.
    Wei, Cheng
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Fordonsdynamik.
    Air Induction System (AIS) Optimization2016Självständigt arbete på avancerad nivå (masterexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [en]

    Air intake system (AIS) plays an important role on affecting the performance of the engine and the vehicle. The design and optimization of the structures and materials of AIS contributes to producing a quality reliable system, reducing noise, cost and weight at the same time, which are significant to improve the performance of engine and vehicle. Fresh air hoses/pipes are intended to transport, in air cleaner purified, air from the air cleaner to the throttle fitted on the inlet manifold or to the compressor fitted to the exhaust manifold. Air cleaner box is responsible for filtering out the dust and impurities in the air. The charge air pipes are intended to transport purified compressed air from the compressor to the charge air cooler and then to the throttle fitted on the inlet pipe.

    For the air cleaner box optimization, through the benchmarking and the innovation ideas from the daily life, two alternative optimized designs were introduced to reduce the cost and weight. The first is four clips connectors and the other is spring clamps. For the hose clamps, another innovation design was introduced to replace the previous hose clamps, which is called friction connector on the inner side of the bellow hose, the outer side of the air cleaner box lid and the clean side duct. For the material of the charge air ducts, TPEE was selected to replace the previous EACM rubber hoses. Further tests and prototypes should be conducted and produced to verify the effect of the optimization.

  • 219.
    Wilcox, Bryan
    et al.
    University of Illinois at Urbana-Champaign, Department of Mechanical Science and Engineering, Illinois, USA.
    Svahn, Fredrik
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Fordonsdynamik.
    Dankowicz, Harry
    University of Illinois at Urbana-Champaign, Department of Mechanical Science and Engineering, Illinois, USA.
    Jerrelind, Jenny
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Fordonsdynamik.
    Transient growth rates of near-grazing impact velocities: Theory and experiments2009Ingår i: Journal of Sound and Vibration, ISSN 0022-460X, E-ISSN 1095-8568, Vol. 325, nr 4-5, s. 950-958Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In this paper, nonsmooth fold bifurcations associated with the onset of low-relative- velocity (near-grazing) impacts in an oscillatory mechanical system are proposed as a potential operating principle for high-speed limit switches. Specifically, analytical, numerical, and experimental methods are employed to investigate the near-grazing transient behavior in a representative system. It is shown that the rate of growth of successive impact velocities increases beyond all bounds as the threshold parameter value is approached. A limit switch based on the proposed nonsmooth fold scenario would thus be expected to outperform one that relies on a smooth bifurcation, such as the cyclic-fold bifurcation, in terms of switching speed and sensitivity.

  • 220. Yang, D.
    et al.
    Jacobson, B.
    Jonasson, Mats
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Fordonsdynamik.
    Gordon, T. J.
    Minimizing Vehicle Post Impact Path Lateral Deviation Using Optimized Braking And Steering Sequences2014Ingår i: International Journal of Automotive Technology, ISSN 1229-9138, E-ISSN 1976-3832, Vol. 15, nr 1, s. 7-17Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This paper investigates the optimal control of a vehicle, after a light impact during a traffic accident. To reduce the risk of secondary events, the control target is set: to minimize the maximum lateral deviation from the initial path. In previous analysis path control was achieved by the active control of individual wheel braking. The present paper examines potential benefits from the additional control of front steering angles. Numerical optimization is used to determine optimal control sequences for both actuator configurations. It is found that steering provides significant control benefits, though not for all post-impact kinematics. For all cases considered, the optimal control operates at the boundary of the control domain of available forces and moments. This domain is expanded when steering is available, and there exists an expanded range of conditions for which coupled control of yaw moments and lateral forces is the most effective control strategy. The sensitivity of vehicle response to the individual actuator controls is studied; it reveals this sensitivity is related to the actuator bandwidth and the lack of any dynamic cost in the longitudinal direction. This motivates a further analysis which includes longitudinal and lateral dynamics in the cost function. This is broadly related to real-world crash risks. Further, different versions of such cost functions are compared as a basis for implementation in a closed-loop controller.

  • 221. Yang, D.
    et al.
    Jonasson, Mats
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Fordonsdynamik. Volvo Cars, Sweden.
    Halleröd, T.
    Johansson, R.
    Evaluation of an evasive manoeuvre assistance system at imminent side collisions2017Ingår i: Advanced Vehicle Control AVEC’16 - Proceedings of the 13th International Symposium on Advanced Vehicle Control AVEC’16, CRC Press/Balkema , 2017, s. 55-60Konferensbidrag (Refereegranskat)
    Abstract [en]

    In this paper, the performance of an Evasive Manoeuvre Assistance System is evaluated on the test track, where an imminent half-overlapping side collision scenario is reconstructed. The control function here aims to reduce the steering effort for an emergency swerve in front of obstacle and to ease the following recovery into the driver perceived safe zone. This is realized by combined differential braking and steering torque overlay, which improves the agreement between steering input and vehicle response. Preliminary test results have shown that the function has a great potential to reduce collision risk at the presence of suddenly appeared obstacle in front.

  • 222. Yoshimura, Kimiyasu
    et al.
    Davari, Mohammad Mehdi
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Fordonsdynamik. KTH, Skolan för teknikvetenskap (SCI), Centra, VinnExcellence Center for ECO2 Vehicle design.
    Drugge, Lars
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Fordonsdynamik. KTH, Skolan för teknikvetenskap (SCI), Centra, VinnExcellence Center for ECO2 Vehicle design.
    Jerrelind, Jenny
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Fordonsdynamik. KTH, Skolan för teknikvetenskap (SCI), Centra, VinnExcellence Center for ECO2 Vehicle design.
    Stensson Trigell, Annika
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Fordonsdynamik. KTH, Skolan för teknikvetenskap (SCI), Centra, VinnExcellence Center for ECO2 Vehicle design.
    Studying Road Roughness Effect on Rolling Resistance Using Brush Tyre Model and Self-Affine Fractal Surfaces2016Ingår i: The Dynamics of Vehicles on Roads and Tracks - Proceedings of the 24th Symposium of the International Association for Vehicle System Dynamics, IAVSD 2015, CRC Press, 2016, s. 273-280Konferensbidrag (Refereegranskat)
    Abstract [en]

    While there are many tyre and vehicle dependent factors that affect the rollingresistance, the road properties play also an influential role in the overall resistance on the vehicle.The aim of this study is to develop amodel that can estimate the effect of road roughness on rollingresistance of tyres where both the texture-dependent and independent factors are contributing tooverall rolling resistance. In this paper, a method based on the self-affine fractal surfaces is usedto model realistic road characteristics in order to couple it with a brush based tyre model to beable to study the influence of road roughness on tyre rolling resistance. The simulation resultssuggest that the rolling resistance increases with increased RMS-value and both the macro- andthe micro-texture have an influence on the rolling resistance while the macro-texture effect is moreinfluential. The results of this paper can be related to the estimation of fuel economy on differentroad textures, from macro-texture to micro-texture and further optimisation of road surfaces.

  • 223.
    Zetterberg Wallin, Georg
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Fordonsdynamik.
    Crétier, Matthieu
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Fordonsdynamik.
    A supervised learning approach to estimate the drivers impact on fuel consumption: A heavy-duty vehicle case study2016Självständigt arbete på avancerad nivå (masterexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [en]

    The aim of this Master thesis is to provide a statistical analysis of the factors inuencing the fuel consumption, with a focus on the separation of the drivers' performance. The study is focused on the long haulage trucks, which correspond to the application where the fuel consumption becomes of primary interest from the economical point of view. Further developments of the work leads to a graphical representation of the outcomes on a map, highlighting in particular the segments of the road network having the highest variation of the driver-inuenced fuel consumption. The analysis dataset created is the combination of data coming from di erent sources and additional features computed based on them. The datasources are providing respectively the vehicles' operating data and congurations, the road network's characteristics and the weather information. The results obtained prove that it is possible to isolate the driver factor from the overall fuel consumption. This can be achieved by training a model composed by variables statistically chosen through a regression procedure. Further in the analysis the di erent driver factors are used in order to determine the fuel saving potential of the road stretches where the factors are computed. The results are gathered in multiple stages, based on the dimension of the dataset considered and the method used. Two methods are used to train the model: the least squares regression and the ridge regression. First the whole Swedish road network composed by primary roads is analyzed with least squares. 1195 road stretches belonging to this network present a dened and di erent than zero fuel saving potential varying between 0.003 and 83.71 l/100km. Then, a smaller portion of the same road network is analyzed after being provided with road slope information. The fuel saving potential estimated using ridge regression present values between 0.002 and 24.39 l/100km.

    From the geographical point of view little can be deduced from the analysis of the complete network. The E4 provided with slope data, on the contrary, allows a better insight, especially using ridge.

  • 224.
    Zhang, Wenliang
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg. National Engineering Laboratory for Electric Vehicles and the Collaborative Innovation Centre for Electric Vehicles in Beijing.
    Wang, Zhenpo
    School of Mechnical Engineering, Beijing Institute of Technology.
    Zou, Changfu
    Department of Electrical Engineering, Chalmers University of Technology.
    Drugge, Lars
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Fordonsdynamik.
    Nybacka, Mikael
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Fordonsdynamik.
    Advanced Vehicle State Monitoring:: Evaluating Moving Horizon Estimators and Unscented Kalman Filter2019Ingår i: IEEE Transactions on Vehicular Technology, ISSN 0018-9545, E-ISSN 1939-9359, Vol. 68, nr 6, s. 5430-5442, artikel-id 8682143Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Active safety systems must be used to manipulate the dynamics of autonomous vehicles to ensure safety. To this end, accurate vehicle information, such as the longitudinal and lateral velocities, is crucial. Measuring these states, however, can be expensive, and the measurements can be polluted by noise. The available solutions often resort to Bayesian filters such as the Kalman filter, but can be vulnerable and erroneous when the underlying assumptions do not hold. With its clear merits in handling nonlinearities and uncertainties, moving horizon estimation (MHE) can potentially solve the problem and is thus studied for vehicle state estimation. This paper designs an unscented Kalman filter, standard MHE, modified MHE and recursive least squares MHE to estimate critical vehicle states, respectively. All the estimators are formulated based upon a highly nonlinear vehicle model that is shown to be locally observable. The convergence rate, accuracy and robustness of the four estimation algorithms are comprehensively characterised and compared under three different driving manoeuvres. For MHE-based algorithms, the effects of horizon length and optimisation techniques on the computational efficiency and accuracy are also investigated.

  • 225.
    Öhnander, Fred
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Fordonsdynamik.
    Höghastighetståg på rätt spår?: EN HISTORISK OCH TEKNISK ANALYS AV HÖGHASTIGHETSTÅG I VÄRLDEN2015Självständigt arbete på grundnivå (kandidatexamen), 10 poäng / 15 hpStudentuppsats (Examensarbete)
    Abstract [sv]

    Det finns en stor efterfrågan på ökad mobilitet och effektivitet för höghastighetståg i världen. Resenärer vill så snabbt och smidigt som möjligt anlända till sina destinationer. För att uppfylla dessa krav krävs en förbättring av restiderna mellan järnvägsstationer. Detta kan åtgärdas genom en ökning av hastigheter på höghastighetslinjer och mer specifikt behöver medelhastigheten mellan stationer ökas.

    Det är därför intressant att utforska hur denna utveckling av högre hastigheter har utvecklats ur ett historiskt perspektiv. Målsättningen är även att öka förståelsen för ett antal tekniska områden och innovationer som har inverkan på ett tågs medelhastighet. Rent konkret behandlas korglutning, aerodynamik och virvelströmsbroms, som alla har en viktig inverkan på medelhastigheten.

    Arbetet grundar sig främst på litteraturstudier av redan kända kunskaper ur ett teknikhänseende. Information om historisk utveckling i olika länder har erhållits främst från internetkällor och där förståelse för tekniska lösningar till höghastighetståg behövts har forskningsrapporter, artiklar och doktorsavhandlingar studerats.

    Användning av korglutningssystem är lämpligt för tåg som trafikerar äldre järnvägslinjer där många horisontalkurvor finns. Passiv korglutningsteknik fungerar effektivt vad gäller att reducera sidoaccelerationer. Dock försämras säkerheten eftersom tyngdpunkten för tåget förskjuts i sidled. Den aktiva korglutningstekniken kompenserar för sidoaccelerationen och tyngdpunkten förskjuts marginellt. En hastighetsökning på cirka 15% och en restidsvinst på cirka 10% erhålls för ett tåg med aktiv korglutningsteknik.

    Underliggande komponenter hos ett tåg har stor inverkan på det aerodynamiska motståndet om vagnskorgens motståndsarea är relativt stor. Tågets ytbeskaffenheter har stor inverkan på det aerodynamiska motståndet då vagnskorgens motståndsarea är relativt liten. Längden på en tågnos har liten inverkan på det aerodynamiska motståndet om ett längd/bredd-förhållande på minst 1,0 används. En lång och spetsig akter är optimal för att reducera motståndet.

    Virvelströmsbromsen är effektiv i höga hastigheter men bör kompletteras med andra bromssystem vid låg- och medelhöga hastigheter. Bromsen är slitagefri och oberoende av väderlek. På grund av stor värmeutveckling kan dock solkurvor uppkomma i spåren vid använding av bromsen.

2345 201 - 225 av 225
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