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  • 1.
    Bhat, Sriharsha
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Fordonsdynamik.
    Davari, Mohammad Mehdi
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Fordonsdynamik. KTH, Skolan för teknikvetenskap (SCI), Centra, VinnExcellence Center for ECO2 Vehicle design.
    Nybacka, Mikael
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Fordonsdynamik. KTH, Skolan för industriell teknik och management (ITM), Centra, Integrated Transport Research Lab, ITRL.
    Study on energy loss due to cornering resistance in over-actuated electric vehicles using optimal control2017Ingår i: SAE International Journal of Vehicle Dynamics, Stability, and NVH - V126-10, 2017Konferensbidrag (Refereegranskat)
    Abstract [en]

    As vehicles become electrified and more intelligent in terms of sensing, actuation and processing; a number of interesting possibilities arise in controlling vehicle dynamics and driving behavior. Over-actuation with in- wheel motors, all wheel steering and active camber is one such possibility, which facilitate the control strategies that push boundaries in energy consumption and safety. Optimal control can be used to investigate the best combinations of control inputs to an over-actuated system. This paper shows how an optimal control problem can be formulated and solved for an over-actuated vehicle case, and highlights the translation of this optimal solution to a real-world scenario, enabling intelligent means to improve vehicle efficiency. This paper gives an insight into the Dynamic Programming (DP) as an offline optimal control method that guarantees the global optimum. Therefore the optimal control allocation to minimize an objective function and simultaneously fulfill the defined constraints can be achieved. As a case study the effect of over-actuation on the cornering resistance were investigated in two different maneuvers i.e. step steer and sine with dwell, where in both cases the vehicle assumes to be in steady state situation. In this work the cornering resistance is the main objective function and maintaining the reference trajectory is the constraint which should be fulfilled. A parameter study is conducted on the benefits of over-actuation, and depending on the type of over-actuation about 15% and 50% reduction in cornering resistance were observed during step steer and sine with dwell maneuver respectively. From a second parameter study that focused on COG position from a safety perspective, it is more beneficial for the vehicle to be designed to under-steer than over-steer. Finally, a method is described to translate the offline optimal results to vehicle implementable controllers in the form of both feed-through lookup-tables and rule-based feed-forward control.

  • 2.
    Davari, Mohammad Mehdi
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Fordonsdynamik. KTH, Skolan för teknikvetenskap (SCI), Centra, VinnExcellence Center for ECO2 Vehicle design.
    A tyre model for energy studies in vehicle dynamics simulations2015Licentiatavhandling, sammanläggning (Övrigt vetenskapligt)
  • 3.
    Davari, Mohammad Mehdi
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Fordonsdynamik.
    Exploiting over-actuation to reduce tyre energy losses in vehicle manoeuvres2017Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    Due to environmental and economic challenges road vehicles need bettersolutions to reduce energy consumption. Improvement in tyre rolling e-ciency is one of the key enablers for lower energy consumption. The shifttowards electrication and intelligent driving creates new opportunities todevelop energy-ecient vehicles. For instant over-actuated vehicles whichenables dierent objectives such as safety, performance and energy e-ciency to be fullled during a manoeuvre. The objective of this thesis is todevelop a simulation environment to simulate the energy dissipated fromthe tyre in order to investigate the potential to controlling dierent chassisparameters to reduce rolling losses during driving.The rst part of the thesis is dedicated to develop a high-delity semi-physical non-linear tyre model called the Extended Brush Tyre Model(EBM) to be used for energy studies in vehicle dynamics simulations andlater answer whether it is reasonable to believe that there is any potentialto reduce the rolling loss, and thereby energy consumption, using over-actuation.In the second part of the thesis the benets of over-actuation are invest-igated to enable rolling loss reduction. A control strategy using camber-sideslip control (CSC) is proposed. The allocation problem is solved in the formof an optimisation problem using Dynamics Programming (DP) and ModelPredictive Control (MPC). Exploiting the function for a chosen vehicle ina simulation environment shows a signicant improvement of about 60% inrolling loss reduction while maintaining path tracking. Also by using thisfunction the tyre forces can be distributed more evenly while maintainingthe global force, which results in an increase in the available tyre forcesthat is especially benecial when driving at the limit. It is revealed thatoptimising the vehicle manoeuvre from an energy perspective is sometimesin con ict with the safety demand, thus the energy and safety criteria needto be considered simultaneously during optimisation.Finally, experimental studies using an over-actuated concept vehicleconrmed that the CSC function can reduce overall energy consumptionduring low velocity manoeuvres up to about 13%. By increasing the speed,the saving potential decreases but the contribution is nonetheless of signi-cance. The developed simulation environment, including the EBM, willenable future studies of dierent solutions using over-actuation to reducerolling losses in dierent types of vehicles and driving tasks.

  • 4.
    Davari, Mohammad Mehdi
    et al.
    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.
    Stensson Trigell, Annika
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Fordonsdynamik.
    Drugge, Lars
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Fordonsdynamik.
    A Multi-Line Brush Based Tyre Model to Study the Rolling Resistance and Energy Loss2015Ingår i: Proceedings of 4th International Tyre Colloquium: Tyre Models for Vehicle Dynamics Analysis, Guildford, UK (2015), 2015Konferensbidrag (Refereegranskat)
    Abstract [en]

    This study aim to develop a three dimensional multi-line brush based tyre model for investigating the rolling resistance and energy loss in tyres. The losses in the model are characterised by the external losses originated from the sliding phenomenon in the tyre contact patch, and the internal losses due to the tyre viscoelastic nature which is employed by a rubber model. The Extended Brush tyre Model (EBM) proposed in this work can be used to estimate the dissipated energy and the rolling resistance under different driving manoeuvres and wheel conditions. This paper focuses on the estimation of energy loss and in-plane rolling resistance.

  • 5.
    Davari, Mohammad Mehdi
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Centra, VinnExcellence Center for ECO2 Vehicle design. KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg.
    Jerrelind, Jenny
    KTH, Skolan för teknikvetenskap (SCI), Centra, VinnExcellence Center for ECO2 Vehicle design. KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg.
    Stensson Trigell, Annika
    KTH, Skolan för teknikvetenskap (SCI), Centra, VinnExcellence Center for ECO2 Vehicle design. KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg.
    Drugge, Lars
    KTH, Skolan för teknikvetenskap (SCI), Centra, VinnExcellence Center for ECO2 Vehicle design. KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg.
    Extended Brush Tyre Model to Study Rolling Loss in Vehicle Dynamics Simulations2017Ingår i: International Journal of Vehicle Design, ISSN 0143-3369, E-ISSN 1741-5314, Vol. 73, nr 4, s. 255-280Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This paper describes a semi-physical tyre model that enables studies of rolling loss in combination with vehicle dynamic simulations. The proposed model, named extended brush tyre model (EBM), takes the effects of driving conditions, wheel alignment, and tyre materials into account. Compared to the basic brush tyre model, EBM includes multiple numbers of lines and bristles as well as integrated rubber elements into the bristles. The force and moment characteristics of the model are shown to have a good correlation with the Magic Formula tyre model and experimental data. The numerically estimated rolling resistance coefficients under different conditions are compared to findings in the literature, FE-simulations and experiments. The model can capture some aspects that are not covered by the available literature and experimental observations such as camber effect on rolling loss. EBM can be used as a platform for future studies of rolling loss optimisation using active chassis control.

  • 6.
    Davari, Mohammad Mehdi
    et al.
    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.
    Stensson Trigell, Annika
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Fordonsdynamik.
    Edrén, Johannes
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Fordonsdynamik.
    Investigating the Potential of Wheel Corner Modules in Reducing Rolling Resistance of Tyres2014Ingår i: Proceedings of FISITA "14 World Automotive Congress, Maastricht, Netherlands (2014), 2014Konferensbidrag (Refereegranskat)
    Abstract [en]

    The improvement in tire rolling efficiency is one of the key elements to optimize the fuel economy and thereby reduce the vehicle emissions. Earlier efforts to reduce the rolling resistance have mainly been focusing on new materials in the tire compounds. The overall research aim of this study is to present the potentials ofimplementing innovative chassis concepts with the focus on Wheel Corner Modules (WCM) by describing thepossibilities in affecting rolling resistance and relating them to previous research findings. The core idea of theconcept is to actively control and actuate all degrees of freedom in the wheel i.e. implementing steering,suspension and propulsion functions into a unique module which can be implemented in each corner of the vehicle. Using this concept the limitations of traditional wheel kinematics can be resolved extensively. This article presents the first step towards creating a vehicle simulation model that can show how the WCM functionality can influence the rolling resistance. A model of loss is chosen after analysing the behaviour of three different rubber models and then implemented into a brush tire model. An effective way, but less complicatedcompared to current methods, to introduce the loss into tire model is presented. In conventional suspensions, thedesign is compromising between for example safety, comfort and rolling resistance, etc. at all drivingconditions. However, using the WCM, the possibility of achieving a better compromise between those objectivesis possible. Finally, based on WCM functionalities a plausible control architecture is proposed.

  • 7.
    Davari, Mohammad Mehdi
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Fordonsdynamik.
    Jonasson, Mats
    KTH.
    Drugge, Lars
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg.
    Jerrelind, Jenny
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg.
    Stensson Trigell, Annika
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg.
    Rolling Loss Optimisation of an Over-actuated Vehicle using Predictive Control of Steering and Camber ActuatorsArtikel i tidskrift (Refereegranskat)
  • 8.
    Davari, Mohammad Mehdi
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Fordonsdynamik.
    Jonasson, Mats
    KTH.
    Jerrelind, Jenny
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg.
    Stensson Trigell, Annika
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg.
    An Energy Oriented Control Allocation Strategy for Over-actuated Road VehiclesArtikel i tidskrift (Refereegranskat)
  • 9.
    Davari, Mohammad Mehdi
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Fordonsdynamik.
    Jonasson, Mats
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Fordonsdynamik.
    Jerrelind, Jenny
    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.
    Rolling loss analysis of combined camber and slip angle control2016Konferensbidrag (Refereegranskat)
    Abstract [en]

    The objective of this work is to present a new functionality of over-actuated systems, such as Wheel Corner Modules, to reduce the rolling loss in vehicles. The findings are based on numerical simulations using a bicycle model coupled with a newly proposed tyre model which is capable of simulating the tyre losses during vehicle motions. The results show that for the considered vehicle in the considered manoeuvre the rolling loss can be reduced about 25–40% by proper control of camber and slip angle combinations, while still maintaining the vehicle performance.

  • 10.
    Davari, Mohammad Mehdi
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Fordonsdynamik.
    Jerrelind, Jenny
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg.
    Stensson Trigell, Annika
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg.
    Energy Efficiency Analyses of a Vehicle in Modal and Transient Driving Cycles including Longitudinal and Vertical Dynamics2017Ingår i: Transportation Research Part D: Transport and Environment, ISSN 1361-9209, E-ISSN 1879-2340, Vol. 53, s. 263-275Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The growing concerns about the environmental issues caused by vehicles and a strive forbetter fuel economy, urge the legislators to introduce conservative regulations on vehicletesting and homologation procedures. To have accurate evaluations, driving cycles thatcan sufficiently describe the vehicles’ conditions experienced during driving is a prerequisite.In current driving cycles there are still some issues which are disregarded. The aim ofthe presented work is to study the contribution of chassis and vehicle dynamics settings ontyre rolling loss in comparison with the original assumptions made in the NEDC, FTP andHWFET driving cycles. A half-car model including a semi-physical explicit tyre model tosimulate the rolling loss is proposed. For the chosen vehicle and tyre characteristics,depending on the specific chassis settings and considered driving cycle, considerable differenceup to 7% was observed between the energy consumption of the proposed- and conventionalapproach. The current work aims to provide the legislators with a betterinsight into the real effects of chassis and vehicle dynamics during the certification processto further improve the test related procedures required for homologation such as generationof road load curves. I.e., the aim is not to provide a new homologation process, sincethere are also other effects such as road roughness and tyre temperature that need to beconsidered. The results are also of interest for the vehicle manufacturers for further considerationsduring test preparation as well as in the development phase in order to reduce theenvironmental impacts.

  • 11.
    Jerrelind, Jenny
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Fordonsdynamik.
    Edrén, Johannes
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Fordonsdynamik.
    Li, Shiruo
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Fordonsdynamik.
    Davari, Mohammad Mehdi
    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.
    Exploring active camber to enhance vehicle performance and safety2013Konferensbidrag (Refereegranskat)
    Abstract [en]

    The aim of this study is to evaluate optimal active camber strategies for improvement of vehicle performance and safety during limit handling. Numerical optimisation is used to find solutions on how the active camber should be controlled and coordinated in cooperation with individual braking and front axle steering. Based on the characteristics of a multi-line brush tyre model, a Simple Magic Formula description is developed where camber dependency, load sensitivity and first order speed dependent relaxation dynamics are included. The vehicle is analysed during an evasive manoeuvre when the vehicle is running at the limit. It is evident from the results that active camber control can improve safety and performance during an avoidance manoeuvre.

  • 12. 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.

1 - 12 av 12
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  • rtf