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  • 1.
    Agebro, Markus
    et al.
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering.
    Nilsson, Andreas
    Stensson Trigell, Annika
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Vehicle Dynamics.
    Driver preferences of steering gear ratio and steering wheel effort: A driving simulator study2006In: Proceedings of the FISITA World Automotive Congress, Yokohama, Japan 2006., 2006Conference paper (Refereed)
    Abstract [en]

    When driving an automobile, the driver has to correct the course as a result of road curvature and external disturbances. In order to make the vehicle both controllable and comfortable to drive, it is important that the steering system is designed with different drivers in mind. In this work, driver preferences of steering system characteristics is investigated by comparing standard steering wheel settings with unconventional steering gear ratio and steering wheel effort. The investigation is made using 18 test subjects in a moving base driving simulator. The evaluation includes two scenarios. In the first scenario the driver is overtaking a bus at 110 km/h when meeting traffic in the opposite lane. In the second scenario the driver is doing a manoeuvre by following a cone track at 55 km/h. To investigate if there are differences in preference of drivers with varying experience of driving, the drivers are chosen to either be low or high mileage drivers. People that drive less than 5,000 km/year are considered to be low mileage drivers, and people that drive more than 25,000 km/year are considered to be high mileage drivers.

    The results show that original settings of a typical passenger car, which served as reference, prove to display favourable characteristics compared to the unconventional settings investigated. However, there might be settings within the investigated intervals that can be considered superior. A distinct trend in the results is that increasing effort will lead to increased perceived stability, independent of ratio. High mileage drivers find the setting with low ratio and reference effort to possess better qualities than the reference when evaluating the attributes steering wheel force and response and only slightly less favourable properties than the reference when evaluating the attribute stability. High mileage drivers display a more distinct opinion and a higher sensitivity when evaluating the attributes. Despite the differing setup of the scenarios, many similarities can be observed when studying the results. Even though there are similarities in the results both between the scenarios and the categories of drivers, a study of the individual test subjects´ preferences reveal that several drivers prefer other settings than the reference for the investigated scenarios. Therefore, it is clear that the driver-vehicle system would benefit from tailoring the steering characteristics to the situation and driver.

  • 2.
    Berg, Mats
    et al.
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Rail Vehicles.
    Stensson Trigell, AnnikaKTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Vehicle Dynamics.
    Selected and extended papers from the 21st symposium of the International Association of Vehicle System Dynamics: held at the Royal Institute of Technology (KTH), Stockholm, Sweden, August 17-21, 20092010Conference proceedings (editor) (Refereed)
  • 3.
    Berg, Mats
    et al.
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Rail Vehicles.
    Stensson Trigell, AnnikaKTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Vehicle Dynamics.
    Special Issue: State of the Art Papers of the 21st IAVSD Symposium2009Conference proceedings (editor) (Refereed)
  • 4. Berghuvud, A.
    et al.
    Stensson, Annika
    Consequences of nonlinear characteristics of a secondary suspension in a three-piece freight car bogieIn: Vehicle System Dynamics, ISSN 0042-3114, p. 37-55Article in journal (Refereed)
    Abstract [en]

    Mechanical systems with nonlinear characteristics can show a complex dynamic behavior that should be taken into account when analysing dynamic performance and reliability. The dynamic behavior of the main suspension in a three-piece freight car bogie with constant friction damping is considered in this work. The aim is to investigate the vertical behavior of a specific suspension design due to different driving conditions, weather and wear of the friction wedges. A variation in weather and wear is represented by different friction configurations in the model of the suspension. Models of different levels of detail that are based on experimental data on existing designs are developed. It is found that the suspension performance is very sensitive to variations of the friction configuration and this indicates a possible presence of nonlinear dynamic phenomena at in service like conditions.

  • 5. Dahlberg, E.
    et al.
    Stensson, Annika
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Vehicle Dynamics.
    The dynamic rollover threshold - a heavy truck sensitivity study2006In: International Journal of Vehicle Design, ISSN 0143-3369, E-ISSN 1741-5314, Vol. 40, no 03-jan, p. 228-250Article in journal (Refereed)
    Abstract [en]

    Knowledge of rollover mechanics, which is required in heavy truck development, commonly relies on a static analysis, providing the steady-state rollover threshold, SSRT. In a rolling vehicle, kinetic energy is always present and that deteriorates the analysis of roll stability from SSRT and implies the need for a dynamic rollover threshold, DRT as a complement. A method to determine DRT is presented and a parameter sensitivity study The influences on SSRT and DRT, including interaction effects, from roll stiffnesses and roll centre heights, are calculated. Results show that a rigid truck and a tractor semitrailer combination are unequally sensitive to parameter changes. Design changes can hence affect SSRT and DRT differently, which indicates that two vehicles can be equally stable statically but differently dynamically. Therefore, if DRT is not analysed, a redesign of a vehicle can deteriorate roll stability even though it appears to improve it.

  • 6.
    Daniel, Wanner
    et al.
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Vehicle Dynamics.
    Nybacka, Mikael
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Vehicle Dynamics.
    Wallmark, Oskar
    KTH, School of Electrical Engineering (EES), Electrical Energy Conversion.
    Drugge, Lars
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Vehicle Dynamics.
    Stensson Trigell, Annika
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Vehicle Dynamics.
    Experimental implementation of a fault handling strategy for electric vehicles with individual-wheel drives2016In: 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, p. 147-152Conference paper (Refereed)
    Abstract [en]

    This paper presents a fault handling strategy for electric vehicles with four individual-wheel drives, which are based on wheel hub motors. The control strategy to handle the faults is based on the principle of control allocation and is implemented in an experimental vehicle. Experimental tests has been performed with the experimental vehicle and with simulation. The results show that the directional stability of such a vehicle can be improved for the analysed manoeuvre and failure mode, and the tendencies of the experimental results correspond with the simulation results. It has been found that the lateral and yaw motion could be strongly improved. 

  • 7.
    Davari, Mohammad Mehdi
    et al.
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Vehicle Dynamics.
    Jerrelind, Jenny
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering.
    Stensson Trigell, Annika
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering.
    Energy Efficiency Analyses of a Vehicle in Modal and Transient Driving Cycles including Longitudinal and Vertical Dynamics2017In: Transportation Research Part D: Transport and Environment, ISSN 1361-9209, E-ISSN 1879-2340, Vol. 53, p. 263-275Article in journal (Refereed)
    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.

  • 8.
    Davari, Mohammad Mehdi
    et al.
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Vehicle Dynamics. KTH, School of Engineering Sciences (SCI), Centres, VinnExcellence Center for ECO2 Vehicle design.
    Jerrelind, Jenny
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Vehicle Dynamics.
    Stensson Trigell, Annika
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Vehicle Dynamics.
    Drugge, Lars
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Vehicle Dynamics.
    A Multi-Line Brush Based Tyre Model to Study the Rolling Resistance and Energy Loss2015In: Proceedings of 4th International Tyre Colloquium: Tyre Models for Vehicle Dynamics Analysis, Guildford, UK (2015), 2015Conference paper (Refereed)
    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.

  • 9.
    Davari, Mohammad Mehdi
    et al.
    KTH, School of Engineering Sciences (SCI), Centres, VinnExcellence Center for ECO2 Vehicle design. KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering.
    Jerrelind, Jenny
    KTH, School of Engineering Sciences (SCI), Centres, VinnExcellence Center for ECO2 Vehicle design. KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering.
    Stensson Trigell, Annika
    KTH, School of Engineering Sciences (SCI), Centres, VinnExcellence Center for ECO2 Vehicle design. KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering.
    Drugge, Lars
    KTH, School of Engineering Sciences (SCI), Centres, VinnExcellence Center for ECO2 Vehicle design. KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering.
    Extended Brush Tyre Model to Study Rolling Loss in Vehicle Dynamics Simulations2017In: International Journal of Vehicle Design, ISSN 0143-3369, E-ISSN 1741-5314, Vol. 73, no 4, p. 255-280Article in journal (Refereed)
    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.

  • 10.
    Davari, Mohammad Mehdi
    et al.
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Vehicle Dynamics. KTH, School of Engineering Sciences (SCI), Centres, VinnExcellence Center for ECO2 Vehicle design.
    Jerrelind, Jenny
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Vehicle Dynamics.
    Stensson Trigell, Annika
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Vehicle Dynamics.
    Edrén, Johannes
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Vehicle Dynamics.
    Investigating the Potential of Wheel Corner Modules in Reducing Rolling Resistance of Tyres2014In: Proceedings of FISITA "14 World Automotive Congress, Maastricht, Netherlands (2014), 2014Conference paper (Refereed)
    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.

  • 11.
    Davari, Mohammad Mehdi
    et al.
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Vehicle Dynamics.
    Jonasson, Mats
    KTH.
    Drugge, Lars
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering.
    Jerrelind, Jenny
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering.
    Stensson Trigell, Annika
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering.
    Rolling Loss Optimisation of an Over-actuated Vehicle using Predictive Control of Steering and Camber ActuatorsArticle in journal (Refereed)
  • 12.
    Davari, Mohammad Mehdi
    et al.
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Vehicle Dynamics.
    Jonasson, Mats
    KTH.
    Jerrelind, Jenny
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering.
    Stensson Trigell, Annika
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering.
    An Energy Oriented Control Allocation Strategy for Over-actuated Road VehiclesArticle in journal (Refereed)
  • 13.
    Davari, Mohammad Mehdi
    et al.
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Vehicle Dynamics.
    Jonasson, Mats
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Vehicle Dynamics.
    Jerrelind, Jenny
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Vehicle Dynamics.
    Stensson Trigell, Annika
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Vehicle Dynamics.
    Drugge, Lars
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Vehicle Dynamics.
    Rolling loss analysis of combined camber and slip angle control2016Conference paper (Refereed)
    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.

  • 14.
    Drugge, Lars
    et al.
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Vehicle Dynamics.
    Larsson, Tobias
    Luleå University of Technology.
    Stensson, Annika
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Vehicle Dynamics.
    Modelling and simulation of catenary-pantograph interaction2000In: Vehicle System Dynamics, ISSN 0042-3114, E-ISSN 1744-5159, Vol. 33, p. 202-213Article in journal (Refereed)
  • 15.
    Drugge, Lars
    et al.
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Vehicle Dynamics.
    Lennartsson, Anders
    Stensson Trigell, Annika
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Vehicle Dynamics.
    A laboratory model study of a railway current collection system2008In: Proceedings of the ASME Design Engineering Technical Conferences and Computers and Information in Engineering Conference, Vol 5, PTS A-C,, NEW YORK: AMER SOC MECHANICAL ENGINEERS , 2008, p. 1805-1810Conference paper (Refereed)
    Abstract [en]

    A vital system on modem high-speed electric trains is the overhead catenary system and the pantograph current collector. As speed limits are increased, train operators and railway engineers need measures of system performance in a number of situations. In this work a laboratory model is built to study the pantograph behaviour on curved track running on a catenary system with large stiffness variation. The model is designed to be simple, yet exhibit the most characteristic dynamic properties of the real system. Another objective is the possibility to run the pantograph at speeds near the wave propagation velocity of the contact wire. The situation of several trailing pantographs, with even spacing, which excites the system to steady state, is considered. Effects of changes in design features such as tension in the contact wire and torsion and translation stiffness of components in the pantograph are studied for different speeds. The interaction is complex and the performance depends on the dynamic properties of both the catenary system and the pantograph. The results show that the pantograph configuration mainly affects the size of amplitudes in the system while the contact wire tension influences at which velocities large amplitudes and contact losses occur.

  • 16.
    Edrén, Johannes
    et al.
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Vehicle Dynamics.
    Jerrelind, Jenny
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Vehicle Dynamics.
    Stensson Trigell, Annika
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Vehicle Dynamics.
    Drugge, Lars
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Vehicle Dynamics.
    Implementation and evaluation of force allocation control of a down-scaled prototype vehicle with wheel corner modules2013In: International Journal of Vehicle Systems Modelling and Testing, ISSN 1745-6436, Vol. 8, no 4, p. 335-363Article in journal (Refereed)
    Abstract [en]

    The implementation of wheel corner modules on vehicles creates new possibilities of controlling wheel forces through the utilisation of multiple actuators and wheel motors. Thereby new solutions for improved handling and safety can be developed. In this paper, the control architecture and the implementation of wheel slip and chassis controllers on a down-scaled prototype vehicle are presented and analysed. A simple, cost-effective force allocation algorithm is described, implemented and evaluated in simulations and experiments. Straight line braking tests were performed for the three different controller settings individual anti-lock brakes (ABS), yaw-torque-compensated ABS and force allocation using both wheel torque and steering angle control at each wheel. The results show that force allocation is possible to use in a real vehicle, and will enhance the performance and stability even at a very basic level, utilising very few sensors with only the actual braking forces as feedback to the chassis controller.

  • 17.
    Edrén, Johannes
    et al.
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Vehicle Dynamics.
    Jonasson, Mats
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Vehicle Dynamics.
    Jerrelind, Jenny
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Vehicle Dynamics.
    Stensson Trigell, Annika
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Vehicle Dynamics.
    Utilization of Vertical Loads by Optimization for Integrated Vehicle Control2012In: Proceedings of AVEC12, 11th Symposium on Advanced Vehicle Control, September 9-12, Seoul, Korea, 2012., 2012Conference paper (Other academic)
    Abstract [en]

    This paper presents results on how to optimally utilise vertical loading on individual wheels in order to improve vehicle performance during limit handling. Numerical optimisation has been used to find solutions on how the active suspension should be controlled and coordinated together with friction brakes and electric power assisted steering (EPAS). Firstly, it is investigated whether the brake distance can be shortened. Secondly, the performance during an evasive manoeuvre is investigated. The result shows that brake distance can be improved by at least 0.5 m and the speed through the evasive manoeuvre by roughly 1 km/h for the studied vehicle. Quick actuators is shown to give even better performance. These results provide guidance on how active suspension can be used to give significant improvements in vehicle performance.

  • 18.
    Edrén, Johannes
    et al.
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Vehicle Dynamics.
    Jonasson, Mats
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Vehicle Dynamics.
    Jerrelind, Jenny
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Vehicle Dynamics.
    Stensson Trigell, Annika
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Vehicle Dynamics.
    Drugge, Lars
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Vehicle Dynamics.
    Energy efficient cornering using over-actuationManuscript (preprint) (Other academic)
    Abstract [en]

    This work deals with utilisation of active steering and propulsion on individual wheels in order to improve a vehicle’s energy efficiency during a double lane change manoeuvre at moderate speeds. Through numerical optimization, solutions have been found for how wheel steering angles and propulsion torques should be used in order to minimise the energy consumed by the vehicle travelling through the manoeuvre. The results show that, for the studied vehicle, the cornering resistance can be reduced by 10% compared to a standard vehicle configuration. Based on the optimization study, simplified algorithms to control wheel steering angles and propulsion torques that are more energy efficient are proposed. These algorithms are evaluated in a simulation study that includes a path tracking driver model and an energy efficiency improvement of 6-9% based on a combined rear axle steering and torque vectoring control during cornering is found. The results indicate that in order to improve energy efficiency for a vehicle driving in a non-safety-critical situation the force distribution should be shifted towards the front wheels.

  • 19.
    Edrén, Johannes
    et al.
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Vehicle Dynamics.
    Jonasson, Mats
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Vehicle Dynamics.
    Jerrelind, Jenny
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Vehicle Dynamics.
    Stensson Trigell, Annika
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Vehicle Dynamics.
    Drugge, Lars
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Vehicle Dynamics.
    Energy efficient cornering using over-actuation2019In: Mechatronics (Oxford), ISSN 0957-4158, E-ISSN 1873-4006, Vol. 59, p. 69-81Article in journal (Refereed)
    Abstract [en]

    This work deals with utilisation of active steering and propulsion on individual wheels in order to improve a vehicle's energy efficiency during a double lane change manoeuvre at moderate speeds. Through numerical optimisation, solutions have been found for how wheel steering angles and propulsion torques should be used in order to minimise the energy consumed by the vehicle travelling through the manoeuvre. The results show that, for the studied vehicle, the energy consumption due to cornering resistance can be reduced by approximately 10% compared to a standard vehicle configuration. Based on the optimisation study, simplified algorithms to control wheel steering angles and propulsion torques that results in more energy efficient cornering are proposed. These algorithms are evaluated in a simulation study that includes a path tracking driver model. Based on a combined rear axle steering and torque vectoring control an improvement of 6–8% of the energy consumption due to cornering was found. The results indicate that in order to improve energy efficiency for a vehicle driving in a non-safety-critical cornering situation the force distribution should be shifted towards the front wheels.

  • 20.
    Edrén, Johannes
    et al.
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Vehicle Dynamics.
    Jonasson, Mats
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Vehicle Dynamics.
    Jerrelind, Jenny
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Vehicle Dynamics.
    Stensson Trigell, Annika
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Vehicle Dynamics.
    Drugge, Lars
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Vehicle Dynamics.
    Utilization of optimization solutions to control active suspension for decreased braking distanceManuscript (preprint) (Other academic)
    Abstract [en]

    This work deals with how to utilize active suspension on individual vehicle wheels in order to improve the vehicle performance during straight-line braking. Through numerical optimization, solutions have been found to how active suspension should be controlled and coordinated with friction brakes to shorten the braking distance. The results show that, for the studied vehicle, the braking distance can be shortened by more than 1 m when braking from 100 km/h. The applicability of these results is studied by investigating the approach for different vehicle speeds and actuator stroke limitations. It is shown that substantial improvements in the braking distance can also be found for lower velocities, and that the actuator strokes are an important parameter. To investigate the potential of implementing these findings in a real vehicle, a validated detailed vehicle model equipped with active struts is analysed. Simplified control laws, appropriate for on-board implementation and based on knowledge of the optimized solution, are proposed and evaluated. The results show that substantial improvements of the braking ability, and thus safety, can be made using this simplified approach. Particle model simulations have been made to explain the underlying physics and limitations of the approach. These results provide valuable guidance on how active suspension can be used to achieve significant improvements in vehicle performance with reasonable complexity and energy consumption.

  • 21.
    Edrén, Johannes
    et al.
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering.
    Jonasson, Mats
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering. Volvo Car Corporation, Sweden .
    Jerrelind, Jenny
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering.
    Trigell, Annika Stensson
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering.
    Drugge, Lars
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering.
    Utilisation of optimisation solutions to control active suspension for decreased braking distance2015In: Vehicle System Dynamics, ISSN 0042-3114, E-ISSN 1744-5159, Vol. 53, no 2, p. 256-273Article in journal (Refereed)
    Abstract [en]

    This work deals with how to utilise active suspension on individual vehicle wheels in order to improve the vehicle performance during straight-line braking. Through numerical optimisation, solutions have been found as regards how active suspension should be controlled and coordinated with friction brakes to shorten the braking distance. The results show that, for the studied vehicle, the braking distance can be shortened by more than 1 m when braking from 100 km/h. The applicability of these results is studied by investigating the approach for different vehicle speeds and actuator stroke limitations. It is shown that substantial improvements in the braking distance can also be found for lower velocities, and that the actuator strokes are an important parameter. To investigate the potential of implementing these findings in a real vehicle, a validated detailed vehicle model equipped with active struts is analysed. Simplified control laws, appropriate for on-board implementation and based on knowledge of the optimised solution, are proposed and evaluated. The results show that substantial improvements of the braking ability, and thus safety, can be made using this simplified approach. Particle model simulations have been made to explain the underlying physical mechanisms and limitations of the approach. These results provide valuable guidance on how active suspension can be used to achieve significant improvements in vehicle performance with reasonable complexity and energy consumption.

  • 22.
    Edrén, Johannes
    et al.
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Vehicle Dynamics.
    Jonasson, Mats
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Vehicle Dynamics.
    Nilsson, Andreas
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Vehicle Dynamics.
    Rehnberg, Adam
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Vehicle Dynamics.
    Svahn, Fredrik
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Vehicle Dynamics.
    Stensson Trigell, Annika
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Vehicle Dynamics.
    Modelica and Dymola for education in vehicle dynamics at KTH2009In: Proceedings from 7th Modelica Conference 2009, 2009, p. 775-783Conference paper (Refereed)
    Abstract [en]

    Dymola and Modelica has been used at KTH Vehicle Dynamics (KTHVD) for research work since 2000, see e.g. [1]. With the Vehicle Dynamics Library (VDL) [2], Modelica has become far more accessible for both researchers and students in the field of vehicle dynamics. Therefore a project aiming at introducing it as a tool in education was initiated in order to evaluate the current state of Dymola and Modelica as tools for wider use in education at the division. The work presented in this paper was realized as a part of a PhD course, where one of the tasks were to design dedicated exercises to illustrate fundamentals of vehicle dynamics for students.

  • 23.
    Edrén, Johannes
    et al.
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Vehicle Dynamics.
    Jonasson, Mats
    Vehicle Dynamics and Active Safety, Volvo Car Corporation, Göteborg, Sverige.
    Stensson Trigell, Annika
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Vehicle Dynamics.
    Drugge, Lars
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Vehicle Dynamics.
    Jerrelind, Jenny
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Vehicle Dynamics.
    The developement of a down-scaled over-actuated vehicle equipped with autonomous corner module functionality2010In: FISITA Proceedings 2010, paper F2010B056, 2010Conference paper (Refereed)
    Abstract [en]

    This paper presents the development of a functional down-scaled prototype of a passenger car with capability to control steering, wheel torques, wheel loads and camber individually. The adopted chassis technology is based on a modularised platform, referred to as Autonomous corner modules (ACM), which simplifies the re-use of components at the four corners of the vehicle and between different vehicles.

    This work gives an insight in the design of the vehicle and the selection of electrical actuators and sensors to provide all ACM functions. Since a part of the implemented chassis components do not admit to be scaled down at the same level, necessary design modifications are suggested. The problems of scaling, meaning that a down-scaled prototype cannot fully emulate a full-scaled vehicle’s all functions simultaneously, are a great disadvantage of down scaling. For example is gravity one desired parameter that is hard to physically scale down.

    In order to evaluate the behaviour of the down-scaled prototype, it is of high importance to establish the characteristics of the developed vehicle and its subsystems. In particular, tyre design is considered as complex. For this reason, different ideas of methods to confirm tyre characteristics are proposed.

    Also the paper presents the initial process of developing the prototype vehicle that is later to be used in vehicle dynamics research.

  • 24.
    Edrén, Johannes
    et al.
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Vehicle Dynamics.
    Sundström, Peter
    Modelon AB, Göteborg, Sweden.
    Jonasson, Mats
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Vehicle Dynamics.
    Jacobson, Bengt
    Chalmers Univerity of Technology, Gothenburg, Sweden.
    Andreasson, Johan
    Modelon AB, Lund, Sweden.
    Stensson Trigell, Annika
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Vehicle Dynamics.
    Road friction effect on the optimal vehicle control strategy in two critical manoeuvres2014In: International Journal of Vehicle Safety, ISSN 1479-3105, Vol. 7, no 2, p. 107-130Article in journal (Refereed)
    Abstract [en]

    This paper presents results on how to optimally negotiate two safety-critical vehicle manoeuvres depending on available actuators and road friction level. The motive for this research has been to provide viable knowledge of limitations of vehicle capability under the presence of environmental preview sensors, such as radar, camera and navigation. An optimal path is in this paper found by optimising the sequence of actuator requests during the two manoeuvres. Particular interest is paid on how the vehicle control strategy depends on friction. This work shows that actuation of forces and torques on and around the vehicle centre of gravity are all approximately scaled with the friction coefficient. However, this pattern is not valid at a wheel individual level, i.e. the optimal force allocation among the wheels differs under different friction conditions. One key is that lower friction level yields lower load transfer which substantially influences the wheel individual tyre force constraints.

  • 25.
    Erséus, Andreas
    et al.
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Vehicle Dynamics.
    Drugge, Lars
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Vehicle Dynamics.
    Stensson Trigell, Annika
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Vehicle Dynamics.
    A path tracking driver model with representation of driving skill2011In: International Journal of Vehicle Systems Modelling and Testing, ISSN 1745-6436, Vol. 6, no 2, p. 145-186Article in journal (Refereed)
    Abstract [en]

    A flexible and intuitive non-linear driver model is proposed, which allows setting of physically relevant parameters for representation of both typical high and typical low skill drivers in a path tracking scenario with constant speed. The model is equipped with a relatively simple internal vehicle model and is divided into three levels of driving skill: perceptual, anticipatory and interpretational skill; decisional skill; and execution skill. Validation of the model is performed using the results from moving base driving simulator tests with the double lane change scenario described in ISO 3888-1:1999. The parameter sets used for the model configuration are selected based on physical relevance to the model and optimisation is carried out with a Nelder-Mead implementation, showing that the model is able to resemble the characteristics of the driver types in the scenario for 70 km/h, and with adjustments being able to represent drivers at other speeds.

  • 26.
    Erséus, Andreas
    et al.
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Vehicle Dynamics.
    Stensson Trigell, Annika
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Vehicle Dynamics.
    Drugge, Lars
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Vehicle Dynamics.
    Characteristics of path tracking skill on a curving road2015In: International Journal of Vehicle Design, ISSN 0143-3369, E-ISSN 1741-5314, Vol. 67, no 1, p. 26-44Article in journal (Refereed)
    Abstract [en]

    The objective of this research work is to evaluate the relation of driver skill to measurements done when driving on a regular curving road, i.e., performing a primary driving task. A curving road scenario is designed using both clear sight and fog-limited sight distance. Measures are compared under equal conditions to identify the best separation of recruited driver types. A moving base simulator, VTI Simulator III, is used for the acquisition of driver metrics. Curves are found to be more reliable for identifying driver skill than straight road segments, and a number of measures show good performance in characterising driving skill under the tested conditions, both for clear sight and with the preview limited down to 30 m. The standard deviation proves to be very useful and qualifies for successful driver skill categorisation for commonly sampled data such as the lateral acceleration, yaw rate and steering wheel angle.

  • 27.
    Erséus, Andreas
    et al.
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Vehicle Dynamics.
    Stensson Trigell, Annika
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Vehicle Dynamics.
    Drugge, Lars
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Vehicle Dynamics.
    Methodology for finding parameters related to path tracking skill applied on a DLC-test in a moving base driving simulator2013In: International Journal of Vehicle Autonomous Systems, ISSN 1471-0226, E-ISSN 1741-5306, Vol. 11, no 1, p. 1-21Article in journal (Refereed)
    Abstract [en]

    The objective of this research is to develop and assess a method that can evaluate the relation of the driver's path tracking skill to a large number of vehicle parameters. The proposed methodology for comparison of measures under equal conditions is applied on test data from a double lane change test in a moving base simulator. Several measures are found to separate the recruited high and low skill driver groups, with the best results for the second part of the manoeuvre. Standard deviation qualifies for successful driver skill categorisation using commonly sampled data, e.g., steering wheel rate and angular acceleration.

  • 28.
    Favre, Tristan
    et al.
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Aerodynamics.
    Jarlmark Näfver, Jonas
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Vehicle Dynamics.
    Stensson Trigell, Annika
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Vehicle Dynamics.
    Efraimsson, Gunilla
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Aeroacoustics.
    Static coupling between detached-eddy simulations and vehicle dynamic simulation of a generic road vehicle model in unsteady crosswind with different rear configurationsArticle in journal (Other academic)
  • 29.
    Favre, Tristan
    et al.
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering. KTH, School of Engineering Sciences (SCI), Centres, VinnExcellence Center for ECO2 Vehicle design.
    Näfver, Jonas Jarlmark
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering. KTH, School of Engineering Sciences (SCI), Centres, VinnExcellence Center for ECO2 Vehicle design.
    Jerrelind, Jenny
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering. KTH, School of Engineering Sciences (SCI), Centres, VinnExcellence Center for ECO2 Vehicle design.
    Stensson Trigell, Annika
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering. KTH, School of Engineering Sciences (SCI), Centres, VinnExcellence Center for ECO2 Vehicle design.
    Efraimsson, Gunilla
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering. KTH, School of Engineering Sciences (SCI), Centres, VinnExcellence Center for ECO2 Vehicle design.
    Static coupling between detached-eddy simulations and vehicle dynamic simulations of a generic road vehicle model with different rear configurations in unsteady crosswind2016In: International Journal of Vehicle Design, ISSN 0143-3369, E-ISSN 1741-5314, Vol. 72, no 4, p. 332-353Article in journal (Refereed)
    Abstract [en]

    In this paper, aerodynamic loads of a generic car model obtained from advanced computational fluid dynamics (CFD) simulations are coupled to a vehicle dynamics model to enable the assessment of the on-road response. The influence of four rear configurations is studied. The different configurations yield large differences in yaw moments and side forces, which in turn result in considerable discrepancies in lateral displacements as well as yaw rates. From the simulations, it is seen that through balancing the location of the centre of pressure, the stiffness of the suspension bushings and the cornering stiffness of the tyres, it is possible to obtain stable vehicles in strong crosswind conditions for all four rear designs. The results show that monitoring the location of the aerodynamic centre of pressure with respect to the centre of gravity and the neutral steer point is essential for the possibility of designing stable vehicles in transient crosswind.

  • 30.
    Jerrelind, Jenny
    et al.
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Vehicle Dynamics.
    Drugge, Lars
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Vehicle Dynamics.
    Stensson Trigell, Annika
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Vehicle Dynamics.
    Nybacka, Mikael
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Vehicle Dynamics.
    Simulation of Vehicle-Overhead Power System Interaction on Electric Roads2012Conference paper (Refereed)
    Abstract [en]

    Due to the upcoming lack of oil and the environmental problems that conventional internal combustion engines are causing, electric vehicles have gained a growing interest during recent years. One solution to improve the efficiency of the existing road network is to make use of electric roads equipped with an overhead power system, thereby allowing also long-distance truck and bus transports to be powered by electricity without the need of heavy, bulky and expansive batteries.

    Providing electric power using an overhead power system has primarily been used in railway applications and only to some extent in road applications, for example in the case of trolley buses in urban areas. In this study, an overhead catenary system providing electric power to a long-distance truck by means of a pantograph mechanism that collects power through sliding contact with the overhead wire is analysed through simulation.

    A model of a truck equipped with a pantograph is developed and its interaction with an overhead catenary system model is simulated using the finite element method. The current collection quality is evaluated by analysing the pantograph-catenary contact force variation during the influence of different disturbances such as road irregularities and contact wire vibrations due to multiple pantographs.

    The study is an assessment of the possibility of using a conventional overhead power system developed for trains in a new context by providing power to long-distance road transports. The results show that the investigated disturbances influence the dynamics of the studied truck-pantograph-catenary system, nevertheless the contact force variation is within the allowed range according to the technical specifications for interoperability (TSI) for trains. It can be concluded that an overhead power system is a promising solution for a more environmentally friendly energy supply for trucks and buses at specific road sections.

  • 31.
    Jerrelind, Jenny
    et al.
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Vehicle Dynamics.
    Edrén, Johannes
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Vehicle Dynamics.
    Li, Shiruo
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Vehicle Dynamics.
    Davari, Mohammad Mehdi
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Vehicle Dynamics.
    Drugge, Lars
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Vehicle Dynamics.
    Stensson Trigell, Annika
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Vehicle Dynamics.
    Exploring active camber to enhance vehicle performance and safety2013Conference paper (Refereed)
    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.

  • 32.
    Jerrelind, Jenny
    et al.
    KTH, Superseded Departments, Vehicle Engineering. Luleå University of Technology, Division of Computer Aided Design, Department of Mechanical Engineering, Sweden.
    Stensson, Annika
    Luleå University of Technology, Division of Computer Aided Design, Department of Mechanical Engineering, Sweden.
    Braille printer Dynamics1999In: Proceedings of the ASME Design Engineering Technical Conferences, 1999Conference paper (Other academic)
  • 33.
    Jerrelind, Jenny
    et al.
    KTH, Superseded Departments, Aeronautical and Vehicle Engineering.
    Stensson, Annika
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Vehicle Dynamics.
    Nonlinear dynamic behaviour of coupled suspension systems2003In: Meccanica (Milano. Print), ISSN 0025-6455, E-ISSN 1572-9648, Vol. 38, no 1, p. 43-59Article in journal (Refereed)
    Abstract [en]

    A two degrees of freedom model of two coupled suspension systems characterised by piecewise linear stiffness has been studied. The system, representing a pantograph current collector head, is shown to be sensitive to changes in excitation and system parameters, possessing chaotic, periodic and quasiperiodic behaviour. The coupled system has a more irregular behaviour with larger motions than the uncoupled suspension system, indicating that the response from the uncoupled suspension system cannot be used as a worst case measure. Since small changes in system parameters and excitation affect the results drastically then wear and mounting as well as actual operating conditions are crucial factors for the system behaviour.

  • 34.
    Jerrelind, Jenny
    et al.
    Luleå University of Technology, Division of Computer Aided Design, Department of Mechanical Engineering, Sweden.
    Stensson, Annika
    Luleå University of Technology, Division of Computer Aided Design, Department of Mechanical Engineering, Sweden.
    Nonlinear dynamics of parts in engineering systems2000In: Chaos, Solitons & Fractals, ISSN 0960-0779, E-ISSN 1873-2887, Vol. 11, no 15, p. 2413-2428Article in journal (Refereed)
    Abstract [en]

    By definition, chaotic vibrations arise from nonlinear deterministic physical systems or non-random differential or difference equations. In numerous engineering systems there exist nonlinearities which might affect the dynamic behaviour of the system. The objectives in this work are to summarise previous work on nonlinear dynamics of engineering parts and products and to investigate if research on how nonlinear parts can effect the total behaviour of the products have been performed. It is found that common nonlinear parts are machine elements such as gears, bearings, brakes and suspension systems. The most studied part in a product is of impact hammer type. The products are ordinary products, from searing machines, drilling machines and printers to railway vehicles. In order to be able to design reliable products the methodology should be further developed to enable use by engineers. One can conclude that the effect of nonlinear parts on the total system behaviour is still a fairly uninvestigated area.

  • 35.
    Jonasson, Mats
    et al.
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Vehicle Dynamics. Volvo Car Corporation, Sweden .
    Andreasson, Johan
    Modelon AB, Sweden.
    Solyom, Stefan
    Volvo Car Corporation, Sweden.
    Jacobson, Bengt
    Volvo Car Corporation, Sweden.
    Stensson Trigell, Annika
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Vehicle Dynamics.
    Utilization of Actuators to Improve Vehicle Stability at the Limit: From Hydraulic Brakes Toward Electric Propulsion2011In: Journal of Dynamic Systems Measurement, and Control, ISSN 0022-0434, E-ISSN 1528-9028, Vol. 133, no 5, article id 051003Article in journal (Refereed)
    Abstract [en]

    The capability of over-actuated vehicles to maintain stability during limit handling is studied in this paper. A number of important differently actuated vehicles, equipped with hydraulic brakes toward more advanced chassis solutions, are presented. A virtual evaluation environment has specifically been developed to cover the complex interaction between the driver and the vehicle under control. In order to fully exploit the different actuators setup, and the hard nonconvex constraints they possess, the principle of control allocation by nonlinear optimization is successfully employed. The final evaluation is made by exposing the driver and the over-actuated vehicles to a safety-critical double lane change. Thereby, the differently actuated vehicles are ranked by a quantitative indicator of stability.

  • 36.
    Jonasson, Mats
    et al.
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Vehicle Dynamics.
    Andreasson, Johan
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Vehicle Dynamics.
    Stensson Trigell, Annika
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Vehicle Dynamics.
    Global force potential of over-actuated electric vehicles2010In: International Journal of Vehicle System Dynamics, ISSN 0042-3114, Vol. 48, no 9, p. 983-998Article in journal (Refereed)
    Abstract [en]

    This paper formulates force constraints of over-actuated road vehicles. In particular, focus is put on different vehicle configurations provided with electrical drivelines. It is demonstrated that a number of vehicles possesses non-convex tyre and actuator constraints, which have an impact on the way in which the actuators are to be used. By mapping the actuator forces to a space on a global level, the potential of the vehicle motion is investigated for the vehicles studied. It is concluded that vehicles with individual drive, compared with individual brakes only, have a great potential to yaw motion even under strong lateral acceleration.

  • 37.
    Jonasson, Mats
    et al.
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Vehicle Dynamics.
    Andreasson, Johan
    Stensson Trigell, Annika
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering.
    Modelling and parameterisation of a vehicle for validity under limit handling2008In: Proceedings of 6th Modelica Conference, 2008Conference paper (Refereed)
    Abstract [en]

    This paper describes how a vehicle model from the VehicleDynamics Library is configured, parameterized and validated for predicting limit handling maneuvers. Especially, attention is given to the selection of subsystem models with suitable levels-of-detail as well the selection of performed measurements and measurement equipment. A strong principle throughout the presented work is component-based design where parameterizations are done on sub-system levels, no tuning on the final vehicle models is made. As a final test, the vehicle model is exposed to a sinusoidal steering input. It turns out that the correspondence between the model used and the real vehicle is acceptable for the driving scenario selected up to the limit of adhesion.

  • 38.
    Jonasson, Mats
    et al.
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Vehicle Dynamics.
    Andreasson, Johan
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Vehicle Dynamics.
    Stensson Trigell, Annika
    Jacobsson, Bengt
    Modelling vehicle dynamics for limit handling: Strategies, experiments and validation2008In: Proceedings of the 9th International Symposium on Advanced Vehicle Control, AVEC´08, 2008, p. 202-207Conference paper (Refereed)
  • 39.
    Jonasson, Mats
    et al.
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering.
    Zetterström, S.
    Stensson Trigell, Annika
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering.
    Autonomous corner modules as an enabler for new vehicle chassis solutions2006In: FISTA TransactionArticle in journal (Refereed)
    Abstract [en]

    Demands for new functions and refined attributes in vehicle dynamics are leading to more complex and more expensive chassis design. To overcome this, there has been increasing interest in a novel chassis design that could be reused in the development process for new vehicle platforms and mainly allow functions to be regulated by software. The Autonomous Corner Module (ACM) was invented at Volvo Car Corporation (VCC) in 1998. The invention is based upon actively controlled functions and distributed actuation. The main idea is that the ACM should enable individual control of the functions of each wheel; propulsion/braking, alignment/steering and vertical wheel load. This is done by using hubmotors and by replacing the lower control arm of a suspension with two linear actuators, allowing them to control steering and camber simultaneously. Along with active spring/damper and wheel motors, these modules are able to individually control each wheel's steering, camber, suspension and spin velocity. This provides the opportunity to replace mechanical drive, braking, steering and suspension with distributed wheel functions which, in turn, enable new vehicle architecture and design.

    The aim of this paper is to present the vehicle dynamic potential of the ACM solution, by describing its possible uses and relating them to previous research findings. Associated work suggests chassis solutions where different fractions of the functions of the ACM capability have been used to achieve benefits in vehicle dynamics. For instance, ideas on how to use active camber control have been presented. Other studies have reported well-known advantages, such as, good transient yaw control from in-wheel motor propulsion and stable chassis behaviour from four-wheel steering, when affected by side wind. However, this technology also presents challenges. One example is how to control the relatively large unsprung mass that occurs due to the extra weight from the in-wheel motor. The negative influence from this source can be reduced by using active control of vertical forces. The implementation of ACM, or similar technologies, requires a well-structured hierarchy and control strategy. Associated work suggests methods for chassis control, where tyre forces can be individually distributed from a vehicle path description. The associated work predominately indicates that the ACM introduces new opportunities and shows itself to be a promising enabler for vehicle dynamic functions.

  • 40.
    Juhlin, Magnus
    et al.
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Vehicle Dynamics.
    Eriksson, Peter
    Stensson Trigell, Annika
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Vehicle Dynamics.
    The effect of steering feel on the crosswind performance of buses - Part I: Subjective assessmentArticle in journal (Other academic)
    Abstract [en]

    The steering feel is considered to be an important part of the on-centre handling characteristics of vehicles. Therefore, the steering feel is of interest when improving the crosswind performance of buses. In the present paper a methodology is proposed that utilizes a moving-base driving simulator to study the influence of steering feel on the subjective judgement of bus drivers regarding crosswind performance. Results achieved when using this method show that there exists a correlation between the steering feel and the subjective evaluation of crosswind performance. When the drivers are driving a bus with low crosswind sensitivity, it is shown that low yaw rate gradients are preferred for both the steering wheel torque and the steering wheel angle. For more crosswind-sensitive vehicles, the demand for higher yaw rate gradients increases. That is probably due to the increased need for corrections and the fact that more prompt driver corrections are facilitated by higher yaw rate gradients. It can therefore be concluded that, in order to help the driver in a crosswind situation, it would be valuable to be able to change the steering feel characteristics of the vehicle.

  • 41.
    Juhlin, Magnus
    et al.
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Vehicle Dynamics.
    Eriksson, Peter
    Stensson Trigell, Annika
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Vehicle Dynamics.
    The effect of steering feel on the crosswind performance of buses - Part II: Objective assessment and correlation with subjective judgementsArticle in journal (Other academic)
    Abstract [en]

    The steering feel is considered to be an important part of the on-centre handling characteristics of vehicles and therefore of interest when improving the crosswind performance of buses. In this paper a methodology is proposed which uses a moving-base driving simulator for studying the influence of steering feel on the objective judgement of crosswind performance. The results obtained with this method show that there exists a correlation between the steering feel and the objective evaluation of crosswind performance. The objective results show that the lateral deviation due to a crosswind gust is reduced for all levels of crosswind sensitivity when the yaw rate gradients referencing both the steering-wheel angle and the steering-wheel torque are increased, thereby minimising the maximum required steering power. This is in contrast to the subjective results, which showed that low yaw rate gradients were preferred when the centre of gravity was in the most forward position. The results presented in this study imply a great potential in using an adaptive steering system, since the steering feel that objectively is most suitable under crosswind excitation is not subjectively preferred for all the centre of gravity positions.

  • 42.
    Juhlin, Magnus
    et al.
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Vehicle Dynamics.
    Stensson Trigell, Annika
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Vehicle Dynamics.
    Eriksson, Peter
    Aerodynamic loads on buses due to crosswind gusts – On-road measurements2008In: Vehicle System Dynamics, ISSN 0042-3114, E-ISSN 1744-5159, Vol. 46, p. 827-835Article in journal (Refereed)
    Abstract [en]

    Bus and coach traffic is considered to be one of the safest means of travelling. Still, there is a problem with accidents due to crosswind gusts. Therefore it is a need of improving the crosswind performance of buses. As a part of the work with improving the crosswind performance a method for estimating the aerodynamic loads on a bus when exposed to natural crosswind is proposed. The method is based on measurements of the vehicle response and the tire forces from which the aerodynamic loads are estimated using inverse simulations. The results are also shown to agree well with the results of other studies based on wind tunnel measurements. The estimated aerodynamic loads are intended to be used in a future study on crosswind sensitivity using a moving base simulator.

  • 43. Kanchwala, Husain
    et al.
    Stensson Trigell, Annika
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Vehicle Dynamics.
    Vehicle handling control of an electric vehicle using active torque distribution and rear wheel steering2017In: International Journal of Vehicle Design, ISSN 0143-3369, E-ISSN 1741-5314, Vol. 74, no 4, p. 319-345Article in journal (Refereed)
    Abstract [en]

    There are two objectives of this work. First is to develop a detailed mathematical model of a vehicle. The second is to develop a controller which makes the vehicle follow desired dynamic characteristics. Suspension kinematics and compliance characteristics have been obtained from the complex suspension models developed in Adams Car (R). Vehicle roll-pitch interactions and variations of roll and pitch centres with respect to wheel travel are considered. The controller is developed as a combination of force allocation control and active rear wheel steering control. Reference trajectories of vehicle velocity, path geometry and vehicle slip angle are the inputs. The controller transforms these user inputs and generates wheel torques and steering commands. A desired value of yaw rate is maintained by generating a restoring yaw moment from unequal torque distribution, and side slip is substantially reduced by active rear wheel steering controller. Finally simulation results illustrate the suitability of the controller.

  • 44. Morales Sanchez, Francisco
    et al.
    Wideberg, Johan
    Stensson Trigell, Annika
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Vehicle Dynamics.
    Problems in using individual X-by-wire cornering modules2014In: International Journal of Heavy Vehicle Systems, ISSN 1744-232X, Vol. 21, no 1, p. 1-10Article in journal (Refereed)
    Abstract [en]

    This article discusses some mechanical problems which occur by using hub-motors and individual wheel steering on road vehicles. Several multi-body dynamic simulations have been done in order to illustrate the high reaction forces in the steering actuator. This paper is not about an individual steering or control per se but aims to analyse the different forces in a given steering system for different steering scenarios.

  • 45.
    Nilsson, Andreas
    et al.
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Vehicle Dynamics.
    Agebro, Markus
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Vehicle Dynamics.
    Stensson Trigell, Annika
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Vehicle Dynamics.
    Study of path tracking skill and strategy using a moving base simulator2007In: FISITA’06 World Automotive Congress, 2007Conference paper (Refereed)
  • 46.
    Nilsson, Andreas
    et al.
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Vehicle Dynamics.
    Stensson Trigell, Annika
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Vehicle Dynamics.
    Drugge, Lars
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Vehicle Dynamics.
    A path tracking scenario without preview for analysis of driver characteristics2008In: Proceedings of the 9th International Symposium on Advanced Vehicle Control, 2008Conference paper (Refereed)
  • 47.
    Nilsson, Andreas
    et al.
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Vehicle Dynamics.
    Stensson Trigell, Annika
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Vehicle Dynamics.
    Drugge, Lars
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Vehicle Dynamics.
    Methodology to find parameters characteristic to path tracking skill: DLC-test in a moving base simulator2009In: Proceedings of the 21st International Symposium: Dynamics of Vehicles on Roads and Tracks, 2009Conference paper (Refereed)
    Abstract [en]

    The objective of this work is to evaluate the driver skill relation to a large number of objective vehicle parameters, all measured in a moving base simulator used in the test. Recruitment of High skill and Low skill drivers is done based on self evaluations by the drivers in relation to driver type descriptions. A moving base simulator with a double lane change (DLC) scenario is used both for recruitment verification and measurement of parameter metrics. Here, a suggested method that is used for the comparison of measures under equal conditions is described, and the best separation between the two recruited driver types is found for the highest velocity with all drivers participating, 70 km/h, in the second part of the manoeuvre, e.g. by using standard deviation of steering wheel rate or angular acceleration.

  • 48.
    Noréus, Olof
    et al.
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Vehicle Dynamics.
    Stensson Trigell, Annika
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Vehicle Dynamics.
    Comparison of measured and simulated drawbar pull forsix wheeled vehicle with radial pneumatic tyres on sandIn: Journal of terramechanics, ISSN 0022-4898, E-ISSN 1879-1204Article in journal (Other academic)
    Abstract [en]

    To enable improved cross country characteristics of wheeled vehicles with individually controlled transmission on soft ground,suitable tyre/terrain models are needed. Here tyre/terrain models for simulating driving with both rigid and pneumatic wheels onsoft ground have been developed. A method to measure terrain parameters and drawbar pull for a six-wheeled vehicle on sand isproposed, tested and evaluated. The method is developed in order to be able to validate the proposed tyre/terrain models includingboth rigid and pneumatic wheels that are developed to simulate the behaviour of a six-wheeled vehicle with electric transmissionon soft ground. Tests were performed at different tyre pressures, and it is shown that the drawbar pull is vastly improved atlower tyre pressures. Since the tyre/terrain model uses terrain parameters such as pressure–sinkage and shear stress–displacementrelationships, the sand properties are measured with a Bevameter. Parameters in the pressure–sinkage relationship are estimated tofit the measured data. Both external and internal shearing properties of the sand are measured using a rubber coated shear ring anda shear ring with grousers, respectively. Shear curves of simple exponential form from the developed tyre/terrain models are shownto agree reasonably well with the measured shear behaviour. This will be the base in the development of a strategy to get improvedcross country characteristics of six-wheeled vehicles.

  • 49.
    Noréus, Olof
    et al.
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Vehicle Dynamics.
    Stensson Trigell, Annika
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Vehicle Dynamics.
    Control of at-the-limit handling behaviour of a six-wheeler: strategies based on individual steer and individual torque controlIn: Vehicle System Dynamics, ISSN 0042-3114, E-ISSN 1744-5159Article in journal (Other academic)
    Abstract [en]

    To simulate a six wheeled vehicle at the handling limit, a vehicle model with a brush tyre model is used in order to get physicallyreasonable simulation results during high combined slip conditions. Different vehicle configurations are considered, where frontwheel steering is combined with either second axle steering, rear wheel steering or individual wheel torque control. By applyingdifferent vehicle slip angles and thereby limiting the DOF of the vehicle model, the vehicle configurations are evaluated duringdifferent driving conditions similar to for example front wheel skidding and rear wheel skidding. The results show that by applyingindividual torque control to the front wheel steered vehicle, the performance is improved for all evaluated manoeuvres, and it is theonly method among the evaluated methods that significantly increases the achievable aligning torque during a rear wheel skid if thevehicle slip angle is larger than the maximum front wheel steering angle. Rear wheel steering, on the other hand, has negligibleeffect on the aligning torque during a rear wheel skid for the six-wheeler.

  • 50.
    Noréus, Olof
    et al.
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Vehicle Dynamics.
    Stensson Trigell, Annika
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Vehicle Dynamics.
    Measurement of terrain values and drawbar pullfor six wheeled vehicle on sand2008In: 16th International Conference of the International Society for Terrain-Vehicle Systems, Turin, 2008Conference paper (Other academic)
    Abstract [en]

    A method to measure terrain parameters and drawbar pull for a six-wheeled vehicle on sand is proposed,tested and evaluated. The method is developed in order to be able to validate previously proposedtire/terrain models that are developed to simulate the behaviour of a six-wheeled vehicle withelectric transmission on soft ground. Tests were performed at different tire pressures, and it is shownthat the drawbar pull is vastly improved at lower tire pressure. Since the tire/terrain model uses terrainparameters such as pressure–sinkage and shear stress–displacement relationships, the sand propertiesare measured with a Bevameter. Parameters in the pressure–sinkage relationship are estimated to fitthe measured data. Both external and internal shearing properties of the sand are measured using arubber coated shear ring and a shear ring with grousers, respectively. The measured shear behaviouris shown to agree reasonably well with shear curves of simple exponential form. This will be a basein the development of a strategy to get improved cross country characteristics of six-wheeled vehicleswith individually controlled electric transmission on soft ground.

12 1 - 50 of 72
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