Jenny Jerrelind

KTH Royal Institute of Technology | KTH · Centre for ECO2 Vehicle Design

Due to legislations introduced to prevent global warming, vehicle manufacturers must find new ways to reduce CO2 emissions. This paper explores a way to reduce rolling resistance by heat-insulating and covering a truck's wheelhouse. Truck tyre rolling resistance was measured at +5 °C ambient temperature for consecutive speed steps in a climate wind...

Autonomous driving and electrification make over-actuation technologies more feasible and advantageous. Integrating autonomous driving with over-actuation allows for the effective use of their respective strengths, e.g., for studying energy and time optimal control. To model AVs, several vehicle coordinate systems have been used, e.g., Cartesian, F...

Teleoperation is considered as a viable option to control fully automated vehicles (AVs) of Level 4 and 5 in special conditions. However, by bringing the remote drivers in the loop, their driving experience should be realistic to secure safe and comfortable remote control. Therefore, the remote control tower should be designed such that remote driv...

The automotive industry is heading towards a more objective approach to vehicle testing, but subjective evaluation is still an important part of the development process. Subjective evaluation in physical testing has environmental implications and is dependent on ambient conditions. A more repeatable, faster, safer and more cost-effective tool for s...

The range of an electrically assisted bicycle, which is constrained by the rider’s cycling ability and the battery capacity, is heavily influenced by rolling resistance. Furthermore, the magnitude of rolling resistance affects commuters’ motivation to decide whether to cycle or to choose another way to commute. This paper presents a way to simulate...

Effective emission control technologies and eco-friendly propulsion systems have been developed to decrease exhaust particle emissions. However, more work must be conducted on non-exhaust traffic-related sources such as tyre wear. The advent of automated vehicles (AVs) enables researchers and automotive manufacturers to consider ways to further dec...

Background: Rolling resistance and aerodynamic losses cause a significant part of a truck's energy consumption. Therefore there is an interest from both vehicle manufacturers and regulators to measure these losses to understand, quantify and reduce the energy consumption of vehicles. On-road measurements are particularly interesting because it enab...

Knowing the tire pressure during driving is essential since it affects multiple tire properties such as rolling resistance, uneven wear, and how prone the tire is to tire bursts. Tire temperature and cavity pressure are closely tied to each other; a change in tire temperature will cause an alteration in tire cavity pressure. This article gives insi...

Rolling resistance dictates a large part of the energy consumption of trucks. Therefore, it is necessary to have a sound understanding of the parameters affecting rolling resistance. This article proposes a semi-physical thermodynamic tyre rolling resistance model, which captures the essential properties of rolling resistance, such as transient cha...

The advent of autonomous vehicles (AVs) enables the utilisation of by-wire technologies, which can be employed for various purposes, including four-wheel steering (4WS). The integration of 4WS into AVs has the potential to enhance vehicle performance in terms of manoeuvrability, stability and path tracking. This research aims to investigate the app...

Advanced active safety systems play a crucial role in ensuring the safe driving of vehicles in critical conditions such as an obstacle avoidance manoeuvre. However, conventional techniques relying mainly on braking interventions may not result in the desired vehicle response in such situations. Over-actuation through the control of individual motio...

Teleoperation is considered as a viable option to control fully automated vehicles (AVs) of Level 4 and 5 in special conditions. However, by bringing the remote drivers in the loop, their driving experience should be realistic to secure safe and comfortable remote control.Therefore, the remote control tower should be designed such that remote drive...

Rolling resistance is causing a significant part of the energy consumption in truck applications, especially at low-speed levels. To better estimate the energy consumption or remaining driving range, the truck tyre rolling resistance must be understood well. Temperature is a vital parameter for rolling resistance estimations. This article shows tru...

Rolling resistance consumes a large portion of the generated powertrain torque and thus has a substantial effect on truck energy consumption and greenhouse gas emissions. EU labelling of tyres mandates the manufacturers to measure rolling resistance at +25 °C ambient temperature after stabilised rolling resistance has been established. This is a co...

Emission control technologies and propulsion systems are developed to decrease exhaust particle emissions. However, more work must be done on non-exhaust traffic related sources such as tyre wear. The driving conditions are the most dominant regarding tyre wear. The advent of automated vehicles enables automotive engineers to control the vehicle fo...

Trajectory planning is one of the challenging and critical functional layers for autonomous vehicles. The trajectory planning of autonomous vehicles can result in subjectively aggressive driving which might increase the motion sickness of the passengers. This study focuses on designing an optimal control problem using point mass and bicycle vehicle...

Accurate trajectory planning is crucial for safe driving of autonomous vehicles in critical driving manoeuvres. However, using simple models for trajectory planning in such conditions may result in unrealistic or unsafe trajectories. This paper evaluates various combinations of models, i.e., over-actuation and vehicle and tyre models, for trajector...

The introduction of autonomous vehicles is expected to change the transportation system radically. One of the essential factors that affect the acceptance and choice of autonomous driving is passenger comfort. All people in the autonomous vehicle will be passengers and be able to perform non-driving tasks like reading etc. which increases the likel...

The evolution of mobility is led by automated vehicles (AVs), as they are expected to decrease commute time and vehicle fuel consumption as well as significantly increase safety. One of the main limitations they face is motion sickness (MS), which could jeopardise AVs acceptance by the society. On one hand, AVs driving style is expected to be perce...

This paper investigates the tuning of motion cues in dynamic driving simulators for EPAS (Electronic power assisted steering) tuning in winter conditions. The study investigates the differences in frequency content of the vehicle states yaw rate and lateral acceleration between dry and winter EPAS tuning. Based on the results from this investigatio...

Due to increased environmental issues and for economic reasons, the automotive industry intensifies the research towards energy efficient driving, by also taking into consideration the comfort and road holding aspects. In this direction, efforts of modeling and minimising tyre wear, one of the main non-exhaust traffic related sources, are investiga...

Electric and hybrid propulsion systems for articulated vehicles have been gaining increased attention, with the aim to decrease exhaust particle emissions. However, the more environmentally-friendly electric or hybrid articulated vehicles are expected to have increased nonexhaust pollution-related sources because of their significantly increased ma...

Electric and hybrid propulsion systems for articulated vehicles have been gaining increased attention, with the aim to decrease exhaust particle emissions. However, the more environmentally-friendly electric or hybrid articulated vehicles are expected to have increased nonexhaust pollution-related sources because of their significantly increased ma...

Autonomous vehicles (AVs) are expected to have a great impact on mobility by decreasing commute time and vehicle fuel consumption and increasing safety significantly. However, there are still issues that can jeopardize their wide impact and their acceptance by the public. One of the main limitations is motion sickness (MS). Hence, the last year’s r...

Tyres are a vital vehicle component forming an interface between a vehicle and the road, enabling the generation of braking, steering and traction forces. However, they also generate rolling resistance which researchers have tried to minimise through the years for environmental and economic reasons. Despite numerous attempts to model rolling resist...

Autonomous vehicle technologies are rapidly growing and are expected to change transportation habits radically. Autonomous cars increase the likelihood of motion sickness by allowing everyone in the vehicle to become passengers and perform non-driving tasks such as reading, working, and socializing. Comfort is one of the critical factors in the acc...

Tyres are a vital component for handling and load carrying while also contributing to the operating cost and environmental impact. The innovations in tyre design are driven by the need to reduce greenhouse gases and to make a better compromise between conflicting tyre properties. To accurately simulate tyres and to make these compromises a represen...

Trajectory planning is a crucial component of autonomous driving systems. However, using simple vehicle models for trajectory planning may result in unrealistic reference trajectories, especially in critical driving conditions, endangering the safe driving of autonomous vehicles. This study explores the effect of model complexity on the trajectory...

Measurement methods to determine the rolling resistance of tyres during different operation conditions are essential in the work towards more energy efficient vehicles. One of the influential parameters is the tyre temperature distribution, which has a large impact on the rolling resistance. Today, the standardised test procedure to measure rolling...

Automated vehicles (AVs) are expected to lead the evolution of mobility. Motion sickness, known as car sickness, is one of the main issues AVs will face, and could jeopardise their wide impact. However, a limited work has been done on how the incorporation of suspension dynamics and its control could help. In this direction, this paper explores the...

Electric and hybrid propulsion systems have been developed for ground vehicles, driven by the motivation of decreasing the particle emissions from the exhaust of conventional propulsion systems. However, the more environmentally friendly fully or hybrid electric vehicles are expected to have increased non-exhaust pollution related sources compared...

Electric and hybrid propulsion systems for articulated vehicles have been getting more attention, with manufacturers heading towards the electrification of heavy vehicles. This is motivated by the goal to decrease the particle emissions from the exhaust of conventional propulsion systems. However, the more environmentally friendly fully electric or...

The evolution of mobility is led by automated vehicles (AVs), as they are expected to decrease commute time and vehicle fuel consumption as well as significantly increase safety. One of the main limitations they face is motion sickness (MS), which could jeopardise AVs acceptance by the society. On one hand, AVs driving style is expected to be perce...

Trajectory planning is a crucial component of autonomous driving systems. However, using simple vehicle models for trajectory planning may result in unrealistic reference trajectories, especially in critical driving conditions, endangering the safe driving of autonomous vehicles. This study explores the effect of model complexity on the trajectory p...

Due to increased environmental issues and for economic reasons, the automotive industry intensifies the research towards energy efficient driving, without though eglecting the aspects of comfort and vehicle handling. In this direction, efforts of modeling and minimising tyre wear, one of the main non-exhaust traffic related sources, are investigate...

This review addresses efforts made within the field of vehicle dynamics to contribute to the energy efficient operation of road and rail vehicles. Selected investigations of the research community to develop technology solutions to reduce energy consumption are presented. The study explores the impact and potential of relatively mature technologies...

Effective emission control technologies and novel propulsion systems have been developed for road vehicles, decreasing exhaust particle emissions. However, work has to be done on non-exhaust traffic related sources such as tyre–road interaction and tyre wear. Given that both are inevitable in road vehicles, efforts for assessing and minimising tyre...

The automotive industry is shifting its focus on energy efficient driving to tackle rising environmental issues. In this direction, as exhaust particle emissions continuously decrease, the attention is turned on non-exhaust traffic related sources in ground vehicles, such as the interaction between tyre and roads and the tyre wear. Given that the t...

The current state of global warming requires immediate measures to reduce greenhouse gases and resource efficient vehicles act as a part of the solution. Rolling resistance of truck tyres is one of the main contributors to the environmental impact of road freight transport. To achieve adequate range for future battery electric trucks, parameters in...

Reducing the rolling resistance for future vehicle designs creates a possibility to reduce the fuel consumption and make the future vehicles more economical and ecological. For electric vehicles it is also an enabler to increase their driving range per charge. When optimising for reduced rolling resistance, contradictory requirements such as force...

For at least 50 years, the interest in understanding and reducing the rolling resistance of pneumatic tyres has been growing. This interest is driven by the need to reduce vehicle fuel consumption and CO 2 -emissions, for environmental and economic reasons. The amount of rolling resistance generated depends on the vehicle type, tyre properties and...

A direct yaw moment control (DYC) for energy-efficiency and a DYC for stability of electric vehicles (EVs) are proposed. The DYC for energy-efficiency is active during non-safety-critical cornering manoeuvres to improve the energy-efficiency of EVs. The DYC for stability is active during safety-critical manoeuvres to keep the vehicle stable. A comb...

For sustainability reasons it is important to reduce energy consumption during driving. One contribution to energy savings is by using proper wheel torque distributions during manoeuvring. An active energy-efficient direct yaw moment control (DYC) for electric vehicles has previously been proposed by the authors, taking the motor efficiency map int...

An active energy-efficient direct yaw moment control (DYC) for in-wheel motor electric vehicles taking motor efficiency maps into consideration is proposed in this paper. The potential contribution of DYC to energy saving during quasi-steady-state cornering is analysed. The study in this paper has produced promising results which show that DYC can...

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 ene...

Actively controlling the camber angle to improve energy efficiency has recently gained interest due to the importance of reducing energy consumption and the driveline electrification trend that makes cost-efficient implementation of actuators possible. To analyse how much energy that can be saved with camber control, the effect of changing the camb...

Actively controlling the camber angle to improve energy efficiency has recently gained interest due to the importance of reducing energy consumption and the driveline electrification trend that makes cost-efficient implementation of actuators possible. To analyse how much energy that can be saved with camber control, the effect of changeing the cam...

The growing concerns about the environmental issues caused by vehicles and a strive for better fuel economy, urge the legislators to introduce conservative regulations on vehicle testing and homologation procedures. To have accurate evaluations, driving cycles that can sufficiently describe the vehicles’ conditions experienced during driving is a p...

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 numb...

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 for...

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...

The audible frequency range behaviour of a truck damper element, connected to surrounding structures by means of rubber bushings, is investigated, applying a mixed measurement/modelling procedure. The damper element properties are retrieved through an experimental procedure, while the rubber bushings are modelled using a finite element formulation...

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...

This work presents an analysis of the effects of non-linear characteristics of a top mount bushing in the wheel suspension of a vehicle when evaluating vehicle characteristics such as comfort and handling. The investigation is performed by comparing simulation results from a quarter car model when using a non-linear bushing model and an approximate...

Fault-tolerant vehicle design is an emerging inter-disciplinary research domain, which is of increased importance due to the electrification of automotive systems. The goal of fault-tolerant systems is to handle occuring faults under operational condition and enable the driver to get to a safe stop. This paper presents results from an extended surv...

Fault-tolerant vehicle design is an emerging inter-disciplinary research domain, which is of increased importance due to the electrification of automotive systems. The goal of fault-tolerant systems is to handle occuring faults under operational condition and enable the driver to get to a safe stop. This paper presents results from an extended surv...

Vehicle manufacturers are constantly pushed to reduce the aerodynamic drag of vehicles, for example by constructing lower vehicles with less road clearance. This, however, reduces the available margin for oscillations within the suspension. If the oscillation amplitude exceeds a critical value, the suspension will impact a bumpstop. Under periodic...

In this paper, nonsmooth fold bifurcations associated with the onset of low-relative-velocity (near-grazing) impacts in an oscillatory mechanical system are proposed as a potential operating principle for high-speed limit switches. Specifically, analytical, numerical, and experimental methods are employed to investigate the near-grazing transient b...

Continuous electric power supply, which is transferred from the contact wire to the train through a pantograph mechanism, is a necessity for a train to function satisfactory. Since various sources of nonlinearities are present, such as friction in the pantograph suspensions and impacts in the subsystems and at the excitation, there is a possibility...

A combined control scheme relying feedback-based local control in the vicinity of periodic system responses and global control based on a coarse-grained approximation to the nonlinear dynamics is developed to achieve a desirable dynamical behavior of a Braille printer impact hammer. The proposed control methodology introduces discrete changes in th...

A method is presented for controlling the persistence of a local attractor near a grazing periodic trajectory in a piecewise smooth dynamical system in the presence of discontinuous jumps in the state associated with intersections with system discontinuities. In particular, it is shown that a discrete, linear feedback strategy may be employed to re...

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...

This paper considers the dependence of the performance of a Braille printer impact hammer on system parameters, specifically the lag time between subsequent current pulses and the location of a back stop constraining the oscillations of the hammer core. Here, the goal is to improve the printer speed while maintaining readability of the Braille type...

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 p...

A Braille printer forms dots in paper, which are read by blind people. The dots are produced by hammers, which basically consist of a spring loaded moving core that is excited by electromagnetic forces. The system is characterised by non-linear properties such as electromagnetic forcing and impacts. Problems with quality, high temperature and noise...