| 1. |
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2021 Vehicle Dynamics seminar
- 2021
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Editorial proceedings (other academic/artistic)abstract
- The seminar is held annually. The full title of this year's seminar was "2021 Vehicle Dynamics seminar -- for Future Mobility ...and not only Lateral".
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| 2. |
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| 3. |
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Advances in Dynamics of Vehicles on Roads and Tracks : Proceedings of the 26th Symposium of the International Association of Vehicle System Dynamics, IAVSD 2019, August 12-16, 2019, Gothenburg, Sweden
- 2020
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Editorial proceedings (other academic/artistic)abstract
- This volume contains the official proceedings of the 26th IAVSD Symposium on Dynamics of Vehicles on Roads and Tracks, which took place on 12–16 August 2019, at the Lindholmen Conference Centre in Gothenburg, Sweden. The main objective of the International Association for Vehicle System Dynamics (IAVSD, see www.iavsd.org) is to promote the development of, and applications in, the field of ground vehicle system dynamics. The IAVSD Symposium on Dynamics of Vehicles on Roads and Tracks is a leading international symposium bringing together researchers, scientists and engineers from academia and industry to present and exchange their latest ideas and results. These biennial symposia, held at various locations around the world, have contributed greatly to a better understanding of ground vehicle system dynamics-related problems. The organisers of the 26th Symposium were the Department of Mechanics and Maritime Sciences, Chalmers Railway Mechanics (CHARMEC), which is the Centre of Excellence in Railway Mechanics at Chalmers University of Technology, and the Vehicle and Traffic Safety Centre at Chalmers (SAFER). Both centres are part of the Transport Area of Advance hosted at Chalmers University of Technology. The symposium was attended by 380 delegates from 28 countries and five continents (Africa, Asia, Australia, Europe and North America). Most participants arrived from China (88), Sweden (73), UK (36), Germany (32), Japan (25), Austria (18), Italy (12) and Korea (11). Each day of the symposium started with a plenary session and an invited state-of-the-art presentation (60 minutes). These state-of-the-art papers have been published in the journal Vehicle System Dynamics (Taylor & Francis), volume 57, issue number 7 (July 2019). After the morning coffee break, the presentations were divided into five parallel sessions with various themes on road and railway vehicle dynamics. The number of extended abstracts submitted to the symposium was 338 with 131 related to road vehicle dynamics and 207 to railway vehicle dynamics. After peer review by the International Scientific Committee, 63 road abstracts and 83 railway abstracts were selected for 30-minute oral presentations, while 38 road and 47 railway abstracts were selected for poster presentations (3-minute oral introduction followed by individual discussions in front of each poster). Out of those, 218 presentations were selected for publication as full papers in this book, which represents the official conference proceedings. Part of the chapters gathered in this book covers different topics in railway vehicle system dynamics such as adhesion and friction, vehicle modelling, condition monitoring, wheel and rail profiles, active suspension, switches and crossings, and wheel out-of-roundness. Further topics include vibration and control, track modelling, traction and braking, vehicle design and components, safety and derailment analysis, wheel‒rail contact, wheel and rail damage, pantograph‒catenary dynamics, and wheel and rail wear. The remaining chapters cover themes in road vehicle system dynamics such as advanced driver-assistance systems (ADAS), handling dynamics, driving automation, integrated chassis control and powertrain/driveline control. Further topics include state estimation, standards, assessment and validation, tyre modelling, suspension and ride, and specialised vehicles. We expect that this volume of the Lecture Notes in Mechanical Engineering, published by Springer Nature, will serve as a timely reference guide and a source of inspiration for scientists and engineers in the field of ground vehicle system dynamics.
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| 4. |
- Askerdal, Mikael, 1975, et al.
(author)
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Motion resistance modelling and validation in winter conditions with varying air drag
- 2024
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In: Vehicle System Dynamics. - 1744-5159 .- 0042-3114. ; In Press
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Journal article (peer-reviewed)abstract
- Range prediction is vital for battery electric vehicles, and the main source of errors in range prediction is often the uncertainty in motion resistance. Rig and wind tunnel measurements can be used to find the motion resistance of a specific vehicle combination under specified weather conditions. However, real-life variation of the operating conditions of heavy-duty vehicles makes testing impractical. This paper proposes and validates a model of motion resistance with parameters adapted to actual road weather conditions. The model is validated in winter conditions with varying wind, using a vehicle equipped with a wind sensor. The results show that the proposed model captures the motion resistance with high accuracy. Results also indicate that it is crucial to take weather effects into account when modelling motion resistance, particularly in winter conditions.
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| 5. |
- Augusto, Bruno, 1986-, et al.
(author)
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Coupling forces in the B-triple and truck-B-double combinations : An extension of the 18868 ISO standard for D- and V-values and analysis of the normative case
- 2020
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Reports (other academic/artistic)abstract
- The forces in the couplings of articulated vehicle combinations, propel and fully determine the path of any towed unit thus playing a significant role in the vehicle behavior. A failure in the coupling could potentially have a devastating effect if it occurs while driving in traffic. To prevent this from happening, states and road authorities impose requirements in terms of tolerated forces on any coupling selection. The current legal requirement framework is based on an ISO standard, that stipulates minimum force levels that the couplings should stand. These forces have been derived under semi-empirical assumptions for a set of five vehicle combinations. The present report aims to extend the coupling requirements to two vehicle combinations that are candidates to become legal on the public road network. Due to the semi-empirical nature of the ISO standard, validation needed to be performed. The here presented requirements for the two new combinations were validated against simulation models and checked for reasonable requirements for some example weights of the combinations. The proposed requirements are aligned with the existing requirements derived from the ISO standard. This implies that they could be used to form the legal requirements on these vehicle combinations. However, further investigations on well-grounded deduced requirements should be performed to secure safety margins.
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| 6. |
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Automated Comfortable Docking at Bus Stops
- 2021
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Editorial proceedings (other academic/artistic)abstract
- This proceedings presentation illustrates the optimization problem of autonomous bus parallel parking subjected to ride discomfort while navigating in a path with rectangular geometry constraints. During bus parking, passengers - especially standing- can experience discomfort due to acceleration and jerk components. In our project, a novel discomfort model was derived, utilizing acceleration and jerk data. This model was then implemented in an optimization problem to minimize discomfort. Simulation results and experiment results have been shown. The experiment was conducted using Volvo Autonomous Bus.
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| 7. |
- Blissing, Björn, 1978-
(author)
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Driving in Virtual Reality : Requirements for automotive research and development
- 2020
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Doctoral thesis (other academic/artistic)abstract
- In the last decades, there has been a substantial increase in the development of complex active safety systems for automotive vehicles. These systems need to be tested for verification and validation to ensure that the system intervenes in the correct situations using the correct measures. There are multiple methods available to perform such testing. Software-in-the-loop and hardware-in-the-loop testing offer effective driverless testing. Other methods increase the fidelity by including human drivers, such as driving simulators and experiments performed at test tracks.This thesis examines vehicle-in-the-loop testing, an innovative method where the driver of a real vehicle wears a head-mounted display that displays virtual targets. This method combines the benefits of driving simulators with the benefits of using a real vehicle on a test track. Driving simulators offer repeatability, safety, and the possibility of complex interactions between actors. In contrast, the real vehicle provides the correct vehicle dynamics and motion feedback.There is a need to know how the technology behind the method might influence the results from vehicle-in-the-loop testing. Two techniques for vehicle-in-the-loop systems are studied. The first involves video-see through head-mounted displays, where the focus of the research is on the effects of visual latency on driving behavior. The results show that lateral driving behavior changes with added latency, but longitudinal behavior appears unaffected. The second system uses an opaque head-mounted display in an entirely virtual world. The research shows that this solution changes speed perception and results in a significant degradation in performance of tasks dependent on visual acuity.This research presents results that are relevant to consider when developing vehicle-in-the-loop platforms. The results are also applicable when choosing scenarios for this test method.
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| 8. |
- Blissing, Björn, 1978-, et al.
(author)
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The Effects on Driving Behavior When Using a Head-Mounted Display in a Dynamic Driving Simulator
- 2022
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In: ACM Transactions on Applied Perception. - : Association for Computing Machinery. - 1544-3558 .- 1544-3965. ; 19:1, s. 1-18
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Journal article (peer-reviewed)abstract
- Driving simulators are established tools used during automotive development and research. Most simulators use either monitors or projectors as their primary display system. However, the emergence of a new generation of head-mounted displays has triggered interest in using these as the primary display type. The general benefits and drawbacks of head-mounted displays are well researched, but their effect on driving behavior in a simulator has not been sufficiently quantified.This article presents a study of driving behavior differences between projector-based graphics and head-mounted display in a large dynamic driving simulator. This study has selected five specific driving maneuvers suspected of affecting driving behavior differently depending on the choice of display technology. Some of these maneuvers were chosen to reveal changes in lateral and longitudinal driving behavior. Others were picked for their ability to highlight the benefits and drawbacks of head-mounted displays in a driving context.The results show minor changes in lateral and longitudinal driver behavior changes when comparing projectors and a head-mounted display. The most noticeable difference in favor of projectors was seen when the display resolution is critical to the driving task. The choice of display type did not affect simulator sickness nor the realism rated by the subjects.
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| 9. |
- Bruzelius, Fredrik, 1974, et al.
(author)
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Low speed performance based standards for the Nordic countries
- 2021
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In: International Journal of Heavy Vehicle Systems. - : Inderscience Publishers. - 1741-5152 .- 1744-232X. ; 28:1, s. 110-124
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Journal article (peer-reviewed)abstract
- Performance based standards (PBS) is an effective regulator policy which can address variation complexity in vehicle combinations. This paper investigates aspects of using computer simulation and mathematical models to assess the performance of vehicle combinations in low speed manoeuvring, and in particular roundabouts. A set of 22 vehicle combinations, including existing conventional heavy vehicles as well as prospective high capacity vehicles, is used to study the effects of turn angle and road surface conditions on the friction demand and swept path measures. Simulation results suggest that the friction demand measure is dependent on the available grip. This makes it hard to interpret and may not be suitable in the PBS framework. The swept path measure is relatively unaffected by friction levels, and can hence be calculated with simple and robust expressions not considering the road interaction. However, turn angle affects the swept path measure considerably, and should be addressed when designing the PBS scheme implementation into the legislations.
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| 10. |
- Bruzelius, Fredrik, 1974-, et al.
(author)
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The influence of tractor lengths on traffic safety and efficiency : a simulation study
- 2022
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Reports (other academic/artistic)abstract
- Several different heavy vehicle combinations are allowed on the Swedish road network. A commonly seen combination is the tractor and semi-trailer combination with a maximum total length of 16.5 meters. The legal limitation on the total length of the combination has led to the use of a short tractor to make space for more goods on the trailer. There is a concern that the shortness of the tractors will have a negative consequence on traffic safety and the ability to negotiate uphills. The short wheelbase of the tractor and the weight imbalance between the tractor and the semitrailer could be an issue when braking and negotiating turns. This study was ordered by the Swedish Transport Agency to investigate the traffic safety aspects and hill-climbing problems of certain heavy vehicle combinations. The concerns raised should be investigated from a vehicle dynamical point of view for the vehicle combinations in question and compare them with other common vehicle combinations through a simulation study. A set of tractor and semitrailer combinations have been simulated in severe conditions and maneuvers to investigate the vehicle response and its dependencies with respect to the wheelbase of the tractor, coupling length, fifth wheel lubrication, and road surface conditions. Whenever meaningful, a comparison was made with a Nordic combination (truck and full trailer) as well as a B-double combination (tractor, link trailer, and trailer). The overall result of the simulation study is that the tractor and semitrailer combination is a stable combination, which outperforms the longer and heavier Nordic and B-double combinations in all the measured situations and maneuvers where comparison is meaningful. Furthermore, the wheelbase of the tractor seems to have a very minor effect on the performance of the vehicle combinations.
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