| 1. |
- Andersson, Mats, et al.
(författare)
-
Road Friction Estimation
- 2007
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- This project is part of the Swedish IVSS program. The aim of IVSS is to stimulate research and development for the road safety of the future. Road conditions with low friction have been identified as a frequent cause of traffic accidents. Therefore, technology to automaticallydetect changes in road conditions and alert the driver or take proper actions with active driver support systems would be a key contribution to increased road safety.The aim of this project was to investigate the possibilities to estimate the tire to road friction.Three different approaches have been developed and evaluated, from concept to early prototypes in test vehicles. In the first method, the estimation of the coefficient of friction is based on the forces and torques that are produced at the front tires at cornering maneuvers.The second method is based on a physical model of the tire behavior and estimates road friction from information on the forces that are produced at straight driving. The third method is based on an optical sensor that classifies the road surface ahead of the vehicle.The three methods have been successfully evaluated in proving ground and public road tests in summer and winter conditions with different tires, and have been compared with reference measurements. The conclusion is that all three methods can be used for tire to road frictionestimation and are recommended for further development and industrialization.
|
|
| 2. |
-
2021 Vehicle Dynamics seminar
- 2021
-
Proceedings (redaktörskap) (övrigt vetenskapligt/konstnärligt)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".
|
|
| 3. |
|
|
| 4. |
-
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
-
Proceedings (redaktörskap) (övrigt vetenskapligt/konstnärligt)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.
|
|
| 5. |
- Albinsson, Anton, 1989, et al.
(författare)
-
Design of tyre force excitation for tyre–road friction estimation
- 2017
-
Ingår i: Vehicle System Dynamics. - : Informa UK Limited. - 1744-5159 .- 0042-3114. ; 55:2, s. 208-230
-
Tidskriftsartikel (refereegranskat)abstract
- Knowledge of the current tyre–road friction coefficient is essential for future autonomous vehicles. The environmental conditions, and the tyre–road friction in particular, determine both the braking distance and the maximum cornering velocity and thus set the boundaries for the vehicle. Tyre–road friction is difficult to estimate during normal driving due to low levels of tyre force excitation. This problem can be solved by using active tyre force excitation. A torque is added to one or several wheels in the purpose of estimating the tyre–road friction coefficient. Active tyre force excitation provides the opportunity to design the tyre force excitation freely. This study investigates how the tyre force should be applied to minimise the error of the tyre–road friction estimate. The performance of different excitation strategies was found to be dependent on both tyre model choice and noise level. Furthermore, the advantage with using tyre models with more parameters decreased when noise was added to the force and slip ratio.
|
|
| 6. |
- Albinsson, Anton, 1989, et al.
(författare)
-
Estimation of the inertial parameters of vehicles with electric propulsion
- 2016
-
Ingår i: Proceedings of the Institution of mechanical engineers. Part D, journal of automobile engineering. - : Sage Publications. - 0954-4070 .- 2041-2991. ; 230:9, s. 1155-1172
-
Tidskriftsartikel (refereegranskat)abstract
- More accurate information about the basic vehicle parameters can improve the dynamic control functions of a vehicle. Methods for online estimation of the mass, the rolling resistance, the aerodynamic drag coefficient, the yaw inertia and the longitudinal position of the centre of gravity of an electric hybrid vehicle is therefore proposed. The estimators use the standard vehicle sensor set and the estimate of the electric motor torque. No additional sensors are hence required and no assumptions are made regarding the tyre or the vehicle characteristics. Consequently, all information about the vehicle is available to the estimator.The estimators are evaluated using both simulations and experiments. Estimations of the mass, the rolling resistance and the aerodynamic drag coefficient are based on a recursive least-squares method with multiple forgetting factors. The mass estimate converged to within 3% of the measured vehicle mass for the test cases with sufficient excitation that were evaluated. Two methods to estimate the longitudinal position of the centre of gravity and the yaw inertia are also proposed. The first method is based on the equations of motion and was found to be sensitive to the measurement and parameter errors. The second method is based on the estimated mass and seat-belt indicators.This estimator is more robust and reduces the estimation error in comparison with that obtained by assuming static parameters. The results show that the proposed method improves the estimations of the inertial parameters. Hence, it enables online non-linear tyre force estimators and tyre-model-based tyre–road friction estimators to be used in production vehicles.
|
|
| 7. |
- Albinsson, Anton, 1989, et al.
(författare)
-
Evaluation of vehicle-based tyre testing methods
- 2019
-
Ingår i: Proceedings of the Institution of Mechanical Engineers. Part D, Transport engineering. - : SAGE Publications. - 2041-2991 .- 0954-4070. ; 233:1, s. 4-17
-
Tidskriftsartikel (refereegranskat)abstract
- The demand for reduced development time and cost for passenger cars increases the strive to replace physical testing with simulations. This leads to requirements on the accuracy of the simulation models used in the development process. The tyres, the only components transferring forces from the road to the vehicle, are a challenge from a modelling and parameterization perspective. Tests are typically performed on flat belt tyre testing machines. Flat belt machines offers repeatable and reliable measurements. However, differences between the real world road surface and the flat belt can be expected. Hence, when using a tyre model based on flat belt measurements in full vehicle simulations, differences between the simulations and real prototype testing can be expected as well. Vehicle-based tyre testing can complement flat belt measurements by allowing reparameterization of tyre models to a new road surface. This paper describes an experimental vehicle-based tyre testing approach that aims to parameterize force and moment tyre models compatible with the standard tyre interface. Full-vehicle tests are performed, and the results are compared to measurements from a mobile tyre testing rig on the same surface and to measurements on a flat belt machine. The results show that it is feasible to measure the inputs and outputs to the standard tyre interface on a flat road surface with the used experimental setup. The flat belt surface and the surface on the test track show similar characteristics. The maximum lateral force is sensitive to the chosen manoeuvres, likely due to temperature differences and to vibrations at large slip angles. For tyre models that do not model these effects, it is vital to test the tyres in a manoeuvre that creates comparable conditions for the tyres as the manoeuvre in which the tyre model will be used.
|
|
| 8. |
- Albinsson, Anton, 1989, et al.
(författare)
-
Friction utilization for tyre-road friction estimation on snow: an experimental study
- 2017
-
Ingår i: 13th International Symposium on Advanced Vehicle Control, AVEC'16. - 9781315265285 ; , s. 541-546
-
Konferensbidrag (refereegranskat)abstract
- Friction estimation using effect-based approaches are challenging during normal driving due to the large tyre excitation needed for an accurate estimate. The required excitation level varies for different tyres, road surfaces, road conditions and tyre models used in the estimator. Previous research has investigated the required friction utilization on different surfaces but due to the small sample sizes it is hard to draw any general conclusions. This paper investigates the tyre excitation required to estimate the tyre-road friction coefficient with a generic estimator for 76 different tyres on snow for five different tyre models and for different levels of measurement noise.
|
|
| 9. |
- Albinsson, Anton, 1989, et al.
(författare)
-
Identification of tyre characteristics using active force excitation
- 2016
-
Ingår i: The Dynamics of Vehicles on Roads and Tracks - Proceedings of the 24th Symposium of the International Association for Vehicle System Dynamics, IAVSD 2015. - : CRC Press. - 9781138028852 ; , s. 501-510
-
Konferensbidrag (refereegranskat)abstract
- Knowledge of the maximum tyre-road friction coefficient can improve active safety systems by defining actuator boundaries and adaptable intervention thresholds. Estimation of the coefficient of friction based on tyre response measurements requires large level of force excitation. Under normal driving conditions, manoeuvres with large tyre utilizations are rare. This study investigates a method where wheel torques with opposite signs are applied to the front and rear axle simultaneously. This procedure allows for an intervention with large tyre excitations without disturbing the motion of the vehicle. The intervention is evaluated in simulations and experiments. Further, a method is proposed which does not require measurement of the vehicle longitudinal velocity. The results show that it is possible to estimate the current friction coefficient with the proposed method, although the assumption made in the proposed method makes the friction estimate sensitive to measurement noise on the wheel speed signal.
|
|
| 10. |
- Albinsson, Anton, 1989, et al.
(författare)
-
Required friction utilization for friction estimation on wet asphalt, an experimental study
- 2018
-
Ingår i: The Dynamics of Vehicles on Roads and Tracks. - : CRC Press/Balkema. - 9781138035713 ; 1, s. 407-412
-
Konferensbidrag (refereegranskat)abstract
- Real-time information about the friction coefficient between the tyre and the road can be used to improve active safety systems and is an enabler for autonomous vehicles. Large tyre force excitation is normally required to obtain an accurate friction estimate. This paper quantifies this requirement for four different tyre models on wet salted asphalt at water freezing temperatures. Cost functions and different tyre models are evaluated and the results are compared to a previous study performed for snow conditions. The suitability of commonly used tyre models for friction estimation on snow and wet asphalt has thus been investigated.
|
|
| 11. |
- Albinsson, Anton, 1989, et al.
(författare)
-
Scaling tire models to different road surfaces using an external IMU and K&C measurements
- 2018
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Accurate simulation models are required for virtual verification of vehicle dynamics and chassis control functions. The force and moment characteristics of tires depend on the road surface. To achieve good simulation and testing correlation accuracy, an accurate tire model that is representative for the actual road surface is required. This study investigates a cost-efficient method to scale Pacejka 2002 models, based on flat belt measurements, to a real road surface using simple instrumentation and static measurements of a test vehicle. The feasibility of the method is illustrated using measurements, where the propagation of measurement error to model error is investigated.
|
|
| 12. |
- Albinsson, Anton, et al.
(författare)
-
Tire Force Estimation Based on the Recursive Least Square Method Utilizing Wheel Torque Measurement
- 2014
-
Ingår i: 12th International Symposium on Advanced Vehicle Control September 22-26, 2014. - : Society of Automotive Engineers of Japan. ; , s. 294-299
-
Konferensbidrag (refereegranskat)abstract
- This study investigates a new tire force estimator based on the recursive least square (RLS) method. Tire force estimation with known driving wheel torque is studied and compared to the case with torque estimation from the internal combustion engine. This is motivated by a future scenario with electric propulsion, which reasonably gives improved wheel torque estimations. Sensitivity to vehicle parameters and challenges with individual lateral tire force estimation are also investigated. The results, experimental and simulation data, show good performance and potential for tire force estimation using the RLS method.
|
|
| 13. |
- Albinsson, Anton, 1989, et al.
(författare)
-
Tire Force Estimation Utilizing Wheel Torque Measurements and Validation in Simulations and Experiments
- 2014
-
Ingår i: 12th International Symposium on Advanced Vehicle Control (AVEC '14), Tokyo Japan. ; , s. 294-299
-
Konferensbidrag (refereegranskat)abstract
- This study investigates a new tire force estimator based on the recursive least square (RLS) method. Tire force estimation with known driving wheel torque is studied and compared to the case with torque estimation from the internal combustion engine. This is motivated by a future scenario with electric propulsion, which reasonably gives improved wheel torque estimations. Sensitivity to vehicle parameters and challenges with individual lateral tire force estimation are also investigated. The results, experimental and simulation data, show good performance and potential for tire force estimation using the RLS method.
|
|
| 14. |
- Albinsson, Anton, 1989, et al.
(författare)
-
Tire Lateral Vibration Considerations in Vehicle-Based Tire Testing
- 2019
-
Ingår i: Tire Science and Technology. - : The Tire Society. - 0090-8657 .- 1945-5852. ; 47:3, s. 211-231
-
Tidskriftsartikel (refereegranskat)abstract
- Vehicle-based tire testing can potentially make it easier to reparametrize tire models for different road surfaces. A passenger car equipped with external sensors was used to measure all input and output signals of the standard tire interface during a ramp steer maneuver at constant velocity. In these measurements, large lateral force vibrations are observed for slip angles above the lateral peak force with clear peaks in the frequency spectrum of the signal at 50 Hz and at multiples of this frequency. These vibrations can lower the average lateral force generated by the tires, and it is therefore important to understand which external factors influence these vibrations. Hence, when using tire models that do not capture these effects, the operating conditions during the testing are important for the accuracy of the tire model in a given maneuver. An Ftire model parameterization of tires used in vehicle-based tire testing is used to investigate these vibrations. A simple suspension model is used together with the tire model to conceptually model the effects of the suspension on the vibrations. The sensitivity of these vibrations to different operating conditions is also investigated together with the influence of the testing procedure and testing equipment (i.e., vehicle and sensors) on the lateral tire force vibrations. Note that the study does not attempt to explain the root cause of these vibrations. The simulation results show that these vibrations can lower the average lateral force generated by the tire for the same operating conditions. The results imply that it is important to consider the lateral tire force vibrations when parameterizing tire models, which does not model these vibrations. Furthermore, the vehicle suspension and operating conditions will change the amplitude of these vibrations and must therefore also be considered in maneuvers in which these vibrations occur.
|
|
| 15. |
- Albinsson, Anton, 1989, et al.
(författare)
-
Validation of vehicle-based tyre testing methods
- 2019
-
Ingår i: Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering. - : SAGE Publications. - 2041-2991 .- 0954-4070. ; 233:1, s. 18-27
-
Tidskriftsartikel (refereegranskat)abstract
- The development process for passenger cars is both time- and resource-consuming. Full vehicle testing is an extensive part of the development process that consumes large amount of resources, especially within the field of vehicle dynamics and active safety. By replacing physical testing with complete vehicle simulations, both the development time and cost can potentially be reduced. This requires accurate simulation models that represent the real vehicle. One major chal- lenge with full vehicle simulation models is the representation of tyres in terms of force and moment generation. The force and moment generation of the tyres is affected by both operating conditions and road surface. Vehicle-based tyre testing offers a fast and efficient way to rescale force and moment tyre models to different road surfaces, in this study the Pacejka 2002 model. The resulting tyre model is sensitive to both the operating conditions during testing and the road surface used. This study investigates the influence of the slip angle sweep rate and road surface on the lateral tyre force characteristics of the fitted tyre model. Tyre models fitted to different manoeuvres are compared and the influence on the full vehicle behaviour is investigated in IPG Carmaker. The results show that by using the wrong road surface, the resulting tyre model can end up outside the tolerances specified by the ISO standard for vehicle simulation model verifi- cation in steady-state cornering. The use of Pacejka 2002 models parameterized in a steady-state manoeuvre to simulate the vehicle behaviour in sine-with-dwell manoeuvres is also discussed.
|
|
| 16. |
- Askerdal, Mikael, 1975, et al.
(författare)
-
Motion resistance modelling and validation in winter conditions with varying air drag
- 2024
-
Ingår i: Vehicle System Dynamics. - 1744-5159 .- 0042-3114. ; In Press
-
Tidskriftsartikel (refereegranskat)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.
|
|
| 17. |
- Augusto, Bruno, 1986-, et al.
(författare)
-
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
-
Rapport (övrigt vetenskapligt/konstnärligt)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.
|
|
| 18. |
-
Automated Comfortable Docking at Bus Stops
- 2021
-
Proceedings (redaktörskap) (övrigt vetenskapligt/konstnärligt)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.
|
|
| 19. |
- Blissing, Björn, 1978-, et al.
(författare)
-
A Technical Platform using Augmented Reality for Active Safety Testing
- 2015
-
Ingår i: 2015 Road Safety & Simulation International Conference Proceedings. - Orlando, USA : University of Central Florida. - 9781495174452 ; , s. 793-803
-
Konferensbidrag (refereegranskat)abstract
- This paper describes the design of a video see-through augmented reality system for active safety testing. The development is explained in detail, with focus on the design considerations for the different subsystems. It is shown that it is possible to build a system using available commercial off-the-shelf components, while still maintaining the performance needed for the intended application. Accuracy and resolution requirements of the tracking systems are discussed along with measurement methods. We also examine how to use the hardware efficiently to minimize latency and a device to measure and quantify end-to-end latency has been developed.
|
|
| 20. |
- Blissing, Björn, 1978-, et al.
(författare)
-
Augmented and Mixed Reality as a tool for evaluation of Vehicle Active Safety Systems
- 2013
-
Ingår i: Proceedings of the International Conference Road Safety and Simulation. - : Aracne editrice.
-
Konferensbidrag (refereegranskat)abstract
- Even though the realism of driving simulators increases constantly, there is a potential issue with how representative the test is compared to a real life scenario. An alternative to simulators is to present a mixture of real and simulated environment to the driver and perform the scenario at a test track when driving a real vehicle. This enables an efficient way of testing that inherits many of the advantages of driving simulators as well as some of the advantages of physical testing in prototype vehicles. The present paper is a compilation of previous research in augmented reality in vehicle driving situations, focusing on technical limitations of Head-Mounted-Displays.
|
|
| 21. |
- Blissing, Björn, 1978-, et al.
(författare)
-
Driver behavior in mixed and virtual reality : a comparative study
- 2016
-
Ingår i: Proceedings of the DSC 2016 Europe. - Paris, France : Driving Simulation Association. ; , s. 179-186
-
Konferensbidrag (refereegranskat)abstract
- This paper presents a comparative study of driving behavior when using different virtual reality modes. Test subjects were exposed to mixed, virtual, and real reality using a head mounted display capable of video see-through, while performing a simple driving task. The driving behavior was quantified in steering and acceleration/deceleration activities, divided into local and global components. There was a distinct effect of wearing a head mounted display, which affected all measured variables. Results show that average speed was the most significant difference between mixed and virtual reality, while the steering behavior was consistent between modes. All subjects but one were able to successfully complete the driving task, suggesting that virtual driving could be a potential complement to driving simulators.
|
|
| 22. |
- Blissing, Björn, 1978-, et al.
(författare)
-
Driver behavior in mixed and virtual reality : A comparative study
- 2019
-
Ingår i: Transportation Research Part F. - : Elsevier. - 1369-8478 .- 1873-5517. ; 61, s. 229-237
-
Tidskriftsartikel (refereegranskat)abstract
- This paper presents a comparative study of driving behavior when using different virtual reality modes. Test subjects were exposed to mixed, virtual, and real reality using a head mounted display capable of video see-through, while performing a simple driving task. The driving behavior was quantified in steering and acceleration/deceleration activities, divided into local and global components. There was a distinct effect of wearing a head mounted display, which affected all measured variables. Results show that average speed was the most significant difference between mixed and virtual reality, while the steering behavior was consistent between modes. All subjects but one were able to successfully complete the driving task, suggesting that virtual driving could be a potential complement to driving simulators.
|
|
| 23. |
|
|
| 24. |
- Blissing, Björn, 1978-, et al.
(författare)
-
Effects of Visual Latency on Vehicle Driving Behavior
- 2016
-
Ingår i: ACM Transactions on Applied Perception. - New York, NY, USA : ACM Digital Library. - 1544-3558 .- 1544-3965. ; 14:1, s. 5:1-5:12
-
Tidskriftsartikel (refereegranskat)abstract
- Using mixed reality in vehicles provides a potential alternative to using driving simulators when studying driver-vehicle inter- action. However, virtual reality systems introduce latency in the visual system that may alter driving behavior, which, in turn, results in questionable validity. Previous studies have mainly focused on visual latency as a separate phenomenon. In this work, latency is studied from a task-dependent viewpoint to investigate how participants’ driving behavior changed with increased latency. In this study, the investigation was performed through experiments in which regular drivers were subjected to different levels of visual latency while performing a simple slalom driving task. The drivers’ performances were recorded and evaluated in both lateral and longitudinal directions along with self-assessment questionnaires regarding task performance and difficulty. All participants managed to complete the driving tasks successfully, even under high latency conditions, but were clearly affected by the increased visual latency. The results suggest that drivers compensate for longer latencies by steering more and increasing the safety margins but without reducing their speed.
|
|
| 25. |
- Blissing, Björn, 1978-, et al.
(författare)
-
Exploring the suitability of virtual reality for driving simulation
- 2018
-
Ingår i: Proceedings of the Driving Simulation Conference 2018. - Antibes, France. - 9782857827344 ; , s. 163-166, s. 163-166
-
Konferensbidrag (refereegranskat)abstract
- Head mounted displays (HMDs) is an emerging technology and the availability of affordable systems is growing fast. Replacing projector and large screen solutions with head mounted displays may appear as an appealing solution. However, inherent properties and technical limitations of these systems need to be understood and considered before making the leap to virtual reality.This paper outlines some of the most fundamental limitations of head mounted displays relevant to this context, both from a technical and human factors perspective. Desirable properties of scenarios and types of studies are deduced, based on these limitations. Finally, a meta analysis is performed on the feasibility of transferring simulator studies found in the literature to platforms with head mounted displays. The results suggest that a noticeable amount (40%) of the investigated simulator studies could likely have been performed with head mounted displays. This number could be increased further with technical advances in display resolution, display technology, reduction in latency, etc.
|
|
| 26. |
- Blissing, Björn, 1978-, et al.
(författare)
-
The Effects on Driving Behavior When Using a Head-Mounted Display in a Dynamic Driving Simulator
- 2022
-
Ingår i: ACM Transactions on Applied Perception. - : Association for Computing Machinery. - 1544-3558 .- 1544-3965. ; 19:1, s. 1-18
-
Tidskriftsartikel (refereegranskat)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.
|
|
| 27. |
- Bruzelius, Fredrik, 1974-, et al.
(författare)
-
A Basic Vehicle Dynamics Model for Driving Simulators
- 2013
-
Ingår i: International Journal of Vehicle Systems Modelling and Testing. - 1745-6436 .- 1745-6444. ; 8:4, s. 364-385
-
Tidskriftsartikel (refereegranskat)abstract
- Driving simulators are a useful research tool in studies of vehicle and transport-related human machine interface. A vital part of the driving simulator is the vehicle dynamics model. In the present paper, such a model is developed. The model implements basic first order phenomena, but is yet complete in the terms of modelled parts of the vehicle. A major challenge is the trade-off between simplicity and accuracy imposed by the capabilities of the driving simulators motion platform. The modelling language Modelica was used for readability reasons. The model has been validated toward both measurements of a real car and subjectively in a driving simulator. It is shown that the model is well capable of fulfilling the imposed requirements, despite its simplicity. The model is open and available upon request.
|
|
| 28. |
- Bruzelius, Fredrik, 1974-, et al.
(författare)
-
A simple real-time aerodynamic model for vehicles in overtaking situations
- 2013
-
Ingår i: International Journal of Vehicle Systems Modelling and Testing. - 1745-6436 .- 1745-6444. ; 8:3, s. 241-259
-
Tidskriftsartikel (refereegranskat)abstract
- Aerodynamic forces and moments play an important role inovertaking situations and affect the trajectory of the involved vehicles. One method of studying these effects and how the driver responds to these is via driving simulator studies. However, models that describe aerodynamic forces and moments are typically computationally complex and not suited for real time execution in driving simulators. The present work presents a simplified real time model of the moments and forces acting in an overtaking situation due to aerodynamic pressure imbalances. The model is compared with experimentally validated Navier-Stokes solutions. Despite the model’s simplicity, implemented as finite impulse response filters, it manages to capture the main features of the forces and moments. The approach used to derive the model is fairly general and might be used in similar applications where computational burden is a key issue.
|
|
| 29. |
- Bruzelius, Fredrik, 1974-
(författare)
-
A theoretical justification of the sine with dwell manoeuvre
- 2015
-
Ingår i: Vehicle System Dynamics. - : Informa UK Limited. - 0042-3114 .- 1744-5159. ; 53:4, s. 493-505
-
Tidskriftsartikel (refereegranskat)abstract
- The sine with dwell (SWD) manoeuvre has received much attention within the context of vehicle stability testing. This manoeuvre is used in a test developed by the NHTSA, designed to certificate electronic stability control systems in light vehicles. The test is used in legislations as well as in consumer tests all over the globe. The SWD manoeuvre was designed using test vehicles on a test track and experimentally validated. The paper at hand uses optimal control theory to theoretically justify the use of the SWD manoeuvre to produce a severe lateral motion and over-steering based on steering input. It is shown that a manoeuvre similar to the SWD manoeuvre can be obtained from an optimal control problem using simple vehicle dynamics models. The optimal control method is further used to analyse the manoeuvre's robustness with respect to vehicle dimensions and tyre properties. It is shown that the manoeuvre is robust in dimensions, which theoretically motivates its application for various sizes of vehicles.
|
|
| 30. |
|
|
| 31. |
|
|
| 32. |
|
|
| 33. |
|
|
| 34. |
- Bruzelius, Fredrik, 1974
(författare)
-
Linear Parameter-Varying Systems - an approach to gain scheduling
- 2004
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- In recent years the interest for gain scheduling methods has increased. Gain scheduling is a collection of methods that try to tackle the challenging problem of nonlinear control in a divide and conquer manner. The use of local linear system theory to obtain a non-local controller is the fundament of the gain scheduling methods. However, the local descriptions of the nonlinear system cannot capture the non-local behavior. Hence, gain scheduling methods may not result in a controller that meets the specifications of the feedback system. Introducing Linear Parameter-Varying (LPV) systems as an intermediate system description in the controller synthesis enables a systematic way of obtaining the nonlinear controller in a linear-like fashion. In this thesis, LPV systems are investigated in a gain scheduling context. The non-trivial procedure of describing a nonlinear system in the LPV form is investigated and different approaches to obtain an LPV system that is suitable for synthesis purposes are presented. Computational aspects, in terms of parameterized linear matrix inequalities, of LPV controller synthesis in an L2 gain framework is investigated. A procedure to obtain a fixed order LPV controller is presented. Finally, it is shown that a controller obtained by LPV based gain scheduling gives the expected nonlinear non-local behavior of the feedback system in a domain that is readily determined from the LPV synthesis. The consequence of the results in this thesis is that the obtained controller in closed loop meets certain specifications of the closed loop system. The synthesis can be done in a computationally tractable and systematic way. Hence, the LPV based gain scheduling approach is a worthy competitor to other controller synthesis methods for nonlinear systems.
|
|
| 35. |
- Bruzelius, Fredrik, 1974, et al.
(författare)
-
Low speed performance based standards for the Nordic countries
- 2021
-
Ingår i: International Journal of Heavy Vehicle Systems. - : Inderscience Publishers. - 1741-5152 .- 1744-232X. ; 28:1, s. 110-124
-
Tidskriftsartikel (refereegranskat)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.
|
|
| 36. |
|
|
| 37. |
|
|
| 38. |
- Bruzelius, Fredrik, 1974-, et al.
(författare)
-
Model and Road Surface Sensitivity of Longitudinal Performance Based Standards
- 2016
-
Konferensbidrag (refereegranskat)abstract
- Performance-based standards (PBS) is a regulation policy to address the complexity of variations in vehicle combinations. It enables a direct way of addressing certain requirements associated with the safety, environment and road network and their implications to the vehicle specific quantities without stipulating vehicle properties.Computer-based simulations may be an efficient tool to assess the performance measures. However, using simulations through models in a legislation raise questions of model accuracy and model complexity. What is a required level of modelling details to be used to assess a PBS measure?We investigate three level of complexity of models and the impact this have on three longitudinal performance measures; Startability, Gradeablity and Acceleration Capability. Simulations for 10 vehicle combinations are compared with two different engine alternatives. For Nordic countries, slippery road conditions are common during winter conditions. Hence, low friction is included in the comparison.The comparison suggested that the complexity could potentially be kept really low, without major loss of accuracy. However, for slippery conditions, a higher levels of complexity might be required.
|
|
| 39. |
- Bruzelius, Fredrik, 1974, et al.
(författare)
-
Model and Road Surface Sensitivity of Longitudinal Performance Based Standards
- 2016
-
Ingår i: The 14th International Symposium on Heavy Vehicle Transport Technology. ; , s. http://road-transport-technology.org//Proceedings/HVTT%2014//Bruzelius%20-%20Model%20and%20road%20surface%20sensitivity%20of%20longitudinal%20performance%20based%20standards.pdf-
-
Konferensbidrag (refereegranskat)
|
|
| 40. |
- Bruzelius, Fredrik, 1974-, et al.
(författare)
-
Realism of overtaking situations in motion based driving simulators
- 2013
-
Ingår i: Road Safety and Simulation International Conference RSS2012, October 23-25, 2013, Rome, Italy. ; , s. (1-12)
-
Konferensbidrag (refereegranskat)abstract
- The credibility of the research results of driving simulator studies is highly dependent on the realism that the simulator is capable of producing. A key component is therefore how realistic the driving is perceived by the drivers (test subjects). Overtaking is a frequently occurring traffic situation (as well as one of the highest risk manoeuvres). The aim of the present study was to enhance the perceived realism of overtaking situations in a motion-based driving simulator by introduce aerodynamic forces and moments. An earlier developed real time model of the aerodynamic forces and moments was been implemented and tested in a study with test drivers.With an appropriate scaling of the forces and torques it was shown that the perceived realism can be enhanced by the introduction of these effects.
|
|
| 41. |
|
|
| 42. |
- Bruzelius, Fredrik, 1974-, et al.
(författare)
-
The influence of tractor lengths on traffic safety and efficiency : a simulation study
- 2022
-
Rapport (övrigt vetenskapligt/konstnärligt)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.
|
|
| 43. |
- Bruzelius, Fredrik, 1974-, et al.
(författare)
-
Towards an Indoor Winter Tire Classification Test
- 2012
-
Ingår i: Proceedings of VSDIA 2012.
-
Konferensbidrag (refereegranskat)abstract
- From a traffic safety perspective it is highly motivated to define winter tires interms of their performance in icy road conditions. The present definition of winter(snow) tires, introduced in the EU in 2012, is based on packed snow performance.The present paper investigates the feasibility of an indoor winter tire classificationtest on ice. Results presented here indicates that a test procedure in an indoorhockey rink is possible, with relatively high repeatability. However, further fieldtest is required to fully establish feasibility of the procedure.
|
|
| 44. |
- Bruzelius, Fredrik, 1974-, et al.
(författare)
-
Validation of a basic combined slip tyre model for use in friction estimation applications
- 2014
-
Ingår i: Proceedings of the Institution of mechanical engineers. Part D, journal of automobile engineering. - : SAGE Publications. - 0954-4070 .- 2041-2991. ; 228:13, s. 1622-1629
-
Tidskriftsartikel (refereegranskat)abstract
- Tyre modelling is an important part of understanding and estimating the tyre-road friction. In this paper a basic steady-state tyre model for the combined-slip case is derived. The model is intended to be used in friction estimations applications, where the model complexity is of high priority. The model, described using only two parameters, is validated with measured data from various conditions and tyre types using mobile measurement equipment. The performance from the measurements suggests that only two parameters are sufficient for the combined-slip case.
|
|
| 45. |
- Bruzelius, Fredrik, 1974-, et al.
(författare)
-
Winter testing in driving simulators
- 2018
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Many traffic accidents are due to winter conditions like slippery roads and limited visibility. The road administrators put a lot of effort into snow removal and de-icing the roads, and the vehicle manufacturers have been working with functionality to support drivers in winter conditions for decades.Many issues of driving in winter conditions originate in drivers’ behaviours such as risk taking and lack of awareness. Studying drivers’ behaviour in winter conditions in general, and the effect of various countermeasures of the vehicle, would increase the understanding of the underlying mechanisms and could possibly be used to reduce the accident risks. Motion-base driving simulators are tools frequently used for driving behaviour research. However, the validity of the results of such studies depends to a large extent on the realism of the simulation. The purpose of this project was to study winter simulation with the aim to improve the realism of simulator driving in winter conditions.Driving in winter is in many ways different from driving in summer. The difference can to a considerable extent be explained by the tire-to-road interaction. Winter driving is typically characterized by softer motion and slower development of tire forces. In the present project two aspects of the motion have been studied, the motion feedback in the simulator and models for tire-to-snow behaviour.Vehicle motion during winter driving is characterized by large vehicle body slip angles and the associated yaw motions. Thus, understanding the importance of yaw motion feedback is essential to simulate winter conditions. A study was designed to investigate the impact that lack of yaw motion will have on the driver, and if it alters his driving behaviour. It was found that the yaw motion alters the driving behaviour, implying that it contains vital information for a wide range of driving situations. A second study was carried out to investigate if the rotation centre, which is a consequence of the yaw and lateral motions, can be used to present valuable information about the vehicle state to the driver. Indicative results suggest that the rotation centre of the motion is valuable to the driver, but further studies are needed. The softer and slower motions of winter driving suggest that pre-positioning of the simulator’s motion platform could be performed to improve the motion envelope. A third implementation study performed in the project suggests this.
|
|
| 46. |
- Chen, Weitao, 1989, et al.
(författare)
-
A Method to Improve Stability and Transparency for Mechanical Hardware-in-the-Loop Simulation
- 2021
-
Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- In mechanical hardware-in-the-loop (MHIL) simulation the test hardware and the simulated environment are coupled by an interface, which typically is a dynamometer rig. This interface determines the simulation accuracy and robustness. In this work, MHIL simulation is analysed in a linear robust control framework. The system consists of an inner loop formed by the load motor controller and the rig, and an outer loop formed by the test hardware and the simulated environment. While the inner loop tracking set the overall performance, instability and poor performance may be introduced by the outer loop. We demonstrate how delay tolerance of MHIL simulation varies with the outer loop dynamics. A new method is introduced to improve the robustness and accuracy. The method utilizes flexibility of the simulation model, and only software changes are needed. The proposed method is applied to an MHIL simulation for vehicle and electric power assisted steering (EPAS) system test. The effectiveness of the method is shown analytically and experimentally.
|
|
| 47. |
- Chugh, Tushar, 1989, et al.
(författare)
-
An approach to develop haptic feedback control reference for steering systems using open-loop driving manoeuvres
- 2020
-
Ingår i: Vehicle System Dynamics. - : Informa UK Limited. - 1744-5159 .- 0042-3114. ; 58:12, s. 1953-1976
-
Tidskriftsartikel (refereegranskat)abstract
- In this paper, a methodology to capture the model-based haptic feedback control reference for closed-loop steering systems is demonstrated. The parameterisation is based on the measurements of open-loop driving manoeuvres for the inertia-spring-damper-friction reference model. The steady-state and transient manoeuvres are used to identify the model parameters. The reference model is limited to the haptic feedback of driver excitation in the linear vehicle handling range and intended to be used in closed-loop steering control strategies. The model parameters have an intuitive interpretation that allows to be used in both admittance and impedance control setting. The feasibility of the proposed model is demonstrated in a validated simulation environment for electric power assisted steering and on a real hardware for the steer-by-wire force-feedback case.
|
|
| 48. |
- Chugh, Tushar, 1989, et al.
(författare)
-
Comparison of Steering Feel Control Strategies in Electric Power Assisted Steering
- 2018
-
Ingår i: International Symposium on Advanced Vehicle Control.
-
Konferensbidrag (refereegranskat)abstract
- This paper presents an objective comparison of two closed-loop steering feel control concepts in an electric power assisted steering (EPAS) system. The closed-loop methods, torque- and position-control, aim to compensate the EPAS motor inertia in an effective manner as compared to the open loop (feed-forward) solution. For a given steering feel reference, the feedback controllers are developed in a sequential manner ensuring coupled stability. Linear system theory is used for the analysis. For a comparable reference tracking and stability margin, higher haptic controller bandwidth is achieved in torque-control. The position controller stability and performance are limited due to feedback control filtering and high system inertia (from EPAS motor and driver arms), which further makes it more sensitive towards muscle co-contraction. Moreover, torque-control offers better road disturbance attenuation for low and high frequency spectrum, whereas position-control is better for mid-frequency range.
|
|
| 49. |
- Chugh, Tushar, 1989, et al.
(författare)
-
Design of Haptic Feedback Control for Steer-by-Wire
- 2018
-
Ingår i: IEEE Conference on Intelligent Transportation Systems, Proceedings, ITSC. - : Institute of Electrical and Electronics Engineers Inc.. - 9781728103235 ; 21, s. 1737-1744
-
Konferensbidrag (refereegranskat)abstract
- This paper illustrates a comparison of different haptic feedback control strategies; primarily focusing on open and closed-loop methods for a Force-Feedback Steer-by-Wire system. Due to shortcomings caused by the feedback motor impedance in the open loop architecture, the tracking performance is deteriorated. Consequently it is shown that the closed-loop solutions provide an improved response within the desired steering excitation range. The closed-loop possibilities, torque and position control, are designed and objectively compared in terms of performance and stability. The controller objectives are inertia compensation and reference tracking. For a given reference, the stability constraint between the controller gains responsible for the two objectives is contrasting in both the methods. Higher bandwidth is achieved for torque controller, whereas the driver arm inertia limits the position control performance. The linear system analysis is supported by the experimental results.
|
|
| 50. |
- Chugh, Tushar, 1989, et al.
(författare)
-
Method and apparatus for operating a haptic system
- 2020
-
Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- The present invention relates to a method for operating a haptic system, such as a vehicle electric steering system, etc. We present a real-time disturbance observer based control strategy for a desired steering feedback, ranging from virtual to realistic behavior. The invention covers both the impedance (or torque) and admittance (or position) control concepts.
|
|
