Subjective vehicle stability evaluation is generally conducted during closed-loop driving in which the driver controls the vehicle through transient manoeuvres and evaluate how the vehicle responds to steering inputs, especially how the slip angle builds up. To conduct such evaluation in moving base, driving simulators require that the fed vehicle response to steering inputs is representative. Limited simulator workspace often requires motion scaling, introducing errors in planar dynamics This work, therefore, investigates how the scaling of the planar motion and the slip filtering should be performed in a driving simulator, including the relative relationships between lateral acceleration, yaw rate and slip rate. Two strategies were developed based on the scaling of planar circular motion: one retaining radius information, and the other retaining velocity information. Both strategies avoided filtering the slip rate, as simulations show that the slip rate should be separated from the high-pass filtering process in cueing algorithms and that the scaling should be equal to that of the yaw rate to avoid false cues. A subjective assessment was conducted, and the results indicate advantages for retaining radius information and conclusively the advantage of unfiltered slip information in motion cueing for stability evaluation.

Driving simulators are increasingly important in vehicle development, benefiting from hardware and motion cueing algorithm (MCA) advancements. However, current state-of-the-art MCAs are optimising with regards to a vehicle fixed vestibular system, ignoring active and passive head movements during manoeuvres. Research shows that drivers actively move their heads to focus their gaze and passively stabilising it during involuntary trunk movements, resulting in significant differences between vehicle and head yaw angles. Humans isolate trunk and head movement in the range of 0.1–1.0 Hz, suggesting neck-driven gaze stabilisation. This behaviour is not accounted for in current MCAs, warranting an investigation. This study develops a driver gaze model to enhance motion cueing strategies and compares it to existing methods. Findings indicate significant discrepancies between vehicle and estimated head yaw rate in winter testing with high slip angles, and that omitting vestibular models and separating the slip angle in the yaw feedback improves the motion cueing with regards to induced head movements. Further, the results shows that there is a clear relationship between motion cueing, visual feedback, and induced driver head movement. In conclusion, driver gaze models can improve motion cueing strategies in driving simulators, and thus the study highlights the need for considering driver gaze behaviour and provides insights for tuning and optimising MCAs.

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 subjective evaluation is to use moving base driving simulators. The motion cueing algorithms (MCA) maps the movement of the vehicle into the limited space of the simulator. The choice of reference point, that is, where on the vehicle to sample the motion to feed to the MCA and the alignment of the axis of rotation of the simulator cabin is still an open topic. This paper investigates the choice of reference point and corresponding simulator longitudinal axis of rotation in roll using two methods. The first method uses a linearised model of the combined system of vehicle, simulator and vestibular models. The second method, to position the cabin longitudinal axis of rotation, is based on offline optimisation. The linear model can capture important characteristics of the specific forces and rotations that are fed to the driver through the motion cueing algorithms and offers a method to objectively analyse and potentially tune the motion cueing. The analysis is further complemented with a subjective evaluation of corresponding settings. The results from the linear model, the offline optimisation and the subjective evaluation shows that a reference point at the driver’s head has a clear advantage over the full frequency range compared to a reference point in the chassis roll axis and that the positioning of the cabin longitudinal axis of rotation has a significant effect on the perceived vehicle characteristics.

Vehicle manufacturers strive for an increasingly efficient and faster development process. Although computer-aided engineering has made significant progress toward a fully virtual development process, a challenge remains in integrating human subjective feedback to fully close the virtual development loop. Subjective assessment of ride and driving characteristics are still very important traits of a passenger car. Moving-base driving simulators have the ability to introduce the human into the virtual development loop, thus enabling subjective assessment of virtual vehicle models. Such an introduction has the potential to significantly speed up the development process and at the same time save resources by avoiding physical testing and providing informed decisions in the early phase of vehicle development cycles. The challenge to do so lies in the possibility to evaluate a vehicle in a driving simulator, which is highly dependent on the motion cueing.

Motion cueing algorithms are used to map the vehicle motion into the confined workspace of a driving simulator. As of today, these algorithms are still often tuned and evaluated subjectively. The challenge with this approach is that it does not guarantee the fidelity of the cueing and it needs physical vehicles to be compared with. This work thus focuses on the objective development and evaluation of motion cueing, which potentially could enable high fidelity motion cueing in the early stages of the vehicle development process, when prototypes are not available. This is very important for winter testing since the testing is challenging with regards to ambient conditions, the limited testing season and the increasing need to speed up the development process.

The goal of this work is to move towards an objective approach to cueing evaluation based on physical models combining vehicle model, simulator, and human. Therefore, this thesis presents an objective methodology to motion cueing evaluation and development. Based on the state-of-the-art review, this work addresses the need for simple linear models to evaluate the fidelity of motion cueing algorithms. The linear model is applied to the problem of positioning the longitudinal axis of rotation of the simulator cabin and shows promising results when compared to time series-based optimisation and subjective assessment. Furthermore, using the same model to improve the motion cueing by introducing tilt coordination shows that even though the immersion is improved, the tilt coordination changes the perceived vehicle characteristics. To objectively evaluate different yaw cueing strategies in winter conditions, a more detailed human model is introduced that extends the state-of-the-art vestibular organ models by introducing gaze stabilisation using a model of the vestibulo-collic reflex. The cueing evaluation indicates the potential of separating slip angle feedback from the high-pass filtering of motion cues, as well as the advantage of using the vehicle’s motion as a target for cueing optimisation rather than the human vestibular response in winter handling evaluation.

By addressing the inherent skewing of vehicle characteristics in motion cueing and suggesting improvements to the evaluation and cueing strategies, this work contributes to the possibility of virtually evaluating the vehicle dynamic characteristics in driving simulators under winter conditions.

Driving feedback is an important factor that can affect the perceptions of remote drivers of the surrounding environment during teleoperation. This paper focuses on investigating the influence of motion-cueing, sound and vibration feedback on driving behaviour and experience. A prototype teleoperation station is developed with feedback from audio, vibration actuators, and motion cues. Using this prototype, the experiment is carried out in two scenarios: a low-speed disturbance scenario with 30 participants and a dynamic driving scenario with 22 participants. Objective and subjective assessment methods are used to evaluate driving behaviour and experience separately. The results indicate that the combination of motion-cueing, sound and vibration feedback provides the most favourable driving experience for the participants. Specifically, sound and vibration feedback enhance drivers' sense of speed, while motion-cueing feedback helps in road surface sensing, leading to increased throttle reversal rate in the low-speed disturbance scenario. However, it is noteworthy that motion-cueing feedback does not significantly improve driving performance in the dynamic driving scenario of this study.

Driving simulators are increasingly important in vehicle development, benefiting from hardware and motion cueing algorithm (MCA) advancements. However, current state-of-the-art MCAs are optimising with regards to a vehicle fixed vestibular system, ignoring active and passive head movements during manoeuvres. Research shows that drivers actively move their heads to focus their gaze and passively stabilising it during involuntary trunk movements, resulting in significant differences between vehicle and head yaw angles. Humans isolate trunk and head movement in the range of 0.1-1.0 Hz, suggesting neck-driven gaze stabilisation. This behaviour is not accounted for in current MCAs, warranting an investigation. This study develops a driver gaze model to enhance motion cueing strategies and compares it to existing methods. Findings indicate significant discrepancies between vehicle and estimated head yaw rate in winter testing with high slip angles, and that omitting vestibular models and separating the slip angle in the yaw feedback improves the motion cueing with regards to induced head movements. Further, the results shows that there is a clear relationship between motion cueing, visual feedback, and induced driver head movement. In conclusion, driver gaze models can improve motion cueing strategies in driving simulators, and thus the study highlights the need for considering driver gaze behaviour and provides insights for tuning and optimising MCAs.

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 investigation, which shows an increased spectral density of low frequency content in both yaw rate and lateral acceleration, coordinated tilt is added to the motion cueing, to give the driver low frequency lateral acceleration feedback. The tilt coordination filter is tuned using offline optimisation based on logged data. The resulting MCA is evaluated objectively using a linear model of a driving simulator and subjectively through driving around a winter test track with six test drivers. The test is conducted using a pairwise comparison of two different settings, one setting without and another with added tilt coordination. Objective metrics shows reduction in lateral false cues, increased correlation between actual vehicle acceleration and simulator acceleration and an increased spectral density below 0.30 Hz. The pairwise comparison and the commentary feedback shows potential in adding tilt coordination with more drivers favouring tilt coordination, however statistical significance cannot be reached due to the low number of drivers.

This paper presents a method to minimise false cues and reduce phase lag by positioning the roll axis objectively based on offline optimisation. It shows that a nonfiltered roll feedback signal could be used to reduce phase lag in the simulator and the subjective assessments indicate that the reduction of phase lag and false cues could improve the perceived fidelity of the simulator.

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 subjective evaluation is to use moving base driving simulators. The motion cueing algorithms (MCA) maps the movement of the vehicle into the limited space of the simulator. The choice of reference point, i.e., where on the vehicle to sample the motion to feed to the MCA and the alignment of the axis of rotation of the simulator cabin is still an open topic. This paper investigates the choice of reference point and corresponding simulator longitudinal axis of rotation in roll using two methods. The first method uses a linearised model of the combined system of vehicle, simulator, and vestibular models. The second method, to position the cabin longitudinal axis of rotation, is based on offline optimisation. The linear model can capture important characteristics of the specific forces and rotations that are fed to the driver through the motion cueing algorithms and offers a method to objectively analyse and potentially tune the motion cueing. The analysis is further complemented with a subjective evaluation of corresponding settings. The results from the linear model, the offline optimisation and the subjective evaluation shows that a reference point at the driver’s head has a clear advantage over the full frequency range compared to a reference point in the chassis roll axis and that the positioning of the cabin longitudinal axis of rotation has a significant effect on the perceived vehicle characteristics.