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. 

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.

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.