Steering Feedback in Dynamic Driving Simulators: The Influence of Steering Wheel Vibration and Vehicle Motion Frequency

TL;DR

This paper investigates how steering wheel vibration frequency content and vehicle body motion frequency content shape subjective steering-feedback evaluation in a high-fidelity driving simulator. Using a controlled back-to-back design, 27 subjects drive a reference EPS-equipped vehicle and three simulator variants, with two frequency-manipulation techniques: Rack Force Frequency Augmentation (RFFA) and Motion Cueing Algorithm (MCA). Analyses show significant effects of frequency content on Road contact and related judgments, even when stationary steering metrics appear well reproduced, indicating that existing evaluation criteria do not fully capture dynamic, road-feedback perceptions in simulators. The findings highlight the need to incorporate higher-frequency stimuli and multi-modal cues in simulator validation and steering-feel development for SbW and advanced EPS systems. Overall, the work demonstrates that frequency content in the $10$–$30$ Hz SWT band and the $10$–$50$ Hz motion content can meaningfully alter subjective assessments, suggesting avenues for extending objective and perceptual validation of driving simulators.

Abstract

The validity of the subjective evaluation of steering feedback in driving simulators is crucial for modern vehicle development. Although there are established objective steering characteristics for the assessment of both stationary and dynamic feedback behaviour, factors such as steering wheel vibrations and vehicle body motion, particularly in high-frequency ranges, present challenges in simulator fidelity. This work investigates the influence of steering wheel vibration and vehicle body motion frequency content on the subjective evaluation of steering feedback during closed-loop driving in a dynamic driving simulator. A controlled subject study with 30 participants consisting of a back-to-back comparison of a reference vehicle with an electrical power steering system and three variants of its virtual representation on a dynamic driving simulator was performed. Subjective evaluation focused on the representation of road feedback in comparison to the reference vehicle. The statistical analysis of subjective results show that there is a significant influence of the frequency content of both steering wheel torque and vehicle motion on the subjective evaluation of steering feedback in a dynamic driving simulator. The results suggest an influence of frequency content on the subjective evaluation quality of steering feedback characteristics that are not associated with the dynamic feedback behaviour in the context of established performance indicators.

Figures (7)

• Figure 1: The Advanced Vehicle Driving Simulator (aVDS) at the IFM of the Kempten University of Applied Sciences
• Figure 2: Performance of the longitudinal controller. The solid black line on the left axis represents the reference velocity profile, its 95 percent confidence interval is displayed in grey. The mint-colored lines represent the velocity profiles from all three simulator variants. The grey lines on the right axis represent the respective relative error. The displayed RMSE value is the mean over all three displayed simulator variants.
• Figure 3: Comparison of power spectral densities of SWT during closed-loop driving. The black line represents the reference drive, its 95 percent confidence interval is displayed in grey. The mint-colored lines represent the simulator variants. The solid line represents the simulator variants with active RFFA while the dotted (lower) line represents the simulator variants without RFFA.
• Figure 4: Spectrogram of measured rack forces vs. distance traveled along the reference path. \ref{['fig_AlgoPerformance_ref']} Reference vehicle, \ref{['fig_AlgoPerformance_V2']} aVDS with raw model output (V2) and \ref{['fig_AlgoPerformance_V3']} aVDS with RFAA (V1 and V3). The yellow scatters mark the dominant frequency at each STFT sample.
• Figure 5: Absolute values of BI ratings (higher value means better) for simulator variants V1 (\ref{['fig_Spider_RoadContactVar139']}), V2 (\ref{['fig_Spider_RoadContactVar239']}) and V3 (\ref{['fig_Spider_RoadContactVar339']}). The mint-colored lines represent the simulator variants while the black lines represent the reference vehicle. SWT-ON: 'SWT on-center', SWT-OFF: 'SWT off-center', SWT-G: 'SWT gradient', CF: 'Centre-feel', RC: 'Road contact', LF-RF: 'Low-frequency road feedback', HF-RF: 'High-frequency road feedback'