Influence of steering column friction on steering feel

Influence of steering column friction on steering feel: A simulator study

Skarżyńska, Marta (TU Delft Mechanical, Maritime and Materials Engineering)

Shyrokau, B. (mentor)
de Winter, J.C.F. (mentor)

Delft University of Technology

Mechanical Engineering | Biomechanical Design - BioRobotics

2018-05-07

Steering feel is an important variable that contributes to drivers’ assessment of safety and comfort. As such, creating acceptable steering feel is one of the goals of automotive manufacturers. Prediction of subjective steering feel based on objective measures, for example, driver torque characteristics, can benefit the automotive industry by decreasing time and cost of the vehicle design process.

This thesis project examined the effect of steering column friction, a sole objective parameter, on subjective steering feel and on the drivers’ performance. A driving simulator study was conducted with 17 non-professional drivers, who drove and assessed 11 dimensions of steering feel for five steering configurations. The experiment was carried out in a fixed base driving simulator. The steering configurations differed only in the level of column friction: 0 Nm, 0.15 Nm, 0.27 Nm, 0.39 Nm, 0.50 Nm. The driving task was divided into two sections: Drive on a highway without prescribed manoeuvres to evaluate the steering feel and lane following to collect objective measurements.

Data collected during the experiment were tested with Friedman’s ANOVA. The results showed that the subjective assessments of the group were influenced by the level of friction. A more pronounced effect occurred between configurations with the lowest (0 Nm, 0.15 Nm) and the highest (0.50 Nm, 0.39 Nm) steering friction. Statistically significant differences were primarily found for the dimensions steering effort, steering effort in the neutral area, centering, and reluctant feel. Drivers assessed reluctant feel as increasing and returnability as decreasing with steering friction.

In term’s of drivers’ performance, a higher workload was observed with an increase in steering friction, as measured by steering reversal rate. The same effect is present in another measure of workload, standard deviation of steering angle (STS; corrective movements become larger with friction). Lane keeping performance was not significantly affected by column friction in the present study.

In summary, the results of the present study indicate that column friction is an important factor influencing a driver’s subjective steering feel, especially for configurations with at least 0.27 Nm. The findings suggest that friction can be tuned according to the driver’s preferences without incurring a decrease in performance. The potential effect of steering friction on drivers’ safety needs further study.

steering feel
driving simulator
subjective assessment
on-centre handling

http://resolver.tudelft.nl/uuid:0e486fe0-37e1-4845-9256-1b258b84e085

Student theses

master thesis

© 2018 Marta Skarżyńska