1/28 Challenge the future Haptic feedback on the steering wheel to maximize front axle grip Joop van Gerwen BioMechanical Design & Precision and Microsystems Engineering, Automotive

2/28 Challenge the future Contents Introduction Methods Concept Experiments Data analysis Results Discussion

3/28 Challenge the future Introduction

4/28 Challenge the future Introduction Reduces loss of control Effect: Reduces fatal single vehicle crashes by [1] 30-50% among cars and 50-70% among SUVs Best since seat belt! Developed from ABS But: large impact on velocity Active Front Steering (AFS) ESC systems [1] S.A. Ferguson, The Effectiveness of Electronic Stability Control in Reducing Real-World Crashes: A Literature Review, 2007 [2] [3]

5/28 Challenge the future Introduction Related research on lateral vehicle dynamics guidance Lanekeeping Principle: shared control Controller is capable of controlling the system Actuator power not strong enough for full control Haptic feedback [1] J. Switkes, E. Rosetter, I. Coe, Handwheel force feedback for lanekeeping assistance: combined dynamics and stability

6/28 Challenge the future Introduction Goal : Use haptic feedback to let the driver take the corrective AFS action Guide to maximum front axle grip Idea & title explanation

7/28 Challenge the future Methods

8/28 Challenge the future Methods Concept – Controller structure Purpose: Guide the driver to the proper steering action

9/28 Challenge the future Methods Concept – Upper controller structure

10/28 Challenge the future Pacejka combined slip tire model Methods Concept – Lower controller structure

11/28 Challenge the future Methods Concept – How does it feel?

12/28 Challenge the future Methods Concept – How does it feel?

13/28 Challenge the future Methods Experiments – Vehicle

14/28 Challenge the future Methods Experiments – Tracks [1]

15/28 Challenge the future 9 drivers 2 tracks Wet skid-pad 7 runs of 35 second Task: follow inner line as fast as possible Adverse track 3 runs of 70 second (approximately 2 laps) Task: take the corners as quick as you can NASA Task Load Index 2 experiment days Methods Experiments – Procedures

16/28 Challenge the future Methods Experiments – Pictures & video

17/28 Challenge the future Methods Filtered: Driver torque and accelerations (3Hz anti-causal low pass) Removed: unwanted data Wet skid-pad RMS data Adverse track Translation of data One full, running lap isolated Analysis – Filtering & preparation

18/28 Challenge the future Methods Performance metrics Example: velocity Driving behavior metrics Example: steering wheel angle Feedback controller metrics Example: feedback torque Analysis – Metrics

19/28 Challenge the future Results

20/28 Challenge the future Results Significance Two data sets T-test to calculate chance that data sets originate from the same source Chance < 5% is significant Influence of external factors P-value = e-007

21/28 Challenge the future Results Wet skid-pad

22/28 Challenge the future Results Adverse track – Velocity

23/28 Challenge the future Results Adverse track – One corner Steering angle Yaw rate Driver torque Steering angle error Significantly lower Significantly higher

24/28 Challenge the future Results Adverse track – Road position

25/28 Challenge the future Results Variables: Mental demand Physical demand Temporal demand Performance Effort Frustration No significant changes Small test group NASA Task load index

26/28 Challenge the future Discussion

27/28 Challenge the future Discussion Room for improvements: State estimation & sensing Tire model vs. force sensing bearing Haptic feedback philosophy Desired yaw rate determination very simple Corrective yaw torque controller Possible negative stiffness of steering system Do not prevent drivers from steering back to neutral Conclusions – Improvements

28/28 Challenge the future Discussion Haptic feedback caused: Driving behavior change Vehicle eager to steer Higher driver torque Increased yaw rate Drivers were drawn to a trajectory Potential, but unsafe in current form Conclusions – Significant changes

29/28 Challenge the future