Musculoskeletal Driver Model for the Steering Feedback Controller

Lydia Schenk,Tushar Chugh,Fredrik Bruzelius,Barys Shyrokau

doi:10.3390/vehicles3010007

Lydia Schenk, Tushar Chugh + Show 2 more

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https://doi.org/10.3390/vehicles3010007

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Abstract

This paper aims to find a mathematical justification for the non-linear steady state steering haptic response as a function of driver arm posture. Experiments show that different arm postures, that is, same hands location on the steering wheel but at different initial steering angles, result in a change in maximum driver arm stiffness. This implies the need for different steering torque response as a function of steering angle, which is under investigation. A quasi-static musculoskeletal driver model considering elbow and shoulder joints is developed for posture analysis. The torque acting in the shoulder joint is higher than in the elbow. The relationship between the joint torque and joint angle is linear in the shoulder, whereas the non-linearity occurs in the elbow joint. The simulation results qualitatively indicate a similar pattern as compared to the experimental muscle activity results. Due to increasing muscle non-linearity at high steering angles, the arm stiffness decreases and then the hypothesis suggests that the effective steering stiffness is intentionally reduced for a consistent on-center haptic response.

Highlights

The model is limited to eight rotational degrees of freedom which result in a unique solution for every steering wheel angle, whereas the real-life human arm posture with more degrees of freedom does not result in a unique solution
The frequency response measurements show that the maximum estimated driver arm stiffness reduces with an increasing steering angular position, while keeping the same location of hands on the steering wheel
This lays the foundation of our research problem and it implies, the role of driving arm posture in creating a desired non-linear on-center steering haptic response

Summary

Introduction

The development of Advanced Driver Assistance Systems (ADAS) and Automated. The semi-automated driving (SAE Level 2 and 3), keeping the human-in-the-loop, will still dominate resulting in the further development of ADAS as well as the generation of steering systems. One of the most important cues in the driver–vehicle interaction is the haptic feedback from the steering wheel [2]. It provides the driver with a desired part of the steering feel. This steering feedback is dependent on the haptic control strategy [3,4], which further consists of various software functions.

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