Female kinematics and muscle responses in lane change and lane change with braking maneuvers

Abstract

Objective

The primary aim of this article is to extensively study female occupant kinematics and muscle activations in vehicle maneuvers potentially occurring in precrash situations and with different seat belt configurations. The secondary aim is to provide validation data for active human body models (AHBMs) of female occupants in representative precrash loading situations.

Methods

Front seat female passengers wearing a 3-point seat belt, with either standard or pre-pretensioning functionality, were subjected to multiple autonomously carried-out lane change and lane change with braking maneuvers while traveling at 73 km/h. This article quantifies the head center of gravity and T1 vertebra body (T1) linear and rotational displacements. This article also includes surface electromyography (EMG) data collected from 38 muscles in the neck, torso, and upper and lower extremities, all normalized by maximum voluntary contraction (MVC). The raw EMG data were filtered, rectified, and smoothed. Separate Wilcoxon signed-rank tests were performed on EMG onset and amplitude as well as peak displacements of head and T1 considering 2 paired samples with the belt configuration as an independent variable.

Results

Significantly smaller lateral and forward displacements for head and T1 were found with the pre-pretensioner belt versus the standard belt (P < .05). Averaged muscle activity, mainly in the neck, lumbar extensor, and abdominal muscles, increased up to 16% MVC immediately after the vehicle accelerated in the lateral direction. Muscles in the right and left sides of the body displayed differences in activation time and amplitude relative to the vehicle’s lateral motion. For specific muscles, lane changes with the pre-pretensioner belt resulted in earlier muscle activation onsets and significantly smaller activation amplitudes compared to the standard belt (P < .05).

Conclusions

The presented results from female passengers complement the previously published results from male passengers subjected to the same loading scenarios. The data provided in this article can be used for validation of AHBMs of female occupants in both sagittal and lateral loading scenarios potentially occurring prior to a crash. Additionally, our results show that a pre-pretensioner belt decreases muscle activation onset and amplitude as well as forward and lateral displacements of head and T1 compared to a standard belt, confirming previously published results.

Keywords:

• Body kinematics
• EMG
• human body model
• lane change
• pretensioner belt
• volunteer

Acknowledgment

The authors thank all participants in the tests and our project partners at Autoliv Research and Volvo Cars. The work was carried out at SAFER - Vehicle and Traffic Safety Centre at Chalmers, Gothenburg, Sweden.

Additional information

Funding

The study was carried out by Chalmers University of Technology, Autoliv Research and Volvo Cars in the project Active human body models for virtual occupant response, step 3. The study was funded by FFI-Strategic Vehicle Research and Innovation by Vinnova, the Swedish Energy Agency, the Swedish Transport Administration, and the Swedish vehicle industry. Data analysis was also funded by the European Union Horizon 2020 Research and Innovation programme project, Future Occupant Safety for Crashes in Cars, OSCCAR, under Grant Agreement No 768947. The content of this publication does not reflect the official opinion of the European Union. Responsibility for the information and views expressed therein lies entirely with the authors.