Complete Vehicle Testing of Car Occupant Muscle Responses for Integrated Safety Simulation Jonas Östh, Jóna Marín Ólafsdóttir, Johan Davidsson, and Karin Brolin Division of Vehicle Safety, Applied Mechanics Chalmers University of Technology 1
Background Chalmers Active Human Body Model Project Aim: Model occupant pre-crash responses with an FE HBM. Achieved through modeling of neuromuscular control. Requires validation data in relevant test cases. 2
Volunteer Test Aims • Generate sets of validation data for ”Active HBM” • Investigate occupant kinematic and muscle responses in potential pre-crash scenarios References: Östh J, Ólafsdóttir JM, Davidsson J, Brolin K (2013) Driver Kinematic and Muscle Responses in Braking Events with Standard and Reversible Pre-tensioned Restraints: Validation Data for Human Models. Stapp Car Crash Journal 57:1–41. Ólafsdóttir JM, Östh JKH, Davidsson J, Brolin K (2013) Passenger Kinematics and Muscle Responses in Autonomous Braking Events with Standard and 3 Reversible Pre-tensioned Restraints. Proceedings of the IRCOBI Conference; Gothenburg, Sweden, pp. 602–617
Volunteers • 11 males and 9 females • No history of neck injury • Sampling criteria: M50 and F50 +/- 10 kg and +/- 10 cm 0 0 Male Female 200 90 100 45 180 M50 M50 80 M50 F50 F50 40 160 70 80 F50 35 140 Sitting Height (cm) 60 30 Height (cm) Weight (kg) 120 Age (years) 60 50 25 100 40 20 80 40 30 15 60 20 10 40 20 10 5 20 0 0 0 0 Height Weight Age Sitting Height 4
Electromyography • Surface electrodes on major muscles of upper body • Normalized with MVCs in driving posture 5
Test Cases Driver and Passenger Autobrake PT Autobrake SB Driver Brake Belt pulls 170 N 0.2 s 11 m/s 2 6
7 Test Vehicle
8 Passenger Side
Rear Seat… 9
”Test Track” 10
11 Driver Brake Autobrake SB Autobrake PT
12 6 Autobrake PT Autobrake SB
13 Head Displacements: Drivers Female Driver Brake * p<0.05 > * Autobrake PT2–4 Autobrake SB Male In steady-state braking (1.5–1.7s) 200 180 160 140 120 100 80 60 40 20 0 Head X displacement (mm)
Shoulder Belt and Steering Wheel Forces: Drivers 14 Driver Brake Autobrake SB Autobrake PT
15 Muscle Responses: Drivers Autobrake SB Autobrake PT Driver Brake
Model Validation Autonomous Braking (SB) Driver Braking References: Östh J, Eliasson E, Happee R, Brolin K (2014) A Method to Model Anticipatory Postural Control in Driver Braking Events. Gait and Posture 40(4):664–669. 16 Östh J, Brolin K, Bråse D (2014) A Human Body Model with Active Muscles for Simulation of Pre-Tensioned Restraints in Autonomous Braking Interventions. Traffic Injury Prevention , 16(3):304–313.
Conclusions • Seat-belt pre-tension affects occupant postural responses – Pre-tension induces startle response in some volunteers • Driver Brake postural responses are different from postural response to Autobrake • Low muscle activations in normal driving (<5% for most muscles) • Co-contraction of antagonist muscles in steady state braking 17
Future work • Extend AHBM to cover lateral (steering) emergency avoidance maneuvers • Conduct new volunteer for validation data and investigation of postural control in these events • Challenges – Repeatability of steering maneuvers with non professional drivers – Effect of external threat (crash risk) – Large test matrix (many combinations, pre-tensed belt, combined with braking) 18
Acknowledgements Project partners Autoliv Research, Volvo Group, Volvo Cars, and Umeå University Funding VINNOVA – Swedish Governmental Agency for Innovation Systems, through the FFI – Vehicle and Traffic Safety research program 19
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