Prediction of Pre-impact Occupant Kinematic Behavior Based on the Muscle Activity during Frontal Collision

The objective of this study is to predict the behaviors of the human body in pre-crash conditions based on the experiment with active human models. In order to simulate the actual pre-crash condition of a car that occurs when the drivers brakes or pre-crash safety system activates in an emergency situation, low speed front impact tests on human volunteers were conducted using a sled-mounted rigid seat, on which each subject sat, sliding backwards on the rails. It was observed that when the subject’s muscles were initially relaxed, muscle responses started activation at around 100ms after the onset of acceleration and reached its maximum value at around 200ms. During this time period, most of the individual body region acceleration responses and restraint system reaction forces also peaked. Furthermore, the head-neck-torso kinematics was strongly influenced by the muscle activity. This experiment indicates that muscles can react quickly enough to control the driver’s behavior significantly during the low-speed impact, relating to the driver’s posture just before the collision. Thus, the active human model with the Hill-type multi-bar muscle was employed to estimate the possible driving posture in an emergency. From the result of this experiment, preand postcrash occupant behavior was predicted. For a more detailed understating, a parametric study was conducted that distinguishes the factors presented in real accident cases.