Modeling of Occupant Kinematic Response in Pre-crash Maneuvers A simplified human 3D-model for simulation of occupant kinematics in maneuvers - A simplified human 3D-model for simulation of occupant kinematics in maneuvers

Abstract

Most car manufacturers today equip their cars with collision avoidance systems which can act to avoid or mitigate a crash. Retrospective studies have shown that these systems help reduce the number of crashes, however the intervening evasive maneuvers provoke occupant displacements. Consequently the occupant’s position relative to the restraint systems of the car is affected. Therefore, there is a need to investigate occupant safety also for the pre-crash phase when these evasive maneuvers take place. There are an extensive number of maneuvers to consider and the existing methods for simulating the occupant during the pre-crash phase are inefficient with respect to time. For that reason, a more efficient dynamic model of the occupant was developed to primarily compute the head kinematics and secondarily T1 kinematics, when the occupant model is subjected to the linear- and rotational accelerations that are induced by evasive maneuvers. The model represents the upper body of an occupant, i.e. a front seat passenger or a driver, which is restrained by the seat, the seat belt, as well as the arms if the model is a driver. Two types of occupant models were proposed based on the inverted spherical pendulum theory. The systems of differential equations were derived using Lagrangian mechanics and implemented in Simulink. The models were tuned and validated based on pre-existing volunteer data from vehicle maneuver studies. The results demonstrate that the models were able to capture the occupant kinematics by showing similar dynamic behavior to the kinematics of test subjects in volunteer tests. The computation time when simulating a maneuver of approximately 4 seconds, resulted in a computation time of 0.7 seconds for both models, which allows for efficient computation of an extensive number of pre-crash maneuver simulations for analysis of occupant kinematics.