Safety of active pre-collision seat rotation strategies for autonomous vehicles: injury risk evaluation of occupant’s neck

Abstract

The development of autonomous driving technology has engendered new requirements for the safety of the occupants of autonomous vehicles. Different variants of seat configurations, including face-to-face rides and rotating seats, have been implemented in autonomous vehicles. Furthermore, pre-collision active seat rotation strategies have been proposed for the safety of the occupants of autonomous vehicles. However, further evaluations are required to determine whether the active seat rotation strategy could cause injuries to the occupants during a significantly rapid rotation process. In this study, two types of multi-rigid body seat-occupant models and a finite element model of the occupant’s cervical spine were designed. The validity of the multi-rigid body model for the seat occupant was verified through a frontal collision simulation test. Considering the influence of different seat types and rotation directions on the risk of neck injuries to the occupants, four simulations were conducted based on the condition that the seat rotated by 90° in 200 ms. The kinematic and biomechanical aspects of the risk of injuries to the occupant’s cervical spine during the active seat rotation strategy were assessed, and the essential causes of these injuries were discussed. The results indicate that, in the absence of leg baffles and foot supports, seat rotation toward the diagonal line of the seatbelt poses different degrees of risk of injuries to the cervical spine, platysma, sternocleidomastoid, common carotid artery, external jugular vein, and internal jugular vein. Therefore, the seats of highly or fully autonomous vehicles should be designed to prevent this scenario.