Precrash Dipping Nose (PCDN) Needs Pedestrian Recognition

This paper investigates the effect of vehicle front height lowering operation of precrash dipping nose (PCDN) on pedestrians. Although PCDN was developed for vehicle-vehicle side crashes, there is a possibility that the range sensor for crash detection will fail to distinguish a group of pedestrians from a side-faced vehicle. For simulation-based investigation, a vehicle model, an air spring with PCDN actuator, a pedestrian, and active hood system (AHS) were modeled. Two vehicle models were made for a sedan and a sport utility vehicle (SUV), respectively. In all crash situations (frontal crash without AHS, frontal crash with AHS, and side crash without AHS), a falsely operated PCDN is expected to cause worse pedestrian injury. As a conclusion, we insist that PCDN should incorporate a pedestrian-recognition capability into its crash detection system to reduce the improper activation of its actuator. In addition, as AHS showed a good performance even in improper activation, we propose a complementary method that activates AHS when PCDN is activated. It is noteworthy that the increasing importance of pedestrian protection seems to enforce even a system developed for vehicle-vehicle crashes to be investigated from the perspective of pedestrian safety.