Analysis And Optimization Of Active Control Retractor In The Rear-end Collision

Rear-end collision is a common type of traffic accident.The occupant's Out OfPosition?OOP?caused by AEBS before the rear-end collision will increase the whiplash of the occupant.Active Control Retractor?ACR?is an advanced restraint system device that can better improve the degree of OOP.The foreign research on ACR is mainly about analyzing the damage of the occupants in frontal collisions by the Autonomous Emergency Braking System?AEBS?.There are few domestic studies and literature on the impact of ACR on occupant whiplash in rear-end collisions.Thus,in this paper,the influence of the ACR key parameters on the occupant's position in the pre-collision and injury in the rear-end collision is analyzed by applying the active and passive safety simulation technology.1?Building the accident scenarios.Based on the actual traffic accident case,the scenarios of autonomous emergency braking and rear-end collision are simulated in PreScan and Ls-DYNA.Brake acceleration,pitch angle curves,and collision acceleration are provided for subsequent studies.2?Restraint system model building and validation.Taking Toyota Yaris as the target model,MADYMO7.7 was used to build the front passenger side restraint system model,including the active control retractor model,the active human model?AHM?and the vehicle body model.Based on the volunteer test and the whipping test of C-NCAP 2018,the effectiveness of the occupant restraint system model in the braking phase and the rear-end collision phase was verified.The results show that the displacement curve and the force curve of the dummy in the simulation are consistent with the corresponding curve trend in the test,which proves that the model is effective and can be used for subsequent research.3?Single factor analysis.The braking force of the AEB system,the Time To Collision?TTC?of ACR and the pre-tension force are taken as single factor variables to analyze the influence of different braking intensity on the protective effect of ACR and the effect of different TTC and pre-tension force on the occupant's position in the pre-crash phase and the injury in the rear-end collision phase.At the same time,the protective effect of ACR on the different dummies is compared and analyzed.4?Parameter matching optimization under multi-factor synergy.With pre-tension force,TTC,headrest stiffness,and back-to-seatback gap as design variables,and with the injury index,N_ij as the optimization target,the occupant restraint system is optimized by using Latin hypercube experimental design,Kriging approximation model and NSGA II in Isight.According to the above research,the ACR can effectively improve the degree of occupant OOP caused by AEB,thereby reducing the whiplash of the occupant in the rear-end collision;When the braking strength is large,the protective effect of the ACR is better.Well,the injury index,NIC is reduced by 40.67%;When the TTC is before 0s,the ACR has better protection effect,the injury index,NIC is reduced by 60%;The more pre-tension force is increased,the more obvious the protection effect is,and the injury index,NIC is reduced by 66%;the protective effect of the ACR on the active human model is better than Bio-RID dummy;The minimum N_ij during the single factor analysis is reduced by 1.531%through the parameter matching optimization.