| Due to the difference in characteristics of physiological anatomy between childand adult occupant, occupant restraint system which designed for adults could notprovide effective protection for children, and might even cause the child occupantsinjured or killed in the motor vehicle crashes (MVCs). Child restraint system caneffectively reduce the probability of serious injury and death of children in MVCs.However, it is difficult for parents to select correct child restraint system because ofthe rapid growth and development of children. According to field data, the misuse rateof child restraint system for children over3years of age was all above50%in theUnited States, Canada, Australia, Japan and Europe. Therefore, how to cope with themismatching problem between child restraint system and child anthropometry hasbecome a hot issue in the field of vehicle safety. Considering the above problems, thefollowing three works have been done.In this study, an integrated child seat with continuous height adjust system wasused to study the effect of child restraint system parameters on the injury of childoccupants, and an improvement research for the integrated child seat was conducted.The results shown that seat height, seatbelt limit force value and bac krest angle had thegreatest effect on child injury. The length and angle of the cushion had little effect onchild injury, but had a great effect on the injury of child abdomen. The integrated childseat can provide better protection for child occupant’s head and chest and worseprotection for child occupant’s abdomen when move side armrest lower ward and movethe seatbelt’s lower fixed point from adult seat to the child seat under both the frontcollision and the side collision.The application necessity of the approximation method and multi-objectiveoptimization for design of child occupant restraint system was studied. Polynomialregression model and multi-objective evolutionary algorithm NSGA-Ⅱ were adoptedto optimize the parameters of the integrated child safety for protecting the3,6and10year-old child occupant. The seat height, seatback angle and limit force value of seatbelt were selected as optimization parameters, and the head injury, chest injury andneck injury were selected as optimization goals. Three sets of optimized parameters ofchild restraint system were obtained which ignoring the interaction between childrenphysical characteristics and restraint parameters. And then, a new matching criterionwas presented, which determine the seat height by child occupant height, limit force value of seat belt by child occupant weight, and seatback angle by child age. Theresults shown that multi-objective optimization can provide many optimal solutions forresearcher avoiding the child occupant injury criterion which was difficult to determine.The result of multi-objective optimization was validated by simulation test, and thenew matching criterion can solve the matching problem between child restraint systemand child occupant with different anthropometry.A regulation about integrated child seat was proposed according to thecharacteristics of the integrated child seat after studying domestic and foreignregulations about vehicle seat. According to the regulation, front and rear collisiontest were conducted for the integrated child seat designed by our project team. Severalreasonable improvements were proposed for the regulation and integrated childrestraint system based on the analysis of the test results. |
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