Restraint Force Optimization for a Smart Restraint System

A study was conducted utilizing both math modeling and dynamic barrier simulations studying restraint system optimization for an adaptive restraint system. An adaptive restraint system is one which can adjust its characteristics based on some knowledge of the crash environment such as occupant size, crash severity, and occupant position. The restraint system characteristic can be optimized based on a constant force restraint system, that is a restraint system which provides a constant restraint force for the occupant over the entire range of occupant motion. Such a system normally results in a minimization of peak restraint forces as well as peak chest accelerations and maximum chest compression. Constant force restraint systems are normally achieved through high output pretensioning, initially stiff belt systems, load limited torso belts, and a carefully tuned airbag inflation and venting characteristic. The optimization of the constant force system is achieved through varying the load limit for the torso belt and the venting characteristic of the airbag for the normally seated occupant A range of environments was studied; 5%ile female to 95%ile male, severity of collision from delta-v =19.2 KPH to 56 KPH, and seated position from full rear to full fore. A range of torso belt load limits and airbag venting characteristics were identified to optimize occupant response over these ranges of variables.