The TAKATA Intelligent Total Restraint System, or ITRS, is a controllable vehicle occupant restraint system optimized so as to cost effectively minimize the risk of injury to occupants from crashes. A model based technique is described for optimizing the performance of the ITRS. The ITRS senses occupant weight, occupant position, crash severity, and seat belt usage; and in response to these sensed measurements, controls the individual firing times of a two-stage inflator. A general form of the ITRS also controls inflator module vent area, seat belt force limit, and a seat belt pretensioning. The first stage inflator is experimentally sized so as not to injure the worst case out-of-position occupant, while the combined gas generant loading of both stages is sufficient to satisfy FMVSS-208 requirements. Given the system architecture and associated fixed parameters, occupant injury and injury assessment value (IAV) measures are each modeled as a function of the input and control variables using data gathered from an occupant simulation experiment comprising combinations of occupant size, occupant position, crash severity, and air bag inflation rate. Optimal controls are found by minimizing the IAV model with respect to the system controls subject to constraints that individual injury measures be less than corresponding threshold values. (A)
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