Backstepping Control Design for Vehicle Active Restraint Systems

Active control of vehicle restraint systems has been extensively investigated in past decades. Many promising results have shown that a seat-belt system can be controlled in real-time to minimize human driver/occupant's injuries by reducing the human chest acceleration after a frontal impact. This paper presents a new nonlinear model that groups the seat-belt restraint system and the human driver's nonlinear high-coupling dynamics together to form a cascaded system. By using a backstepping design procedure, a global control law is developed and aimed to actively and continuously adjust the seat-belt strain force so as to interact both the human's shoulder/chest and waist. Both the control theory development and 3D graphical simulation study show that the overall system stability is well achieved. Even if up to a freeway speed, such as at 65 mph, the accelerations of the three major human body joints: lumber, thorax, and neck after a frontal collision can still be reduced significantly.