Abstract
This paper presents control system design for occupant lower extremity protection in the event of a frontal car crash. A semi-active knee bolster is used to protect occupant lower extremities. The semi-active knee bolster varies the damping coefficient of the knee bolster. The control system design of the semi-active knee bolster is based on a design method of an active knee bolster. LQI (Linear Quadratic Integration) control with an initial value compensation input is applied. We obtain an optimal reference signal of the contact force between the knees and the instrument panel by considering characteristics of the semi-active actuator and the closed loop control system. The control system of the semi-active knee bolster follows the reference signal of the contact force. The protective control system with the semi-active knee bolster is effective for reducing the femur load, verified by carrying out simulations.
