Simulation study on an acceleration control system for semi-active in-car crib with joint application of regular and inverted pendulum mechanisms

Abstract

To reduce the collision shock and risk of injury to an infant in an in-car crib (or a child safety bed) during a vehicle crash, it is necessary to limit the force acting on the crib below a certain allowable value. To realize this objective, we propose a semi-active in-car crib system with the joint application of regular and inverted pendulum mechanisms. The crib is supported by an arm similar to a pendulum, and the pendulum system itself is supported by an arm similar to an inverted pendulum. In addition, the arm acting as a regular pendulum is joined with the arm acting as an inverted pendulum through a linking mechanism, and the friction torque of the joint connecting the base and the latter arm is controlled using a brake mechanism, which enables the proposed in-car crib to gradually increase the deceleration of the crib and maintain it at around the target value. This system not only reduces the impulsive force but also transfers the force to the infant’s back using a spin control system, i.e., the impulse force is made to act perpendicularly on the crib. The spin control system was developed in our previous work. The present work focuses on the acceleration control system. A semi-active control law with acceleration feedback is introduced using a dynamic equation for the jerking of the crib. In addition, the effectiveness of the system is demonstrated using numerical software for a multibody dynamics simulation, and some of results are reported.

Keywords

• shock control
• occupant crash protection
• passive safety device
• child restraint system
• impact relaxation