Acceleration and spin control system for in-car crib with joint application of regular and inverted pendulum mechanisms

Abstract

To reduce collision shock and injury risk to an infant in an in-car crib (or in a child safety bed) during a car crash, the force acting on the crib must remain constant below a certain allowable value. Hence, we propose a semi-active in-car crib with joint application of regular and inverted pendulum mechanisms. The crib is supported by arms, like a pendulum; and the pendulum system is supported by arms, like an inverted pendulum. The friction torques of the joints are semi-active controlled using a brake mechanism, which enable the proposed in-car crib to gradually increase the deceleration of the crib and maintain it at approximately the target value, i.e., the large collision force is reduced to the target value. However, a collision impact is directed toward the infant’s side in the crib, and the resulting motion of the body is relatively complex. Therefore, the proposed in-car crib is designed to not only reduce the impulsive force, but also to transfer the force to the infant’s back using a spin control system, i.e., the impulse force acts perpendicularly on the crib. In this study, the spin control system of the crib is derived and applied to the acceleration control system reducing the impulse force. The objective of the spin control system is to suppress the acceleration parallel to the crib floor by rotating the crib. Finally, the effectiveness of the proposed system is demonstrated using numerical simulations.