Basic research on semi-active in-car crib with joint application of regular and inverted pendulum mechanisms (Study on the mechanism and the control system)

Abstract

To reduce the collision shock and injury risk to a baby in an in-car crib during a car crash, it is necessary to keep the force acting on the bed constant and below a certain allowable value. Toward this end, a semi-active in-car crib with joint application of regular and inverted pendulum mechanisms is proposed. This system not only reduces the impulsive force but also transfers the force to the baby's back via a spin control system, i.e., the force acts perpendicularly on the bed. The spin control system has previously been developed. In this study, an acceleration control system is developed. At first, three type of in-car crib system is introduced and compared. Next, the in-car crib with joint application of regular and inverted pendulum mechanism is described. It is supported like a pendulum by arms, and the pendulum system is supported like an inverted pendulum by arms. And, the control system, which keeps the acceleration of the bed constant and below a set value, is proposed. The acceleration on the bed is controlled by adjusting moments of the revolution joint between the base and the arm and the revolution joint between the arms. Then, its effectiveness is confirmed via numerical simulations. The proposed system gradually increases the acceleration affecting the bed and keeps it at about the set value of -25 G, when the vehicle decelerates at -30 G.

Keywords

• mechanical engineering
• motion control
• impact control
• shock control
• occupant crash protection
• passive safety device
• child restraint system
• impact relaxation
• pendulum
• inverted pendulum