Control system for semi-active in-car crib with joint application of regular and inverted pendulum mechanisms

Abstract

To reduce the collision shock and injury risk to an infant in an in-car crib (or in a child safety bed) during a car crash, it is necessary to keep the force acting on the crib constant and below a certain allowable value. To this end, we propose a semi-active in-car crib with joint application of regular and inverted pendulum mechanisms. The crib is supported like a pendulum by arms, and the pendulum system is supported like an inverted pendulum by arms. 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 force acts perpendicularly on the crib. The spin control system was developed previously. In the present study, an acceleration control system is developed. One of the characteristics is that this system has the merits of both a regular pendulum-style in-car crib and an inverted pendulum-style in-car crib. The regular pendulum-style one is suitable when moderate impulsive forces are involved because the crib moves smoothly soon after the force begins to affect the crib. The inverted pendulum-style one is suitable when large impulsive forces are involved because the arm that is initially tilted backward, which constitutes the inverted pendulum, is difficult to move under weak forces. Therefore, the proposed in-car crib is able to increase the acceleration of the crib gradually and maintain it around the target value. This paper focuses on the control system. The control law is introduced, and the robustness is examined using numerical simulation.

Keywords

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