Optimal design of shock absorbing floor mechanism based on mechanical singularity and mechanical energy exchange

Abstract

Accidents of elderly people fall from their beds have become a problem in the nursing care field. Fencing off the bed is undesirable because it causes a sense of entrapment, and a device to mitigate the impact of a fall and protect the elderly from their injury is required. On the other hand, Passive Momentum Exchange Impact Damper (Passive MEID) has been developed to absorb the impact. It is attached to a falling object, converts the momentum from the falling object into the weight, and finally dissipates the energy by causing the weight to impact the ground. In this study, we apply this concept to design of a floor mechanism that mitigates impact. We analyze the degrees of freedom of the mechanism, show how the impact force is blocked by the singularity using kinematic analysis, and optimize the mechanism to reducing the maximum acceleration of the body element. A prototype is designed and experiments demonstrates the effectiveness of the proposed mechanism.