Development of a piggyback-type transfer assist system to assist caregivers with patients being unable to move themselves

Abstract

In this study, a transfer assist system for patients who are unable to move themselves was proposed for transferring them conveniently and comfortably among bed, wheelchair, and toilet bowl. The system that applies piggybacking as the transfer method was developed via kinematics that shows the interaction between humans and machines, biomechanical analysis, and Finite element analysis (FEA). To develop a system that uses a piggybacking method, a mobile-lift structure with an actuator module that supplies the least force required to have a piggybacking effect and to lift and support body-weight loads was designed by analyzing the characteristics of piggybacking persons. A mechanical design that can be worn rapidly (within 1 min) was applied, and an upper-body support cushion and thigh- and backattached pads with a structure that supports and distributes a body-weight load uniformly while piggybacking using the system were developed. Stresses between human bodies and the machine depending on the upper-body bending angle in the piggybacking motion were analyzed through FEA and biomechanical simulation, thereby determining the stable attachment position of the attachment pads that can distribute loads uniformly and give the least body pressure to humans. This study provided an experiment to verify the comfort and reliability of the system that applies piggybacking and to minimize the pain caused by the pressure of the device from a patient’s viewpoint. The system also reduces the physical burden of caregivers with the mechanical convenience. This convenience is achieved by providing a series of processes that allow transfer patients from bed to the system and to toilet bowl rapidly without difficulty for the caregivers.