Child-Sized Passive Exoskeleton for Supporting Voluntary Sitting and Standing Motions

This paper describes a novel passive exoskeleton for voluntary sitting-standing posture transition for children with lower limb impairment. The design of the exoskeleton is based on the utilization of the center of gravity transition through the user's upper body motion. The passive exoskeleton powered by gas springs allows the user to realize a natural-like posture transition by the user's voluntary upper body motion. We designed the posture transition model such that the user can realize the posture transition in a natural manner based on a minimum jerk criterion. The proposed design aims to permit toilet usage without transferring seating positions between the exoskeleton and toilet seat. Furthermore, the developed mechanism can be integrated with a regular wheelchair, which would allow users to have locomotion capability. We believe that the design can improve children's self-reliant social activities by supporting their voluntary posture transition and toilet use. In this paper, we describe the detailed design process of the exoskeleton and preliminary experiments to investigate its effectiveness through evaluation with a healthy participant.