Development of a Simulation Model of Sit-to-Stand Movement for Design of a Power Assistance Type Handrail

Abstract

The aim of this study was the development of a computer model for simulation of sit-to-stand (STS) movement for design of a power assistance type handrail. Firstly, trajectory of the center of mass (COM) and ground reaction force during the STS movement were measured under various conditions in healthy subjects and patients with Parkinson's Disease (PD). Secondly, the ground reaction force corresponding to any speed and position of COM at seat-off (the instant lifted from the seat of a chair) was calculated from the experimental data, and a computer model simulating the trajectory of COM after seat-off from these parameters was constructed using a Telescopic Inverted-Pendulum model. As a result, the combinations of the speed and position of COM at seat-off determined whether subject could stand up. It was shown that when a position of COM was rear at seat-off subjects could stand up at a fast speed of COM and when a position of COM was front at seat-off subjects could stand up at a slow speed of COM. These results suggest that our simulation model can provide useful information to support suitable STS movement to individual using a power assistance type handrail.