Analysis of Variable Sit-to-Stand Assist Chair

This chapter delves into the critical importance of sit-to-stand (STS) movement in daily living, particularly for the elderly and individuals with mobility issues. It explores the biomechanics of STS, dividing it into four distinct phases and highlighting the challenges faced during these transitions. The chapter introduces a novel design for a variable STS assist chair that utilizes a first-class lever mechanism to provide flexible support during STS movements. The design aims to address the dependency on armrests for weight-bearing and includes a detailed description of the chair's components and functionality. The chapter also presents an ergonomic analysis of the chair, involving simulation exercises and experiments with participants of varying heights. The results indicate that the chair's design significantly assists users during STS movements, with the comfort level varying based on the position of the fulcrum point and the use of a lumbar restraint device. The analysis of knee and pelvis angles provides insights into the chair's effectiveness and user comfort, highlighting the potential benefits for individuals with disabilities, the elderly, and the general population.