On the comfortableness of muscle power assistive robotic system

This study provides a guideline for determining how much torque is appropriate to be added for impaired or elderly people to feel comfortable when being assisted by power assistive systems. To find out the appropriate assist level, the first experiment was designed to observe if a certain level of assist exists which people prefer, while performing goal-reaching tasks. The second experiment was established to investigate the dominant factors that make people comfortable. Based on these observations, we found that there exists a region where people feel comfortable during performing tasks with power assistive robots and there is a trade-off between the assisted torque or force to move the system and the performance to accomplish the task. We define the region of appropriate assistant level as the "cozy-zone". The results of this study can be a clue for finding the appropriate control of a power assistive system.