Comfort estimation during lift-up using nursing-care robot — RIBA

In our research center, we have developed a nursing-care assistant robot - RIBA, which can lift up and transfer person between bed and wheelchair using its two human like arms. In this research, we develop a new method to estimate the comfortable feeling of human, which can help our robot - RIBA to find the best lifting-up motion automatically. By using a lifting-up model and optimizing a weighted evaluation function, we can calculate the lifting forces and the human joint torques during the lift-up. A weighted evaluation is used to reflect the change of comfortable feeling. We also carried out some experiments to check the model and the estimating method. During the lift-up, we measured subjects´ EMG signal. And after the lift-up, questionnaires survey is conducted. The change trends between estimated and measured value show the effectiveness of the model and the method quantitatively and qualitatively.