Analysis of Characteristics of Human Lifting Operation Leading to Discomfort Caused by the Difference Between Assumed Mass and Perceived Mass

In the human lifting operation, if the mass of the object is different from the assumed mass, human feels discomfort and cannot operate as desired. In this paper, the relationship between the lifting operation and the difference between the assumed mass and perceived mass is investigated. And it is clarified that what kind of operation leads to human discomfort caused by the difference between assumed mass and perceived mass.