Proposal of Function Approximation Model for Prediction of Total Perceived Discomfort on Upper Limb

The aim of this study was to formulate the relationship between the total perceived discomfort of the upper limb and perceived discomforts of each degree of freedom (DOF). The biomechanical analysis was performed based on the posture and load classification of the rapid upper limb assessment (RULA), and the joint moments and perceived discomforts of each DOF were calculated. The summary score of the RULA and the perceived discomforts of each DOF were taken as the objective and explanatory variables respectively. Three approximation models (i.e., the average, maximum, and hybrid of average and maximum) were compared in terms of the accuracy of predicting the total perceived discomfort. The result indicated that the dominant factor of total discomfort may transit from the average discomforts to the maximum discomfort. In addition, the hybrid model had the highest accuracy among the three models.