Estimation of human operational feeling level for a lever manipulation task using shoulder angle and manipulability

Currently, the concept of ergonomically designed workplace using 3D graphic mannequins is gaining wide acceptance among the design engineers. However, predicting the human operational feeling level (i.e., comfort or discomfort level) during an ergonomic analysis of a virtual work situation is still in immature level. The current study is an attempt in that direction. This paper presents an approach that estimates the degree of comfort or discomfort felt by an operator during a lever manipulation task by using limb anthropometric and kinematic data. In this study, a haptic lever has been developed that emulates a lock-ball type lever action. Experiments were carried out with healthy male subjects under two different torque characteristics of the haptic lever. Using multiple regression analysis it has been found that the subjects operational feeling level can be estimated by means of shoulder flexion-extension angle and manipulability measure.