Ergonomics of exoskeletons: Subjective performance metrics

In this paper it is shown how variation of the kinematic structure of an arm exoskeleton and variation of its fixation pressure on the human limb influences subjectively perceived task performance, such as comfort and the individual indices of the NASA TLX rating scale. It is shown by experimental results that the attachment pressure has a dominant effect on perceived comfort, mental load, physical demand and effort experienced by subjects and is optimal within a range of 10 30 mmHg. Furthermore, it is shown that the inclusion of passive compensatory joints inside an exoelectrons structure can reduce mental demand during a tracking task. When the outcome of this paper is interpreted in combination with a set of objective performance results that were presented earlier , the subjective performance metrics underline the fact that passive compensatory joints paired with an attachment pressure of 20 mmHg increase ergonomics and provide optimal conditions for task performance and comfort.