The Effect of Support Level and Arm Angle on Passive Arm Support Exoskeleton Perceived Weight Reduction

Abstract

This study tested 10 engineering students at Liberty University to determine the effect of various shoulder angles and support level settings on the perceived weight reduction of upper extremity exoskeletons (EXOs). It also examined the impact of support levels and the choice of two different EXOs. Effectiveness was determined by finding the minimum discrete value of a variable weight in a participant’s EXO supported arm at which the participant would assert that they could hold a control weight in their other, unsupported arm for an equal or longer duration. Results indicated that shoulder angle and support level setting were significant factors in determining the perceived weight of equivalence. Arm tested and choice of EXO did not prove significant. Findings indicate that arm support EXOs are more effective when the user’s upper arm is perpendicular to their body and when oriented 120º upward from resting position, and that higher support levels provide the highest reduction in perceived weight.