Fig. 1
From: Quantification of upper limb position sense using an exoskeleton and a virtual reality display
KINARM Exoskeleton Lab. a Modified wheelchair with each arm supported against gravity by exoskeletons; (b) Virtual reality display; (c) Virtual arm and real arm positions (blue line; non-visible for the participant) where ∆Θ represents the angular difference between the real and the virtual arm. The white circle corresponds to the center of rotation, i.e. the elbow joint