In order to attach the exoskeleton to the user's body, we developed a simple cuff and strap system. The cuffs are cut from a PVC pipe with half of it removed to allow the placement of the user's arm. Orange velcro straps, seen in Figure 1, were placed through slots in the cuff to allow the tightening and closing of the cuff on the user's arm. The bicep cuff was placed near the center of the lower arm linkage while the forearm cuff was placed near the center of the inner forearm linkage to allow the user's arm to move comfortably with the exoskeleton. In this version, an extended bolt on the hand linkage was used to allow the user to hold and move the exoskeleton. Thin foam padding was placed on the interior of the cuffs to provide a cushioning support and prevent chaffing of the user's arm.
Figure 1. Cuff and Fixed Hip interface on initial prototype.
In order to provide a ground for the mechanism, a wooden shaft with an extended block was placed on the shoulder end of the exoskeleton. Straps were then threaded through the block to wrap around the user's body and ground the mechanism. Unfortunately, we found that this method did not work well because there was movement on the upper section of the shoulder. See Interface With Body (Final Implementation) for improvements.