An articulation-type passive element is a planate bag containing articulating thin plates. It can be freely contracted and bent to fit an arbitrary rounded surface. Evacuation of the internal air renders the bag rigid so that it maintains whatever shape it has been given. The stiffness of the articulation-type passive element is proportional to the reduction in internal pressure below atmospheric pressure. Experimental results show that the stiffness is higher and more stable than that of other passive elements that function by vacuum pressure. As an application of the new passive element, we developed an orthopedic cast that is easy to remove or change in shape. The passive element is also applicable to wearable force displays. Passive elements fixed on an operator provide a sensation of reaction force by constraining his or her motion. The new passive element is suitable for wearable mechanisms, by virtue of being lightweight, soft, and safe.
The Japan Fluid Power System Society