Design of an underactuated hand exoskeleton with joint estimation

In this study,we present an underactuated hand exoskeletonwith the adaptation for the shape and the size of the objects during grasping tasks. The realism of the grasping tasks are improved by allowing only the normal transmission of the forces on the finger phalanges. The absence of the tangential forces allows the device to be attached to the user’s finger in an easy and comfortable manner for the operation. Furthermore, the finger size adjustability can be ensured by the linkagebased design. Underactuation assures the automatic adjustability of the device for the grasping objects, while preventing the posture control of the finger phalanges. The undersensing disadvantage of the underactuation approach is suggested to be overcome by utilizing an additional potentiometer on the device in order to estimate the finger joints and the pose analysis of the mechanism during operation.