A Wearable Haptic Ring for the Control of Extra Robotic Fingers

This paper present a wearable haptic ring called "hRing" to control the soft extra robotic finger and to render haptic informations to provide cutaneous stimuli. The "hRing" is a novelwearable cutaneous device for the proximal finger phalanx and the extra robotic finger is a device to be used by chronic stroke patients to compensate for themissing hand function of their paretic limb. The hRing consists of two servo motors, a vibro motor, two pairs of push button and a belt. The servo motors move the belt placed in contact with the user's finger skin. When the motors spin in opposite directions, the belt presses into the user's finger, while when the motors spin in the same direction, the belt applies a shear force to the skin. The soft finger is an underactuated modular robotic finger worn on the paretic forearm by means of an elastic band. The device and the paretic hand/arm act like the two parts of a gripper working together to hold an object. It has been designed to be wearable, Two chronic stroke patients took part to our experimental evaluation on how the proposed integrated robotic system can be used for hand grasping compensation. The hRing enabled the patients to easily control the motion of the robotic finger while being provided the haptic feedback about the status of the grasping action. The patients found the system useful for ADL tasks, the hRing easy to use, and the haptic feedback very informative.