Development of a wearable haptic device that presents haptics sensation of the finger pad to the forearm

While many wearable tactile displays for the fingers, such as fingertip-type and glove-type displays, have been developed, their weight and size typically hinder the free movement of fingers, especially when considering the multi-finger scenario. We propose a method of presenting the haptics sensation of the fingertip on the forearm, not on the fingertip, to address this issue. A five-bar linkage mechanism was adopted to present a two-degree-of-freedom force. We conducted two experiments. In the first experiment, we presented a pressure sensation and a horizontal friction sensation perceived by the index finger to multiple sites of the forearm to search for a proper location of presentation, finding that the volar part of the wrist is optimal. On the basis of this result, we developed a device for the index finger and thumb, and conducted a second experiment to present the grasping force in a virtual reality environment. The realism of the experience in virtual reality was better when using the designed device than for no haptics cue or for vibration conditions.