Wearable Haptic Device Presenting Sensations of Fingertips to the Forearm.

Several existing haptic displays used in virtual reality (VR) environments present haptic sensations generated by the fingertips in the VR to actual fingertips. However, these devices face certain challenges, such as physical interference between the devices, particularly when multi-degree-of-freedom (DOF) force needs to be presented to multiple fingers. To address this issue, we propose a haptic presentation method that transmits haptic sensations generated by the fingertips in the VR, including the direction of the force, to the forearm. We previously　proposed a method to present both magnitude and direction of the force applied to the index finger using a five-bar linkage mechanism, which transmits the force sensation with two DOF to the forearm. In this study, the forces in the downward and left-right directions were obtained from the kinematics of a five-bar linkage mechanism for accurate force presentation. Additionally, we conducted a user study evaluating user grasping an object in the VR and performing task. The results verified the haptic sensation of the force transmitted by the proposed prototype to the user's forearm provides a sufficient comfort level. Furthermore, the task execution time and comfort level were comparable to those of a vibrotactile presentation presented directly to the fingertips.