Effect of Electrical Stimulation Haptic Feedback on Perceptions of Softness-Hardness and Stickiness While Touching a Virtual Object

With the advantages of small size and light weight, electrical stimulation devices have been investigated for providing haptic feedback in relation to virtual objects. Electrical stimulation devices can directly activate sensory receptors to produce a reaction force or touch sensations. In the current study, we tested a new method of electrically inducing force sensation in the fingertip, presenting haptic feedback designed to alter perceptions of softness, hardness and stickiness. We developed a 3D virtual reality system combined with finger-motion capture and electrical stimulation devices. We conducted two experiments to evaluate our electrical stimulation method and analyzed the effects of electrical stimulation on perception. The first experiment confirmed that participants could distinguish between the directions of the illusory force sensation, reporting whether the stimulation flexed their index finger forward or extended it backward. The second experiment examined the effects of the electric current itself on the intensity of their perception of the softness, hardness and stickiness of a virtual object.