Local Peak Method: An Electrotactile Stimulation Method Focusing on Surface Structures for Texture Rendering

Presenting objects’ texture sensations by electrical stimulation has been drawing greater attention as a means to improve the augmented reality experiences. To reproduce the texture sensations of real objects in detail, tactile perceptions of their complex surface shapes must be translated as electrical stimulation. Many conventional studies on presenting vibrational sensations by electrical stimulations have used single pulse waveforms, limiting the vibrational sensations that can be presented by electrical stimulations. In this paper, therefore, we propose the local peak method, in which pulse waveforms are configured on the objects’ surface structures. We have experimentally proved that the proposed local peak method can present sensations that are more akin to touching physical objects than pulse waveforms of single intervals in the case of presented objects having complex surface structures.

Combination of oriented-plane curvature reproduction and squeeze film effect-based texture reproduction to simulate curved and textured surface

The finger skin contains a variety of receptors, which provide multiple tactile sensing channels. When a finger touches the surface of an object, people can simultaneously perceive curvature, texture, softness, temperature, and so on. However, in most of research activities, the designed haptic feedback devices can only focus on a certain channel. In this paper, the rendering of curved and periodic textured surfaces involving two channels, i.e., curvature and texture, was studied. Two psychophysical experiments were conducted to investigate whether the coupling of kinesthetic feedback of curvature and tactile feedback of texture could reproduce curved and textured surfaces with high fidelity. The results showed a deviation of the point of subjective equality values in terms of curvature and roughness, indicating that the curvature rendering and texture rendering have an impact on each other. Therefore, it is necessary to correct the bias when making virtual rendering. The influence of curvature on texture rendering is reduced by recalculating and adjusting the spatial period of the synthesized texture in real-time; the influence of texture on curvature rendering is eliminate by compensating the force difference between touch on physical strip and artificial stimulus.