Study of 2D Vibration Summing for Improved Intensity Control in Vibrotactile Array Rendering

2D tactile arrays may be integrated into handheld devices or VR controllers to enhance user experience, for example, with touch communication for collaborative tasks. Multiple tactors (tactile elements) may be activated in combination to approximate a vibration point (virtual tactor) having arbitrary position and intensity. We studied the combination of intensities from multiple tactors to guide virtual tactor rendering approaches. Subjects matched perceived loudness of multi-tactor vibrations to a reference tactor. The multi-tactor vibrations corresponded to overall perceived positions halfway between tactor pairs and in the center of a 2D 4-tactor group. Results inform the relationship between tactor signal level and perceived loudness at these critical positions. The relationship leads us to propose a nonlinear 2D rendering approach, provides a basis for assessment of existing rendering techniques, and lays a foundation for further study of 2D array rendering.