A social haptic device to create continuous lateral motion using sequential normal indentation

Touch is an essential method for communicating emotions between individuals. Humans use a variety of different gestures to convey these emotions, including squeezes, pats, and strokes. This paper presents a device for creating a continuous lateral motion on the arm to mimic a subset of the gestures used in social touch. The device is composed of a linear array of voice coil actuators that is embedded in a fabric sleeve. The voice coils are controlled to sequentially press into the user's arm to create the sensation of linear travel up the arm. We evaluate the device in a human-subject study to confirm that a linear lateral motion can be created using only normal force, and to determine the optimal actuation parameters for creating a continuous and pleasant sensation. The results of the study indicated that the voice coils should be controlled with a long duration for each indentation and a short delay between the onset of indentation between adjacent actuators to maximize both continuity and pleasantness.