  In this paper, a method of rendering aerial haptics that uses an aerodynamic
vortex and focused ultrasound is presented. Significant research has been
conducted on haptic applications based on multiple phenomena such as magnetic
and electric fields, focused ultrasound, and laser plasma. By combining
multiple physical quantities; the resolution, distance, and magnitude of force
are enhanced. To combine multiple tactile technologies, basic experiments on
resolution and discrimination threshold are required. Separate user studies
were conducted using aerodynamic and ultrasonic haptics. Moreover, the
perception of their superposition, in addition to their resolution, was tested.
Although these fields cause no direct interference, the system enables the
simultaneous perception of the tactile feedback of both stimuli. The results of
this study are expected to contribute to expanding the expression of aerial
haptic displays based on several principles.
