Midair Haptics, Airborne Ultrasound Tactile Display


The Airborne Ultrasound tactile Display (AUTD) is a device that remotely creates vibrotactile sensation on a human skin surface by generating focused airborne ultrasound. The device does not require users to wear any bulky instruments. An array of ultrasound transducers are mounted on the surface of the AUTD, which creates a focus of airborne ultrasound at an arbitrary position in the air. At the focal point, static pressure called “acoustic radiation pressure” is produced due to the intense ultrasound pressure amplitude. The focal position and intensity can be switched quickly (at 2,000 Hz). Modulated radiation pressure on a skin produces various tactile sensations.

Based on the phase array technique, the focal position can be electrically adjusted. In the technique proper phase shift is added to each transducer to compensate the phase delay due to the distance between each transducer and the desired focal position. The physical interpretation of the technique is well understood as an acoustic lens to gather ultrasound energy at a spot. The focusing performance (i.e. proper focusing in far field without being blurred) highly depends on the aperture of the lens, namely, the size of the ultrasound array. We have developed the framework to operate multiple transducer array units in harmony so as to achieve a large synthetic aperture.

fireworks_handAUTD can generate tactile stimuli with various vibrational textures by switching the focal intensity temporally. The temporal profile of the vibration can be designed in the range of sufficiently high frequencies (~1,000Hz) for human tactile perception. We can design a variety of the vibrotactile experience such as exploding fireworks, creeping inchworms, small rubber ball hit on the palm and so on. Our demo system of Tactile Projector projects visual images and ultrasound vibrotactile stimuli at the same position on our body surface simultaneously. We can see and feel the existence of virtual objects touching our bodies.

◆For more information:

Airborne Ultrasound Tactile Display (AUTD)  (youtube video SIGGRAPH 2008 E-tech)

The first study of midair haptic feedback using ultrasound

Touchable Holography (youtube video SIGGRAPH 2009 E-tech)

The first demo of midair haptic feedback synchronized with visual floating images

Tactile Projector  (youtube video IEEE WHC 2013)

Haptomime, Mid-Air Haptic Touch Panel  (youtube)

3D Haptic hologram (youtube 1,  youtube 2)

Haptoclone (Haptic & optical clone) (youtube)

Symmetric mutual telexistence by 3D haptic & optical field reconstruction

Related researches by related laboratories:
Three-Dimensional Mid-Air Ultrasonic Manipulation by
Mr. Yoichi Ochiai in Prof. Jun Rekimoto laboratory (Univ. of Tokyo) and Assistant Professor Takayuki Hoshi (Nagoya Institute of Technology), alumnus of Shinoda lab, Univ. of Tokyo.