Hopping-Pong Redirects Ping Pong Balls Using Ultrasound Phased Arrays
University of Tokyo’s system was designed using a nine-panel phased array outfitted with ultrasonic transducers and a depth camera.
Scientists at the University of Tokyo’s Shinoda & Makino Lab have designed an ultrasound phased array capable of changing the trajectory of a ping pong ball (PPB) in flight. While that doesn’t sound too interesting, the device has potential in many applications, including removing defective samples in food production, used in augmented sports, and changing the direction of an object thrown by humans, among a host of others.
Hopping-Pong is a non-contact ultrasound platform capable of controlling objects using a computationally controlled force, which is accomplished using high-speed measurement, prediction of the trajectory, and the presentation of said ultrasound force. The platform was designed using nine AUPAs (Airborne Ultrasound Phased Array) units outfitted with 248 individually driven ultrasound transducers, a pair of Ximea MQ003CG-CM high-speed cameras, and a Windows-based PC to control them.
Hopping-Pong employs a right-handed XYZ coordinate system that begins in the lower left-hand corner of the ultrasound array, which is used to measure the three-dimensional position of the ping pong ball in flight utilizing the cameras. More accurately, the platform detects the pixel positions of the 3D PPB by triangulation, which is then converted to 2D using calibrated parameters.
More information on Hopping-Pong can be found in a recently published paper, entitled “Hopping-Pong: Changing Trajectory of Moving Object Using Computational Ultrasound Force."