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Tele-ping pong: proof-of-principle of an IT-engineered wormhole


Robotic-based tele-existence has been studied in our lab in collaboration with Mabuchi Lab and Shimojo Lab [1]. This was an advanced form of tele-presence allowing the user to feel and interact with object at a distance. With this project we try to bring the experience to the next level by simulating the teleportation of a physical object through internet, thus creating an artificial (IT-engineered!) gravitational wormwhole. One can argue that, if all the structural information of a physical object could be transmitted through internet, and then on the other side a machine could exactly reconstructs the object based on this information (very much like "total fax" machine), this would be, if not exactly the same, something very close to SF-teleportation. We then set ourselves to simulate the teleportation of a ping-pong ball in a ping-pong game where the users are very far away from each other. Thanks to vision-chip based high-speed tracking [2], we can acquire in real time all the parameters of the relevant phase space of the ball (namely, its position, speed and spin [4]). Then, using high-speed and high-precision robotic arms such as the one used in our catching/throwing experiments [5], one can in principle catch the ball on one side, and throw another ball on the other side - with copied, identical dynamical parameters.

A prototype system was developed and successfully demonstrated in two dimensions, taking advantage of the research already done in our lab on a vision chip-based air-hockey system [3]. This configuration (namely a tele-air hockey system) was discussed in 2005 with a researcher in Australia who then went on developing a very similar system but without real transmission of the puck momentum, nevertheless demonstrating the thrilling possibilities of social interaction generated by physical games at a distance. We are now designing an electromagnetic catcher/ launcher mounted on a high-speed linear motor (THK GLM10) to exactly reproduce the momentum of the puck [6]. The delay for transmission is incompressible (not a real gravitational wormhole!), but the robot launching-time (i.e. setting the linear motor to the right speed/position) can be compensated by predicting the projectile trajectory and sending this data before the actual ball is caught in front of the screen.

Movies (preliminary experiments)


  1. M. Shimojo, T. Suzuki, A. NAMIKI, T. Saito, M. Kunimoto, R. Makino, H. Ogawa, M. Ishikawa and K. Mabuchi : Development of a System for Experiencing Tactile Sensation from a Robot Hand by Electrically Stimulating Sensory Nerve Fiber, 2003 IEEE International Conference on Robotics and Automation (Taipei, Taiwan, 2003.9.16) pp.1264-1270.
  2. T. Komuro, I. Ishii, M. Ishikawa and A. Yoshida: A Digital Vision Chip Specialized for High-speed Target Tracking, IEEE transactions on Electron Devices, Vol.50, No.1, pp.191-199 (2003) [PDF]
  3. Vision Chip based Air Hockey Game (developed with SEIKO Precision, Inc.)
  4. Y. Watanabe, T. Komuro, S. Kagami, M.Ishikawa: Real-time Visual Measurements using High-speed Vision, Optics East (Philadelphia 2004.10.28) / Machine Vision and its Optomechatronic Applications, Proceedings of SPIE Vol. 5603, pp. 234-242. [PDF].
  5. A. Namiki, Y. Imai, T. Senoo and M. Ishikawa. Dynamic Manipulation Using High-speed Multifingered Hand-Arm System -Grasping, Catching, and Batting-. 2004 IEEE International Conference on Robotics and Automation. (New Orleans, USA, 2004. 4.26-5.1) / Video Proceedings, No.L.
  6. N. Danbara Master thesis, University of Tokyo (Feb. 2005). In Japanese only [PDF-8MB].
Ishikawa Group Laboratory, Data Science Research Division, Information Technology Center, University of Tokyo / Tokyo University of Science
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