Yuichi Tsumaki, Takeshi Ohgi, Arata Niiyama, Development of a Spherical Haptic Interface with Infinite Workspace, Proceedings of the International Symposium on Robotics and Intelligent Sensors, Nagoya, Japan, pp. 39-44, 2010.
Yuichi Tsumaki, Takeshi Ohgi and Arata Niiyama, A Spherical Haptic Interface with Unlimited Workspace, International Journal on Smart Sensing and Intelligent Systems, Vol. 3, No. 3, pp. 376-388, 2010.