1. Graduate School of Engineering, Department of Robotics, Tohoku University, 6-6-01 Aoba, Aramaki, Aoba-ku, Sendai, Miyagi, Japan
2. Graduate School of Engineering, Department of Finemechanics, Tohoku University, 6-6-01 Aoba, Aramaki, Aoba-ku, Sendai, Miyagi, Japan