1. Department of Mechano-Aerospace Engineering Tokyo Institute of Technology, 2-12-1 O-Okayama, Meguroku, Tokyo 152-8552, Japan
2. Department of Mechanical Environmental Engineering, Tokyo Institute of Technology, 2-12-1 O-Okayama, Meguroku, Tokyo 152-8552, Japan
3. Department of Precision Machining Engineering, Tokyo Denki University, 2-2 Kanda-Nishikicho, Chiyoda-ku, Tokyo 101, Japan