1. Faculty of Engineering; Gifu University; 1-1 Yanagido Gifu 501-1193 Japan
2. Department of Mechanical Engineering; Toyota National College of Technology; 2-1 Eisei-cho Toyota 471-8525 Japan
3. Department of Mechanical Engineering; Gifu University; 1-1 Yanagido Gifu 501-1193 Japan
4. Okuma Corporation; LTD, 5-25-1 Oguchi-cho 480-0193 Japan