1. Department of Engineering, Kwansei Gakuin University, 1 Gakuen-Uegahara, Sanda 669-1330, Japan
2. Department of Mechanical Systems Engineering, The University of Shiga Prefecture, 2500 Hassaka-cho, Hikone 522-0057, Japan
3. Department of Mechanical Science and Engineering, Hirosaki University, 3 Bunkyou-cho, Hirosaki 036-8561, Japan
4. Department of Intelligent Mechatronics, Akita Prefectural University, 84-4 Aza-Ebinokuchi, Yurihonjo 015-0055, Japan