[1] Graduate School of Advanced Science and Engineering, Waseda University, Japan
[2] Faculty of Science and Engineering, Waseda University, Japan
[3] Humanoid Robotics Institute (HRI), Waseda University, Japan
[4] ALOKA Co. Ltd., Japan
[5] Department of Medical Engineering, Himeji Dokkyo University, Japan
[6] Biomedical Engineering Department, Musashi Institute of Technology, Japan