1. Advanced Institute of Industrial Technology,Tokyo,Japan,140-0011
2. Waseda University,Department of Integrative Bioscience and Biomedical Engineering,Tokyo,Japan
3. Sony Corporation,Tokyo,Japan
4. Waseda University,Department of Modern Mechanical Engineering,Tokyo,Japan
5. Global Center for Science and Engineering and the Humanoid Robotics Institute (HRI), Waseda University,Tokyo,Japan