1. Department of Assistive Technology, Research Institute, National Rehabilitation Center for Persons with Disabilities, Tokorozawa, Japan
2. Key Laboratory of Convergence Medical Engineering System and Healthcare Technology, the Ministry of Industry and Information Technology, Beijing Institute of Technology, Beijing, China
3. Graduate School of Engineering, Kagawa University, Takamatsu, Japan
4. Department of Intelligent Mechanical Systems Engineering, Kagawa University, Takamatsu, Japan
5. Department of Neurological Surgery, Faculty of Medicine, Kagawa University, Takamatsu, Japan