1. Key Laboratory of Intelligent Rehabilitation and Neromodulation of Hebei Province, Yanshan University at Qinhuangdao, Qinhuangdao 066004, China
2. School of Control Engineering, Northeastern University at Qinhuangdao, Qinhuangdao 066004, China
3. School of Biological Science and Medical Engineering, Beihang University, Beijing 100191, China
4. Beijing Advanced Innovation Centre for Biomedical Engineering, Beihang University, Beijing 100191, China
5. Department of Mechanical and Biomedical Engineering, City University of Hong Kong, Kowloon, Hong Kong 999077, China