1. Department of Biomedical Engineering, The Hong Kong Polytechnic University, Hong Kong SAR 999077, China
2. Research Institute for Smart Ageing, The Hong Kong Polytechnic University, Hong Kong SAR 999077, China
3. School of Mechanical Engineering, Tongji University, Shanghai 200082, China
4. Institute of Rehabilitation Engineering and Technology, University of Shanghai for Science and Technology, Shanghai 200093, China