1. School of Electrical and Electronic Engineering, University of Leeds, Leeds, U.K.
2. School of Mechatronic Engineering and Automation, Shanghai University, Shanghai, China
3. Academic Department of Rehabilitation Medicine, University of Leeds, Leeds, U.K.
4. Institute of Rehabilitation Engineering, Binzhou Medical University, Yantai, China
5. School of Electronic and Electrical Engineering, University of Leeds, Leeds, U.K.