1. Department of Biomedical Engineering, Xi’an Technological University, Xi’an 710021, China
2. School of Electronic Information Engineering, Xi’an Technological University, Xi’an 710021, China
3. Rehabilitation Engineering Lab, Department of Kinesiology and Community Health, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
4. Carle Foundation Hospital, Urbana, IL 61801, USA