1. College of Mechanical Engineering, Tianjin University of Science & Technology, No. 1038, Dagu Nanlu, Hexi District, Tianjin, P. R. China
2. Tianjin Key Lab of Integrated Design and On-line Monitoring for Light, Industry & Food Machinery and Equipment, Tianjin, P. R. China
3. National Research Centre for Rehabilitation Technical Aids, No. 1, Ronghuazhonglu, BDA, Beijing, P. R. China
4. Beijing Key Laboratory of Rehabilitation Technical Aids for Old-Age Disability, No. 1, Ronghuazhonglu, BDA, Beijing, P. R. China
5. Department of Traumatic Orthopaedics, Tianjin Hospital, No. 406, Jiefang Nanlu, Hexi District, Tianjin, P. R. China
6. Key Laboratory for Biomechanics and Mechanobiology of Ministry of Education, School of Biological Sciences and Medical Engineering Beihang University, Beijing 100191, P. R. China