1. School of Information Engineering, Guangdong University of Technology, Guangzhou 510006, China
2. Key Laboratory of Biomimetic Robots and Systems, Ministry of Education, Beijing Institute of Technology, Beijing 100081, China
3. Institute of Mechanical Engineering, École Polytechnique Fédérale de Lausanne, Lausanne 1015, Switzerland
4. Department of Physical Education and Sports Engineering, Zhejiang University, Hangzhou 310028, China