1. State Key Laboratory of Robotics, Shenyang Institute of Automation, Chinese Academy of Sciences, Shenyang 110016, China
2. Institutes for Robotics and Intelligent Manufacturing, Chinese Academy of Sciences, Shenyang 110016, China
3. University of Chinese Academy of Sciences, Beijing 100049, China
4. Institute of Urban Rail Transportation, Southwest Jiaotong University, Chengdu 610000, China
5. Shenyang Ligong University, Shenyang 110159, China
6. Shenyang Jianzhu University, Shenyang 110168, China
7. Department of Electrical and Electronic Engineering, The University of Hong Kong, Hong Kong 999077, Hong Kong