1. School of Computer Science and Engineering, Changchun University of Technology, Changchun 130012, China
2. National Engineering Laboratory, CRRC Changchun Railway Vehicles Co., Ltd., Changchun 130062, China
3. Department of Automation, Tsinghua University, Beijing 100084, China
4. School of Mechatronic Engineering, Changchun University of Technology, Changchun 130012, China