1. Institute of Systems Science and Technology Southwest Jiaotong University Chengdu China
2. Key Laboratory of Railway Industry of Advanced Energy Traction and Comprehensive Energy Conservation Southwest Jiaotong University Chengdu China
3. Department of Mechanical Engineering University of Kentucky Lexington Kentucky USA
4. School of Electrical Engineering Southwest Jiaotong University Chengdu China
5. College of Control Science and Engineering Zhejiang University Hangzhou China