1. Key Laboratory of Fluid and Power Machinery, Ministry of Education, Key Laboratory of Automobile Measurement and Control & Safety, Xihua University, Chengdu 610039, China
2. College of Mathematics and Statistics, Hanshan Normal University, Chaozhou 521041, China
3. Key Laboratory of Automobile Measurement and Control & Safety, Xihua University, Chengdu 610039, China
4. State Key Laboratory of Traction Power, Southwest Jiaotong University, Chengdu 610031, China