1. School of Mechanical Engineering, Shandong University, Jinan, China
2. Key Laboratory of High Efficiency and Clean Mechanical Manufacture of MOE, Shandong University, Jinan, China
3. Engineering Research Center of Intelligent Unmanned System, Ministry of Education, Shandong University, Jinan, China
4. School of Rail Transportation, Shandong Jiaotong University, Jinan, China
5. School of Control Science and Engineering, Shandong University, Jinan, China