1. School of Mechanical Engineering, Southwest Jiaotong University, Chengdu 610031, P. R. China
2. Yibin Research Institute, Southwest Jiaotong University, Yibin 64000, P. R. China
3. Graduate School of Advanced Science and Engineering, Hiroshima University, Higashi, Hiroshima 7390046, Japan
4. School of Information Science and Technology, Southwest Jiaotong University, Chengdu 610031, P. R. China
5. Chengdu Technological University, Chengdu 611730, P. R. China