1. Key Laboratory of Electronic Equipment Structure Design, Ministry of Education, Xidian University, Xi'an, Shannxi, China
2. Department of Mechanical Engineering, University of California, Berkeley, CA, USA
3. Nanjing Research Institute of Electronics Technology, Nanjing, Jiangsu, China
4. State Key Laboratory of Advanced Design and Manufacturing for Vehicle Body, Hunan University, Changsha, Hunan, China