1. School of Mechanical Engineering and Automation, Beihang University, Beijing, China
2. School of Mechanical and Electrical Engineering, Guangxi Key Laboratory of Manufacturing System & Advanced Manufacturing Technology, Guilin University of Electronic Technology, Guilin, China
3. Department of Mechanical Engineering, Tsinghua University, Beijing, China
4. Faculty of Materials and Manufacturing, Beijing University of Technology, Beijing, China
5. State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources, North China Electric Power University, Beijing, China