1. State Key Laboratory of Robotics and System, Harbin Institute of Technology, West Da-zhi Street 92, Harbin, Heilongjiang 150001, People's Republic of China
2. School of Engineering and Applied Sciences and Department of Physics Harvard University, 9 Oxford Street, Cambridge, MA 02138, USA
3. Chang’an University, Middle-Section of Nan’er Huan Road, Xi’an 710000, China
4. School of Mechatronics Engineering, Harbin Institute of Technology, West Da-zhi Street 92, Harbin 150001, People's Republic of China