1. School of Electronics and Control Engineering, Chang’an University, Xi’an, Shaanxi 710064, China
2. School of Mechatronics Engineering, Harbin Institute of Technology, West Da-zhi Street 92, Harbin, Heilongjiang 150001, People’s Republic of China
3. State Key Laboratory of Robotics and System, Harbin Institute of Technology, West Da-zhi Street 92, Harbin, Heilongjiang 150001, People’s Republic of China