1. School of Electronics and Control Engineering Chang'an University Middle‐Section of Nan’er Huan Road Xi'an 710064 P. R. China
2. School of Mechatronics Engineering Harbin Institute of Technology West Da‐zhi Street 92 Harbin 150001 P. R. China
3. College of Art Heilongjiang University No. 74 Xuefu Road Harbin 150001 P. R. China
4. State Key Laboratory of Robotics and System Harbin Institute of Technology West Da‐Zhi Street 92 Harbin Heilongjiang 150001 P. R. China