1. Software School, North University of China, Taiyuan 030051, China
2. State Key Laboratory of Robotics, Shenyang Institute of Automation, Chinese Academy of Sciences, Shenyang 110169, People’s Republic of China
3. Institutes for Robotics and Intelligent Manufacturing, Chinese Academy of Sciences, Shenyang 110169, China
4. School of Mechanical Engineering, North China University of Water Resources and Electric Power, Zhengzhou 450045, China