1. Department of Mechanical Design Engineering, School of Mechanical Engineering, Hefei University of Technology, Hefei 230009, China;
2. Mechanical Engineering Department, Missouri University of Science and Technology, Rolla, MO 65401
3. Department of Mechanical Design Engineering, School of Mechanical Engineering, Hefei University of Technology, Hefei 230009, China
4. The Institute of Robotics, School of Mechanical Engineering, Shanghai Jiao Tong University, Shanghai 200240, China