1. Department of Mechanical and Automation Engineering; The Chinese University of Hong Kong; Shatin N.T., Hong Kong China
2. Institute of Robotics and Intelligence Systems (IRIS); ETH Zurich; CH-8092 Zurich Switzerland
3. Robotics Engineering Department; Daegu Gyeongbuk Institute of Science and Technology (DGIST); 711-873 Daegu South Korea
4. Shenzhen Research Institute; The Chinese University of Hong Kong; 518100 Shenzhen China