1. Department of Mechanical Engineering and Automation, Beihang University, Beijing, China.
2. Department of Robotics and Intelligent Systems, Wuhan University of Science and Technology, Wuhan, China.
3. Sino-French Engineer School, Beihang University, Beijing, China.
4. Department of Aeronautic Science and Engineering, Beihang University, Beijing, China.
5. Department of Artificial Intelligence, Beijing University of Posts and Telecommunications, Beijing, China.
6. Department of Computer Science, Tsinghua University, Beijing, China.