[4] SHANG E K,AN X J,WU T,et al.LiDAR based negative obstacle detection for field autonomous land vehicles［J］.Journal of Field Robotics,2015,33(5):591-617.

[5] SHANG E K,AN X J,LI J,et al.A novel setup method of 3D LiDAR for negative obstacle detection in field environment［C］//IEEE 17th International Conference on Intelligent Transportation Systems,2014:1436-1441.

[7] SERBAN R,WANG S K,LO M W,et al.Halo orbit mission correction maneuvers using optimal control［J］.Automatica,2002,38(4):571-583.