Hazard detection and avoidance for planetary landing based on Lyapunov control method

Future planetary landers must be capable of detecting hazards in the landing zone and maneuvering to a new and safe site, for the requirements of the scientific task. This paper presents an autonomous hazard detection and avoidance method based on Lyapunov control method for planetary landing. The terrain of the landing zone is first reconstructed using the feature points of pictures at two different time, and the plane of the landing zone was determined by fitting the terrain elevation data. Then, hazards in the landing zone were identified according to the vitual plane. In order to reduce the potential threats by the hazards, an avoidance control law is designed using Lyapunov function method. The control law can guarantee the landers reach the safe site, simultaneously decrease the landing speed to zero. The results of numerical simulation show that the method is satisfactory for hazards detection and avoidance with assumed environments.