An enhanced search algorithm of a landing site on unknown terrain using stereo vision information for a quadrotor unmanned aerial vehicle is developed. For the development, a quadrotor dynamic model, including nonlinear actuator dynamics, is constructed and guidance and control system is designed based on feedback linearization and linear quadratic tracker. Stereo vision sensor is used to acquire depth map information of the terrain and flatness information of the topography is obtained by extracting the edge of the depth map and performing Euclidean distance transform. Energy consumption of the quadrotor is also considered. The three measures of: 1) the depth; 2) the flatness; and 3) the energy consumption are combined to propose a performance index to determine the safe landing spot of the quadrotor. Numerical simulation is performed to verify the performance of the proposed algorithm and hardware system applicable to practical implementation is also included.
- Autonomous landing
- depth map
- quadrotor system
- stereo vision
- unmanned aerial vehicle (UAV)