Efficient Terrain-Following Path Planning and Trajectory Tracking Control for Fixed-Wing UAV

Terrain-following technology is critical for fixed-wing UAVs' low-altitude penetration. This study proposes a novel path planning algorithm and tracking control system to address flight control challenges in complex terrains. Existing terrain-following algorithms often fail to balance real-time performance and path optimality while satisfying kinodynamic constraints. The research introduces targeted improvements to the traditional Informed RRT* algorithm, achieving efficient path search in complex terrain through elliptical sampling optimization and kinodynamic constraint modeling. Notably, the algorithm deeply integrates terrain elevation data with a 6-DOF dynamic model, precisely controlling pitch and yaw rates to ensure flight paths closely follow terrain contours while fully complying with aircraft maneuvering limits. A backstepping-based nonlinear tracking controller further guarantees system stability and robustness during terrain-following. Experimental results demonstrate the solution's effectiveness in achieving kinodynamic-constrained terrain-following, significantly improving planning efficiency and tracking accuracy while ensuring flight safety, providing reliable technical support for fixed-wing UAV low-altitude penetration missions.