Smooth Trajectory Generation for Gap Traversal by UAVs

A path planning method for traversing through gaps is proposed for Unmanned Aerial Vehicles (UAVs) to address their wide applications in cluttered environments. The existing method in the literature solves this problem by generating a C0-type path and does not consider the initial orientation of the vehicle. This limits its real-time applicability, as the vehicle is required to stop at several points and reorient. In the proposed method, the initial orientation of the UAV is considered while developing the trajectory, ensuring that the vehicle can start smoothly and move continuously through multiple gaps without stopping. The initial reference path of C1-type is generated using the Dubins path to optimize the path length, and then, using the carrot-chasing algorithm, the path is made smoother with C2-type continuity, as well as near-optimal. Furthermore, the developed path satisfies the prescribed curvature bound, ensuring that the lateral acceleration requirement is consistently met. The algorithm is simple, easy to implement, and requires only bearing-based measurements to detect the wall edges. Finally, a comparative study is conducted to demonstrate the efficacy of the proposed method compared to an existing bearing-based gap traversal method.