Online motion planning for autonomous vehicles in vast environments

Nowadays, the potential of autonomous vehicles for order picking and material transport in vast environments with large amounts of obstacles is only exploited to a limited extent. In order to realize free, time-optimal motion of autonomous vehicles through such complex environments, this paper presents a novel motion planning approach. The approach combines a global path planner with a local trajectory generator. The global planner finds a path through the complete environment, taking only the stationary obstacles into account. The local trajectory generator computes a detailed trajectory in a local frame around the global path, accounting for both stationary and moving obstacles. This trajectory is parameterized as a spline, and is obtained by solving an optimal control problem. In order to always include the latest information about the environment, the optimal control problem is solved online with a receding horizon. The paper demonstrates the potential of the proposed method with extensive numerical simulations. In addition, it presents an experimental validation in which a KUKA youBot moves through an obstructed environment. To facilitate the numerical and experimental validation of the presented method, it is embodied in a user-friendly open-source software toolbox.