Filtered Medial Surface Based Approach for 3D Collision-Free Path Planning Problem

This paper introduces an original 3D path planning approach for Unmanned Aerial Vehicle (UAV) applications. More specifically, the core idea is to generate a smooth and collision-free path with respect to the vehicle dimension. Given a 3D grid representation of the environment, the Generalized Voronoi Graph (GVG) is first approximated using a filtered medial surface (FMS) algorithm on the corresponding navigable space. Based on an efficient pruning criterion, the produced FMS excludes GVG portions corresponding to narrow passages unfitting safe UAV navigation constraints, and thus it defines a set of guaranteed safe trajectories within the environment. Given a set of starting and destination coordinates, an adapted A-star algorithm is then applied to compute the shortest path on the FMS. Finally, an optimization process ensures the smoothness of the final path by fitting a set of 3D Bézier curves to the initial path. For a comparative study, the A-star algorithm is applied directly on the input environment representation and relevant comparative criteria are defined to assert the proposed approach using simulation results.

Sensor-based exploration for planar two-identical-link robots

We present a new roadmap based on a generalized Voronoi graph for two-identical-link mobile robots to explore an unknown planar environment. It is called the L2-generalized Voronoi graph and is defined in terms of workspace distance measurements using only sensor-provided information, with the robot having the maximum distance from obstacles, and is therefore optimum in a point of view for exploration and obstacle avoidance. The configuration of the robot possesses four degrees of freedom, and hence the roadmap is one-dimensional in an unknown configuration space [Formula: see text]. The L2-generalized Voronoi graph is not always connected, and so is connected with an additional structure called the L2R-edge, where the robot is tangent to a GVD structure with the same orientation for the two links. This roadmap is termed L2 hierarchical generalized Voronoi graph. The L2 hierarchical generalized Voronoi graph includes two structures: the L2 hierarchical generalized Voronoi graph and the L2R edge. Although the condition of two identical links looks somewhat constraining, the L2 hierarchical generalized Voronoi graph is still worth pursuing because the case is very common in the engineering environment.