Navigability analysis of natural terrains with fuzzy elevation maps from ground-based 3D range scans

Abstract

-Mobile robot navigation through natural terrains is a challenging issue with applications such as planetary exploration or search and rescue. This paper proposes navigability assessment of natural terrains scanned from groundbased 3D laser rangefinders. A continuous model of the terrain is obtained as a fuzzy elevation map (FEM). Based on this model, the proposed solution incorporates terrain navigability both in terms of uncertainties of the 3D input data and slope of the fuzzy surface. Moreover, the paper discusses the application of this method for local path planning. For this purpose, the Bug algorithm has been adapted to compute local paths on the navigable region of the FEM. The method has been applied to actual 3D point clouds on two different experimental sites. Abstract-Mobile robot navigation through natural terrains is a challenging issue with applications such as planetary exploration or search and rescue. This paper proposes navigability assessment of natural terrains scanned from ground-based 3D laser rangefinders. A continuous model of the terrain is obtained as a fuzzy elevation map (FEM). Based on this model, the proposed solution incorporates terrain navigability both in terms of uncertainties of the 3D input data and slope of the fuzzy surface. Moreover, the paper discusses the application of this method for local path planning. For this purpose, the Bug algorithm has been adapted to compute local paths on the navigable region of the FEM. The method has been applied to actual 3D point clouds on two different experimental sites.

Field Navigation Using Fuzzy Elevation Maps Built with Local 3D Laser Scans

“…Instead of using the adaptive neuro-fuzzy inference system (ANFIS) for identification [16,18,19], least squares fuzzy modeling [29] has been employed to improve computation time. Additionally, cylindrical coordinates (α, r, z) have been employed instead of Cartesian coordinates (x, y, z).…”

“…Whenever the checked point has a reliability value on the FRM less than 0.75, or has a gradient magnitude on the FEM greater than 0.35, or reach the borders of the FEM, the distance D i , which is initially zero, is not increased more. The gradient of the FEM ∇H is employed to detect non traversable areas [18]. The magnitude of the gradient at a point with cylindrical coordinates (α, r) on the FEM can be calculated as:…”

“…Moreover, fuzzy elevation maps (FEMs) can operate with measurement uncertainty of the sensors [16,17]. However, fuzzy interpolation can produce unreliable solutions in areas with sparse measurements, and it is necessary to use a fuzzy reliability mask (FRM) for each FEM [18,19].…”

Collapsible cubes: Removing overhangs from 3D point clouds to build local navigable elevation maps

“…Furthermore, the resulting point clouds has been applied to build standard and fuzzy elevation maps (FEMs) of these outdoor scenes. Future work includes autonomous navigation tests with the Quadriga mobile robot based on local planned paths from the FEMs [24]. …”

Building Fuzzy Elevation Maps from a Ground-Based 3D Laser Scan for Outdoor Mobile Robots

“…Moreover, ANFIS was preliminarily proposed to obtain fuzzy elevation maps of natural terrain from ground-based 3D data [23]. These elevation maps have been already employed for assessing traversability and local path planning [24].…”