3 research outputs found
Online Exploration of an Unknown Region of Interest with a Team of Aerial Robots
In this paper, we study the problem of exploring an unknown Region Of
Interest (ROI) with a team of aerial robots. The size and shape of the ROI are
unknown to the robots. The objective is to find a tour for each robot such that
each point in the ROI must be visible from the field-of-view of some robot
along its tour. In conventional exploration using ground robots, the ROI
boundary is typically also as an obstacle and robots are naturally constrained
to the interior of this ROI. Instead, we study the case where aerial robots are
not restricted to flying inside the ROI (and can fly over the boundary of the
ROI).
We propose a recursive depth-first search-based algorithm that yields a
constant competitive ratio for the exploration problem. Our analysis also
extends to the case where the ROI is translating, \eg, in the case of marine
plumes. In the simpler version of the problem where the ROI is modeled as a 2D
grid, the competitive ratio is
where is the number of robots, and and are the robot speed and
the ROI speed, respectively. We also consider a more realistic scenario where
the ROI shape is not restricted to grid cells but an arbitrary shape. We show
our algorithm has
competitive ratio under some conditions. We empirically verify our algorithm
using simulations as well as a proof-of-concept experiment mapping a 2D ROI
using an aerial robot with a downwards-facing camera.Comment: 13 pages, 11 figures, Submitted to the International Journal of
Robotics Researc
Exploring Grid Polygons Online
We investigate the exploration problem of a short-sighted mobile robot moving
in an unknown cellular room. To explore a cell, the robot must enter it. Once
inside, the robot knows which of the 4 adjacent cells exist and which are
boundary edges. The robot starts from a specified cell adjacent to the room's
outer wall; it visits each cell, and returns to the start. Our interest is in a
short exploration tour; that is, in keeping the number of multiple cell visits
small. For abitrary environments containing no obstacles we provide a strategy
producing tours of length S <= C + 1/2 E - 3, and for environments containing
obstacles we provide a strategy, that is bound by S <= C + 1/2 E + 3H + WCW -
2, where C denotes the number of cells-the area-, E denotes the number of
boundary edges-the perimeter-, and H is the number of obstacles, and WCW is a
measure for the sinuosity of the given environment.Comment: 49 pages, 45 figure
Exploring an Unknown Cellular Environment
We investigate the exploration problem of a short-sighted mobile robot moving about in an unknown cellular room. In order to explore a cell, the robot must enter it. Once inside, the robot knows which of the 4 adjacent cells exist and which are boundary edges. The robot starts from a specified cell adjacent to the room's outer wall; it visits each cell, and returns to the start. Our interest is in a short exploration tour, that is, in keeping the number of multiple cell visits small. For abitrary environments containing obstacles we provide a strategy producing tours of length S # C+ 1 2 E+H- 3, where C denotes the number of cells---the area---, E denotes the number of boundary edges---the perimeter---, and H is the number of obstacles