eng
Schloss Dagstuhl – Leibniz-Zentrum für Informatik
Dagstuhl Seminar Proceedings
1862-4405
2007-02-07
6421
1
12
10.4230/DagSemProc.06421.1
article
06421 Abstracts Collection – Robot Navigation
Fekete, Sándor
Fleischer, Rudolf
Klein, Rolf
Lopez-Ortiz, Alejandro
From 15.10.06 to 20.10.06, the Dagstuhl Seminar 06421 ``Robot Navigation''generate automatically was held in the International Conference and Research Center (IBFI),
Schloss Dagstuhl.
During the seminar, several participants presented their current
research, and ongoing work and open problems were discussed. Abstracts of
the presentations given during the seminar as well as abstracts of
seminar results and ideas are put together in this paper. The first section
describes the seminar topics and goals in general.
Links to extended abstracts or full papers are provided, if available.
https://drops.dagstuhl.de/storage/16dagstuhl-seminar-proceedings/dsp-vol06421/DagSemProc.06421.1/DagSemProc.06421.1.pdf
Motion planning
robotics
computational geometry
online algorithms
eng
Schloss Dagstuhl – Leibniz-Zentrum für Informatik
Dagstuhl Seminar Proceedings
1862-4405
2007-02-07
6421
1
2
10.4230/DagSemProc.06421.2
article
06421 Executive Summary – Robot Navigation
Fekete, Sándor
Fleischer, Rudolf
Klein, Rolf
Lopez-Ortiz, Alejandro
For quite a number of years, researchers from various fields have studied problems motivated by Robot Navigation. People in Online Algorithms have developed strategies that can deal with the inherent lack of information an autonomous robot encounters, as it sets out to perform a task in an unknown environment. Computational Geometers have obtained many results on the efficient planning of collision-free motions, and on visibility problems. Scientists and engineers in Robotics have perfected real robots to an astounding degree. Economic household robots and artificial pets are now available; more complex robots are able to carry out difficult search-and-rescue and exploration missions.
The goal of this seminar is to bring together researchers from robotics, computational geometry, and online algorithms, in order to exchange problems and ideas, and to jointly work towards solutions. The following questions seem crucial. Given the advanced level of technical development, what are the strategic planning problems researchers in robotics need to solve in the next decade? How can real environments and robots be modeled, so that planning problems become tractable by algorithmic methods, and solutions are still significant for applications? In particular, what can be assumed about perception and motion accuracy?
We are planning for plenary sessions where members of all groups can present their problems and recent work. In addition, there will be plenty of time for discussions.
https://drops.dagstuhl.de/storage/16dagstuhl-seminar-proceedings/dsp-vol06421/DagSemProc.06421.2/DagSemProc.06421.2.pdf
Motion planning
robotics
computational geometry
online algorithms
eng
Schloss Dagstuhl – Leibniz-Zentrum für Informatik
Dagstuhl Seminar Proceedings
1862-4405
2007-02-07
6421
1
12
10.4230/DagSemProc.06421.3
article
6D SLAM with Cached kd-tree Search
Nüchter, Andreas
Lingemann, Kai
Hertzberg, Joachim
6D SLAM (Simultaneous Localization and Mapping) or 6D Concurrent
Localization and Mapping of mobile robots considers six degrees of
freedom for the robot pose, namely, the x, y and z coordinates
and the roll, yaw and pitch angles. In previous work we presented our
scan matching based 6D SLAM approach, where scan matching is
based on the well known iterative closest point (ICP) algorithm
[Besl 1992]. Efficient implementations of this algorithm are a
result of a fast computation of closest points. The usual approach,
i.e., using kd-trees is extended in this paper. We describe a novel
search stategy, that leads to significant speed-ups. Our mapping
system is real-time capable, i.e., 3D maps are computed using the
resources of the used Kurt3D robotic hardware.
https://drops.dagstuhl.de/storage/16dagstuhl-seminar-proceedings/dsp-vol06421/DagSemProc.06421.3/DagSemProc.06421.3.pdf
SLAM
kd tree search
eng
Schloss Dagstuhl – Leibniz-Zentrum für Informatik
Dagstuhl Seminar Proceedings
1862-4405
2007-02-07
6421
1
0
10.4230/DagSemProc.06421.4
article
Adaptive Analysis of On-line Algorithms
Dorrigiv, Reza
Lopez-Ortiz, Alejandro
On-line algorithms are usually analyzed using competitive analysis, in which the performance
of on-line algorithm on a sequence is normalized by the performance of the optimal on-line
algorithm on that sequence. In this paper we introduce adaptive/cooperative analysis as an
alternative general framework for the analysis of on-line algorithms. This model gives promising
results when applied to two well known on-line problems, paging and list update. The idea is
to normalize the performance of an on-line algorithm by a measure other than the performance
of the on-line optimal algorithm OPT. We show that in many instances the perform of OPT
on a sequence is a coarse approximation of the difficulty or complexity of a given input. Using
a finer, more natural measure we can separate paging and list update algorithms which were
otherwise undistinguishable under the classical model. This createas a performance hierarchy of
algorithms which better reflects the intuitive relative strengths between them. Lastly, we show
that, surprisingly, certain randomized algorithms which are superior to MTF in the classical
model are not so in the adaptive case. This confirms that the ability of the on-line adaptive
algorithm to ignore pathological worst cases can lead to algorithms that are more efficient in
practice.
https://drops.dagstuhl.de/storage/16dagstuhl-seminar-proceedings/dsp-vol06421/DagSemProc.06421.4/DagSemProc.06421.4.pdf
On-line algorithms
paging
adaptive/cooperative analysis
eng
Schloss Dagstuhl – Leibniz-Zentrum für Informatik
Dagstuhl Seminar Proceedings
1862-4405
2007-02-07
6421
1
19
10.4230/DagSemProc.06421.5
article
Competitive Online Searching for a Ray in the Plane
Eubeler, Andrea
Fleischer, Rudolf
Kamphans, Tom
Klein, Rolf
Langetepe, Elmar
Trippen, Gerhard
We consider the problem of a searcher that looks, for example, for a lost flashlight in a dusty environment. The searcher finds the flashlight as soon as it crosses the ray emanating from the flashlight. In order to pick it up, the searcher moves to the origin of the light beam. We compare the length of the path of the searcher to the shortest path to the goal.
First, we give a search strategy for a special case of the ray search---the window shopper problem---,
where the ray we are looking for is perpendicular to a known ray. Our strategy achieves a competitive factor of $1.059ldots$, which is optimal. Then, we consider rays in arbitrary position in the plane. We present an online strategy that achieves a factor of $22.513ldots$, and give a lower bound of $2pi,e=17.079ldots$.
https://drops.dagstuhl.de/storage/16dagstuhl-seminar-proceedings/dsp-vol06421/DagSemProc.06421.5/DagSemProc.06421.5.pdf
Online motion planning
competitive analysis
ray search
eng
Schloss Dagstuhl – Leibniz-Zentrum für Informatik
Dagstuhl Seminar Proceedings
1862-4405
2007-02-07
6421
1
4
10.4230/DagSemProc.06421.6
article
Computing Shortest Safe Path amidst Growing Discs in the Plane
van den Berg, Jur
Overmars, Mark
In this paper we discuss the problem of planning safe paths amidst unpredictably moving obstacles in the plane. Given the initial positions and the maximal velocities of the moving obstacles, the regions that are possibly not collision-free are modeled by discs that grow over time. We present an approach to compute the shortest path between two points in the plane that avoids these growing discs. The generated paths are thus guaranteed to be collision-free with respect to the moving obstacles while being executed. We created a fast implementation that is capable of planning paths amidst many growing discs within milliseconds.
https://drops.dagstuhl.de/storage/16dagstuhl-seminar-proceedings/dsp-vol06421/DagSemProc.06421.6/DagSemProc.06421.6.pdf
Path planning dynamic environments
eng
Schloss Dagstuhl – Leibniz-Zentrum für Informatik
Dagstuhl Seminar Proceedings
1862-4405
2007-02-07
6421
1
18
10.4230/DagSemProc.06421.7
article
Extracting Visibility Information by Following Walls
Yershova, Anna
Tovar, Benjamin
LaValle, Steven M.
This paper presents an analysis of a simple robot model, called Bitbot. The Bitbot has limited capabilities; it can reliably follow walls and sense a contact
with a wall. Although the Bitbot does not have a range sensor or a camera, it is able to acquire visibility information from the environment, which is then used to solve a pursuit-evasion task. Our developments are centered on the characterization of the information the Bitbot acquires. At any given moment, due to the sensing uncertainty, the robot does not know the current state. In general, uncertainty in the state is one of the central issues in robotics; the Bitbot model serves as an example of how the notion of information space naturally handles uncertainty. We show that state estimation with the Bitbot is a challenging problem, related to the well-known open problem of characterizing visibility graphs in computational
geometry. However, state estimation becomes unnecessary to the achievement of the Bitbot's visibility tasks. We show how pursuit-evasion strategy is derived from a careful manipulation with histories of observations, and present analysis of the algorithm and experimental results.
https://drops.dagstuhl.de/storage/16dagstuhl-seminar-proceedings/dsp-vol06421/DagSemProc.06421.7/DagSemProc.06421.7.pdf
Planning
localization
pursuit evasion
visibility
eng
Schloss Dagstuhl – Leibniz-Zentrum für Informatik
Dagstuhl Seminar Proceedings
1862-4405
2007-02-07
6421
1
23
10.4230/DagSemProc.06421.8
article
Polygon Exploration with Discrete Vision
Fekete, Sándor
Schmidt, Christiane
With the advent of autonomous robots with two- and
three-dimensional scanning capabilities, classical visibility-based
exploration methods from computational geometry have gained in
practical importance. However, real-life laser scanning of useful
accuracy does not allow the robot to scan continuously while in
motion; instead, it has to stop each time it surveys its
environment. This requirement was studied by Fekete, Klein and
N"uchter for the subproblem of looking around a corner, but until
now has not been considered for whole polygonal regions.
We give the first comprehensive algorithmic study for this important
algorithmic problem that combines stationary art gallery-type
aspects with watchman-type issues in an online scenario. We show
that there is a lower bound of $Omega(sqrt{n})$ on the competitive
ratio in an orthogonal polygon with holes; we also demonstrate that
even for orthoconvex polygons, a competitive strategy can only be
achieved for limited aspect ratio $A$, i.e., for a given lower bound
on the size of an edge. Our main result is an $O(log
A)$-competitive strategy for simple rectilinear polygons, which is
best possible up to constants.
https://drops.dagstuhl.de/storage/16dagstuhl-seminar-proceedings/dsp-vol06421/DagSemProc.06421.8/DagSemProc.06421.8.pdf
Searching
scan cost
visibility problems
watchman problems
online searching
competitive strategies
autonomous mobile robots.