Authors:
Michael Brunner
;
Bernd Brüeggemann
and
Dirk Schulz
Affiliation:
Fraunhofer Institute for Communication and Information Processing and Ergonomics FKIE, Germany
Keyword(s):
Metric, Traversability, Obstacle, Rough Terrain, Reconfigurable Chassis, Motion Planning, Mobile Robot, Autonomy.
Related
Ontology
Subjects/Areas/Topics:
Autonomous Agents
;
Informatics in Control, Automation and Robotics
;
Mobile Robots and Autonomous Systems
;
Robotics and Automation
Abstract:
The fixed chassis design of commonly employed mobile robots restricts their application to fairly flat environments,
as the wheel diameters or the track heights impose hard limits on their mobility. Unstructured outdoor
and urban environments alike comprehend many different invincible obstacles for most of those systems, like
stairs, boulders or rubble. However, there are mobile robots with reconfigurable chassis providing a higher
degree of mobility and enabling them to overcome such obstacles. Yet, current planning algorithms rarely exploit
those enhanced capabilities, limiting these systems to the same environments as the fixed chassis robots.
This paper focuses on the metrics used by our motion planner. The employment of a two-stage planning approach
allows us to use different cost functions for the initial path search and the detailed motion planning
step. The purpose of the initial search is to quickly find a fast environment-driven path to the goal. Hence,
it uses fast computa
ble heuristics to assess the drivability, i.e. a risk quantification and the utmost operation
limits of the robot model. The detailed planning step determines the desired robot configurations. For this
purpose, we consider the actuator controls, the system’s stability, an estimate of the traction, and the driving
speed in addition to the quantities used in the first stage.
We present experiments to illustrate the influence of the safety weights and real world experiments which
prove the validity and feasibility of the metrics used by our motion planning algorithm.
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