Publication
Verfahren zur Vermeidung von Kollisionen gesteuert beweglicher Teile einer Anlage
Udo Frese; Holger Täubig
DFKI, DFKI Research Reports (RR), Vol. 09-01, 2009.
Abstract
This technical report describes the collsion avoidance method "Verfahren zur Vermeidung von Kollisionen gesteuert beweglicher Teile einer Anlage" as applied for a patent by the German Research Center for Artificial Intelligence under No. 102009006256.4-32.
The method allows to centrally monitor moveable parts of a machine (e.g. robot arms or vehicles) and so avoids collisions among the machine parts or with the environment. For this it can be used with or without additional sensorial perception of the environment.
A basic idea of the described method is representing the volume touched by one part of a machine while its movement as the convex hull of a finite set of points expanded by a buffer radius. This representation is robust, real-time computable, and does not have numerical difficulties.
The representation is computed for all involved parts of the machine. Afterwards all relevant pairs of volumes, or the sensed environment respectively, are checked for collisions. To do this, a new real-time algorithm is presented.
All computations performed by the method are conservative approximations, which results in the system as a whole being safe in a strict mathematical sense.
The technical report offers a couple of versions for these conservative approximations. With this set of approximations the user is enabled to trade a more exact model of his machine against a more easier and faster one.
Concerning vehicle trajectories (e.g. braking trajectories) the usage of a new configuration space is described also.
Its main advantage is a joint modeling of straight and circular trajectories and even turning on the spot without singularities, which for instance occur with radius or curvature as parameter.