2 research outputs found
The Dynamical Nightwatch's Problem Solved by the Autonomous Micro-Robot Khepera
Löffler A, Klahold J, Rückert U. The Dynamical Nightwatch's Problem Solved by the Autonomous Micro-Robot Khepera. In: Hao J-K, Lutton E, Ronald E, Schoenauer M, Snyers D, eds. Selected Papers of the 3rd European Conference on Artificial Evolution (AE97). Vol 1363. Nimes, France: Springer-Verlag; 1998: 303-313.In this paper, we present the implementation, both in a simulator
and in a real-robot version, of an efficient solution to the so-called
dynamical nightwatch’s problem on the micro-robot Khepera. The problem
consists mainly in exploring a previously unknown environment while
detecting, registering and recognizing light sources which may dynamically
be turned on and off. At the end of each round a report is requested
from the robot. Therein we made use of an agent-based approach and
applied a self-organizing feature map in order to refine some of the behaviour
generating control-modules
Decision tree learning for intelligent mobile robot navigation
The replication of human intelligence, learning and reasoning by means of computer
algorithms is termed Artificial Intelligence (Al) and the interaction of such
algorithms with the physical world can be achieved using robotics. The work described in
this thesis investigates the applications of concept learning (an approach which takes its
inspiration from biological motivations and from survival instincts in particular) to robot
control and path planning. The methodology of concept learning has been applied using
learning decision trees (DTs) which induce domain knowledge from a finite set of training
vectors which in turn describe systematically a physical entity and are used to train a robot
to learn new concepts and to adapt its behaviour.
To achieve behaviour learning, this work introduces the novel approach of hierarchical
learning and knowledge decomposition to the frame of the reactive robot architecture.
Following the analogy with survival instincts, the robot is first taught how to survive in
very simple and homogeneous environments, namely a world without any disturbances or
any kind of "hostility". Once this simple behaviour, named a primitive, has been established, the robot is trained to adapt new knowledge to cope with increasingly complex
environments by adding further worlds to its existing knowledge. The repertoire of the
robot behaviours in the form of symbolic knowledge is retained in a hierarchy of clustered
decision trees (DTs) accommodating a number of primitives. To classify robot perceptions,
control rules are synthesised using symbolic knowledge derived from searching the
hierarchy of DTs.
A second novel concept is introduced, namely that of multi-dimensional fuzzy associative
memories (MDFAMs). These are clustered fuzzy decision trees (FDTs) which are trained
locally and accommodate specific perceptual knowledge. Fuzzy logic is incorporated to
deal with inherent noise in sensory data and to merge conflicting behaviours of the DTs.
In this thesis, the feasibility of the developed techniques is illustrated in the robot
applications, their benefits and drawbacks are discussed