31,648 research outputs found
Wavefront Propagation and Fuzzy Based Autonomous Navigation
Path planning and obstacle avoidance are the two major issues in any
navigation system. Wavefront propagation algorithm, as a good path planner, can
be used to determine an optimal path. Obstacle avoidance can be achieved using
possibility theory. Combining these two functions enable a robot to
autonomously navigate to its destination. This paper presents the approach and
results in implementing an autonomous navigation system for an indoor mobile
robot. The system developed is based on a laser sensor used to retrieve data to
update a two dimensional world model of therobot environment. Waypoints in the
path are incorporated into the obstacle avoidance. Features such as ageing of
objects and smooth motion planning are implemented to enhance efficiency and
also to cater for dynamic environments
A neural circuit for navigation inspired by C. elegans Chemotaxis
We develop an artificial neural circuit for contour tracking and navigation
inspired by the chemotaxis of the nematode Caenorhabditis elegans. In order to
harness the computational advantages spiking neural networks promise over their
non-spiking counterparts, we develop a network comprising 7-spiking neurons
with non-plastic synapses which we show is extremely robust in tracking a range
of concentrations. Our worm uses information regarding local temporal gradients
in sodium chloride concentration to decide the instantaneous path for foraging,
exploration and tracking. A key neuron pair in the C. elegans chemotaxis
network is the ASEL & ASER neuron pair, which capture the gradient of
concentration sensed by the worm in their graded membrane potentials. The
primary sensory neurons for our network are a pair of artificial spiking
neurons that function as gradient detectors whose design is adapted from a
computational model of the ASE neuron pair in C. elegans. Simulations show that
our worm is able to detect the set-point with approximately four times higher
probability than the optimal memoryless Levy foraging model. We also show that
our spiking neural network is much more efficient and noise-resilient while
navigating and tracking a contour, as compared to an equivalent non-spiking
network. We demonstrate that our model is extremely robust to noise and with
slight modifications can be used for other practical applications such as
obstacle avoidance. Our network model could also be extended for use in
three-dimensional contour tracking or obstacle avoidance
A reconfigurable hybrid intelligent system for robot navigation
Soft computing has come of age to o er us a wide array of powerful and e cient algorithms
that independently matured and in
uenced our approach to solving problems in robotics,
search and optimisation. The steady progress of technology, however, induced a
ux of new
real-world applications that demand for more robust and adaptive computational paradigms,
tailored speci cally for the problem domain. This gave rise to hybrid intelligent systems, and
to name a few of the successful ones, we have the integration of fuzzy logic, genetic algorithms
and neural networks. As noted in the literature, they are signi cantly more powerful than
individual algorithms, and therefore have been the subject of research activities in the past
decades. There are problems, however, that have not succumbed to traditional hybridisation
approaches, pushing the limits of current intelligent systems design, questioning their solutions
of a guarantee of optimality, real-time execution and self-calibration. This work presents an
improved hybrid solution to the problem of integrated dynamic target pursuit and obstacle
avoidance, comprising of a cascade of fuzzy logic systems, genetic algorithm, the A* search
algorithm and the Voronoi diagram generation algorithm
Application of Biological Learning Theories to Mobile Robot Avoidance and Approach Behaviors
We present a neural network that learns to control approach and avoidance behaviors in a mobile robot using the mechanisms of classical and operant conditioning. Learning, which requires no supervision, takes place as the robot moves around an environment cluttered with obstacles and light sources. The neural network requires no knowledge of the geometry of the robot or of the quality, number or configuration of the robot's sensors. In this article we provide a detailed presentation of the model, and show our results with the Khepera and Pioneer 1 mobile robots.Office of Naval Research (N00014-96-1-0772, N00014-95-1-0409
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