4 research outputs found
Mobile robot vavigation using a vision based approach
PhD ThesisThis study addresses the issue of vision based mobile robot navigation in a partially
cluttered indoor environment using a mapless navigation strategy. The work focuses on
two key problems, namely vision based obstacle avoidance and vision based reactive
navigation strategy.
The estimation of optical flow plays a key role in vision based obstacle avoidance
problems, however the current view is that this technique is too sensitive to noise and
distortion under real conditions. Accordingly, practical applications in real time robotics
remain scarce. This dissertation presents a novel methodology for vision based obstacle
avoidance, using a hybrid architecture. This integrates an appearance-based obstacle
detection method into an optical flow architecture based upon a behavioural control
strategy that includes a new arbitration module. This enhances the overall performance
of conventional optical flow based navigation systems, enabling a robot to successfully
move around without experiencing collisions.
Behaviour based approaches have become the dominant methodologies for designing
control strategies for robot navigation. Two different behaviour based navigation
architectures have been proposed for the second problem, using monocular vision as the
primary sensor and equipped with a 2-D range finder. Both utilize an accelerated
version of the Scale Invariant Feature Transform (SIFT) algorithm. The first
architecture employs a qualitative-based control algorithm to steer the robot towards a
goal whilst avoiding obstacles, whereas the second employs an intelligent control
framework. This allows the components of soft computing to be integrated into the
proposed SIFT-based navigation architecture, conserving the same set of behaviours
and system structure of the previously defined architecture. The intelligent framework
incorporates a novel distance estimation technique using the scale parameters obtained
from the SIFT algorithm. The technique employs scale parameters and a corresponding
zooming factor as inputs to train a neural network which results in the determination of
physical distance. Furthermore a fuzzy controller is designed and integrated into this
framework so as to estimate linear velocity, and a neural network based solution is
adopted to estimate the steering direction of the robot. As a result, this intelligent
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approach allows the robot to successfully complete its task in a smooth and robust
manner without experiencing collision.
MS Robotics Studio software was used to simulate the systems, and a modified Pioneer
3-DX mobile robot was used for real-time implementation. Several realistic scenarios
were developed and comprehensive experiments conducted to evaluate the performance
of the proposed navigation systems.
KEY WORDS: Mobile robot navigation using vision, Mapless navigation, Mobile
robot architecture, Distance estimation, Vision for obstacle avoidance, Scale Invariant
Feature Transforms, Intelligent framework