Thesis (MScEng (Electrical and Electronic Engineering))--University of Stellenbosch, 2011. / ENGLISH ABSTRACT: This thesis presents work completed on the design of control and vision components
for use in a monocular vision-based human-following robot. The use
of vision in a controller feedback loop is referred to as vision-based or visual
servo control. Typically, visual servo techniques can be categorised into imagebased
visual servoing and position-based visual servoing. This thesis discusses
each of these approaches, and argues that a position-based visual servo control
approach is more suited to human following.
A position-based visual servo strategy consists of three distinct phases:
target recognition, target pose estimation and controller calculations. The
thesis discusses approaches to each of these phases in detail, and presents a
complete, functioning system combining these approaches for the purposes of
human following.
Traditional approaches to human following typically involve a controller
that causes platforms to navigate directly towards targets, but this work argues
that better following performance can be obtained through the use of a
controller that incorporates target orientation information. Although a purely
direction-based controller, aiming to minimise both orientation and translation
errors, suffers from various limitations, this thesis shows that a hybrid,
gain-scheduling combination of two traditional controllers offers better targetfollowing
performance than its components.
In the case of human following the inclusion of target orientation information
requires that a definition and means of estimating a human’s orientation
be available. This work presents a human orientation measure and experimental
results to show that it is suitable for the purposes of wheeled platform
control. Results of human following using the proposed hybrid, gain-scheduling
controller incorporating this measure are presented to confirm this. / AFRIKAANSE OPSOMMING: Die ontwerp van ’n visiestelsel en beheer-komponente van ’n enkel-kamera robot
vir die volging van mense word hier aangebied. Die gebruik van visuele
terugvoer in die beheerlus word visie-gebaseerde of visuele servobeheer genoem.
Visuele servobeheer tegnieke kan tipies onderskei word tussen beeld-gebaseerde
servobeheer en posisie-gebaseerde visuele servobeheer. Altwee benaderings
word hier bespreek. Die posisie-gebaseerde benadering word aanbeveel vir
die volging van mense.
Die posisie-gebaseerde servobeheertegniek bestaan uit drie duidelike fases:
teiken herkenning, teiken oriëntasie bepaling en die beheerder berekeninge.
Benaderings tot elk van hierdie fases word hier in detail bespreek. Dan word
’n volledige funksionele stelsel aangebied wat hierdie fases saamvoeg sodat
mense gevolg kan word.
Meer tradisionele benaderings tot die volging van mense gebruik tipies ’n
beheerder wat die platvorm direk laat navigeer na die teikens, maar hier word
geargumenteer dat beter werkverrigting verkry kan word deur ’n beheerder
wat die teiken oriëntasie inligting ook gebruik. ’n Suiwer rigting-gebaseerde
beheerder, wat beide oriëntasie en translasie foute minimeer, is onderhewig
aan verskeie beperkings. Hier word egter aangetoon dat ’n hibriede, aanwinsskedulerende
kombinasie van die twee tradisionele beheerders beter teikenvolging
werkverrigting bied as die onderliggende twee tegnieke.
In die geval van die volging van mense vereis die insluiting van teiken oriëntasie
inligting dat ’n definisie van die persoon se oriëntasie beskikbaar is en
dat dit geskat kan word. ’n Oriëntasie maatstaf vir mense word hier aangebied
en dit word eksperimenteel getoon dat dit geskik is om ’n platvorm met
wiele te beheer. Die resultate van die volging van mense wat die voorgestelde
hibriede, aanwins-skedulerende beheerder gebruik, met hierdie maatstaf, word
ter ondersteuning aangebied.
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:sun/oai:scholar.sun.ac.za:10019.1/6813 |
| Date | 03 1900 |
| Creators | Burke, Michael Glen |
| Contributors | Engelbrecht, J. A. A., Brink, W. H., Schreve, K., University of Stellenbosch. Faculty of Engineering. Dept. of Electrical and Electronic Engineering. |
| Publisher | Stellenbosch : University of Stellenbosch |
| Source Sets | South African National ETD Portal |
| Language | en_ZA |
| Detected Language | Unknown |
| Type | Thesis |
| Format | 129 p. : ill. |
| Rights | University of Stellenbosch |
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