Thesis (MScEng (Electrical and Electronic Engineering))--University of Stellenbosch, 2010. / ENGLISH ABSTRACT: In recent years, the use of airships has become popular for observation purposes since they provide
a cost effective alternative to other aircraft. For this project a lateral and longitudinal flight control
system are required for waypoint navigation flight of an 8m long, non-rigid airship. The airship’s
actuators include a rudder, elevator and a propulsion system which can be vectored longitudinally.
Two airship models are evaluated for this project. A chosen model is linearised and a modal
analysis is done. The modal analysis is compared to a previous modal study done on the YEZ-2A
airship and is found to compare well. Each airship mode is discussed and the linear behaviour is
compared to the behaviour of the non-linear model.
A fuzzy logic controller design approach was undertaken for the design of speed, heading and
height controllers. These non-linear controllers were designed for the non-linear model, due to the
following reasons:
Fuzzy logic controllers show tolerance to model inaccuracies.
Complexity of design is simple.
Controllers can be adjusted intuitively.
Fuzzy logic controllers can be combined with conventional control techniques.
Simulation results showed adequate lateral and longitudinal performance, even when subjected
to light wind conditions and disturbances.
The inertial measuring unit implemented in a previous project is used and additional hardware
is designed and implemented for the control of the airship’s actuators. Several improvements are
made to the groundstation software to allow for activation of different controllers as well as for
setting up the desired flight plan.
The controller performance is tested through flight tests and shows adequate performance as
well as controller potential. Although further work is still required for improving the controllers’
performance, this thesis acts as a platform for future research. / AFRIKAANSE OPSOMMING: In die afgelope paar jaar het die gebruik van die lugskepe gewild geword vir waarnemings doeleindes
aangesien dit ’n koste effektiewe alternatief vir ander lugvaartuie bied. In hierdie projek word ’n
laterale en longitudinale beheerstelsel benodig vir merker navigasie vlugte met ’n 8m lang, nierigiede
lugskip. Die lugskip se aktueerders sluit in ’n rigtingroer, hoogteroer asook ’n aandrywing
stelsel wat oorlangs gestuur kan word.
Vir hierdie projek is twee lugskip modelle geïmplementeer. Die gekose model is gelineariseer
en ’n modale analise is gedoen. Die modale analise is met ’n vorige modale studie vir die YEZ-2A
lugskip vergelyk en wys soortegelyke linieêre gedrag. Die lugskip modusse is bespreek en die linieêre
gedrag word met die gedrag van die nie-linieêre model vergelyk.
Daar is op ’n fuzzy logiese beheerder ontwerp besluit vir die ontwerp van spoed, rigting en hoogte
beheerders. Hierdie nie-linieêre beheerders is ontwerp vir die nie-linieêre model a.g.v. die volgende
redes:
Fuzzy logiese beheerders toon toleransie vir modellering of meetfoute.
Kompleksiteit van die ontwerp is eenvoudig.
Beheerders kan intuïtief aangepas word.
Fuzzy logiese beheerders kan met konvensionele beheertegnieke gekombineer word.
Simulasie resultate toon voldoende werkverrigtinge, selfs in die teenwoordigheid van ligte wind
sowel as ander versteurings.
Die inersiële metings eenheid, wat geïmplementeer is in ’n vorige projek, is gebruik en addisionele
hardeware vir die beheer van die lugskip is aktueerders is ontwerp en geïmplementeer. Talle
verbeterings is aangebring aan die grondstasie sagteware vir die aktiveer van die beheerders sowel
as die uitleg van die gekose vlugplan.
Die beheerders se werksverrigtinge is getoets gedurende vlugtoetse en toon voldoende beheer
vermoë sowel as beheerder potensiaal. Alhoewel verdere werk steeds nodig is vir die verbetering
van die beheerders, dien hierdie tesis as ’n platform vir toekomstige navorsing.
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:sun/oai:scholar.sun.ac.za:10019.1/4090 |
| Date | 03 1900 |
| Creators | Avenant, Gerrit Christiaan |
| Contributors | Steyn, W. H., 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 | English |
| Detected Language | Unknown |
| Type | Thesis |
| Format | 113 p. : ill. |
| Rights | University of Stellenbosch |
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