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Extremum-seeking control for constrained optimal formation flight of commercial airliners
Thesis (MScEng)--Stellenbosch University, 2018.
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| Format: | Thesis |
| Language: | en_ZA |
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Stellenbosch : Stellenbosch University
2018
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| _version_ | 1867614025198600192 |
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| access_status_str | Open Access |
| author | Van Zyl, Izaak |
| author2 | Engelbrecht, J. A. A. |
| author_browse | Engelbrecht, J. A. A. Van Zyl, Izaak |
| author_facet | Engelbrecht, J. A. A. Van Zyl, Izaak |
| author_sort | Van Zyl, Izaak |
| collection | Thesis |
| dc_rights_str_mv | Stellenbosch University |
| description | Thesis (MScEng)--Stellenbosch University, 2018. |
| format | Thesis |
| id | oai:scholar.sun.ac.za:10019.1/103603 |
| institution | Stellenbosch University (South Africa) |
| language | en_ZA |
| last_indexed | 2026-06-10T12:45:28.762Z |
| license_str | Other — see source repository |
| provenance_str_mv | Harvested via OAI-PMH from SUNScholar — Stellenbosch University Repository |
| publishDate | 2018 |
| publishDateRange | 2018 |
| publishDateSort | 2018 |
| publisher | Stellenbosch : Stellenbosch University |
| publisherStr | Stellenbosch : Stellenbosch University |
| record_format | dspace |
| source_str | SUNScholar — Stellenbosch University Repository |
| spelling | oai:scholar.sun.ac.za:10019.1/103603 Extremum-seeking control for constrained optimal formation flight of commercial airliners Van Zyl, Izaak Engelbrecht, J. A. A. Stellenbosch University. Faculty of Engineering. Dept. of Electrical and Electronic Engineering. Aeronautics, Commercial UCTD Extremum principles Formation flying Airlines Thesis (MScEng)--Stellenbosch University, 2018. ENGLISH ABSTRACT: Formation flight of commercial airliners has become a topic of interest due to the possibility of significant fuel savings. With air traffic rapidly increasing, the aeronautical industry recognizes the necessity to improve fuel efficiency of long distance ights. Previous studies have shown that extended formation flight of existing commercial aircraft is plausible, but have not dedicated much attention to fully utilising the wingtip generated wakes. This study presents the design, implementation, and verification of a perturbation-based extremum-seeking controller that enables follower aircraft to locate and maintain optimal formation separations in a practical formation flight scenario. Typically, the trailing vortices of the leader aircraft are displaced due to atmospheric disturbances, such as static winds and turbulence, and models of the vortex positions are not exact. Due to the dangers related to flight deep in the leader's wake, a novel constrained objective function is proposed that prevents the extremum-seeking controller from guiding the follower aircraft too close to the vortex core. In this constrained objective function, the extremum is represented by a constrained extremum contour instead of a single point. A novel extremum-seeking state machine is proposed that controls the different modes of operation that the follower aircraft transitions through as it approaches the constrained extremum. The states and the state transition boundaries are defined as functions of the objective function, which allow them to follow the displaced trailing vortex, instead of remaining static relative to the leader aircraft. This also enables the extremum-seeking control to not only track a static trailing vortex, but also a constrained extremum for a dynamic trailing vortex. It is also shown that by approaching the constrained extremum at a constant approach rate, rather than the classical proportional approach rate, the effects of the non-linear wake on the seeking performance may be mitigated. The extremum-seeking controller was verified in simulation on a formation flight model of two Boeing 747 aircraft in right echelon formation. The formation is subjected to realistic atmospheric disturbances and sensor noise. The simulation results show that the extremumseeking controller is able to successfully guide the follower to the constrained extremum, even in the presence of varying static wind and light turbulence, and that thrust reductions of up to 23% may be achieved. AFRIKAANSE OPSOMMING: Formasie vlug van kommersiële vliegtuie kry baie belangstelling vanweë die moontlikheid van aansienlike brandstofbesparings. Met lugverkeer wat vinnig aan die toeneem is, erken die lugvaartbedryf die noodsaaklikheid om die brandstofdoeltreffendheid van langafstandvlugte te verbeter. Vorige studies het getoon dat uitgebreide formasie vlug van bestaande kommersiële vliegtuie wel moontlik is, maar het nie veel aandag geskenk om die vlerkpunt-gegenereerde volgstroom van die leier vliegtuig ten volle te benut nie. Hierdie studie beskryf die ontwerp, implementering en verifikasie van 'n storing-gebaseerde ekstremum-soekende beheerder wat volger vliegtuie in staat stel om die optimale ligging in die formasie op te spoor en te volg in 'n realistiese formasie vlug scenario. Tipies word die volgstroom van die leiervliegtuig verplaas weens atmosferiese steurnisse soos statiese winde en turbulensie. As gevolg van die gevare van te diep vlieg in die leier vliegtuig se volgstroom, word 'n nuwe beperkte doelfunksie voorgestel wat die ekstremum-soekende beheerder verhoed om die volger vliegtuig te naby aan die kern van die leier se draaikolk te laat kom. In hierdie beperkte doelfunksie word die ekstremum verteenwoordig deur 'n beperkte ekstremum kontoer, in plaas van 'n enkele punt. 'n Ekstremum-soekende toestandsmasjien word voorgestel wat die verskillende operasie modusse van die volger vliegtuig beheer soos wat dit die beperkte ekstremum nader. Die toestande en oorgangsgrense van die toestandsmasjien word gedefinieer as funksies van die doelfunksie, wat hulle in staat stel om saam met die verplaasde volgstroom te beweeg, in plaas daarvan om staties te bly ten opsigte van die leiervliegtuig. Dit stel ook die ekstremum-soekende beheerder in staat om 'n beperkte ekstremum vir 'n dinamiese volgstroom te volg, en nie net vir 'n statiese volgstroom nie. Dit word ook getoon dat die effek van die nie-line^ere volgstroom op die verrigting van die ekstremum soek beheerder beperk kan word deur die beperkte ekstremum teen 'n konstante spoed te benader, eerder as teen 'n spoed wat proporsioneel is aan die gradient van die doel funksie. Die ekstremum-soek beheerder is geverifieer in simulasie op 'n formasievlugmodel van twee Boeing 747-vliegtuie in regsgerigte-echelon-formasie. Die formasie word onderwerp aan realistiese atmosferiese steurnisse en sensor ruis. Die simulasie resultate toon dat die ekstremum-soekende beheerder in staat is om die volger na die beperkte ekstremum te lei, selfs in die teenwoordigheid van wisselende statiese wind en ligte turbulensie, en dat enjin stukrag verlagings van tot 23% verkry kan word. 2018-02-26T06:25:53Z 2018-04-09T07:03:30Z 2018-02-26T06:25:53Z 2018-04-09T07:03:30Z 2018-03 Thesis http://hdl.handle.net/10019.1/103603 en_ZA Stellenbosch University 204 pages : illustrations application/pdf Stellenbosch : Stellenbosch University |
| spellingShingle | Aeronautics, Commercial UCTD Extremum principles Formation flying Airlines Van Zyl, Izaak Extremum-seeking control for constrained optimal formation flight of commercial airliners |
| title | Extremum-seeking control for constrained optimal formation flight of commercial airliners |
| title_full | Extremum-seeking control for constrained optimal formation flight of commercial airliners |
| title_fullStr | Extremum-seeking control for constrained optimal formation flight of commercial airliners |
| title_full_unstemmed | Extremum-seeking control for constrained optimal formation flight of commercial airliners |
| title_short | Extremum-seeking control for constrained optimal formation flight of commercial airliners |
| title_sort | extremum seeking control for constrained optimal formation flight of commercial airliners |
| topic | Aeronautics, Commercial UCTD Extremum principles Formation flying Airlines |
| url | http://hdl.handle.net/10019.1/103603 |
| work_keys_str_mv | AT vanzylizaak extremumseekingcontrolforconstrainedoptimalformationflightofcommercialairliners |