Full Text Available
Note: Clicking the button above will open the full text document at the original institutional repository in a new window.
Vision-based control of an unknown suspended payload with a multirotor Unmanned Aerial Vehicle
Thesis (MEng)--Stellenbosch University, 2021.
Saved in:
| Main Author: | |
|---|---|
| Other Authors: | |
| Format: | Thesis |
| Language: | en_ZA |
| Published: |
Stellenbosch : Stellenbosch University
2021
|
| Subjects: | |
| Tags: |
No Tags, Be the first to tag this record!
|
| _version_ | 1867613841663197184 |
|---|---|
| access_status_str | Open Access |
| author | Slabber, Francois |
| author2 | Jordaan, Hendrik Willem |
| author_browse | Jordaan, Hendrik Willem Slabber, Francois |
| author_facet | Jordaan, Hendrik Willem Slabber, Francois |
| author_sort | Slabber, Francois |
| collection | Thesis |
| dc_rights_str_mv | Stellenbosch University |
| description | Thesis (MEng)--Stellenbosch University, 2021. |
| format | Thesis |
| id | oai:scholar.sun.ac.za:10019.1/109798 |
| institution | Stellenbosch University (South Africa) |
| language | en_ZA |
| last_indexed | 2026-06-10T12:42:33.557Z |
| license_str | Other — see source repository |
| provenance_str_mv | Harvested via OAI-PMH from SUNScholar — Stellenbosch University Repository |
| publishDate | 2021 |
| publishDateRange | 2021 |
| publishDateSort | 2021 |
| publisher | Stellenbosch : Stellenbosch University |
| publisherStr | Stellenbosch : Stellenbosch University |
| record_format | dspace |
| source_str | SUNScholar — Stellenbosch University Repository |
| spelling | oai:scholar.sun.ac.za:10019.1/109798 Vision-based control of an unknown suspended payload with a multirotor Unmanned Aerial Vehicle Slabber, Francois Jordaan, Hendrik Willem Stellenbosch University. Faculty of Engineering. Dept. of Electrical and Electronic Engineering. Vision-Based Control UCTD UAVs (Unmanned aerial vehicles) Airplanes -- Control systems Payloads (Aerospace engineering) Quadrotor helicopters Thesis (MEng)--Stellenbosch University, 2021. ENGLISH ABSTRACT: n this thesis, a flight control system for a quadrotor transporting an unknown suspendedpayload is proposed. The suspended payload parameters, which include its mass and cablelength, are unknown and direct measurements of its states are not available. The swingingmotion of the suspended payload negatively affects the flight dynamics of the quadrotor. Avision-based control strategy is designed and verified in simulation to damp the swingingmotion of the payload and ensure stable flight.A feedforward-feedback adaptive control strategy is proposed that consists of a notch filterand Linear Quadratic Gaussian (LQG) controller with integral action. The control strategyadapts to the specific payload by estimating the unknown payload parameters. The notchfilter serves as an input shaper to generate trajectories that suppress the generation ofoscillations of the suspended payload while the LQG controller simultaneously control thequadrotor and suspended payload to actively damp the payload oscillations. A vision-based state estimator is designed to provide payload state estimates for theoptimal full-state feedback controller. A downward facing camera is attached to thebottom of the quadrotor to provide an Extended Kalman Filter (EKF) with swing anglemeasurements. A motion-based object detection algorithm is used to detect the suspendedpayload. This approach is taken to design a vision system that is independent of visualmarkers and can detect any arbitrary suspended payload attached to the quadrotor.The proposed control strategy was implemented in the PX4 flight control stack and RobotOperating System (ROS) was used for the vision system. Software-in-the-loop (SITL)and hardware-in-the-loop (HITL) simulations were performed in the PX4 and Gazebosimulation environment to verify the proposed control strategy. The simulation resultsproved that the proposed vision-based control strategy is able to estimate the unknownpayload parameters with good accuracy and use these estimates to adapt to differentsuspended payloads. The vision-based state estimator is able to provide accurate stateestimates for full-state feedback control and the feedforward-feedback controller is able todamp the unwanted payload oscillations and ensure stable flight. The proposed controlstrategy is proved to be practically feasible and can be verified in practical flight tests. AFRIKAANSE OPSOMMING: Hierdie tesis stel ’n vlugbeheerstelsel voor vir ’n vierrotor onbemande vliegtuig met ’nonbekende swaaiende loonvrag. Die loonvragparameters, wat die massa en kabellengteinsluit, is onbekend en direkte metings van die swaaihoeke is nie moontlik nie. Dieswaaibeweging van die loonvrag het ’n negatiewe effek op die vlugdinamika van dievierrotor vliegtuig. ’n Visie-gebaseerde beheerstrategie is ontwerp om die swaaibewegingvan die loonvrag te demp en stabiele vlug te verseker. Die beheerstrategie is geverifieer insimulasie.’n Aanpasbare vorentoevoer-terugvoer beheerstrategie wat bestaan uit ’n kerffilter (band-blokkeringsfilter) en ’n Lineˆere Kwadratiese Gaussiese (LKG) beheerder word voorgestel.Die beheerstrategie skat die onbekende loonvragparameters af en gebruik die afskattings omaan te pas by die spesifieke loonvrag. Die kerffilter dien as ’n trajekbeplanner wat trajektegenereer om die ossilasies van die loonvrag te onderdruk, terwyl die LKG-beheerder dievierrotor voertuig en loonvrag gelyktydig beheer om die swaaibewegings van die loonvragte demp. ’n Visie-gebaseerde toestandafskatter is ontwerp om die swaaihoek toestande van dieloonvrag af te skat vir die optimale terugvoerbeheerder. ’n Kamera wat aan die onderkantvan die vierrotor voertuig geplaas is word gebruik om swaaihoekmates te neem wat gebruikword in die toetstandafskatter. Die visiestelsel maak gebruik van ’n bewegingsgebaseerdealgoritme om die loonvrag op te tel. Sodoende is die visiestelsel onafhanklik van diegebruik van visuele merkers vir die optel van die loonvrag en kan die visiestelsel toegepasword vir enige arbitrˆere loonvrag wat gekoppel word aan die vierrotor voertuig.Die voorgestelde beheerstrategie is ge ̈ımplementeer in die PX4 beheerargitektuur en dieROS sagteware is gebruik vir die implementasie van die visiestelsel. Sagteware-in-die-lusen hardeware-in-die-lus simulasies is uitgevoer in die PX4 en Gazebo simulasie omgewingom die voorgestelde beheerstrategie te verifieer. Die simulasies het bevestig dat dievoorgestelde visie-gebaseerde beheerstrategie die onbekende loonvragparameters met goeieakkuraatheid kan afskat en hierdie afskattings gebruik om aan te pas by die verskillendeloonvragte. Die simulasies het ook bevestig dat die visie-gebaseerde toestandafskatterdie swaaihoek toestande van die loonvrag akkuraat kan afskat en dat die vorentoevoer-terugvoer beheerstrategie die ongewenste loonvrag ossilasies effektief kan demp en stabielevlug verseker. Dit is bewys dat die voorgestelde beheerstrategie prakties uitvoerbaar is enkan dus geverifieer word in praktiese vlugtoetse. Masters 2021-01-27T09:25:17Z 2021-04-21T14:26:36Z 2021-01-27T09:25:17Z 2021-04-21T14:26:36Z 2021-03 Thesis http://hdl.handle.net/10019.1/109798 en_ZA Stellenbosch University 115 pages application/pdf Stellenbosch : Stellenbosch University |
| spellingShingle | Vision-Based Control UCTD UAVs (Unmanned aerial vehicles) Airplanes -- Control systems Payloads (Aerospace engineering) Quadrotor helicopters Slabber, Francois Vision-based control of an unknown suspended payload with a multirotor Unmanned Aerial Vehicle |
| title | Vision-based control of an unknown suspended payload with a multirotor Unmanned Aerial Vehicle |
| title_full | Vision-based control of an unknown suspended payload with a multirotor Unmanned Aerial Vehicle |
| title_fullStr | Vision-based control of an unknown suspended payload with a multirotor Unmanned Aerial Vehicle |
| title_full_unstemmed | Vision-based control of an unknown suspended payload with a multirotor Unmanned Aerial Vehicle |
| title_short | Vision-based control of an unknown suspended payload with a multirotor Unmanned Aerial Vehicle |
| title_sort | vision based control of an unknown suspended payload with a multirotor unmanned aerial vehicle |
| topic | Vision-Based Control UCTD UAVs (Unmanned aerial vehicles) Airplanes -- Control systems Payloads (Aerospace engineering) Quadrotor helicopters |
| url | http://hdl.handle.net/10019.1/109798 |
| work_keys_str_mv | AT slabberfrancois visionbasedcontrolofanunknownsuspendedpayloadwithamultirotorunmannedaerialvehicle |