Thesis (MSc)--Stellenbosch University, 2015. / ENGLISH ABSTRACT: With a view to future ship deck landings, a moving platform landing algorithm for an unmanned autonomous helicopter was successfully designed and a number of systems were developed in order to implement the landing algorithm.
Through a combination of an MCA-based ship motion prediction algorithm and the appropriate analysis of platform motion criteria, a system was developed which can identify valid landing opportunities in real ship motion data recorded at sea state 4 for up to 5 s into the future with a 75% success rate.
The bandwidth of the heave motion estimator and controller of the helicopter were increased by the implementation of GPS latency compensation, and velocity and acceleration feed forward terms respectively. The resulting bandwidth of at least 0.2 Hz is sufficient to track the heave motion of a platform which is simulating the motion of a ship at sea state 4 or lower.
After the various systems were integrated they were coordinated in a landing state machine. A stationary platform landing was demonstrated successfully during flight tests, verifying the functionality of the landing state machine and the integration of the system. Landings on a platform simulating the motion of a ship at sea state 4 were demonstrated successfully in hardware-in-the-loop simulations. / AFRIKAANSE OPSOMMING: Met die oog op toekomstige skip dek landings, is 'n bewegende platformlandingsalgoritme vir 'n onbemande outonome helikopter suksesvol ontwerp en 'n aantal stelsels ontwikkel om die landingsalgoritme te implementeer.
Deur 'n kombinasie van 'n MCA-gebaseerde skipbewegingvoorspellingsalgoritme en die toepaslike ontleding van platformbewegingkriteria, is 'n stelsel ontwikkel wat geldige landingsgeleenthede in realeskipbewegingsdata kan identifiseer. Vir skipbewegingsdata wat by seetoestand 4 opgeneem is kan landingsgeleenthede 5 s in die toekoms met ‘n 75% sekerheid identifiseer word.
Die bandwydte van die afgeebewegingafskatter en beheerder van die helikopter is deur die implementering van GPS vertragingkompensasie, en snelheid en versnelling vorentoe-voer terme onderskeidelik verhoog. Die gevolglike bandwydte van minstens 0.2 Hz is voldoende om die afgeebeweging van 'n platform te volg wat die beweging van 'n skip by seetoestand 4 of laer simuleer.
Nadat die stelsels geïntegreer is is hulle gekoördineer in 'n landingtoestandsmasjien. 'n Stilstaande platform landing is suksesvol gedemonstreer tydens vlugtoetse, wat die funksionaliteit van die landingtoestandsmasjien en die integrasie van die stelsel bewys. Landings op 'n platform wat die beweging van 'n skip by seetoestand 4 simuleer is suksesvol in hardeware-in-die-lus simulasies gedemonstreer.
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:sun/oai:scholar.sun.ac.za:10019.1/96780 |
| Date | 03 1900 |
| Creators | Bellstedt, Philip |
| Contributors | Jones, Thomas, Stellenbosch University. Faculty of Engineering. Dept. of Electrical and Electronic Engineering. |
| Publisher | Stellenbosch : Stellenbosch University |
| Source Sets | South African National ETD Portal |
| Language | en_ZA |
| Detected Language | English |
| Type | Thesis |
| Format | 237 pages : illustrations |
| Rights | Stellenbosch University |
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