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Analysis, Simulation, and Measurement of Micro-Vibrations in Reaction Wheels for High-Performance Imaging Missions
Thesis (MEng)--Stellenbosch University, 2026.
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| Format: | Thesis |
| Language: | English |
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Stellenbosch : Stellenbosch University
2026
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| _version_ | 1867613983640387584 |
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| access_status_str | Open Access |
| author | Du Plessis, Maria Richardt |
| author2 | Steyn, W. H. |
| author_browse | Du Plessis, Maria Richardt Steyn, W. H. |
| author_facet | Steyn, W. H. Du Plessis, Maria Richardt |
| author_sort | Du Plessis, Maria Richardt |
| collection | Thesis |
| dc_rights_str_mv | Stellenbosch University |
| description | Thesis (MEng)--Stellenbosch University, 2026. |
| format | Thesis |
| id | oai:scholar.sun.ac.za:10019.1/135768 |
| institution | Stellenbosch University (South Africa) |
| language | English |
| last_indexed | 2026-06-10T12:44:49.127Z |
| license_str | Other — see source repository |
| provenance_str_mv | Harvested via OAI-PMH from SUNScholar — Stellenbosch University Repository |
| publishDate | 2026 |
| publishDateRange | 2026 |
| publishDateSort | 2026 |
| publisher | Stellenbosch : Stellenbosch University |
| publisherStr | Stellenbosch : Stellenbosch University |
| record_format | dspace |
| source_str | SUNScholar — Stellenbosch University Repository |
| spelling | oai:scholar.sun.ac.za:10019.1/135768 Analysis, Simulation, and Measurement of Micro-Vibrations in Reaction Wheels for High-Performance Imaging Missions Du Plessis, Maria Richardt Steyn, W. H. Jordaan, H. W. Stellenbosch University. Faculty of Engineering. Dept. of Electrical and Electronic Engineering. Thesis (MEng)--Stellenbosch University, 2026. Du Plessis, M. R. 2026. Analysis, Simulation, and Measurement of Micro-Vibrations in Reaction Wheels for High-Performance Imaging Missions. Unpublished masters thesis. Stellenbosch: Stellenbosch University [online]. Available: https://scholar.sun.ac.za/items/a1d24fd8-5007-437c-929d-cb592fe3b177 High-performance imaging satellite missions require exceptional pointing stability to ensure image quality and geometric fidelity. This stability is often degraded by micro-vibrations originating from reaction wheels, which are the primary attitude actuators. These vibrations, resulting from mechanical unbalance, torque ripple, and bearing imperfections, propagate through the satellite structure and induce line-of-sight (LoS) jitter. This thesis presents the analysis, simulation, and measurement of reaction wheel micro-vibrations to characterise their effect on LoS stability and to evaluate mitigation strategies aimed at improving overall pointing performance. A complete analytical model was developed to describe the disturbance forces and torques generated by a reaction wheel, including static and dynamic unbalance and structural resonances. The model was implemented in a Matlab Simulink simulation environment to predict the resulting LoS disturbances for a four-wheel pyramid configuration. Experimental measurements were performed using a six-axis Kistler force-torque sensor to quantify the disturbance spectra of single and pyramid reaction wheel assemblies. The results were used to validate the analytical and simulation models. Additional testing on a reaction wheel pyramid mounted to an elastomeric isolation system quantified the attenuation of transmitted vibrations and demonstrated the effectiveness of passive isolation at high frequencies, as well as its limitations at low frequencies. Finally, an air-bearing platform experiment was used to relate the measured disturbances to spacecraft-level pointing errors. The combined modelling, simulation, and experimental framework provides a validated method for predicting reaction-wheel induced micro-vibrations and assessing their impact on LoS stability. The results confirm that unbalance-related disturbances are the dominant contributor to LoS instability in small, high-resolution imaging satellites and demonstrate how the developed framework can be used to evaluate and optimise isolation techniques and balancing strategies for future missions. Masters 2026-04-10T05:57:51Z 2026-04-10T05:57:51Z 2026-03 Thesis https://scholar.sun.ac.za/handle/10019.1/135768 en Stellenbosch University 118 pages : ill. application/pdf Stellenbosch : Stellenbosch University |
| spellingShingle | Du Plessis, Maria Richardt Analysis, Simulation, and Measurement of Micro-Vibrations in Reaction Wheels for High-Performance Imaging Missions |
| title | Analysis, Simulation, and Measurement of Micro-Vibrations in Reaction Wheels for High-Performance Imaging Missions |
| title_full | Analysis, Simulation, and Measurement of Micro-Vibrations in Reaction Wheels for High-Performance Imaging Missions |
| title_fullStr | Analysis, Simulation, and Measurement of Micro-Vibrations in Reaction Wheels for High-Performance Imaging Missions |
| title_full_unstemmed | Analysis, Simulation, and Measurement of Micro-Vibrations in Reaction Wheels for High-Performance Imaging Missions |
| title_short | Analysis, Simulation, and Measurement of Micro-Vibrations in Reaction Wheels for High-Performance Imaging Missions |
| title_sort | analysis simulation and measurement of micro vibrations in reaction wheels for high performance imaging missions |
| url | https://scholar.sun.ac.za/handle/10019.1/135768 |
| work_keys_str_mv | AT duplessismariarichardt analysissimulationandmeasurementofmicrovibrationsinreactionwheelsforhighperformanceimagingmissions |