Abstract
This paper focuses on the attitude control and propellant slosh suppression of aeroelastic launch vehicles. Four candidate controllers are proposed: the Linear Quadratic Regulator (LQR), the Incremental Non-linear Dynamic Inversion (INDI) control, the Incremental Sliding Mode Control (INDI-SMC), and the Feedback Linearisation-based Sliding Mode Control (FL-SMC). Theoretical analyses show INDI itself is unable to deal with under-actuated systems. Therefore, when applied to the launch vehicle directly, it cannot simultaneously track the pitch command and effectively suppress the slosh dynamics. This issue is solved by INDI-SMC, which also has enhanced robustness against both matched and unmatched uncertainties. Furthermore, despite its reduced model dependency, INDI-SMC has better robustness against model uncertainties and external disturbances than FL-SMC. These merits of INDI-SMC are verified by various simulation results. First, when the nominal plant configuration is adopted, the system using INDI-SMC has the smallest pitch-angle tracking error. The slosh motion is also effectively damped out. Second, Monte-Carlo studies are used to test the robustness of LQR, INDI-SMC, and FL-SMC to parametric uncertainties. Among these three controllers, LQR shows the worst performance and largest control-effort outliers. On the contrary, both INDI-SMC and FL-SMC can resist a wider range of perturbations without significant performance degradation. Even so, the tracking and slosh damping performance of INDI-SMC is still the best. Finally, both INDI-SMC and FL-SMC show robustness against unmodeled dynamics, while the robust performance of INDI-SMC is superior.
Original language | English |
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Title of host publication | AIAA Scitech 2021 Forum |
Subtitle of host publication | 11–15 & 19–21 January 2021, Virtual Event |
Publisher | American Institute of Aeronautics and Astronautics Inc. (AIAA) |
Number of pages | 23 |
ISBN (Electronic) | 978-1-62410-609-5 |
DOIs | |
Publication status | Published - 2021 |
Event | AIAA Scitech 2021 Forum - Virtual/online event due to COVID-19 , Virtual, Online Duration: 11 Jan 2021 → 21 Jan 2021 |
Conference
Conference | AIAA Scitech 2021 Forum |
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City | Virtual, Online |
Period | 11/01/21 → 21/01/21 |