A case study on spacecraft attitude control

Rihan Ahmed, Da-Wei Gu, Ian Postlethwaite

    Research output: Chapter in Book/Report/Conference proceedingChapterpeer-review

    11 Citations (Scopus)


    In this paper, we present a case study on spacecraft attitude control. The plant (spacecraft attitude model) is a second order, nonlinear, multi-input-multi-output system defined by Euler's equations of rotational motion and the kinematic differential equations. The modified Rodrigues parameter (MRP) is used for kinematic parametrization and is the only measurable variable at the plant output. It is shown that the non-linear plant can be globally asymptotically stabilized by an output feedback control law proposed in the paper. Stability is proved by Lyapunov's theorem with a new Lyapunov candidate function. In the control scheme design method, the rate of change of the output (attitude) is approximated using a high gain, high pass filter located in the inner feedback loop. In this way, the proposed control scheme possesses the robustness and simplicity of a PD controller, but does not require attitude rate measurement, angular velocity measurement or direct use of differentiators. Furthermore, the control scheme does not require any information about the body principal moments of inertia and is therefore robust with respect to system parametric uncertainty. This makes the approach practically useful and acceptable by practising engineers. The simulations included in the paper show the robust performance and zero tracking error of the overall closed loop, demonstrating the effectiveness of the proposed stabilization approach. Finally, the paper includes a comparison between the controllers designed by the proposed scheme, by an H¿ loop shaping design procedure and by a mixed sensitivity design, for the same given plant.
    Original languageEnglish
    Title of host publicationProceedings of the 48h IEEE Conference on Decision and Control (CDC) held jointly with 2009 28th Chinese Control Conference
    Place of PublicationPiscataway, NJ
    ISBN (Print)978-1424438716
    Publication statusPublished - 29 Jan 2009
    Event48th IEEE Conference on Decision and Control - Shanghai, China
    Duration: 29 Jan 2009 → …


    Conference48th IEEE Conference on Decision and Control
    Period29/01/09 → …


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