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Analytical landing trajectories for embedded autonomy

Li, Maodeng and Macdonald, M. and McInnes, C.R. and Jing, Wuxing (2010) Analytical landing trajectories for embedded autonomy. Proceedings of the Institution of Mechanical Engineers, Part G: Journal of Aerospace Engineering, 224 (11). pp. 1177-1191. ISSN 0954-4100

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    Abstract

    This paper considers an optimal guidance law for the initial braking phase of a soft landing mission on a celestial body without atmosphere in which boundary conditions on height and velocity are specifed. The optimal lander attitude for the minimum fuel landing problem is found. An analytic optimal trajectory is achieved by expanding the thrust acceleration, gravitational acceleration and the cosine of the vertical attitude angle to a high-order polynomial. Coefficients of these polynomials are obtained from the boundary conditions. A fixed gain control law and a direct adaptive control law are then developed to track the analytical reference trajectory. Finally, a mission scenario is presented to illustrate the accuracy of the analytical trajectory and validity of the control laws developed. The use of direct adaptive control for embedded autonomy will be directly contrasted against a traditional fixed gain controller, using a Lunar landing scenario. The advantage of the direct adaptive control approach is that it does not require system monitoring to detect thruster failure and can adjust its gain automatically. As such, direct adaptive control combined with the developed analytical solution enables autonomy to be embedded within the lander guidance and control system. In addition, it is shown that direct adaptive control increases the probability of lander survival through faster transient response and stability than a traditional fixed gain controller with system level failure detection and recovery.

    Item type: Article
    ID code: 18411
    Keywords: analytical landing trajectories, optimal lander attitude, high-order polynomial, mission scenario, lander guidance, control system, Mechanical engineering and machinery, Motor vehicles. Aeronautics. Astronautics, Mechanical Engineering, Aerospace Engineering
    Subjects: Technology > Mechanical engineering and machinery
    Technology > Motor vehicles. Aeronautics. Astronautics
    Department: Faculty of Engineering > Mechanical and Aerospace Engineering
    Related URLs:
    Depositing user: Ms Katrina May
    Date Deposited: 25 Mar 2010 09:48
    Last modified: 05 Sep 2014 13:42
    URI: http://strathprints.strath.ac.uk/id/eprint/18411

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