Larger power requirements from modern spacecraft precipitate enormous solar arrays to fulfil budgetary needs. Although the solar arrays may have a relatively small influence on the total mass of the spacecraft system, large arrays with long flexible panels do affect the dynamics of the satellite bus through the Steiner terms in the moments of inertia. Unfortunately, such large arrays are broad targets for incoming orbital debris, and impacts are an increasing risk to attitude control and during guidance operations. This paper examines the effect of impacts on the response of a Rosetta-like spacecraft controlled by an adaptive controller. The control system design is based on simple adaptive control theory, and uses a stabilised, linear reference model to swiftly drive the plant output error to zero and hence achieving a commanded attitude. The adaptive controller is tuned using a linearised Euler-Bernoulli beam model as a computationally inexpensive flexible system. The elastic dynamics increases the controller effort and shows the effect of the elastic bodies on the controller system by the deviations from an implementation for a rigid satellite only. A sample investigation of an impulsive force, simulating a particle debris impact, shows the control effort exerted to stabilise the spacecraft. Additional simulations covering a range of particle momenta and impact location on the spacecraft show controller efforts for a satellite in a steady-state configuration and undergoing a three-axis manoeuvre. For individual impact cases, the controller shows a robust performance, even if there is some initial saturation of the actuators. In multiple impact scenarios, the control effort is much heavier and strong oscillatory behaviour is observed, indicating the limits of the controller.
展开▼
