On robust LPV-based observation of fuel slosh dynamics for attitude control design

Abstract

Most attitude control scenarios are highly affected by fuel slosh dynamics that must be carefully taken into account to preserve pointing accuracy. Since such dynamics are not easily predictable, standard strategies consist of bounding the performances of the control system to avoid interactions between the rigid dynamics of the spacecraft and the oscillating liquid motion inside the fuel tank. Thanks to a recently developed control-oriented CFD-based fuel slosh model, an alternative approach is evaluated in this paper. It is based on a reformulation of the slosh effects in the Linear-Parameter-Varying (LPV) framework from which a robust LPV observer is easily derived. The latter is then classically used in a disturbance compensation scheme. The proposed strategy is illustrated on a simple but realistic single axis attitude control scenario for a small satellite using reaction wheels.