Modeling and parameter estimation of spacecraft fuel slosh mode

The nutation (wobble) of a spinning spacecraft in the presence of energy dissipation is a well-known problem in dynamics and is of particular concern for space missions. Its rate of growth is characterized by the nutation time constant (NTC). For analytical prediction of the NTC this fuel slosh is often modeled using simple mechanical analogs such as pendulums or rigid rotors coupled to the spacecraft. Identifying model parameter values which adequately represent the sloshing dynamics is the most important step in obtaining an accurate NTC estimate. Currently, the identification of the model parameters is a laborious trial-and-error process in which the equations of motion for the mechanical analog are hand-derived, evaluated, and their results are compared with the experimental results. The current research is an effort to automate the process of identifying the parameters of the slosh model using a Matlab/SimMechanics based computer simulation of the experimental setup