Development of Structural Uncertainty Models

The development and utilization of an uncertainty model for structures that undergo a change in operational environment is presented. Themotivatingapplicationis the developmentof an on-orbit (0-g) uncertaintymodel for structural control based solely on ground (1-g) modeling and experimentation, although other applications can be used. A parametric uncertainty model (mean errors and bounds on modal parameters) is developed for a nominal environment and then localized to speciŽ c degrees of freedom (mass and stiffness uncertainties) using a Ž rst-order sensitivity method. The nominal mass and stiffness uncertainties are then projected into a modiŽ ed environment to create an analogous,modiŽ ed uncertainty model. Themiddeck active control experiment is introduced to verify the prediction of a space-based uncertainty model.