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Finite element model-based robust controllers for the middeck active control experiment (MACE)

The middeck active control experiment (MACE) is a space shuttle flight experiment intended to demonstrate high authority active structural control in zero gravity (0-g) conditions based on analysis and ground testing. Finite element structural models are very important for the MACE program because they can be used to predict the on-orbit dynamics of the test article. However, finite element models tend to be inaccurate, requiring the use of parametric robust control techniques to achieve good performance. Several such control techniques and an overall design methodology are discussed in this paper. Experimental results from several tests are used to illustrate the feasibility of achieving good H/sub 2/ performance on the test article with robust controllers based on the finite element model. This demonstration improves confidence in the eventual on-orbit performance of this experiment and other future spacecraft.