Derivation of zero-gravity structural control models from analysis and ground experimentation

The Middeck Active Control Experiment (MACE) is a Space Shuttle flight experiment that flew on STS-67 in March 1995, to demonstrate high-authority active structural control in microgravity conditions. Because no experimental on-orbit data were available before flight, the model used to derive these controllers was obtained from a combination of analysis and openand closed-loop ground testing. A modeling approach to obtain this 0-g model is presented along with its application to the MACE test article. This approach starts with a 1-g model, which includes gravity and suspension effects. This 1-g model is improved using ground test results in a process called updating. Once updated, it is verified through a combination of structural perturbation and closed-loop control. Finally, the gravity and suspension effects are removed to arrive at a prediction of the 0-g behavior of the structure. Flight data are used to demonstrate the effectiveness of this approach.