Control of large flexible structures-an experiment on the NASA Mini-Mast facility

The output variance constraint controller design procedure is integrated with model reduction by modal cost analysis. A procedure is given for tuning MIMO controller designs to find the maximal RMS performance of the actual system. Controller designs based on a finite element model of the system are compared with controller designs based on an identified model (obtained using the Q-Markov cover algorithm). The identified model and the finite-element model led to similar closed-loop performance, when tested in the Mini-Mast facility at Langley Research Center, The linear controllers designed tolerated significant Coulomb friction in the joints of the structure, even though robustness with respect to parameter variations was not included in the design.<>