QFT compound controller design method for improving workspace motion fidelity of hydraulic flight simulators

A novel quantitative feedback theory (QFT) compound controller design method is presented for improving the whole workspace fidelity of hydraulic flight simulators. The method acquires system models at different operating points of whole workspace through indirect closed-loop identification with power spectrum estimation. Then in controller designing, it designs forward controller and pre-filter with QFT to satisfy indices of magnitude frequency characteristics. Indices of phase frequency characteristics are fulfilled with feed-forward controller that is a tradeoff between the maximum and minimum bounds of magnitude and phase. Simulation results indicate that controllers designed with the proposed method could achieve performance specification requirements over whole workspace.