Robust controller design for hypersonic vehicle based on QFT

For the problem of attitude control during the attitude regulation phase, the influence of different working conditions of scramjet on the parameters of the hypersonic vehicle model was treated as an extension of the model uncertainty robustness problem. A robust longitudinal flight controller based on QFT was designed. To make the closed loop transfer function meet all the desired performance requirements, the composite bounds on the Nichols chart were generated with the frequency domain specifications converted from desired time domain specifications of flight control system and the design of the controller and pre-filter was performed by loop shaping. Simulation results show that the designed controller satisfies the performance specifications, rejects output disturbance effectively and is robust when the uncertain model parameters vary within large range. The proposed controller can be applied in engineering with favorable robust property.