Design of attitude decoupling control system for BTT missile using quantitative feedback theory

Considering both the parameter uncertainty of mathematical model of BTT(bank-to-turn) missile and the strong coupling influence of three channels, a INA (inverse nyquist array)-based method to design precompensation matrix for approximately decoupling is proposed in combination with a method to design the controller by using QFT (quantitative feedback theory). Firstly, a precompensation is designed for the mutual coupling three channels, and the inverse transfer function matrix of open-loop forward-channel is converted into the diagonal dominance according to the changes in the way that Gershgorin circle surrounds the origin. Secondly, according to the parameter variation range of the multiple models of a certain missile´s three channels, a robust controller is designed by using QFT. Finally, a nonlinear simulation is carried out on a certain type of BTT missile to test its six degree-of-freedom (6DOF). The result shows that this robust control method maintains a high stability even in cases of parameter uncertainty, and succeeds in realizing three-channel´s approximate decoupling, which enables angle of attack α, sideslip angle ß and roll angle γ to track the anticipant instruction. Therefore, it is effective and feasible with promising engineering applicability.