BTT autopilot design for agile missiles with aerodynamic uncertainty

The approach to the synthesis of autopilot with aerodynamic uncertainty is investigated in order to achieve large maneuverability of agile missiles. The dynamics of the agile missile with reaction-jet control system(RCS) are presented. Subsequently,the cascade control scheme based on the bank-to-turn(BTT)steering technique is described. To address the aerodynamic uncertainties encountered by the control system, the active disturbance rejection control(ADRC) method is introduced in the autopilot design. Furthermore, a compound controller, using extended state observer(ESO) to online estimate system uncertainties and calculate derivative of command signals, is designed based on dynamic surface control(DSC). Nonlinear simulation results show the feasibility of the proposed approach and validate the robustness of the controller with severe unmodeled dynamics.