During the ascent phase of a missile, a challenging problem occurs that blocks the construction of a high-precision attitude control scheme, which directly affects accurate modeling including disturbances: non-linearities of an actuator, rapidly time-varying parameters, un-modeled dynamics, etc. In order to improve the control performance, an active disturbance rejection control (ADRC) scheme, considering non-linear dynamics of the actuator and wind disturbance during the ascent phase, is proposed in this paper. An expand state observer (ESO) is planned to estimate and compensate the actuator’s non-linear dynamics, flight model uncertainties, and wind disturbance. Therefore, the complex non-linear time-varying control problem is simplified into a linear time-invariant control problem. The pitch attitude control system is controlled by the cascade method and ADRC controllers are designed for actuator close loop and attitude control loop, respectively. The simulation results show that ADRC has strong robustness under different dead-zones and external disturbances of the actuator. On the other hand, ADRC can effectively suppress the external atmospheric disturbance. Compared with the traditional gain-scheduling control scheme, the ADRC scheme can significantly reduce the overloading of the system and shows remarkable performance for tracking as well as wind resistance.

The control of aeroelastic response of a wing section with influence of the fuel sloshing in external tank is examined through analytical studies. Based on the simplified mass-spring-damper equivalent mechanical model of the liquid sloshing and the dynamic modeling method of the wing/store system, the aeroelastic model of the two-dimensional wing/external tank/fuel sloshing system is established in this paper. The aeroelastic instability of the system is studied, and a flutter suppression controller is designed based on linear active disturbance rejection control (LADRC). The stability analysis shows that the tracking error and the estimation error of the linear state observer (ESO) are convergent. It is shown through simulation results that wing flutter suppression under the interference of fuel sloshing and external tank vibrating can be achieved by using two control surfaces.