Integrated guidance and control design considering system uncertainty

The hypersonic vehicle has the characteristics of strong coupling, high uncertainty and complex nonlinearity, leading to an unsatisfactory control performance with the traditional design method. In this paper, an integrated guidance and control design approach is proposed to cope with this problem. A time-varying longitudinal integrated guidance and control model is first formulated, and then the overall uncertainty consisting of the un-modeled dynamic, parameter uncertainty and external disturbance is taken into account. A novel finite-time extended state observer is developed to estimate and compensate it in real time. Furthermore, an integrated guidance and control algorithm utilizing back-stepping method and the dynamic inverse is put forward. It has been theoretically proved that the finite-time extended state observer system and the cascade system are globally finite-time stable. Numerical simulation results under different kinds of uncertainty with different amplitude and frequency are presented to illustrate the effectiveness and feasibility of the proposed approach. The proposed integrated guidance and control possesses a better convergence performance and stronger disturbance rejection property in existence of the mismatched uncertainty and parameter uncertainty.