Stochastic precision analysis of hypersonic flight vehicle attitude control system in the presence of uncertainties

This study presents a novel stochastic precision analysis method for hypersonic flight vehicle (HFV) attitude control system in the presence of uncertainties, including parameter perturbation and external disturbance. Firstly, the HFV nonlinear attitude model considering parameter perturbation and external disturbance is established, and then a nonlinear attitude controller based on sliding mode variable structure control (SMVSC) is given. Secondly, the parameter perturbation is transformed into the equivalent external disturbance by the improved statistical linearization proposed. An improved Covariance Analysis Describing Equation Technique (CADET) is proposed for studying the stochastic precision. Thirdly, the improved stochastic precision analysis method is applied to HFV, and the attitude control system stochastic precision is analysed in the presence of uncertainties. Finally, the effectiveness of the improved HFV stochastic precision analysis method is verified by numerical simulations, as well as the Monte Carlo simulations. And then the influence of uncertainties on the stochastic precision of HFV attitude control system is analysed through multiple simulations. It is observed that the stochastic precision analysis method proposed performs better than traditional CADET, especially for HFV attitude system in the presence of parameter perturbation and external disturbance.