Optimal generalized predictive control for a near-space vehicle based on nonlinear disturbance observer

An optimal generalized predictive control (GPC) law is developed for a near-space hypersonic vehicle in reentry flight. The nonlinear disturbance observer (NDO) technique is combined with the control law for the output to track the reference attitude angles and angular velocities in the presence of uncertainties and disturbances. The prediction defined on finite horizon is carried out via Taylor series expansion. The unmodeled dynamics and unknown disturbances are estimated by the nonlinear observer. The optimal GPC controller of the vehicle with the NDO turns out to be able to attain the optimal index in mathematics. The stability proof of the NDO is also provided in the paper. The simulation results show satisfactory performance of the given controller for reentry attitude control, and the robustness to parameters variations and the disturbance rejection are successfully accomplished.