Composite nonlinear predictive control based on finite-time disturbance observer for Mars entry vehicle

A new composite nonlinear predictive control (NPC) method based on finite-time disturbance observer is proposed for Mars entry drag trajectory tracking. The composite controller uses nonlinear predictive control strategy in a feedback regulation way to obtain desired tracking performance and uses the disturbance estimation based on finite-time disturbance observer (FTDO) to compensate uncertainty in a feedforward way. The proposed guidance law not only compensates the matched disturbance but also the mismatched disturbance. The drag tracking error is also guaranteed to converge to 0 even when the disturbance is time-varying and related with states.