Longitudinal automatic carrier landing system guidance law using model predictive control with an additional landing risk term

Abstract

This paper used a model predictive control with an additional term to develop a modified longitudinal guidance law to reduce landing risk in an automatic carrier landing system. The landing risk model was established by using a longitudinal trajectory and touchdown point predictive principle. A traditional MPC was then involved in designing a modified automatic carrier landing system guidance law for the proposed model. The nonlinear landing mathematic model of an F/A-18 carrier-based aircraft was initially established. Considering the processed procedure in the model predictive control algorithm, the corresponding linear landing model was derived on the basis of the equilibrium states of the F/A-18. Second, landing trajectory in the longitudinal plane was analysed so that the predictive principle of the trajectory trend was reasonably addressed. Depending on the experimental sample data of a pilot model, some linear imitating envelopes are transformed from the corresponding nonlinear trajectory clusters. Furthermore, a touchdown point prediction model was further established based on the predicted trajectory and touchdown point. Third, the traditional model predictive control was introduced to integrate the landing risk term in the performance cost function to develop a novel modified algorithm that not only guides the aircraft to automatically approach and land on the carrier, but also eliminates landing risk during the final carrier approach. Linear matrix inequalities were imported to substitute algebraic inequalities derived from this new algorithm to increase calculating speed. A simulation mission was conducted on a semi-physical platform and compared with the traditional model predictive control without the additional term. The theoretical results validated the correctness and robustness of the modified algorithm and its capability to eliminate landing risk during terminal carrier approach.