Nonlinear Comprehensive Decoupling Controller Based on Direct Lift Control for Carrier Landing

Abstract

In this study, the direct lift control (DLC) method was introduced into the carrier landing control law. Characterized by quick response and high accuracy, the DCL method can help us overcome the “backhoe” character, reduce the pilot’s control burden, and improve the accuracy and safety of carrier landing. A two-level integrated landing controller was designed by combining the prescribed performance nonlinear dynamic inversion and control allocation algorithm. The decoupling between longitudinal trajectory and attitude controls, as well as the decoupling between horizontal control and longitudinal motion, was considered. First, a six-degree-of-freedom nonlinear model of an aircraft was established. Second, a dynamic inverse loop was organically connected with the control allocation loop by setting the intermediate virtual control vector. And the control performance of the dynamic inverse control loop was improved by prescribing the error vector constraint equation. Finally, the simulation results showed that the designed direct lift controller can correct the vertical path while keeping the angle of attack and flight speed stable and prevent the aircraft from losing altitude when aligning with the center line. Overall, the designed direct lift control system can improve trajectory control efficiency in carrier landing and reduce pilots’ burden.