Three-channel Decoupling Control for Fighter Aircraft based on Prescribed Performance Control and Super-Twisting Extended State Observer

In this paper, we propose a three-channel decoupling control method for fighter aircraft based on prescribed performance control (PPC) and super-twisting extended state observer (STESO) to solve the problem of high uncertainty and strong coupling during flight at high angle of attack. In this method, the angle of attack, the sideslip angle and bank angle around the velocity are selected as the controlled variables respectively, and three independent controllers are designed to control these variables separately, which reduces the coupling of the system and improves the control effect by decoupling the control. By taking advantage of the linear extended state observer(LESO) and the super-twisting algorithm, a STESO is used to estimate the total disturbance(including coupling terms between individual channels, modeled uncertainty, external disturbance, etc.) and compensate for them in the control law. Moreover, the control performance and robustness of STESO are verified by simulation analysis. Simulation results show that the proposed STESO achieves rapid convergence of the tracking error with less settling time compared to LESO. The controller employing the proposed observer is capable of promptly and accurately tracking control commands.