Backstepping control based on L₁ adaptive theory for large transport aircraft heavy load airdrop

Abstract

A study of the L 1 adaptive controller is conducted based on the backstepping method for the model of large transport aircraft with drastic changes appearing in heavy load airdrop process. The system is divided into an attitude subsystem and a velocity subsystem. For the attitude subsystem, the backstepping control is used to design the virtual control of path angle and the pitch angle in external loop with the L 1 adaptive controller designed in internal loop to estimate the uncertainties and disturbances in the subsystem and to compensate them. In the stability analysis, the uniform boundedness of all signals in the closed-loop system is proven. Simulation results show that the proposed control method preserves the quick dynamic torque response, high efficiency, and robustness in heavy load airdrop; to some extent it can alleviate the control switch lead or lag problem and ensure the safety of the transport aircraft to fulfill the complete airdrop mission.

Safety Assessment of Transport Aircraft Heavy Equipment Airdrop: An Improved STPA-BN Mechanism

“…Methods focused on the risks of human contributions to the stability domain of this human-machine-environment closedloop system were proposed to study problems during a heavy equipment airdrop such as pilots operating too violently or airdropper's inappropriate decision making [4,5]. Focusing on mechanical risks, control methods have been proposed to study aircraft-cargo coupling characteristics, equipment blocking failure, equipment sliding disturbance, equipment stability under drastic changes during heavy equipment airdrop, and constraints between the extraction parachute and the equipment [6][7][8][9][10]. Focusing on risks posed by the environment, methods have been developed to improve the anti-interference of aircraft to ensure the robustness of heavy equipment airdrop to guard against effects of lateral wind, disturbed wind, and atmospheric turbulence during a heavy equipment airdrop [11].…”