Adaptive Differential Thrust Methodology for Lateral/Directional Stability of an Aircraft with a Completely Damaged Vertical Stabilizer

摘要

This paper investigates the utilization of differential thrust to help acommercial aircraft with a damaged vertical stabilizer regain itslateral/directional stability. In the event of an aircraft losing its verticalstabilizer, the consequential loss of the lateral/directional stability andcontrol is likely to cause a fatal crash. In this paper, an aircraft with acompletely damaged vertical stabilizer is investigated, and a uniquedifferential thrust based adaptive control approach is proposed to achieve astable flight envelope. The propulsion dynamics of the aircraft is modeled as asystem of differential equations with engine time constant and time delay termsto study the engine response time with respect to a differential thrust input.The proposed differential thrust control module is then presented to map therudder input to differential thrust input. Model reference adaptive controlbased on the Lyapunov stability approach is implemented to test the ability ofthe damaged aircraft to track the model aircraft's (reference) response in anextreme scenario. Investigation results demonstrate successful application ofsuch differential thrust approach to regain lateral/directional stability of adamaged aircraft with no vertical stabilizer. Finally, the conducted robustnessand uncertainty analysis results conclude that the stability and performance ofthe damaged aircraft remain within desirable limits, and demonstrate a safeflight mission through the proposed adaptive control methodology.