Adaptive fault-tolerant boundary control for a flexible aircraft wing with input constraints

This paper discusses the boundary control problem of actuator input constraints for a flexible aircraft wing in the presence of unknown external disturbances and unknown actuator failure. Based on the application of smooth hyperbolic function and a projection algorithm, an innovative adaptive boundary controller with an external disturbance estimator is designed to suppress the bending and twist deformations of the flexible aircraft wing. The flexible aircraft wing is modeled as a coupled twist-bending system, the dynamics of which are described by several partial differential equations (PDEs) and ordinary differential equations (ODEs). The proposed boundary control scheme is shown to satisfy the input restrictions and physical conditions. The elastic vibration and vibration rate of the flexible aircraft wing system is also eliminated successfully even after the actuator failure. Both theoretical analysis and numerical simulations are provided which demonstrate the effectiveness of the proposed scheme.