Hybrid Sensor-Based Backstepping Control Approach with Its Application to Fault-Tolerant Flight Control

Recently, an incremental-type sensor-based backstepping control approach, based on singular perturbation theory and Tikhonov’s theorem, has been proposed. This Lyapunov-function-based method uses measurements of control variables and less model knowledge, and it is not susceptible to the model uncertainty caused by fault scenarios. In this paper, the sensor-based backstepping method has been implemented on a fixed-wing aircraft with its focus on handling structural changes caused by damages. A new hybrid autopilot flight controller has been developed for a Boeing 747-200 aircraft after combining nonlinear dynamic inversion with the sensor-based backstepping control approach. Two benchmarks for fault-tolerant flight control, named rudder runaway and engine separation, are employed to evaluate the proposed method. The simulation results show that the proposed control approach leads to a zero tracking-error performance in nominal condition and guarantees the stability of the closed-loop system under failures as long as the reference commands are located in the safe flight envelope.