A New Joint Sensor Based Backstepping Control Approach for Fault-Tolerant Flight Control
Recently, an incremental type sensor based backstepping (SBB) control law, based on singular perturbation theory, was proposed. This Lyapunov function based method uses measurement data rather than the model knowledge, and has the advantage that the model uncertainty plays only a minor role. In this paper, the above mentioned SBB method has been extended to deal with fault tolerant flight control when failures occur to the aircraft. A new double-loop joint SBB attitude controller, as well as a hybrid nonlinear dynamic inversion (NDI)/SBB attitude controller, has been developed for a Boeing 747-200 aircraft. The benchmarks namely rudder runaway case and engine separation scenario are employed to evaluate the proposed methods. The simulation results show that the proposed joint SBB attitude control method can achieve a zero-error tracking performance in nominal condition and can guarantee the stability of the closed-loop system, under the aforementioned two failures, as long as the reference commands are achievable. Comparing with the hybrid NDI/SBB method, the joint SBB attitude control setup has an advantage in eliminating the tracking error of the sideslip angle without needing the onboard model information.