Fault-Tolerant Flight Control Based on Two-Stage Approach and Interior Point Method

In the field of flight control, it is an important issue to assure the flight performance even if some actuators fail. In the viewpoint of mathematics, aircraft dynamics can be described as an input affine system, so a two-stage control approach for the affine system is adopted here. At the first stage, to generate virtual inputs related to the intended maneuver, nonlinear inverse control technique is adopted. At the second stage, an actuator reassignment problem how to achieve necessary virtual inputs by remaining available actuators is considered. Taking into account the physical limits of the remaining actuators as well as those of the aircraft structure, this problem is organized as a quadratic programming problem solved on-line to generate reference signals for remaining available actuators. The proposed solution method for this formulated programming problem is based on an interior point method. Numerical simulation results based on a nonlinear aircraft model show that the proposed approach can provide an acceptable flight performance with some actuators failure.