Integrated Design of Flight Control System and Auxiliary Signal of Active Fault Detection Using a Multi-Model Approach

A flight control system (FCS) as an example of nonlinear systems should be stabilizing the airplane in healthy and faulty modes with the desired performance. In this paper, first, the nonlinear model of the flight system (FS) is linearized in predefined operating points, and the airplane’s healthy and faulty modes convert to a multi-model system. To eliminate the undesired effect of multi-modeling and the controller robustness that usually causes to mask the faults in FSs, the problem of integrated design of FCS based on active fault detection (AFD) is formulated. The proposed problem concluded to design the optimal auxiliary signal of AFD and a static, fixed, and full-order controller with the capability in reduced-order design. The FCS guarantees to stabilize all of the healthy and faulty models and to satisfy the performance constraints. In the following, to solve the formulated problem, a numerical solution based on the genetic algorithm is proposed. To evaluate the proposed method, two full-order and reduced-ordered controllers are designed for an aircraft in the case of actuator degradation conditions. The simulation results show the ability of the proposed method to meet the control objectives and design the auxiliary signal for AFD.