Uav Flight Control System Control Laws Reconstruction Technology

Reconfigurable flight control system(RFCS) can tune the control distribution of the system with failure automatically according to the failure mode specified offline. It takes the advantage of control surfaces redundancy, which can ensure the stable flight or safe landing of the UAV. Therefore RFCS is very important for the flight safety and survivability of the aircraft and studied widely all over the world.The thesis mainly includes the following parts:1. The study background and significance of the thesis and RFCS are discussed, and the methods of the control law reconfiguration are classified. The development and the technical problems of the RFCS are introduced.2. The nonlinear and linear models are built according to the structure and the aerodynamic coefficients. The longitudinal and lateral control laws on specified state are designed using PID. It is the basic of the control law reconfiguration.3. Re-configurable ability under failure for linear system is presented. The control surfaces are separated according to the characteristics of the figure and aerodynamic coefficients, then the UAV is controlled by the independent control surfaces. The ability of control redundancy of the control surfaces is improved. The projects of control law reconfiguration with failure and lock of elevator and rudder are studied.4. The reconfiguration is implemented using model following method. The basic principle of the method is introduced firstly, then the reconfiguration model based on the method is designed. The longitudinal and lateral digital simulations of the model are implemented using Matlab. The results show the precision of the system following the reference model is good.5. Another reconfiguration method-pseudo-inverse method is introduced. The principle and feasibility of pseudo-inverse method are discussed. Control mixers for several typical failures based on this method are designed and simulated. At last, the parameter deflection test is made with the designed control mixers to evaluate robustness of reconfigured UAV with specific failures. The results show control mixers are beneficial to engineering application.