F-16 flight control system design by using continuous time generalized predictive control

Autopilot and flight control systems have an extremely important place in todays's aviation and defense technologies. To be able to accomplish long and successful missions with aircrafts, decreasing or even eliminating the human workload is one of the major research areas of aerospace industry and many R&D studies are available about flight control systems for this purpose. These studies are rlying on different control methods and high performance military aircrafts are just one of the application areas. Primary goal of this thesis is to contribute to the autopilot and flight control systems of the 5^th generation fighter aircraft which will be the outcome of newly started and ongoing Turkish Fighter aircraft project (TF-X). For this purpose, as a high performance military aircraft, F-16 is chosen to design a flight control system. The main reasons for choosing F-16 as the aircraft model in this thesis are its being in use in Turkish Air Forces and being in production in Turkey. Also, there are many resources available about F-16. Firstly, a nonlinear model of F-16 is built with using high fidelity aerodynamic database then trim conditions and linear model are obtained from the nonlinear model. After obtaining the linear model, a comparison and validation is done with the nonlinear model and both pilot suported and semi-autonomous flight control system are designed with using this linear model. Continuous time Generalized Predictive Control (CGPC) method is used as a control law. CGPC is a powerful control method which is based on prediction of the system output. The reason for choosing the CGPC method is that it is a high performance controller and easy to choose the controller paramaters to obtain a desired performance. All the flight controller designs are done with regard to criteria's about the flight quality, handling quality and military standards and a detailed analysis is perfomed with this respect. In order to reduce the pilot workload and also have successful missions, satisfying the handling criterias while designing flight controller is so important, especially for the manned aircraft. Moreover, controller designs must be done to stay out of the PIO phenomenon which defines the mismatch between the pilot and the flight control system. So, flight control systems to support the pilot are designed with regard to these criterias. With the designed controllers, aircraft lateral-directional and longitudinal stability are achieved and each controller tracking performance are analyzed for both time and frequency domains. To be able to make more realistic simulations, sensor models, actuator models and extra time delays associated with software and hardware, are added into the nonlinear model.