Longitudinal dynamics control of UAV

This paper presents comparative study between modern and classical controllers for pitch control of an aircraft system. The nonlinear differential equations of longitudinal motion of a rigid plane are developed from Newton's second law of motion. Linearization of these equations are accomplished using small disturbance theory. Stability derivatives for an Unmanned Aerial Vehicle (UAV) are chosen and its state space matrices are formed. Further a suitable longitudinal control based on four controllers namely, PID, LQR, LQG and Sliding mode controllers are designed, simulated and compared. A Kalman filter is designed and the system under disturbances is tested with designed PID controller and the filter. Simulations show that sliding mode controller is the best controller and exhibits stronger robustness properties to conquer system uncertainties. The results also reveals the effectiveness of the Kalman filer.