A Study on Aircraft Pitch Control in Rejecting Disturbances

An introductory study on simplified aircraft pitch control considering the different variants of the well-known proportional-integral-derivative (PID) controller is presented in this paper. Different control methods have been applied in the aircraft systems control. The linear control methods are not suitable due to highly nonlinear nature of the plant. The intelligent methods lack comprehensive models hampering more rigor research. The nonlinear require higher computing time making their real implementation impossible. The model of the aircraft is a simplified analytical model derived using one of Boeing aircraft models. Investigated are the performances of the PID, PI, and PD controllers. A pulse disturbance was considered to mimic wind, gust, or sudden torque change. Sensor error was considered in the evaluation. The work was achieved by simulation using MATLAB/SIMULINK software. Results showed that PID and PD controllers have similar results while the PI controller has oscillations. Further results show that both the PID and PD are able to suppress the disturbance whose value can result in deviation equals to the reference pitch angle that is; 11° to about 22°. The two controllers however show very poor performance in rejecting sensor errors that is; from 2.2° to just 2°. The PD controller can serve same purpose as the PID controller in aircraft pitch control. Consequently, the study would help to serve as basis for research in aircraft pitch control for beginning as well as new comers and naïve in the area of flight control.