Helicopter mathematical modelling and optimal controller design

In this bachelor thesis, a nonlinear mathematical model simulation and linear controller design for the U1-H1 helicopter was achieved. This thesis is divided into two parts. In the first part, the nonlinear dynamic model is developed using the Matrix Laboratory Software and Heli-Dyn R Software, which is a modeling and simulation tool for rotorcraft developed by Dr. Ilkay Yavrucuk at Middle East Technical University. The non-linear model consists in a contribution of main rotor, tail rotor, fuselage, gravitational model, horizontal and vertical tail rotor. The U1-H1 main rotor non-linear mathematical model was build by use of blade element momentum theory, inflow dynamics and flapping dynamics. The total forces and moments are used in 6 degrees of freedom equations of motion model and helicopter states are obtained for hover conditions and forward flight. Trim and linearization process was done by Heli-Dyn R Software. The second part consists in a stability augmentation systems (SAS) followed by a set of automatic flight control systems (AFCS) designed by use of PID controllers. The AFCS main objective is to ease the pilot by decreasing the workload. The stability augmentation systems was designed by use of optimal control, especially Linear Quadratic Tracking Controller (LQT) and Linear Quadratic Regulator Controller (LQR). The automatic flight control systems implemented are heading hold, attitude, hold altitude acquire and hold mode for hover condition and heading hold, attitude hold, altitude acquire and hold mode and airspeed hold for forward flight condition. Furthermore, in order to check the robustness of the controllers and directory modes, disturbances were added to the model. The nonlinear model in trim mode simulations shown that the U1-H1 has achieved hovering conditions and forward flight successfully. Furthermore, the controllers and directory modes shown a successful dynamic behavior towards perturbations