The Control Method Study Of 3-DOF Twin Rotor Helicopter Model

Because of the static instability of helicopter, its flight control system is nonlinear,multivariable and strong coupling. Moreover, aerodynamic characteristics of helicopter rotor are very complex and there are also many non-determining factors in the actual flight.Therefore, it is necessary to make the flight controller be strong robust to the unknown uncertainties and external disturbances, in order to ensure the flight stability and security of the helicopter.As the helicopter flight test has high risk and sensors cost, there are many security risks in the actual flight to prove control algorithms. 3-DOF helicopter model is used as the object in this study; LQR based on decomposition and H∞ control method based on the mixed sensitivity are adopted to do some researches of helicopter control laws.1 、 The linear uncertainty model of the object is established. The bounded uncertainty parameters are transformed into uncertainty of parameters; added with inherent parameters perturbation, it composes systems’ linear uncertainty model.2、The 3-DOF helicopter model is divided into two subsystems by decomposition theory,PID control and LQR optimal control methods are adopted respectively to design controllers of the aircraft model, and then system simulation and experiments are done.3、Based on the mixed sensitivity design method, H∞ robust controller is designed for the3-DOF helicopter model. And then the simulation and experimental research are developed.Comparing the results of digital simulation and systems experiment, it is shown that the helicopter flight controller designed by H∞ control method based on mixed sensitivity can depress the external disturbance and parameter perturbation effectively; the system has strong robust stability and the trajectory of helicopter attitude tracks well.