Estimation and Control of a Tilt-Quadrotor Attitude

The aim of the present work is to continue the development of the prototype ALIV3, focusing on the estimation and control of the attitude. First the differences in motion and configurations of a tilt-quadrotor in relation with a common quadrotor are explained. The mass properties and actuators of the prototype are measured through tests specially developed. In the identification of the motors the influence of the temperature and the battery discharge were considered. The Tilt-Quadrotor is equipped with 3-axes accelerometer, 3-axes gyroscope, 3axes compass and a barometer, all included in the IMU shield of the Ardupilot Mega 1 (APM 1) .These sensors are modeled using real sensor measurements to get a better approximation to the real case. The model of the system has been linearized around hovering. Then the model is implemented in Simulink. First a 12 states LQR controller was developed to achieve the stabilization of the ALIV3. Because the model was not either fully controllable or observable, it was developed a 6 states LQR controller. The model is simulated using ideal sensor in the continuous and discrete case. Once the controller was tuned, it was simulated the model with estimation feedback introducing the Extended Kalman Filter (EKF). The final results suggest that the LQR and the EKF combined could stabilize the ALIV3. Index Terms – Quadrotor, Tilting rotor, Extended Kalman Filter, Linear-Quadratic-Regulator, Identification.