Attitude Control of a Quadrotor Using Implementation of Modified PID and Sliding Mode Controllers

Attitude control of the UAV’s is basis of the of many control systems such as position control, trajectory traking, traking moving targets and obstacle avoidance. Hence, one of the most important parts of the UAV's control is designing an appropriate and efficient controller, so that system being able to eliminates or reduces external disturbances, mechanical underactuation, changes in the model or physical parameter and interactions between its subsystems. In this paper, the attitude control problem is studed. For this purpose, the dynamics model of a quadrotor is derived by using Newton-Euler mtethod and the required parameters of the model such as moment of inertia, thrust and drag torque coefficient identified by experimental methods and an actual physical sample. Then, modidied PID and sliding mode controllers are designed to provide attitude traking for quadrotor and performance of these controllers is investigated in the presence of disturbance and sensors noise. Finally, the desgned cotrollers are implemented on a real 3DOF system and the experimental results are compared with the simulation results.