Design of Decoupling and Nonlinear PD Controller for Cruise Control of a Quadrotor

Quadrotor is often used to accomplish various missions related to surveillance, territory mapping, search and rescue, and other purposes. Quadrotor is a nonlinear system with multiple input multiple output and has stability issue due to external disturbance. These characteristics lead to difficulty in cruise control of quadrotor automatically. Decoupling method is used to eliminate the interaction of other control on rotational motion, then the roll, pitch, and yaw angle can be controlled independently. Nonlinear PD controller is obtained from invers model of control signal on a quad rotor and it is used to control the translational motion in x and y axis with nonlinear dynamics because of the influence the rotational angle. Simulation results show that the proposed method can eliminate the control interaction of roll, pitch and yaw angle, hence it works like single input single output system and translational motion on x and y axis can achieve the expected trajectory precisely.