Trajectory Tracking Control of Quadrotor using Fractional-Order Fuzzy PID Controller in the Presence of Wind Disturbance

Quadrotor is one the most popular models of unmanned aerial vehicles with four actuated propellers which has a simple, light weight, small mechanical structure and high maneuverability. However, its nonlinear under-actuated dynamics needs more advanced controllers for rejection of external disturbances, balancing and precise trajectory tracking. In particular, the under-actuated subsystem of the quadrotor's dynamics needs a fast response without overshoot and steady state error. In this paper, fuzzy fractional-order proportional-integral derivative (FOFPID) controller is designed for quadrotor control system using fuzzy and fractional order systems to improve response speed, tracking accuracy and system robustness respect to the conventional PID controller. Controller architecture of the under-actuated subsystem of the quadrotor's dynamics is designed based on the inner-outer loop control theory which is employed explicit and analytical inverse kinematic of system to connect the inner and outer loops. Also, dynamics of the motors and actuators saturation are considered in the quadrotor’s dynamics model and their effects are studied on the controllers' performance. In order to evaluate tracking performance of controllers, trajectory of an eight aerial maneuver is designed and controllers’ performance is assessed in the absence and presence of wind disturbance. Trajectory tracking accuracy of the controllers is studied according to the maximum absolute error and integral of absolute error criterions and is compared that shows the proposed FOFPID controller has successfully improved performance of the quadrotor system.