Trajectory Tracking Control of a Quadcopter UAV Using Nonlinear Control

Recently trajectory tracking control of a quadcopter has been paid attention by academic and industry. This paper proposes two different strategies for trajectory tracking control of a quadcopter system implementing nonlinear control theory. The first approach is based on the integral backstepping technique, the second proposed one is an LQI (Linear Quadratic Integral) optimal controller with a feedback linearization so as to deal with the nonlinearity and the coupling components of the quadcopter state variables. The control laws for trajectory tracking using the proposed two strategies were validated by simulation and experimental results obtained from a quadcopter test bench. Simulation results show a comparison between the performance of each of the two control laws depending on the nonlinear model of the quadcopter system under investigation; the trajectory tracking has been achieved properly for different types of trajectories in presence of unknown disturbances. Simulation and practical results have shown coincided tracking with the command signals of the desired attitude. Superior tracking control has been exhibited with the proposed LQI optimal controller. It has been also noted that the proposed control approach exhibits an inherited decoupling control action, for which the control of one axis angle has relieved the dynamic coupling effect on the other two axes. Furthermore, intensive practical results have demonstrated the robustness of the proposed controller.