Design of LQR Controller for 3D Trajectory Tracking of Octocopter Unmanned Aerial Vehicle
The paper deals with the mathematical modeling and control of an unmanned aerial vehicle (UAV), called octocopter, based on a linear quadratic regulator (LQR). The complex multivariable and nonlinear UAV model is linearized and represented in the state space form. Optimal LQR control system, which is composed of combination the altitude (UAV height - ${z}$ position) and attitude (orientation) controllers, was first designed. Then, this system is extended to provide an additional control of the translation movement in ${x}$ and ${y}$ directions. The proposed LQR control structure is capable of controlling the UAV for all position and orientation coordinates while tracking desired 3D trajectory. Simulation studies are performed on the UAV model where the designed LQR controller has been compared with previously developed PD controller.