Fourth Order Trajectory Tracking Control of a Quadrotor

In this paper, fourth order trajectory tracking control of aquadrotor is addressed. At first a nonlinear model of thequadrotor is presented. So, the nonlinear equations ofmotion are linearized about the equilibrium point of thesystem. By twice taking derivative of the translationalmotion equations with respect to the time, it can bedemonstrated that translational dynamics of the quadrotor isfourth order with respect to the roll torque, pitch torque andan auxiliary input. A state-feedback trajectory trackingcontroller is designed based upon the derived model whilehigher order states for feedback are calculated by thenonlinear equations of motion accordingly. Gains of theproposed controller can be tuned with any linear controldesign techniques such as LQR. Numerical simulationsorganized by the designed controller and nonlinear model ofthe quadrotor are implemented to exhibit capabilities of theproposed control scheme.