Fourth Order Trajectory Tracking Control of a Quadrotor

In this paper, fourth order trajectory tracking control of a quadrotor is addressed. At first a nonlinear model of the quadrotor is presented. So, the nonlinear equations of motion are linearized about the equilibrium point of the system. By twice taking derivative of the translational motion equations with respect to the time, it can be demonstrated that translational dynamics of the quadrotor is fourth order with respect to the roll torque, pitch torque and an auxiliary input. A state-feedback trajectory tracking controller is designed based upon the derived model while higher order states for feedback are calculated by the nonlinear equations of motion accordingly. Gains of the proposed controller can be tuned with any linear control design techniques such as LQR. Numerical simulations organized by the designed controller and nonlinear model of the quadrotor are implemented to exhibit capabilities of the proposed control scheme.