Cascaded Trajectory Tracking Control for A Quadcopter UAV with Consideration of Actuator Dynamics

In this paper, a control method to solve the attitude and position control problems for a quadcopter UAV under two different flight scenarios is proposed. Firstly, both its nonlinear and linearized flight dynamic model are established. Then, an inner-and-outer loop linear quadratic regulator (LQR) algorithm is invoked for the attitude and position control of the quadcopter respectively. In our control structure, by employing its decoupled linearized flight dynamics model, attitude control loop is considered as an inner loop while position control loop is served as an outer loop. The desired attitude of the inner loop is adopted as the control input of the outer loop. Performance of the LQR control structure is verified by numerical simulations test based on a quadcopter UAV, and simulation results show that the proposed LQR method is stable and effective.