Nonlinear control of an autonomous quadrotor unmanned aerial vehicle using backstepping controller optimized by particle swarm optimization

Quadrotor unmanned aerial vehicle (UAV) is an unstable nonlinear control system. Therefore, the development of a high performance controller for such a multi-input and multi-output (MIMO) system is important. The backstepping controller (BC) has been successfully applied to control a variety of nonlinear systems. Conventionally, control parameters of a BC are usually chosen arbitrarily. The problems in this method are the adjustment is time demanding and a designer can never tell exactly what are the optimal control parameters should be selected. In this paper, the contribution is focused on an optimal control design for stabilization and trajectory tracking of a quadrotor UAV. Firstly, a dynamic model of the aerial vehicle is mathematically formulated. Then, an optimal backstepping controller (OBC) is proposed. The particle swarm optimization (PSO) algorithm is used to compute control parameters of the OBC. Finally, simulation results of a highly nonlinear quadrotor system are presented to demonstrate the effectiveness of the proposed control method. From the simulation results it is observed that the OBC tuned by PSO provides a high control performance of an autonomous quadrotor UAV