Backstepping control with exact 2-sliding mode estimation for a quadrotor unmanned aerial vehicle

This paper presents the design of a backstepping controller using sliding mode estimation technique which aims to simplify the control procedure. This approach, applied to a quadrotor unmanned aerial vehicle, differs from standard backstepping in that the virtual control inputs are designed based on estimates of the previous virtual control inputs. This eliminates the need to take derivatives of the system dynamics, which simplifies the control law. The estimation design is based on the exact second-order sliding mode differentiator. The controller objective is to achieve good tracking of desired positions and yaw angle while keeping the stability of the pitch and roll angles. The design methodology is based on the Lyapunov stability. Simulation results demonstrate the effectiveness of the proposed approach.