A Super-Twisting-Sliding-Mode Controller for four-rotor UAV

Four-rotor UAV has the problem of being susceptible to wind disturbance and coupling of its own channel in the flight process, which will have a negative impact on its trajectory tracking. This paper focus on the trajectory tracking in the flight process of the four-rotor UAV, a super twisting sliding mode(STSM) composite controller based on the extended state observer(ESO) is designed for the position loop of the UAV, attitude loop adopts the traditional cascade PID controller. First, the ground coordinate system is established as a reference for trajectory tracking, and then the kinematics modeling of the UAV system is carried out by using Newton-Euler method, and the desired trajectory is entered into the position controller. At the same time, an ESO is established based on a general UAV model, and disturbances and internal channel coupling of the UAV are observed and fedback to the corresponding controller. Finally, the composite proposed controller is simulated to track a desired trajectory. Based on the simulation results,draw the conclusion of the composite controller this paper proposed improved the robustness of the four-rotor UAV in the trajectory tracking scenario.