Tail-Sitter UAV Attitude Disturbance Rejection Control with Compensating Function Observer Based Additive State Decomposition Controller

This paper, a control method for suppressing attitude disturbance of a tail-sitter UAV is proposed. Due to the special structure of the UAV and the change of pitch angle during the transition, nonlinear terms and unwanted disturbance are introduced, which bring additional challenges to the controller design. The nonlinear and disturbance terms are placed in the primary system according to the principle of additive decomposition controller (ASD), then the matching and non-matching disturbance in the primary system are estimated using compensating function observer (CFO), and then The controllers of the primary and secondary systems can be obtained from the pole configurations, and the original system controllers are obtained by summing up these two controllers. Simulation results demonstrate that this control method has superior tracking effect in the face of large matching and non-matching disturbances compared with the traditional PID control algorithm.