Backstepping Control of an Unmanned Helicopter Subjected to External Disturbance and Model Uncertainty

A helicopter is a highly nonlinear system. Its mathematical model difficult to establish accurately, especially the complicated flapping dynamics. In addition, forces and moments exerted on fuselage are very vulnerable external disturbances like wind gust when flying in outdoor environment. This paper proposes composite control scheme which consists of backstepping controller an extended state observer (ESO) handle above problems. The stability closed-loop system can be guaranteed based Lyapunov theory. nonlinearities treated as lumped disturbance. Meanwhile, ESO employed compensate influence by estimating disturbance real-time. Numerical simulation results presented demonstrate that algorithm achieve accurate agile attitude tracking under even with uncertainties. When coming flight test, block dropping device was designed generate quantifiable replicable disturbance, experimental indicate introduced reject rapidly track given command precisely.