The nonlinear disturbance observer-based control for small rotary-wing unmanned aircraft

Abstract

As a complex system, control performance of small rotary-wing unmanned aircraft is easily affected by measurement errors and environment disturbances. This paper proposes a nonlinear disturbance observer-based control to improve control performance. The constant and harmonic disturbance that is generated by the exogenous system with modeling perturbation can be estimated and rejected effectively. The random disturbance with certain bound can be reduced by the feedback control. By solving linear matrix inequality, the parameters for feedback control and nonlinear disturbance observer can be selected simultaneously. Therefore, the system stability can be guaranteed and the control performance can be improved effectively. The effectiveness of the nonlinear disturbance observer-based control is proved by a series of flight tests. Compared with feedback control, the disturbance observer-based control yields a better tracking performance in the presence of disturbances.