Precise Attitude Control for Unmanned Helicopter Based on Extended State Observer

A precise attitude control method is designed based on ESO (extended state observer) for the unmanned helicopter to reject disturbances caused by the model parameter uncertainty and electromagnetic interference. The uncertain part of the attitude channel and the external compound disturbance are considered as the lumped disturbance, which is estimated in real time by the designed ESO, and is eliminated by introducing a state feedback controller. The experiment results show that the attitude angle can be rapidly tracked from 0° to 5° in 0.1 s without overshoot. Finally, the designed controller is applied to the self-designed high-precision unmanned system, and the fully autonomous fixed-point hovering and tracking flight are implemented under the condition that the system parameters vary.