Robust H∞ flight control of small-scale unmanned helicopter for WCICA 2014 proceedings published by IEEE

Based on the inner-outer loop structure, a robust H_∞ flight controller is designed for small-scale unmanned helicopters. Under the hovering flight condition, the small-scale unmanned helicopter dynamic model is linearized. External disturbances, nonlinear uncertainties, and parameter uncertainties are considered as an equivalent disturbance. The velocity and the yaw angular rate are controlled by the inner-loop robust controller, which contains two parts: a state-feedback H_∞ controller and a robust compensator. The state-feedback H_∞ controller is applied to stabilize the helicopter and achieve good robust properties against external disturbances. The robust compensator is used to restrain the effects of the equivalent disturbance. The outer-loop controller is designed by the proportional-integral-derivative control technique to achieve desired position and yaw angle tracking properties. Actual flight tests are conducted to check the effectiveness of the proposed robust flight controller.