Robust flight control of small-scale unmanned helicopter

A robust autonomous flight controller is proposed for a small-scale unmanned helicopter, THeli260. The controller is designed base on the inner-outer loop architecture. The inner-loop controls the attitudes and the outer-loop controls the translational trajectories of the helicopter. Based on a comprehensive nonlinear model of the small-scale unmanned helicopter, the inner and outer-loop dynamics are both regarded as nominal single-input single-output linear systems. The nonlinear uncertainties, coupling effects, parameter perturbations, and external disturbances are considered as equivalent disturbances. By employing the signal compensation method, robust controllers of the inner and outer-loop are both designed with two parts: a proportional-derivative controller and a robust compensator. The proposed controller can achieve top level control performance according to the ADS-33E-PRF military rotorcraft standard. Actual flight tests are conducted to check the effectiveness of the proposed robust flight controller.