Robust control for lateral and longitudinal channels of small-scale unmanned helicopters

Lateral and longitudinal channels are two closely related channels whose control stability influences flight performance of small-scale unmanned helicopters directly. this paper presents a robust control approach for lateral and longitudinal channels in the presence of parameter uncertainties and exogenous disturbances. the proposed control approach is performed by two steps. first,by performing system identification in frequency domain,system model of lateral and longitudinal channels can be accurately identified. then,a robust h∞ state feedback controller is designed to stabilize the helicopter in lateral and longitudinal channels simultaneously under extraneous disturbances situation. the proposed approach takes advantages that it reduces order of the controller by preestimating some parameters (like flapping angles) without sacrificing control accuracy. numerical results show the reliability and effectiveness of the proposed method. © 2015 bao feng.