Modeling and LQR control of small unmanned helicopter

Small unmanned helicopter is a MIMO, strong coupling and nonlinear system. In this paper, state-space model of pitch and roll channels is built, model parameters are identified by frequency method and manned flight evaluation is performed. Compared to the single-channel identificated method, this model involves coupling effect within roll and pitch channels and possesses more accuracy. Based on the identified model, a linear quadratic regulator (LQR) with reduced order observer as attitude controller and state feedback velocity-position controller is designed. Real flight results demonstrate the accuracy of identified model further as well as the feasibility of the proposed control strategy.