Theory and experiments on robust LQR attitude control of a 3-DOF lab helicopter

This paper presents theory analysis and experimental results of a robust linear quadratic regulator (LQR) attitude control strategy for a three degree-of-freedom (DOF) lab helicopter. The control goal is to acquire the optimal performances in mild maneuvers, as well as having them preserved under aggressive maneuvers. A novel controller is proposed with three parts: a nominal feedforward controller, a nominal LQR state feedback controller and a robust compensator. The nominal parts are applied to deal with a nominal linear error system derived by linearizing parameters and the robust compensator is designed to restrain the effect of uncertainties and nonlinear properties. Theory proof and experimental results demonstrate the effectiveness of the control strategy implemented on the 3-DOF helicopter from Quanser Company.