A robust LQR control strategy for the effective trajectory tracking of a 3-DOF laboratory model helicopter is discussed. Parametric uncertainties and various external disturbances are considered in the system. The newly designed control strategy includes the feedback control by linear quadratic regulation (LQR) controller and the disturbance compensation technique. Initially the linearized model of the nominal nonlinear laboratory helicopter is obtained and a linear quadratic regulation controller is designed for the nominal linear system, and a disturbance compensator is added to the system, to reduce the effects of the external disturbances. The trajectory tracking errors of the system is reduced under various disturbances by using the proposed scheme.
S. Sini, A. Vivek, and Nandagopal, J. L., “Trajectory tracking of 3-DOF lab helicopter by robust LQR”, in 2017 International Conference on Circuit ,Power and Computing Technologies (ICCPCT), Kollam, India, 2017.