Nonlinear robust observer based control of twin rotor control system with friction

A nonlinear robust observer based controller design for twin rotor control system (TRCS) is demonstrated in this paper. The TRCS is an uncertain system with high nonlinearity and strong coupling effects. The TRCS is a replication of a helicopter to some extent. Due to high coupling effect, the controller design of TRCS is challenging as well as interesting. As all the state variables of TRCS are unmeasurable, a nonlinear observer based controller is designed using backstepping technique. A highly nonlinear friction term is introduced in the TRCS to illustrate the robustness of the proposed controller. Finally elaborated simulation results are shown which demonstrate the effectiveness of the control strategies. Simulation results highlight the ability of the proposed observer based controller to tackle the nonlinearity present in the system. Control effort and degree of tracking is analyzed and compared under the effect of friction and without the effect of friction.