Experimental investigation of nonlinear controllers applied to a 3DOF hover: SMC via ALQR approach

This paper presents an application of sliding mode controllers obtained via amplified linear quadratic regulator (ALQR) strategy to a hover with three degrees of freedom. The purpose of the designed control system is to track reference trajectories and ensure performance and stability in spite of disturbance, noise and unmodeled dynamics. Simulations were performed using MATLAB/Simulink in order to verify/compare the performance of the nonlinear controllers proposed. For validation of the algorithm a didactic plant (3DOF Hover) was chosen produced by Quanser Consulting, that simulates typical behaviors of an VTOL (“vertical taking-off landing”) aircraft, also known as X4-flyer. The dynamic of the hover can be described by a 6th order model taking as state variables the angles of yaw, pitch, roll and associated rates. The experiments showed that designed nonlinear controllers using sliding mode control via ALQR are robust to noises and for a range of unmodeled nonlinearities.