Robust Geometric Control of a Helicopter using Sliding Mode Control

This paper presents a robust attitude controller for a small-scale helicopter based on sliding mode control theory. The attitude dynamics is considered to be evolving on non Euclidean space to develop a globally defined controller. The attitude of fuselage is represented by the rotation matrix. An interconnected hybrid model of a helicopter is considered to be consisting of fuselage modeled as a single rigid body and rotor modeled as a disc whose flapping motion is represented by first order dynamics. It is assumed that an unknown disturbance is acting on the rotor. Sliding mode theory is employed to develop a robust controller assuming that the bound of external disturbance is known. The convergence of controller is shown by using Lyapunov theory. The performance of proposed approach is demonstrated through numerical simulations.