Robust H∞ decoupling hover control of uncertain nonlinear helicopter

This paper propose a new attempt to consider nonlinear H ∞ control of helicopter with plant uncertainty. The plant to be controlled is a hovering helicopter described by six-degree-of-freedom nonlinear dynamics with plant uncertainties due to the variation of moments of inertia caused by fuel consumption and payload operation. Taking into account nonlinear effect of motion in the presence of plant uncertainty, we show in this paper that the sixdegree-of-freedom nonlinear H ∞ controller can be exactly decoupled into two three-degree-of-freedom controllers, one for translational motion and the other for rotational motion, even though longitudinal and lateral dynamics of the helicopters in hovering are highly nonlinear and severely coupled.