Robust nonlinear H/sub /spl infin// decoupling control of flight vehicle in hovering

Although longitudinal and lateral dynamics of helicopters in hovering are highly nonlinear and severely coupled, we show that the nonlinear six degree-of-freedom H/sub /spl infin// controller designed for hovering helicopter can be exactly separated into two three degree-of-freedom controllers: one for translational motion and the other for rotational motion.