Rejecting the disturbances due to the umbilical's traction in ROV's control

Consider the problem of decoupling the effect of the umbilical's traction from the position of a ROV by means of feedback. The problem is first studied with respect to a linearized model of the ROV. Geometric methods show that exact decoupling is not possible, while approximate decoupling can be achieved by means of high-gain feedbacks. The relations with an H/sub /spl infin// approach to the same problem are discussed and the effectiveness of the design methodology with respect to the nonlinear model is shown by means of simulations.