Computer aided design of a control system for a hovercraft

The JEFF(B) is hovercraft air cushion vehicle that was designed to be an amphibious assault vehicle for the Navy. It proved difficult to handle during engineering trials due to the number of controls that the pilot had to manipulate and the fact that instabilities were encountered during turns. To correct the operational difficulties, an Integrated Control System was designed for the JEFF(B) hovercraft. Utilizing a computer aided design approach, optimal nonlinear and linear controls were developed for the high speed turn, low speed turn and translation modes. The JEFF(B) turn rate and translation performance were maximized, and the hovercraft was stabilized over the entire operating regime. The original four cockpit controls were reduced to two (independently commanded turn rate and velocity). Nonlinear simulation results and actual sea tests demonstrated dramatic improvements in handling qualities with the Integrated Control System.