Manoeuvrable Gantry Tractor Comprising a "Chorus Line" of Synchronised Modules

A method of automatically manoeuvring a gantry tractor through right angle turns, U-turns and narrow gates is described. In order to maxmise traction and maneuverability both the wheel angle steering effect and the drive wheel speed steering effect are integrated. This technique produced identical and cooperative redundant steering systems. In addition, through this work, a second level of cooperative redundancy can be achieved when the angle between the longitudinal axes of adjacent modules is also positively controlled. The advantage of cooperative redundancy is that when any steering system begins to fail it is reinforced by the other steering system.